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Asbestos in cooling-tower waters
Energy Technology Data Exchange (ETDEWEB)
Lewis, B.A.G.
Fill material in natural- or mechanical-draft cooling towers can be manufactured from a variety of materials, including asbestos cement or asbestos paper. To aid in the environmental impact assessment of cooling towers containing these asbestos types of fill, information on these materials was obtained from cooling-tower vendors and users. Samples of makeup, basin, and blowdown waters at a number of operating cooling towers were obtained, and identification and enumeration of asbestos in the samples were performed by transmission electron microscopy, selected-area electron diffraction, and energy-dispersive x-ray analysis. Asbestos fibers were detected in cooling-tower water at 10 of the 18 sites sampled in the study. At all but three sites, the fibers were detected in cooling-tower basin or blowdown samples, with no fibers detected in the makeup water. The fibers were identified as chrysotile at all sites except one. Concentrations were on the order of 10/sup 6/ to 10/sup 8/ fibers/liter of water, with mass concentrations between <0.1 ..mu..g/liter to 37 ..mu..g/liter. The maximum concentrations of asbestos fibers in air near ground due to drift from cooling towers were estimated (using models) to be on the order of asbestos concentrations reported for ambient air up to distances of 4 km downwind of the towers. The human health hazard due to abestos in drinking-water supplies is not clear. Based on current information, the concentrations of asbestos in natural waters after mixing with cooling-tower blowdown containing 10/sup 6/ to 10/sup 8/ fibers/liter will pose little health risk. These conclusions may need to be revised if future epidemiological studies so indicate.
Asbestos in cooling-tower waters. Final report
International Nuclear Information System (INIS)
Water discharges from cooling towers constructed with asbestos fill were found to contain chrysotile--asbestos fibers at concentrations as high as 108 fibers/liter. The major source of these fibers, appears to be the components of the towers rather than the air drawn through the towers or the makeup water taken into the towers. Suggested mechanisms for the release of chrysotile fibers from cooling-tower fill include freeze-thaw cycles and dissolution of the cement due to acidic components of the circulating water. Ash- or other material-settling ponds were found to reduce asbestos-fiber concentrations in cooling-tower effluent. The literature reviewed did not support the case for a causal relationship between adverse human health effects and drinking water containing on the order of 106 chrysotile--asbestos fibers/liter; for this and other reasons, it is not presently suggested that the use of asbestos fill be discontinued. However, caution and surveillance are dictated by the uncertainties in the epidemiological studies, the absence of evidence for a safe threshold concentration in water, and the conclusive evidence for adverse effects from occupational exposure. It is recommended that monitoring programs be carried out at sites where asbestos fill is used; data from such programs can be used to determine whether any mitigative measures should be taken. On the basis of estimates made in this study, monitoring for asbestos in drift from cooling toring for asbestos in drift from cooling towers does not appear to be warranted
Water distribution in cooling towers: Characterization of industrial spray nozzles
International Nuclear Information System (INIS)
The distribution of water to the top of counterflow fill of cooling towers is a key aspect of the performance of the whole cooling systems. It is a function of nozzle design, nozzle installation, height of the spray zone, and the structural cleanliness of the spray chamber. The impact of water distribution on performance is a combination of uniformity of water distribution, air-side pressure drops, and heat transfer occurring in the spray zone. As the matter of fact, simulation of cooling tower behavior by means of a two-dimensional code showed that droplet size in the spray zone plays an important role on tower performances. In spite of its practical importance, the water distribution process has not been studied enough. In this work four practical nozzels were studied experimentally and, on the basis of the results, some performers parameters have been defined and evaluated, which can be related to heat transfer and pressure drops in the spray zone of a cooling tower
Deuterium- and 18O-content in the cooling water of power station cooling towers
International Nuclear Information System (INIS)
The 0-18/0-16 and D/H isotope ratios of water from two different cooling towers were determined by mass spectrometry. The observed isotope fractionation corresponds to that known from natural evaporation or transpiration processes: cooling tower I: delta(D) = 46.8 per thousand, delta(18O) = 7.6 per thousand cooling tower II: delta(D) = 33.9 per thousand delta(18O) = 5.7 per thousand Evaluation of simple compartment models of a cooling tower and a distillation device suggests that there exists some isotope discrimination within the open trickling unit of a cooling tower analogous to that in a rectification column. In a real cooling tower, however, this effect is compensated largely by the recycling of the cooling water, resulting only in a small enrichment of the heavy isotopes. This can be understood as the result of three partial effects: 1) a fractionation in the vapor pressure equilibrium, 2) a kinetic effect due to diffusion of the water vapor into a turbulent atmosphere, and 3) an exchange effect which is proportional to relative humidity. This low enrichment of the heavy isotope excludes the technical use of cooling towers as isotope separation devices. (orig.)
Calculating the evaporated water flow in a wet cooling tower
International Nuclear Information System (INIS)
On a cooling tower, it is necessary to determine the evaporated water flow in order to estimate the water consumption with a good accuracy according to the atmospheric conditions, and in order to know the characteristics of the plume. The evaporated flow is small compared to the circulating flow. A direct measurement is very inaccurate and cannot be used. Only calculation can give a satisfactory valuation. The two usable theories are the Merkel's one in which there are some simplifying assumptions, and the Poppe's one which is more exact. Both theories are used in the numerical code TEFERI which has been developed and is run by Electricite de France. The results obtained by each method are compared and validated by measurements made in the hot air of a cooling tower. The consequences of each hypothesis of Merkel's theory are discussed. This theory does not give the liquid water content in the plume and it under-estimates the evaporated flow all the lower the ambient temperature is. On the other hand, the Poppe's method agrees very closely with the measurements as well for the evaporated flow than for the liquid water concentration. This method is used to establish the specific consumption curves of the great nuclear plants cooling towers as well as to calculate the emission of liquid water drops in the plumes. (author). 11 refs., 9 figs
Coagulation chemistries for silica removal from cooling tower water.
Energy Technology Data Exchange (ETDEWEB)
Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom
The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.
Numerical study of coupled heat and mass transfer in geothermal water cooling tower
International Nuclear Information System (INIS)
Cross flow mechanical cooling towers, widely spreads all over the south region of Tunisia are used for cooling geothermal water for agriculture and domestic ends. These towers are sized empirically and present several problems in regard to operation and electrical energy consumption. This work aims to study the thermal behaviour of this type of cooling towers through a developed mathematical model considering the variation of the water mass flow rate inside the tower. The analysis of the water and air temperatures distribution along the cooling tower had underlined the negative convection phenomenon at a certain height of the tower. This analysis has shown also that the difference in water temperature between the inlet and the outlet of the tower is much higher than the one of air due to the dominance of the evaporative potential compared to the convective one. In addition, the variations of the air humidity along the cooling tower and the quantity of evaporated water have been investigated. The loss of water by evaporation is found to be 5.1% of the total quantity of water feeding the cooling tower. Interesting future prospects are expected for validation of the developed model to optimize the operating of the cooling tower
Ecological impact of chloro-organics produced by chlorination of cooling tower waters
International Nuclear Information System (INIS)
Experimental results of the initial assessment of chlorine-containing compounds in the blowdown from cooling towers and the possible mutagenic activity of these compounds are reported. High-resolution liquid chromatographic separations were made on concentrates of the blowdown from the cooling tower at the High Flux Isotope Reactor (HFIR) and from the recirculating water system for the cooling towers at the Oak Ridge Gaseous Diffusion Plant (ORGDP), Oak Ridge, Tennessee. The chromatograms of chlorinated cooling waters contained numerous uv-absorbing and cerate-oxidizable constituents that are now being processed through a multicomponent identification procedure. Concentrates of the chlorinated waters are also being examined for mutagenic activity
Resonance in the water circuit of a cooling tower
International Nuclear Information System (INIS)
During the start-up tests of a cooling-tower circuit pressure resonance took place. With the aid of a mathematical model this resonance was investigated and the results were analyzed. The elastic behaviour of leaking non-return valves appeared to be responsible for the onset of the resonance. The preventive function of a by-pass around each valve, was analyzed. In the final startup test the leakage flow was eliminated and a by-pass had been installed for safety reasons. The measures taken proved to be satisfactory for all operating conditions. (orig.)
Water vapour rises from the cooling towers for the ATLAS detector at Point 1
Brice, Maximilien
Electronics on the ATLAS detector produce heat when the experiment is running. An elaborate cooling system keeps the detector from overheating. On the surface, the warm water vapour that rises from the detector 100metres underground is clearly visible from the ATLAS cooling towers on the CERN Meyrin site in Switzerland.
The water tower, being built on the highest point of the site, 460.5 m above the sea level. The tank will hold 750 m3 of water, and the tower will be topped by a knob which can serve as a geological survey reference mark.
Agricultural utilization of lime residues from cooling tower make-up water treatment
International Nuclear Information System (INIS)
The cooling towers of the two 1300 MW boiling water reactors at Grundremmingen Units B and C require together about 2.2 m3/s of cooling tower make-up water. This water is abstracted from the Danube and subjected to slow decarbonization. About 150 to 180 tons of residual lime are produced daily from this process. This dry substance consists of up to 90% calcium carbonate. Intensive chemical and agrotechnical investigations have demonstrated that this material is most suitable for agricultural utilization as fertilizer lime. (orig.)
Evaluation Of Cooling Tower Degradation
International Nuclear Information System (INIS)
Cooling tower degradation has been evaluated for the last 10 years. Its heat transfer capacity has been decreasing after several years of operation due to aging. Evaluation is carried out by calculating the degradation rate, namely the annual increase of outlet temperatures of the cooling tower. Data was randomly taken daily at 15 MW reactor power. Data was taken after the reactor operation of � 8 hours. Evaluation since 1990 shows that the degradation rate is nearly one degree per year. This degradation can be by minimized, replacement of damaged components, non-excessive operation and design modification of the cooling tower namely by extending the period of contract between water and air
Experience with a plant for the treatment of cooling tower make-up water
International Nuclear Information System (INIS)
Cooling tower make-up water treatment is based on the coprecipitation of the river water impurities and iron hydroxide in a continuous flow process. Clean water and watery slurry are separated on parallel-plate separators and subsequently then treated further. The parallel separators permit a compact form of construction of the whole plant and thereby open up possibilities for, inter alia, weather protection for uninterrupted winter operation. In summary, cooling tower make-up water treatment has in its first full year of operation satisfactorily fulfilled the requirement of reliable service water supply at all times. However, the operation of the plant was too costly in maintenance; this was the reason for a multiplicity of optimization measures. (orig.)
Cooling towers: a bibliography
International Nuclear Information System (INIS)
This bibliography cites 300 selected references containing information on various aspects of large cooling tower technology, including design, construction, operation, performance, economics, and environmental effects. The towers considered include natural-draft and mechanical-draft types employing wet, dry, or combination wet-dry cooling. A few references deal with alternative cooling methods, principally ponds or spray canals. The citations were compiled for the DOE Energy Information Data Base (EDB) covering the period January to December 1980. The references are to reports from the Department of Energy and its contractors, reports from other government or private organizations, and journal articles, books, conference papers, and monographs from US originators
Directory of Open Access Journals (Sweden)
A Haddad
Full Text Available Cooling towers are extensively used to evacuate large quantities of heat at modest temperatures through a change of phase of the flowing cooling fluid. Based on this classical principle, the present study investigates the influence of salty water on the heat exchange produced. For that purpose, experiments are carried out using fresh and salty water. Furthermore, a comparison with the results produced through an approach involving the solution of energy equation involving the flow of air on an evaporating film of fluid. The detailed results show a preponderance of fresh water over the salty.
Hydraulic works study of Golfech cooling towers
International Nuclear Information System (INIS)
The GOLFECH Nuclear Power Plant cooling towers (PWR 2 x 1300 MWe), built by SCAM for EDF (French National Electricity Authority), have certain characteristics, including: tower height - 178.50 metres; shell support - made up of a profiled lintel resting on piles; cooled water recovery system installed immediately below the fill; and cold water basin built outside the cooling tower. This paper deals only with the hydraulic circuit design (warm water inlet, cooled water recovery, cooled water return) with particular emphasis on the limitations of conventional methods of hydraulic sizing and, the necessity to carry out tests using models in order to dimension such works
Biofilm formation on galvanized steel by SRB isolate obtained from cooling tower water
O?zu?o?lmez, Derya; C?otuk, Ays??n
In this study, we investigated biofilm formation on galvanized steel coupons by anaerobic bacteria isolate including sulphate-reducing bacteria (SRB) isolated from cooling tower water in a lab-scaled experimental setup. The test coupons were exposed to the culture of anaerobic bacteria isolate during 744 hours. In the course of time, anaerobic bacteria isolate could form biofilm on galvanized steel coupons. According to the statistical analyses, there was no significant difference between ses...
A review of recently reported cooling tower plume models yields none that is universally accepted. The entrainment and drag mechanisms and the effect of moisture on the plume trajectory are phenomena which are treated differently by various investigators. In order to better under...
Energy Technology Data Exchange (ETDEWEB)
Smith, C.; Brigmon, R.
Legionnaires disease is a pneumonia caused by the inhalation of the bacterium Legionella pneumophila. The majority of illnesses have been associated with cooling towers since these devices can harbor and disseminate the bacterium in the aerosolized mist generated by these systems. Historically, Savannah River Site (SRS) cooling towers have had occurrences of elevated levels of Legionella in all seasons of the year and in patterns that are difficult to predict. Since elevated Legionella in cooling tower water are a potential health concern a question has been raised as to the best control methodology. In this work we analyze available chemical, biological, and atmospheric data to determine the best method or key parameter for control. The SRS 4Q Industrial Hygiene Manual, 4Q-1203, 1 - G Cooling Tower Operation and the SRNL Legionella Sampling Program, states that 'Participation in the SRNL Legionella Sampling Program is MANDATORY for all operating cooling towers'. The resulting reports include L. pneumophila concentration information in cells/L. L. pneumophila concentrations >10{sup 7} cells/L are considered elevated and unsafe so action must be taken to reduce these densities. These remedial actions typically include increase biocide addition or 'shocking'. Sometimes additional actions are required if the problem persists including increase tower maintenance (e.g. cleaning). Evaluation of 14 SRS cooling towers, seven water quality parameters, and five Legionella serogroups over a three-plus year time frame demonstrated that cooling tower water Legionella densities varied widely though out this time period. In fact there was no one common consistent significant variable across all towers. The significant factors that did show up most frequently were related to suspended particulates, conductivity, pH, and dissolved oxygen, not chlorine or bromine as might be expected. Analyses of atmospheric data showed that there were more frequent significant elevated Legionella concentrations when the dew point temperature was high--a summertime occurrence. However, analysis of the three years of Legionella monitoring data of the 14 different SRS Cooling Towers demonstrated that elevated concentrations are observed at all temperatures and seasons. The objective of this study is to evaluate the ecology of L. pneumophila including serogroups and population densities, chemical, and atmospheric data, on cooling towers at SRS to determine whether relationships exist among water chemistry, and atmospheric conditions. The goal is to more fully understand the conditions which inhibit or encourage L. pneumophila growth and supply this data and associated recommendations to SRS Cooling Tower personnel for improved management of operation. Hopefully this information could then be used to help control L. pneumophila growth more effectively in SRS cooling tower water.
The future cooling tower; Fremtidens koeletaarn
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Ibsen, C.H. (Vestas Aircoil A/S, Lem St. (Denmark)); Schneider, P. (Teknologisk Institut, AArhus (Denmark)); Haaning, N. (Ramboell A/S, Copenhagen (Denmark)); Lund, K. (Nyrup Plast A/S, Nyrup (Denmark)); Soerensen, Ole (MultiWing A/S, Vedbaek (Denmark)); Dalsgaard, T. (Silhorko A/S, Skanderborg (Denmark)); Pedersen, Michael (Skive Kommune, Skive (Denmark))
This project has designed and built a pilot-scale cooling tower with an output of up to 100 kW for which good correlation has been ascertained between measured and calculated values for output and pressure loss. The new cooling tower will save approximately 15% of electricity consumption compared with the widespread dry coolers. The pilot tower uses rainwater so that both water consumption and electricity consumption are saved in softening plants. On the basis of this cooling tower, models have been made and these have been implemented in PackCalc II in order to calculate electricity and other operating savings. (Energy 11)
Hydraulic cooling tower driver
International Nuclear Information System (INIS)
One of the weaknesses of present day cooling tower drives are fan wrecks caused by shaft couplings breaking, gear box malfunctions due to inadequate lubrication, gear tooth wear, and inaccessibility for inspection and routine maintenance. The hydro-drive eliminates these items from the drive train and puts the same electric motor HP at ground level close coupled to a hydraulic pump, filters, and oil reservoir. Hydraulic lines bring oil pressure to the hydraulic motor, which is more than 75% less weight than comparable gear boxes and presents a smooth practically trouble free performance. In this three cell installation, the original 75 horsepower motors and 18' diameter fans were cooling a total of 14,000 GPM which were CTI tested at 74.7% of capability. The upgrading and retrofit consisted of installing at ground level 100 horsepower motors, 22' diameter fans, 14' high velocity recovery fan cylinders, V PVC splash bars, and high efficiency cellular drift eliminators. Testing indicates a 92% tower now circulating 21,000 GPM instead of the original 14,000
Performance characteristics of a shower cooling tower
International Nuclear Information System (INIS)
This study was prompted by the need to design towers for applications in which, due to salt deposition on the packing and subsequent blockage, the use of tower packing is not practical. In contrast to conventional cooling towers, the cooling tower analyzed in this study is void of fill. By means of efficient atomization nozzles, a shower cooling tower (SCT) is possible to be applied in industry, which, in terms of water cooling, energy saving and equipment investing, is better than conventional packed cooling towers. However, no systematic thermodynamic numerical method could be found in the literature up to now. Based on the kinetic model and mass and heat transfer model, this paper has developed a one dimensional model for studying the motional process and evaporative cooling process occurring at the water droplet level in the SCT. The finite difference approach is used for three motional processes to obtain relative parameters in each different stage, and the possibility of the droplets being entrained outside the tower is fully analyzed. The accuracy of this model is checked by practical operational results from a full scale prototype in real conditions, and some exclusive factors that affect the cooling characteristics for the SCT are analyzed in detail. This study provides the theoretical foundation for practical application of the SCT in industry
Large cooling tower drift deposition
International Nuclear Information System (INIS)
A model for the determination of drift deposition around natural-draft cooling towers is presented. An application of the model in actual operating conditions indicates the effect of drift rate at the cooling tower outlet and weather conditions on the size and shape of wetted area. (author)
Technology to Facilitate the Use of Impaired Waters in Cooling Towers
Energy Technology Data Exchange (ETDEWEB)
Colborn, Robert
The project goal was to develop an effective silica removal technology and couple that with existing electro-dialysis reversal (EDR) technology to achieve a cost effective treatment for impaired waters to allow for their use in the cooling towers of coal fired power plants. A quantitative target of the program was a 50% reduction in the fresh water withdrawal at a levelized cost of water of $3.90/Kgal. Over the course of the program, a new molybdenum-modified alumina was developed that significantly outperforms existing alumina materials in silica removal both kinetically and thermodynamically. The Langmuir capacity is 0.11g silica/g adsorbent. Moreover, a low cost recycle/regeneration process was discovered to allow for multiple recycles with minimal loss in activity. On the lab scale, five runs were carried out with no drop in performance between the second and fifth run in ability to absorb the silica from water. The Mo-modified alumina was successfully prepared on a multiple kilogram scale and a bench scale model column was used to remove 100 ppm of silica from 400 liters of simulated impaired water. Significant water savings would result from such a process and the regeneration process could be further optimized to reduce water requirements. Current barriers to implementation are the base cost of the adsorbent material and the fine powder form that would lead to back pressure on a large column. If mesoporous materials become more commonly used in other areas and the price drops from volume and process improvements, then our material would also lower in price because the amount of molybdenum needed is low and no additional processing is required. There may well be engineering solutions to the fine powder issue; in a simple concept experiment, we were able to pelletize our material with Boehmite, but lost performance due to a dramatic decrease in surface area.
Application of Response Surface Methodology (RSM) for Optimization of Operating Parameters and Performance Evaluation of Cooling Tower Cold Water Temperature
Ramkumar RAMAKRISHNAN; Ragupathy ARUMUGAM
The performance of a cooling tower was analyzed with various operating parameters tofind the minimum cold water temperature. In this study, optimization of operating parameters wasinvestigated. An experimental design was carried out based on central composite design (CCD) withresponse surface methodology (RSM). This paper presents optimum operating parameters and theminimum cold water temperature using the RSM method. The RSM was used to evaluate the effectsof operating variables and their in...
Discussion on Energy-saving Applications of Fanless Cooling Tower
Directory of Open Access Journals (Sweden)
Kuang-Cheng Yu
Full Text Available Cooling tower is essential to both industrial development and comfortable living. Its development is closely related to human civilization and quality of life. To achieve the cooling effects and the efficiency performance of high inlet/outlet water temperature difference (?t of cooling towers, a number of modern high technologies have been applied, while the design of cooling towers focuses on lightweight, compact size, elegant appearance, and durability. This study studied the performance of fanless cooling tower when applied in a chiller cooling water system of the central air-conditioning in a hospital and discussed the problems and solutions that the fanless cooling tower encountered during practical use and explored whether there is any room to improve energy conservation according to the data recorded in the process of operation. This study also verified the performance and advantages as specified by the manufacturer to provide a reference to the design and installation of same type cooling towers in the future.
Survey of asbestos fibers in cooling tower waters at Goodyear Atomic Corporation
International Nuclear Information System (INIS)
Monitoring of the recirculating water (RCW) system at Goodyear Atomic Corporation has been performed since late 1975, when detectable amounts of asbestos were found in the RCW. From August 1976 through may 1979, fiber counts varied from below detectable limits (0.7 x 106 fibers/liter) to 16.2 x 106 fibers/liter in the cooling tower water. These results were nearly identical to the initial asbestos fiber data obtained for RCW from December 1975 through July 1976. From January 1977 through May 1979, water samples from the X-616 Chromate Recovery Facility effluent and the X-611 Water Treatment Plant (RCW makeup) were also analyzed for asbestos, and fiber counts varied from below detectable limits to 0.7 x 106 fibers; liter and 1.4 x 106 fibers/liter, respectively. The number of fibers in the RCW system and at the X-611 and X-616 facilities does not present an environmental problem at this time. Beginning in June 1978, all samples collected were prepared for analysis by two methods after a United States Environmental Protection Agency-sponsored study demonstrated that a method different from the one used at Goodyear Atomic Corporation had essentially zero fiber losses. To date, no significant differences have been observed between the two methods. In the future, monitoring of asbestos fibers should continue on a periodic basis to determine if an asbestos fiber problem develops.Both methods of sample preparation should be utilizeds of sample preparation should be utilized to firmly establish which method is best
Adaptation of amoebae to cooling tower biocides.
Srikanth, S; Berk, S G
Adaptation of amoebae to four cooling tower Biocides, which included a thiocarbamate compound, tributyltin neodecanoate mixed with quaternary ammonium compounds (TBT/QAC), another QAC alone, and an isothiazolin derivative, was studied. Previously we found that amoebae isolated from waters of cooling towers were more resistant to cooling tower biocides than amoebae from other habitats. Acanthamoeba hatchetti and Cochliopodium bilimbosum, obtained from American Type Culture Collection and used in the previous studies, were tested to determine whether they could adapt to cooling tower Biocides. A. hatchetti was preexposed to subinhibitory concentrations of the four Biocides for 72h, after which they were tested for their resistance to the same and other biocides. C. bilimbosum was exposed to only two biocides, as exposure to the other two was lethal after 72 h. Preexposure to the subinhibitory concentrations of the Biocides increased the resistance of the amoebae, as indicated by a significant increase in the minimum inhibitory concentration (up to 30-fold). In addition, cross-resistance was also observed, i.e., exposure to one biocide caused resistance to other biocides. These results show that amoebae can adapt to biocides in a short time. The phenomenon of cross-resistance indicates that regularly alternating biocides, as is done to control microbial growth in cooling towers, may not be effective in keeping amoeba populations in check. On the contrary, exposure to one biocide may boost the amoebae's resistance to a second biocide before the second biocide is used in the cooling tower. Since amoebae may harbor Legionella, or alone cause human diseases, these results may be important in designing effective strategies for controlling pathogens in cooling towers. PMID:24190342
Energy Technology Data Exchange (ETDEWEB)
Brigmon, R.; Leskinen, S.; Kearns, E.; Jones, W.; Miller, R.; Betivas, C.; Kingsley, M.; Lim, D.
Detection of Legionella pneumophila in cooling towers and domestic hot water systems involves concentration by centrifugation or membrane filtration prior to inoculation onto growth media or analysis using techniques such as PCR or immunoassays. The Portable Multi-use Automated Concentration System (PMACS) was designed for concentrating microorganisms from large volumes of water in the field and was assessed for enhancing surveillance of L. pneumophila at the Savannah River Site, SC. PMACS samples (100 L; n = 28) were collected from six towers between August 2010 and April 2011 with grab samples (500 ml; n = 56) being collected before and after each PMACS sample. All samples were analyzed for the presence of L. pneumophila by direct fluorescence immunoassay (DFA) using FITC-labeled monoclonal antibodies targeting serogroups 1, 2, 4 and 6. QPCR was utilized for detection of Legionella spp. in the same samples. Counts of L. pneumophila from DFA and of Legionella spp. from qPCR were normalized to cells/L tower water. Concentrations were similar between grab and PMACS samples collected throughout the study by DFA analysis (P = 0.4461; repeated measures ANOVA). The same trend was observed with qPCR. However, PMACS concentration proved advantageous over membrane filtration by providing larger volume, more representative samples of the cooling tower environment, which led to reduced variability among sampling events and increasing the probability of detection of low level targets. These data highlight the utility of the PMACS for enhanced surveillance of L. pneumophila by providing improved sampling of the cooling tower environment.
Atmospheric emissions from power plant cooling towers
International Nuclear Information System (INIS)
Power plant recirculated cooling systems (cooling towers) are not typically thought of as potential sources of air pollution. However, atmospheric emissions can be important considerations that may influence cooling tower design and operation. This paper discusses relevant U.S. environmental regulations for potential atmospheric pollutants from power plant cooling towers, and various methods for estimating and controlling these emissions. (orig.)
Application of Response Surface Methodology (RSM for Optimization of Operating Parameters and Performance Evaluation of Cooling Tower Cold Water Temperature
Directory of Open Access Journals (Sweden)
Ramkumar RAMAKRISHNAN
Full Text Available The performance of a cooling tower was analyzed with various operating parameters tofind the minimum cold water temperature. In this study, optimization of operating parameters wasinvestigated. An experimental design was carried out based on central composite design (CCD withresponse surface methodology (RSM. This paper presents optimum operating parameters and theminimum cold water temperature using the RSM method. The RSM was used to evaluate the effectsof operating variables and their interaction towards the attainment of their optimum conditions.Based on the analysis, air flow, hot water temperature and packing height were high significanteffect on cold water temperature. The optimum operating parameters were predicted using the RSMmethod and confirmed through experiment.
Legionella detection and subgrouping in water air-conditioning cooling tower systems in Kuwait.
Al-Matawah, Qadreyah; Al-Zenki, Sameer; Al-Azmi, Ahmad; Al-Waalan, Tahani; Al-Salameen, Fadila; Hejji, Ahmad Ben
The main aim of the study was to test for the presence of Legionnaires' disease-causing microorganisms in air-conditioned buildings in Kuwait using molecular technologies. For this purpose, 547 samples were collected from 38 cooling towers for the analysis of Legionella pneumophila. These samples included those from water (n?=?178), air (n?=?231), and swabs (n?=?138). Out of the 547 samples, 226 (41�%) samples were presumptive positive for L. pneumophila, with L. pneumophila viable counts in the positive water samples ranging from 1 to 88�CFU/ml. Of the Legionella culture-positive samples, 204 isolates were examined by latex agglutination. These isolates were predominately identified as L. pneumophila serogroup (sg) 2-14. Using the Dresden panel of monoclonal antibodies, 74 representatives isolates were further serogrouped. Results showed that 51�% of the isolates belonged to serogroup 7 followed by 1 (18 %) and 3 (18�%). Serogroups 4 (4 %) and 10 (7�%) were isolated at a lower frequency, and two isolates could not be assigned to a serogroup. These results indicate the wide prevalence of L. pneumophila serogroup 7 as the predominant serogroup at the selected sampling sites. Furthermore, the 74 L. pneumophila (sg1?=?13; sg3?=?13; sg4?=?3; sg7?=?38; sg10?=?5; sgX?=?2) isolates were genotyped using the seven gene protocol sequence-based typing (SBT) scheme developed by the European Working Group for Legionella Infections (EWGLI). The results show that Legionella isolates were discriminated into nine distinct sequence typing (ST) profiles, five of which were new to the SBT database of EWGLI. Additionally, all of the ST1 serogroup 1 isolates were of the OLDA/Oxford subgroup. These baseline data will form the basis for the development of a Legionella environmental surveillance program and used for future epidemiological investigations. PMID:25701245
Physical parameters of effluent from nuclear power station cooling towers
International Nuclear Information System (INIS)
Physical parameters of the effluent dispersed from the wet cooling towers, i.e. mixture of the warm moist air with the entrained droplets are analysed. Understanding of the effluent physical parameters at the exit of cooling tower is important for prediction of the effluent dispersion in the environment. Mass and droplet diameter distributors of the drifted cooling water are measured in situ and also, drift eliminators are characterised experimentally. A new numerical method for heat and mass transfer evaluation in the cooling tower packing (fill) was developed, that leads to more accurate prediction for outlet air parameters in relation of plant power rate, cooling tower characteristics and atmospheric conditions. (author)
Upgrading the seismic performance of the interior water pipe supporting system of a cooling tower
International Nuclear Information System (INIS)
This paper presents results from a numerical study that was performed in order to simulate the seismic behavior of the interior support system of the piping and cooling features of a cooling tower in one of the old power stations located in an area at the North-Western part of Greece. This cooling tower has a diameter of 60 m and a height of 100 m. The interior piping support system consists mainly of a series of nine-meter high pre-cast vertical columns made by pre-stressed concrete; these columns, together with reinforced concrete pre-cast horizontal beams that are joined monolithically with the columns at their top, form the old interior supporting system. This system represented a very flexible structure, a fact that was verified from a preliminary numerical analysis of its seismic behavior. The maximum response to the design earthquake levels resulted in large horizontal displacements at the top of the columns as well as overstress to some of the columns. The most important part of the current numerical investigation was to examine various strengthening schemes of the old interior support system and to select one that will demonstrate acceptable seismic behavior. (authors)
Energy Technology Data Exchange (ETDEWEB)
Lee, S; Alfred Garrett, A; James02 Bollinger, J; Larry Koffman, L
Industrial processes use mechanical draft cooling towers (MDCT's) to dissipate waste heat by transferring heat from water to air via evaporative cooling, which causes air humidification. The Savannah River Site (SRS) has cross-flow and counter-current MDCT's consisting of four independent compartments called cells. Each cell has its own fan to help maximize heat transfer between ambient air and circulated water. The primary objective of the work is to simulate the cooling tower performance for the counter-current cooling tower and to conduct a parametric study under different fan speeds and ambient air conditions. The Savannah River National Laboratory (SRNL) developed a computational fluid dynamics (CFD) model and performed the benchmarking analysis against the integral measurement results to accomplish the objective. The model uses three-dimensional steady-state momentum, continuity equations, air-vapor species balance equation, and two-equation turbulence as the basic governing equations. It was assumed that vapor phase is always transported by the continuous air phase with no slip velocity. In this case, water droplet component was considered as discrete phase for the interfacial heat and mass transfer via Lagrangian approach. Thus, the air-vapor mixture model with discrete water droplet phase is used for the analysis. A series of parametric calculations was performed to investigate the impact of wind speeds and ambient conditions on the thermal performance of the cooling tower when fans were operating and when they were turned off. The model was also benchmarked against the literature data and the SRS integral test results for key parameters such as air temperature and humidity at the tower exit and water temperature for given ambient conditions. Detailed results will be published here.
The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor.
Minno?, Bihter; Ilhan-Sungur, Esra; �otuk, Ay??n; G�ng�r, Nihal Do?ru�z; Cansever, Nurhan
The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3 months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p < 0.01 and p < 0.01). PMID:23439037
Dynamic interaction effects in cooling tower groups
International Nuclear Information System (INIS)
A theoretical and experimental determination of the dynamic response of reinforced concrete cooling towers, taking into consideration group effects, are described. The results for an individual tower are thoroughly examined. A complete analysis is then performed for the critical wind orientations, for each tower in a six towers group. It's shown that ignoring group effects in the analysis may lead to a significant underestimation of the structural response. (E.G.)
Possible cooling tower designs and their economy
International Nuclear Information System (INIS)
The supporting shells of natural-draught cooling towers make very high demands on calculation and construction. Of the possible constructions, reinforced-concrete cooling towers constructed with the aid of climbing forms are the only ones which appear to be functional and economical. THe choice of the meridian curve of the cooling tower shell, which may be a hyperboloid of revolution or, in a more recent construction, of bell shape, is of great importance. In very large cooling towers, bracing rings cannot be dispensed with, as they improve the buckling and vibrational behaviour of the shell. This type of construction is also more economical than cooling tower shell with continuously varying shell thickness. (orig.)
The effects of natural winds on cooling towers
International Nuclear Information System (INIS)
Natural winds can affect both the thermal performance and structural design of cooling towers. From the thermal performance viewpoint the severity of wind effects is dependent upon the type of cooling tower being considered. In general, natural winds can cause stripping of falling water near the peripherary of the air inlet, reversal of the airflow into the tower and changes in the recooled water temperature. In the context of C.E.G.B. experience, these effects will be discussed with particular regard to remedial measures and predictive methods. From the structural design viewpoint the effects of natural winds are very important. It has been established that the shells of cooling towers vibrate at their resonant frequencies due to the turbulent nature of the incident wind. Consequently, in evaluating the wind induced stresses in cooling tower shells, it is essential to consider not only the static and quasi-static response of the shell but also its resonant response. As the fluctuating wind loading distribution on the surface of a cooling tower on a particular site cannot be defined explicitly at this time, it is necessary to evaluate wind induced stresses in a shell of a proposed design using wind tunnel test results appropriate to the site under consideration. The development of these wind tunnel test techniques and the results obtained for a typical C.E.G.B. cooling tower installation will be discussed
Causes and control of cooling tower film fill deposits
International Nuclear Information System (INIS)
Plastic film-type cooling tower fill material is used throughout the utility industry because of its excellent cooling capabilities, compact design, and durability. The remarkable heat rejection of these so-called high efficiency fill materials is due to its ability to form a film of water on a tremendous surface area. For example, hot (80-100 degrees F) recirculating water that is distributed over the cooling tower can be cooled up to 30 degrees with only a 3-4 feet depth of this fill material. By contrast, conventional splash bar cooling tower fill acts by forming droplets can require a volume many times that of film fill to achieve the same drop in cooling water temperature. This paper reports that over the past several years, the utility industry has learned that these high efficiency cooling tower fill materials are subject to fouling, despite the manufacturer or subtle differences in fill design. With certain types of makeup water quality and tower operating practices, it is sometimes impossible to avoid fouling the fill without chemical treatments to control the progression of deposit formation
Secondary motions in a cooling tower plume
International Nuclear Information System (INIS)
Time-lapse photography was used to estimate the speed of the vortex in the condensed plume at the edge of a bank of mechanical draft cooling towers at the Oak Ridge Gaseous Diffusion Plant. At a distance of about 30 m from the towers, the median tangential speed is about 2 m/s in the downward direction
Dry cooling tower operating experience in the LOFT reactor
International Nuclear Information System (INIS)
A dry cooling tower has been uniquely utilized to dissipate heat generated in a small experimental pressurized water nuclear reactor. Operational experience revealed that dry cooling towers can be intermittently operated with minimal wind susceptibility and water hammer occurrences by cooling potential steam sources after a reactor scram, by isolating idle tubes from the external atmosphere, and by operating at relatively high pressures. Operating experience has also revealed that tube freezing can be minimized by incorporating the proper heating and heat loss prevention features
Calculating the evaporated water flow in a wet cooling tower; Le calcul du debit d`eau evaporee dans un aerorefrigerant humide
Energy Technology Data Exchange (ETDEWEB)
Grange, J.L.
On a cooling tower, it is necessary to determine the evaporated water flow in order to estimate the water consumption with a good accuracy according to the atmospheric conditions, and in order to know the characteristics of the plume. The evaporated flow is small compared to the circulating flow. A direct measurement is very inaccurate and cannot be used. Only calculation can give a satisfactory valuation. The two usable theories are the Merkel`s one in which there are some simplifying assumptions, and the Poppe`s one which is more exact. Both theories are used in the numerical code TEFERI which has been developed and is run by Electricite de France. The results obtained by each method are compared and validated by measurements made in the hot air of a cooling tower. The consequences of each hypothesis of Merkel`s theory are discussed. This theory does not give the liquid water content in the plume and it under-estimates the evaporated flow all the lower the ambient temperature is. On the other hand, the Poppe`s method agrees very closely with the measurements as well for the evaporated flow than for the liquid water concentration. This method is used to establish the specific consumption curves of the great nuclear plants cooling towers as well as to calculate the emission of liquid water drops in the plumes. (author). 11 refs., 9 figs.
Design of SMART waste heat removal dry cooling tower using solar energy
International Nuclear Information System (INIS)
The 85% of cooling system are once-through cooling system and closed cycle wet cooling system. However, many countries are trying to reduce the power plant water requirement due to the water shortage and water pollution. Dry cooling system is investigated for water saving advantage. There are two dry cooling system which are direct and indirect cooling system. In direct type, turbine exhaust is directly cooled by air-cooled condenser. In indirect system, turbine steam is cooled by recirculating intermediate cooling water loop, then the loop is cooled by air-cooled heat exchanger in cooling tower. In this paper, the purpose is to remove SMART waste heat, 200MW by using newly designed tower. The possibility of enhancing cooling performance by solar energy is analyzed. The simple cooling tower and solar energy cooling tower are presented and two design should meet the purpose of removing SMART waste heat, 200MW. In first design, when tower diameter is 70m, the height of tower should be 360m high. In second design, the chimney height decrease from 360m to 180m as collector radius increase from 100m to 500m due to collector temperature enhancement by solar energy, To analyze solar cooling tower further, consideration of solar energy performance at night should be analyzed
Response of cooling towers to wind loads
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G. Murali
Full Text Available This paper deals with the study of two cooling towers of 122 m and 200 m high above ground level. These cooling towers have been analysed for wind loads using ANSYS software by assuming fixity at the shell base. The wind loads on these cooling towers have been calculated in the form of pressures by using the circumferentially distributed design wind pressure coefficients as given in IS: 11504 - 1985 code [1] along with the design wind pressures at different levels as per IS:875 (Part 3 - 1987 code [2]. The analysis has been carried out using 8-noded shell element (SHELL 93 with 5 degrees of freedom per node. The results of the analysis include membrane forces, viz., meridional force (Nf and hoop force (Nq, and bending moments, viz., meridional moment (Mf and hoop moment (Mq. The vertical distribution of membrane forces and bending moments along 0o and 70o meridians and the circumferential distributions at base, throat and top levels have been studied for both the cooling towers. For circumferential distribution, non-dimensional values have been obtained by normalizing the membrane forces and bending moments using the reference values at 0o meridian. Similarly, the reference values at the base have been used for vertical distribution. These non-dimensional curves for both the cooling towers have been compared in the present study for the feasibility of any generalisation.
Structure of natural draft cooling towers, 1
International Nuclear Information System (INIS)
Thousands of natural draft cooling towers have been utilized, in Europe and America, as cooling systems of power plants or as countermeasures against thermal polution. Recently in Japan, demands for cooling tower systems have been increasing remarkably with the construction of large power plants and the legislation of environmental regulations. In view of the severe natural conditions in Japan such as strong wind and seismic loadings, etc., the establishment of the optimum design and construction method is essential for the building of safe and economical towers. In order to establish a comprehensive plan of a power plant cooling system of the appropriate structural type, the authors have made researches and experiments on design conditions, static and dynamic analyses, and comparative studies of various structural types such as reinforced concrete thin-shell structures, steel framed structures and composite shell segment structures, based on the investigation results of towers in Europe and America. These results are presented in three reports, the 1st of which concerns cooling tower shells as are hereinafter described. (auth.)
Improvement of coal focus and cooling towers of COFRENTES NPP
International Nuclear Information System (INIS)
Cofrentes Nuclear Power Plant is performing a improving program of its cooling towers based on the filling revamping and cooling water circuit improvement. Furthermore, and as consequence of the acquired experience on cooling towers due to the mentioned program, Cofrentes NPP has decided to follow up with this project from a different point of view based on the thermal-hydraulic optimization of the cooling process inside the towers. This program, which is going to be carried out by Cofrentes NPP, Iberinco and Energy Planning and Power Generation (EPPG) provides an improvement on the thermal profile and of the draught inside the cooling towers by improving the water distribution in the towers active area. In order to perform such a program is needed to fulfill a test program to assure a guaranteed performance gain. In this way, Iberinco is developing a test procedure which improves the results which are obtained with the present standards used commonly by the industry. As a consequence of this program, Cofrentes is expecting to obtain a gain of 5 to 8 MWe with a revenue period of 4 to 5 months, results validated in another foreigner Plant which have developed a similar program. (Author)
Wet/dry cooling tower and method
Glicksman, Leon R. (Lynnfield, MA); Rohsenow, Warren R. (Waban, MA)
A wet/dry cooling tower wherein a liquid to-be-cooled is flowed along channels of a corrugated open surface or the like, which surface is swept by cooling air. The amount of the surface covered by the liquid is kept small compared to the dry part thereof so that said dry part acts as a fin for the wet part for heat dissipation.
Universal Engineering Model for Cooling Towers
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Mohd Arif
Full Text Available This paper presents a universal engineering model, which can be used to formulates both counter-flow and cross-flow cooling towers. By using fundamental laws of mass and energy balance, the effectiveness of heat exchange is approximated by a second order polynomial equation. Gauss -Newton and Levenberg-Marquardt methods are then used to determine the coefficients from manufactures data. Compared with the existing models, the new model has two main advantages: (1 As the engineering model is derived from engineering perspective, it involves fewer input variables and has better description of the cooling tower operation; (2 There is no iterative computation required, this feature is very important for online optimization of cooling tower performance. Although the model is simple, the results are very accurate. Application examples are given to compare the proposed model with commonly used models.
Hybrid cooling towers in economic comparison with wet and dry cooling towers
International Nuclear Information System (INIS)
The hybrid cooling tower for Unit 5 at the Neckarwerke Electricity Supply Company, a bituminuous coal-fired unit with an installed capacity of 465 MW, erected in Altbach/Deizisau under a contract with the Neckar Heating Power Station Company, has been in operation since the middle of 1985 with a waste heat capacity of 558 MW. In the meantime the cooling tower has not only met the requirements imposed on it but has also permitted vapour plume-free operation on days with low atmospheric temperature - which has occurred more often than forecasted. Another cooling tower of the same design is currently being erected for the second unit of the Neckar Community Nuclear Power Station Company (GKN) at Neckarwestheim, 1300 MW 'convoy' unit. Its waste heat capacity is about 4.5 times as great. Using this cooling tower as an example an economic comparison is made with the natural draught cooling tower and with the dry cooling tower. The comparison led to the result that the hybrid cooling tower can be offered as a solution in special cases for future new power station construction and for retrofit installations. (orig.)
Study of modes of operation water system movement with bypass system towers cooling by Ecosimpro
International Nuclear Information System (INIS)
The present paper is based on the thermodynamic study of the system of water circulation of the Central Nuclear de Cofrentes. The objective of the study is the operation of the system through different modes of operation, with the aim of analyze the impact of these modes over the operation of the same. For a complete analysis, it has created a computer model of the system through the EcosimPro software, which is the simulation of the operation modes system and through the results, is the analysis of their feasibility.
The water-saving and environmentally-minded utilization of waste heat as a substitute for cooling towers-Agrotherm
International Nuclear Information System (INIS)
Since 1976 the conditions for the utilization of waste heat from power plants in agriculture has been investigated in different test plants in the F.R. of Germany. The system 'Agrotherm' is to substitute traditional cooling towers by closed underground pipe networks. The various investigations showed an overall increase of yield and premature harvest on acreages which had been heated by such pipe networks. The reactions of the various agricultures differ very much, so that a careful choice of sorts is necessary. Possibly considerable infestations of diseases must be expected. The article gives a summary of the most important results gained from the test plants. (KH)
A study of a desuperheater heat recovery system complete with a reversibly used water cooling tower (RUWCT) for hot water supply
Tan, Kunxiong
Recovering heat rejected from the condenser in a refrigeration system to generate service hot water for buildings is commonly seen in both tropics and subtropics. This study included a critical literature review on heat recovery from air-conditioning/refrigeration systems, with particular emphasis on the direct condenser heat recovery and its related mathematical simulation models. The review identified many applications of desuperheaters to small-scaled residential air-conditioning or heat pump units. The heat and mass transfer characteristics of a RUWCT have been studied in detail, which is based on the theory of direct contact heat and mass transfer between moist air and water. The thesis reports on the differences in the heat and mass transfer process that takes place in a RUWCT, a standard water cooling tower and a spray room. A corrective factor that accounts for the change of chilled water mass flow rate is incorporated into the theoretical analysis of a RUWCT. The algorithms developed from the theoretical analysis are capable of predicting the heat exchange capacity of a RUWCT at any operating conditions. This theoretical analysis is the first of its kind. Extensive field experimental work on the heat and mass transfer characteristics of a RUWCT has been carried out in a hotel building in Haikou, Hainan province of China, where the RUWCT is installed. Results from the experimental work indicate that the theoretical analysis can represent the heat and mass transfer characteristics in a RUWCT with an acceptable accuracy. A numerical analysis for a RUWCT is undertaken to determine both air and water states at intermediate horizontal sections along the tower height. Field experimental data confirm that the predicted air and water conditions at the tower inlet and outlet are of acceptable accuracy. A steady-state mathematical model is developed to simulate the operational performance of a water chiller plant complete with a desuperheater heat recovery system and a RUWCT. This model will be useful in future studies on the optimum design of a water chiller complete with a desuperheater and a RUWCT for heat recovery. (Abstract shortened by UMI.)
Cooling tower windage: a new aspect to environmental assessment
International Nuclear Information System (INIS)
Results of the several investigations provided quantitative estimates of windage from Oak Ridge Gaseous Diffusion Plant cooling towers. Windage water deposited on the ground has the potential to reach nearby streams through runoff. Windage deposited on moisture depleted soils would not be significant. During winter months at Oak Ridge soils generally have a high moisture content such that windage deposition could be quickly transported as runoff. It is during this time that cooling towers are sometimes operated without fan-induced draft. Since windage water contains the same hexavalent chromium concentration (9 ppM) as the recirculating cooling water system, the runoff stream from the K-892J tower constitues a NPDES violation as an unpermitted discharge. As a long-term abatement strategy, concrete aprons were constructed along each side of new cooling towers at the Paducah, Kentucky Gaseous Diffusion Plant. The maximum distance of windage impact is wind dependent. If apron construction is envisioned as an abatement strategy at Oak Ridge, the maximum distance of impact can be inferred graphically from the several points where windage (fans off) and drift (fans on) loss curves intersect under the different meteorological conditions. Once the hexavalent chromium laden runoff stream reaches Poplar Creek, it is diluted well below the standards for drinking water and poses little potential for biological effects to aquatic systems
Piers cooling towers. From first idess to realizations
International Nuclear Information System (INIS)
After a first part consecrated at the historical aspect of vertical piers cooling towers the second part indicates the experience pulled of the Chooz and Golfech cooling towers conception and realization
Modeling of existing cooling towers in ASPEN PLUS using an equilibrium stage method
International Nuclear Information System (INIS)
Highlights: ? Simulation of cooling tower performance under different operating conditions. ? Cooling tower performance is simulated using ASPEN PLUS. ? Levenberg�Marquardt method used to adjust model parameters. ? Air and water outlet temperatures are in good accordance with experimental data. - Abstract: Simulation of cooling tower performance considering operating conditions away from design is typically based on the geometrical parameters provided by the cooling tower vendor, which are often unavailable or outdated. In this paper a different approach for cooling tower modeling based on equilibrium stages and Murphree efficiencies to describe heat and mass transfer is presented. This approach is validated with published data and with data collected from an industrial application. Cooling tower performance is simulated using ASPEN PLUS. Murphree stage efficiency values for the process simulator model were optimized by minimizing the squared difference between the experimental and calculated data using the Levenberg�Marquardt method. The minimization algorithm was implemented in Microsoft Excel with Visual Basic for Applications, integrated with the process simulator (ASPEN PLUS) using Aspen Simulation Workbook. The simulated cooling tower air and water outlet temperatures are in good accordance with experimental data when applying only the outlet water temperature to calibrate the model. The methodology is accurate for simulating cooling towers at differating cooling towers at different operational conditions.
Electrocoagulation to Remove Silica from Cooling Towers Water / Electrocoagulaci�n para remover s�lice en agua de torres de enfriamiento
Scientific Electronic Library Online (English)
Iv�n Emmanuel, Villegas-Mendoza; Alejandra, Mart�n-Dom�nguez; Sara, P�rez-Castrej�n; Silvia Lucila, Gelover-Santiago.
Full Text Available El presente art�culo muestra los resultados de un estudio que se llev� a cabo para evaluar el efecto de la calidad del agua en la remoci�n de s�lice disuelto mediante un proceso de electrocoagulaci�n utilizando electrodos de aluminio. El s�lice se encuentra en el agua de repuesto (RW) y de purga de [...] las torres de enfriamiento (CTBW). Las pruebas se hicieron a escala semipiloto a flujo continuo en un tren de tratamiento consistente de electrocoagulaci�n (EC), floculaci�n, sedimentaci�n y filtraci�n en arena. Se estudiaron dos RW y CTBW, con caracter�sticas fisicoqu�micas diferentes. Las variables de respuesta analizadas fueron las siguientes: eficiencia del aluminio para remover s�lice (relaci�n mgl-1 de Al3+ dosificado/mgl-1 de s�lice removido), eficiencia de remoci�n de Al3+ dosificado, p�rdida de carga hidr�ulica a trav�s del reactor electroqu�mico y el voltaje. Se calcul� el costo del tratamiento de los cuatro tipos de agua. La relaci�n mgl-1 de Al3+ dosificado/mgl-1 de s�lice removido oscil� de 1.09 � 0.06 a 1.33 � 0.05 al tratar RW, mientras que para CTBW fue de 0.85 � 0.1. Los costos de energ�a, sustancias qu�micas y consumo de electrodos para el tratamiento de RW oscil� de US$ 0.52 a US$ 0.74 m-3, y el costo del tratamiento de CTBW fue de aproximadamente US$ 0.53 m-3. Abstract in english This paper presents the results of a study carried out about the effect of water quality on the removal of dissolved silica using an electrocoagulation process with aluminum electrodes. Silica is found in replacement water (RW), usually known as make up water, and in cooling tower blowdown water (CT [...] BW). Tests were conducted on a small pilot scale (~2 lmin-1) with a continuous flow device. The treatment train consisted of electrocoagulation (EC), flocculation, sedimentation and sand filtration. Two distinct RW and two CTBW with different physicochemical characteristics were studied. The response variables analyzed were: efficiency of aluminum to remove silica (ratio mgl-1 of dosed Al3+/mgl-1 SiO2 removed), removal efficiency of dosed Al3+, hydraulic head loss throughout the electrochemical reactor and voltage. The cost of the treatment for the four types of water is discussed. The ratio mgl-1 Al3+ dosed /mgl-1 silica removed ranged from 1.09 � 0.06 to 1.33 � 0.05 when treating RW and 0.85 � 0.1 when treating CTBW. The consumption costs of energy, chemicals and electrodes for RW treatment ranged from US$ 0.52 to 0.74 m-3, and was approximately US$0.53 m-3 for CTBW.
Design problems of large wet cooling towers
International Nuclear Information System (INIS)
This article aims to indicate the situation which initiated the 'investigations into a natural-draught wet cooling tower' from the VDI progress report 15/5. At the time, the electricity utilities were surprised by the condition, in connection with the building of new power plants on the Rhine, to provide river-independent cooling systems. This condition has not merely enlarged the site criteria catalogue extensively, but also demanded the introduction of a new cooling technology on this scale in the southern regions of the Federal Republic of Germany. (orig./LH)
Corrosion control studies in a mini cooling tower
International Nuclear Information System (INIS)
Generally, raw water is used for cooling the condensers in packaged air conditioning (AC) units installed in separate buildings. These AC units and their cooling water systems are operated on as-and-when required basis. The cooling water remains untreated generally. The Fast Breeder Test Reactor (FBTR) at Kalpakkam, TamiInadu, India is a 40 MWt sodium cooled, (uranium and plutonium) mixed carbide fuelled nuclear test reactor. In FBTR, four freon-based packaged AC units having 40 TR capacities with cooling water system have been installed in Annexe Building. Palar river water serves as the make-up to the system. The heat extracted from condensers is rejected in natural draft cooling tower. Initially, algae fouling and increased corrosion attacks were observed in the system. Sodium hypo chlorite dosing reduced the algae fouling considerably. Corrosion monitoring program was initiated with installation of corrosion monitoring set up. Inhibitors and dispersants like hydroxy ethylidene diphosphonic acid, sodium hexa meta phosphate, sodium dodecyl sulphate, ortho phosphoric acid and poly acrylic acid were used. It has been observed that minimum corrosion rate of 5 mpy could be obtained with 20 ppm of Hydroxy Ethylidene Diphosphonic Acid (HEDP) and 20 ppm of poly acrylic acid as against 9 mpy for the untreated water. This paper describes the problems associated with irregular operation of cooling water systems in corrosion control and experience gained in control of bio fould experience gained in control of bio fouling and corrosion in cooling water system installed in packaged AC units having natural draft cooling tower. (author)
Analysis of the evaporative towers cooling system of a coal-fired power plant
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Lakovi? Mirjana S.
Full Text Available The paper presents a theoretical analysis of the cooling system of a 110 MW coal-fired power plant located in central Serbia, where eight evaporative towers cool down the plant. An updated research on the evaporative tower cooling system has been carried out to show the theoretical analysis of the tower heat and mass balance, taking into account the sensible and latent heat exchanged during the processes which occur inside these towers. Power plants which are using wet cooling towers for cooling condenser cooling water have higher design temperature of cooling water, thus the designed condensing pressure is higher compared to plants with a once-through cooling system. Daily and seasonal changes further deteriorate energy efficiency of these plants, so it can be concluded that these plants have up to 5% less efficiency compared to systems with once-through cooling. The whole analysis permitted to evaluate the optimal conditions, as far as the operation of the towers is concerned, and to suggest an improvement of the plant. Since plant energy efficiency improvement has become a quite common issue today, the evaluation of the cooling system operation was conducted under the hypothesis of an increase in the plant overall energy efficiency due to low cost improvement in cooling tower system.
Measurements on cooling tower plumes. Pt. 3
International Nuclear Information System (INIS)
In this paper an extended field experiment is described in which cooling tower plumes were investigated by means of three-dimensional in situ measurements. The goal of this program was to obtain input data for numerical models of cooling tower plumes. Data for testing or developing assumptions for sub-grid parametrizations were of special interest. Utilizing modern systems for high-resolution aerology and small aircraft, four measuring campaigns were conducted: two campaigns (1974) at the cooling towers of the RWE power station at Neurath and also two (1975) at the single cooling tower of the RWE power station at Meppen. Because of the broad spectrum of weather situations, it can be assumed that the results are representative with regard to the interrelationship between the structure of cooling tower plumes and the large-scale meteorological situation. A large number of flights with a powered glider ASK 16 (more than 100 flight hours) crossing the plumes on orthogonal tracks was performed. All flights showed that the plume could be identified up to large downwind distances by discontinuous jumps of temperature and vapour pressure. Therefore a definite geometry of the plume could always be defined. In all cross sections a vertical circulation could be observed. At the plumes boundaries, which could be defined by the mentioned jumps of temperature and vapour pressure, a maximum of downward vertical motion was observed in most cases. Entrainment along the boundary of a cross section seems to be very small, except at the lower part of the plume. There, the mass entrainment is maximum and is responsible for plume rise as well as for enlargement of the cross section. The visible part of the plume (cloud) was only a small fraction of the whole plume. The discontinuities of temperature and vapour pressure show that the plume fills the space below the visible plume down to the ground. However, all effects decrease rapidly towards the ground. It turned out that high-resolution aerology is necessary in order to explain the structure and behaviour of such plumes. This is especially the case in investigations regarding the dynamic break-through of temperature inversions. Such cases were observed quite frequently under various meteorological conditions and are described in this paper. (orig.)
Device for noise-abatement in a cooling tower
International Nuclear Information System (INIS)
This device attenuates the noise of cooling water droplets falling out of trickling plates below a spray facility. In this manner expensive noise-attenuating cranks or embankments around the cooling tower become unnecessary. Noise attenuation is achieved by a catching device closely above the water reservoir. Instead of falling vertically on the water surface, the droplets hit the inclined surfaces of a horizontal grid. A number of such plane or slightly curved surfaces are placed together with little inclination against the vertical (250 to 300, with a maximum of 450) at such a distance that no drop can hit the water surface directly, i.e. unattenuated. In a second type of design also the capacity of the cooling water pumps and with it the investment and operating cost is reduced. For instance, about 2000 kW are saved by higher arrangement of the catching device, closely below the trickling components. (RW)
Effect of chlorine and temperature on free-living protozoa in operational man-made water systems (cooling towers and hot sanitary water systems) in Catalonia.
Canals, Oriol; Serrano-Su�rez, Alejandra; Salvad�, Humbert; M�ndez, Javier; Cervero-Arag�, S�lvia; Ruiz de Porras, Vicen�; Dellund�, Jordi; Araujo, Rosa
In recent decades, free-living protozoa (FLP) have gained prominence as the focus of research studies due to their pathogenicity to humans and their close relationship with the survival and growth of pathogenic amoeba-resisting bacteria. In the present work, we studied the presence of FLP in operational man-made water systems, i.e. cooling towers (CT) and hot sanitary water systems (HSWS), related to a high risk of Legionella spp. outbreaks, as well as the effect of the biocides used, i.e. chlorine in CT and high temperature in HSWS, on FLP. In CT samples, high-chlorine concentrations (7.5?�?1.5�mg chlorine L(-1)) reduced the presence of FLP by 63.8�% compared to samples with low-chlorine concentrations (0.04?�?0.08�mg chlorine L(-1)). Flagellates and amoebae were observed in samples collected with a level of 8�mg chlorine L(-1), which would indicate that some FLP, including the free-living amoeba (FLA) Acanthamoeba spp., are resistant to the discontinuous chlorine disinfection method used in the CT studied. Regarding HSWS samples, the amount of FLP detected in high-temperatures samples (53.1?�?5.7��C) was 38�% lower than in low-temperature samples (27.8?�?5.8��C). The effect of high temperature on FLP was chiefly observed in the results obtained by the culture method, in which there was a clear reduction in the presence of FLP at temperatures higher than 50��C, but not in those obtained by PCR. The findings presented here show that the presence of FLP in operational man-made water systems should be taken into account in future regulations. PMID:25410311
Investigation of emissions of harmful substances in the cooling tower of the final coke oven gas cooling cycle
International Nuclear Information System (INIS)
It is known that the cooling tower of the open coke oven gas cooling cycle is the main source of emissions to the atmosphere of hydrogen cyanide. Desorption of volatile harmful substances in cooling tower depends on a large number of processing parameters and the compositions of the circulating water. The authors conducted a study of desorption of volatile components and a model of adequate scale of the final gas cooling cycle on an experimental industrial unit with a gas output of about 500 m3/hr. The unit was built at the Cherepovets Integrated Iron and Steel Works. In includes a cooling tower made of tubes 100 mm in diameter with a total height of about 5,100 mm. The volume of the lower part is 2.12 m3. Preliminary experimental evaluation of operation of the cooling tower according to the material and heat balances showed that it models operation of an industrial cooling tower quite well. Emissions of harmful substances in the cooling tower were determined by analyzing the circulating water and air before and after the cooling tower. Averaged samples for specified times were collected and the process parameters were simultaneously recorded (flow rates and temperatures of water and air), as well as the relative humidity and air pressure. Analysis of possible errors and the actual agreement of the determinations of the content of substances in air and water showed that evaluation of desorption of volatile components according to water analyses ie components according to water analyses is more reliable (this conclusion is especially valid for industrial cooling towers). Results are described
Stiffened cooling tower shells of reinforced concrete
International Nuclear Information System (INIS)
Presenting a kinetic method to derive the linear buckling and vibration problem of unstiffened and stiffened hyperboloidal cooling tower shells of reinforced concrete a parametric study is carried out using finite elements. The following parameters are varied: the type of axisymmetric load, the main geometric dimensions, the curvature of the meridional function and the type of stiffening, that means number, dimension and arrangement of meridional ribs and stiffening rings. The numerical results are interpreted. The tendencies recognizable are formulated and summarized in forme of recommendations. (orig.)
Studies of cooling tower components on the Mistral test bench
International Nuclear Information System (INIS)
The conception of a humid air cooling tower with natural or forced draught, requires the knowledge of the thermal and aerodynamic exchange surfaces performances. Several points, among which the distribution nozzles and drift eliminators efficiencies, or the mechanical behavior of the components, should be considered. In order to be able to test this type of equipment and analyse its behavior, ELECTRICITE DE FRANCE set up in 1987 of a large dimensions test bench: MISTRAL. The investigations performed over the 3000 working hours of MISTRAL concern mainly the optimization of the counterflow and crossflow exchange surfaces proposed by the industrial cooling tower equipment suppliers. The quality of the experimental results is assured by the implementation of an extensive instrumentation on the air and water circuits, and by a severe control of the tests conditions
Efficiency control in a commercial counter flow wet cooling tower
International Nuclear Information System (INIS)
This paper presents open and closed-loop analyses of a counter flow wet cooling tower. The closed-loop system analysis was based on a comparative evaluation of three control strategies. The first and second comprised a split-range control of the cooling water temperature and an index of thermal performance (efficiency), respectively, and the third strategy comprised a combination of override and split-range control in order to control two performance indexes (efficiency and effectiveness). In this case, a SISO (Single-Input Single-Output) loop for each controlled variable is considered. In each case the water loss through evaporation and the energy consumption in the cooling tower (pump and fans) were estimated in order to analyze its eco-efficiency. All the simulation tests were carried out considering the same regulatory problem and the results show a notable improvement in the tower's performance when compared to open-loop operation, thus attesting the potential benefits of the use of an efficient control strategy for such equipment.
Measurements at cooling tower plumes. Part 3. Three-dimensional measurements at cooling tower plumes
International Nuclear Information System (INIS)
An extended field experiment is described in which cooling tower plumes were studied by means of three-dimensional in situ measurements. The goal was to obtain input data for numerical models of cooling tower plumes. Of special interest were data for testing or developing assumptions for sub-grid parametrizations. Utilizing modern systems for high-resolution aerology and small aircraft, four measuring campaigns were conducted: two campaigns (1974) at the cooling towers of the RWE power station Neurath and also two (1975) at the single cooling tower of the RWE power station Meppen. Because of the broad spectrum of weather situations it can be assumed that the results are representative with regard to the interrelationship between structure of cooling tower plume and large-scale meteorological situation. A large number of flights with a powered glider crossing the plumes on orthogonal tracks was performed. All flights showed that the plume could be identified up to large downwind distances by discontinuous jumps of temperature and vapor pressure. Therefore, a definite geometry of the plume could always be defined. In all cross sections a vertical circulation could be observed. At the boundary, which could be defined by the mentioned jumps of temperature and vapor pressure, a maximum of downward vertical motion could be observed in most cases. Entrainment along the boundary of a cross section seems to be very small, except at the lower part of the plume. There, the mass entrainment is maximum and is responsible for plume rise as well as for enlargement of the cross section. The visible part of the plume (cloud) was only a small fraction of the whole plume. High-resolution aerology is necessary in order to explain the structure and behavior of such plumes. This is especially the case in investigations regarding the dynamic break-through of temperature inversions. Such cases were observed frequently under various meteorological conditions and are described
In this activity, learners explore how engineers work to solve the challenges of a society, such as delivering safe drinking water. Learners work in teams to devise a system using everyday materials that can deliver water in a controlled manner to a paper cup that is about 36 inches or 90 cm away. Learners sketch their plans, build their system, test it, and reflect on the challenge.
Thermal performance upgrade of the Arkansas Nuclear One cooling tower: A ''root cause'' analysis approach
International Nuclear Information System (INIS)
The thermal performance efficiency of the natural draft cooling tower at Entergy Operations' 858 MWe Arkansas Nuclear One, Unit 2 was successfully upgraded to 101% of design performance capability in April 1994 as the end result of a unique root-cause analysis of the cooling tower's long-standing performance deficiencies. Through application of state-of-the-art diagnostic testing methods and computer modeling techniques, Entergy was able to identify and correct air/water maldistribution problems in the 447 foot tall counterflow cooling tower at minimal cost. Entergy estimates that the savings realized, as a result of the 1.2 F reduction in cooling tower outlet water temperature, will pay for the thermal upgrade project in approximately 14 months
Design of a water tower in steel
Nicolaou, Irini
The main objective of this project is t? design a Water Tower in Steel for potable water. The Water Tower will be constructed to act as a water reservoir, in a water supply system. The size of the tank depends on the capacity of water to be stored. The cost of Water Tower depends mainly on its shape and on the type of structural material that is going to be used. In this project the Water Tower is made of Mild Steel, Grade 43. The choice of the shape was done, taking into account the di...
Discrete model-based operation of cooling tower based on statistical analysis
International Nuclear Information System (INIS)
Highlights: � We introduce an index to describe the cooling capability of a cooling tower. � The effect of ambient air on cooling capability is studied by statistics analysis. � Physical-meaningful and precise-enough model is built by actual operation data. � The application to a real cooling tower is promising for energy conservation. - Abstract: This study is aimed to utilize the operation data to build a physical-meaningful and precise-enough model to assist the operation of a cooling tower. To do so, this work introduces a dimensionless index, which can describe the cooling capability of a cooling tower in terms of effective power utilization. In the first phase of this study, principal component analysis, one of factor analysis methods, is used to investigate effects of ambient air temperature and relative humidity on the cooling capability of a cooling tower. Based on the proposed cooling capability index, the operation data are partitioned into different groups by the fuzzy c-mean clustering algorithm. The resulted groups are distinctly categorized by the conditions of ambient air temperature and relative humidity. In the second phase of the study, data within the same mode of a set of fans are partitioned by the fuzzy c-mean clustering algorithm. The resulted groups of data are then modeled by linear regression. The acquired multiple models are highly accurate in predicting the output temperature of cooling water from the cooling tower. The acquired models assist the operator to accurately select the proper fan mode when process conditions, e.g., cooling loading, or environment conditions, e.g., ambient air temperature, change. It results in electricity saving. This study is concluded by the presentation of a discrete model-based approach to determine the fan mode. The application to a real cooling tower in an iron and steel plant is promising in saving electricity consumed by the fan set
On the influence of psychrometric ambient conditions on cooling tower drift deposition
Lucas Mart�nez, Manuel; Ruiz Ram�rez, Javier; S�nchez Kaiser, Antonio; Viedma, A.; Mart�nez Beltr�n, Pedro Juan
Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health reasons. A numerical model to study the influence of sychrometric ambient conditions on cooling tower drift deposition was developed. The mathematical model presented, consisting of two coupled sets of conservation equations for the continuous and discrete phases, was incorporated in the general purpose CFD code Fluent. Both experimental plume performance and drift deposition were employed...
Experimental investigation of the hydraulic characteristics of a counter flow wet cooling tower
International Nuclear Information System (INIS)
Thermal and nuclear electric power plants as well as several industrial processes invariably discharge considerable energy to their surrounding by heat transfer. Although water drawn from a nearby river or lake can be employed to carry away this energy, cooling towers offer an excellent alternative particularly in locations where sufficient cooling water cannot be easily obtained from natural sources or where concern for the environment imposes some limits on the temperature at which cooling water can be returned to the surrounding. This paper concerns an experimental investigation of the hydraulic characteristics of a counter flow wet cooling tower. The tower contains a 'VGA.' (Vertical Grid Apparatus) type packing which is 0.42 m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross sectional test area of 0.15 m x 0.148 m. The present investigation is focused mainly on the effect of the air and water flow rates on the hydraulic characteristics of the cooling tower, for different inlet water temperatures. The two hydrodynamic operating regimes which were observed during the air/water contact operation within the tower, namely the Pellicular Regime (PR) and the Bubble and Dispersion Regime (BDR) have enabled to distinguish two different states of pressure drop characteristics. The first regime is characterized by low pressure drop values, while in the second regime, the pressure drop values are relatively much higher than those observed in the first one. The dependence between the pressure drop characteristics and the combined heat and mass transport (air-water) through the packing inside the cooling tower is also highlighted. The obtained results indicate that this type of tower possesses relatively good hydraulic characteristics. This leads to the saving of energy. -- Highlights: ? Cooling towers are widely used to reject waste heat from thermal and nuclear electric power plants to the atmosphere. ? The hydraulic characteristics of a counter flow wet cooling tower have been studied experimentally. ? The effect of the air and water flow rates on the hydraulic characteristics of tower was investigated. ? Different inlet water temperatures: 35 oC, 43 oC and 50 oC, respectivelly, were used in the investigation. ? The results indicate that this type of tower possesses relatively good hydraulic characteristics.
Safety analysis for K reactor and impact of cooling tower installation
International Nuclear Information System (INIS)
This paper describes the safety analysis of the Savannah River site K-reactor loss-of-cooling-water-supply (LOCWS) event and the impact on the analysis of a natural-draft cooling tower, which was installed in 1992. Historically (1954 to 1992), the K-reactor secondary cooling system [called the cooling water system (CWS)] used water from the Savannah River pumped to a 25-million-gal basin adjacent to the reactor. Approximately 170 000 gal/min were pumped from the basin through heat exchangers to remove heat from the primary cooling system. This water then entered a smaller basin, where it flowed over a weir and eventually returned to the Savannah River. The 25-million-gal basin is at a higher elevation than the heat exchangers and the smaller basin to supply cooling by gravity flow (which is sufficient to remove decay heat) if power to the CWS pumps is interrupted. Small amounts of cooling water are also used for other essential equipment such as diesels, motors, and oil coolers. With the cooling tower installed, ?85% of the cooling water flows from the small basin by gravity to the cooling tower instead of returning to the Savannah River. After being cooled, it is pumped back to the 25-million-gal basin. River water is supplied only to make up for evaporation and the blowdown stream
Numerical simulation of a cooling tower coupled with heat pump system associated with single house using TRNSYS
International Nuclear Information System (INIS)
Highlights: � We simulate a cooling tower coupled with heat pump system and a single zone using TRNSYS. � We examine the temperature of water inside the cooling tower and inside the single zone. � We study the temporal evolution of the all parameters for 4500 h operation in winter in Tunisia. - Abstract: The industrial cooling towers in Tunisia meet difficulties due to the poor coordination between the utility and process sectors. In this study, we will consider especially the vapor recovery of the wastewater from the industrial activity in south Tunisia. By using the heat pump for high capacity, the problem for vapor from wastewater may be resolved. The coupling for the cooling tower and the heat pump system is investigated by TRNSYS software. The system of cooling tower is also associated with a single zone which is related to heat exchangers. An optimization model for the operation of a cooling water system was developed that accounts for a cooling tower, and a network of pipelines and heat exchangers for heating a single house. This work is based on numerical studies; the cooling tower performance, the single house, the heat pump and the heat exchanger that are simulated using TRNSYS model. The circulation of cooling water system is assured by a counter flow. The evaluations of the cooling tower geometry and performances are based on an adaptive version of Merkel�s method witch integrated in TRNSYS. The results of optimization using TRNSYS are validated by several theoretical and experimental studies
Fire behaviour of cooling tower packing; Brandverhalten von Kuehlturmeinbauten
Energy Technology Data Exchange (ETDEWEB)
Mattausch, Tim [DMT GmbH und Co. KG, Dortmund (Germany). Fachstelle fuer Brandschutz
The rapid burning down of the cooling tower of the shutdown power plant in Schwandorf revealed the potential of a total loss of a cooling tower in case of fire. VGB ordered a research project in order to obtain more knowledge about the fire risk of cooling tower packing currently applied. Depending on kind and age of the plastics used, the results of these tests manifest a big variation of the fire behaviour. For the applications of plastics, it is essential to determine and to adhere to organisational fire protection measures. (orig.)
The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers
International Nuclear Information System (INIS)
Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understanding the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative 'dry' cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influencedal in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered
Dynamic behavior and identification of failure modes of cooling towers
International Nuclear Information System (INIS)
The major thrust of this paper is to provide an engineering assessment of two hyperboloidal 540-foot high reinforced concrete cooling towers at a nuclear power plant relative to the proposed construction of a new safety-related facility in the shadow of these cooling towers. A three-dimensional full 360-degree finite-element model that is capable of realistically representing the response of the two cooling towers subjected to the plant design-basis safe shutdown earthquake, 90 mph wind, and 300 mph tornado is used to create a data pool which supports the proposed construction of the new facility. Dynamic time history analyses are performed to represent the complex interplay of the dynamic characteristics of the cooling towers and the input wind-pressure excitation in terms of gust factors. This study resulted in the confirmation and enhancement of many of the important aspects in the design/analysis methodologies for cooling towers reported in literature. In summary, this study provides a high confidence that no significant damage will be caused to the two cooling towers when subjected to the plant design-basis safe shutdown earthquake and the 90 mph basic wind velocity. However, the two cooling towers are expected to collapse if subjected in a direct hit to a 300 mph tornado. The nonlinear finite element analyses including base uplift performed for this study and the literature research on past failures of cooling towers due to severe wind storms confirm that the mo to severe wind storms confirm that the mode of failure will not be the overturning cantilever tree-type and the towers will collapse inwardly with the exception of few isolated debris
Lower parts of Temelin nuclear power plant cooling towers
International Nuclear Information System (INIS)
The progress of work is described in detail on the foundations and lower parts of the cooling towers of the Temelin nuclear power plant. The cooling tower is placed on a reinforced concrete footing of a circular layout. Support pillars are erected on the reinforced concrete continuous footing. They consists of oblique shell stanchions. Inside, the footing joins up to monolithic wall and slab structures of the cooling tower tub. The tub bottom forms a foundation plate supporting prefab structures of the cooling tower inner structural systems. The framed support of the chimney shell consists of 56 pairs of prefabricated oblique stanchions. Following their erection into the final position and anchoring in the continuous footing, the concreting of the casing can start of the reinforced conrete chimney. (Z.M.). 3 figs
Natural-draught cooling towers made of reinforced concrete
International Nuclear Information System (INIS)
Large power plant units and dry cooling tower technology require larger dimensions for natural-draught cooling towers. The main curvation radii in latitudinal and meridian direction are thus increased, which results in a lower three-dimensional support strength. This development is an incentive for constant re-consideration of calculation methods, safety philosophy, and dimensioning criteria. In this context, wind effects have been re-formulated and given a scientific foundation. Constructional measures to improve the static and dynamic behaviour of the structure have been presented and critically assessed. A cost analysis, finally, gave the most rational applications of the new shell construction with reinforcing elements. A cooling tower now under construction gave a realistic example. Fundamental aspects concerning the foundations of cooling tower shells and two special types of foundation are further points to clarify the subject. (orig./HP)
Simultaneous detection of Legionella species and Legionella pneumophila by duplex PCR (dPCR assay in cooling tower water samples from Jakarta, Indonesia
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Andi Yasmon
Full Text Available Aim: Since culture method is time-consuming and has low� sensitivity, we developed a duplex PCR (dPCR assay for the detection of Legionella sp. and L. pneumophila in cooling tower samples. We used culture method as a gold standard.Methods: Optimization of dPCR method was performed to obtain an assay with high sensitivity and specifi city. The optimized method was used to detect Legionella sp. dan L. pneumophila in 9 samples obtained from 9 buildings in Jakarta. For culture method, the bacteria were grown or isolated on selective growth factor supplemented-buffered charcoal yeast extract (BCYE media.Results: Of 9 samples tested by dPCR assay, 6 were positive for Legionella species,1 was positive for L. pneumophila, and 2 showed negative results. For the same samples, no Legionella sp. was detected by the culture method.Conclusion: dPCR assay was much more sensitive than the culture method and was potentially used as a rapid, specifi c and sensitive test for routine detection of Legionella sp. dan for L. pneumophila in water samples. (Med J Indones 2010; 19:223-7Keywords: BCYE media, mip gene, 16S-rRNA gene
Stimulatory effect of cooling tower biocides on amoebae.
S Srikanth; Berk, S. G.
Two species of amoebae were isolated from the cooling tower of an air-conditioning system and examined for effects of exposure to four cooling tower biocides, a thiocarbamate compound, tributyltin neodecanoate mixed with quaternary ammonium compounds, another quaternary ammonium compound alone, and an isothiazolin derivative. The amoebae isolated were Acanthamoeba hatchetti and a Cochliopodium species. Two other amoeba cultures, an A. hatchetti culture and Cochliopodium bilimbosum, were obtai...
Performance evaluations of steam power plants with dry cooling towers
International Nuclear Information System (INIS)
A theoretical model is presented to design dry cooling tower systems and to evaluate their off-design performances. The influence of the more important design parameters on the tower dimensions is shown. A preliminary ''optimum'' size is predicted by means of a computer code using a simplified cost model. Moreover the influence of the designed cooling system on the performance of thermoelectric and/or nuclear power plants is analysed
Experimental study and predictions of an induced draft ceramic tile packing cooling tower
International Nuclear Information System (INIS)
Deterioration of the filling material in traditional cooling towers is of serious concern. In this study, long life burned clay is used as the filling material. It guards against common cooling tower problems resulting from chemical water treatment and deterioration. The size of the ceramic packing material and outlet conditions predictions by theoretical modeling require heat and mass transfer correlations. An experimental study to evaluate the heat and mass transfer coefficients is conducted. The previous correlations found in the literature could not predict the mass transfer coefficient for the tested tower. A mass transfer coefficient correlation is developed, and new variables are defined. This correlation can predict the mass transfer coefficient within an error of �10%. The developed correlation is used along with theoretical modeling to predict the cooling tower outlet conditions within an error of �5%
Evaluation of the RSG-GAS cooling tower performance
International Nuclear Information System (INIS)
Utilization of RSG-GAS reactor should be operated as efficiently as possible, so that reactor operation planning using one line primary coolant can be anticipated. To analyze the performance of the RSG-GAS cooling tower with one line primary coolant doing by using same data from 10 MW thermal reactor operation. The result were then compare to those achieved using CATHENA code. The results indicated that, for design condition the ratio of water flowrate to air is (L/G) 1.52 and number transfer unit (NTU) is 0.348. For operation condition, the average of L/G and NTU are respectively 1.37 and 0,348. Moreover the results achieved by the code showed that L/G and NTU are respectively 1.35 and 0,302. The performance of cooling tower achieved operation condition and the code results are respectively 91% and 72%. This means that the calculated results are lower than measurement results
Hudson River cooling tower proceeding: Interface between science and law
International Nuclear Information System (INIS)
As the Hudson River power plant case proceeded, the regulatory ground shifted under the utility companies. At first, the US Environmental Protection Agency (EPA) contended that the utilities should build expensive closed-cycle cooling towers at three plants to minimize the plants' discharge of heated effluents to the river. When the formal hearing began, however, EPA claimed that cooling towers were needed to minimize the number of organisms impinged at and entrained through the plants. The Hudson River proceeding became a policy dispute over what the appropriate standard of environmental conduct should be, instead of a determination of whether a standard had been met or not. Such policy issues, which arise when legal precedent has yet to be developed for new laws like the Clean Water Act, are better addressed by a rule-making proceeding than by the adjudicatory hearing format used in the Hudson case. A rule-making proceeding would have markedly shortened the Hudson deliberations, probably without substantive change in the final settlement, and is recommended for future cases in which ambiguity in legislation or the lack of precedent has left policy matters unresolved. 2 refs
An exergy analysis on the performance of a counterflow wet cooling tower
International Nuclear Information System (INIS)
Cooling towers are used to extract waste heat from water to atmospheric air. An energy analysis is usually used to investigate the performance characteristics of cooling tower. However, the energy concept alone is insufficient to describe some important viewpoints on energy utilization. In this study, an exergy analysis is used to indicate exergy and exergy destruction of water and air flowing through the cooling tower. Mathematical model based on heat and mass transfer principle is developed to find the properties of water and air, which will be further used in exergy analysis. The model is validated against experimental data. It is noted from the results that the amount of exergy supplied by water is larger than that absorbed by air, because the system produces entropy. To depict the utilizable exergy between water and air, exergy of each working fluid along the tower are presented. The results show that water exergy decreases continuously from top to bottom. On the other hand, air exergy is expressed in terms of convective and evaporative heat transfer. Exergy of air via convective heat transfer initially loses at inlet and slightly recovers along the flow before leaving the tower. However, exergy of air via evaporative heat transfer is generally high and able to consume exergy supplied by water. Exergy destruction is defined as the difference between water exergy change and air exergy change. It reveals that the cooling processes due to thermodynamics irreversibilocesses due to thermodynamics irreversibility perform poorly at bottom and gradually improve along the height of the tower. The results show that the lowest exergy destruction is located at the top of the tower
Flue gas injection control of silica in cooling towers.
Energy Technology Data Exchange (ETDEWEB)
Brady, Patrick Vane; Anderson, Howard L., Jr.; Altman, Susan Jeanne
Injection of CO{sub 2}-laden flue gas can decrease the potential for silica and calcite scale formation in cooling tower blowdown by lowering solution pH to decrease equilibrium calcite solubility and kinetic rates of silica polymerization. Flue gas injection might best inhibit scale formation in power plant cooling towers that use impaired makeup waters - for example, groundwaters that contain relatively high levels of calcium, alkalinity, and silica. Groundwaters brought to the surface for cooling will degas CO{sub 2} and increase their pH by 1-2 units, possibly precipitating calcite in the process. Recarbonation with flue gas can lower the pHs of these fluids back to roughly their initial pH. Flue gas carbonation probably cannot lower pHs to much below pH 6 because the pHs of impaired waters, once outgassed at the surface, are likely to be relatively alkaline. Silica polymerization to form scale occurs most rapidly at pH {approx} 8.3 at 25 C; polymerization is slower at higher and lower pH. pH 7 fluids containing {approx}220 ppm SiO{sub 2} require > 180 hours equilibration to begin forming scale whereas at pH 8.3 scale formation is complete within 36 hours. Flue gas injection that lowers pHs to {approx} 7 should allow substantially higher concentration factors. Periodic cycling to lower recoveries - hence lower silica concentrations - might be required though. Higher concentration factors enabled by flue gas injection should decrease concentrate volumes and disposal costs by roughly half.
Alternative geometry for cylindrical natural draft cooling tower with higher cooling efficiency under crosswind condition
International Nuclear Information System (INIS)
Highlights: � Alternative cross sections for natural draft cooling tower were proposed. � Numerical solution was applied to study thermal and hydraulic performances. � Thermal and hydraulic performances were assessed by comparative parameters. � Cooling tower with elliptical cross section had better thermal performance under crosswind. � It could successfully used at the regions with invariant wind direction. - Abstract: Cooling efficiency of a natural draft dry cooling tower may significantly decrease under crosswind condition. Therefore, many researchers attempted to improve the cooling efficiency under this condition by using structural or mechanical facilities. In this article, alternative shell geometry with elliptical cross section is proposed for this type of cooling tower instead of usual shell geometry with circular cross section. Thermal performance and cooling efficiency of the two types of cooling towers are numerically investigated. Numerical simulations show that cooling tower with elliptical cross section improves the cooling efficiency compared to the usual type with circular cross section under high-speed wind moving normal to the longitudinal diameter of the elliptical cooling tower
Statistical multi-model approach for performance assessment of cooling tower
International Nuclear Information System (INIS)
This paper presents a data-driven model-based assessment strategy to investigate the performance of a cooling tower. In order to achieve this objective, the operations of a cooling tower are first characterized using a data-driven method, multiple models, which presents a set of local models in the format of linear equations. Satisfactory fuzzy c-mean clustering algorithm is used to classify operating data into several groups to build local models. The developed models are then applied to predict the performance of the system based on design input parameters provided by the manufacturer. The tower characteristics are also investigated using the proposed models via the effects of the water/air flow ratio. The predicted results tend to agree well with the calculated tower characteristics using actual measured operating data from an industrial plant. By comparison with the design characteristic curve provided by the manufacturer, the effectiveness of cooling tower can be obtained in the end. A case study conducted in a commercial plant demonstrates the validity of proposed approach. It should be noted that this is the first attempt to assess the cooling efficiency which is deviated from the original design value using operating data for an industrial scale process. Moreover, the evaluated process need not interrupt the normal operation of the cooling tower. This should be of particular interest in industrial applications.
Computer optimization of dry and wet/dry cooling tower systems for large fossil and nuclear power plants
International Nuclear Information System (INIS)
This study determined the cost of dry cooling compared to the conventional cooling methods. Also, the savings by using wet/dry instead of all-dry cooling were determined. A total optimization was performed for power plants with dry cooling tower systems using metal-finned-tube heat exchangers and surface condensers. The optimization minimizes the power production cost. The program optimizes the design of the heat exchanger and its air and water flow rates. In the base case study, the method of replacing lost capacity assumes the use of gas turbines. As a result of using dry cooling towers in an 800 MWe fossil plant, the incremental costs with the use of high back pressure turbine and conventional turbine over all-wet cooling are 11 and 15%, respectively. For a 1200 MWe nuclear plant, these are 22 and 25%, respectively. Since the method of making up lost capacity depends on the situation of a utility, considerable effort has been placed on testing the effects of using different methods of replacing lost capacity at high ambient temperatures by purchased energy. The results indicate that the optimization is very sensitive to the method of making up lost capacity. It is, therefore, important to do an accurate representation of all possible methods of making up capacity loss when optimizating power plants with dry cooling towers. A solution for the problem of losing generation capability by a power plant due to the use of a dry cooling tower is to supplement the dry toweroling tower is to supplement the dry tower during the hours of peak ambient temperatures by a wet tower. A separate wet/dry cooling tower system with series tower arrangement was considered in this study, and proved to be an economic choice over all-dry cooling where some water is available but supplies are insufficient for a totally evaporative cooling tower
Atmospheric wet-type cooling tower with antifreeze system
International Nuclear Information System (INIS)
The cooling tower has air inlets at its base, a network of pipes which distributes the air to be cooled above the packing, and valves to isolate a part of the network. It includes also a bypass circuit, provided with means to control the flow rate fraction which is by-passed
Short-term pilot cooling tower tests
Energy Technology Data Exchange (ETDEWEB)
Suciu, D.F.; Miller, R.L.
Two major problems are associated with the use of cooled geothermal water as coolant for the 5 MW(e) pilot plant at Raft River. They are: (1) a scaling potential owing to the chemical species present in solution, and (2) the corrosive nature of the geothermal water. Tests were conducted to obtain data so that methods can be devised to either reduce or eliminate effects from these problems. Data show that scaling can be prevented, but only by using a high concentration of dispersant. Pitting data, however, are not as conclusive and seem to indicate that pitting control cannot be realized, but this result cannot be substantiated without additional experimentation. Results also demonstrate that chromate can be removed by using either chemical destruction or ion exchange. Whichever method is used, EPA discharge limits for both chromate and zinc can be achieved. A preliminary economic analysis is presented.
Energy Technology Data Exchange (ETDEWEB)
Lee, S.; Garrett, A.; Bollinger, J.
Mechanical draft cooling towers are designed to cool process water via sensible and latent heat transfer to air. Heat and mass transfer take place simultaneously. Heat is transferred as sensible heat due to the temperature difference between liquid and gas phases, and as the latent heat of the water as it evaporates. Mass of water vapor is transferred due to the difference between the vapor pressure at the air-liquid interface and the partial pressure of water vapor in the bulk of the air. Equations to govern these phenomena are discussed here. The governing equations are solved by taking a computational fluid dynamics (CFD) approach. The purpose of the work is to develop a three-dimensional CFD model to evaluate the flow patterns inside the cooling tower cell driven by cooling fan and wind, considering the cooling fans to be on or off. Two types of the cooling towers are considered here. One is cross-flow type cooling tower located in A-Area, and the other is counterflow type cooling tower located in H-Area. The cooling tower located in A-Area is mechanical draft cooling tower (MDCT) consisting of four compartment cells as shown in Fig. 1. It is 13.7m wide, 36.8m long, and 9.4m high. Each cell has its own cooling fan and shroud without any flow communications between two adjacent cells. There are water distribution decks on both sides of the fan shroud. The deck floor has an array of about 25mm size holes through which water droplet falls into the cell region cooled by the ambient air driven by fan and wind, and it is eventually collected in basin area. As shown in Fig. 1, about 0.15-m thick drift eliminator allows ambient air to be humidified through the evaporative cooling process without entrainment of water droplets into the shroud exit. The H-Area cooling tower is about 7.3 m wide, 29.3 m long, and 9.0 m high. Each cell has its own cooling fan and shroud, but each of two corner cells has two panels to shield wind at the bottom of the cells. There is some degree of flow communications between adjacent cells through the 9-in gap at the bottom of the tower cells as shown in Fig. 2. Detailed geometrical dimensions for the H-Area tower configurations are presented in the figure. The model was benchmarked and verified against off-site and on-site test results. The verified model was applied to the investigation of cooling fan and wind effects on water cooling in cells when fans are off and on. This report will discuss the modeling and test results.
Predicted climatology of cooling tower plumes from energy centers
International Nuclear Information System (INIS)
A one-dimensional plume and cloud growth model is applied to four months of radiosonde observations from Nashville, using as initial conditions the plume from single large cooling towers with waste heat outputs of 103, 104 and 105 MW, and a complex of cooling towers with a total waste heat output of 105 MW. Estimates of average annual plume rise from the four energy sources are 580, 1180, 2460 and 780 m, respectively.The predicted plume rise, visible plume length and cloud formation are given as functions of time of day, year and weather type. For example, a cloud forms at the top of the plume from the 103 MW tower in 65% of the morning soundings during which ground level fog was observed. A cloud is predicted to occur 95% of the time at the top of the plume from the single 105 MW tower. It is found that if the towers in an energy center are separated by a distance greater than the average plume rise from one tower, then plume merging is minimized. Observations from TVA's Paradise steam plant are used to test the predictions of visible plume length from a single 103 MW tower
Cooling towers for 1000 MW nuclear power unit
International Nuclear Information System (INIS)
The project is discussed of one single cooling tower with natural draft for one nuclear power plant unit. Two towers are designed for one unit of the Temelin power plant and the construction of one single tower for one unit is being considered. A brief economic analysis is made on the basis of experience and foreign data, and a comparison made with Czechoslovak projects. The use of a single tower will save 20% of capital costs and further savings will be achieved in the pipelines and built-up area. The relative cost of the tower depends on the temperature of ambient air, the dimensions of the tower, on shower intensity. There are also considerable differences in power generation with constant heat consumption. Briefly presented is the procedure of the calculation of deviations in power generation from rated states, which are the basis for economic evaluation and the choice of the optimal variant of cooling towers. (M.D.). 8 figs., 2 tabs., 6 refs
Mistral: New test bench for cooling tower components
International Nuclear Information System (INIS)
The use of the test bench for cooling tower components of Nantes-Chevire, useful counterflow cross-section: 7m x 7m, has shown the adequacy of this large tool for the study of large equipment and the elimination of the boundary effect (boundary effect coefficient between 1.2 and 1.5). After having decommissioned this bench, Electricite de France built the Mistral bench at the Nuclear Generation Centre of Bugey. It is equipped with two test systems. The cross-section of the counterflow system is 7m x 7m and its useful height, 3.5m. The cross-section of the cross-flow system is 5 x 10m and its depth 10m. Water and air flows can reach respectively 600 1 per sec. and 225m3 per sec. for a maximum thermal capacity of 25 MW
Simultaneous detection of Legionella species and Legionella pneumophila by duplex PCR (dPCR) assay in cooling tower water samples from Jakarta, Indonesia
Andi Yasmon; Yusmaniar Yusmaniar; Anis Anis; Budiman Bela
Aim: Since culture method is time-consuming and has low� sensitivity, we developed a duplex PCR (dPCR) assay for the detection of Legionella sp. and L. pneumophila in cooling tower samples. We used culture method as a gold standard.Methods: Optimization of dPCR method was performed to obtain an assay with high sensitivity and specifi city. The optimized method was used to detect Legionella sp. dan L. pneumophila in 9 samples obtained from 9 buildings in Jakarta. For culture method, the bacte...
Modeling of hydronic radiant cooling of a thermally homeostatic building using a parametric cooling tower
International Nuclear Information System (INIS)
Highlights: � Investigated cooling of thermally homeostatic buildings in 7 U.S. cities by modeling. � Natural energy is harnessed by cooling tower to extract heat for building cooling. � Systematically studied possibility and conditions of using cooling tower in buildings. � Diurnal ambient temperature amplitude is taken into account in cooling tower cooling. � Homeostatic building cooling is possible in locations with large ambient T amplitude. - Abstract: A case is made that while it is important to mitigate dissipative losses associated with heat dissipation and mechanical/electrical resistance for engineering efficiency gain, the �architect� of energy efficiency is the conception of best heat extraction frameworks�which determine the realm of possible efficiency. This precept is applied to building energy efficiency here. Following a proposed process assumption-based design method, which was used for determining the required thermal qualities of building thermal autonomy, this paper continues this line of investigation and applies heat extraction approach investigating the extent of building partial homeostasis and the possibility of full homeostasis by using cooling tower in one summer in seven selected U.S. cities. Cooling tower heat extraction is applied parametrically to hydronically activated radiant-surfaces model-buildings. Instead of sizing equipment as a function of design peak hourly temperature as it is done in heat balance design-approach of selecting HVAC equipment, it is shown that the conditions of using cooling tower depend on both �design-peak� daily-mean temperature and the distribution of diurnal range in hourly temperature (i.e., diurnal temperature amplitude). Our study indicates that homeostatic building with natural cooling (by cooling tower alone) is possible only in locations of special meso-scale climatic condition such as Sacramento, CA. In other locations the use of cooling tower alone can only achieve homeostasis partially
Calculation of cooling tower plumes for high pressure wintry situations
International Nuclear Information System (INIS)
The diffusion of the plumes of the projected nuclear power plants at Kaiseraugst and Schwoerstadt, during high pressure wintry conditions, has been examined using a mathematical model to simulate the plumes. For these calculations, microaerological measurements were made in the proximity of Kaiseraugst and Schwoerstadt. These give a typical image of the weather during high pressure wintry conditions, which is normally associated with an inversion, sometimes strong, at a low height. Dry cooling towers with natural draught, which offer an alternative solution to the wet cooling towers proposed for Kasieraugst, are examined equally. (Auth./G.T.H.)
Numerical analysis of crosswind effect on wet cooling tower aerodynamic field
International Nuclear Information System (INIS)
Based on CFD code FLUENT, three-dimensional numerical analyses were carried out for natural draft wet cooling tower under crosswind conditions.Sensitivity analyses to parameters such as ambient crosswind velocity profile and water droplet equivalent diameter validated the adopted numerical model. The effect of crosswind on wet cooling tower inner and outer aerodynamic field and tower internal heat and mass transfer performance were investigated numerically. The results show that crosswind causes the increase of air inflow relative departure degree and induces horizontal air mass flow rate which improves rain zone heat and mass transfer but reduces tower vertical air mass flow rate, and then produces an unfavorable effect on fill zone and increases outflow water temperature. The analyses about air inflow relative departure degree show that improving the air inflow aerodynamic field can reduce the unfavorable effect of crosswind on the circumference distribution of air inlet air radial velocity and then improve the total cooling performance of wet cooling tower under crosswind conditions. (authors)
Maintenance of the auxiliary component cooling water system and the general cooling water system in HTTR
International Nuclear Information System (INIS)
The High Temperature Engineering Test Reactor (HTTR) has the Auxiliary Component Cooling Water System (ACCWS) and the General Cooling Water System (GCWS). ACCWS supplies the cooling water to the many facilities those are necessary to operate and cool the reactor. GCWS supplies the cooling water to the many facilities those are necessary to operate and cool the reactor in normal circumstances. Two kinds of the cooling water are cooled with the Cooling Tower. Each facility has the circulation pump, the cooling tower, the piping, the valve, the strainer and the injection system of the chemical solution. And these two facilities are operating all the year. This report describes maintenance items, improvements and management of the ACCWS and the GCWS. (author)
A construction method of reinforced-concrete very high stacks and natural draft cooling towers
International Nuclear Information System (INIS)
The new Shimizu flex-lip system was developed by the Shimizu Construction Co., Ltd. for constructing very high (about 200 m) towers made of reinforced concrete. Utilizing this system, towers of any shape, circular, triangular, square and polygonal, can be constructed. The wall thickness can be varied from 200 mm to 1 m. The diameter of towers can be enlarged from 3 m to any valve and the inclination of tower walls can be designed in any way between +1/5 and -1/5. The advantage of this system is to use the jack down mechanism, to test concrete strength without sampling, to reduce the connections of reinforcing steel bars and to adopt the continuous, and to use automatic measuring system using laser for checking up positional error. The design and analysis of high tower structures were systemized and automated with the development of the flex-lip construction method. The several past records of having applied this method to industrial areas are shown. As for natural draft cooling towers, the Shimizu jump-up system has been studied for the cooling water capacity of 60,000 m3/h. The towers are 120 m high, 110 m in diameter at the bottom and 65 m in diameter at the top. The advantage of this construction method, the plan of concrete jump-up and the construction test are explained. (Nakai, Y.)
Effects of wet cooling towers on weather and climatic conditions
International Nuclear Information System (INIS)
Type and efficiency of the occuring process are treated in connection with the important external conditions. The description of the direct effects and the indirect as well leads to the conclusion that thorough investigations of environmental influences by wet cooling towers have to be carried out in a few particular cases only. (orig.)
Discussion on NPP cooling tower's load value according to British BS, German BTR and Chinese codes
International Nuclear Information System (INIS)
Design of nuclear power plant cooling tower is a new task for NPP CI design. Requirements on NPP safety and utilization are different from those on common fossil-fired power plants and the design of cooling tower is an important aspect. Specifications on values of cooling tower design load in British BS, German BTR and Chinese codes (on hydraulic structures) are analyzed and compared. A few significant conclusions reached are helpful reference for NPP cooling tower design. (authors)
Optimization design of solar enhanced natural draft dry cooling tower
International Nuclear Information System (INIS)
Highlights: � We proposed a cost model for solar enhanced natural draft dry cooling tower. � We proposed an optimization scheme for this new cooling system. � We optimally designed one for a 50 MW EGS geothermal plant as a demonstration. � Results proved its economic advantages for EGS geothermal application. - Abstract: This paper proposed an optimization scheme for solar enhanced natural draft dry cooling tower design, in which a detailed cost model was proposed including capital, labour, maintenance and operation costs of each component. Based on the developed cost model, the optimal design option can be identified in terms of the relatively lower annual cost and the relatively higher total extra income over the Solar Enhanced Natural Draft Dry Cooling Tower (SENDDCT) lifetime. As a case study, a SENDDCT was optimally designed to meet the cooling demand for a 50 MW geothermal power plant with Engineered Geothermal System (EGS) technology. The results showed that the optimized SENDDCT not only has better cooling performance during the daytime but also is a cost effective option for EGS geothermal power plants
Study the factors on which efficiency of cooling tower can be critically acclaimed (A case Study
Directory of Open Access Journals (Sweden)
Krishna S. Vishwakarma
Full Text Available Water cooling is widely used in many industrial processes to control heat removal from a hot material surface. In order to control the temperature distributions, a deeper understanding more accurate estimation of spray heat transfer rates is needed. In a new technique combining experiment and computational modeling developed for water cooling. It is better to understand the heat transfer mechanisms from the combustion gases to the cooling water and then from the cooling water to the environment. To meet this need a logic tree is developed to provide guidance on how to balance and identify problems within cooling system and schedule appropriate maintenance. Fluid dynamics, Thermodynamics and Heat transfer are involved in developing a cooling system model and the operation is familiar to the general operating companies. There will be the comparison and parametric investigation of the cooling system model in the logic tree and the results are summarized as tables and charts. The objective is to identify the several ways of improving efficiency of cooling tower. In this study we are doing the comparison ofsome calculations regarding the cooling tower.
Magnetic fluid conditioning system allows 3000 ppm hardness without cooling tower scale buildup
International Nuclear Information System (INIS)
Big Three Industries, a manufacturer of compressed and liquefied atmospheric gases, operates a large production complex in Bayport, TX which recirculates 100,000 gpm cooling water. Due to regulatory agency guidelines, high costs, and limited effectiveness of conventional chemical treatment methods, Big Three was in need of a treatment method to prevent corrosion and scaling in recirculating water cooling systems. In December 1983 a magnetic fluid conditioner (MFC) was installed in the pump discharge piping of one cooling tower at Bayport. The patented MFC is an 18'' long spool pipe fitted with uranium-based alloy magnets. The MFC has no moving parts and requires no chemicals, external power source, or maintenance. The MFC is designed so that the fluid is accelerated through a magnetic field. The high velocity of the fluid causes nucleation of the salts in the fluid. The salts are separated from the water by precipitation. During eighteen months of using the MFC, the cooling tower has concentrated in excess of 50 cycles. Conductivity is in excess of 10,000 micromhos, and total hardness (CaCO3) is above 4000 ppm with pH stabilized between 8 and 9. However, inspections have revealed clean surfaces. The cleaner metal surfaces within the cooling water system provide better heat transfer which has resulted in reduction of tower blowdown, makeup water requirements, and pumping costs. Associated savings will enable the MFC to achieve payback in two and a half years
Recent developments in the design of large cooling towers
International Nuclear Information System (INIS)
The growth of power plant units has initiated the development of very large cooling towers. The shell curvature of such towers is comparably small producing an increase of bending effects due to loads with a non-uniform distribution, such as turbulent wind pressures. The validity of the current concept of equivalent static wind loads is inspected. Some deficiencies may occur underrating the actual stresses. A simplified, quasi-static method of calculation is described including dynamic loading data obtained from wind-tunnel tests. (Author)
Biocide usage in cooling towers in the electric power and petroleum refining industries
Energy Technology Data Exchange (ETDEWEB)
Veil, J.; Rice, J.K.; Raivel, M.E.S.
Cooling towers users frequently apply biocides to the circulating cooling water to control growth of microorganisms, algae, and macroorganisms. Because of the toxic properties of biocides, there is a potential for the regulatory controls on their use and discharge to become increasingly more stringent. This report examines the types of biocides used in cooling towers by companies in the electric power and petroleum refining industries, and the experiences those companies have had in dealing with agencies that regulate cooling tower blowdown discharges. Results from a sample of 67 electric power plants indicate that the use of oxidizing biocides (particularly chlorine) is favored. Quaternary ammonia salts (quats), a type of nonoxidizing biocide, are also used in many power plant cooling towers. The experience of dealing with regulators to obtain approval to discharge biocides differs significantly between the two industries. In the electric power industry, discharges of any new biocide typically must be approved in writing by the regulatory agency. The approval process for refineries is less formal. In most cases, the refinery must notify the regulatory agency that it is planning to use a new biocide, but the refinery does not need to get written approval before using it. The conclusion of the report is that few of the surveyed facilities are having any difficulty in using and discharging the biocides they want to use.
Evaluation of plume potential and plume abatement of evaporative cooling towers in a subtropical region
International Nuclear Information System (INIS)
Hong Kong is a typical subtropical region with frequently high humidity in late spring and summer seasons. Plume from evaporative cooling towers, which service air-conditioning systems of civil buildings, has aroused public concerns since 2000 when the fresh water evaporative cooling towers were allowed to be used for high energy efficiency and environmental issues. This paper presents the evaluation of the plume potential and its effect on the sizing of the plume abatement system in a large commercial office building in Hong Kong for practical application. This evaluation was conducted based on a dynamic simulation platform using the typical meteorological year of Hong Kong since the occurrence of the plume heavily depends on the state conditions of the exhaust air from cooling towers and the ambient air, while the state condition of the exhaust air is determined by the total building cooling load and the control strategies of cooling towers employed mainly for improving energy efficiency. The results show that the control strategies have a significant effect on the plume potential and further affect the system design and sizing of the plume abatement system
The results of the measurements of mass- and heat-transfer in the wet cooling tower
International Nuclear Information System (INIS)
These are the results of our investigations carried out on a packing inside a wet cooling tower for the purpose of studying the mass and heat transfer at the counterflow of water and humid air. The measurements on the experimental tower of the corresponding mathematical model reflect the average coefficient of mass and heat transfer for the unity of the active volume. Further the measurements of pressure drop at the air flow were carried out and thus the coefficient of aerodynamic losses were obtained. The results of measurements are given in the corresponding equations with the dimensionless numbers and diagrams. They will be of great use for the planning of new cooling towers. (author)
Numerical modeling of cooling tower plumes: comparison with experiments
International Nuclear Information System (INIS)
This chapter compares mathematical models designed to study the impact of cooling tower plumes from a nuclear power plant in France. The 3 models are an integral model for a statistical evaluation of plume characteristics and their cumulative effect (reduction of insolation); a spectral microphysical model, to study the interaction processes between a natural cloud and the plume; and a 3D plume model, involving both dynamics, microphysics and their coupling, to investigate the problems of plumes development, especially in convective situations (cumuli formation). Experimental data were obtained near the BUGEY nuclear power plant (two units of 900 MWe, two natural draft cooling towers per unit). The three models currently used are compared to the experimental data. Includes 3 tables and 3 drawings
Thickness cracks in R.C. hyperbolic cooling towers
International Nuclear Information System (INIS)
Imprecise construction work might cause imperfection in the shell of R.C. hyperbolic cooling towers. By considering the three directions concrete fracture model and by using elements in finite element analysis which could crack in three directions, it could be shown that in imperfect shell, the thickness cracks occur at the end of the weight and thermal loads. In the other words, the inside and outside of the concrete shell separate. The number of such cracks rises up by increasing the imperfection in the cooling tower shell. This increase in the number of cracks could multiple when two concavity and convexity imperfections happen consecutively. Since there is not any reinforce bar for preventing of such cracks, so it must be avoided by precise construction work and by modifying the participating thermal load factor in combining loads
Numerical research of a super-large cooling tower subjected to accidental loads
Energy Technology Data Exchange (ETDEWEB)
Li, Yi; Lin, Feng [Department of Building Engineering, Tongji University, Shanghai 200092 (China); Gu, Xianglin, E-mail: firstname.lastname@example.com [Department of Building Engineering, Tongji University, Shanghai 200092 (China); Lu, Xiaoqin [Guangdong Electric Power Design Institute, Guangzhou 510660 (China)
With the continued development of nuclear power plants, more and more super-large cooling towers are to be built in China and around the world. For the safe operation of nuclear power plants, research work has been done on the causes of collapse of cooling towers, collapse modes and the secondary disasters caused by the collapse of cooling towers. However, the collapse modes and the ground vibration induced by the collapse of cooling towers subjected to the accidental loads have not been fully understood. This paper has been focused on the modes and mechanisms behavior of the collapse of cooling towers subjected to accidental loads. Meanwhile, prediction of the ground vibration due to the collapse of the cooling towers has also been completed in a parallel project. Using dynamic finite element program LS-DYNA, a 3D finite element model for a super-large cooling tower was developed and the nonlinear material models were incorporated. In this paper, four types of accidental loads were considered to trigger the collapse or local failure of the tower, including vehicle collision, airplane impact, local explosion and missile attack. It was found that vehicle collision, missile attack and small TNT equivalent explosives (2 kg, 20 kg, 200 kg) might result in local failure of the cooling tower, however, the tower can still keep stable. On the other hand, large TNT equivalent explosives (2000 kg, 4500 kg) could cause severe damages in the inclined columns of the cooling tower, and lead to progressive collapse of the entire cooling tower. The two kinds of TNT equivalent explosives caused the same collapse mode while the collapsing duration was different. The airplane impacted at the throat of the cooling tower caused the local failure of shell structure of the tower, and then the progressive collapse of the cooling tower happened due to the gravitational action. The resulting collapse mode was different from that triggered by the local explosion.
Numerical research of a super-large cooling tower subjected to accidental loads
International Nuclear Information System (INIS)
With the continued development of nuclear power plants, more and more super-large cooling towers are to be built in China and around the world. For the safe operation of nuclear power plants, research work has been done on the causes of collapse of cooling towers, collapse modes and the secondary disasters caused by the collapse of cooling towers. However, the collapse modes and the ground vibration induced by the collapse of cooling towers subjected to the accidental loads have not been fully understood. This paper has been focused on the modes and mechanisms behavior of the collapse of cooling towers subjected to accidental loads. Meanwhile, prediction of the ground vibration due to the collapse of the cooling towers has also been completed in a parallel project. Using dynamic finite element program LS-DYNA, a 3D finite element model for a super-large cooling tower was developed and the nonlinear material models were incorporated. In this paper, four types of accidental loads were considered to trigger the collapse or local failure of the tower, including vehicle collision, airplane impact, local explosion and missile attack. It was found that vehicle collision, missile attack and small TNT equivalent explosives (2 kg, 20 kg, 200 kg) might result in local failure of the cooling tower, however, the tower can still keep stable. On the other hand, large TNT equivalent explosives (2000 kg, 4500 kg) could cause severe damages in the inclined columns of the cooling tower, and lead to progressive collapse of the entire cooling tower. The two kinds of TNT equivalent explosives caused the same collapse mode while the collapsing duration was different. The airplane impacted at the throat of the cooling tower caused the local failure of shell structure of the tower, and then the progressive collapse of the cooling tower happened due to the gravitational action. The resulting collapse mode was different from that triggered by the local explosion
Operational cost minimization in cooling water systems
Scientific Electronic Library Online (English)
M.M., Castro; T.W., Song; J.M., Pinto.
Full Text Available In this work, an optimization model that considers thermal and hydraulic interactions is developed for a cooling water system. It is a closed loop consisting of a cooling tower unit, circulation pump, blower and heat exchanger-pipe network. Aside from process disturbances, climatic fluctuations are [...] considered. Model constraints include relations concerning tower performance, air flowrate requirement, make-up flowrate, circulating pump performance, heat load in each cooler, pressure drop constraints and climatic conditions. The objective function is operating cost minimization. Optimization variables are air flowrate, forced water withdrawal upstream the tower, and valve adjustment in each branch. It is found that the most significant operating cost is related to electricity. However, for cooled water temperatures lower than a specific target, there must be a forced withdrawal of circulating water and further makeup to enhance the cooling tower capacity. Additionally, the system is optimized along the months. The results corroborate the fact that the most important variable on cooling tower performance is not the air temperature itself, but its humidity.
Operational cost minimization in cooling water systems
Directory of Open Access Journals (Sweden)
Castro M.M.
Full Text Available In this work, an optimization model that considers thermal and hydraulic interactions is developed for a cooling water system. It is a closed loop consisting of a cooling tower unit, circulation pump, blower and heat exchanger-pipe network. Aside from process disturbances, climatic fluctuations are considered. Model constraints include relations concerning tower performance, air flowrate requirement, make-up flowrate, circulating pump performance, heat load in each cooler, pressure drop constraints and climatic conditions. The objective function is operating cost minimization. Optimization variables are air flowrate, forced water withdrawal upstream the tower, and valve adjustment in each branch. It is found that the most significant operating cost is related to electricity. However, for cooled water temperatures lower than a specific target, there must be a forced withdrawal of circulating water and further makeup to enhance the cooling tower capacity. Additionally, the system is optimized along the months. The results corroborate the fact that the most important variable on cooling tower performance is not the air temperature itself, but its humidity.
Vibration Analysis of a Cooling Fan Gear Reducer of the Secondary Cooling Tower in HANARO
International Nuclear Information System (INIS)
HANARO is an open-tank-in-pool-type Korean research reactor that generates 30MW of thermal power. It differs from power plant reactor in that the heat generated by HANARO is exhausted into the atmosphere through a secondary cooling tower, thus maintaining the core temperature constant. During every monthly inspection of the cooling tower, large vibrations that exceeded the permissible limit were observed at cooling fan gear reducer No. 4 of the cooling tower. The purpose of this study is to identify the origin of the large vibration and to repair it. FFT spectrum analysis is performed to identify the part that caused the large vibration. The results of the frequency analysis showed that the vibration frequency was 354 Hz, which is twice the natural frequency of the pinion gear. A check of the pinion gear revealed that there was a crack on the surface of the pinion gear. After the gear was replaced, the reducer operated normally
Modeling of heat transfer in cooling towers with natural convection.
Czech Academy of Sciences Publication Activity Database
Zuniga-Gonzalez, Israel; Mar��k, Franti�ek
Gdansk : IFFM Publishers, 2005 - (Mikielewicz, J.; Butrymowicz, D.; Trela, M.; Cie?li?ski, J.), s. 585-592 ISBN 83-88237-90-X. [HEAT 2005 : International Conference on Transport Phenomena in Multiphase Systems. Gdansk (PL), 26.06.2005-30.06.2005] R&D Projects: GA ?R GA101/02/0364; GA ?R(CZ) GA101/05/2536 Institutional research plan: CEZ:AV0Z20760514 Keywords : cooling tower * heat transfer * evaporative cooling Subject RIV: BK - Fluid Dynamics
Cementitious stabilization of chromium, arsenic, and selenium in a cooling tower sludge
International Nuclear Information System (INIS)
The Federal Facility Compliance Agreement (FFCA) establishes an aggressive schedule for conducting studies and treatment method development under the treatability exclusion of RCRA for those mixed wastes for which treatment methods and capabilities have yet to be defined. One of these wastes is a radioactive cooling tower sludge. This paper presents some results of a treatability study of the stabilization of this cooling tower sludge in cementitious waste forms. The sample of the cooling tower sludge obtained for this study was found to be not characteristically hazardous in regard to arsenic, barium, chromium, lead, and selenium, despite the waste codes associated with this waste. However, the scope of this study included spiking three RCRA metals to two orders of magnitude above the initial concentration to test the limits of cementitious stabilization. Chromium and arsenic were spiked at concentrations of 200, 2,000, and 20,000 mg/kg, and selenium was spiked at 100, 1,000, and 10,000 mg/kg (concentrations based on the metal in the sludge solids). Portland cement, Class F fly ash, and slag were selected as stabilizing agents in the present study. Perlite, a fine, porous volcanic rock commonly used as a filter aid, was used as a water-sorptive agent in this study in order to control bleed water for high water contents. The highly porous perlite dust absorbs large amounts of water by capillary action and does not present the handling and processing problems exhibited by clays used for bleed water control
The Worlds First Ever Cooling Tower Acceptance Test Using Process Data Reconciliation
International Nuclear Information System (INIS)
The cooling capacity of cooling towers is influenced by multiple constructive and atmospheric parameters in a very complex way. This leads to strong variations of the measured cold-water temperature and causes unacceptable unreliability of conventional acceptance tests, which are based on single point measurements. In order to overcome this lack of accuracy a new approach to acceptance test based on process data reconciliation has been developed by BTB Jansky and applied at a nuclear power plant. This approach uses process data reconciliation according to VDI 2048 to evaluate datasets over a long period covering different operating conditions of the cooling tower. Data reconciliation is a statistical method to determine the true process parameters with a statistical probability of 95% by considering closed material-, mass-and energy balances. Datasets which are not suitable for the evaluation due to strong transient gradients are excluded beforehand, according to well-defined criteria. The reconciled cold-water temperature is then compared, within a wet bulb temperature range of 5 deg. C to 20 deg. C to the manufacturer's guaranteed temperature. Finally, if the average deviation between reconciled and guaranteed value over the evaluated period is below zero, the cooling tower guarantee is fulfilled. (authors)
Local precipitation increases caused by scavenging of cooling tower plumes
International Nuclear Information System (INIS)
Quantitative estimates are provided of the precipitation increase in the vicinity of wet cooling towers as a result of plume-droplet scavenging by natural rain. Rain rates from 1 to 5 mm/hr and wind speeds of 1 to 10 m/s are considered with source strength equal to moisture flux from a 1000-MW(e) power capacity. The increase in precipitation strongly depends on distance from the tower, wind speed, natural precipitation rate, source strength, and horizontal angle of plume spread. Under favorable conditions of light winds and steady rainfall, precipitation increases due to scavenging up to about 25 percent of the natural rate should occur as far as 1 km from plants as small as 1000 MW
Rainfall enhancement due to scavenging of cooling tower condensate
International Nuclear Information System (INIS)
Estimates of rainfall enhancement resulting from scavenging of cooling tower condensate droplets were made using relevant aerosol scavenging theory and a range of meteorological conditions. For a large natural-draft tower, releasing 1.7 x 105 g/sec of condensate, plume centerline rainfall enhancement is predicted to be measurably high at downwind distances between 100 m and 1 km for moderate wind speeds and rainfall rates. The cumulative removal of condensate by scavenging should be significant, even in a light rain (1 mm/hr), where removal half-distances are predicted to be 2.5, 10, and 20 km for wind speeds of 1, 5, and 10 m/sec, respectively
Experience with the operation during winter of wet cooling towers with a varied concept of the main cooling system
International Nuclear Information System (INIS)
On the basis of experience gained from cooling towers in operation it is prudent to operate 'in advance' new cooling towers in accordance with the load and air temperature to be expected. Experience during winter operation, which influences the design of new installations, has been accumulated from the cooling towers at Philippsburg and Grohnde nuclear power stations and also from those at the district heating power plant of Volkswagen at Wolfsburg. The measures taken cannot and should not totally prevent ice formation; however, with future expected methods of operation of cooling towers it is possible to foresee uninterrupted operation during winter. (orig.)
Thermal investigation of ETRR-2 research reactor with different induced draft wet cooling tower
International Nuclear Information System (INIS)
The thermal performance of nuclear reactor is directly affected by its cooling system. The cooling tower plays an important role in this cooling system to evacuate the heat generated in the nuclear reactor core. In this work simple mathematical model is used to compare a two cooling towers; the first cooling tower which operated in the reactor till 2003 and the second one (current) which replaced the first.in 2003, to predict a core inlet temperature and a cooling tower outlet temperature. The effect of ambient condition on the performance is measured. An Engineering Equation Solver program (EES) is used to simulate the integrated cooling system and the model is validated by readings from control room monitors in the reactor. The results showed better performance of the present cooling tower
Physical quantities related to measurement campaigns for cooling towers
International Nuclear Information System (INIS)
The nomenclature in reports on the measurement campaigns for cooling towers will be adapted as far as possible to the already existing VDI report on this subject. On the other hand, the appropriate standards will also be accounted for. In order to facilitate a decision in individual cases in a first table the meteorologically or generally interesting quantities of the VDI reports are compared with the German, international, and WMO standards and - if necessary - also commented. A second table contains the air humidity parameters standardized by WMO including brief definitions. (orig/HP)
Wind pressure distribution in a hyperbolic cooling tower
International Nuclear Information System (INIS)
Results of a wind tunnel study of the wind pressure distribution on a hyperbolic cooling tower 133m high and base diameter of 122m are prese nted. Measurements of wind pressure were made at 16 external and 8 internal levels. The base columns as well as the heat exchangers were reproduced in the model. The heat exchanger caused a small alteration on the overall distribution of the external and internal pressures, with the exception of the region on the wake near the shell bottom where the internal suction was substantially smaller in the model without heat exchanger. (Author)
Heat rejection enhancement in natural draft cooling tower using radiator-type windbreakers
International Nuclear Information System (INIS)
Highlights: � Radiator-type windbreakers are more efficient than solid types. � They can improve cooling efficiency by three times of solid types. � Radiator-type windbreakers are efficient even at normal condition. - Abstract: Cooling efficiency of a natural draft dry cooling tower decreases under crosswind condition. Many researchers frequently recommended solid windbreakers to improve the cooling efficiency. The present research work concerns with the cooling performance assessment of the cooling tower under crosswind condition when the windbreakers are fabricated from the same type of cooling tower radiators. Computational fluid dynamics approach based on the finite volume method has been used to assess the cooling performance of the cooling tower. Numerical results show that radiator type windbreakers can substantially more improve the cooling efficiency than the usual solid types do
Effect of column length on buckling factors of R.C. hyperbolic cooling towers
International Nuclear Information System (INIS)
In this research, the bucking of R.C. cooling towers of Shazand power plant as a typical cooling tower has been studied by using VGB recommendations due to wind load. Infinite element analysis ANSYS 5.4 was used. The effect of columns on global buckling of the R.C. cooling towers has been ignored in most codes of practices except ACI. According to this research, in cooling towers with long columns, not only the buckling factors decrease considerably but in the first modes the columns buckle instead of the shell
Optimization of mechanical draft counter flow wet-cooling tower using artificial bee colony algorithm
International Nuclear Information System (INIS)
Research highlights: ? ABC algorithm is used for optimization of counter flow wet-cooling tower. ? Minimizing the total annual cost for specific heat duty is the objective function. ? Six examples are presented to demonstrate the effectiveness of the proposed algorithm. ? The results are compared with the results of GAMS optimization package. ? The ABC algorithm can be modified to suit optimization of other thermal systems. -- Abstract: This study explores the use of artificial bee colony (ABC) algorithm for design optimization of mechanical draft counter flow wet-cooling tower. Minimizing the total annual cost for specific heat duty requirement is considered as objective function. Three design variables such as water to air mass ratio, mass velocity of water and mass velocity of air are considered for optimization. Evaluations of the cooling tower geometry and performances are based on an adaptive version of Merkel's method. Temperature and enthalpy constraints are included in the optimization procedure. Six examples are presented to demonstrate the effectiveness and accuracy of the proposed algorithm. The results of optimization using ABC are validated by comparing with those obtained by using GAMS optimization package. The effect of variation of ABC parameters on the convergence and optimum value of the objective function has also been presented.
Emission of asbestos fibres from natural-draught cooling towers. Pt. 1 and 2
International Nuclear Information System (INIS)
Sampling for the studies reported has been done in a relatively new nuclear power plant with natural-draught, wet cooling tower, and in an older, brown-coal fired power plant with the same type of cooling towers, both towers equipped with internal structures made of asbestos cement. Samples have been taken from the plumes, air in the environment, cooling water receiving tank, make-up water. The samples have been primarily examined for their content of asbestos fibres. The results show that relatively few asbestos is found in the environmental air and in the cooling water receiving tank. Putting it continuously, it can be said that the cooling water entrains only little amounts of the asbestos of the internal structures. The plume samples indicate emission of some thousand asbestos fibres per m3, or less than 1 ng. Taking into account one sample exhibiting an extremely high amount of asbestos, the average emission of asbestos fibres with the plumes is 106 fibres per m3, or 100 ng/m3 of plume. The maximum air pollution thus calculated in accordance with TA Luft (Clean Air Technical Directive), for the less favourable weather conditions at a hight of 2 m above ground, is 10 fibres per one m3 of air; including the extreme data of the single sample mentioned above, the result is some thousand fibres per m3. The data are far below the TRK data (Technical guiding data for maximum concentration at the place of work), which state a maximum of 106 fibres per m3. (orig.)
Towards safe and economic seismic design of cooling towers of extreme height
International Nuclear Information System (INIS)
Nuclear power plants are being increasingly equipped with natural draught cooling towers of heights greater than 160 m. In many arid zones, where high natural draught cooling towers with dry cooling systems are being projected, wind loads are relativelly small while site seismicity is relatively high. Thus the ability of the tower to withstand earthquake induced forces governs its design. On the other hand, most reinforced concrete cooling towers of extreme height built so far were designed to withstand high wind loads and moderate earthquake loads. The effects of special structural measures for obtaining an economic design, such as the introduction of ring stiffened shells, have been studied mainly for those towers. In view of the previous aspects it is the purpose of this paper to analyze the effects of various structural measures and other parameters on the seismic response of such high cooling towers. (orig.)
Study plan for conducting a section 316(a) demonstration: K-Reactor cooling tower, Savannah River Site
International Nuclear Information System (INIS)
The K Reactor at the Savannah River Site (SRS) began operation in 1954. The K-Reactor pumped secondary cooling water from the Savannah River and discharged directly to the Indian Grave Branch, a tributary of Pen Branch which flows to the Savannah River. During earlier operations, the temperature and discharge rates of cooling water from the K-reactor were up to approximately 70 degree C and 400 cfs, substantially altering the thermal and flow regimes of this stream. These discharges resulted in adverse impacts to the receiving stream and wetlands along the receiving stream. As a component of a Consent Order (84-4-W as amended) with the South Carolina Department of Health and Environmental Control, the Department of Energy (DOE) evaluated the alternatives for cooling thermal effluents from K Reactor and concluded that a natural draft recirculating cooling tower should be constructed. The cooling tower will mitigate thermal and flow factors that resulted in the previous impacts to the Indian Grave/Pen Branch ecosystem. The purpose of the proposed biological monitoring program is to provide information that will support a Section 316(a) Demonstration for Indian Grave Branch and Pen Branch when K-Reactor is operated with the recirculating cooling tower. The data will be used to determine that Indian Grave Branch and Pen Branch support Balanced Indigenous Communities when K-Reactor is operated with a recirculating cooling tower. 4 refs., 1 fig. 1 tab
Thermodynamic study of the effects of ambient air conditions on the thermal performance characteristics of a closed wet cooling tower
International Nuclear Information System (INIS)
A thermodynamic model was developed and used to assess the sensitivity of thermal performance characteristics of a closed wet cooling tower to inlet air conditions. In the present study, three cases of different ambient conditions are considered: In the first case, the average mid-winter and mid-summer conditions as well as the extreme case of high temperature and relative humidity, in Athens (Greece) during summer are considered according to the Greek Regulation for Buildings Energy Performance. In the second case, the varied inlet air relative humidity while the inlet air dry bulb temperature remains constant were taken into account. In the last case, the effects on cooling tower thermal behaviour when the inlet air wet bulb temperature remains constant were examined. The proposed model is capable of predicting the variation of air thermodynamic properties, sprayed water and serpentine water temperature inside the closed wet cooling tower along its height. The reliability of simulations was tested against experimental data, which were obtained from literature. Thus, the proposed model could be used for the design of industrial and domestic applications of conventional air-conditioning systems as well as for sorption cooling systems with solid and liquid desiccants where closed wet cooling towers are used for precooling the liquid solutions. The most important result of this theoretical investigation is that the highest fall of serpentine water temperature and lossesof serpentine water temperature and losses of sprayed water are observed for the lowest value of inlet wet bulb temperature. Hence, the thermal effectiveness, which is associated with the temperature reduction of serpentine water as well as the operational cost, which is related to the sprayed water loss due to evaporation, of a closed wet cooling tower depend predominantly on the degree of saturation of inlet air.
Cooling water distribution system
Orr, Richard (Pittsburgh, PA)
A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using an interconnected series of radial guide elements, a plurality of circumferential collector elements and collector boxes to collect and feed the cooling water into distribution channels extending along the curved surface of the steel containment vessel. The cooling water is uniformly distributed over the curved surface by a plurality of weirs in the distribution channels.
Wind effects on optimal aerodynamic conditions for a wet cooling tower with natural draft
International Nuclear Information System (INIS)
Among the problems of an aerodynamic nature, related to the wind action, the two following ones have to be studied through model tests to reach a better knowledge of design and operating conditions of counterflow natural draft wet cooling towers with water recovery systems. - Wind effects on performance. A very general phenomenon. In order to minimize this alteration, a common idea is to install radio windbrake walls. - Wind effects on the forces applied to the internal structures and thermal components. A relatively elaborate model, representative of a lower plenum layout was fitted with a sufficiently large number of pressure tapes to draw up the distribution of the pressure acting upon: - the packing, - the water recovery system, - the windbrake walls (eventually) and for various combination of these elements. The air flow mode in the tower was also observed. All these observations were made with different wind directions. This study showed that the forces were very variable geographically, very sensitive to the layout
A simulation-based method to analyse the behaviour of rc cooling towers shells
International Nuclear Information System (INIS)
This paper deals with numerical simulations undertaken for the service life and maintenance management of EDF cooling towers. Following a presentation of the industrial context and of the numeric tools dedicated to RC structure ageing, two finite element models are presented. The first one aims at simulating the collapse of a tower fallen down in 1979, the second one is devoted to the assessment of damages undergone by cooling towers during the 1999 tempest in France. (authors)
Reuso de efluentes em torres de resfriamento - estudo conceitual: Aeroporto Internacional do Rio de Janeiro = Water reuse for cooling towers � conceptual study: Rio de Janeiro International Airport
Directory of Open Access Journals (Sweden)
Denize Dias de Carvalho
Full Text Available O reuso de �gua � ferramenta valiosa na gest�o da �gua, que promove a otimiza��o da utiliza��o do recurso desta, que reduz e, muitas vezes, at� elimina os impactos no meio ambiente. Neste trabalho foi investigada a composi��o do efluente secund�rio da esta��o de tratamento de efluentes (ETE APOIO do Aeroporto Internacional do Rio de Janeiro, com o objetivo de propor o processo adequado � reutiliza��o deste efluente como �gua de reposi��o nas torres de resfriamento desse Aeroporto. Com base nas an�lises de c�tions, �nions, DBO e DQO, verificou-se o par�metro SDT - Cl- como cr�tico para processamento do efluente. Foi proposta uma sequ�ncia para reutiliza��o do efluente que continha o tratamento de osmose inversa, o custo do m3 produzido por essa sequ�ncia foi estimado em R$ 2,90 m-3. Water reuse is an important tool in water management; it is a conceptthat promotes optimization of the water resource, reducing and often even eliminating environmental impacts. In this work, the composition of a secondary effluent (from the effluent treatment station (ETE APOIO at Rio de Janeiro International Airport was analyzed, with theaim of determining an adequate process for the reutilization of this effluent as replacement cooling water. Chemical analyses such as cation and anion analysis, BOD and COD were performed. Based on these analyses, it was found that TDS - Cl- was the critical parameter foreffluent processing. A treatment system was proposed for effluent reuse including reverse osmosis; the cost estimate per m3 produced by this system was R$ 2.90 m-3.
Energy and exergy analysis of a co current gas cooling tower based on mathematical modeling and simulation results
International Nuclear Information System (INIS)
Beginning with a discussion of energy and exergy analysis definitions, the presented study provides a descriptive mathematical model for energy and exergy analysis for a co current gas cooling tower. For this purpose using conservation laws of mass, energy and momentum, the variation of temperature and enthalpy of gas and liquid streams are predicted along the tower length and are used in order to calculate the energy and exergy efficiencies. The model validity in prediction of gas and liquid characteristics changing along the tower length was examined against some operating data measured in a commercial cement plant. As a result, it was concluded that in spite of high energy efficiency, the cooling tower has a relatively low exergic efficiency which is because of thermodynamic irreversibilities and entropy production during heat and mass transfers. Also, the effect of some operating parameters including tower diameter, tower length, liquid drops size distribution and water flow rate was investigated on amount of exergy destruction. In all cases the results showed that the exergy of water does not completely absorbed by gas and a notable portion of the exergy is destructed. The result of these investigations may be employed to inform about the true energy potential caring by fluids
Experimental buckling investigations of cooling tower shells under wind load
International Nuclear Information System (INIS)
The buckling behavior of cooling tower shells under realistic wind loading are investigated. Buckling tests on elastic modells are carried out in a wind-tunnel. As the first step of these tests, the wind-velocity over height and the distribution of the internal and external pressures are measured. After this, the membrane and bending stresses in the shell are measured by means of electrical strain gages and at the same time the critical wind pressure too. Parameters investigated are the wind load and the stiffening by rings, including the effect of the upper edge beam. The effects of the bending moments on the local critical membrane stresses will be determined and the BSS-Approach will be modified. (orig.)
Fog and drift deposition from evaporative cooling towers
International Nuclear Information System (INIS)
Methods of determining fog and drift deposition due to emissions from evaporative cooling towers are reviewed and formulas suggested that can be used as a basis for calculations. The Gaussian plume formula is recommended for calculating fog concentrations from which visibility can be estimated. For drift droplets with diameters greater than 200 ?m, deposition is calculated by ballistics methods, knowing the environmental wind speed and relative humidity and the vertical velocity of the plume and the droplet. Evaporation of the droplets is accounted for. Drift droplets with diameters less than 200 ?m are assumed to be dispersed according to the Gaussian plume formula, with the plume tilted downward to account for the settling speed of the droplet
Reuse of refinery's tertiary-treated wastewater in cooling towers: microbiological monitoring.
Dos Santos, Vera L�cia; Veiga, Andr�a Azevedo; Mendon�a, Rafael Silva; Alves, Andrea Lima; Pagnin, S�rgio; Santiago, V�nia M J
The study was planned to quantify the distribution of bacteria between bulk water and biofilm formed on different materials in an industrial scale cooling tower system of an oil refinery operating with clarified and chlorinated freshwater (CCW) or chlorinated tertiary effluent (TRW) as makeup water. The sessile and planktonic heterotrophic bacteria and Pseudomonas aeruginosa densities were significantly higher in the cooling tower supplied with clarified and chlorinated freshwater (CTCW) (p?glass slides and stainless steel coupons than on the surface of carbon steel coupons. The average corrosion rates of carbon steel coupons (0.4-0.8 millimeters per year (mpy)) and densities of sessile (12-1.47?�?10(3) colony-forming unit (CFU)?cm(-1)) and planktonic (0-2.36?�?10(3) CFU mL(-1)) microbiota remained below of the maximum values of reference used by water treatment companies as indicative of efficient microbial control. These data indicate that the strategies of the water treatment station (WTS) (free chlorine) and industrial wastewater treatment station (IWTS) followed by reverse electrodialysis system (RES) (free chlorine plus chloramine) were effective for the microbiological control of the two makeup water sources. PMID:25226836
Organohalogens in chlorinated cooling waters discharged from nuclear power stations
International Nuclear Information System (INIS)
For the power plant discharges studied to date, measured concentrations of trihalomethanes are lower than might be expected, particularly in cooling tower water, which can lose THMs to the atmosphere. In the cooling towers, where chlorine was added in higher concentrations and for longer residence times, halogenated phenols can contribute significantly to the total organic halogen content of the discharge. The way in which cooling towers are operated may also influence the production of halogenated phenols because they concentrate the incoming water by a factor of 4 or 5. In addition, the phenols, which act as a substrate for the halogenating agent, are also probably concentrated by the cooling tower operation and may be prevented from being biodegraded by addition of the same biocide that produces the halogenated phenols. 8 references, 4 tables
Numerical simulation of flow field in cooling tower of passive residual heat removal system of HTGR
International Nuclear Information System (INIS)
Environmental wind will influence the working conditions of natural convection cooling tower. The velocity and temperature fields in the natural convection cooling tower of the HTGR residual heat removal system at different environmental wind velocities were numerically simulated. The results show that, if there is no wind baffle, the flow in the cooling tower is blocked when environmental wind velocity is higher than 6 m/s, residual heat can hardly be removed, and when wind velocity is higher than 9 m/s, the air even flow downwards in the tower, so wind baffle is very necessary. With the wind baffle installed, the cooling tower works well at the wind speed even higher than 9 m/s. The optimum baffle size and positions are also analyzed. (authors)
The Merkel coefficient and its dependence on the temperature position of the cooling tower process
International Nuclear Information System (INIS)
The Merkel coefficient, or evaporation coefficient, is still being used as a characteristic factor for the cooling tower process. Its dependence on the cooling range or on the warm water temperature of the process is often considered a disadvantage of the theory of evaporation cooling. This is also the reason for the suggestion to change the theory in such a way that the Merkel coefficient becomes independent of the temperature. The present investigation, however, leads to the result that the dependence of the Merkel coefficient on the temperature must be considered as a remarkable confirmation for the evidence of the theory of heat and mass transfer, as the experimental statements agree fully with the results of the theoretical considerations. (orig.)
The Center for the Advancement of Process Technology presents this free sample module on cooling water systems in the process industry. The material includes 21 slides and will help learners understand related terms, the purpose of the basic equipment involved in cooling water systems and the safety, health and environmental concerns involved with these systems.
Exergy transfer and parametric study of counter flow wet cooling towers
International Nuclear Information System (INIS)
A thermodynamic analysis of the counter flow wet cooling tower (CWCT) is performed in this paper. Both energy and exergy formulations are developed and validated for the system. Four types of exergy transfer processes occurring inside the CWCT are investigated schematically. A parametric study is conducted under various operating conditions in order to investigate the effects of thermal efficiency and water-to-air ratio on the exergy performance of the CWCT. Unlike past studies, the transiting exergy contained in the inlet and outlet water is not considered. It is found that the exergy efficiency is always less than 25%. The exergy parameters including evaporation water loss, exergy efficiency, exergy input, internal and external exergy losses are very sensitive to the thermal efficiency when it is very close to 1.0 at lower water-to-air ratios. - Research highlights: ? We model counter flow wet cooling towers and make a detailed exergy analysis. ? Four types of exergy transfer processes are investigated schematically. ? Only a small part of exergy input, less than 25%, is effectively utilized.
Suppression pool water cooling system
International Nuclear Information System (INIS)
In a suppression pool water cooling system for cooling pool water stored in a suppression pool of a BWR type nuclear reactor, pool water cooling coils are contained in the suppression pool and cooling pipeways are connected to the cooling coils for guiding cooling water such as sea water or fresh water. This enables to directly cool the pool water in the suppression pool to improve the cooling efficiency. Further, the consititution of the cooling system can be simplified remarkably to make the operation control procedures convenient and easy for the cooling system. (T.M.)
Report on accompanying measurements concerning the investigation into micro-organism discharge from the cooling tower facility of the Isar nuclear power plant
International Nuclear Information System (INIS)
The report gives the thermal marginal conditions for micro-organism discharge measurements which, on the whole, are very similar throughout the whole period of time. Parameters i.e. meteorology, temperatures of cooling water at cooling-tower entry and exit, temperature of the liquid-water loads of the plumes as well as mass flows of the cooling water are needed for allocating microbiological measurements. Measurement of droplet discharge can be used for checking guaranteed value. (DG)
Ultimate strength of R/C cooling tower shells subjected to wind load
International Nuclear Information System (INIS)
The failure mechanisms of the R/C cooling tower shells subjected to the dead load and the wind load are examined by use of the finite element method. Also adopting two types of imperfection, bulge type and ring type, the effects of initial imperfections of the ultimate strength of the R/C cooling towers are analyzed numerically. It is concluded that the tension stiffening of the cracked concrete plays the important role to the ultimate strength of the R/C cooling tower shells and that the ultimate strength of the hyperbolic R/C shells is not sensitive to the initial imperfection. (author)
Maintenance of cooling towers following two outbreaks of Legionnaires' disease in a city.
Bhopal, R. S.; Barr, G.
This survey assessed the maintenance of evaporative cooling towers in Glasgow, following two Legionnaires' disease outbreaks. Information was obtained from 76 of 81 premises and a maintenance score was calculated for each of 174 towers. The quality of maintenance was extremely varied (range of maintenance scores, 8-30; mean, 22 (S.D., 5.0); median, 23; maximum possible, 33) and some towers were neglected. Breaches of maintenance principles were mainly structural and organizational, e.g. inade...
40 CFR 749.68 - Hexavalent chromium-based water treatment chemicals in cooling systems.
...water. (12) Industrial cooling tower...remove heat from industrial processes, chemical reactions, or plants producing electrical...Prohibition of distribution in commerce and...chemicals in, industrial cooling...
Numerical modelling of cooling tower plumes: comparison with experimental data
International Nuclear Information System (INIS)
To validate the numerical models of cooling tower plumes used in impact studies, EDF has effected a major testing program in the vicinity of the BUGEY nuclear power station, including sets of fine measurements taken from aircraft, teledetection readings and routine measurements effected over a very period (photographs of plumes, micro-meteorological network). The data recorded have allowed two types of models to be validaded: 1) The aim of the first type is to establish statistics of the morphological characteristics of plumes (length, height, etc.) and the resulting micro-climatic changes (i.e. reduction of the duration of sunshine and attenuation of the intensity of overall radiation. This type of model was validated on the basis of the routine measurements carried out over a long period. 2) The second type (a three - dimensional model and a microphysical model of the spectrum), mainly designed for the study of the dynamic and thermodynamic structure of plumes, has been validated on the basis of measurements made during intensive measurements campaigns (formation of artificial cumulus, interaction of the plume with a cloud formation)
Static Limit Load of a Deteriorated Hyperbolic Cooling Tower
International Nuclear Information System (INIS)
Irregular concrete erosion due to atmospheric and industrial effects is assessed by a layer model of reinforced concrete shells by simply removing the deteriorated layers. Concrete tension strength and fracture energy become very important properties in these circumstances since reinforcement bars are locally ineffective. A material model for cracking reinforced concrete is suggested and an application is presented to the ultimate load analysis of a natural draught cooling tower. Both geometric and material non-linearities are accounted for. In particular, the geometric instability is identified in the process of incremental wind load (static loading) which occurs locally due to the loss of cross-section and degradation of concrete strength. Strain softening in concrete is significant in this context since the associated cross-section stiffness decrease affects the limit load. The finite element model and material models of concrete and reinforcement enable reliable deterministic limit load analysis. The ratio of the limit load to actual service load thus obtained is about 1.5. The actual safety margin can only be assessed by a stochastic reliability analysis. This is intended using the Hasofer-Lind reliability index. (authors)
The influence of atmospheric conditions on the cooling tower plume of nuclear power station
International Nuclear Information System (INIS)
The paper deals with the effect of atmospheric conditions - relative humidity, wind velocity, temperature and temperature gradient on the visible plume. For estimating cooling tower plumes, used was made of verified mathematical model. (author)
Geodetic works on the construction of cooling tower of TE� 6
Kolari?, Andrej
The thesis discusses with geodetic works on the construction of cooling tower of sixth block in �o�tanj thermal power plant. It presents briefly the thermal power plant and describes the process of construction of the cooling tower. The establishment of basic surveying network stakeout is explained. It is also contains a full description of the stakeout procedures. Paper states the requirements and accuracy of stakeout and describes practical examples. It shows the concrete implementation ...
Climatic uncertainty in Himalayan water towers
Mishra, Vimal
The Himalayan water towers (e.g., Indus, Ganges, and Brahmaputra) play a major role in water resource availability and affect a significant population in the South Asia region. Climatic uncertainty in the region not only hampers progress toward process understanding but also decision making. Observational data sets show uncertainty (standard deviation in mean temperature in data sets) of 0.2 to 0.5�C in winter (January-February-March-April) and the monsoon season (June-July-August-September) air temperature. Observational uncertainty in precipitation in the winter and monsoon seasons ranged between 6 and 17% (with respect to ensemble mean seasonal precipitation) in the Indus, Ganges, and Brahmaputra river basins. The Coordinated Regional Climate Downscaling Experiment (CORDEX) South Asia regional climate models (CORDEX-RCMs) show larger uncertainty (1-3.6�C in temperature and 18-60% in precipitation) than that of the observations. Moreover, RCMs exhibit a large cold bias (6-8�C) and are not able to reproduce the observed warming in the Himalayan water towers. In fact, the CORDEX-RCMs overestimate observed warming by threefold in Ganges and Brahmaputra basins, which raises a question on their reliability on future warming trends in the region. The CORDEX-RCMs overestimate the area that experienced significant warming and fail to reproduce precipitation trends in both magnitude as well as direction. In observational data sets, uncertainty in precipitation and air temperature increases with elevation, which may be associated with sparse observations. However, the CORDEX-RCMs showed larger uncertainty at the lower elevations in both precipitation as well as temperature. The host general circulation models show a better performance in simulating winter climate than the CORDEX-RCMs, which suggest that an improved representation of elevation may not necessarily improve the model's performance. While observations show significant warming in the Indus basin and decline in the monsoon season precipitation in the Ganges basin, reliability of future climate projections and their impacts on water resources in the region will depend on improvements in the models and observations in coming years.
Conversion of water towers � an instrument for conserving heritage assets
Directory of Open Access Journals (Sweden)
Andreea-Loreta Cercleux
Full Text Available Water towers are symbolical landmarks that refer to the industrialization. The oldest water towers are technical and industrial assets whose current and future evolution is a sensitive matter as a result of the economic context that brought about the closing of numerous industrial enterprises and abandoning infrastructure assets, including water towers. Some water towers were included on the national cultural-heritage lists across the world, thanks to the manifold values they incorporate (technological, historical, architectural, esthetical, among others. In this context, it has become necessary to convert them, with the twofold purpose of conserving them and assigning them a new function, for the local community members. Although there are numerous models for good practice in the conversion of water towers in several European countries, in Romania their reuse is a difficult process, most of the time burdened by shortcomings of legislation or lack of financial support. The study�s main purpose is to present reasons for the conversion of water towers and to highlight several good practice models, as well as to present several water towers with a high potential for conversion.
Reinforced concrete column- supported by hyperboloid cooling tower stability assessment for seismic loads
International Nuclear Information System (INIS)
In recent years, the use of larger reinforced concrete column-supported hyperboloid cooling towers has been increased significantly. Thus, the investigation on failure criteria for structural components of such structures under different loads has been found as an essential need. Construction of cooling towers in seismic zones initiated the study on the dynamic behavior of such structures due to seismic loads. In this paper, finite element analyses have been performed to obtain the stress concentration, nonlinear behavior, stability or safety factor of the R. C. tower due to earthquakes loads. Outcomes of the study show that considerable plastic hinges were created in the X shape long columns of the R.C. hyperboloid cooling tower due to seismic loads, which resulted in a significant decrease in the stability safety factor and, an increase in concerns
Assessment of cooling tower (ultimate heat sink) performance in the Byron individual plant examination
International Nuclear Information System (INIS)
A time-dependent model of the Byron Nuclear Generation Station safety-related cooling towers has been developed for use with the Byron PRA (IPE). The model can either be run in a stand-alone program with externally supplied heat loads, or can be directly coupled into MAAP (Modular Accident Analysis Program). The primary feature of the model is a careful tracking of the basin temperature through the progression of different severe accidents. Heat removal rates from containment, both from containment fan-coolers and the residual heat removal system, are determined by the feed-back of this time-varying return temperature. Also, the inventory of the basin is tracked in time, and this is controlled by make-up, evaporative losses due to the heat load supplied to the towers, and the possibility of unsecured blowdown. The model has been used to determine the overall capabilities and vulnerabilities of the Byron Ultimate Heat Sink (UHS). It was determined that the UHS is very reliable with respect to maintaining acceptably low basin temperatures, requiring only at most two of eight operating cooling tower fans. Further, when the two units have their Essential Service Water (ESW) systems cross-tied, one of four ESW operating pumps is sufficient to handle the loads from the accident unit with the other unit proceeding to an orderly shutdown. The major vulnerability of the Byron UHS is shown to be the ability to maintain inventory, although the time-scales for basin dry-out are relatively long, being eight to twenty-one hours, depending upon when blowdown is secured. (author)
International Nuclear Information System (INIS)
LHC experiments demand on cooling of electronic instrumentation will be extremely high. A large number of racks will be located in underground caverns and counting rooms, where cooling by conventional climatisation would be prohibitively expensive. A series of tests on the direct water cooling of VMEbus units and of their standard power supplies is reported. A maximum dissipation of 60 W for each module and more than 1000 W delivered by the power supply to the crate have been reached. These values comply with the VMEbus specifications
Dumont, G.; Fontaine Vive Roux, Ph.; Righini, B.
LHC experiments demand on cooling of electronic instrumentation will be extremely high. A large number of racks will be located in underground caverns and counting rooms, where cooling by conventional climatisation would be prohibitively expensive. A series of tests on the direct water cooling of VMEbus units and of their standard power supplies is reported. A maximum dissipation of 60 W for each module and more than 1000 W delivered by the power supply to the crate have been reached. These values comply with the VMEbus specifications.
Dumont, G; Righini, B
LHC experiments demand on cooling of electronic instrumentation will be extremely high. A large number of racks will be located in underground caverns and counting rooms, where cooling by conventional climatisation would be prohibitively expensive. A series of tests on the direct water cooling of VMEbus units and of their standard power supplies is reported. A maximum dissipation of 60 W for each module and more than 1000 W delivered by the power supply to the crate have been reached. These values comply with the VMEbus specifications. (3 refs).
On cooling-water systems design for South African industry: Two recent developments
Scientific Electronic Library Online (English)
Thokozani, Majozi; Nongezile, Nyathi.
Full Text Available This paper presents two recent developments in the targeting and design of cooling-water systems using process integration. The basis of this work is the observation that true optimization of any cooling-water system, comprising a cooling tower and a network of operations that use cooling water, can [...] be realized only by considering the system as a whole. Traditional approaches have focused separately on either the cooling tower or the operational network. Optimality, in the context of this paper, refers to minimum cooling-water flowrate to the network or maximum return temperature to the source of the cooling water (a cooling tower). Only systems with at least two cooling towers instead a single one are considered here, to highlight the complexity of a typical cooling-water system. The first exercise is based on a graphical technique in which targeting for the minimum cooling water precedes design of the cooling-water network to achieve the target. The second exercise uses mathematical modelling to optimize a superstructure that entails all possible topological arrangements of the cooling-water network. An industrial case study involving a South African explosives manufacturing plant is used to demonstrate the effectiveness of both techniques. Cooling-water savings of more than 20% were realized with modest capital investment.
Wind tunnel experimental study on effect of inland nuclear power plant cooling tower on air flow and dispersion of pollutant
International Nuclear Information System (INIS)
A wind tunnel experiment for the effect of the cooling tower at Taohuajiang nuclear power plant on air flow and dispersion of pollutant was introduced in paper. Measurements of air mean flow and turbulence structure in different directions of cooling tower and other buildings were made by using an X-array hot wire probe. The effects of the cooling tower and its drift on dispersion of pollutant from the stack were investigated through tracer experiments. The results show that the effect of cooling tower on flow and dispersion obviously depends on the relative position of stack to cooling towers, especially significant for the cooling tower parallel to stack along wind direction. The variation law of normalized maximum velocity deficit and perturbations in longitudinal turbulent intensity in cooling tower wake was highly in accordance with the result of isolated mountain measured by Arya and Gadiyaram. Dispersion of pollutant in near field is significantly enhanced and plume trajectory is changed due to the cooling towers and its drift. Meanwhile, the effect of cooling tower on dispersion of pollutant depends on the height of release. (authors)
System approach to calculated grounding of reliability of new designs for cooling towers with metal frame
International Nuclear Information System (INIS)
Dealt with are the methods of the system approach to reliable grounding of new design features of cooling towers with the metal frame. The new design of prestressed ferroconcrete shells is presented. It provides considerable saving in specific amount of material per structure and labor input for manufacturing. The problems to be solved by the researchers, designers builders and operating staff are stated on the basis of the system approach. Successful solution of these problems will provide reliability of the structure. An example of the system approach to the design of a guy rope cooling tower is given
Energy Technology Data Exchange (ETDEWEB)
Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Holloway, Michael Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pulliam, Elias Noel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
This design is intended to replace the current mirror setup being used for the NorthStar Moly 99 project in order to monitor the target coupon. The existing setup has limited movement for camera alignment and is difficult to align properly. This proposed conceptual design for a water cooled mirror will allow for greater thermal transfer between the mirror and the water block. It will also improve positioning of the mirror by using flexible vacuum hosing and a ball head joint capable of a wide range of motion. Incorporating this design into the target monitoring system will provide more efficient cooling of the mirror which will improve the amount of diffraction caused by the heating of the mirror. The process of aligning the mirror for accurate position will be greatly improved by increasing the range of motion by offering six degrees of freedom.
Use of Air2Air Technology to Recover Fresh-Water from the Normal Evaporative Cooling Loss at Coal-Based Thermoelectric Power Plants
Energy Technology Data Exchange (ETDEWEB)
Ken Mortensen
This program was undertaken to build and operate the first Air2Air{trademark} Water Conservation Cooling Tower at a power plant, giving a validated basis and capability for water conservation by this method. Air2Air{trademark} water conservation technology recovers a portion of the traditional cooling tower evaporate. The Condensing Module provides an air-to-air heat exchanger above the wet fill media, extracting the heat from the hot saturated moist air leaving in the cooling tower and condensing water. The rate of evaporate water recovery is typically 10%-25% annually, depending on the cooling tower location (climate).
Experimental study regarding the evolution of temperature profiles inside wet cooling tower under cross-wind conditions
International Nuclear Information System (INIS)
Based on similarity theory, this research details a thermal-state model experiment, concerning the evolution of the air/water temperature profiles inside a Natural Draft Wet Cooling Tower (NDWCT) under windless and cross-wind conditions. Prior studies have shown that the air/water temperature distribution is fairly uniform and stable under windless (stagnant) conditions, but the uniformity is destroyed in the presence of windy conditions, and the air/water temperature of different points displays a large variation subject to the same cross-wind velocity. Generally speaking, the highest air/water temperature values inside the whole tower lie on the windward and leeward direction, but the highest air temperature at the tower outlet appears near the leeward side zone, rather than exactly on the leeward side. Based on this research, the air/water temperature profiles regarding measurement of values can be obtained accurately under windless and cross-wind conditions, a fact that can help confirm the specific location of vortex on the windward and leeward side. All of above findings can provide an important theoretical foundation concerning further research, specifically for energy-saving aspects NDWCTs. (authors)
Thermoelectrically cooled water trap
Micheels, Ronald H. (Concord, MA)
A water trap system based on a thermoelectric cooling device is employed to remove a major fraction of the water from air samples, prior to analysis of these samples for chemical composition, by a variety of analytical techniques where water vapor interferes with the measurement process. These analytical techniques include infrared spectroscopy, mass spectrometry, ion mobility spectrometry and gas chromatography. The thermoelectric system for trapping water present in air samples can substantially improve detection sensitivity in these analytical techniques when it is necessary to measure trace analytes with concentrations in the ppm (parts per million) or ppb (parts per billion) partial pressure range. The thermoelectric trap design is compact and amenable to use in a portable gas monitoring instrumentation.
A model for radionuclide transport in the Cooling Water System
International Nuclear Information System (INIS)
A radionuclide transport model developed to assess radiological levels in the K-reactor Cooling Water System (CWS) in the event of an inadvertent process water (PW) leakage to the cooling water (CW) in the heat exchangers (HX) is described. During and following a process water leak, the radionuclide transport model determines the time-dependent release rates of radionuclide from the cooling water system to the environment via evaporation to the atmosphere and blow-down to the Savannah River. The developed model allows for delay times associated with the transport of the cooling water radioactivity through cooling water system components. Additionally, this model simulates the time-dependent behavior of radionuclides levels in various CWS components. The developed model is incorporated into the K-reactor Cooling Tower Activity (KCTA) code. KCTA allows the accident (heat exchanger leak rate) and the cooling tower blow-down and evaporation rates to be described as time-dependent functions. Thus, the postulated leak and the consequence of the assumed leak can be modelled realistically. This model is the first of three models to be ultimately assembled to form a comprehensive Liquid Pathway Activity System (LPAS). LPAS will offer integrated formation, transport, deposition, and release estimates for radionuclides formed in a SRS facility. Process water and river water modules are forthcoming as input and downstream components, respectively, for KCTA
Phototrophic biofilms on the interior walls of concrete Iterson-type cooling towers.
Czech Academy of Sciences Publication Activity Database
Hauer, Tom�
Ro?. 22, ?. 6 (2010), s. 733-736. ISSN 0921-8971 R&D Projects: GA ?R GA206/08/0318 Institutional research plan: CEZ:AV0Z60050516 Keywords : cyanobacteria * algae * cooling towers Subject RIV: EF - Botanics Impact factor: 1.792, year: 2010
Cooling tower drift study at the Oak Ridge Gaseous Diffusion Plant
International Nuclear Information System (INIS)
The environmental study of cooling towers at the ORGDP was continued in 1978. The first investigation conducted in 1973 provided valuable first hand information on drift from two cooling tower cells at ORGDP; however, the drift percentage of 0.1% measured in that test appeared to be high. The 1978 drift study was planned and performed to more closely define the drift phenomenon of the cooling tower complex. The cooling tower cells were involved in the test with drift and ground deposition measurements being performed simultaneously. The average drift percentage measured in this test was 0.03% with acceptable agreement among the ten cells tested. The downfield deposition measurements of chromium supported the deposition findings of the 1973 study. The results of the 1978 studies are considered more reliable than those obtained in 1973 because of the greater mass of data obtained from a greater number of tested cells. The results also indicated that the sensitive paper method with its large sampling volume provides more reliable source characteristics information than the optical measuring device with a very small sampling volume
Transition to a new generation of large natural-draught cooling towers
International Nuclear Information System (INIS)
A concept of a new generation of natural-draught cooling towers for large nuclear power plant units is presented considering optimization and calculation methods, safety philosophy, dimension criteria, constructional measures, building materials, construction surveying, climbing formwork, and climbing cranes. The first installation will be available by 1990, with a unit 250 m in diameter by 150 m high
A simplified modeling of mechanical cooling tower for control and optimization of HVAC systems
International Nuclear Information System (INIS)
This paper proposes a new, simple, yet accurate mechanical cooling tower model for the purpose of energy conservation and management. On the basis of Merkel's theory and effectiveness-NTU method, the model is developed by energy balance and heat, mass transfer analysis. Commissioning information is then used to identified, only three model parameters by Levenberg-Marquardt method. Compared with the existing models, the proposed model has simple characteristic parameters to be determined and without requiring iterative computation when the operating point changes. The model is validated by real operating data from the cooling towers of a heating, ventilating and air conditioning (HVAC) system of a commercial hotel. The testing results show that the performance of the cooling tower varies from time to time due to different operating conditions and the proposed model is able to reflect these changes by tuning its parameters. With this feature, the proposed model can be simply used and accurately predict the performance of the real-time operating cooling tower
Water-Cooled Optical Thermometer
Menna, A. A.
Water-cooled optical probe measures temperature of nearby radiating object. Intended primarily for use in silicon-growing furnace for measuring and controlling temperatures of silicon ribbon, meniscus, cartridge surfaces, heaters, or other parts. Cooling water and flushing gas cool fiber-optic probe and keep it clean. Fiber passes thermal radiation from observed surface to measuring instrument.
International Nuclear Information System (INIS)
The pressure vessel is divided by a transverse separating wall above the core into a high pressure and a low pressure plenum chamber. The cooling water flows vertically from below upwards through the core, so that hydraulic lifting forces act on the core. To compensate for these forces a core holding down device, consisting of a pressure piston system is provided. The piston surface is at the pressure of the upper high pressure plenum chamber, while the piston rod acts through the separating wall inside a sealing cylinder on the fuel elements in the core. (DG)
International Nuclear Information System (INIS)
In the reactor operating with supercritical pressure and temperature part of the water flowing through the moderator tubes is deflected at the outlet and mixed with a residual partial flow of the coolant fed into the core as well as passed along the fuel rods in opposite direction. By special guiding of the flow downward through the guide tubes of the control rods insertion of the control rods is simplified because of reduced frictional forces. By this means it is also achieved to design less critical the control rod cooling with respect to flow rate control and operating behavior in case of a scram. (orig.)
Joint summarized report of DFK on the safety of the French Cattenom nuclear power station and the German Philippsburg 2 nuclear power station and appendix: Cooling tower effects
International Nuclear Information System (INIS)
The comparison of the investigations carried out in West Germany and in France, which agree in their statements on the propagation behaviour of cooling tower plumes and the associated environmental effects, shows that in both cases possible effects from cooling towers are limited in space and cannot be proved at a distance of several kilometres from the cooling towers. (orig./HP)
Mathematical model of drift deposition from a bifurcated cooling tower plume
International Nuclear Information System (INIS)
Cooling tower drift deposition modeling has been extended by including centrifugal force induced through plume bifurcation in a crosswind as a mechanism for drift droplet removal from the plume. The model, in its current state of development, is capable of predicting the trajectory of a single droplet from the stage of strong interaction with the vortex field soon after droplet emission at the tower top through the stage of droplet evaporation in an unsaturated atmosphere after droplet breakaway from the plume. The computer program developed from the mathematical formulation has been used to explore the dependency of the droplet trajectory on droplet size, vortex strength, point of droplet emission, drag coefficient, droplet efflux speed, and ambient conditions. A specific application to drift from a mechanical-draft cooling tower (for a wind speed twice the efflux speed, a relative humidity of 70 per cent, and an initial droplet radius of 100 ?m) showed the droplet to follow a helical trajectory within the plume, with breakaway occurring at 2.5 tower diameters downwind and ground impact of the droplet (reduced through evaporation to 55 ?m radius) at 11 tower diameters
Wind tunnel experiments on cooling tower plumes. Pt. 2
International Nuclear Information System (INIS)
The basic characteristics of plumes issuing into a boundary layer type of cross flow are reported. The flow can be considered as an interaction between two vorticity fields with different length scales and turbulence intensities. The large eddies of the oncoming boundary layer are responsible for the observed sudden changes in the plume direction. The type of structures emanating the tower depends on the instantaneous velocity ratio. Mean velocities and normal velocity gradients are smaller than in the case of uniform cross-flow (Andreopoulos, 1986) and therefore the measured turbulence intensities were lower too. The cross-stream turbulence brings high momentum fluid into the wake region and the velocity defect decays very rapidly. Dilution of the plumes takes place faster in the presence of external turbulence than in the case with uniform cross-flow. The spreading rate is increased dramatically by the external turbulence which causes different effects on the hydrodynamic and thermal fields. (orig.)
Evaluation of the effect of cooling towers on the transfer to the ground environment of the tritium from a receiving stream
International Nuclear Information System (INIS)
The studies on the impact of the cooling towers (mechanical draught) of the Tihange-1 Nuclear Power Plant, started in 1978. The first study dealt with the evaluation of the transfer in the terrestrial environment of the tritium released in the Meuse River, upstream of the NPP. This study involved, in 1978, four campaigns of plants exposure of one month duration each, two with the cooling towers in operation and two without. In 1979, three campaigns were performed, one with the towers in operation. The results of measurement of the tritium content of the Meuse water, rainwater, water vapor in air as well as the tissue free water (TFWT) of the plants cultivated in the 9 stations have shown that there was no influence, except in one case, due to the operation of the towers, on the levels of TFWT in the exposed plants. Besides, the comparison of the ratios of the specific activities (OBT plant THO rain) does not show a significant difference between the plants, neither between the stations, with or without the towers operating. One sees nevertheless that this ratio has a value ranging from 2.7 to 7.0 which means that an organic 3H source is available for the plant, this does not seem to be the substratum. On the other hand, the OBT contents of the foliage of trees growing on the site and of algae growing in a pond receiving the water from the Meuse are about the same as the values observed in the plants grown at the stations. On the contrary the OBT content of tions. On the contrary the OBT content of algae growing in the cooling towers are significantly higher (3 to 9 times), which would indicate the presence in the Meuse Water of tritiated organic molecules biologically available. (author)
Spreading of cracks in R. C. hyperbolic cooling towers with and without imperfection due to weight, thermal and wind loads
International Nuclear Information System (INIS)
Imprecise construction work might cause imperfection in the shell of R.C.hyperbolic cooling towers. The cooling towers with large imperfection could collapse due to wind load. The aim of this research is to study the cracks spreading in the shell of a typical R.C. cooling tower with and without imperfection. In Finite Element analysis reinforce bars with nonlinear behavior and solid elements were used. The solid elements which were used in this analysis could crack in three directions. The study on the sample cooling towers showed that deformations and crack spreading differ in the cooling tower shell with and without imperfection due to weight and thermal loads. At he end of the weight and thermal loads, vertical cracks were seen all over the outer side of the perfect shell and intermittent horizontal cracks happened in the shell of cooling tower where it had : its minimum thickness. On the other hand, in an imperfect shell, intermittent vertical and horizontal cracks were seen on the outside of the cooling tower shell due to the weight and thermal loads. When wind loads was added to the weight and thermal loads, the cracks spreading was seen to be similar for both perfect and imperfect R.C. Shell
Cooling clothing utilizing water evaporation
DEFF Research Database (Denmark)
Sakoi, Tomonori; Tominaga, Naoto
We developed cooling clothing that utilizes water evaporation to cool the human body and has a mechanism to control the cooling intensity. Clean water was supplied to the outer surface of the T-shirt of the cooling clothing, and a small fan was used to enhance evaporation on this outer surface. To prevent wet discomfort, the T-shirt was made of a polyester material having a water-repellent silicon coating on the inner surface. The chest, front upper arms, and nape of the neck were adopted as the cooling areas of the human body. We conducted human subject experiments in an office with air temperature ranging from 27.4 to 30.7 �C to establish a suitable water supply control method. A water supply control method that prevents water accumulation in the T-shirt and water dribbling was validated; this method is established based on the concept of the water evaporation capacity under the applied environment.
The maintenance and Repair of the Secondary Cooling Tower Operation of the HANARO for Ten years and Vibration Analysis of the Cooling Fan
International Nuclear Information System (INIS)
The HANARO is a multi-purpose reactor, 30MWth open-tank-in-pool type. Since the HANAO started the critical operation in 1995, it has been normally in operation at present. Heat generated by nuclear fission during the operation of the HANARO is absorbed by the primary coolant and is transmitted to the secondary coolant. The secondary coolant which passes through the cooling tower by means of the circulating pump is refrigerated by the heat exchanger with atmospheric air when the cooling fan operates. In order to operate the HANARO safely, it is essential for the cooling tower to have the sufficient cooling ability. Therefore, the records about maintenance and repair of the cooling tower were analyzed in detail to prevent the failure of the cooling tower in advance. Finally, the cooling tower of the HANARO has a good condition at present and the analysis in maintenance and repair of the cooling tower can be used as the operation data to have the cooling ability for the future
Modified technique of in-place fungicide treatment of cooling towers as used at the Paducah Gaseous Diffusion Plant
International Nuclear Information System (INIS)
A modified technique of in-place fungicide treatment of cooling towers has been developed by Union Carbide Corporation, Paducah, Kentucky. The technique enables the fungicide user to treat towers safely without endangering the personnel applying the fungicide. The technique is time saving and effective in obtaining complete coverage of the plenum areas and the decking
Tracking of smokestack and cooling tower plumes using wind measurements at different levels
International Nuclear Information System (INIS)
Relationships between cooling tower and smokestack plumes at the Bowen Electric Generating Plant in northwestern Georgia and wind direction measurements at levels from the surface at 850 mb (approx. 1.5 km) are examined. The wind measurements play an important role in estimating plume directions which in turn are utilized to establish control and target (upwind and downwind) areas for a study of plant-induced precipitation modification. Fifty-two plume observations were made during a three week period in December 1979. Results indicate that a windset (4.5 km from the plant) mounted at a level approximating that of the cooling tower plume is a better predictor of plume direction than surface windsets (1.0 km from the plant) or 850 mb level winds. However, an apparent topographical influence on the wind direction measurements at the plume-level windset site somewhat limits its plume tracking capability, at least for ambient winds from the SW quadrant
Directory of Open Access Journals (Sweden)
Full Text Available Vibration and cross wind pressure are suspected as the major reason for the failure of the gear box of the cooling tower fan. Also, Vibration suppression of rotating machinery is an important engineering problem. In the present thesis work, I have done a study of the mathematical modeling of gear box of cooling tower fan, target setting for vibration & noise refinement in a system, and investigated various modes of active & passive vibration control techniques. This thesis presents a novel approach to determine the noise and vibration characteristics by predicting the vibration response of a rotating mechanism through data obtained by vibration simulation of a CAD model. Vibration analysis is widely used in industry for condition monitoring of a variety of machines and components. The simulation is then compared to a real-life testing & the 2 results are compared. The experiments are performed for pre-determined loading conditions.
Tests on shell models of cooling towers made of composite materials
International Nuclear Information System (INIS)
This paper presents the buckling tests carried out by Electricite de France (EDF) on cooling tower shell models. High safety factors are imposed in the design for shell buckling (local and global). In order to obtain more realistic values, EDF undertook a series of tests on shell models at a scale of 1/100e composed of resin reinforced by glass fibre. During the tests, the self weight was represented by a vertical load and the wind was simulated by an offset load. The effect on the meridian shape, the thickness and the modulus were studied. The modal deformations and the vibratory responses were also measured. Due to the excellent coherence of the results, EDF modified the design regulations for cooling tower shells with the subject of buckling. (author)
Reliability Analysis of Cooling Towers: Influence of Rebars Corrosion on Failure
International Nuclear Information System (INIS)
Natural-draught cooling towers are used in nuclear power plants as heat exchangers. These structures are submitted to environmental loads such as wind and thermal gradients that are stochastic in nature. A probabilistic framework has been developed by EDF (Electricite de France) for assessing the durability of such structures. In this paper, the corrosion of the rebars due to concrete carbonation and the corresponding weakening of the reinforced concrete sections is considered. Due to the presence of time in the definition of the limit state function associated with the loss of serviceability of the cooling tower, time-variant reliability analysis has to be used. A novel approach is proposed to take into account the random 'initiation time', which corresponds to the time necessary for the carbonation to attain the rebars. Results are given in terms of the probability of failure of the structure over its life time. (authors)
Three-dimensional calculations of plumes in the near field of a cooling tower
International Nuclear Information System (INIS)
This paper shows a comparison between 3D computation and some results of scale models experiments in the near field of a cooling tower. We compare the velocity and temperature fields and we found a rather good agreement with the measurements. The rough description of the shell in the computation gives rise to a pressure field which has not the same intensity as the measured field
Experiences with the first dry cooling tower for the THTR power plant at Schmehausen, FRG
International Nuclear Information System (INIS)
The cable net cooling tower at Schmehausen was completed 12 years ago. Annual inspections are required by law. This paper reports on the following topics brought to light by these inspections: repair of damaged concrete on the pylon head; the search for a durable means of protecting the steel cables between the lifter ring and the thrust ring from corrosion; renewal of the attachment of the aluminium lining; cracks in the ring foundation; and weakening of the foundation anchors. (author)
The ring-stiffened shell of the ISAR II nuclear power plant natural-draught cooling tower
International Nuclear Information System (INIS)
The natural-draught cooling tower of the ISAR II nuclear power plant is one of the largest in the world. The bid specifications provided for an unstiffened cooling tower shell. For the execution, however, it was decided to adopt a shell with three additional stiffening rings. The present contribution deals with the static and dynamic calculations of the execution and, in particular, with the working technique employed for the construction of the rings. (author)
Prediction of ground vibration due to the collapse of a 235 m high cooling tower under accidental loads
International Nuclear Information System (INIS)
Highlights: ? Ground vibration due to the collapse of a huge cooling tower was predicted. ? Accidental loads with different characteristics caused different collapse modes. ? Effect of ground vibration on the nuclear-related facilities cannot be ignored. -- Abstract: A comprehensive approach is presented in this study for the prediction of the ground vibration due to the collapse of a 235 m high cooling tower, which can be caused by various accidental loads, e.g., explosion or strong wind. The predicted ground motion is to be used in the safety evaluation of nuclear-related facilities adjacent to the cooling tower, as well as the plant planning of a nuclear power station to be constructed in China. Firstly, falling weight tests were conducted at a construction site using the dynamic compaction method. The ground vibrations were measured in the form of acceleration time history. A finite element method based �falling weight-soil� model was then developed and verified by field test results. Meanwhile, the simulated collapse processes of the cooling tower under two accidental loads were completed in a parallel study, the results of which are briefly introduced in this paper. Furthermore, based on the �falling weight-soil� model, �cooling tower-soil� models were developed for the prediction of the ground vibrations induced by two collapse modes of the cooling tower. Finally, for a deep understanding of the vibration characteristics, a parametric study was also conducted with consideration of different collapse profiles, soil geologies as well as the arrangements of an isolation trench. It was found that severe ground vibration occurred in the vicinity of the cooling tower when the collapse happened. However, the vibration attenuated rapidly with the increase in distance from the cooling tower. Moreover, the �collapse in integrity� mode and the rock foundation contributed to exciting intense ground vibration. By appropriately arranging an isolation trench, the ground vibration can be significantly reduced
Improvements achieved in the cooling tower performance at the Leibstadt Nuclear Power Plant
International Nuclear Information System (INIS)
Appreciable improvements in the overall efficiency of various power plants can be obtained by modifications at the cold end of the thermal cycle. This paper summarizes new methods of analysis of this part of the plant and how these have successfully been used at the Leibstadt Nuclear Power Plant. The relatively low cost of performing these modifications has led to an investment pay back time of only 2 months. The problem of non optimum design of the cooling systems, cooling towers, condenser evacuation systems etc. seems to be caused generically by the lack of adequate engineering tools at the time the plants were built
The development of natural-draught cooling towers of prestressed wire-rope network construction of aerodynamic design
International Nuclear Information System (INIS)
Natural-draught cooling towers carried to a height of up to 200 m will be required for the dissipation of the residual heat from the thermal processes of large-capacity power stations to be erected in future. The structural problems involved in such large-size towers can be overcome by using prestressed wire-rope network construction. A structural concept is discussed which proposes to use a cooling tower shell constructed of a prestressed, planked wire-rope network of circular hyperbolic form carried by a spacer ring attached to the central mast. Comments are given on the ensuing problems of aerodynamics, stress-strength assessment, and erection. (orig.)
18 CFR 420.44 - Cooling water.
... 2010-04-01 2010-04-01 false Cooling water. 420.44 Section 420.44 Conservation...CHARGES Charges; Exemptions � 420.44 Cooling water. Water used exclusively for cooling purposes which is returned to the...
Performance of indices in cooling water system - a case study
International Nuclear Information System (INIS)
The corrosion/scale forming tendency of cooling water systems is generally predicted by measuring different saturation indices. For this purpose, indices like Langelier Saturation Index (LSI), Ryznar Stability Index (RSI) and Puckorius Scale Index (PSI) are generally used though many other indices have also been formulated for the same purpose. The main objective of using these indices is to adjust the cooling water chemistry to a non-corrosive condition. The Fast Breeder Test Reactor (FBTR) at Kalpakkam, Tamilnadu, India is a 40 MWt sodium cooled, mixed carbide (uranium and plutonium) fuelled nuclear test reactor. Cooling water system of FBTR comprises of service water system and condenser cooling water systems. Service water system forms the terminal heat sink for various process heat exchangers and steam water system auxiliary coolers. The condenser cooling water (CCW) system caters to main condenser, dump condenser, turbine oil cooler, generator air cooler and condensate cooler. Both the systems share a common induced draft-cooling tower, cooling water pit, corrosion monitoring set up, chlorinator and side stream filtration unit. In FBTR, cooling water system chemistry is maintained by dosing proprietary formulations comprising corrosion inhibitor, inorganic dispersant, bio-dispersant, chlorine activator and biocides along with chlorination. Water indices like LSI, RSI and PSI are being monitored for over a decade. These indices were formulated earlier to predict ndices were formulated earlier to predict the corrosion/scaling tendency in the municipal drinking water systems which were not subjected to any kind of chemical treatment. In this paper, the usefulness and applicability of these indices for predicting the corrosion/scale forming tendency of chemically treated cooling water is discussed based on the obtained corrosion and scale data for the period from May 1998 to Dec 2007. (author)
Improvement to Air2Air Technology to Reduce Fresh-Water Evaporative Cooling Loss at Coal-Based Thermoelectric Power Plants
Energy Technology Data Exchange (ETDEWEB)
Ken Mortensen
This program was undertaken to enhance the manufacturability, constructability, and cost of the Air2Air{TM} Water Conservation and Plume Abatement Cooling Tower, giving a validated cost basis and capability. Air2Air{TM} water conservation technology recovers a portion of the traditional cooling tower evaporate. The Condensing Module provides an air-to-air heat exchanger above the wet fill media, extracting the heat from the hot saturated moist air leaving in the cooling tower and condensing water. The rate of evaporate water recovery is typically 10% - 25% annually, depending on the cooling tower location (climate). This program improved the efficiency and cost of the Air2Air{TM} Water Conservation Cooling Tower capability, and led to the first commercial sale of the product, as described.
An experimental investigation on air-side performances of finned tube heat exchangers for indirect air-cooling tower
Directory of Open Access Journals (Sweden)
Du Xueping
Full Text Available A tremendous quantity of water can be saved if the air cooling system is used, comparing with the ordinary water-cooling technology. In this study, two kinds of finned tube heat exchangers in an indirect air-cooling tower are experimentally studied, which are a plain finned oval-tube heat exchanger and a wavy-finned flat-tube heat exchanger in a cross flow of air. Four different air inlet angles (90�, 60 �, 45�, and 30� are tested separately to obtain the heat transfer and resistance performance. Then the air-side experimental correlations of the Nusselt number and friction factor are acquired. The comprehensive heat transfer performances for two finned tube heat exchangers under four air inlet angles are compared. For the plain finned oval-tube heat exchanger, the vertical angle (90� has the worst performance while 45� and 30� has the best performance at small ReDc and at large ReDc, respectively. For the wavy-finned flat-tube heat exchanger, the worst performance occurred at 60�, while the best performance occurred at 45� and 90� at small ReDc and at large ReDc, respectively. From the comparative results, it can be found that the air inlet angle has completely different effects on the comprehensive heat transfer performance for the heat exchangers with different structures.
Prueitt, Melvin L. (Los Alamos, NM)
Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.
Synthesis of some novel sulfonamide derivatives and investigating their biocidal activity in cooling towers
Energy Technology Data Exchange (ETDEWEB)
Badawi, Abdelfattah M.; Mohamed, Dalia Emam; Hafiz, Amal A.; Amed, Sahar M. [Egyptian Petroleum Research Institute (EPRI), Nasr City, Cairo (Egypt). Applied Surfactants Lab.; Gohar, Yousry M. [Alexandria Univ. (Egypt). Microbiology Div.; Soliman, El-Sayed Ahmed [Ain Shams Univ., Cairo (Egypt). Chemistry Dept.; Sanan, Mohamed S. [Alexandria National Refining and Petrochemical Co. (ANRPC), Alexandria (Egypt)
A novel series of dibenzothiophenedioxide sulphonamide derivatives were synthesized and tested as antimicrobial agents. The chemical structures of the prepared compounds were confirmed by micro elemental analysis, fourier transform infrared (FT-IR) and proton nuclear magnetic resonance spectroscopy (H-NMR). The surface parameters of two of the prepared compounds were determined at 35 C including, surface tension, effectiveness, maximum surface excess and minimum surface area. Also the standard free energy of micellization and adsorption were recorded. The results showed that the prepared sulphonamides have good surface properties and effective antimicrobial activity against thirty three test organisms isolated from cooling towers. (orig.)
Reinforced concrete corrosion: Application of Bayesian networks to the risk management of a cooling tower
International Nuclear Information System (INIS)
Degradation modelling of concrete structures uses uncertain variables and leads, using reliability assessment, to time dependant evolution of failure probabilities. However, only few data are generally available to feed models leading to two types of uncertainties: an intrinsic one depending on the modelled phenomena and one related to the precision of the measurement. Each new data available is a piece of information which allows to update the initial prediction. In this article, an example of updating process, based on a Bayesian network, is presented and applied on the corrosion risk of a cooling tower. (authors)
Optimization of low-potential complex of NPP with mixed closed-cycle water cooling system
International Nuclear Information System (INIS)
The results of optimal design calculation of a circulation water cooling system in an NPP, whose power is stepped up from 2000 to 4000 MW are presented. It is assumed that the NPP comprises power plant units with a WWER-1000 reactor and saturated 6.5 MPa steam turbine of 1000 MW capacity. For two climatic zones of the European part of the USSR - the Center and the South - the possibility of raising the thermal load of the existing reservoir-cooler (R-C) system or using instead a combination of R-C plus cooling tower system is considered. It is shown that when the combination of R-C and cooling towers is used the low-potential complex parameters correspond to those of the most expensive part of the combined cooling system - the cooling towers
Cooling tower performance improvements for a cycling PC-fired unit
International Nuclear Information System (INIS)
The inevitable deregulation of the electric utility industry has caused many electric utility companies to look closely at their existing assets and predict what role these units will play in the future. Reducing a unit's production cost is the best way to prepare for the deregulated market but this benefit often comes with an associated capital expenditure. Spending capital dollars today can pose a quandary for an investor-owned utility committed to maintaining low consumer rates. The dilemma is: How does a utility improve its competitiveness position today while ensuring that the shareholders are getting a fair return on their investment when any fuel savings are passed through to the consumer? Illinois Power (IP) has been aggressively looking to improve their current competitive position while facing the current regulatory challenges. Studies have been commissioned to identify the most attractive cost reduction opportunities available. One study identified that improving the performance of the Unit 6 cooling tower at the Havana Station would be a very economically attractive option. This paper addresses the economics of refurbishing a cooling tower for a cycling pulverized-coal (PC) unit to provide a competitive advantage leading into the deregulated electricity market
Factors influencing the effectiveness of ion exchange resins used for chromate removal [from cooling tower effluents
International Nuclear Information System (INIS)
Factors influencing the effectiveness of ion exchange resins used for chromate removal [from cooling tower effluents] containing chromate-based corrosion inhibitors, such as the CL-68 solution (17% zinc, 15% chromate), were studied in batch equilibrium experiments at ambient temperature. The adsorptive capacity (AC) of Amberlite IRA-900 resin markedly deteriorated with decreasing pH (3.3 to 6.1) from a maximum at pH.5. Experiments on chromate adsorption in the presence of typical cooling tower blowdown impurities showed a reduction in the AC of the resin at > 3000 ppM sodium chloride, but no adverse effect of sodium 2,4,5-trichlorophenate (70 to 314 ppM) or burner fuel oil (37 to 166 ppM) at pH.5 and 183 to 265 ppM input chromate concentration. Packed column studies supported the batch test results on the effect of pH and fuel oil (17,500 ppM) and showed no deterioration in the resin AC from the Triton X surfactant solution which was used to clean resin fouled by the fuel oil
Lawrence Livermore National Laboratory (LLNL) Experimental Test Site (Site 300) Salinity Evaluation and Minimization Plan for Cooling Towers and Mechanical Equipment Discharges
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Daily III, W D
This document was created to comply with the Central Valley Regional Water Quality Control Board (CVRWQCB) Waste Discharge Requirement (Order No. 98-148). This order established new requirements to assess the effect of and effort required to reduce salts in process water discharged to the subsurface. This includes the review of technical, operational, and management options available to reduce total dissolved solids (TDS) concentrations in cooling tower and mechanical equipment water discharges at Lawrence Livermore National Laboratory's (LLNL's) Experimental Test Site (Site 300) facility. It was observed that for the six cooling towers currently in operation, the total volume of groundwater used as make up water is about 27 gallons per minute and the discharge to the subsurface via percolation pits is 13 gallons per minute. The extracted groundwater has a TDS concentration of 700 mg/L. The cooling tower discharge concentrations range from 700 to 1,400 mg/L. There is also a small volume of mechanical equipment effluent being discharged to percolation pits, with a TDS range from 400 to 3,300 mg/L. The cooling towers and mechanical equipment are maintained and operated in a satisfactory manner. No major leaks were identified. Currently, there are no re-use options being employed. Several approaches known to reduce the blow down flow rate and/or TDS concentration being discharged to the percolation pits and septic systems were reviewed for technical feasibility and cost efficiency. These options range from efforts as simple as eliminating leaks to implementing advanced and innovative treatment methods. The various options considered, and their anticipated effect on water consumption, discharge volumes, and reduced concentrations are listed and compared in this report. Based on the assessment, it was recommended that there is enough variability in equipment usage, chemistry, flow rate, and discharge configurations that each discharge location at Site 300 should be considered separately when deciding on an approach for reducing the salt discharge to the subsurface. The smaller units may justify moderate changes to equipment, and may benefit from increased cleaning frequencies, more accurate and suitable chemical treatment, and sources of make up water and discharge re-use. The larger cooling towers would be more suitable for automated systems where they don't already exist, re-circulation and treatment of blow down water, and enhanced chemical dosing strategies. It may be more technically feasible and cost efficient for the smaller cooling towers to be replaced by closed loop dry coolers or hybrid towers. There are several potential steps that could be taken at each location to reduce the TDS concentration and/or water use. These include: sump water filtration, minimization of drift, accurate chemical dosing, and use of scale and corrosion coupons for chemical calibration. The implementation of some of these options could be achieved by a step-wise approach taken at two representative facilities. Once viable prototype systems have been proven in the field, systematic implementation should proceed for the remaining systems, with cost, desired reduction, and general feasibility taken into consideration for such systems.
Development of an Accident Management Program for the K-Reactor cooling tower at the Savannah River Site
International Nuclear Information System (INIS)
This report discusses the Accident Management program at SRS has developed a new methodology for the safe operation of the K-Reactor. This methodology was recently applied during the loss of ultimate heat sink analysis which answers the question of which alternatives are present when the Reactor loses it primary cooling source. With the addition of a new cooling tower there is a need to reapply and perhaps modify the analysis to include the effects of the tower on the existing systems. This process combines the efforts of many different groups. Included in these efforts are interviews with operators, information from documents and drawings, data from computer codes, practice from in-plant drills, and efforts from multi-functional organizations. The central theme of this paper is the explanation of the task involved in the methodology and its application to the cooling tower addition
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Purpose: To flatten the power distribution for the entire reactor by suppressing the power near the center in the direction of the reactor core height, increasing the linear power near the upper end in the direction of the reactor core height and increasing the linear power also near the lower end in the direction of the reactor core height. Constitution: The fuel rods comprise three type of rods, i.e., long fuel rods each having a length over the entire height of the reactor core, short fuel rods forming light water passages at the lower end of the reactor core and short fuel rods forming light water passages at the upper end of the reactor core. Then, the water to fuel volume ratio per unit cross sectional area is made smaller near the center in the direction of the reactor core height, while made greater near the upper and the lower ends in the direction of the reactor core height. (Yoshino, Y.)
Operational issues involving use of supplementary cooling towers to meet stream temperature standards with application to the Browns Ferry Nuclear Plant
International Nuclear Information System (INIS)
A mixed mode cooling system is one which operates in either the open, closed, or helper (once-through but with the use of the cooling towers) modes. Such systems may be particularly economical where the need for supplementary cooling to meet environmental constraints on induced water temperature changes is seasonal or dependent upon other transient factors such as stream-flow. The issues involved in the use of mixed mode systems include the design of the open cycle and closed cycle portions of the cooling system, the specification of the environmental standard to be met, and the monitoring system and associated decision rules used to determine when mode changes are necessary. These issues have been examined in the context of a case study of TVA's Browns Ferry Nuclear Plant which utilizes the large quantity of site specific data reflecting conditions both with and without plant operation
Sensitivity study of a method for updating a finite element model of a nuclear power station cooling tower
International Nuclear Information System (INIS)
The Research and Development Division of Electricite de France is developing a surveillance method of cooling towers involving on-site wind-induced measurements. The method is supposed to detect structural damage in the tower. The damage is identified by tuning a finite element model of the tower on experimental mode shapes and eigenfrequencies. The sensitivity of the method was evaluated through numerical tests. First, the dynamic response of a damaged tower was simulated by varying the stiffness of some area of the model shell (from 1 % to 24 % of the total shell area). Second, the structural parameters of the undamaged cooling tower model were updated in order to make the output of the undamaged model as close as possible to the synthetic experimental data. The updating method, based on the minimization of the differences between experimental modal energies and modal energies calculated by the model, did not detect a stiffness change over less than 3 % of the shell area. Such a sensitivity is thought to be insufficient to detect tower cracks which behave like highly localized defaults. (author). 8 refs., 9 figs., 6 tabs
Dry cooling towers for GT-MHR - HTR2008-58182
International Nuclear Information System (INIS)
Due to problems with the availability and the price of water, and the concerns relating to adverse environmental effects of wet cooling systems, the need for water conserving cooling systems has been increasing. Presently, dry cooling accounts for over 30, 000 MWe of capacity in more than 30 countries. GT-MHR is specially suited for use of dry cooling due to 1) high efficiency, 2) high heat rejection temperatures and 3) large temperature difference between the turbine inlet and heat rejection temperatures. Higher efficiency means the amount of energy rejected to the cooling per MWe is less. The majority of heat is rejected in pre-cooler and inter-cooler at helium temperature of more than 100 deg. C. This results in higher temperature difference for heat rejection. Also due to large temperature difference between the turbine inlet and heat rejection temperatures, changes in ambient temperature have a smaller effect on overall thermal efficiency. Preliminary evaluation shows that pure dry cooling is economical for GT-MHR for water cost of more than 0.8$/m3 and power cost of 3.5 c/kWh. A combination of dry and wet cooling can reduce large percentage of the water use without affecting the efficiency. (authors)
Cost and performance optimization of natural draft dry cooling towers using genetic algorithm. Paper no. IGEC-1-002
International Nuclear Information System (INIS)
In this paper the cost - performance optimization of natural draft dry cooling towers with specific kind of heat exchangers, known as Forgo T60 has been investigated. These cooling towers are used in combined and steam cycle power plants. The optimization has been done using genetic algorithm. The objective function has two parts, which are minimizing the cost and maximizing the performance. In the first part the geometrical and operating parameters are defined and for the next part the performance of the designed tower for different ambient temperatures during a year is calculated considering the characteristic curve of the turbine. The applied genetic algorithm has been tuned up using the data of some working power cycles. The results show it is possible to find an optimum for all design parameters; however it is very dependent on how exact the cost analysis is. (author)
Effect of cooling tower vapours on agriculture in the environment of power plants
International Nuclear Information System (INIS)
The effect of cooling tower vapours according to investigations made so far are mainly noticeable regarding solar radiation, and this is practically merely in the immediate neighbourhood of the power plant. The effective influence on photosynthesis should be hardly detectable even in this limited area around the power plant. The effect on the temperature is minimum, the influence on the relative moisture is so small that it lies within the margin of error of measuring, with the exception of the few cases in which the vapours are pressed down to the ground. One need not reckon with an increased fungoid growth and bad drying conditions. Rainfall could be additionally increased if the weather situation is likely to rain or if it is raining anyway. Regarding fog frequency, one may assume that there might be a certain increase in fog. So far no cases are known in which fog would occur where there is no general tendency for fog formation. (orig.)
Multi-objective optimization of a cooling tower assisted vapor compression refrigeration system
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Sayyaadi, Hoseyn; Nejatolahi, Mostafa [Faculty of Mechanical Engineering-Energy Division, K.N. Toosi University of Technology, P.O. Box 19395-1999, No. 15-19, Pardis Str., Mollasadra Ave., Vanak Sq., Tehran 1999 143344 (Iran, Islamic Republic of)
A cooling tower assisted vapor compression refrigeration machine has been considered for optimization with multiple criteria. Two objective functions including the total exergy destruction of the system (as a thermodynamic criterion) and the total product cost of the system (as an economic criterion), have been considered simultaneously. A thermodynamic model based on energy and exergy analyses and an economic model according to the Total Revenue Requirement (TRR) method have been developed. Three optimized systems including a single-objective thermodynamic optimized, a single-objective economic optimized and a multi-objective optimized are obtained. In the case of multi-objective optimization, an example of decision-making process for selection of the final solution from the Pareto frontier has been presented. The exergetic and economic results obtained for three optimized systems have been compared and discussed. The results have shown that the multi-objective design more acceptably satisfies generalized engineering criteria than other two single-objective optimized designs. (author)
Buckling and failure analysis of cooling tower and its application to a real case
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The paper presents a computational model for reinforced concrete multilayered shell element taking into account geometrical and physical non-linearities. The shell element results from the superposition of a plate element based on the discretization of the Mindlin theory, and the CST element. The initial curvature is incorporated using the Marguerre shallow shell theory. The constitutive model for the uncracked concrete is based on the elastoplastic theory and for the cracked concrete a tension softening behaviour is assumed. The description of the motion is made in the corotational Lagrangian formulation. The numerical part of the paper contains a detailed study of a built cooling tower. It is shown that the buckling load resulting from linear prebuckling analysis is considerably larger than the ultimate load. (author)
Heat and mass transfer in cooling towers - comparison of 1D numerical simulation with the technical approach.
Czech Academy of Sciences Publication Activity Database
Zuniga-Gonzalez, Israel; Mar��k, Franti�ek
Vol. 2. Tokyo : Hosei University, 2005 - (Mizuki, S.; Setoguchi, T.), s. 505-510 [ISAIF /7./ : International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows /7./. Tokyo (JP), 11.09.2005-15.09.2005] R&D Projects: GA ?R(CZ) GA101/05/2536; GA M�k 1P05ME726 Institutional research plan: CEZ:AV0Z20760514 Keywords : cooling tower * evaporative cooling * heat transfer Subject RIV: BK - Fluid Dynamics
Water quality control and analysis of the secondary cooling system in HANARO
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The secondary cooling system in HANARO includes the chemical injection system. The cooling system has a basin, a cooling tower with four cooling fans, three cooling pumps of 50% capacity, related valves, pipings and instruments. The chemical injection system has two tanks containing different kinds of chemicals, four injection pumps, related valves and pipings. The cooling method is mechanical induced drift type. While the cooling water is circulating, the heat is transmitted to the cooling water in the exchangers and emitted into the often air by forced draft in the cooling tower. Due to the loss of cooling water by evaporation, various kinds of undesirable substances such as salts in solution and micro organisms are accumulated in the cooling water, and they could result in defects such as corrosion, scale, and slime in the system. Therefore, the causes of degradation such as corrosion, scale, and slime are restrained by injection of the chemicals into the cooling water, and the concentration of chemicals is controlled by the periodic blowdown of the cooling water. While the blowdown is nothing but discharging the water out of the system for the control of the cooling water quality, it causes increasing the amount of waste of service water on the contrary. To avoid such counter effect of the blowdown function, the system to operate without blowdown was considered and investigated. Should the system be realized about 100 tons of service water is expected to be saved every working day. In this report, the basic theory is described about the water quality control for the secondary cooling water. The validity and the amount of chemicals being used were reviewed to maintain the water quality. The overall situation of water quality control were analysed as well by reviewing of the quality of cooling water between 1997 and 1999. Furthermore the relation between the number of cycles and the rate of loss of cooling water was confirmed to demonstrate that the secondary cooling water can be managed by high Ca-hardness treatment without blowdown to minimize the loss of cooling water
Design of, and results of investigations into, indirect cooling for 1200 MW pressurised water reactor power stations
International Nuclear Information System (INIS)
Indirect dry cooling for extreme air temperature variations from -160C to +420C has been investigated for a site in an earthquake zone which is short of water. In addition, high wind velocities and storms occur at this site. The investigation was based on four similar dry cooling towers operating in parallel,in order to keep broadly within the range of proven ratings for dry cooling towers using this type of cooling system. The results of the optimised design data and of wind tunnel and laboratory investigations are described in detail together with literature studies under prescribed conditions. (orig.)
Cooling water for SSC experiments: Supplemental Conceptual Design Report (SCDR)
International Nuclear Information System (INIS)
This paper discusses the following topics on cooling water design on the superconducting super collider; low conductivity water; industrial cooling water; chilled water systems; and radioactive water systems
Effect of supporting structure stiffness on the drive train assembly of an induced draft cooling tower under seismic effects
International Nuclear Information System (INIS)
In a nuclear power project an induced draft cooling tower, as a safety-related structure and part of the main cooling system, has to perform satisfactorily under designated seismic effects. While the structural elements can be designed by conventional methods to ensure adequate safety, the seismic qualification of the mechanical components poses a challenge. The paper describes a methodology adopted for the seismic qualification of a typical Drive Train Assembly for the axial flow fan of an induced draft cooling tower, to ensure the structural integrity and functional operability of the assembly during Operating Base Earthquake and Safe Shutdown Earthquake conditions. This is achieved by performing a detailed finite element analysis of the rotating equipment assembly consisting of the electric motor, gear box and fan along with the drive shaft between the motor and the gear box. The various components are modeled using beam elements, plate elements and spring elements to idealize the flexible connections and supports. The floor response spectra derived from a dynamic analysis of the overall structure under stipulated seismic acceleration spectra are the main excitation inputs into the system. The results validate the adequacy of gaps for movement and the strengths of the couplings and bolts to withstand the applied loads. The assumed modeling and analysis methodology are seen to be acceptable procedures for seismic qualification of important components of the cooling on of important components of the cooling tower. (authors)
Measuring environmental pollution and the effect of cooling towers in the 220 kV substation of the V-1 nuclear power plant at Jaslovske Bohunice
International Nuclear Information System (INIS)
Two methods are described used to study the level of environmental pollution and the effect of cooling towers on the insulation of the 220 kV substation of the nuclear power plant. The use of the IMICONT apparatus is based on a change in the conductivity of an absorption solution following the passage of air. The change in conductivity is proportional to air pollution. The EGU method is based on measuring the conductivity of fallout trapped in a constant amount of water. The results of measurement show good agreement for the two measuring methods. (J.C.)
Hydraulic design of a low-specific speed Francis runner for a hydraulic cooling tower
International Nuclear Information System (INIS)
The air blower in a cooling tower is normally driven by an electromotor, and the electric energy consumed by the electromotor is tremendous. The remaining energy at the outlet of the cooling cycle is considerable. This energy can be utilized to drive a hydraulic turbine and consequently to rotate the air blower. The purpose of this project is to recycle energy, lower energy consumption and reduce pollutant discharge. Firstly, a two-order polynomial is proposed to describe the blade setting angle distribution law along the meridional streamline in the streamline equation. The runner is designed by the point-to-point integration method with a specific blade setting angle distribution. Three different ultra-low-specificspeed Francis runners with different wrap angles are obtained in this method. Secondly, based on CFD numerical simulations, the effects of blade setting angle distribution on pressure coefficient distribution and relative efficiency have been analyzed. Finally, blade angles of inlet and outlet and control coefficients of blade setting angle distribution law are optimal variables, efficiency and minimum pressure are objective functions, adopting NSGA-II algorithm, a multi-objective optimization for ultra-low-specific speed Francis runner is carried out. The obtained results show that the optimal runner has higher efficiency and better cavitation performance.
NASA Marshall Space Flight Center Improves Cooling System Performance: Best Management Practice Case Study #10: Cooling Towers (Fact Sheet)
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National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) has a longstanding sustainability program that revolves around energy and water efficiency as well as environmental protection. MSFC identified a problematic cooling loop with six separate compressor heat exchangers and a history of poor efficiency. The facility engineering team at MSFC partnered with Flozone Services, Incorporated to implement a comprehensive water treatment platform to improve the overall efficiency of the system.
Pulsed cooling-water systems for actively cooled beam dumps
International Nuclear Information System (INIS)
A pulsed water system offers an economically attractive way of supply cooling water for beam dumps, as the water flow and pressure requirements increase. A pilot system was built and used in testing prototype beam dumps. Operating experience gained with the pulsed water system has proved the feasibility of this design
An experimental study on natural draft-dry cooling tower as part of the passive system for the residual decay heat removal
International Nuclear Information System (INIS)
An experimental apparatus has been built in order to perform sensitivity analysis on the performance of a natural draft-dry cooling tower. This component plays an important role in the passive system for the residual heat decay removal foreseen in the MARS reactor and in the GCFR of the Generation IV reactors. The sensitivity analysis has investigated: 1) the heat exchanger arrangement; two different arrangements have been considered: a horizontal arrangement, in which a system of electrical heaters are placed at the inlet cross section of the tower, and a vertical arrangement, with the heaters distributed vertically around the circumference of the tower. 2) The shape of the cooling tower; by varying the angle of the shell inclination it is possible to obtain a different shape for the tower itself. An upper and a lower angle inclination were modified and by a calculation procedure eleven different configuration were selected. 3) The effect of cross wind on the tower performance. An equation-based procedure to design the dry-cooling tower is presented. In order to evaluate the influence of the shape and the heat exchanger arrangement on the performance of the cooling tower, a geometrical factor (FG) and a thermal factor (FT) are introduced. By analyzing the experimental results, engineering design relations are obtained to model the cooling tower performance. The comparison between the experimental heat transfer coefficient and the heat transfer coefficient obtained by the heat transfer coefficient obtained by the mathematical procedure shows that there is a good agreement. The obtained results show that it is possible to evaluate the shape and the heat exchanger arrangement to optimize the performance of the cooling tower either in wind-less condition either in presence of cross wind. (authors)
A multi-layered model for collapse analysis of large reinforced concrete natural-draft cooling towers
International Nuclear Information System (INIS)
The modelling of the material behavior of the reinforced concrete is managed by utilizing Bazant's plastic-fracturing theory for the concrete and an elasto-plastic material law, including the Bauschinger effect, for the rebar. The theoretical basis of the model is the shear deformation theory as well as the Kirchhoff-Love theory in the sense of Donnell-Marguerre's approach. To consider the discontinuity of strains in the case of the cracked concrete, mixed FE-models that are based on Hellinger-Reissner's variational principle and its modified version are developed. At last, the damage evolution of a large natural draught cooling tower until collapse is traced numerically. The collapse analysis was performed under dead load and quasi-static wind action. The collapse simulation demonstrates the weakening of the cooling tower under the load combinations according to Euro-code and BTR taking the variability of the material properties into account. (orig./HP)
Johnson screen for cooling water intakes
International Nuclear Information System (INIS)
Johnson surface-water screens provide an alternative to vertical traveling screens for power plant cooling water intakes. In this paper, flow field modeling is discussed, and a series of case studies is presented. The hydraulic information obtained is discussed as it applies to the exclusion of biota and debris from cooling water intake systems
Efficient Water Management in Water Cooled Reactors
International Nuclear Information System (INIS)
One of the IAEA's statutory objectives is to 'seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world'. One way this objective is achieved is through the publication of a range of technical series. Two of these are the IAEA Nuclear Energy Series and the IAEA Safety Standards Series. According to Article III.A.6 of the IAEA Statute, the safety standards establish 'standards of safety for protection of health and minimization of danger to life and property.' The safety standards include the Safety Fundamentals, Safety Requirements and Safety Guides. These standards are written primarily in a regulatory style, and are binding on the IAEA for its own programmes. The principal users are the regulatory bodies in Member States and other national authorities. The IAEA Nuclear Energy Series comprises reports designed to encourage and assist R and D on, and application of, nuclear energy for peaceful uses. This includes practical examples to be used by owners and operators of utilities in Member States, implementing organizations, academia, and government officials, among others. This information is presented in guides, reports on technology status and advances, and best practices for peaceful uses of nuclear energy based on inputs from international experts. The IAEA Nuclear Energy Series complements the IAEA Safety Standards Series. Water scarcity is becoming one of the most pressing crises affecting the planet. A t pressing crises affecting the planet. A reliable supply of water and energy is an important prerequisite for sustainable development. A large number of nuclear power reactors are being planned in many developing countries to address these countries' increasing energy demands and their limited fossil resources. New construction is expected in the USA, Europe and Asia, as well. Reducing water use and consumption by nuclear power plants is likely to help developing countries in introducing nuclear power into their energy supply mix. A large number of the countries that have recently begun to consider the introduction of nuclear power are in water scarce regions, which would certainly limit the possibility for deployment of nuclear power plants, in turn hindering these countries' development and energy security. Thus, there is a large incentive to enhance efforts to introduce innovative water use, water management practices and related technologies. Water management for nuclear power plants is gaining interest in IAEA Member States as an issue of vital importance for the deployment of nuclear power. Recent experience has shown that some nuclear power plants are susceptible to prolonged drought conditions, forcing reactors to be shut down or power to be reduced to a minimal level. In some cases, environmental issues have resulted in regulations that limit the possibility for water withdrawal as well as water discharge. Regarding the most common design for cooling nuclear power plants, this has led to a complicated siting procedure for new plants and expensive retrofits for existing ones. The IAEA has already provided its Member States with reports and documents that address the issue. At the height of nuclear power expansion in the 1970s, the need for guidance in the area resulted in publications such as Thermal Discharges at Nuclear Power Stations - Their Management and Environmental Impact (Technical Reports Series No. 155) and Environmental Effects of Cooling Systems (Technical Reports Series No. 202). Today, amid the so-called nuclear renaissance, it is of vital importance to offer guidance to the Member States on the issues and possibilities that nuclear power water management brings. Management of water at nuclear power plants is an important subject during all phases of the construction, operation and maintenance of any nuclear power plant. Water management addresses the issue of securing water for condenser cooling during operation, for construction (during the flushing phase), and for inventory control, including make-up to the primary coolant system a
Stresses on a water intake at sea comprising three emerging towers
International Nuclear Information System (INIS)
The study relating to the water intake, of a nuclear power station in the Tyrrhenian Sea, comprising a platform and three towers has been carried out on a scale model with random breaking waves. The Pierson-Moskowitz and Jonswap spectrums have been reproduced and the overall stresses and pressures on the structure, as well as the linking stresses between the towers and the platform, have been measured. The measurement equipment comprised capacitive sensors, a six component scale and darts for the embedding of towers in the platform, with digitalized acquisition and computerized processing. The study has made it possible to assess the overall stability of the works and the safety factor
Explosive Demolition of a Fire-Water Tower At East Tennessee Technology Park, Oak Ridge TN
International Nuclear Information System (INIS)
On June 17, 2006, the Department of Energy (DOE) successfully demolished a ?60 year old fire-water tower (K-1206-E), located at the East Tennessee Technology Park (ETTP) in Oak Ridge, TN, using strategically placed explosive charges. The subject demolition project was executed by MCM Management Corporation and Demolition Dynamics under the management of DoE's prime contractor Bechtel Jacobs Company LLC (BJC). The K-1206-E Fire Water Tower (Tower) supported the ETTP fire water protection system from the mid- 1950's until 1991. The 378,500-L (100,000-gallon) Tower, elevated 53-m (175-feet) above grade, was located in a grassy area within 152-m (500-feet) of several other occupied facilities. Electrical, control circuits and supply water servicing the Tower were deactivated in 2003. Free liquids and sludge were removed from the tank prior to demolition. Demolition of a facility employing explosive demolition at a federal site in the 'post-9/11 era' was a substantial challenge. The subject paper discusses: - the planning and coordination steps that were taken to successfully overcome the challenges prior to the demolition of the empty, deactivated Tower; - the method used for the engineered demolition of the Tower; and - the factors responsible for the successful execution of this demolition project. At least two previous attempts were made to demolish the Tower. In the first attempt, the execution of the project was deferred by the re-allocation of funds. In the subseqhe re-allocation of funds. In the subsequent attempt in 2004, the execution of this project was postponed due to concerns that an adjacent facility would have to shut down operations during the duration of mobilization and execution of the project and thereby incur potential financial losses. A total of 51 cubic meters (1,800 cubic feet) of demolition debris was generated, which was compliantly disposed of at a local landfill followed by site restoration
Water Cooled FBNR Nuclear Reactor
International Nuclear Information System (INIS)
A new era of nuclear energy is emerging through innovative nuclear reactors that are to satisfy the new philosophies and criteria that are developed by the INPRO program of the International Atomic Energy Agency (IAEA). The IAEA is establishing a new paradigm in relation to nuclear energy. The future reactors should meet the new standards in respect to safety, economy, non-proliferation, nuclear waste, and environmental impact. The Fixed Bed Nuclear Reactor (FBNR) is a small (70 MWe) nuclear reactor that meets all the established requirements. It is an inherently safe and passively cooled reactor that is fool proof against nuclear proliferation. It is simple in design and economic. It can serve as a dual purpose plant to produce simultaneously both electricity and desalinated water thus making it especially suitable to the needs of most of developing countries. FBNR is developed with the support of the IAEA under its program of Small Reactors Without On-Site Refuelling (SRWOSR). The FBNR reactor uses the pressurized water reactor (PWR) technology. It fulfills the objectives of design simplicity, inherent and passive safety, economy, standardization, shop fabrication, easy transportability and high availability. The inherent safety characteristic of the reactor dispenses with the need for containment; however, a simple underground containment is envisaged for the reactor in order to reduce any adverse visual impact. (author)
Application of an Optimum Design of Cooling Water System by Regeneration Concept and Pinch Technology for Water and Energy Conservation
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A. Ataei
Full Text Available In this study, using a combination of Pinch Technology and Mathematical Programming, a new technique is presented in order to grass-root design for a cooling water system to achieve minimum total annual cost. The presented technique is further improved by using patterns from the concept of regeneration recycling in water systems; in a sense that cooling water is regenerated locally by an air cooler. Moreover, in the proposed method, optimum design of cooling tower has been achieved through a mathematical model. Related coding in MATLAB version 7.3 was used for the illustrative example to get optimal values in the proposed cooling water design method computations. The result of the recently introduced design methodology was compared with the conventional and Kim and Smith design methods. The outcomes indicate that by using this new design method, more water and energy can be saved and a lower level of total annual cost can be reached.
Injected Water Augments Cooling In Turboshaft Engine
Biesiadny, Thomas J.; Berger, Brett; Klann, Gary A.; Clark, David A.
Report describes experiments in which water injected into compressor-bleed cooling air of aircraft turboshaft engine. Injection of water previously suggested as way to provide additional cooling needed to sustain operation at power levels higher than usual. Involves turbine-inlet temperatures high enough to shorten lives of first-stage high-pressure turbine blades. Latent heat of vaporization of injected water serves as additional heat sink to maintain blades at design operating temperatures during high-power operation.
Sea-water intake tower works for Hamaoka Nuclear Power Station No. 2 Plant
International Nuclear Information System (INIS)
It was determined to adopt tunnel system based on the conclusion of negotiation with local people, specifically fishermen, for the sea water intake arrangement in Hamaoka Nuclear Power Station. The main factors for determining the location of the intake tower included marine conditions such as waves and littoral sand drift, and the sea-bottom topographic features and geology of tunnel route, for which field examination, hydraulic experiments and the research and investigation on the method of construction were carried out. These results in the No.2 tower installation at the point 65 m to the east of the No.1 tower. The construction of the tower is described on the manufacture and conveyance of steel caisson, land works at Omaezaki and temporary assembly works on the sea. Then the details of tower installation and the works on site are reported. Fortunately the difficult sea works have been satisfactorily completed earlier than planned, without any accident. The construction facilities utilizing a pilot tunnel seem to have made the better achievement than expected. In spite of the results, the lifting up, off-shore conveyance, and installation of the intake tower caisson, a superheavy structure of weighting up to total 2900 ton, were critical works. (Wakatsuki, Y.)
40 CFR 401.14 - Cooling water intake structures.
...2010-07-01 true Cooling water intake structures. 401.14 Section...PROVISIONS � 401.14 Cooling water intake structures. The location...construction and capacity of cooling water intake structures of any point...
Reinforced concrete corrosion: application of Bayesian networks to the risk management of cooling towers in nuclear plants
International Nuclear Information System (INIS)
Degradation modeling of concrete structures uses uncertain variables and leads, using reliability assessment, to time dependant evolution of failure probabilities. However, only few data are generally available to feed models leading to two types of uncertainties: an intrinsic one depending on the modeled phenomena and one related to the precision of the measurements. Each new data available is a piece of information which allows updating the initial prediction. In this article, an example of updating process, based on a Bayesian network, is presented and applied on the corrosion risk of a cooling tower in a nuclear plant. (authors)
Corrosion of reinforced concrete in nuclear plants: application of Bayesian networks to the risk management of cooling towers
International Nuclear Information System (INIS)
Degradation modelling of concrete structures uses uncertain variables and leads, using reliability assessment, to time dependant evolution of failure probabilities. However, only few data are generally available to feed models leading to two types of uncertainties: an intrinsic one depending on the modelled phenomena and one related to the precision of the measurements. Each new data available is a piece of information which allows updating the initial prediction. In this article, an example of updating process, based on a Bayesian network, is presented and applied on the corrosion risk of a cooling tower in a nuclear plant. (authors)
Thermal calculations for water cooled research reactors
International Nuclear Information System (INIS)
The formulae and the more important numerical data necessary for thermic calculations on the core of a research reactor, cooled with low pressure water, are presented. Most of the problems met by the designer and the operator are dealt with (calculations margins, cooling after shut-down). Particular cases are considered (gas release, rough walls, asymmetric cooling slabs etc.), which are not generally envisaged in works on general thermics
River and cooling water temperature fluctuations
International Nuclear Information System (INIS)
Cooling water discharged from a power plant changes the fluctuating water temperature characteristics of a receiving river in a clearly detectable way. Daily and hourly water temperature data from two power plant sites on the Upper Mississippi River were used to compute for illustration the magnitude of such differences. Extreme value analysis, autocovariance and spectral analysis, and nonlinear curve fitting methods were applied alternatively. Amplitudes of seasonal periodicities, of diurnal periodicities, and of random components were determined. The results indicate that time series analysis of water temperatures measured downstream from an existing cooling water outfall may provide equally or even more realistic and useful information on the size of a cooling water plume than quasi-instantaneous surveys of spatial water temperature distributions
Energy Technology Data Exchange (ETDEWEB)
IBM Corporation; Energy Efficient HPC Working Group; Hewlett Packard Corporation; SGI; Cray Inc.; Intel Corporation; U.S. Army Engineer Research Development Center; Coles, Henry; Ellsworth, Michael; Martinez, David J.; Bailey, Anna-Maria; Banisadr, Farhad; Bates, Natalie; Coghlan, Susan; Cowley, David E.; Dube, Nicholas; Fields, Parks; Greenberg, Steve; Iyengar, Madhusudan; Kulesza, Peter R.; Loncaric, Josip; McCann, Tim; Pautsch, Greg; Patterson, Michael K.; Rivera, Richard G.; Rottman, Greg K.; Sartor, Dale; Tschudi, William; Vinson, Wade; Wescott, Ralph
Liquid cooling is key to reducing energy consumption for this generation of supercomputers and remains on the roadmap for the foreseeable future. This is because the heat capacity of liquids is orders of magnitude larger than that of air and once heat has been transferred to a liquid, it can be removed from the datacenter efficiently. The transition from air to liquid cooling is an inflection point providing an opportunity to work collectively to set guidelines for facilitating the energy efficiency of liquid-cooled High Performance Computing (HPC) facilities and systems. The vision is to use non-compressor-based cooling, to facilitate heat re-use, and thereby build solutions that are more energy-efficient, less carbon intensive and more cost effective than their air-cooled predecessors. The Energy Efficient HPC Working Group is developing guidelines for warmer liquid-cooling temperatures in order to standardize facility and HPC equipment, and provide more opportunity for reuse of waste heat. This report describes the development of those guidelines.
Outbreak of legionnaires' disease from a cooling water system in a power station (Heysham)
International Nuclear Information System (INIS)
In September and October 1981 six cases of pneumonia occurred among men working in a power station under construction. Three were identified as cases of legionella pneumonia and two others had serology suggestive of legionella infection. In a sample of 92 men from the site 10 had low levels of antibodies to legionella; a similar sample of men working on an adjacent site showed none with positive serology. In a case control study it was found that cases of pneumonia were more likely than controls to have worked on a part of the site where four small capacity cooling towers were located. Legionella pneumophila serogroup 1 was isolated from the water systems of these four towers but was not found in samples from any other cooling towers or hot or cold water outlets on the site. It would appear that there was airborne spread of the organism from these cooling water systems which had not received conventional treatment to inhibit corrosion and organic growth. This is the first outbreak of legionnaires' disease to be recorded in an industrial setting in the United Kingdom. No cases of legionella infection have occurred on the site since the introduction of control measures. (author)
International Nuclear Information System (INIS)
This report has been prepared for the Department of Energy, Office of Nuclear Energy (DOE-NE), for the purpose of providing a status report on the challenges and opportunities facing the U.S. commercial nuclear energy industry in the area of plant cooling water supply. The report was prompted in part by recent Second Circuit and Supreme Court decisions regarding cooling water system designs at existing thermo-electric power generating facilities in the U.S. (primarily fossil and nuclear plants). At issue in the courts have been Environmental Protection Agency regulations that define what constitutes 'Best Technology Available' for intake structures that withdraw cooling water that is used to transfer and reject heat from the plant's steam turbine via cooling water systems, while minimizing environmental impacts on aquatic life in nearby water bodies used to supply that cooling water. The report was also prompted by a growing recognition that cooling water availability and societal use conflicts are emerging as strategic energy and environmental issues, and that research and development (R and D) solutions to emerging water shortage issues are needed. In particular, cooling water availability is an important consideration in siting decisions for new nuclear power plants, and is an under-acknowledged issue in evaluating the pros and cons of retrofitting cooling towers at existing nuclear plants. Because of the significant ongoing research on water issues already being pg research on water issues already being performed by industry, the national laboratories and other entities, this report relies heavily on ongoing work. In particular, this report has relied on collaboration with the Electric Power Research Institute (EPRI), including its recent work in the area of EPA regulations governing intake structures in thermoelectric cooling water systems.
Development of a new method of measurement of the polarization resistance to estimate the level of corrosion of the reinforced concrete of cooling towers
International Nuclear Information System (INIS)
This paper summarises the results obtained from the numerical simulations of an operative measurement mode of polarization resistance adapted for evaluating the corrosion of reinforced concrete on cooling towers. A simple operative measurement mode of Rp is proposed, adapted for cooling towers submitted to corrosion due to carbonation. By means of numerical experimentations, abacuses and correction laws are built involving the different influencing parameters: steel reinforcement's concrete cover, concrete resistivity and current intensity injected from the counter electrode. Finally, a first application of the proposed procedure for calculating the real value of Rp in laboratory conditions is presented. (authors)
An important mechanism sustaining the atmospheric "water tower" over the Tibetan Plateau
Xu, X.; Zhao, T.; Lu, C.; Guo, Y.; Chen, B.; Liu, R.; Li, Y.; Shi, X.
The Tibetan Plateau (TP), referred to as the "roof of the world", is also known as the "world water tower" because it contains a large amount of water resources and ceaselessly transports these waters to its surrounding areas. However, it is not clear how these waters are being supplied and replenished. In particular, how plausible hydrological cycles can be realized between tropical oceans and the TP. In order to explore the mechanism sustaining the atmospheric "water tower" over the TP, the relationship of a "heat source column" over the plateau and moist flows in the Asian summer monsoon circulation is investigated. Here we show that the plateau's thermal structure leads to dynamic processes with an integration of two couplings of lower convergence zones and upper divergences, respectively, over the plateau's southern slopes and main platform, which relay moist air in two ladders up to the plateau. Similarly to the CISK (conditional instability of the second kind) mechanism of tropical cyclones, the elevated warm-moist air, in turn, forces convective weather systems, hence building a water cycle over the plateau. An integration of mechanical and thermal TP forcing is revealed in relation to the Asian summer monsoon circulation knitting a close tie of vapor transport from tropical oceans to the atmospheric "water tower" over the TP.
Energy Technology Data Exchange (ETDEWEB)
Gary Vine
This report has been prepared for the Department of Energy, Office of Nuclear Energy (DOE-NE), for the purpose of providing a status report on the challenges and opportunities facing the U.S. commercial nuclear energy industry in the area of plant cooling water supply. The report was prompted in part by recent Second Circuit and Supreme Court decisions regarding cooling water system designs at existing thermo-electric power generating facilities in the U.S. (primarily fossil and nuclear plants). At issue in the courts have been Environmental Protection Agency regulations that define what constitutes �Best Technology Available� for intake structures that withdraw cooling water that is used to transfer and reject heat from the plant�s steam turbine via cooling water systems, while minimizing environmental impacts on aquatic life in nearby water bodies used to supply that cooling water. The report was also prompted by a growing recognition that cooling water availability and societal use conflicts are emerging as strategic energy and environmental issues, and that research and development (R&D) solutions to emerging water shortage issues are needed. In particular, cooling water availability is an important consideration in siting decisions for new nuclear power plants, and is an under-acknowledged issue in evaluating the pros and cons of retrofitting cooling towers at existing nuclear plants. Because of the significant ongoing research on water issues already being performed by industry, the national laboratories and other entities, this report relies heavily on ongoing work. In particular, this report has relied on collaboration with the Electric Power Research Institute (EPRI), including its recent work in the area of EPA regulations governing intake structures in thermoelectric cooling water systems.
PEP cooling water systems and underground piped utilities design criteria report
International Nuclear Information System (INIS)
This paper discusses the cooling systems required by the PEP Storage Ring. Particular topics discussed are: Cooling tower systems, RF cavity and vacuum chamber LCW cooling systems, klystron and ring magnet LLW cooling systems, Injection magnet LCW Cooling Systems; PEP interaction area detector LCW Cooling Systems; and underground piped utilities. 1 ref., 20 figs
Cooling water cleaning for steam turbine condensers
International Nuclear Information System (INIS)
The design of filters for cooling water cleaning for steam turbine condensers are described. It is pointed out that mounting of additional filters before the condensers particularly in case of contaminated water and crag development in the circulation system is economically justified. Additional filters are mounted in combination with the system of ball cleaning of condenser tubes as well as independently of it
Air and water cooled modulator
Birx, Daniel L. (Oakley, CA); Arnold, Phillip A. (Livermore, CA); Ball, Don G. (Livermore, CA); Cook, Edward G. (Livermore, CA)
A compact high power magnetic compression apparatus and method for delivering high voltage pulses of short duration at a high repetition rate and high peak power output which does not require the use of environmentally unacceptable fluids such as chlorofluorocarbons either as a dielectric or as a coolant, and which discharges very little waste heat into the surrounding air. A first magnetic switch has cooling channels formed therethrough to facilitate the removal of excess heat. The first magnetic switch is mounted on a printed circuit board. A pulse transformer comprised of a plurality of discrete electrically insulated and magnetically coupled units is also mounted on said printed board and is electrically coupled to the first magnetic switch. The pulse transformer also has cooling means attached thereto for removing heat from the pulse transformer. A second magnetic switch also having cooling means for removing excess heat is electrically coupled to the pulse transformer. Thus, the present invention is able to provide high voltage pulses of short duration at a high repetition rate and high peak power output without the use of environmentally unacceptable fluids and without discharging significant waste heat into the surrounding air.
Wind towers architecture, climate and sustainability
Bahadori, Mehdi N; Sayigh, Ali
This unique volume provides the only holistic treatment of wind towers, a core aspect of sustainable architecture in hot, arid climates. The authors explain how traditional incarnations of these structures provide significant decreases in energy consumption through their use of renewable wind resources to cool buildings and water storage facilities. Beginning with the underlying scientific principles, the design and operation of wind towers is explained in depth and suggestions for optimization are provided, supported by the authors' findings from recent analytical studies.
Fish-eye view from the water tower towards Jura
In the very front, the cooling plant for the ISR magnets followed by Storage (housing ISR electric generators)and CAO (Control Accelerator Operation) Buildings (Bld 378-377), and the main Building of the ISR Division (Bld 30). Behind stands the West Hall, followed along the neutrino beam line, by the BEBC building, the building housing the neutrino experiments WA1 and WA18, and the Gargamelle Building.
Materials for advanced water cooled reactors
International Nuclear Information System (INIS)
The current IAEA programme in advanced nuclear power technology promotes technical information exchange between Member States with major development programmes. The International Working Group on Advanced Technologies for Water Cooled Reactors recommended to organize a Technical Committee Meeting for the purpose of providing an international forum for technical specialists to review and discuss aspects regarding development trends in material application for advanced water cooled reactors. The experience gained from the operation of current water cooled reactors, and results from related research and development programmes, should be the basis for future improvements of material properties and applications. This meeting enabled specialists to exchange knowledge about structural materials application in the nuclear island for the next generation of nuclear power plants. Refs, figs, tabs
Meteorological effects of the cooling towers at the Oak Ridge Gaseous Diffusion Plant. II. Predictions of fog occurrence and drift deposition
International Nuclear Information System (INIS)
The frequency of occurrence of fogs and the rate of deposition of chromate due to emissions from the cooling towers at the Oak Ridge Gaseous Diffusion Plant are calculated. Observations of drift deposition agree fairly well with calculated values. A detailed summary of significant findings is given
Thermohydraulic relationships for advanced water cooled reactors
International Nuclear Information System (INIS)
This report was prepared in the context of the IAEA's Co-ordinated Research Project (CRP) on Thermohydraulic Relationships for Advanced Water Cooled Reactors, which was started in 1995 with the overall goal of promoting information exchange and co-operation in establishing a consistent set of thermohydraulic relationships which are appropriate for use in analyzing the performance and safety of advanced water cooled reactors. For advanced water cooled reactors, some key thermohydraulic phenomena are critical heat flux (CHF) and post CHF heat transfer, pressure drop under low flow and low pressure conditions, flow and heat transport by natural circulation, condensation of steam in the presence of non-condensables, thermal stratification and mixing in large pools, gravity driven reflooding, and potential flow instabilities. The objectives of the CRP are (1) to systematically list the requirements for thermohydraulic relationships in support of advanced water cooled reactors during normal and accident conditions, and provide details of their database where possible and (2) to recommend and document a consistent set of thermohydraulic relationships for selected thermohydraulic phenomena such as CHF and post-CHF heat transfer, pressure drop, and passive cooling for advanced water cooled reactors. Chapter 1 provides a brief discussion of the background for this CRP, the CRP objectives and lists the participating institutes. Chapter 2 provides a summary of important and relevant thermohydraulic phenomena for advanced water cooled reactors on the basis of previous work by the international community. Chapter 3 provides details of the database for critical heat flux, and recommends a prediction method which has been established through international co-operation and assessed within this CRP. Chapter 4 provides details of the database for film boiling heat transfer, and presents three methods for predicting film boiling heat transfer coefficients developed by institutes participating in this CRP. Chapter 5 compiles a range of pressure drop correlations, and reviews assessments of these relations and the resulting recommendations. Chapter 6 provides general remarks and conclusions, and comments on future research needs in thermohydraulics of advanced water cooled reactors
Organohalogen products from chlorination of cooling water at nuclear power stations
Energy Technology Data Exchange (ETDEWEB)
Bean, R.M.
Eight nuclear power units at seven locations in the US were studied to determine the effects of chlorine, added as a biocide, on the composition of cooling water discharge. Water, sediment and biota samples from the sites were analyzed for total organic halogen and for a variety of organohalogen compounds. Haloforms were discharged from all plants studied, at concentrations of a few ..mu..g/L (parts-per-billion). Evidence was obtained that power plants with cooling towers discharge a significant portion of the haloforms formed during chlorination to the atmosphere. A complex mixture of halogenated phenols was found in the cooling water discharges of the power units. Cooling towers can act to concentrate halogenated phenols to levels approaching those of the haloforms. Examination of samples by capillary gas chromatography/mass spectrometry did not result in identification of any significant concentrations of lipophilic base-neutral compounds that could be shown to be formed by the chlorination process. Total concentrations of lipophilic (Bioabsorbable) and volatile organohalogen material discharged ranged from about 2 to 4 ..mu..g/L. Analysis of sediment samples for organohalogen material suggests that certain chlorination products may accumulate in sediments, although no tissue bioaccumulation could be demonstrated from analysis of a limited number of samples. 58 references, 25 figures, 31 tables.
Coolant technology of water cooled reactors. V. 1: Chemistry of primary coolant in water cooled reactors
International Nuclear Information System (INIS)
This report is a summary of the work performed within the framework of the Coordinated Research Programme on Investigations on Water Chemistry Control and Coolant Interaction with Fuel and Primary Circuit Materials in Water Cooled Power Reactors organized by the IAEA and carried out from 1987 to 1991. It is the continuation of a programme entitled Reactor Water Chemistry Relevant to Coolant-Cladding Interaction (IAEA-TECDOC-429), which ran from 1981 to 1986. Subsequent meetings resulted in the title of the programme being changed to Coolant Technology of Water Cooled Reactors. The results of this Coordinated Research Programme are published in four volumes with an overview in the Technical Reports Series. The titles of the volumes are: Volume 1: Chemistry of Primary Coolant in Water Cooled Reactors; Volume 2: Corrosion in the Primary Coolant Systems of Water Cooled Reactors; Volume 3: Activity Transport Mechanisms in Water Cooled Reactors; Volume 4: Decontamination of Water Cooled Reactors. These publications should be of interest to experts in water chemistry at nuclear power plants, experts in engineering, fuel designers, research and development institutes active in the field and to consultants to these organizations. Refs, figs and tabs
Supercritical-pressure light water cooled reactors
Oka, Yoshiaki
This book focuses on the latest reactor concepts, single pass core and experimental findings in thermal hydraulics, materials, corrosion, and water chemistry. It highlights research on supercritical-pressure light water cooled reactors (SCWRs), one of the Generation IV reactors that are studied around the world. This book includes cladding material development and experimental findings on heat transfer, corrosion and water chemistry. The work presented here will help readers to understand the fundamental elements of reactor design and analysis methods, thermal hydraulics, materials and water
Subchannel analysis of supercritical water cooled reactors
International Nuclear Information System (INIS)
Subchannel analysis of supercritical water cooled reactors is carried out for estimating hot channel factors. A subchannel code for supercritical-water cooled reactors is developed. It is verified by comparing the calculated result of ASFRE-III code. The outlet coolant and cladding temperature are sensitive to the local power peaking and the assembly flow maldistribution because of the large coolant density change and high sensitivity of coolant temperature to the enthalpy change above the pseudo-critical temperature. However, it is shown that the effect is mitigated when the area of the peripheral subchannels is reduced and the mixing is enhanced 4-8 times of ordinary value at the grid spacers. The hot channel factor of a high temperature supercritical pressure light water cooled fast reactor (SCFR-H) is calculated using the uncertainties of Clinch River Breeder Reactor Plant (CRBRP). The factor is slightly higher than that of CRBRP because of the characteristics of supercritical water. The sensitivities of the hot channel factor is decreased for the SCFR-H fuel assembly in the core with blankets cooled by descending flow because of the higher inlet temperature of the driver fuel assemblies. (author)
Mixed oxide fuel for water cooled reactors
International Nuclear Information System (INIS)
The problems connected with introduction of plutonium extracted from spent fuels of operating NPPs into water cooled reactor fuel cycle are considered. The trends in formation of the World market of mixed fuel are illustrated taking as examples Great Britain and Japan
Analysis of water cooled reactors stability
International Nuclear Information System (INIS)
A model for stability analysis of non-boiling water cooled nuclear system is developed. The model is based on linear reactor kinetics and space averaged heat transfer in reactor and heat-exchanger. The transfer functions are defined and the analysis was applied to nuclear reactor RA at 'Boris Kidric' Institute - Vinca. (author)
Seismic analysis of two 1050 mm diameter heavy water upgrading towers for 235 MWe Kaiga Atomic Power Plant Site
International Nuclear Information System (INIS)
This report deals with the analysis carried out for the evaluation of earthquake induced stresses and deflections in two 1050 mm diameter heavy water upgrading towers for Kaiga Atomic Power Plant Site. The analysis of upgrading tower has been carried out for two mutually perpendicular horizontal excitations and one vertical excitation applied simultaneously. The upgrading towers have been analysed using beam model taking into account soil-structure interaction. Response spectrum analysis has been carried out using site spectra for 235 MWe Kaiga reactor site. The seismic analysis has been performed for both the towers with supporting structure along with concrete pedestals and raft foundation. The towers have been checked for its stability due to compressive stresses to avoid buckling so that the nearby safety related structures are not geopardised in the event of safe shutdown earthquake (SSE) loading. (author). 14 refs., 12 figs., 18 tabs
Seismic analysis of two 1050 mm diameter heavy water upgrading towers for 235 MWe Kakrapar Atomic Power Plant Site
International Nuclear Information System (INIS)
This report deals with the analysis carried out for the evaluation of earthquake induced stresses and deflections in two 1050 mm diameter heavy water upgrading towers for Kakrapar Atomic Power Plant Site. The analysis of upgrading tower has been carried out for two mutually perpendicular horizontal excitations and the vertical excitation. The upgrading towers have been analysed using beam model taking into account soil-structure interaction. response spectrum analysis has been carried out using site spectra for 235 MWe KAPP site. The seismic analysis has been carried out for both the towers with supporting structure along with concrete pedestals and raft foundation. The towers have been checked for their stability due to compressive stresses to avoid buckling so that the nearby safety related structures are not damaged in the event of SSE loading. (author). 13 refs., 11 figs., 14 tabs
Lifelines Episode 23: Cool Water
APS Communications Office (American Physiological Society Communications Office)
This is a free audio podcast from the American Physiological Society. Discussion questions, related research, and other teaching resources are available by clicking on the "collection" tab in the left hand column. Three physiologists tell us why the prescription �?drink when you are thirsty�? is usually the best guideline for deciding when and how much to drink. We will talk to Heinz Valtin of Dartmouth Medical School (retired); Mark Knepper, the chief of the Laboratory of Kidney & Electrolyte Metabolism of the National Heart Lung and Blood Institute; and Samuel Cheuvront, of the Thermal and Mountain Medicine Division of the U.S. Army Research Institute of Environmental Medicine about water consumption. They will answer the question: �?Must I drink 64 ounces of water each day?�? (Begins at 3:47) To read the review of the eight-by-eight rule by Heinz Valtin, click here: In the Buzz in Physiology, we look at studies involving a prosthetic device known as the Cheetah Flex Foot and whether it gives a runner who is a bilateral amputee an unfair advantage over limb-intact runners. We also summarize a study in mice in which adult bone marrow stem cells were used as a non-invasive therapy to repair cardiac tissue. And finally, we�?ll look at a study that finds that electro-acupuncture successfully reduced sympathetic nerve activity, normalized menstrual cycles and reduced testosterone in women with polycystic ovarian syndrome. (Begins at 1:05)
Reduction of Langelier index of cooling water by electrolytic treatment with stainless steel electrode
Scientific Electronic Library Online (English)
Rapeepat, Rungvavmanee; Chantaraporn, Phalakornkule.
Full Text Available The efficiency of electrolytic treatment in reducing the Langelier saturation index (LSI) of the cooling water from a cooling tower of a textile industry was investigated. Sacrificial anodes were employed which prevent obnoxious chlorine generation. A series of batch experiments using stainless stee [...] l electrodes were conducted with 4 different current densities (5, 7, 10 and 15 A/m�) and 6 different electrolysis times (20, 30, 40, 50, 60 and 70 min). The use of 7 A/m� for 50 min electrolysis time yielded a satisfactory efficiency in reducing the LSI index from 2.57 to zero, indicating that the treated water was of sufficient quality to be reused in the cooling process.
Simulaci�n de una Torre de Enfriamiento Mec�nica Comparada con Curvas Experimentales / Simulation of a Mechanical Cooling Tower Compared with Experimental Curves
Scientific Electronic Library Online (English)
Jader D, Alean; Gail A, Guti�rrez; Farid, Chejne; Marlon J, Bastidas.
Full Text Available El objetivo del trabajo es modelar y simular una torre de enfriamiento mec�nica forzada a escala piloto. Las variables f�sicas se correlacionaron a partir de la transferencia de calor y materia y los resultados de la simulaci�n son analizados mediante graficas que muestran la variaci�n de la humedad [...] , flujo de agua, calor latente, calor sensible, calor total, temperatura del agua y del aire. El coeficiente de transferencia de materia se obtuvo a partir de los datos experimentales y la soluci�n num�rica del modelo se obtuvo con el m�todo Runge-Kutta en Matlab. La verificaci�n de los resultados fue realizada, comparando las curvas simuladas con las curvas experimentales. Se concluye que la cercan�a entre las curvas depende del coeficiente de transferencia de materia. Abstract in english The objective of this work was the modeling and simulation of a pilot-scale mechanical enforced cooling tower. The physical variables were correlated from the heat and mass transfer and the simulation results were analyzed using graphs showing the change in humidity, water flow, latent heat, heat se [...] nsitive, total heat, water temperature and air. The mass transfer coefficient was obtained from experimental data and the numerical solution of the model was obtained using Runge-Kutta method in Matlab. Comparison between stimulation results and experimental data was done. It is concluded that the shape of the curves and the deviations of the simulated results depend on the mass transfer coefficient.
A supervisory control strategy for building cooling water systems for practical and real time applications
International Nuclear Information System (INIS)
This paper presents a model based supervisory control strategy for online control of building central cooling water systems to enhance their energy efficiency. The supervisory control strategy seeks the minimum energy input to provide adequate cooling energy for buildings, taking into account the characteristics and interactions of central cooling water systems as well as the requirements and constraints of practical application. Simplified semi-physical chiller and cooling tower models are used to predict the system energy performance and environment quality as well as the system response to changes of control settings. A hybrid optimization technique, namely the PMES (performance map and exhaustive search) based method, is developed and utilized to seek optimal solutions to the optimization problem. The control performance and energy performance of this model based supervisory control strategy are evaluated on the central cooling water system of a high rise commercial office building by comparing with that of the model based supervisory control strategy using a genetic algorithm (GA) as the optimization tool, and the performance map based near optimal control strategy as well as other conventional control strategies for cooling water systems in terms of energy efficiency, control accuracy, computational cost etc. The results showed that this strategy is more energy efficient and computational cost effective than other methods for online practical applications for online practical application
Water cooled FBNR nuclear reactor
International Nuclear Information System (INIS)
Full text: The world with its increasing population and the desire for a more equitable and higher standard of living, is in the search for energy that is abundant and does not contribute to the problem of global warming. The answer to this is a new paradigm in nuclear energy; i.e., through the innovative nuclear reactors that meet the IAEA's INPRO philosophies and criteria that will guarantee the generation of safe and clean energy. The emerging countries to nuclear energy that are not in hurry for energy and look into the future are looking into the participation in the development of such innovative nuclear reactors. They can start developing the non-nuclear components of such reactors in parallel with creating the nuclear infra-structures according to the guidelines of the IAEA suggested in its milestones document. In this way, they can benefit from numerous advantages that the development of a high technology can bring to their countries be it scientific, technological, economic or political. A solution to the present world economic crisis is investing in such projects that contribute to the real economy rather than speculative economy. This will help both local and world economy. One such innovative nuclear reactor is the FBNR that is being developed with the support of the IAEA in its program of Small Reactors Without On-site Refuelling. It is a small (70 MWe) reactor with simple design based on the proven PWR technology (www.sefidvash.net/fbnr). The simplicityy (www.sefidvash.net/fbnr). The simplicity in design and the world wide existence of water reactor technology, makes it a near term project compared to other future reactors. Small reactors are most adequate for both the developing and developed countries. They require low capital investment, and can be deployed gradually as energy demand calls for. The generation of energy at the local of consumption avoids high cost of energy transmission. The paradigm of economy of scale does not apply to the FBNR as it is a small reactor by its nature. The FBNR enjoys the economy of mass production. FBNR can serve a dual purpose plant generating electricity and producing desalinated water at the same time at lower cost. The FBNR has been evaluated by the IAEA's INPRO Methodology from the safety and nonproliferation points of view and is shown to be a fool proof reactor against nuclear proliferation and have inherent safety against any conceivable accident. The reactor has in its upper part the reactor core and a steam generator and in its lower part the fuel chamber. The core consists of two concentric perforated zircaloy tubes of 31 cm and 171 cm in diameters, inside which, during the reactor operation, the spherical fuel elements are held together by the coolant flow in a fixed bed configuration, forming a suspended fixed core. The coolant flows vertically up into the inner perforated tube and then, passing horizontally through the fuel elements and the outer perforated tube, enters the outer shell where it flows up vertically to the steam generator. The reserve fuel chamber is a 60 cm diameter tube made of high neutron absorbing alloy, which is directly connected underneath the core tube. The fuel chamber consists of a helical 40 cm diameter tube flanged to the reserve fuel chamber that is sealed by the national and international authorities. A grid is provided at the lower part of the tube to hold the fuel elements within it. A steam generator of the shell-and-tube type is integrated in the upper part of the module. A control rod can slide inside the centre of the core for fine reactivity adjustments. The reactor is provided with a pressurizer system to keep the coolant at a constant pressure. The pump circulates the coolant inside the reactor moving it up through the fuel chamber, the core, and the steam generator. Thereafter, the coolant flows back down to the pump through the concentric annular passage. At a flow velocity called terminal velocity, the water coolant carries the 15 mm diameter spherical fuel elements from the fuel chamber up into the core. A fixed s
Kinetic model for predicting the concentrations of active halogens species in chlorinated saline cooling waters. Final report
International Nuclear Information System (INIS)
A kinetic model has been developed for describing the speciation of chlorine-produced oxidants in seawater as a function of time. The model is applicable under a broad variety of conditions, including all pH range, salinities, temperatures, ammonia concentrations, organic amine concentrations, and chlorine doses likely to be encountered during power plant cooling water chlorination. However, the effects of sunlight are not considered. The model can also be applied to freshwater and recirculating water systems with cooling towers. The results of the model agree with expectation, however, complete verification is not feasible at the present because analytical methods for some of the predicted species are lacking
Kinetic model for predicting the concentrations of active halogens species in chlorinated saline cooling waters. Final report
Energy Technology Data Exchange (ETDEWEB)
Haag, W.R.; Lietzke, M.H.
A kinetic model has been developed for describing the speciation of chlorine-produced oxidants in seawater as a function of time. The model is applicable under a broad variety of conditions, including all pH range, salinities, temperatures, ammonia concentrations, organic amine concentrations, and chlorine doses likely to be encountered during power plant cooling water chlorination. However, the effects of sunlight are not considered. The model can also be applied to freshwater and recirculating water systems with cooling towers. The results of the model agree with expectation, however, complete verification is not feasible at the present because analytical methods for some of the predicted species are lacking.
Water treatment in HENDEL cooling water system, (part 1)
International Nuclear Information System (INIS)
This report describes a water treatment method for the HENDEL cooling water system. With the data of the corrosion occurred in the pressure vessels of heaters H31, H32 and a cooler C31 for the HENDEL M2-loop, water treatment methods were reviewed. The corrosion rate in these pressure vessels was max. 0.053 mm/year and the pittings found in the heaters H31 and H32 were 0.5 mm - 5 mm in diameter and max. 1.3mm in depth. Moreover, grooving corrosion, which was max. 1.7 mm in depth, was observed at the abutted seam of the heater H32. The main cause of these corrosions may be attributed to irregular operation cycles of the HENDEL cooling water system, and also to inadequacy of water quality for using corrosion inhibitors. By adding polyphosphate with Zn2+ and dispersing agent in corrosion inhibitor, much improvement in preventing corrosion was verified. (author)
Review of high temperature water and steam cooled reactor concepts
International Nuclear Information System (INIS)
This review summarizes design concepts of supercritical-pressure water cooled reactors (SCR), nuclear superheaters and steam cooled fast reactors from 1950's to the present time. It includes water moderated supercritical steam cooled reactor, SCOTT-R and SC-PWR of Westinghouse, heavy water moderated light water cooled SCR of GE, SCLWR and SCFR of the University of Tokyo, B-500SKDI of Kurchatov Institute, CANDU-X of AECL, nuclear superheaters of GE, subcritical-pressure steam cooled. FBR of KfK and B and W, Supercritical-pressure steam cooled FBR of B and W, subcritical-pressure steam cooled high converter by Edlund and Schultz and subcritical-pressure water-steam cooled FBR by Alekseev. (author)
Statistical performance analysis of salt water cooled pressurized water reactors
International Nuclear Information System (INIS)
Pressurized water reactors (PWRs) using salt or brackish cooling water are found to have significant long-term decreases in capacity factors and increases in forced outage rates (FORs) due to equipment failures and maintenance needs. Larger units have significantly lower capacity factors and higher FORs. The significance and magnitude of this correlation increases with unit age. Post-Three Mile Island effects are controlled for
Cooling-water amounts, temperature, and the environment
International Nuclear Information System (INIS)
The release of heat from power plants into a water can take place with relative small quantities of cooling water, highly warmed up accordingly, or with large quantities of cooling water slightly warmed up. The utilization of cooling water is bound to certain guidelines established by the authorities. With the intention to protect the environment, the admissable temperatures and warming-up have been strictly limited by the authorities. In the Netherlands, we have presently temporary cooling water guidelines which allow a max. temperature of the cooling water in the cooling cycle of 300C and a maximum admissible temperature rise in the condenser between 70C during summer and 150C during winter. It has also been determined in these requirements how much cooling water at least has to be used to discharge a specified quantity of heat. Plankton, spawn and young fish are dragged with the cooling water. Harm to these organisms can be caused mechanically by pumps, sieves and the condenser or they can be harmed by the temperature rise in the condenser. Investigations showed that mechanical harm to spawn and young fish in the cooling water flow should not be ignored, and that detectable harm to plankton organisms takes place only at water temperatures above 320C. The cooling water consumption can therefore be optimised as follows: The solution of a greater temperature increase and a slightly higher value for the temperature maximum caigher value for the temperature maximum can reduce the cooling water quantity. This reduction of the cooling water quantity reduces the destruction of the fish quantity, which gets into the cooling water system, especially during the summer. If the temperature rise and the temperature itself are not selected too high, the destruction of fish may be reduced without causing serious damage to the plankton. (orig.)
Heat dissipation in water-cooled reflectors
Kozai, Toyoki
The energy balance of a lamp varies with the thermal and optical characteristics of the reflector. The photosynthetic radiation efficiency of lamps, defined as input power divided by photosynthetically active radiation (PAR, 400-700 nm) emitted from the lamp ranges between 0.17 and 0.26. The rest of the energy input is wasted as longwave (3000 nm and over) and non-PAR shortwave radiation (from 700 nm to 3000 nm), convective, and conductive heat from the lamp, reflector, and ballast, and simply for increasing the cooling load. Furthermore, some portion of the PAR is uselessly absorbed by the inner walls, shelves, vessels, etc. and some portion of the PAR received by the plantlets is converted into sensible and latent heat. More than 98% of the energy input is probably converted into heat, with only less than 2% of the energy input being converted into chemical energy as carbohydrates by photosynthesis. Therefore, it is essential to reduce the generation of heat in the culture room in order to reduce the cooling load. Through use of a water-cooled reflector, the generation of convective and conductive heat and longwave radiation from the reflector can be reduced, without reduction of PAR.
Comparative validation of three water cooling coil models
Gendebien, Samuel; Bertagnolio, Ste?phane; Lemort, Vincent
Water cooling coils are widely used in common HVAC systems. Accurate and robust cooling coil simulation models are required to perform reliable calculations of building cooling needs. Many different cooling coil simulation models were developed during the last decades. The most commonly used cooling coil models are presented and compared in terms of implementation in the first part of the paper. A simplified variable boundary model is presented and comparatively and empirically validated to t...
Electrochemistry of Water-Cooled Nuclear Reactors
International Nuclear Information System (INIS)
This project developed a comprehensive mathematical and simulation model for calculating thermal hydraulic, electrochemical, and corrosion parameters, viz. temperature, fluid flow velocity, pH, corrosion potential, hydrogen injection, oxygen contamination, stress corrosion cracking, crack growth rate, and other important quantities in the coolant circuits of water-cooled nuclear power plants, including both Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). The model is being used to assess the three major operational problems in Pressurized Water Reactors (PWR), which include mass transport, activity transport, and the axial offset anomaly, and provide a powerful tool for predicting the accumulation of SCC damage in BWR primary coolant circuits as a function of operating history. Another achievement of the project is the development of a simulation tool to serve both as a training tool for plant operators and as an engineering test-bed to evaluate new equipment and operating strategies (normal operation, cold shut down and others). The development and implementation of the model allows us to estimate the activity transport or ''radiation fields'' around the primary loop and the vessel, as a function of the operating parameters and the water chemistry
Electrochemistry of Water-Cooled Nuclear Reactors
Energy Technology Data Exchange (ETDEWEB)
Macdonald, Dgiby; Urquidi-Macdonald, Mirna; Pitt, Jonathan
This project developed a comprehensive mathematical and simulation model for calculating thermal hydraulic, electrochemical, and corrosion parameters, viz. temperature, fluid flow velocity, pH, corrosion potential, hydrogen injection, oxygen contamination, stress corrosion cracking, crack growth rate, and other important quantities in the coolant circuits of water-cooled nuclear power plants, including both Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). The model is being used to assess the three major operational problems in Pressurized Water Reactors (PWR), which include mass transport, activity transport, and the axial offset anomaly, and provide a powerful tool for predicting the accumulation of SCC damage in BWR primary coolant circuits as a function of operating history. Another achievement of the project is the development of a simulation tool to serve both as a training tool for plant operators and as an engineering test-bed to evaluate new equipment and operating strategies (normal operation, cold shut down and others). The development and implementation of the model allows us to estimate the activity transport or "radiation fields" around the primary loop and the vessel, as a function of the operating parameters and the water chemistry.
Repair criteria and methods of repair for concrete structures of nuclear power plants - Particular application on natural draught cooling towers in belgium
International Nuclear Information System (INIS)
A previous paper was presented at the OCDE Workshop held 22-23 March 2000 in Brussels explaining different aspects of the techniques used for 'Instrumentation and monitoring of natural draught cooling towers in Belgium'. These monitoring and preventive techniques are now applied in Belgium since already more then 10 years by Tractebel on the towers of the nuclear plants. These huge constructions have to sustain considerable physical, chemical and biological loads. As one can figure out, and as years go by, these inspections showed deterioration of which type, progress, quantity eventually led to the need of repairing these structures. The present paper goes over 4 main different sorts of defects (beam supports breaking, fast carbonation rate, concrete porosity, and a series of local deteriorations like insufficient concrete cover, cracking, gravel pockets, corroded reinforcement) encountered on 3 cooling towers situated in Belgium, and affecting the shell as well as the inner structures. The diagnosis, the choice of the appropriate repair techniques and products which will avoid having to face much higher costs in the future are explained. It also gives an illustration of the works carried on site and points out the uncommon and complex aspects the treatment of such a construction implies (planning, both horizontal and vertical curved shape, works at great height,...). (author)
Reuso de efluentes em torres de resfriamento - estudo conceitual: Aeroporto Internacional do Rio de Janeiro - doi: 10.4025/actascitechnol.v32i3.865 Water reuse for cooling towers � conceptual study: Rio de Janeiro International Airport - doi: 10.4025/actascitechnol.v32i3.865
Directory of Open Access Journals (Sweden)
Bernardo Jos� Farah Machado
Full Text Available O reuso de �gua � ferramenta valiosa na gest�o da �gua, que promove a otimiza��o da utiliza��o do recurso desta, que reduz e, muitas vezes, at� elimina os impactos no meio ambiente. Neste trabalho foi investigada a composi��o do efluente secund�rio da esta��o de tratamento de efluentes (ETE APOIO do Aeroporto Internacional do Rio de Janeiro, com o objetivo de propor o processo adequado � reutiliza��o deste efluente como �gua de reposi��o nas torres de resfriamento desse Aeroporto. Com base nas an�lises de c�tions, �nions, DBO e DQO, verificou-se o par�metro SDT � Cl- como cr�tico para processamento do efluente. Foi proposta uma sequ�ncia para reutiliza��o do efluente que continha o tratamento de osmose inversa, o custo do m3 produzido por essa sequ�ncia foi estimado em R$ 2,90 m-3.Water reuse is an important tool in water management; it is a concept that promotes optimization of the water resource, reducing and often even eliminating environmental impacts. In this work, the composition of a secondary effluent (from the effluent treatment station (ETE APOIO at Rio de Janeiro International Airport was analyzed, with the aim of determining an adequate process for the reutilization of this effluent as replacement cooling water. Chemical analyses such as cation and anion analysis, BOD and COD were performed. Based on these analyses, it was found that TDS � Cl- was the critical parameter for effluent processing. A treatment system was proposed for effluent reuse including reverse osmosis; the cost estimate per m3 produced by this system was R$ 2.90 m-3.
Fast reactor cooled by supercritical light water
Energy Technology Data Exchange (ETDEWEB)
Ishiwatari, Yuki; Mukouhara, Tami; Koshizuka, Seiichi; Oka, Yoshiaki [Tokyo Univ., Nuclear Engineering Research Lab., Tokai, Ibaraki (Japan)
This report introduces the result of a feasibility study of a fast reactor cooled by supercritical light water (SCFR) with once-through cooling system. It is characterized by (1) no need of steam separator, recirculation system, or steam generator, (2) 1/7 of core flow rate compared with BWR or PWR, (3) high temperature and high pressure permits small turbine and high efficiency exceeding 44%, (4) structure and operation of major components are already experienced by LWRs or thermal power plants. Modification such as reducing blanket fuels and increasing seed fuels are made to achieve highly economic utilization of Pu and high power (2 GWe). The following restrictions were satisfied. (1) Maximum linear heat rate 39 kW/m, (2) Maximum surface temperature of Inconel cladding 620degC, (3) Negative void reactivity coefficient, (4) Fast neutron irradiation rate at the inner surface of pressure vessel less than 2.0x10{sup 19} n/cm{sup 2}. Thus the high power density of 167 MW/m{sup 3} including blanket is thought to contributes economy. The high conversion is attained to be 0.99 Pu fission residual rate by the outer radius of fuel rod of 0.88 mm. The breeding of 1.034 by Pu fission residual rate can be achieved by using briquette (tube-in-shell) type fuel structure. (K. Tsuchihashi)
Technological readiness of evolutionary water cooled reactors
International Nuclear Information System (INIS)
Nuclear energy has evolved to a mature industry that supplies over 16% of the world's electricity, and it represents an important option for meeting the global energy demands of the coming century in an environmentally acceptable manner. New, evolutionary water cooled reactor designs that build on successful performance of predecessors have been developed; these designs have generally been guided by wishes to reduce cost, to improve availability and reliability, and to meet increasingly stringent safety objectives. These three aspects are important factors in what has been called technological readiness for an expanded deployment of nuclear power; a major increase in utilization of nuclear power will only occur if it is economically competitive, and meets safety expectations. To this end, the industry will also have to maintain or improve the public perception of nuclear power as a benign, economical and reliable energy source. (author)
Deposit control in process cooling water systems
International Nuclear Information System (INIS)
In order to achieve efficient heat transfer in cooling water systems, it is essential to control the fouling of heat exchanger surfaces. Solubilities of scale forming salts, their growth into crystals, and the nature of the surfaces play important roles in the deposition phenomenon. Condensed phosphates, organic polymers and compounds like phosphates are effective in controlling deposition of scale forming salts. The surface active agents inhibit crystal growth and modify the crystals of the scale forming salts, and thus prevent deposition of dense, uniformly structured crystalline mass on the heat transfer surface. Understanding the mechanism of biofouling is essential to control it by surface active agents. Certain measures taken in the plant, such as back flushing, to control scaling, sometimes may not be effective and can be detrimental to the system itself. (author)
Sea water take-up facility for cooling reactor auxiliary
International Nuclear Information System (INIS)
The present invention provides an improvement of a cooling sea water take-up facility for cooling auxiliary equipments of nuclear power plant. Namely, an existent sea water take-up facility for cooling reactor auxiliary equipments has at least two circulation water systems and three independent sea water systems for cooling reactor auxiliary equipments. In this case, a communication water channel is disposed, which connects the three independent sea water systems for cooling reactor auxiliary equipments mutually by an opening/closing operation of a flow channel partitioning device. With such a constitution, even when any combination of two systems among the three circulation water systems is in inspection at the same time, one system for cooling the reactor auxiliary equipments can be kept operated, and one system is kept in a stand-by state by the communication water channel upon periodical inspection of water take-up facility for cooling the auxiliary equipments. As a result, the sea water take-up facility for cooling auxiliary equipments of the present invention have operation efficiency higher than that of a conventional case while keeping the function and safety at the same level as in the conventional case. (I.S.)
The role of water in cooling ignimbrites
Keating, Gordon N.
A summary of observational literature on ignimbrites provides the basis for the development of a two-dimensional numerical model of ignimbrite cooling processes. Factors include emplacement conditions, post-emplacement processes, and the nature and timing of interactions with water during cooling. The model uses the multiphase finite element heat and mass transfer (FEHM) code, which has been enhanced to handle conditions up to 1500 �C. The instantaneous emplacement of a 750 �C ignimbrite with internal gas pressures of up to 0.5 MPa (lithostatic) has a great effect on the variably saturated substrate. A water table present within a few tens of meters of the base of the ignimbrite produces a region of high pressure and temperature that exists for about 20 years, driving vapor upward through the ignimbrite as diffuse flow and in gas escape structures and enhancing cooling at the base of the ignimbrite. Variations in initial gas pressure between atmospheric and lithostatic conditions have little effect on the thermal evolution. The results of the numerical modeling of 20- and 40-m-thick ignimbrites indicate that, even for moderate pore water saturations in the substrate, vaporization and resultant pressurization may exceed lithostatic confining pressures in the upper substrate and basal ignimbrite, and explosive pressure release may occur, resulting in the development of discrete fumarole conduits or phreatic explosions. The likelihood for explosive pressure release appears to be greater when the nominal ignimbrite thickness is on the order of the depth of a buried valley. The pressure buildup is enhanced by the geometry of the ignimbrite-substrate interface, especially at convex corners such as on the edges of a buried valley. The boiling zones at the top and bottom of a cooling ignimbrite involve the development of a heat-pipe, which provides an efficient means of transporting heat from the superheated tephra out tens of meters into the ambient environment. The predicted temporal evolution of temperature, pressure, and vapor flow in a 40-m ignimbrite support the conceptual model of degassing, welding and compaction, devitrification, and alteration occurring concomitantly in the first several years after emplacement and driven in part by production and migration of meteoric steam. This vapor flowing through the ignimbrite matrix at 5�10 -5 kg s -1 in the first 10 years enhances devitrification in any part of the ignimbrite above the base in nonwelded deposits. In the case where welding occurs, lower permeability limits the diffuse flow of gas upward through the ignimbrite from the region of boiling and pore pressurization at the base, and enhanced devitrification in the basal parts of the ignimbrite may occur where pore vapors circulate in abundance. Immediately above the welded zone, a devitrified horizon may develop where the upper boiling/condensation zone and perched meteoric infiltration results in enhanced saturations.
Technical analysis of a river basin-based model of advanced power plant cooling technologies for mitigating water management challenges
International Nuclear Information System (INIS)
Thermoelectric power plants require large volumes of water for cooling, which can introduce drought vulnerability and compete with other water needs. Alternative cooling technologies, such as cooling towers and hybrid wet-dry or dry cooling, present opportunities to reduce water diversions. This case study uses a custom, geographically resolved river basin-based model for eleven river basins in the state of Texas (the Brazos and San Jacinto-Brazos, Colorado and Colorado-Brazos, Cypress, Neches, Nueces, Red, Sabine, San Jacinto, and Trinity River basins), focusing on the Brazos River basin, to analyze water availability during drought. We utilized two existing water availability models for our analysis: (1) the full execution of water rights-a scenario where each water rights holder diverts the full permitted volume with zero return flow, and (2) current conditions-a scenario reflecting actual diversions with associated return flows. Our model results show that switching the cooling technologies at power plants in the eleven analyzed river basins to less water-intensive alternative designs can potentially reduce annual water diversions by 247-703 million m3-enough water for 1.3-3.6 million people annually. We consider these results in a geographic context using geographic information system tools and then analyze volume reliability, which is a policymaker's metric that indicates the percentage of total demand actually supplied over a given period. This geogry supplied over a given period. This geographic and volume reliability analysis serves as a measure of drought susceptibility in response to changes in thermoelectric cooling technologies. While these water diversion savings do not alleviate all reliability concerns, the additional streamflow from the use of dry cooling alleviates drought concerns for some municipal water rights holders and might also be sufficient to uphold instream flow requirements for important bays and estuaries on the Texas Gulf coast.
International Nuclear Information System (INIS)
Power plant cooling is the major use of water at nearly all thermo-electric generating plants. The withdrawal, consumption and discharge of water for power production raises some of the most contentious siting issues for new plants. This paper will review the major cooling system types and discuss the advantages and disadvantages of each from both the cost/performance and environmental effects viewpoints. Historically, the preferred cooling system for large plants was once-through cooling. In the past few decades, the trend has been to closed-cycle wet cooling to reduce the environmental effects of heated water discharges and large withdrawal rates. More recently, the use of dry and hybrid cooling has been chosen at many sites. The application of dry and hybrid cooling to nuclear plants can introduce design problems not encountered in fossil plants and may lead to the consideration of indirect dry cooling and the reintroduction of natural draft cooling towers. In addition, a number of emerging technologies such as the recovery of water from the plumes of wet cooling towers, the use of inlet air sprays to enhance the performance of dry systems and some innovative approaches to the use of alternative (non-fresh) water supplies may find application in the near future. Some possible research directions for future cooling system improvements are considered. (authors)
Get a better reading on scaling tendency of cooling water
International Nuclear Information System (INIS)
The equilibrium pH index is proposed as a replacement for the Langelier Saturation Index (LSI) and the Ryzner's Stability Index (RSI) as a method for utility power stations to predict whether their cooling water will form calcium carbonate scale in their condensers. Both the LSI and RSI are explained, and it is seen that the interpretation of scale formation is in error and causes serious corrosion in the cooling system. Only PSI correctly identifies the conditions of the cooling water. By using the PSI, acid requirements have decreased, water savings accrue, and cooling system components are receiving better protection. PSI is also displacing LSI and RSI as a scaling index
New system of cooling download Arrocampo. Project TEVA
International Nuclear Information System (INIS)
Project TEVA The new system is basically a mechanical forced-cooling tower, a system of pumping water from Arrocampo, pipes and valves supply a collection basin water tower, a channel to drain the existing auxiliary spillway own shot dam and a new power line from the Central.
Equipment cooling system and sea water cooling system in the after-heat removal system
International Nuclear Information System (INIS)
Purpose: To improve the reliability of an emergency diesel generator in the after-heat removal system and of pumps for the equipment cooling system and the sea water cooling system, as well as improve the reliability of the after-heat removal system upon accident to thereby facilitate the cooling for a long time. Constitution: The after-heat removal system of a BWR type reactor actuated upon accident comprises each two equipment cooling systems and sea water cooling systems. For each of the two systems of the equipment cooling system and the sea water cooling system in the after-heat removal system, are provided pipeways for connecting the upstream side of the pumps, pipeways for connecting the downstream sides of the pumps, a pump equipped with an emergency diesel generator independent from the two systems connected with the pipeways and check valves provided at the upstream and the downstream of the pumps. These equipments are controlled in accordance with low pressure water injection mode, reactor container spray mode, pool water cooling mode, steam condensation mode and shutdown cooling mode. (Aizawa, K.)
A heat dissipating model for water cooling garments
Yang Kai; Jiao Ming-Li; Liu Zhe; Zhang Wei-Yuan
A water cooling garment is a functional clothing used to dissipate human body�s redundant energy in extravehicular environment or other hot environment. Its heat dissipating property greatly affects body�s heat balance. In this paper, a heat dissipating model for the water cooling garment is established and verified experimentally using the experimental thermal-manikin.
Water cooled modular power reactor (VBER-300)
International Nuclear Information System (INIS)
VBER-300 is the Russian abbreviation for a nuclear power plant (NPP) with a light water cooled modular power reactor of 300 MW(e). The VBER-300 is a NPP with a modular pressurized water reactor developed on the basis of shipboard reactor technologies. The Russian Federation has a solid experience in the design and technology development, as well as in the construction and operation of such reactors. The high quality of shipboard modular design reactors is guaranteed by the long-term accident-free operation of Russian nuclear-powered icebreakers 'Arktika', 'Sibir', 'Rossia' and others, under more exacting conditions than those of land-based nuclear power plants (NPPs). Modular pressurized water reactors are based on the most highly developed reactor technologies, examined and proven by the successful operating experiences of shipboard nuclear power plants. The operating experience of shipboard reactors exceeds 6000 reactor-years. This experience is comparable to that of the nuclear power industries in such industrialized countries as France and Japan. Long-term experience in the design, construction and operation of shipboard reactors and the results of R and D for their design validation, the technological base and the personnel potential of Russian enterprises are the background to create highly-reliable nuclear power sources for NPPs. The VBER-300 plant design is a result of the evolution of shipboard modular reactors. The thermal power increase is due to an increashermal power increase is due to an increase in mass and overall dimensions keeping a reactor plant pattern and the main design solutions as close as possible to those of shipboard reactors. The design was developed using operating experience with the VVER-type reactors and achievements in the field of nuclear power plant safety. The principal stakeholders are Russian research and design organizations: OKB Mechanical Engineering (OKBM, Nizhny Novgorod), Russian Research Centre 'Kurchatov Institute' (RRC 'Kurchatov Institute', Moscow), Scientific-Research and Design Institute 'Atomenergoproekt' (NIAEP, Nizhny Novgorod), and Public Company 'Lazurit', Nizhny Novgorod
Validation of the kinetic model for predicting the composition of chlorinated water discharged from power plant cooling systems
International Nuclear Information System (INIS)
The purpose of this report is to present a validation of a previously described kinetic model which was developed to predict the composition of chlorinated fresh water discharged from power plant cooling systems. The model was programmed in two versions: as a stand-alone program and as a part of a unified transport model developed from consistent mathematical models to simulate the dispersion of heated water and radioisotopic and chemical effluents from power plant discharges. The results of testing the model using analytical data taken during operation of the once-through cooling system of the Quad Cities Nuclear Station are described. Calculations are also presented on the Three Mile Island Nuclear Station which uses cooling towers
Technology for Water Treatment (National Water Management)
The buildup of scale and corrosion is the most costly maintenance problem in cooling tower operation. Jet Propulsion Laboratory successfully developed a non-chemical system that not only curbed scale and corrosion, but also offered advantages in water conservation, cost savings and the elimination of toxic chemical discharge. In the system, ozone is produced by an on-site generator and introduced to the cooling tower water. Organic impurities are oxidized, and the dissolved ozone removes bacteria and scale. National Water Management, a NASA licensee, has installed its ozone advantage systems at some 200 cooling towers. Customers have saved money and eliminated chemical storage and discharge.
Storage of HLW in engineered structures: air-cooled and water-cooled concepts
International Nuclear Information System (INIS)
A comparative study on an air-cooled and a water-cooled intermediate storage of vitrified, highly radioactive waste (HLW) in overground installations has been performed by Nukem and Belgonucleaire respectively. In the air-cooled storage concept the decay heat from the storage area will be removed using natural convection. In the water-cooled storage concept the decay heat is carried off by a primary and secondary forced-cooling system with redundant and diverse devices. The safety study carried out by Nukem used a fault tree method. It shows that the reliability of the designed water-cooled system is very high and comparable to the inherent, safe, air-cooled system. The impact for both concepts on the environment is determined by the release route, but even during accident conditions the release is far below permissible limits. The economic analysis carried out by Belgonucleaire shows that the construction costs for both systems do not differ very much, but the operation and maintenance costs for the water-cooled facility are higher than for the air cooled facility. The result of the safety and economic analysis and the discussions with the members of the working group have shown some possible significant modifications for both systems, which are included in this report. The whole study has been carried out using certain national criteria which, in certain Member States at least, would lead to a higher standard of safety than can be justified on any social, political or economic grounds
A multi-layered model for collapse analysis of large reinforced concrete natural-draft cooling towers. Ein Stahlbeton-Mehrschichten-Modell zur Kollapsanalyse grosser Naturzugkuehltuerme
Energy Technology Data Exchange (ETDEWEB)
Zhuang Yiqun.
The modelling of the material behavior of the reinforced concrete is managed by utilizing Bazant's plastic-fracturing theory for the concrete and an elasto-plastic material law, including the Bauschinger effect, for the rebar. The theoretical basis of the model is the shear deformation theory as well as the Kirchhoff-Love theory in the sense of Donnell-Marguerre's approach. To consider the discontinuity of strains in the case of the cracked concrete, mixed FE-models that are based on Hellinger-Reissner's variational principle and its modified version are developed. At last, the damage evolution of a large natural draught cooling tower until collapse is traced numerically. The collapse analysis was performed under dead load and quasi-static wind action. The collapse simulation demonstrates the weakening of the cooling tower under the load combinations according to Euro-code and BTR taking the variability of the material properties into account. (orig./HP).
Model-based advanced water cooled reactor
International Nuclear Information System (INIS)
At present, no easy-to-maintain, high-temperature capable monitoring and control systems exist for Generation-IV reactors. Since these reactors are planned to operate with temperature above 1000 deg. C and high neutron flux, accurate measurements are needed to identify hot spots, control in-core power distribution and other parameters that are critical to the safe operation of the reactors. Also, an on-line gamma-spectroscopy approach is the most accurate method to perform the fuel monitoring, especially for reactors with on-line refueling. It is important to operate a reactor in the minimum fuel loading state so that any physical changes in configuration are self-correcting. The preliminary analysis shows that modification of current water-cooled reactors is cheaper and safer than storing spent fuel. In addition, our test facilities will either use the General Atomics; inherently safe fuel technology or will not employ any fissionable material. Relationships will be developed between the key design parameters including system size, power level, and neutron flux. The advanced annular fuel design could be initiated in collaboration with Massachusetts Institute of Technology, as was previously discussed among several MIT researchers
High conversion type light water cooled reactor
International Nuclear Information System (INIS)
Purpose: To ensure the fuel rod integrity without complicating the fuel design. Constitution: In a high conversion type light water cooled reactor having, arranged therein, a plurality of fuel assemblies each comprising a channel box of a hexagonal cross section in which a plurality of fuel rods are disposed in a trigonal lattice-like configuration, the fuel assemblies are so arranged that a trigonal cross sectional scope is defined between each of adjacent fuel assemblies. It is possible to control the size of the trigonal space and also change the cross section of the control rod by adjusting the length of the side of the adjacent hexagonal shape. In this way, the control rod and the power monitoring device can be disposed to the outside of the fuel assemblies, by which the problem in the reduction of the integrity accompanying the displacement of the fuel rod can be avoided and the fuel rods in the fuel assembly can be made into a uniform constitution to render the power distribution more uniform. Accordingly, the power peaking coefficient is lowered and the operation margin to the linear power density limit can be increased. (Kamimura, M.)
Study on water cooled high conversion reactor
International Nuclear Information System (INIS)
As a part of study on advanced reactors for the future, conceptual design of high conversion water cooled reactors is being studied, aiming at the contribution to nuclear fuel cycle by the LWR technology, since the utilization of LWRs will extend over a long period of time . We are studying on the reactor core concepts for BWR and PWR reactor systems. As for BWR system, three types of reactor cores are investigating for three different design goals; long operation period, high conversion ratio and high applicability for the existing BWR system. In all the cases, we have obtained a fair prospect of a large core concept with a capacity of 1,000 MWe class having negative void reactivity coefficient. This study is a part of JAERI-JAPCO (Japan Atomic Power Company) cooperative studies. Various kinds of conceptual designs will be created until the end of FY 1999. The designs will be checked and reviewed at that time, then experimental studies on the realization of the concepts will start with further design works from FY 2000. (author)
Water cooled reactor technology: Safety research abstracts no. 1
International Nuclear Information System (INIS)
The Commission of the European Communities, the International Atomic Energy Agency and the Nuclear Energy Agency of the OECD publish these Nuclear Safety Research Abstracts within the framework of their efforts to enhance the safety of nuclear power plants and to promote the exchange of research information. The abstracts are of nuclear safety related research projects for: pressurized light water cooled and moderated reactors (PWRs); boiling light water cooled and moderated reactors (BWRs); light water cooled and graphite moderated reactors (LWGRs); pressurized heavy water cooled and moderated reactors (PHWRs); gas cooled graphite moderated reactors (GCRs). Abstracts of nuclear safety research projects for fast breeder reactors are published independently by the Nuclear Energy Agency of the OECD and are not included in this joint publication. The intention of the collaborating international organizations is to publish such a document biannually. Work has been undertaken to develop a common computerized system with on-line access to the stored information
Operating manual for the Tower Shielding Facility
International Nuclear Information System (INIS)
This manual provides information necessary to operate and perform maintenance on the reactor systems and all equipment or systems which can affect their operation or the safety of personnel at the Tower Shielding Facility. The first four chapters consist of introductory and descriptive material of benefit to personnel in training, the qualifications required for training, the responsibilities of the personnel in the organization, and the procedures for reviewing proposed experiments. Chapter 8, Emergency Procedures, is also a necessary part of the indoctrination of personnel. The procedures for operation of the Tower Shielding Reactor (TSR-II), its water cooling system, and the main tower hoists are outlined in Chapters 5, 6, and 7. The Technical Specification surveillance requirements for the TSR-II are summarized in Chapter 9. The maintenance and calibration schedule is spelled out in Chapter 10. The procedures for assembly and disassembly of the TSR-II are outlined in Chapter 11
Results of cooling of dies with water mist
Directory of Open Access Journals (Sweden)
R. W?adysiak
Full Text Available Purpose: Intensification of die casting of car silumins wheels with use of the water mist instead of compressed air dies cooling in low pressure casting process were presented in the paper.Design/methodology/approach: Examinations of casting process parameters were carried out on the industrial workstation of casting car wheels under the low pressure and also with Magma computer simulating system.Findings: The temperature and the range of its variation were presented in characteristic points of the casting and the cooled die with use the compressed air and with the water mist. A scheme of the device for generating the water mist cooling the die and also the pictures of simulation of wheels casting process for researched cooling methods was given.Research limitations/implications: The manufacturing technologies with the permanent mould.Practical implications: Using the water mist to cooling of dies in die casting and low pressure casting process to intensify of cooling the die and to reduce the amount of casting spoilage.Originality/value: Using the water mist to cooling increases intensity of cooling of the die and the cast. It makes shorter the cycle of casting process as well as reduces the porosity of casts and increases mechanical properties: Rp0,2, Rm, A5 and HB.
Use of Produced Water in Recirculated Cooling Systems at Power Generating Facilities
Energy Technology Data Exchange (ETDEWEB)
C. McGowin; M. DiFilippo; L. Weintraub
Tree ring studies indicate that, for the greater part of the last three decades, New Mexico has been relatively 'wet' compared to the long-term historical norm. However, during the last several years, New Mexico has experienced a severe drought. Some researchers are predicting a return of very dry weather over the next 30 to 40 years. Concern over the drought has spurred interest in evaluating the use of otherwise unusable saline waters to supplement current fresh water supplies for power plant operation and cooling and other uses. The U.S. Department of Energy's National Energy Technology Laboratory sponsored three related assessments of water supplies in the San Juan Basin area of the four-corner intersection of Utah, Colorado, Arizona, and New Mexico. These were (1) an assessment of using water produced with oil and gas as a supplemental supply for the San Juan Generating Station (SJGS); (2) a field evaluation of the wet-surface air cooling (WSAC) system at SJGS; and (3) the development of a ZeroNet systems analysis module and an application of the Watershed Risk Management Framework (WARMF) to evaluate a range of water shortage management plans. The study of the possible use of produced water at SJGS showed that produce water must be treated to justify its use in any reasonable quantity at SJGS. The study identified produced water volume and quality, the infrastructure needed to deliver it to SJGS, treatment requirements, and delivery and treatment economics. A number of produced water treatment alternatives that use off-the-shelf technology were evaluated along with the equipment needed for water treatment at SJGS. Wet surface air-cooling (WSAC) technology was tested at the San Juan Generating Station (SJGS) to determine its capacity to cool power plant circulating water using degraded water. WSAC is a commercial cooling technology and has been used for many years to cool and/or condense process fluids. The purpose of the pilot test was to determine if WSAC technology could cool process water at cycles of concentration considered highly scale forming for mechanical draft cooling towers. At the completion of testing, there was no visible scale on the heat transfer surfaces and cooling was sustained throughout the test period. The application of the WARMF decision framework to the San Juan Basis showed that drought and increased temperature impact water availability for all sectors (agriculture, energy, municipal, industry) and lead to critical shortages. WARMF-ZeroNet, as part of the integrated ZeroNet decision support system, offers stakeholders an integrated approach to long-term water management that balances competing needs of existing water users and economic growth under the constraints of limited supply and potential climate change.
Corrosion of carbon steel in the stagnant cooling water
International Nuclear Information System (INIS)
In the cooling water system treated with zinc-polyphosphate inhibitor, the relationship between inhibitor performance and corroded conditions of heat exchangers was studied. When cooling water system was kept in wet lay-up state, inhibitor concentration in the water jucket of heat exchangers decreased 15 ? 30 percent per week, and turbidity increased 30 ? 150 percent per week. These results show that corrosion rate of shell-plate in stagnant cooling water is more rapid than in flowing cooling water. Applied trouble discrimination method based on SiO2 ratio to the chemical composition of corrosion products, corrosion trouble was observed in shell-plates of heat exchangers. When cooling water system is kept in wet lay-up state, cooling water in the water jucket of heat exchangers is isolated for mouter system. In this perfectly closed system, zinc-polyphosphate inhibitor was not effective for protection of corrosion of carbon steel, and metal (carbon steel) dissolution occurred. However, in the perfectly closed system, since the dissolved oxygen content of the system was reduced with lapse of time, reduction process at cathodic region was stopped, so corrosion of metals seemed to be inhibited. (author)
Emergency core cooling system for a pressurized water reactor
International Nuclear Information System (INIS)
The invention relates to an emergency core cooling system for a pressurized water reactor with at least two primary circuit piping and is aimed at the prevention of a brittle failure of the reactor pressure vessel during emergency core cooling if the reactor vessel is embrittled due to neutron irradiation after a longer operating time. This is achieved by auxiliary heating of the coolant
Evaluation of cooling water treatment programme at RAPS-3 and 4 with reference to chlorination and microbial control
International Nuclear Information System (INIS)
Water from Rana Pratap Sagar Lake is used in Rajasthan Atomic Power Station (RAPS) units 3 and 4 for cooling the condenser system. As the lake water is rich in nutrients and microflora, investigations were carried out on the nutrient quality, microflora distribution and chlorine decay to evaluate the cooling water treatment programme. Algal growth in emergency storage makeup water pools, weed growth on the cooling tower decks and biofilm growth on various materials (carbon steel, stainless steel, admiralty brass and cupronickel) were studied with an objective to understand the reasons for corrosion and failure of fire water pipeline. Visual examination showed that the emergency makeup water pools were infested with green algae and cyano-bacterial mats. Some algal growth was observed on induced draft cooling tower-3 structures. The bacterial counts in various water samples were low, except in emergency makeup water pool. Sulphate reducing bacteria (SRB) were present in makeup and demineralised waters. Chlorophyll pigment analysis showed that the makeup and emergency storage water pool had abundant algal growth. To prevent biofouling, chlorine is dosed at the rate of 7 kg/hr for 10 minutes; free residual oxidant (FRO) and chlorine decay were monitored at regular intervals. After 24 hrs, biofilm thickness on different materials ranged from 27-45 ?m. However, the thickness was reduced by 50 % after exposure to 2 ppm of chlorine for 15 minutes. In further investigations, r 15 minutes. In further investigations, it was found that the anion resin beads of demineraliser plant were infested with filamentous microbes. Hence, It is recommended to treat the feed water of DM plant. Tubercles were observed inside the failed fire water carbon steel pipeline and on removing the tubercles concentric ring patterns, typical signatures of SRB corrosion were observed. For controlling the biofouling problem in the cooling water system, it is recommended to maintain a chlorine dose of 2.3 ppm (which gives 0.8 ppm FRO) for two hours in every shift. To control the algal growth in the emergency storage water pools, it is recommended to dose 4.0 ppm of sodium hypochlorite on alternate days. (author)
The influence of Savannah River discharge and changing SRS cooling water requirements on the potential entrainment of ichthyoplankton at the SRS Savannah River intakes
International Nuclear Information System (INIS)
Entrainment (i.e., withdrawal of fish larvae and eggs in cooling water) at the SRS Savannah River intakes is greatest when periods of high river water usage coincide with low river dischargeduring the spawning season. American shad and striped bass are the two species of greatest concern because of their recreational and/or commercial importance and because they produce drifting eggs and larvae vulnerable to entrainment. In the mid-reaches of the Savannah River, American shad and striped bass spawn primarily during April and May. An analysis of Savannah River discharge during April and May 1973--1989 indicated the potential for entrainment of 4--18% of the American shad and striped bass larvae and eggs that drifted past the SRS. This analysis assumed the concurrent operation of L-, K-, and P-Reactors. Additional scenarios investigated were: (1) shutting down L- and P-Reactors, and operating K-Reactor with a recycle cooling tower; and (2) shutting down L- and P-Reactors, eliminating minimum flows to Steel Creek, and operating K-Reactor with a recycle cooling tower. The former scenario reduced potential entrainment to 0.7--3.3%, and the latter scenario reduced potential entrainment to 0.20.8%. Thus, the currently favored scenario of operating K-Reactor with a cooling tower and not operating L- and P-Reactors represents a significant lessening of the impact of SRS operations
Supercritical water-cooled reactor (SCWR) development through GIF collaboration
International Nuclear Information System (INIS)
The Generation IV International Forum (GIF) was established to conduct collaborative R and D that will lead to the development of the fourth generation of advanced reactor systems. Six reactor concepts were selected for further development through GIF collaboration: 1) Very- High-Temperature Reactor (VHTR), 2) Sodium-cooled Fast Reactor (SFR), 3) Super-Critical Water-cooled Reactor (SCWR), 4) Gas-cooled Fast Reactor (GFR), 5) Lead-cooled Fast Reactor (LFR), and 6) Molten Salt Reactor (MSR). This paper presents the major features of the SCWR conceptual designs under consideration by the GIF SCWR members as well as relevant ongoing and planned R and D efforts
Supplementary report: cooling water systems for Darlington G.S
International Nuclear Information System (INIS)
This report summarizes Ontario Hydro's existing aquatic environmental programs, presents results of these investigations, and outlines plans and activities for expanded aquatic environment studies including the evaluation of alternative cooling systems. This report outlines specific considerations regarding possible alternative cooling arrangements for the Darlington station. It concludes with a recommendation that a study be initiated to examine the potential benefits of using the heated discharge water in a warm water recreational centre. (author)
Heat transfer during cooling of hot surfaces by water nozzles
P�i?hoda, M.; Moli?nek, J.; Pyszko, R.; Velic?ka, M.; Vaculi?k, M.; Burda, J.
Method of cooling in a secondary zone of continuous casting of steel has a significant influence on a quality of continuously cast products mainly from the point of view of internal and surface defects as well as zonal segregations. At the department of thermal engineering, a physical model of the secondary zone has been developed, which enables testing of both water and water-air nozzles. During laboratory measurements cooling effects of a cone nozzle have been expressed by means of three pa...
Passive containment cooling for an advanced small pressurized water reactor
International Nuclear Information System (INIS)
Containment cooling using natural convection and radiation was a key passive safety feature studied for a 600 MWe advance small pressurized water reactor (ASPWR). A free standing cylindrical steel containment vessel is surrounded by a reinforced concrete shield building configured as a chimney. To enhance natural convection cooling, the following were evaluated: water sprays, heat pipes, convection from the dome in addition to the cylinder, vertical fins, vertical corrugations, larger containment, and reboilers inside paired with air cooled condensers outside. Results of this evaluation are presented
Water mist effect on cooling process and microstructure of silumin
Directory of Open Access Journals (Sweden)
R. W?adysiak
Full Text Available The paper presents the results of the process of crystallization and cooling of the AlSi11 silumin and temperature distribution in the wall of iron and bronze research casting die in the temperature field of 750 to 100�C in casting of the silumin with use of water cooling mist in the air at a pressure of 0.30 to 0.40MPa and the water from 0.35 to 0.45MPa. Showing the nature and rate of change of temperature in die casting and the formation of temperature gradient on the thickness of the die casting wall in the direction of the nozzle surface of the outer wall of the cooling die casting. Using derivation curves and regression equations there has been compared: the mean and instantaneous rates of crystallization and cooling cast in values of 750 � 200�C. In addition, there are presented the differences arising from the microstructure change of the die�s type and thickness of its walls, the thickness of cast and the fact of using cooling water mist. The conduct of the changes of the hardness of the cast as a result of the applied cooling method of the die casting. It has been shown that the use of water mist with a variability of the die�s wall thickness in the cooling zone gives control of the crystallization process, microstructure and mechanical properties of the final silumin cast.
The impact of uncertainty in climate change scenarios on projections of future water supply from the Asian water towers
Immerzeel, W. W.; Pellicciotti, F.; Gobiet, A.; Ragettli, S.
The water towers of Asia, referred to also as the Third Pole for their importance in terms of cryospheric processes and magnitude of water resources from snow and ice, provide water resources to sustain the lives of nearly two billion people and the source of water for ten major river basins. Assessment of future changes in the water resources from this area is crucial because of the importance of these water sources for population needs and because of the already existing pressure on water availability and increasing water scarcity. Quantifying the response of such catchments to current and future changes in climate is complicated by two main factors: i) the scarcity of ground data, especially those on the cryosphere, which hinders both proper understanding of processes and calibration of models; ii) difficulty in capturing the large variability in climate over short horizontal distances. In addition most predictions of changes in water resources in the region are based on a few GCM scenarios used to force hydrological models. Given the complexity of the climatic mechanisms in the region, and of the monsoon in particular, it is essential that impact studies examine the entire range of expected changes in future climate scenarios. In this study we therefore examine the full range of CMIP3 GCMs to assess the robustness of projected trends in precipitation, air temperature and other variables relevant for cryospheric processes. We do this analysis for the upstream(defined as all area higher than 2000 meter), and downstream areas of the 10 large river basins in Asia that originate in the Himalayas, adjacent mountain ranges and the Tibetan plateau. Secondly, we investigate how this uncertainty in GCM projections translates into the hydrological response of the Hunza catchment in the Karakoram mountains in Pakistan. A physically-based and distributed hydrological model is set-up and calibrated based on observed discharges and MODIS snow cover maps and subsequently forced with the full range of (downscaled) CMIP3 GCMs. Downscaling is carried out using a stochastic approach that permits to establish a range of statistically probable future scenarios and provides information about the local uncertainty in the final result. In this way, we quantify uncertainty in discharge, stream flow composition, glacier evolution and snow cover which is associated with both the range of future GCMs predictions and downscaling technique. Results show that forcing hydrological impact models with only a selection of GCMS can lead to misleading predictions of changes in water resources, and errors can be as large as those associated with the uncertainty in model parameters.
Investigation of statistical behavior of nuclear power plant reinforced concrete cooling tower shell due to randomness in material and geometrical parameters using simulation approach
International Nuclear Information System (INIS)
In this paper, the response variability of reinforced concrete cooling tower shell due to randomness in material and geometrical parameters is investigated based on the simulation approach by using Monte Carlo simulation. Contrary to the ideal assumption on the shape imperfection such as the axisymmetric cosine shape and/or the cyclic shape imperfections we assume the shape imperfection due to randomness in the geometrical parameters as stochastic field and consider also the material randomness in the elastic modulus of concrete. By assuming correlation between these random parameters, the effect of randomness of these parameters on the response variability is investigated. Based on the analysis on the numerical results, a detailed investigation on the statistical response is given. In particular, the effect of correlation on the response variability in between the random parameters is addressed with which the analysis and design procedures of this structure can be improved. (authors)
Water cooling system for sintering furnaces of nuclear fuel pellets
International Nuclear Information System (INIS)
This work has as a main objective to develop a continuous cooling water system, which is necessary for the cooling of the sintering furnaces. This system is used to protect them as well as for reducing the water consumption, ejecting the heat generated into this furnaces and scattering it into the atmosphere in a fast and continuous way. The problem was defined and the reference parameters established, making the adequate research. The materials were selected as well as the length of the pipeline which will carry the secondary refrigerant fluid (water). Three possible solutions were tried,and evaluated, and from these, the thermal and economically most efficient option was selected. The layout of the solution was established and the theoretical construction of a cooling system for liquids using dichlorofluoromethane (R-22), as a refrigerant and a air cooled condenser, was accomplished. (Author)
Cooling water conditioning and quality control for tokamaks
International Nuclear Information System (INIS)
Designers and operators of Tokamaks and all associated water cooled, peripheral equipment, are faced with the task of providing and maintaining closed-loop, low conductivity, low impurity, cooling water systems. Most of these systems must provide large volumes of high quality cooling water at reasonable cost and comply with local and state government orders and EPA mandated national pretreatment standards and regulations. This paper discusses the DIII-D water quality requirements, the means used to obtain the necessary quality and the instrumentation used for control and monitoring. Costs to mechanically and chemically condition and maintain water quality are discussed as well as the various aspects of complying with government standards and regulations
DUSEL Facility Cooling Water Scaling Issues
Energy Technology Data Exchange (ETDEWEB)
Daily, W D
Precipitation (crystal growth) in supersaturated solutions is governed by both kenetic and thermodynamic processes. This is an important and evolving field of research, especially for the petroleum industry. There are several types of precipitates including sulfate compounds (ie. barium sulfate) and calcium compounds (ie. calcium carbonate). The chemical makeup of the mine water has relatively large concentrations of sulfate as compared to calcium, so we may expect that sulfate type reactions. The kinetics of calcium sulfate dihydrate (CaSO4 {center_dot} 2H20, gypsum) scale formation on heat exchanger surfaces from aqueous solutions has been studied by a highly reproducible technique. It has been found that gypsum scale formation takes place directly on the surface of the heat exchanger without any bulk or spontaneous precipitation in the reaction cell. The kinetic data also indicate that the rate of scale formation is a function of surface area and the metallurgy of the heat exchanger. As we don't have detailed information about the heat exchanger, we can only infer that this will be an issue for us. Supersaturations of various compounds are affected differently by temperature, pressure and pH. Pressure has only a slight affect on the solubility, whereas temperature is a much more sensitive parameter (Figure 1). The affect of temperature is reversed for calcium carbonate and barium sulfate solubilities. As temperature increases, barium sulfate solubility concentrations increase and scaling decreases. For calcium carbonate, the scaling tendencies increase with increasing temperature. This is all relative, as the temperatures and pressures of the referenced experiments range from 122 to 356 F. Their pressures range from 200 to 4000 psi. Because the cooling water system isn't likely to see pressures above 200 psi, it's unclear if this pressure/scaling relationship will be significant or even apparent. The most common scale minerals found in the oilfield include calcium carbonates (CaCO3, mainly calcite) and alkaline-earth metal sulfates (barite BaSO4, celestite SrSO4, anhydrite CaSO4, hemihydrate CaSO4 1/2H2O, and gypsum CaSO4 2H2O or calcium sulfate). The cause of scaling can be difficult to identify in real oil and gas wells. However, pressure and temperature changes during the flow of fluids are primary reasons for the formation of carbonate scales, because the escape of CO2 and/or H2S gases out of the brine solution, as pressure is lowered, tends to elevate the pH of the brine and result in super-saturation with respect to carbonates. Concerning sulfate scales, the common cause is commingling of different sources of brines either due to breakthrough of injected incompatible waters or mixing of two different brines from different zones of the reservoir formation. A decrease in temperature tends to cause barite to precipitate, opposite of calcite. In addition, pressure drops tend to cause all scale minerals to precipitate due to the pressure dependence of the solubility product. And we can expect that there will be a pressure drop across the heat exchanger. Weather or not this will be offset by the rise in pressure remains to be seen. It's typically left to field testing to prove out. Progress has been made toward the control and treatment of the scale deposits, although most of the reaction mechanisms are still not well understood. Often the most efficient and economic treatment for scale formation is to apply threshold chemical inhibitors. Threshold scale inhibitors are like catalysts and have inhibition efficiency at very low concentrations (commonly less than a few mg/L), far below the stoichiometric concentrations of the crystal lattice ions in solution. There are many chemical classes of inhibitors and even more brands on the market. Based on the water chemistry it is anticipated that there is a high likelihood for sulfate compound precipitation and scaling. This may be dependent on the temperature and pressure, which vary throughout the system. Therefore, various types and amounts of scaling ma
Auxiliary equipment for cooling water in a reactor
International Nuclear Information System (INIS)
Object: To effectively make use of pressure energy of reactor water, which has heretofore been discarded, to enable supply of emergency power supply of high reliability and to prevent spreading of environmental contamination. Structure: Sea water pumped by a sea water supply pump is fed to a heat exchanger. Reactor water carried through piping on the side to be cooled is removed in heat by the heat exchanger to be cooled and returned, and then again returned to the reactor. On the other hand, sea water heated by the heat exchanger is fed to a water wheel to drive the water wheel, after which it is discharged into a discharging path. A generator may be directly connected to the water wheel to use the electricity generated by the generator as the emergency power source. (Kamimura, M.)
Experiences on condenser cooling water treatment programme at NAPS
International Nuclear Information System (INIS)
The Narora Atomic Power Station has twin units of 220 MWe pressurized heavy water reactors, situated at the banks of river Ganges in Bulandshahr District of Uttar Pradesh. The plant cooling water takes the make up water supply from river Ganges after pretreatment using polyelectrolyte at two number of clariflocculators. The condenser cooling water system of the station is of open recirculating type and the clarified raw water used as a cooling medium is having a concentration cycle of cooling about 2.0. The calcium concentration in recirculating water is around 160 mg/litre as CaCO3 at full power of the unit. The Langelier Saturation Index of the recirculating water is observed to be in the range + 1.2 to + 1.8, indicating moderately high tendency, towards scale formation on heat transfer surfaces, such as condenser tubes, Turbine lubricating oil coolers and other associated heat exchangers. The condenser cooling water treatment was not envisaged in the original design. Therefore untreated surface water resulting in scale formation (0.3 to 0.5 mm thickness) due to deposition of calcium carbonate was observed in the condenser tubes of NAPS Unit 1 and 2 during initial period of operation (1989 to 1992). It was observed that the scaling on condenser tube surfaces caused increase in terminal temperature difference (TTD) from a design value of 5.5 degC to 13.0 degC. In addition to this a substantial drop in heat transfer coefficient from a value of about 2000 kc coefficient from a value of about 2000 kcal/hr/m2/degC to 1200 kcal/hr/m2/degC occurred. On thorough review actions were initiated at NAPS to restore the heat transfer through condensers. The present paper highlights the experiences on the treatment of cooling water
Use of reclaimed water for power plant cooling.
Energy Technology Data Exchange (ETDEWEB)
Veil, J. A.; Environmental Science Division
Freshwater demands are steadily increasing throughout the United States. As its population increases, more water is needed for domestic use (drinking, cooking, cleaning, etc.) and to supply power and food. In arid parts of the country, existing freshwater supplies are not able to meet the increasing demands for water. New water users are often forced to look to alternative sources of water to meet their needs. Over the past few years, utilities in many locations, including parts of the country not traditionally water-poor (e.g., Georgia, Maryland, Massachusetts, New York, and North Carolina) have needed to reevaluate the availability of water to meet their cooling needs. This trend will only become more extreme with time. Other trends are likely to increase pressure on freshwater supplies, too. For example, as populations increase, they will require more food. This in turn will likely increase demands for water by the agricultural sector. Another example is the recent increased interest in producing biofuels. Additional water will be required to grow more crops to serve as the raw materials for biofuels and to process the raw materials into biofuels. This report provides information about an opportunity to reuse an abundant water source -- treated municipal wastewater, also known as 'reclaimed water' -- for cooling and process water in electric generating facilities. The report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL) Innovations for Existing Plants research program (Feeley 2005). This program initiated an energy-water research effort in 2003 that includes the availability and use of 'nontraditional sources' of water for use at power plants. This report represents a unique reference for information on the use of reclaimed water for power plant cooling. In particular, the database of reclaimed water user facilities described in Chapter 2 is the first comprehensive national effort to identify and catalog those plants that are using reclaimed water for cooling.
Cooling systems for new-generation units
International Nuclear Information System (INIS)
Three coolant circuits of the new-generation unit are described, viz., 1. the main coolant circuit for cooling the condensers and steam turbine auxiliary equipment; 2. cooling technological water circuit of the major consuming equipment; 3. cooling technological water circuit of important consuming equipment of the primary part. Of the two variants considered for the coolant piping between the main generation unit and the cooling tower, that involving a reinforced concrete tube with a steel sealing insert is the more economical one. For the new units, one cooling tower is assigned to each unit. The cooling technological water circuit of the major consuming equipment of the primary part remains virtually unchanged, identical with that of the Temelin units. The entire cooling technological water circuit of important consuming equipment of the primary part is designed as earthquake and pressure wave resistant. In the unit, the safety systems are so designed that the number of subsystems is reduced as compared with the existing WWER type reactors, viz., from 3 x 100% to 2 x 100%, while the reliability of components (in terms of failure rate) is required to be as high as with the 3x 100% design of the Temelin nuclear power plant. As regards the cooling system, the new unit is designed in three variants: cooling by means of tanks with spraying, by means of fan-type cooling towers, and by means of microtowers with an emergency makeup water reservoir for each system. (Z.S.) water reservoir for each system. (Z.S.)
WRI 50: Strategies for Cooling Electric Generating Facilities Utilizing Mine Water
Energy Technology Data Exchange (ETDEWEB)
Joseph J. Donovan; Brenden Duffy; Bruce R. Leavitt; James Stiles; Tamara Vandivort; Paul Ziemkiewicz
Power generation and water consumption are inextricably linked. Because of this relationship DOE/NETL has funded a competitive research and development initiative to address this relationship. This report is part of that initiative and is in response to DOE/NETL solicitation DE-PS26-03NT41719-0. Thermal electric power generation requires large volumes of water to cool spent steam at the end of the turbine cycle. The required volumes are such that new plant siting is increasingly dependent on the availability of cooling circuit water. Even in the eastern U.S., large rivers such as the Monongahela may no longer be able to support additional, large power stations due to subscription of flow to existing plants, industrial, municipal and navigational requirements. Earlier studies conducted by West Virginia University (WV 132, WV 173 phase I, WV 173 Phase II, WV 173 Phase III, and WV 173 Phase IV in review) have identified that a large potential water resource resides in flooded, abandoned coal mines in the Pittsburgh Coal Basin, and likely elsewhere in the region and nation. This study evaluates the technical and economic potential of the Pittsburgh Coal Basin water source to supply new power plants with cooling water. Two approaches for supplying new power plants were evaluated. Type A employs mine water in conventional, evaporative cooling towers. Type B utilizes earth-coupled cooling with flooded underground mines as the principal heat sink for the power plant reject heat load. Existing mine discharges in the Pittsburgh Coal Basin were evaluated for flow and water quality. Based on this analysis, eight sites were identified where mine water could supply cooling water to a power plant. Three of these sites were employed for pre-engineering design and cost analysis of a Type A water supply system, including mine water collection, treatment, and delivery. This method was also applied to a ''base case'' river-source power plant, for comparison. Mine-water system cost estimates were then compared to the base-case river source estimate. We found that the use of net-alkaline mine water would under current economic conditions be competitive with a river-source in a comparable-size water cooling system. On the other hand, utilization of net acidic water would be higher in operating cost than the river system by 12 percent. This does not account for any environmental benefits that would accrue due to the treatment of acid mine drainage, in many locations an existing public liability. We also found it likely that widespread adoption of mine-water utilization for power plant cooling will require resolution of potential liability and mine-water ownership issues. In summary, Type A mine-water utilization for power plant cooling is considered a strong option for meeting water needs of new plant in selected areas. Analysis of the thermal and water handling requirements for a 600 megawatt power plant indicated that Type B earth coupled cooling would not be feasible for a power plant of this size. It was determined that Type B cooling would be possible, under the right conditions, for power plants of 200 megawatts or less. Based on this finding the feasibility of a 200 megawatt facility was evaluated. A series of mines were identified where a Type B earth-coupled 200 megawatt power plant cooling system might be feasible. Two water handling scenarios were designed to distribute heated power-plant water throughout the mines. Costs were developed for two different pumping scenarios employing a once-through power-plant cooling circuit. Thermal and groundwater flow simulation models were used to simulate the effect of hot water injection into the mine under both pumping strategies and to calculate the return-water temperature over the design life of a plant. Based on these models, staged increases in required mine-water pumping rates are projected to be part of the design, due to gradual heating and loss of heat-sink efficiency of the rock sequence above the mines. Utilizing pumping strategy No.1 (two mines) capital costs wer
Controlled Cooling of Hot Rolled Steel Channels by Water Spraying on the Final Cooling Bed
Directory of Open Access Journals (Sweden)
Srinivas Rachamadagu
Full Text Available The objective of this research is to design an effective and relatively simple method for controlled cooling of hot rolled steel channels by water spraying on the final cooling bed after continuous cast steel billets passing through reheating furnace and sequential rolls to form channels. The need for this research arose as the channels were being cooled by forced air draft and natural convection which brought the temperature of the channels to about 270�C (518�F at the shear stand. Steel at this temperature is too hot for convenient handling by the operators. Additional cooling by water spraying would be an acceptable solution but such cooling should be designed to enable an acceptable microstructure to be developed in the channel, as the microstructure of steel is strongly affected by nonequilibrium cooling through the eutectoid range: the mechanical properties of steel are a consequence of the microstructure. The approach followed in this investigation was first to develop a finite element method (FEM to determine the temperature profiles in the channel subjected to cooling by water spraying and natural convection and arrive at suitable water spray rates to bring the temperature of the channel at the shear stand to levels suitable for convenient handling. PATRAN was used for preprocessing and ABAQUS for processing and post processing. Next, laboratory experiments were conducted to determine the microstructure and hardness of channels at the spray rates found suitable through FEM, to suggest the water spray rate most suitable for providing a temperature convenient for handling and for developing a desirable microstructure.
Water-cooled insulated steam-injection wells
Back, L. H.; Jaffe, L. D.
Water is used as insulated coolant and heat-transfer medium for steam-injection oil wells. Approach is somewhat analogous to cooling system in liquid-propellant rocket. In addition to trapping and delivering heat to steam-injection point, water will also keep casing cooler, preventing or reducing casing failures caused by thermal stresses.
Open air-vapor compression refrigeration system for air conditioning and hot water cooled by cool water
International Nuclear Information System (INIS)
This paper presents an open air-vapor compression refrigeration system for air conditioning and hot water cooled by cool water and proves its feasibility through performance simulation. Pinch technology is used in analysis of heat exchange in the surface heat exchanger, and the temperature difference at the pinch point is selected as 6 oC. Its refrigeration depends mainly on both air and vapor, more efficient than a conventional air cycle, and the use of turbo-machinery makes this possible. This system could use the cool in the cool water, which could not be used to cool air directly. Also, the heat rejected from this system could be used to heat cool water to 33-40 oC. The sensitivity analysis of COP to ? c and ? t and the simulated results T 4, T 7, T 8, q 1, q 2 and W m of the cycle are given. The simulations show that the COP of this system depends mainly on T 7, ? c and ? t and varies with T 3 or T wet and that this cycle is feasible in some regions, although the COP is sensitive to the efficiencies of the axial compressor and turbine. The optimum pressure ratio in this system could be lower, and this results in a fewer number of stages of the axial compressor. Adjusting the rotation speed of the axial compressor can easily control the pressure ratio, mass flow rate and the refrigerating capacity.w rate and the refrigerating capacity. The adoption of this cycle will make the air conditioned room more comfortable and reduce the initial investment cost because of the obtained very low temperature air. Humid air is a perfect working fluid for central air conditioning and no cost to the user. The system is more efficient because of using cool water to cool the air before the turbine. In addition, pinch technology is a good method to analyze the wet air heat exchange with water
Assessment of effectiveness of water mist cooling of casting die
Directory of Open Access Journals (Sweden)
R. W?adysiak
Full Text Available At work research findings of the process of cooling the research casting die in the range of the 600-100�C temperature were presented and of the research-production casting die while pouring the cycle out cooled with compressed air about the pressure 0.6 MPa and the water mist about the pressure of air and water appropriately 0.3/0.35 MPa. The character and the speed of the temperature changes in the die and being formed of gradient of the temperature on the thickness partition walls were shown the die with the help of thermal and derivative curves. A course of changes was presented to the density of the thermal stream during cooling and in function of the temperature as well as results were shown a computer simulation of the process of pouring the production casting die. A scheme of the device for generating the water mist cooling the die and an image of spraying water were shown with the help of the designed rotary sprayer. They showed that applying the water mist for cooling dies is increasing the intensity of casting process and is accelerating it.
Effect of Oxidizing Bioxides to the Microorganism Growth at RSG-GAS Secondary Cooling Water
International Nuclear Information System (INIS)
The RSG-GAS secondary cooling system is open recirculation cooling water. One of the problem at the recirculation open cooling water system is the microorganism growth. To control of the microorganism growth at RSG-GAS secondary cooling system carried out by addition oxidizing biocides chemical and monitoring of the microorganism growth in secondary cooling water. Monitoring of the microorganism growth carried out by determine total count of bacteria in secondary cooling water system with Dipslides Test. From the monitoring result showed that at the secondary cooling system shutdown was the microorganism growth at secondary cooling water system growth faster and than decrease growth after addition of the oxidizing biocides. (author)
Cooling rate, heating rate and aging effects in glassy water
Giovambattista, Nicolas; Stanley, H. Eugene; Sciortino, Francesco
We report a molecular dynamics simulation study of the properties of the potential energy landscape sampled by a system of water molecules during the process of generating a glass by cooling, and during the process of regenerating the equilibrium liquid by heating the glass. We study the dependence of these processes on the cooling/heating rates as well as on the role of aging (the time elapsed in the glass state). We compare the properties of the potential energy landscape ...
Cooling of concrete structure in advanced heavy water reactor
International Nuclear Information System (INIS)
Innovative nuclear power plants are being designed by incorporation of passive systems to the extent possible for enhancing the safety by elimination of active components. BARC has designed Advanced Heavy Water Reactor (AHWR) incorporating several passive systems to facilitate the fulfillment of safety functions of the reactor during normal operation, residual heat removal, emergency core cooling, confinement of radioactivity etc. In addition to these passive systems, an innovative passive technology is being developed to protect, the concrete structure in high temperature zone (V1-volume). Passive Concrete Cooling System (PConCS) uses the principle of natural circulation to provide cooling outside the insulation cabinet encompassing high temperature piping. Cooling water is circulated from overhead GDWP in cooling pipes fixed over corrugated plate on outer surface of insulation cabinet and maintains low temperature of concrete structure. Modular construction of insulation cabinet and cooling pipes external to the concrete surface simplifies the design, construction and refurbishment if required. The paper describes the details of passive technology for concrete cooling. (author)
Analyses of a supercritical water cooled pressurized water reactor
International Nuclear Information System (INIS)
A Supercritical Water Cooled Pressurized Water Reactor (SDWR) has been investigated in terms of technical feasibility, efficiency and economic features. In this context the main focus of this work is on the development of suitable methods for the different analysis steps. The SDWR reactor concept includes a primary coolant loop with water under supercritical pressure conditions (system pressure 25 MPa) and a heat up in the reactor core from 280 C up to 380 C. Due to these relatively high thermodynamic: conditions the SDWR provides considerable advantages in the area of efficiency and economy compared to conventional pressurized water reactors. Additionally the physics of the supercritical water (single phase flow) shall result in favourable safety features because unwanted two-phase flow phenomena like DNB and Dry-Out are excluded. On the other hand the high heat up of the coolant leads to a rather large coolant density change between the inlet and the outlet of the core. This requires the use of a complicated fuel assembly design with separated channels for the counter current flow of coolant and moderator in the reactor core. This complicated design and the strong property change of the supercritical water in the core give rise to the development of an new coupled thermal hydraulic - neutronic core calculation method. Therefore the neutronic code MCNP5 and a modified version of the thermal hydraulics code STAFAS have been coupled and successfully applied on the reacupled and successfully applied on the reactor core of the SDWR. As a result characteristic data like the distribution of power, temperature and coolant mass flow in the core has been evaluated assembly wise. Additionally the hottest fuel assembly in the core has been determined for a subsequent sub channel analyses which provides a more detailed spatial resolution. This allows the determination of local safety-relevant data e.g. fuel, cladding and coolant temperatures. Furthermore this work includes the implementation of a new method for the interpolation of the detailed pin wise power distribution from the rather coarse core calculations which is need as an input for the sub channel analyses. In the sub channel approach a volumeaveraged set of transport equations is solved. Thus, local thermal hydraulic: phenomena which occur within the averaging volume (e.g. pressure loss due to friction, fluid mixing due to turbulence) have to be considered by additional models. In general such models are strongly dependant on the flow case and do not exist for the given fluid properties and the complicated sub channel geometry. For this reason extensive CFD calculations (RANS / URANS) of the coolant flow in rod bundles have been done with the commercial program Star-CD. The CFD results have been validated against experimental correlations and suitable models for the sub channel approach have been evaluated. (orig.)
Evaluation of water quality in case of using pond water as supply water of secondary cooling system in HANARO
International Nuclear Information System (INIS)
There is about 80 m3/h loss of the secondary cooling water by evaporation, windage and blowdown during the operation of HANARO, 30 MW research reactor. To reduce the cost to maintain the water quality of secondary cooling system, we have added the filtering system for the circulation water of secondary cooling system and applied high Ca-hardness treatment program instead of low Ca-hardness to minimized blowdown. But, we intend to more reduce the cost maintaining the water quality treatment, water supply system has been added to use the pond water, around HANARO, as supply water of the secondary cooling system. In this paper, the main factors for waster quality treatment were evaluated to confirm whether it is applicable to use the pond water as the supply water of secondary cooling water. As results, it was confirmed that high Ca-hardness treatment program is safely maintained through the evaluation
Electricity prices, river temperatures and cooling water scarcity
McDermott, Grant; Nilsen, �ivind Anti
Thermal-based power stations rely on water for cooling purposes. These water sources may be subject to incidents of scarcity, environmental regulations and competing economic concerns. This paper analyses the effect of water scarcity and increased river temperatures on German electricity prices from 2002 to 2009. Having controlled for demand effects, the results indicate that the electricity price is significantly impacted by both a change in river temperatures and the relative abundance of r...
Assessment of effectiveness of water mist cooling of casting die
At work research findings of the process of cooling the research casting die in the range of the 600-100�C temperature were presented and of the research-production casting die while pouring the cycle out cooled with compressed air about the pressure 0.6 MPa and the water mist about the pressure of air and water appropriately 0.3/0.35 MPa. The character and the speed of the temperature changes in the die and being formed of gradient of the temperature on the thickness partition walls were sho...
Water mist effect on cooling process and microstructure of silumin
The paper presents the results of the process of crystallization and cooling of the AlSi11 silumin and temperature distribution in the wall of iron and bronze research casting die in the temperature field of 750 to 100�C in casting of the silumin with use of water cooling mist in the air at a pressure of 0.30 to 0.40MPa and the water from 0.35 to 0.45MPa. Showing the nature and rate of change of temperature in die casting and the formation of temperature gradient on the thickness of the die c...
Potentials of heat recovery from 850C LEP cooling water
International Nuclear Information System (INIS)
Most of the cooling water from LEP has a too low temperature (30 to 400C) to be considered for economical recovery of energy. However, it is hoped that the heat from the klystrons be removed at a temperature of 850C and that this part of the LEP cooling water might be used for saving primary energy. In this study different possibilities have been investigated to make use of the waste heat for heating purposes during winter time, for saving energy in the refrigeration process in summer and for power generation. Cost estimates for these installations are also given and show their economic drawbacks. (orig.)
Low temperature heating and high temperature cooling embedded water based surface heating and cooling systems
Babiak, Jan; Petras, Dusan
This Guidebook describes the systems that use water as heat-carrier and when the heat exchange within the conditioned space is more than 50% radiant. Embedded systems insulated from the main building structure (floor, wall and ceiling) are used in all types of buildings and work with heat carriers at low temperatures for heating and relatively high temperature for cooling.
77 FR 36014 - Initial Test Program of Emergency Core Cooling Systems for Boiling-Water Reactors
...Core Cooling Systems for Boiling-Water Reactors AGENCY: Nuclear Regulatory Commission...Core Cooling Systems for Boiling- Water Reactors.'' This guide describes methods that...systems (ECCSs) for boiling-water reactors (BWRs). DATES: Submit comments...
78 FR 64027 - Preoperational Testing of Emergency Core Cooling Systems for Pressurized-Water Reactors
...Cooling Systems for Pressurized-Water Reactors AGENCY: Nuclear Regulatory Commission...Cooling Systems for Pressurized-Water Reactors.'' This RG is being revised to incorporate...preoperational testing of new pressurized water reactor (PWR) designs. ADDRESSES:...
Conditioning of cooling water in power stations. Feedback from twenty years of experience with acid feeding
Energy Technology Data Exchange (ETDEWEB)
Goffin, C.; Duvivier, L.; Girasa, E. [LABORELEC, Chemistry of Water (Belgium); Brognez, J. [ELECTRABEL, TIHANGE Nuclear Power Station (Belgium)
In the late 1970's and early 1980's, with the development of the nuclear programme in many European countries, the recirculation of cooling water in power stations became an issue which required urgent attention. The concentration of several plants of 1000 MW or more on sites along inland waterways actually made simple once-through cooling impossible, owing to the risk of an unacceptable rise in the river's water temperature. The chemical composition of natural freshwater in western European waterways is such that when it becomes slightly concentrated, scale is rapidly formed. The relatively low solubility of calcium carbonate and the degassing of the carbon dioxide during close contact between the water and air in the heat exchangers of the cooling tower explain this precipitation tendency. Fairly soon, experts in the electricity power generation companies highlighted the need for on-site, pilot loop simulations, in order to foresee the physico-chemical phenomena that could arise in industrial installations. The number of financially justifiable processing possibilities could be briefly summarised by the following three solutions: to adapt the concentration factor in order to be under the calcium carbonate solubility limit and thereby avoid the need for any water conditioning; to accept concentration factors of between 1.4 and 1.9 and control the calcium carbonate precipitation through controlled acid injection in the circulation water; to raise the concentration factor over 5 and soften the makeup water through the addition of lime and flocculant. The last of these solutions was rarely ever used in Belgium and France. It was however widely used in Germany. Its application requires a greater investment and leads to higher operating costs than acid injection. Furthermore, it leads to the problem of daily drying and disposal of several dozen tonnes of sludge, which have to be recycled or dumped. In an increasingly stringent environmental context, this solution is no longer easily justifiable. The research efforts undertaken to better understand and control calcium carbonate precipitation and scale formation have paid off and have resulted in the standardisation of the treatment process and the control procedure of the cooling circuits by ELECTRABEL. The initial experience gained in the fossil power plants of AMERCOEUR (2 x 125 MW units) was finally successfully applied to plants 2 and 3 at TIHANGE. Since then, all of the conventional or combined cycle power plants have adopted the same treatment philosophy. Six units of between 125 and 1000 MW have been treated in this manner, some of them for over twenty years, without showing any signs of scale deposits. It is true that adaptations have had to be made in the control recommendations defined during the pilot trials, in order to allow for the impact of cathodic protections and certain cooling tower fills. (authors)
Conditioning of cooling water in power stations. Feedback from twenty years of experience with acid feeding
International Nuclear Information System (INIS)
In the late 1970's and early 1980's, with the development of the nuclear programme in many European countries, the recirculation of cooling water in power stations became an issue which required urgent attention. The concentration of several plants of 1000 MW or more on sites along inland waterways actually made simple once-through cooling impossible, owing to the risk of an unacceptable rise in the river's water temperature. The chemical composition of natural freshwater in western European waterways is such that when it becomes slightly concentrated, scale is rapidly formed. The relatively low solubility of calcium carbonate and the degassing of the carbon dioxide during close contact between the water and air in the heat exchangers of the cooling tower explain this precipitation tendency. Fairly soon, experts in the electricity power generation companies highlighted the need for on-site, pilot loop simulations, in order to foresee the physico-chemical phenomena that could arise in industrial installations. The number of financially justifiable processing possibilities could be briefly summarised by the following three solutions: to adapt the concentration factor in order to be under the calcium carbonate solubility limit and thereby avoid the need for any water conditioning; to accept concentration factors of between 1.4 and 1.9 and control the calcium carbonate precipitation through controlled acid injection in the circulation water; to raise the concentration factor over 5 and soften the makeup water through the addition of lime and flocculant. The last of these solutions was rarely ever used in Belgium and France. It was however widely used in Germany. Its application requires a greater investment and leads to higher operating costs than acid injection. Furthermore, it leads to the problem of daily drying and disposal of several dozen tonnes of sludge, which have to be recycled or dumped. In an increasingly stringent environmental context, this solution is no longer easily justifiable. The research efforts undertaken to better understand and control calcium carbonate precipitation and scale formation have paid off and have resulted in the standardisation of the treatment process and the control procedure of the cooling circuits by ELECTRABEL. The initial experience gained in the fossil power plants of AMERCOEUR (2 x 125 MW units) was finally successfully applied to plants 2 and 3 at TIHANGE. Since then, all of the conventional or combined cycle power plants have adopted the same treatment philosophy. Six units of between 125 and 1000 MW have been treated in this manner, some of them for over twenty years, without showing any signs of scale deposits. It is true that adaptations have had to be made in the control recommendations defined during the pilot trials, in order to allow for the impact of cathodic protections and certain cooling tower fills. (authors)
Energy Technology Data Exchange (ETDEWEB)
V. King
The Pool Water Treatment and Cooling System is located in the Waste Handling Building (WHB), and is comprised of various process subsystems designed to support waste handling operations. This system maintains the pool water temperature within an acceptable range, maintains water quality standards that support remote underwater operations and prevent corrosion, detects leakage from the pool liner, provides the capability to remove debris from the pool, controls the pool water level, and helps limit radiological exposure to personnel. The pool structure and liner, pool lighting, and the fuel staging racks in the pool are not within the scope of the Pool Water Treatment and Cooling System. Pool water temperature control is accomplished by circulating the pool water through heat exchangers. Adequate circulation and mixing of the pool water is provided to prevent localized thermal hotspots in the pool. Treatment of the pool water is accomplished by a water treatment system that circulates the pool water through filters, and ion exchange units. These water treatment units remove radioactive and non-radioactive particulate and dissolved solids from the water, thereby providing the water clarity needed to conduct waste handling operations. The system also controls pool water chemistry to prevent advanced corrosion of the pool liner, pool components, and fuel assemblies. Removal of radioactivity from the pool water contributes to the project ALARA (as low as is reasonably achievable) goals. A leak detection system is provided to detect and alarm leaks through the pool liner. The pool level control system monitors the water level to ensure that the minimum water level required for adequate radiological shielding is maintained. Through interface with a demineralized water system, adequate makeup is provided to compensate for loss of water inventory through evaporation and waste handling operations. Interface with the Site Radiological Monitoring System provides continuous radiological monitoring of the pool water. The Pool Water Treatment and Cooling System interfaces with the Waste Handling Building System, Site-Generated Radiological Waste Handling System, Site Radiological Monitoring System, Waste Handling Building Electrical System, Site Water System, and the Monitored Geologic Repository Operations Monitoring and Control System.
Closed loop system lowers service water temperature
International Nuclear Information System (INIS)
This article describes, Gulf States Utilities completed conversion of the service water system at River Bend station to a treated demineralized water closed loop system. The modification to this 63,000-gpm system required separating service water from the larger circulating water cooling system that cools the main condenser. New service water pumps were installed along with eight parallel plate and frame heat exchangers. The heat exchangers transfer heat from the service water system to a new service water cooling system. The cooling system is composed of a 63,000-gpm five-cell mechanical draft cooling tower, three cooling tower pumps, and eight automatic pressure flush strainers. Motor-operated valves, piping, and controls are also provided that allow automatic operation. This includes heat exchanger backflushing, strainer flushing, and tower fan operation to control temperature
Water-cooled beam line components at LAMPF
International Nuclear Information System (INIS)
The beam line components that comprise the main experimental beam at the Clinton P. Anderson Meson Physics Facility (LAMPF) have been operating since February 1976. This paper will define the functions of the primary water-cooled elements, their design evolution, and our operating experience to the present time
Computational Simulation of a Water-Cooled Heat Pump
Bozarth, Duane
A Fortran-language computer program for simulating the operation of a water-cooled vapor-compression heat pump in any orientation with respect to gravity has been developed by modifying a prior general-purpose heat-pump design code used at Oak Ridge National Laboratory (ORNL).
SCWR Super-Critical Water-cooled Reactor
International Nuclear Information System (INIS)
The SCWR (Super-Critical Water-cooled Reactor) is a water-cooled reactor that operates above the thermodynamic critical point. Several design options using pressure vessel and pressure tube technologies are currently under consideration with the aim of providing a spectrum of possibilities for consideration for the next generation of water-cooled reactor technology. The collaborative GIF (Generation 4. International Forum) research projects focus on areas that are common to the design options under considerations by the SCWR members. Two major collaborative research projects are currently underway. First, materials and chemistry: this project involves testing of key materials for use both in-core and out-core, for both the pressure tube and pressure vessel designs. A reference water chemistry will also be investigated, based in large part on materials compatibility and the radiolysis behavior. Secondly, basic thermal-hydraulic phenomena, safety, stability and methods development: this project will address knowledge gaps that exist in key areas such as heat transfer and critical flow at supercritical conditions. The design-basis accidents for an SCWR will have some similarities with conventional water reactors, but the different thermalhydraulic behavior and large changes in properties around the critical point compared to water at lower temperatures and pressures will have to be better understood
Trihalomethanes in chlorinated cooling waters of nuclear reactors
International Nuclear Information System (INIS)
The Savannah River Plant (SRP) near Aiken, SC has three operating nuclear reactors and used approximately 100-300 kg/day of chlorine to combat reactor heat exchanger biofouling. SRP cooling water is high in organic carbon and following chlorination, the water is occasionally heated to temperatures exceeding 700 C as it passes through the heat exchangers, forming conditions conducive to the formation of trihalomethanes (THMs), which are known human carcinogens. This study was conducted to examine the production and persistence of THMs resulting from the chlorination and heating of SRP reactor cooling waters. The concentration of total THM in all water samples collected in and around the SRP site were less than 59?g/L, and there was no appreciable increase in the concentrations of THM in the Savannah River downstream of the SRP site. THM levels in all cases were below U.S. Environmental Protection Agency drinking water guidelines (100 ?g/L), and it was concluded that THM levels resulting from the chlorination of reactor cooling water at the SRP were insignificant
The effects of high-Ca hardness water treatment for secondary cooling water in HANARO
International Nuclear Information System (INIS)
Water-quality control of the second cooling system in HANARO has been altered from low Ca-hardness treatment to high Ca-hardness treatment since March, 2001. High Ca-hardness water treatment in HANARO is to maintain the calcium hardness around 12 by minimizing the blowdown of secondary cooling water. This paper describes the effect of cost reduction after change of water-quility treatment method. The result shows that the cost of the water could be reduced by 25% using the pond water in KAERI. The amount and cost for the chemical agent could be reduced by 40% and 10% respectively
Natural Circulation Phenomena and Modelling for Advanced Water Cooled Reactors
International Nuclear Information System (INIS)
The role of natural circulation in advanced water cooled reactor design has been extended with the adoption of passive safety systems. Some designs utilize natural circulation to remove core heat during normal operation. Most passive safety systems used in evolutionary and innovative water cooled reactor designs are driven by natural circulation. The use of passive systems based on natural circulation can eliminate the costs associated with the installation, maintenance and operation of active systems that require multiple pumps with independent and redundant electric power supplies. However, considering the weak driving forces of passive systems based on natural circulation, careful design and analysis methods must be employed to ensure that the systems perform their intended functions. Several IAEA Member States with advanced reactor development programmes are actively conducting investigations of natural circulation to support the development of advanced water cooled reactor designs with passive safety systems. To foster international collaboration on the enabling technology of passive systems that utilize natural circulation, in 2004 the IAEA initiated a coordinated research project (CRP) on Natural Circulation Phenomena, Modelling and Reliability of Passive Systems that Utilize Natural Circulation. Three reports were published within the framework of this CRP. The first report (IAEA-TECDOC-1474) contains the material developed for the first IAEA training course on natural circulation in water cooled nuclear power plants. The second report (IAEA-TECDOC-1624) describes passive safety systems in a wide range of advanced water cooled nuclear power plant designs, with the goal of gaining insights into system design, operation and reliability. This third, and last, report summarizes the research studies completed by participating institutes during the CRP period.
Procedure for operating a heavy water cooled power reactor
International Nuclear Information System (INIS)
Nuclear reactors cooled by heavy water usually have equipment for fuel element exchange during operation, with the primary circuit remaining contained. This fuel element exchange equipment is expensive and complicated in many respects. According to the invention, the heavy water is therefore replaced by light water after a certain time of operation in such way that light water is led in and heavy water is led off. After the replacement, at least a quarter of the fuel elements of the reactor core is exchanged with the reactor pressure vessel being open. Then the light water serving as a shielding is replaced by heavy water, with the reactor pressure vessel being closed. The invention is of interest particularly for high-conversion reactors. (orig.)
Methodologies for estimating air emissions from three non-traditional source categories: Oil spills, petroleum vessel loading and unloading, and cooling towers. Final report, October 1991-March 1993
International Nuclear Information System (INIS)
The report discusses part of EPA's program to identify and characterize emissions sources not currently accounted for by either the existing Aerometric Information Retrieval System (AIRS) or State Implementation Plan (SIP) area source methodologies and to develop appropriate emissions estimation methodologies and emission factors for a group of these source categories. Based on the results of the identification and characterization portions of this research, three source categories were selected for methodology and emission factor development: oil spills, petroleum vessel loading and unloading, and cooling towers. The report describes the category selection process and presents emissions estimation methodologies and emission factor data for the selected source categories. The discussions for each category include general background information, emissions generation activities, pollutants emitted, sources of activity and pollutant data, emissions estimation methodologies and data issues. The information used in these discussions was derived from various sources including available literature, industrial and trade association publications and contracts, experts on the category and activity, and knowledgeable federal and state personnel
Technology for Water Treatment
There are approximately 500,000 water cooling towers in the United States, all of which must be kept clear of "scale" and corrosion and free of pollutants and bacteria. Electron Pure, Ltd. manufactures a hydro cooling tower conditioner as well as an automatic pool sanitizer. The pool sanitizer consists of two copper/silver electrodes placed in a chamber mounted in the pool's recirculation system. The tower conditioner combines the ionization system with a water conditioner, pump, centrifugal solids separator and timer. The system saves water, eliminates algae and operates maintenance and chemical free. The company has over 100 distributors in the U.S. as well as others in 20 foreign countries. The buildup of scale and corrosion is the most costly maintenance problem in cooling tower operation. Jet Propulsion Laboratory successfully developed a non-chemical system that not only curbed scale and corrosion, but also offered advantages in water conservation, cost savings and the elimination of toxic chemical discharge. In the system, ozone is produced by an on-site generator and introduced to the cooling tower water. Organic impurities are oxidized, and the dissolved ozone removes bacteria and scale. National Water Management, a NASA licensee, has installed its ozone advantage systems at some 200 cooling towers. Customers have saved money and eliminated chemical storage and discharge.
Can rupture detector for water cooled piles
International Nuclear Information System (INIS)
The object of this study was to develop a simple, easy to-build, apparatus for showing the appearance of a defect on a fuel element can of a swimming pool reactor. The apparatus used consists of a coil of activated carbon around a NaI(Tl) crystal. Through this coil pass the gases obtained by degassing a sample of water from the reactor; the fission gases which appear when a can leaks are trapped in the carbon; the NaI(Tl) crystal is coupled with a photomultiplier followed by a single-channel selector fixed on a photo-electric peak characteristic of the ? spectrum of fission gases. Preliminary experiments were carried out in laboratory; a more complete device was then built and is now working in the reactor Melusine. (author)
Engineered safeguard systems for the prototype heavy water moderated, boiling light water cooled reactor 'FUGEN'
International Nuclear Information System (INIS)
The prototype heavy water-moderated, boiling light water-cooled reactor, or Advanced Thermal Reactor, ''FUGEN'' is different in many respects from conventional light water reactors because of its construction comprising multipressure-tube core. This report describes on the emergency core cooling system of FUGEN and the results of examining the adaptability to the new evaluation guide proposed for that of light water reactors. The emergency core cooling system of FUGEN is composed of 3 injection systems, each comprising two independent systems. The analysis code S are used to evaluate cooling water behaviour and the operation of emergency core cooling system, and have been improved or the unsettled parameters were determined, and the reliability was confirmed by the results of experiments. The basic concept of the ''new evaluation guide for emergency core cooling system of light water reactors'' is (1) requirement of exact backing data, (2) consideration of appropriate safety allowance for backing data, and (3) adoption and proof of more detailed physical model. The discussed results show that the max. temperature of cald tubes is 9900C even taking fuel deformation in consideration, and sufficiently lower than 12000C, the reference value indicated in the guide. Thus the core safety of FUGEN has been confirmed to be fully maintained with the present emergency core cooling system. (Wakatsuki, Y.)
Application of Pulsed Electrical Fields for Advanced Cooling and Water Recovery in Coal-Fired Power Plant
Energy Technology Data Exchange (ETDEWEB)
Young Cho; Alexander Fridman
The overall objective of the present work was to develop technologies to reduce freshwater consumption in a cooling tower of coal-based power plant so that one could significantly reduce the need of make-up water. The specific goal was to develop a scale prevention technology based an integrated system of physical water treatment (PWT) and a novel filtration method so that one could reduce the need for the water blowdown, which accounts approximately 30% of water loss in a cooling tower. The present study investigated if a pulsed spark discharge in water could be used to remove deposits from the filter membrane. The test setup included a circulating water loop and a pulsed power system. The present experiments used artificially hardened water with hardness of 1,000 mg/L of CaCO{sub 3} made from a mixture of calcium chloride (CaCl{sub 2}) and sodium carbonate (Na{sub 2}CO{sub 3}) in order to produce calcium carbonate deposits on the filter membrane. Spark discharge in water was found to produce strong shockwaves in water, and the efficiency of the spark discharge in cleaning filter surface was evaluated by measuring the pressure drop across the filter over time. Results showed that the pressure drop could be reduced to the value corresponding to the initial clean state and after that the filter could be maintained at the initial state almost indefinitely, confirming the validity of the present concept of pulsed spark discharge in water to clean dirty filter. The present study also investigated the effect of a plasma-assisted self-cleaning filter on the performance of physical water treatment (PWT) solenoid coil for the mitigation of mineral fouling in a concentric counterflow heat exchanger. The self-cleaning filter utilized shockwaves produced by pulse-spark discharges in water to continuously remove scale deposits from the surface of the filter, thus keeping the pressure drop across the filter at a relatively low value. Artificial hard water was used in the present fouling experiments for three different cases: no treatment, PWT coil only, and PWT coil plus self-cleaning filter. Fouling resistances decreased by 59-72% for the combined case of PWT coil plus filter compared with the values for no-treatment cases. SEM photographs showed much smaller particle sizes for the combined case of PWT coil plus filter as larger particles were continuously removed from circulating water by the filter. The x-ray diffraction data showed calcite crystal structures for all three cases.
Thermo hydraulic analysis and control of the HELOKA water cooling system
International Nuclear Information System (INIS)
In the framework of the European Fusion Program, various Helium cooled Test Blanket Modules (TBM), such as the Helium Cooled Pebble Bed (HCPB) blanket, are proposed for tests under reactor relevant experimental conditions in ITER. To qualify the TBM module design for ITER, it is necessary to test full size mock-ups in a helium loop under realistic pressure, temperature and flow conditions. The HCPB mock-ups will be tested at the Helium Loop Karlsruhe (HELOKA) test facility, at present in advanced status of design. As far as possible, HELOKA shall operate with requirements similar to those of the Helium coolant circuit of the TBM modules in ITER. One of the main requirements of the ITER main helium loop is its ancillary water cooling system, hence the need of a Water Cooling System (WCS) for HELOKA. An existing WCS, recently used for the COMET (Core Melt Accidents) experiment, is foreseen for this purpose. The system, designed in the 80's for a heat load of about 7 MW, will be used first for the HELOKA TBM experimental campaign, where the maximum expected heat load does not exceed 5 MW, and later on, for the Test Divertor Modules (TDM). The thermal hydraulic effect has been studied using the system code RELAP5, where the pumps, the heat exchanger (HX), the cooling tower, the valves, the piping, etc., can be modeled and the whole loop can be simulated for steady state, transient accident processes or cyclic operation. In order to improve the efficiency of the system and save energy, it has been proposed to install variable frequency converters for the electric drivers and new feedback controllers. An evaluation of the overall performances of the system with the proposed feedback controllers has been conducted with computer models developed with SIMULINK. At present most of the components have been modeled using manufacturer's data. For some components, technical data are scarce and therefore a comparison with experimental data to validate the models is planned. After the validation based on the experimental data, the code will allow the testing of the control strategies for steady state, transients or cyclic operation and check the possible upgrade of the system to 10 MW (expected heat load for the HELOKA TDM experimental campaign). The control system is being modernized using state of the art hardware and software components. The upgrade also includes additional sensors and a new data acquisition system. (author)
Hydrogen production using water cooled reactors
International Nuclear Information System (INIS)
Full text: Today the world is facing tremendous energy challenges. There is a demographic explosion, which even in the most conservative scenario will drive the energy demand to high levels whilst at the same time fossil resources are becoming scarcer, and more particularly oil which bears most of the weight in the transportation area. Global warming is also becoming a major concern as the last Intergovernmental Panel on Climate Change concluded that anthropogenic greenhouse gases (GHG) are responsible for most of the observed temperature increase since the middle of the twentieth century. To address these difficulties, the first step is to look for ways to save energy whenever possible. Then, the part of GHG free sources - renewable energies (wind, solar, hydraulic, biomass) as well as nuclear energy - has to be increased in electricity production. Lastly, since the part of electricity in the final consumption of energy is less than 20% worldwide, GHG free sources of energy have to look for other markets such as transportation, whether directly (electric cars) or indirectly via hydrogen (fuel cells) and/or process heat. Hydrogen is produced currently from fossil fuels (less than 5% is produced by splitting water), and production is increasing steadily, mostly because of its use for refining crude oil and the more demanding standards of purity required. This alone is already stimulating interest in producing hydrogen by sustainable means. Moreover, the hydrogen marketnable means. Moreover, the hydrogen market is bound to expand soon: hydrogen has been identified as a leading candidate for transport applications. A near term solution is to use the hydrogen produced together with a carbon source (biomass, coal, waste, CO2) to make synthetic fuel. A longer term and more hypothetical development could be the direct use of hydrogen to power cars. Hydrogen could also be used in the iron and cement industries as a reducing agent and also help these CO2 intensive industries to significantly decrease their GHG emissions. The French context has also to be taken into account. More than 80% of electricity is produced by nuclear power plants and the hour to hour variations of the electricity demand have to be absorbed by having some plants operating at intermediate power over significant periods of time. This situation presents the double drawback of not taking full benefit of an expensive investment as well as having to take careful steps when going back to full power in order to preserve the fuel cladding. Hydrogen production during off peak periods could help regulate the electricity demand and operate the nuclear plants in base load. This then requires hydrogen production means that are flexible and not investment intensive, as they would be used only on a part time basis. CEA's strategy is hence to focus on processes which could be coupled to nuclear plants or renewable energy sources and thus be able to produce hydrogen in a sustainable way, by splitting the water molecule using GHG free electricity and/or heat. Low temperature electrolysis, even if it is used currently for limited amounts, is a mature technology which uses only electricity and can be generalized in the near future. However, this technology, which requires about 4 kWh of electricity per Nm of hydrogen produced, is energy intensive and therefore three advanced processes have also been investigated: High temperature steam electrolysis (HTSE), the Sulfur-Iodine (S-I) and Hybrid sulfur (HyS) thermochemical cycles. These processes look promising but the last two require the development of high temperature reactors, still necessitate extensive R and D work and will not be mature for industrial development within the next 20 years. Therefore, beside the optimization of LTE, our focus will be on HTSE, which will be available sooner and can also operate in autothermal mode, offering the capacity to be coupled to a LWR. In this paper, we will present the French road map for hydrogen production. (author)
Techtronics Program,
Student groups are challenged to design and construct model towers out of newspaper. They are given limited supplies including newspaper, tape and scissors, paralleling the real-world limitations faced by engineers, such as economic restrictions as to how much material can be used in a structure. Students aim to build their towers for height and stability, as well as the strength to withstand a simulated lateral "wind" load.
Kelly Devereaux
Learners work in groups to design and build a tower out of balsa wood. As a motivator, they can compete to build a tower with the highest strength-to-weight ratio. Learners draw structurally sound 2D designs in the first part of the activity, then use those designs to construct the 3D structure. This activity is best used as a part of a larger lesson or after other building activities. Time for activity can be split over multiple meetings.
Silver ionization water purification technology was originally developed for Apollo spacecraft. It was later used to cleanse swimming pools and has now been applied to industrial cooling towers and process coolers. Sensible Technologies, Inc. has added two other technologies to the system, which occupies only six square feet. It is manufactured in three capacities, and larger models are custom built on request. The system eliminates scale, corrosion, algae, bacteria and debris, and because of the NASA technology, viruses and waterborne bacteria are also destroyed. Applications include a General Motors cooling tower, amusement parks, ice manufacture and a closed-loop process cooling system.
W-030, AY/AZ tank farm cooling and miscellaneous instrumentation
International Nuclear Information System (INIS)
This is the acceptance test report for construction functional testing of Project W-030 cooling systems and related instrumentation. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The Tank Farm Cooling System consists of four forced draft cooling towers, a chilled water system, and associated controls
30 CFR 250.248 - What solid and liquid wastes and discharges information and cooling water intake information must...
...discharges information and cooling water intake information must accompany the...discharges information and cooling water intake information must accompany the...discharges information and cooling water intake information must accompany...
30 CFR 250.217 - What solid and liquid wastes and discharges information and cooling water intake information must...
...discharges information and cooling water intake information must accompany the...discharges information and cooling water intake information must accompany the...discharges information and cooling water intake information must accompany...
Numerical simulation of the effects of cooling tower complexes on clouds and severe storms. Final report, September 1976-June 1979
International Nuclear Information System (INIS)
A two-dimensional, time-dependent model was developed which gives realistic simulations of many severe storm processes - such as heavy rains, hail, and strong winds. The model is a set of partial differential equations describing time changes of momentum, energy, and mass (air and various water substances such as water vapor, cloud liquid, cloud ice, rainwater, and hail). In addition, appropriate boundary And initial conditions (taken from weather sounding data) are imposed on a domain approximately 20 km high by 20 km wide with 200 m grid intervals to complete the model. Modifications were made to the model which allow additional water vapor and heat to be added at several lower grid points, simulating effluents from a power park. Cases were run which depict realistic severe storm situations. One atmospheric sounding has a strong middle-level inversion which tends to inhibit the first convective clouds but gives rise later to a severe storm with hail and heavy rains. One other sounding is taken from a day in which a severe storm occurred in the Miami area. A third sounding depicts atmospheric conditions in which severe storms formed in the vicinity of Huron, South Dakota. The results indicate that a power park emitting 80% latent heat and 20% sensible heat has little effect on the simulated storm. A case with 100% sensible heat emission leads to a much different solution, with the simulated storm reduced in severity and the rain and hail redistributed. A case in whicain and hail redistributed. A case in which water vapor is accumulated in a region and released over a broad depth results in sightly more rain from a severe storm
Economic competitiveness requirements for evolutionary water cooled reactors
International Nuclear Information System (INIS)
This paper analyses the necessary economic conditions for evolutionary water cooled reactors to be competitive. Utilising recent national cost data for fossil-fired base load plants expected to be commissioned by 2005 -2010, target costs for nuclear power plants are discussed. Factors that could contribute to the achievement of those targets by evolutionary water cooled reactors are addressed. The feed-back from experience acquired in implementing nuclear programmes is illustrated by some examples from France and the Republic of Korea. The paper discusses the impacts on nuclear power competitiveness of globalisation and deregulation of the electricity market and privatisation of the electricity sector. In addition, issues related to external cost internalisation are considered. (author)
Balancing passive and active systems for evolutionary water cooled reactors
International Nuclear Information System (INIS)
Advanced concepts of the water-cooled reactors are intended to improve safety, economics and public perception of nuclear power. The potential inclusion of new passive means in addition or instead of traditional active systems is being considered by nuclear plant designers to reach these goals. With respect to plant safety, application of the passive means is mainly intended to simplify the safety systems and to improve their reliability, to mitigate the effect of human errors and equipment malfunction. However, some clear drawbacks and the limited experience and testing of passive systems may raise additional questions that have to be addressed in the design process for each advanced reactor. Therefore the plant designer should find a reasonable balance of active and passive means to effectively use their advantages and compensate their drawbacks. Some considerations that have to be taken into account when balancing active/passive means in advanced water-cooled reactors are discussed in this paper. (author)
Passive safety features in current and future water cooled reactors
International Nuclear Information System (INIS)
Better understanding of the passive safety systems and components in current and future water-cooled reactors may enhance the safety of present reactors, to the extend passive features are backfitted. This better understanding should also improve the safety of future reactors, which can incorporate more of these features. Passive safety systems and components may help to prevent accidents, core damage, or release radionuclides to the environment. The Technical Committee Meeting which was hosted by the USSR State Committee for Utilization of Nuclear Energy was attended by about 80 experts from 16 IAEA Member States and the NEA-OECD. A total of 21 papers were presented during the meeting. The objective of the meeting was to review and discuss passive safety systems and features of current and future water cooled reactor designs and to exchange information in this area of activity. A separate abstract was prepared for each of the 21 papers published in this proceedings. Refs, figs and tabs
Water Cooled TJ Dense Array Modules for Parabolic Dishes
International Nuclear Information System (INIS)
AZUR SPACE Solar Power GmbH has developed a novel type of dense array module for use in parabolic dishes. Such dishes never produce a perfectly homogeneous, rectangular light spot but an inhomogeneous light distribution. A regular module would use this light distribution very inefficiently. Therefore AZUR SPACE developed a dense array module concept which can be adapted to inhomogeneous light spots. It is populated with state of the art triple junction solar cells.The modules are designed for light intensities in the range of 50-100 W/cm2 and are actively water cooled. Prototypes are installed in 11 m2 parabolic dishes produced by Zenith Solar. A peak output of 2.3 kW electrical and 5.5 kW thermal power could be demonstrated. The thermal power may be used for solar heating, solar cooling or warm water.
Corrosion induced clogging and plugging in water-cooled generator cooling circuit
International Nuclear Information System (INIS)
Water-cooled electrical generators have been experienced corrosion-related problems that are restriction of flow through water strainers caused by collection of excessive amounts of copper corrosion products (''clogging''), and restriction of flow through the copper strands in the stator bars caused by growth or deposition of corrosion products on the walls of the hollow strands (''plugging''). These phenomena result in unscheduled shutdowns that would be a major concern because of the associated loss in generating capacity. Water-cooled generators are operated in one of two modes. They are cooled either with aerated water (dissolved oxygen >2 ppm) or with deaerated water (dissolved oxygen <50 ppb). Both modes maintain corrosion rates at satisfactorily low levels as long as the correct oxygen concentrations are maintained. However, it is generally believed that very much higher copper corrosion rates result at the intermediate oxygen concentrations of 100-1000 ppb. Clogging and plugging are thought to be associated with these intermediate concentrations, and many operators have suggested that the period of change from high-to-low or from low-to-high oxygen concentration is particularly damaging. In order to understand the detailed mechanism(s) of the copper oxide formation, release and deposition and to identify susceptible conditions in the domain of operating variables, a large-scale experiments are conducted using six hollow strands of full length connected with physico-chemically scaled generator cooling water circuit. To ensure a close simulation of thermal-hydraulic conditions in a generator stator, strands of the loop will be ohmically heated using AC power supply. Experiments is conducted to cover oxygen excursions in both high dissolved oxygen and low dissolved oxygen conditions that correspond to two representative operating condition at fields. A thermal upset condition is also simulated to examine the impact of thermal stress. During experiments, particle size distribution and microstructure of copper surface as well as water pH, conductivity and ORP, dissolved gases including oxygen and hydrogen is monitored as on-line. (authors)
Results of cooling of dies with water mist
R.W?adysiak; S. Pietrowski
Purpose: Intensification of die casting of car silumins wheels with use of the water mist instead of compressed air dies cooling in low pressure casting process were presented in the paper.Design/methodology/approach: Examinations of casting process parameters were carried out on the industrial workstation of casting car wheels under the low pressure and also with Magma computer simulating system.Findings: The temperature and the range of its variation were presented in characteristic points ...
International Nuclear Information System (INIS)
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) pool water treatment and cooling system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998)
Advanced water-cooled phosphoric acid fuel cell development
International Nuclear Information System (INIS)
The objective of this research and development effort is to improve the performance and minimize the cost of the existing water-cooled, phosphoric acid fuel cell stack technology. The improved stack technology shall be capable of demonstrating a power density of at least 175 watts per square foot over a 40,000 hour useful life and a projected manufactured cost of less than $400 per kilowatt in initial production for electric utility applications
Advanced technologies for water cooled reactors 1990. Pt. 2
International Nuclear Information System (INIS)
The main purpose of the meeting was to review and discuss the status of national programmes, the progress achieved since the last meeting held in June 1988 in the field of advanced technologies and design trends for existing and future water cooled reactors. 24 specialists from 14 countries and the IAEA took part in the meeting and 12 papers were presented. A separate abstract was prepared for each of these papers. Refs, figs and tabs
Estimation of the amount of surface contamination of a water cooled nuclear reactor by cooling water analysis
International Nuclear Information System (INIS)
Calculations, based upon on-the-spot measurements, were performed to estimate the contamination of NPP primary circuit and spent fuel storage pool solid surfaces via the composition of the cooling water in connection with a non-nuclear incident in the Paks NPP. Thirty partially burnt-up fuel element bundles were damaged during a cleaning process, an incident which resulted in the presence of fission products in the cooling water of the cleaning tank (CT) situated in a separate pool (P1). Since this medium was in contact for an extended period of time with undamaged fuel elements to be used later and also with other structural materials of the spent fuel storage pool (SP), it was imperative to assess the surface contamination of these latter ones with a particular view to the amount of fission material. In want of direct methods, one was restricted to indirect information which rested mainly on the chemical and radiochemical data of the cooling water. It was found that (i) the most important contaminants were uranium, plutonium, cesium and cerium; (ii) after the isolation of P1 and SP and an extended period of filtering the only important contaminants were uranium and plutonium; (iii) the surface contamination of the primary circuit (PC) was much lower than that of either SP or P1; (iv) some 99% of the contamination was removed from the water by the end of the filtering process
Ecotoxicological investigation in cooling water reservoirs of NPP and Dnepr cascade water reservoirs by using biotest
International Nuclear Information System (INIS)
Investigation data obtained during 1988-1992 have shown that NPP waste waters effected test-organisms: they induced changes in growth intensity and morphology of Spirodela polyrrhiza and high mortality of spawn and larvae of Salmo gairdneri as well as somatic mutations and mortality in Tradescantia SLC system. It indicates that toxic matters discharge to cooling reservoirs with NPP waste waters. Similar levels of toxicity and genotoxicity were found in Ignalina and Leningrad NPP waste waters, as well as in cooling reservoirs waters. The water of Dnepr cascade reservoirs was more eutrophic, toxic and genotoxic than the water of NPP cooling reservoirs. Water genotoxicity in the Dnepr cascade water reservoirs was equal to that of NPP waste waters. The Kiev reservoir water showed the highest genotoxicity.Bottom sediments of some biotopes of Kiev and Kachovsk water reservoirs were found to be the most genotoxic. The genotoxicity of these bottom sediments was equal to the Ignalina NPP EDS waste water treatment plant sludge, which commonly is utilized as hazardous waste. The use of test-organism system allows to estimate more precisely ecotoxicological situation in water reservoirs - to establish their eutrophic level, to identify radioactive and chemical water and bottom sediments pollution and to reveal synergetic effects of pollutant complex effect. 8 refs., 6 tabs
An overview of Supercritical Water-Cooled Reactor (SCWR) concepts
International Nuclear Information System (INIS)
Nuclear energy will playa big part in being part of the future energy mix since it offers a relatively clean, safe and reliable source of energy. Next generation nuclear energy technologies (Generation IV) are being developed around the world that offers innovative core designs and fuel cycles. Supercritical Fluids (SCFs) have been proposed for Gen IV thermodynamic cycles to achieve high thermal efficiencies. Super Critical Water-Cooled Reactor (SCWR) is one of the proposed Gen IV design relying heavily on the use of SC Water for heat transfer. This abstract presents the latest developments on SCWR concepts around the world. (author)
Experimental Studies of NGNP Reactor Cavity Cooling System With Water
Energy Technology Data Exchange (ETDEWEB)
Corradini, Michael; Anderson, Mark; Hassan, Yassin; Tokuhiro, Akira
This project will investigate the flow behavior that can occur in the reactor cavity cooling system (RCCS) with water coolant under the passive cooling-mode of operation. The team will conduct separate-effects tests and develop associated scaling analyses, and provide system-level phenomenological and computational models that describe key flow phenomena during RCCS operation, from forced to natural circulation, single-phase flow and two-phase flow and flashing. The project consists of the following tasks: Task 1. Conduct separate-effects, single-phase flow experiments and develop scaling analyses for comparison to system-level computational modeling for the RCCS standpipe design. A transition from forced to natural convection cooling occurs in the standpipe under accident conditions. These tests will measure global flow behavior and local flow velocities, as well as develop instrumentation for use in larger scale tests, thereby providing proper flow distribution among standpipes for decay heat removal. Task 2. Conduct separate-effects experiments for the RCCS standpipe design as two-phase flashing occurs and flow develops. As natural circulation cooling continues without an ultimate heat sink, water within the system will heat to temperatures approaching saturation , at which point two-phase flashing and flow will begin. The focus is to develop a phenomenological model from these tests that will describe the flashing and flow stability phenomena. In addition, one could determine the efficiency of phase separation in the RCCS storage tank as the two-phase flashing phenomena ensues and the storage tank vents the steam produced. Task 3. Develop a system-level computational model that will describe the overall RCCS behavior as it transitions from forced flow to natural circulation and eventual two-phase flow in the passive cooling-mode of operation. This modeling can then be used to test the phenomenological models developed as a function of scale.
Some aspects of cooling water discharges and environmental enhancement
International Nuclear Information System (INIS)
As a consequence of the effects of cooling water discharge on the environment, the siting of nuclear power plants is approached with cautiousness. The pros and cons are discussed of siting near bodies of good quality water or in more densely populated or industrial areas. Properties and effects of thermal discharges are elaborated. The effects of heat on the activity of individual organisms, on the accumulation of organic material, on the mineralization rate of organic matter and on the transport of oxygen all have influences on recipient water bodies. Examples of siting Swedish thermal power stations are described and these indicate some negative effects. However, the results do not repudiate the possibility of good effects from the design of new cooling water intake and discharge systems that would speed up the mineralization of organic matters by addition of heat and oxygen. It is concluded that, when choosing between possible sites, areas should be selected where the available energy of the discharge can be used to improve water quality. (author)
Development Project of Supercritical-water Cooled Power Reactor
International Nuclear Information System (INIS)
A Supercritical-water Cooled Power Reactor (SCPR) development project (Feb. 2001- Mar. 2005) is being performed by a joint team consisting of Japanese universities and nuclear venders with a national fund. The main objective of this project is to provide technical information essential to demonstration of SCPR technologies through concentrating three sub-themes: 'plant conceptual design', 'thermohydraulics', and 'material and water chemistry'. The target of the 'plant conceptual design sub-theme' is simplify the whole plant systems compared with the conventional LWRs while achieving high thermal efficiency of more than 40 % without sacrificing the level of safety. Under the 'thermohydraulics sub-theme', heat transfer characteristics of supercritical-water as a coolant of the SCPR are examined experimentally and analytically focusing on 'heat transfer deterioration'. The experiments are being performed using fron-22 for water at a fossil boiler test facility. The experimental results are being incorporated in LWR analytical tools together with an extended steam/R22 table. Under the 'material and water chemistry sub-theme', material candidates for fuel claddings and internals of the SCPR are being screened mainly through mechanical tests, corrosion tests, and simulated irradiation tests under the SCPR condition considering water chemistry. In particular, stress corrosion cracking sensitivity is being investigated as well as uniform corrosion and swelling characteristicsorm corrosion and swelling characteristics. Influences of water chemistry on the corrosion product characteristics are also being examined to find preferable water condition as well as to develop rational water chemistry controlling methods. (authors)
Power handling capability of water-cooled beam stops
International Nuclear Information System (INIS)
Doubling the beam power on the RFQ1-1250 linear accelerator at Chalk River and designing a 40 kW beam diagnostic system for Tokamak de Varennes required a detailed investigation into the power handling capabilities of beam stops. Different techniques for augmentation of the critical heat flux on the cooling channel surface of beam stops are reviewed. In the case of a beam stop with twisted tape inserts, the swirl flow condition yields a higher critical heat flux than that of a straight axial flow. Although a critical heat flux in the order of 10 kW/cm2 could be obtained at high flow velocities such as 45 m/s, such flows are not always practical in the design of beam stop cooling systems. At a water velocity of 4 m/s, the highest beam power density is estimated to be 1.4 kW/cm2 for a beam stop design that uses double rows of cooling tubes. A similar design, where cooling channels are machined on a common copper block, would handle a power density up to 2.6 kW/cm2. Some preliminary hydraulic test results, related to a third design where high flow turbulence is created by two rows of intersected-channels, are also reported. (Author) 5 refs., 4 figs
Cooling water treatment for heavy water project (Paper No. 6.9)
International Nuclear Information System (INIS)
With minor exceptions, water is the preferred industrial medium for the removal of unwanted heat from process systems. The application of various chemical treatments is required to protect the system from water related and process related problems of corrosion, scale and deposition and biofouling. The paper discusses the cooling water problems for heavy water industries along with the impact caused by associated fertilizer units. (author). 6 figs
Analysis of Steam Condensation in a Finned Tube of Air-Water Combined Cooling System
International Nuclear Information System (INIS)
A Passive Auxiliary Feedwater System (PAFS) is one of the passive cooling systems of the existing power plant and the operating period is 8 hours because of the limited capacity of the cooling water tank. Therefore, to increase the operating period from 8 to 72 hours for an existing PAFS, the capacity of the cooling water tank should be increased up to 3-4 times. To resolve the excessive increase of the cooling tank volume in water cooling systems, an air-water combined passive cooling system is proposed. In this combined cooling system, the core cooling during the initial stage of an accident having high decay power depends on the water cooling systems such as PAFS. For the later phase of an accident, an air-cooling system is applied to the core cooling. In the operation of the air-cooling system, the steam from the cooling water tank of the PAFS is condensed and recirculated to the cooling water tank by an air-cooling heat exchanger. In this way, the increase of the cooling water tank volume can be minimized. To design an air-water combined cooling system, the steam condensation characteristics of an air-cooling heat exchanger tube was calculated using a CFX code. The results show that the air velocities around the tube at the steam inlet/outlet regions are quite different with each other. Therefore, dense installation of thermocouples at the tube bottom region is required to measure the steam condensation in the tube. Otherwise, the detection and measurement of steam condensation at the steam inlet region may be very difficult. The velocity distribution of air is not uniform and the distributions of air temperature and velocity around the heat exchanger tube are strongly asymmetric. In the design of the measurement system of the test facility, the problems mentioned above should be considered
A water-cooled 13-kG magnet system
International Nuclear Information System (INIS)
The construction, performance, and reliability of a high field magnet system are reported. The magnet is designed to generate a flat top 13 kG magnetic induction required for the operation of a 35 GHz, 100 k W gyrotron under development at INPE. The system comprises three solenoids, located in the gun, cavity, and collector regions, consisting of split pair magnets with the field direction vertical. The magnets are wound from insulated copper tube whose rectangular cross section has 5.0 mm-diameter hole leading the cooling water. On account of the high power (? 100 k W) supplied to the cavity coils, it turned out necessary to employ a cooling system which includes hydraulic pump a heat exchanger. The collector and gun magnets operate at lower DC current (? 150 A), and, in this case, flowing water provided by wall pipes is far enough to cool down the coils. In addition, a 250 k V A high power AC/DC Nutek converser is used to supply power to the cavity magnet. For the collector and gun magnets, 30 V/600 A DC power supplies are used. (author)
What causes cooling water temperature gradients in forested stream reaches?
Garner, G.; Malcolm, I. A.; Sadler, J. P.; Hannah, D. M.
Previous studies have suggested that shading by riparian vegetation may reduce maximum water temperature and provide refugia for temperature sensitive aquatic organisms. Longitudinal cooling gradients have been observed during the daytime for stream reaches shaded by coniferous trees downstream of clear cuts, or deciduous woodland downstream of open moorland. However, little is known about the energy exchange processes that drive such gradients, especially in semi-natural woodland contexts, and in the absence of potentially confounding cool groundwater inflows. To address this gap, this study quantified and modelled variability in stream temperature and heat fluxes along an upland reach of the Girnock Burn (a tributary of the Aberdeenshire Dee, Scotland) where riparian landuse transitions from open moorland to semi-natural forest. Observations were made along a 1050 m reach using a spatially-distributed network of ten water temperature micro-loggers, three automatic weather stations and >200 hemispherical photographs, which were used to estimate incoming solar radiation. These data parameterised a high-resolution energy flux model, incorporating flow-routing, which predicted spatio-temporal variability in stream temperature. Variability in stream temperature was controlled largely by energy fluxes at the water column-atmosphere interface. Predominantly net energy gains occurred along the reach during daylight hours, and heat exchange across the bed-water column interface accounted for energy budget. For periods when daytime net radiation gains were high (under clear skies), differences between water temperature observations decreased in the streamwise direction; a maximum difference of 2.5 �C was observed between the upstream reach boundary and 1050 m downstream. Furthermore, daily maximum water temperature at 1050 m downstream was ?1�C cooler than at the upstream reach boundary and lagged the occurrence of daily maximum water temperature upstream by >1h. Temperature gradients were not generated by cooling of stream water, but rather by a combination of reduced rates of heating in the woodland reach and advection of cooler (overnight and early morning) water from the upstream moorland catchment. Longitudinal thermal gradients were indistinct at night and on days when net radiation gains were low (under over-cast skies), thus when changes in net energy gains or losses did not vary significantly in space and time, and heat advected into the reach was reasonably consistent. The findings of the study and the modelling approach employed are useful tools for assessing optimal planting strategies for mitigating against ecologically damaging stream temperature maxima.
Supercritical Water-Cooled Reactor (SCWR) Development through GIF Collaboration
International Nuclear Information System (INIS)
The Generation IV International Forum (GIF) was established to conduct collaborative research and development (R and D) that will lead to the development of fourth generation advanced nuclear energy systems. Six concepts were selected for further development through GIF collaboration, among which the Supercritical Water-Cooled Reactor (SCWR) is the only GIF concept that uses water as coolant and is, therefore, a natural evolution of current advanced water-cooled reactor technologies. The SCWR operates above the thermodynamic critical point (374oC, 22.1 MPa). The main advantage of the SCWR is improved economics because of the higher thermal efficiency and the potential for plant simplification. Two design options are considered for the SCWR: a) pressure vessel and b) pressure tube designs. The R and D needs for assessing the technical feasibility (e.g., thermal-hydraulics, materials, water chemistry, etc.) are common to both designs, and provide valuable collaboration opportunities for countries and organizations pursuing either option. Major features of the SCWR, various conceptual designs under consideration by the GIF SCWR members, and GIF collaboration target and R and D plan are presented in this paper. (author)
Thermophysical properties of materials for water cooled reactors
International Nuclear Information System (INIS)
The IAEA Co-ordinated Research Programme (CRP) to establish a thermophysical properties data base for light and heavy water reactor materials was organized within the framework of the IAEA's International Working Group on Advanced Technologies for Water Cooled Reactors. The work within the CRP started in 1990. The objective of the CRP was to collect and systemaize a thermophysical properties data base for light and heavy water reactor materials under normal operating, transient and accident conditions. The important thermophysical properties include thermal conductivity, thermal diffusivity, specific heat capacity, enthalpy, thermal expansion and others. These properties as well as the oxidation of zirconium-based alloys, the thermophysical characteristics of high temperature concrete-core melt interaction and the mechanical properties of construction materials are presented in this report. It is hoped that this report will serve as a useful source of thermophysical properties data for water cooled reactor analyses. The properties data are maintained on the THERSYST system at the University of Stuttgart, Germany and are internationally available. Refs, figs, tabs
Corrosion issues in cooling water circuits of nuclear power plants
International Nuclear Information System (INIS)
Nuclear power plants cooling water circuits are required to refresh the vapour which is used to produce electricity. Raw oxygenated water, at temperature between ambient and 50 C is used for this purpose. It can lead to severe corrosion problems for many materials. This paper presents some of the main corrosion issues that were encountered in EDF cooling water circuits since their installation and explains how they were deal with. Corrosion problems were encountered on condenser tubes, condenser water boxes, pumping systems, and on different others devices. Cases involving carbon steels, low alloy steels, copper alloys and stainless steels are reported. The different forms of corrosion which were encountered are galvanic corrosion, erosion-corrosion, crevice corrosion, pitting corrosion and stress corrosion cracking. In some cases, bio-corrosion was also involved. In the different examples which are chosen, the different measures which were taken to cope with the issue are presented: material removing, cathodic protection, painting systems, procedure for out-of-work conservation and actions to ensure circuit properties are briefly discussed. (authors)
Mission Science Workshop
In this activity, learners build magnetic towers to explore the forces and properties of magnets. This activity allows learners to experiment and play with magnets and feel first-hand the force of magnets pushing and pulling. Note: this activity requires the use of a drill and saw, which are not included in the cost of materials.
Implementation of new core cooling monitoring system for light water reactors - BCCM (Becker Core Cooling Monitor)
International Nuclear Information System (INIS)
Core cooling monitors are key instruments to protect reactors from large accidents due to loss of coolant. Sensors presented here are based on resistance thermometry. Temperature dependent resistance is powered by relatively high and constant current. Value of this resistance depends on thermal exchange with coolant and when water is no more surrounding the sensors a large increase of temperature is immediately generated. The same instrument can be operated with low current and will measure the local temperature up to 1260oC in case of loss of coolant accident. Sensors are manufactured with very few components and materials already qualified for long term exposure to boiling or pressurized water reactors environment. Prototypes have been evaluated in a test loop up to 160 bars and in the Barsebaeck-1 reactor. Industrial sensors are now in operation in reactor Oskarshamn 2. (author)
Environmental compatible cooling water treatment chemicals; Umweltvertraegliche Chemikalien in der Kuehlwasserkonditionierung
Energy Technology Data Exchange (ETDEWEB)
Gartiser, S.; Urich, E.
In Germany about 32 billion m{sup 3}/a cooling water are discharged from industrial plants and power industry. These are conditioned partly with biocides, scaling and corrosion inhibitors. Within the research project the significance of cooling water chemicals was evaluated, identifying the chemicals from product information, calculating their loads from consumption data of more than 180 cooling plants and investigating the basic data needed for an environmental hazard assessment. Additionally the effects of cooling water samples and products were determined in biological test systems. Batch tests were performed under defined conditions in order to measure the inactivation of cooling water biocides. (orig.)
Pink-Beam, Highly-Accurate Compact Water Cooled Slits
International Nuclear Information System (INIS)
Advanced Design Consulting, Inc. (ADC) has designed accurate compact slits for applications where high precision is required. The system consists of vertical and horizontal slit mechanisms, a vacuum vessel which houses them, water cooling lines with vacuum guards connected to the individual blades, stepper motors with linear encoders, limit (home position) switches and electrical connections including internal wiring for a drain current measurement system. The total slit size is adjustable from 0 to 15 mm both vertically and horizontally. Each of the four blades are individually controlled and motorized. In this paper, a summary of the design and Finite Element Analysis of the system are presented
What causes cooling water temperature gradients in forested stream reaches?
Directory of Open Access Journals (Sweden)
G. Garner
Full Text Available Previous studies have suggested that shading by riparian vegetation may reduce maximum water temperature and provide refugia for temperature sensitive aquatic organisms. Longitudinal cooling gradients have been observed during the daytime for stream reaches shaded by coniferous trees downstream of clear cuts, or deciduous woodland downstream of open moorland. However, little is known about the energy exchange processes that drive such gradients, especially in semi-natural woodland contexts, and in the absence of potentially confounding cool groundwater inflows. To address this gap, this study quantified and modelled variability in stream temperature and heat fluxes along an upland reach of the Girnock Burn (a tributary of the Aberdeenshire Dee, Scotland where riparian landuse transitions from open moorland to semi-natural forest. Observations were made along a 1050 m reach using a spatially-distributed network of ten water temperature micro-loggers, three automatic weather stations and >200 hemispherical photographs, which were used to estimate incoming solar radiation. These data parameterised a high-resolution energy flux model, incorporating flow-routing, which predicted spatio-temporal variability in stream temperature. Variability in stream temperature was controlled largely by energy fluxes at the water column�atmosphere interface. Predominantly net energy gains occurred along the reach during daylight hours, and heat exchange across the bed-water column interface accounted for 1h. Temperature gradients were not generated by cooling of stream water, but rather by a combination of reduced rates of heating in the woodland reach and advection of cooler (overnight and early morning water from the upstream moorland catchment. Longitudinal thermal gradients were indistinct at night and on days when net radiation gains were low (under over-cast skies, thus when changes in net energy gains or losses did not vary significantly in space and time, and heat advected into the reach was reasonably consistent. The findings of the study and the modelling approach employed are useful tools for assessing optimal planting strategies for mitigating against ecologically damaging stream temperature maxima.
Experimental study of swirl flow patterns in Gas Conditioning Tower at various entry conditions
DEFF Research Database (Denmark)
Jinov, Andrei A.; Larsen, Poul Scheel
In a gas conditioning tower hot flue gas with relatively high dust loads is cooled by injecting water spray near the top. For satisfactory operation wet particles should be kept off walls and all water should have evaporated to yield a uniformly cooled flow before it reaches the bottom of the tower. For practical reasons and space limitations the gas often enters through an inlet pipe making a 150-180� bend shortly before a short diffuser expanding to full tower diameter (Fig. 1). A swirl generator is placed immediately before the inlet to the diffuser to prevent recirculation near walls of the diffuser where cooling water is introduced and improve pressure recovery.Previous experimental studies [1] with a short, axial inlet pipe have shown that the distribution of axial flow could be improved considerably by inserting a swirl generator at the inlet to thediffuser. This gives strong back flow only in the central part of the diffuser. But actual designs involve a number of different designs of the inlet pipe, usually having a 150-180� sharp bend. The present experimental study is aimed at determining the influence of the inlet pipe design on the resulting flow in the upper part of the tower. The study is carried out using LDA-measurements and flow visualization in a 1:16 scale laboratory model. In addition, the degree of mixing on injected water spray is simulated by visualization studies to find the optimal position of injection nozzles.
Kinetic model for the chlorination of power plant cooling waters
International Nuclear Information System (INIS)
Concern over the environmental effects of chlorination has prompted efforts to minimize the amount of chlorine necessary to prevent fouling of power-plant condensers. Kinetic expressions are developed for the short-term reactions of chlorine consumption by organic substances in natural freshwater. These expressions were developed to use in a kinetic model to predict the free and total available chlorine discharged in cooling water. This model uses commonly available water-quality data. It assumes that most of the chlorine-consuming substances are: (1) NH3, (2) chloramine-forming organic-N, and (3) humic substances. It uses the Morris-Wei model of chlorine-ammonia reactions. Chloramine formation from organic-N was represented by a model compound, glycylglycine
Water-cooled solid-breeder concept for ITER
International Nuclear Information System (INIS)
A water-cooled solid-breeder blanket concept was developed for ITER. The main function of this blanket is to produce the necessary tritium for the ITER operation. Several design features are incorporated in this blanket concept to increase its attractiveness. It is assumed that the blanket operation at commercial power reactor conditions can be sacrificed to achieve a high tritium breeding ratio with minimum additional research and development, and minimal impact on reactor design and operation. Operating temperature limits are enforced for each material to insure a satisfactory blanket performance. In fact, the design was iterated to maximize the tritium breeding ratio and satisfy these temperature limits. The other design constraint is to permit a large increase in the neutron wall loading without exceeding the temperature limits for the different blanket materials. The blanket concept contains 1.8 cm of Li2O and 22.5 cm of beryllium both with a 0.8 density factor. The water coolant is isolated from the breeder material by several zones which reduces the tritium buildup in the water by permeation, reduces the chance for water-breeder interaction, and permits the breeder to operate at high temperature with a low temperature coolant. This improves the safety and environmental aspects of the blanket and eliminates the costly process of the tritium recovery from the water. The key features and design analysis of this blanket are summarized in this paper. 11 refs., 2 figs., 3 tabs
International Nuclear Information System (INIS)
The primary responsibility of an intrusion detection system (IDS) operator is to monitor the system, assess alarms, and summon and coordinate the response team when a threat is acknowledged. The tools currently provided to the operator are somewhat limited: monitors must be switched, keystrokes must be entered to call up intrusion sensor data, and communication with the response force must be maintained. The Virtual tower is an operator interface assembled from low-cost commercial-off-the-shelf hardware and software; it enables large amounts of data to be displayed in a virtual manner that provides instant recognition for the operator and increases assessment accuracy in alarm annunciator and control systems. This is accomplished by correlating and fusing the data into a 360-degree visual representation that employs color, auxiliary attributes, video, and directional audio to prompt the operator. The Virtual Tower would be a valuable low-cost enhancement to existing systems
Major rehabilitation of the Bruce A heat transport heavy water upgrader and effect on overall upgrader system and tower packing performance
International Nuclear Information System (INIS)
Before shutdown in 1997, the Bruce A Heat Transport Heavy Water Upgrader was unable to produce high purity heavy water. Following rehabilitation in 2006-2009, upgrader performance was fully restored, significantly increasing site heavy water capability to support operating units. This paper describes the major modifications and maintenance. The main cause of poor product quality was not packing degradation, as previously thought, but a severely fouled reboiler and poor process control. Performance data, including tower isotopic profile is provided. A simulation model was developed to improve monitoring and optimize performance. The model is used to estimate the number of theoretical plates in the column. (author)
Cooling performance of R510A in domestic water purifiers
International Nuclear Information System (INIS)
Cooling performance of R510A is examined both numerically and experimentally in an effort to replace HFC134a in the refrigeration system of domestic water purifiers. Although the use of HFC134a is currently dominant, it is being phased out in Europe and most developed countries due to its high potential contribution to global warming. To solve this problem, cycle simulation and experimental measurements are conducted with a new refrigerant mixture of 88%RE170/12%R600a using actual domestic water purifiers. This mixture has been recently numbered and listed as R510A by ASHRAE. Test results show that, due to the small internal volume of the refrigeration system of the domestic water purifiers, system performance with R510A is greatly influenced by the amount of charge. With the optimum charge amount of 20 to 21 g, approximately 50% that of HFC134a, the energy consumption of R510A is 22.3% lower than that of HFC134a. The compressor discharge temperature of R510A is 3.7 .deg. C lower than that of HFC134a at the optimum charge. Overall, R510A, a new, long term, and environmentally safe refrigerant, is a good alternative for HFC134a. Furthermore, it requires only minor changes in the refrigeration system of the domestic water purifiers
Candidate Materials Evaluation for Supercritical Water-Cooled Reactor
International Nuclear Information System (INIS)
Final technical report on the corrosion, stress corrosion cracking, and radiation response of candidate materials for the supercritical water-cooled reactor concept. The objective of the proposed research was to investigate degradation of materials in the supercritical water environment (SCW). First, representative alloys from the important classes of candidate materials were studied for their corrosion and stress-corrosion cracking (SCC) resistance in supercritical water. These included ferritic/martensitic (F/M) steels, austenitic stainless steels, and Ni-base alloys. Corrosion and SCC tests were conducted at various temperatures and exposure times, as well as in various water chemistries. Second, emerging plasma surface modification and grain boundary engineering technologies were applied to modify the near surface chemistry, microstructure, and stress-state of the alloys prior to corrosion testing. Third, the effect of irradiation on corrosion and SCC of alloys in the as-received and modified/engineered conditions were examined by irradiating samples using high-energy protons and then exposing them to SCW
European supercritical water cooled reactor (HPLWR Phase 2 project)
International Nuclear Information System (INIS)
The High Performance Light Water Reactor (HPLWR), how the European Supercritical Water Cooled Reactor is called, is a pressure vessel type reactor operated with supercritical water at 25 MPa feedwater pressure and 500 deg C maximum core outlet temperature. It is designed and analyzed by a European consortium of 13 partners from 8 Euratom member states in the second phase of the HPLWR project. Most emphasis has been laid on a core with a thermal neutron spectrum, consisting of small, housed fuel assemblies with 40 fuel pins each and a central water box to improve the neutron moderation despite the low coolant density. Peak cladding temperatures of the fuel rods have been minimized by heating up the coolant in three steps with intermediate coolant mixing. The innovative core design with upward and downward flow through its assemblies has been studied with neutronic, thermal-hydraulic and stress analyses and has been reviewed carefully in a mid-term assessment. The containment design with its safety and residual heat removal systems is based on the latest boiling water reactor concept, but with different passive high pressure coolant injection systems to cause a forced convection through the core. The design concept of the steam cycle is indicating the envisaged efficiency increase to around 44%. Moreover, it provides the constraints to design the components of the balance of the plant. The project is accompanied by numerical studies of heat transfer of supercritical water in fuel assemblies and by material tests of candidate cladding alloys, performed by the consortium and supported by additional tests of the Joint Research Centre of the European Commission. An overview of results achieved up to now, given in this paper, is illustrating the latest scientific and technological advances. (author)
Research and development of supercritical-pressure water cooled reactors
International Nuclear Information System (INIS)
Full text: Supercritical water does not exhibit a change of phase. The water density decreases continuously with temperature. The heat is efficiently removed at the pseudo-critical temperature, which is approximately 385 deg. C at 25MPa. The low density fluid above this temperature is often called 'steam' and high density fluid below it is called 'water'. Supercritical-pressure water cooled reactor (SCWR) adopts the once-through coolant cycle with the 'water' as the reactor inlet and the 'steam' as the outlet. The 'steam' is directly fed to the turbines. The advantages are the compactness of the plant system due to the high specific enthalpy of supercritical fluid, the simplicity of the plant system without the recirculation system and dryers of BWRs and steam generators of PWRs and high thermal efficiency without the limit of the boiling temperature. Pressure vessel type SCWRs have been developed at the University of Tokyo since 1989 and is studied Japan, Europe and other countries. The University of Tokyo's version is called Super LWR and Super FR. The European version is called HPLWR (high performance light water reactor). Pressure tube type SCWR is studied in Canada and other countries. Roughly speaking, the reactor pressure vessel and the control rods of Super LWR and Super FR are similar to those of PWRs, the containment and safety system are to BWRs and balance of plant is to supercritical fossil-fired power plants (FPPs). LWRs were developed 50 years ago. Theis). LWRs were developed 50 years ago. Their successful implementation was based in part on experiences with subcritical fossil-fuel fired power (FPP) technologies at that time. The number of supercritical FPPs worldwide is larger than that of nuclear power plants. Considering the evolutionary history of boilers and the abundant experiences with supercritical FPP technologies, the supercritical pressure light water cooled reactor is the natural evolution of LWRs. Water cooled fast reactors require a tight fuel lattice. The once-through coolant cycle is compatible with the tight lattice core of water cooled fast reactors. The increase in the core pressure drop due to the tight lattice does not cause problems with pumping power and stability because of the low coolant flow rate of the once-through cycle and small difference of water densities between the 'steam' and the 'water' at the supercritical pressure. The plant system of the Super FR is the same as that of the Super LWR, a thermal reactor. Fast reactors do not need a moderator. Their power density is inevitably higher than that of thermal reactors. High power density is an advantage in economy. The Super FR has higher power density than the Super LWR. The Super LWR is expected to show better economy than LWRs due to the compactness, simplicity of the plant systems and high thermal efficiency. The guidelines of the Super LWR and Super FR concept development are the following. 1. Utilize supercritical FPP and LWR technologies as much as possible. 2. Minimize large scale developments of major components. 3. Pursue simplicity in design. The maximum temperature of the major components such as turbines, the reactor pressure vessel, main steam piping, reactor coolant pumps and control rod drives has been kept within the experiences of supercritical FPPs and LWRs. The concept of Super LWR and Super FR are developed based on numerical simulation at the University of Tokyo. The studies cover fuel and core design, plant control, start-up, stability, plant heat balance, and safety analysis. An advantage in safety is that depressurization cools the core in the once-through coolant cycle reactor such as Super LWR and Super FR. Thermal hydraulic experiments using 7 fuel rod bundles are carried out at Kyusyu University and JAEA. The measurement of critical flow at depressurization, condensation of supercritical steam and the critical heat flux near the critical pressure have been made at Kyusyu University. Austenitic stainless steels based on the experience of PNC1520 are tested as the cladding materials at JAEA. Therma
Water Towers, Pump Houses, and Mountain Streams: Students' Ideas about Watersheds
Daniel Shepardson
This study investigates students' ideas about watersheds and how these ideas change across grade level. A group of 95 students were each asked to draw a picture of a watershed and explain their drawings. The results revealed that, in general, students understand the concept of watersheds from a very limited scientific perspective. Sixth and some seventh grade students envisioned watersheds as a water storage facility or a facility that supplies water. Eighth and ninth grade students' ideas about a watershed focused on a mountainous stream. Older students also incorporated the hydrologic cycle, but rarely represented linkages between land and watercourses. For all students, humans do not appear to be a part of a watershed, but separate from it.
A water-cooled mirror system for synchrotron radiation
International Nuclear Information System (INIS)
This paper describes the design and performance of a directly-cooled soft x-ray mirror system which has been developed at Lawrence Berkeley Laboratory for synchrotron radiation beam lines in which mirror thermal distortion must be minimized for acceptable optical performance. Two similar mirror systems are being built: the first mirror has been installed and operated at the National Synchrotron Light Source on the X-17T mini-undulator beam line and will be moved to the permanent X-1 beam line when a new, more powerful undulator is installed there. The second system is being built for installation at the Stanford Synchrotron Radiation Laboratory on Beam Line VI, where the total absorbed power on the mirror may be as high as 2400 W with peak absorbed power density of 520 W/cm2. Direct cooling by convection is achieved using internal water channels in a brazed, dispersion-strengthened copper and OFHC copper substrate with a polished electroless-nickel surface. A simple kinematic linkage and flexural pivot mounting provide for mirror positioning about two rotational axes that coincide with the optical surface. Surface figure metrology, optical configurations, and tolerancing are also discussed. 11 refs., 8 figs
Tests of cooling water pumps at Dukovany nuclear power plant
International Nuclear Information System (INIS)
Tests were performed to examine the operating conditions of the 1600 BQDV cooling pumps of the main coolant circuit of unit 1 of the Dukovany nuclear power plant. For the pumps, the performance was tested in the permissible operating range, points were measured below this range and the guaranteed operating point was verified. Pump efficiency was calculated from the measured values. The discussion of the measurement of parameters has not yet been finished because the obtained values of the amount delivered and thus of the pump efficiency were not up to expectation in all detail. It was also found that for obtaining the guaranteed flow the pump impeller had to be opened to 5deg -5.5deg instead of the declared 3deg. Also tested were pump transients, including the start of the pump, its stop, the operation and failure of one of the two pumps. In these tests, pressures were also measured at the inlet and the outlet of the inner part of the TG 11 turbine condenser. It was shown that the time course and the pressure course of the processes were acceptable. In addition to these tests, pressure losses in the condenser and the cooling water flow through the feed pump electromotor cooler wre tested for the case of a failure of one of the two pumps. (E.S.)
Water cooling system for an air-breathing hypersonic test vehicle
Petley, Dennis H.; Dziedzic, William M.
This study provides concepts for hypersonic experimental scramjet test vehicles which have low cost and low risk. Cryogenic hydrogen is used as the fuel and coolant. Secondary water cooling systems were designed. Three concepts are shown: an all hydrogen cooling system, a secondary open loop water cooled system, and a secondary closed loop water cooled system. The open loop concept uses high pressure helium (15,000 psi) to drive water through the cooling system while maintaining the pressure in the water tank. The water flows through the turbine side of the turbopump to pump hydrogen fuel. The water is then allowed to vent. In the closed loop concept high pressure, room temperature, compressed liquid water is circulated. In flight water pressure is limited to 6000 psi by venting some of the water. Water is circulated through cooling channels via an ejector which uses high pressure gas to drive a water jet. The cooling systems are presented along with finite difference steady-state and transient analysis results. The results from this study indicate that water used as a secondary coolant can be designed to increase experimental test time, produce minimum venting of fluid and reduce overall development cost.
Status of advanced technology and design for water cooled reactors: Heavy water reactors
International Nuclear Information System (INIS)
In 1987 the IAEA established the International Working Group on Advanced Technologies for Water-Cooled Reactors (IWGATWR). Within the framework of the IWGATWR the IAEA Technical Report on Status of Advanced Technology and Design for Water Cooled Reactors, Part I: Light Water Reactors and Part II: Heavy Water Reactors, has been undertaken to document the major current activities and trends of technological improvement and development for future water reactors. Part I of the report dealing with Light Water Reactors (LWRs) was published in 1988 (IAEA-TECDOC-479). Part II of the report covers Heavy Water Reactors (HWRs) and has now been prepared. This report is based largely upon submissions from Member States. It has been supplemented by material from the presentations at the IAEA Technical Committee and Workshop on Progress in Heavy Water Reactor Design and Technology held in Montreal, Canada, December 6-9, 1988. It is hoped that this part of the report, containing the status of advanced heavy water reactor technology up to 1988 and ongoing development programmes will aid in disseminating information to Member States and in stimulating international cooperation. Refs, figs and tabs
Numerical simulation of supercritical water cooled reactor using lumped parameter model
International Nuclear Information System (INIS)
The concept of a nuclear reactor cooled by supercritical water is of current interest because of its potential to achieve higher thermal efficiency and a compact system design. In the present work, for a supercritical water cooled reactor, the variation of mean coolant temperature with respect to some important design parameters has been studied. A lumped parameter mathematical model has been used for numerical simulation, along with International Association for the Properties of Water and Steam equations of state for properties of supercritical water and a heat transfer correlation for supercritical water. This parametric study can be used for developing codes for numerical simulation and optimization of supercritical water cooled reactors. (author)
Scientific Electronic Library Online (English)
M.T.S., Lutterbach; F.P. de, Fran�a.
Full Text Available Brass coupons were installed in a bypass in an industrial cooling water that uses seawater. The metal samples were removed at 15, 30, 45, and 60-day intervals for quantitative and qualitative analyses of the microorganisms constituting the biofilm adhering to the metal surface. After 15 days of expo [...] sure, a biofilm had already been generated which contained aerobic and anaerobic microorganisms. The aerobic bacteria were the most stable in relation to quantity, followed by the fungi. Anaerobic microorganisms, as well as sulfate-reducing bacteria, were present at higher concentrations. Variations in sulfide contents were observed in the biofilm. Analysis by scanning electron microscopy revealed microalgae, bacteria, filaments, and corrosion products as constituents of the biofilm adhering to the surface of the metal. After the biofilms were scraped off the brass samples, evidence of corrosion was observed on the metal surface
Detecting and mitigating aging in component cooling water systems
International Nuclear Information System (INIS)
The time-dependent effects of aging on component cooling water (CCW) systems in nuclear power plants has been studied and documented as part of a research program sponsored by the US Nuclear Regulatory Commission. It was found that age related degradation leads to failures in the CCW system which can result in an increase in system unavailability, if not properly detected and mitigated. To identify effective methods of managing this degradation, information on inspection, monitoring, and maintenance practices currently available was obtained from various operating plants and reviewed. The findings were correlated with the most common aging mechanisms and failure modes and a compilation of aging detection and mitigation practices was formulated. This paper discusses the results of this work
Flow-induced vibration of component cooling water heat exchangers
International Nuclear Information System (INIS)
This paper presents an evaluation of flow-induced vibration problems of component cooling water heat exchangers in one of Taipower's nuclear power stations. Specifically, it describes flow-induced vibration phenomena, tests to identify the excitation mechanisms, measurement of response characteristics, analyses to predict tube response and wear, various design alterations, and modifications of the original design. Several unique features associated with the heat exchangers are demonstrated, including energy-trapping modes, existence of tube-support-plate (TSP)-inactive modes, and fluidelastic instability of TSP-active and -inactive modes. On the basis of this evaluation, the difficulties and future research needs for the evaluation of heat exchangers are identified. 11 refs., 19 figs., 3 tabs
Directory of Open Access Journals (Sweden)
M.T.S. Lutterbach
Full Text Available Brass coupons were installed in a bypass in an industrial cooling water that uses seawater. The metal samples were removed at 15, 30, 45, and 60-day intervals for quantitative and qualitative analyses of the microorganisms constituting the biofilm adhering to the metal surface. After 15 days of exposure, a biofilm had already been generated which contained aerobic and anaerobic microorganisms. The aerobic bacteria were the most stable in relation to quantity, followed by the fungi. Anaerobic microorganisms, as well as sulfate-reducing bacteria, were present at higher concentrations. Variations in sulfide contents were observed in the biofilm. Analysis by scanning electron microscopy revealed microalgae, bacteria, filaments, and corrosion products as constituents of the biofilm adhering to the surface of the metal. After the biofilms were scraped off the brass samples, evidence of corrosion was observed on the metal surface
Effect of Mixed Corrosion Inhibitors in Cooling Water System
Directory of Open Access Journals (Sweden)
Dina Raheem
Full Text Available The effect of mixed corrosion inhibitors in cooling system was evaluated by using carbon steel specimens and weight loss analysis. The carbon steel specimens immersed in mixture of sodium phosphate (Na2 HPO4 used as corrosion inhibitor and sodium glocunate (C6 H11 NaO7 as a scale dispersant at different concentrations (20,40, 60, 80 ppm and at different temperature (25,50,75 and 100�C for (1-5 days. The corrosion inhibitors efficiency was calculated by using uninhibited and inhibited water to give 98.1%. The result of these investigations indicate that the corrosion rate decreases with the increase the corrosion inhibitors concentration at 80 ppm and at 100�C for 5 days, (i.e, corrosion rate= 0.014gmd.
Research of a Supercritical Pressure Water Cooled Reactor in Korea
International Nuclear Information System (INIS)
In this paper the activities on the supercritical pressure water-cooled reactor (SCWR) in Korea are briefly introduced. Four projects on a SCWR are being conducted in Korea. Three of them are supported by the I-NERI program while one is by KAERI. Two of the I-NERI-supported projects concern suitable materials for supercritical pressure and temperature, and radiation environment. The other I-NERI-supported project surveys numerically and experimentally the proper turbulence modeling for the numerical calculation of heat transfer phenomena at a supercritical condition. Heat transfer at a supercritical condition is being studied at KAERI experimentally using carbon dioxide as a coolant. The test loop is to be completed by the end of 2004. (authors)
Material development for supercritical water-cooled reactors
Energy Technology Data Exchange (ETDEWEB)
Matsui, H.; Sato, Y. [Tohoku Univ., Institute for Materials Research (Japan); Saito, N.; Kano, F. [Power And Industrial Systems R and D Center, Toshiba Corporation, Yokohama (Japan); Ooshima, K. [Toshiba Corporation, System Design and Engineering Department, Yokohama, Kanagawa (Japan); Kaneda, J. [Materials Research Laboratory, Hitachi, Limited, Hitachi, Ibaraki (Japan); Moriya, K. [Power and Industrial Systems, Hitachi, Limited, Hitachi, Ibaraki (Japan); Ohtsuka, S. [Japan Atomic Energy Agency, Advanced Nuclear System R and D Directorate, Ibaraki (Japan); Oka, Y. [Tokyo Univ., Nuclear Engineering Research Lab. (Japan)
The material development project on supercritical water-cooled reactor (SCWR) launched in 2004 as an international nuclear research initiative project in Japan. This project consists of three sub-theme: 1) material/design compatibility, 2) irradiation properties, 3) complex effects of irradiation and supercritical water corrosion (SWC). In the first sub-theme, the test items, test conditions and criteria are determined through the survey on the requirement for the reactor core materials in terms of mechanical properties, phase stability, corrosion behavior, and supercritical corrosion (SCC) properties. In the second sub-theme, JMTR (Japan Materials Testing Reactor) and Experimental Fast Reactor JOYO were selected as irradiation test reactors considering their neutron flux, capable fluence and irradiation temperature. Post irradiation examination (PIE) is conducted for microstructure, mechanical strength, hardness and creep deformation. In the third sub-theme, general corrosion tests are conducted in supercritical water after the neutron irradiation. Besides the neutron irradiation tests, material evaluation tests are being carried out using un-irradiated specimens to understand basic properties of test materials in the temperature range of SCWR. This paper describes the framework and the interim results until the third year of the 4-year program. (authors)
Plutonium breeding of light water cooled fast reactors
International Nuclear Information System (INIS)
Light water cooled fast reactor with new fuel assemblies (FA) has been studied for high breeding of fissile plutonium. It achieves fissile plutonium surviving ratio (FPSR) of 1.342 (discharge/loading), 1.013 end and beginning of equilibrium cycle (EOEC/BOEC), and compound system doubling time (CSDT) of 95.9 years at the average coolant density of pressurized water reactor (PWR). It is further improved for reduced moderation boiling water reactor (BWR) (RMWR) coolant density. Fissile plutonium surviving ratio reaches 1.397 (discharge/loading), 1.030 (EOEC/BOEC) and CSDT is 37 years. The present study has shown the possibility of breeding at the PWR coolant density and meeting the growth rate of energy demand of advanced countries at the RMWR and Super FR coolant density for the first time. The new FA consist of closely packed fuel rods. The integrity of welding of fuel rods at the top and bottom ends is maintained as the conventional fuel rods. The coolant to fuel volume fraction is reduced to 0.085, one-sixth of that of RMWR. The volume fraction remains unchanged with the diameter of the fuel rod. The thermal hydraulic design of the cores remains for the future study. (author)
Material development for supercritical water-cooled reactors
International Nuclear Information System (INIS)
The material development project on supercritical water-cooled reactor (SCWR) launched in 2004 as an international nuclear research initiative project in Japan. This project consists of three sub-theme: 1) material/design compatibility, 2) irradiation properties, 3) complex effects of irradiation and supercritical water corrosion (SWC). In the first sub-theme, the test items, test conditions and criteria are determined through the survey on the requirement for the reactor core materials in terms of mechanical properties, phase stability, corrosion behavior, and supercritical corrosion (SCC) properties. In the second sub-theme, JMTR (Japan Materials Testing Reactor) and Experimental Fast Reactor JOYO were selected as irradiation test reactors considering their neutron flux, capable fluence and irradiation temperature. Post irradiation examination (PIE) is conducted for microstructure, mechanical strength, hardness and creep deformation. In the third sub-theme, general corrosion tests are conducted in supercritical water after the neutron irradiation. Besides the neutron irradiation tests, material evaluation tests are being carried out using un-irradiated specimens to understand basic properties of test materials in the temperature range of SCWR. This paper describes the framework and the interim results until the third year of the 4-year program. (authors)
Corrosion Prevention of the Generator Stator Hollow Copper Conductor and Water Quality Adjustment of Its Internal Cooling Water
Directory of Open Access Journals (Sweden)
Xuenong XIE
Full Text Available On the basis of expounding the corrosion mechanism of the stator hollow copper conductor in the water-cooling generator, methods of preventing corrosion of the stator hollow copper conductor in the wa-ter-cooling generator through adjusting water quality of its cooling water have been proposed. For internal water cooling systems which are airtight, the corrosion of the hollow copper conductor can be prevented through keeping foreign oxygen and carbon dioxide from entering the system, and the amount of oxygen in the internal water can be lowered by blowing high purity nitrogen. For systems not airtight, the corrosion of the hollow copper conductor can be inhibited through lowering the amount of oxygen to some extent by sealing and increasing pH value by processing part of cooling water with bypass small flow sodium-type mix-bed.
Status of advanced technology and design for water cooled reactors: Light water reactors
International Nuclear Information System (INIS)
Water reactors represent a high level of performance and safety. They are mature technology and they will undoubtedly continue to be the main stream of nuclear power. There are substantial technological development programmes in Member States for further improving the technology and for the development of new concepts in water reactors. Therefore the establishment of an international forum for the exchange of information and stimulation of international co-operation in this field has emerged. In 1987 the IAEA established the International Working Group on Advanced Technologies for Water-Cooled Reactors (IWGATWR). Within the framework of IWGATWR the IAEA Technical Report on Status of Advanced Technology and Design for Water Cooled Reactors, Part I: Light Water Reactors and Part II: Heavy Water Reactors has been undertaken to document the major current activities and different trends of technological improvements and developments for future water reactors. Part I of the report dealing with LWRs has now been prepared and is based mainly on submissions from Member States. It is hoped that this part of the report, containing the status of advanced light water reactor design and technology of the year 1987 and early 1988 will be useful for disseminating information to Agency Member States and for stimulating international cooperation in this subject area. 93 refs, figs and tabs
Advanced applications of water cooled nuclear power plants
International Nuclear Information System (INIS)
By August 2007, there were 438 nuclear power plants (NPPs) in operation worldwide, with a total capacity of 371.7 GW(e). Further, 31 units, totaling 24.1 GW(e), were under construction. During 2006 nuclear power produced 2659.7 billion kWh of electricity, which was 15.2% of the world's total. The vast majority of these plants use water-cooled reactors. Based on information provided by its Member States, the IAEA projects that nuclear power will grow significantly, producing between 2760 and 2810 billion kWh annually by 2010, between 3120 and 3840 billion kWh annually by 2020, and between 3325 and 5040 billion kWh annually by 2030. There are several reasons for these rising expectations for nuclear power: - Nuclear power's lengthening experience and good performance: The industry now has more than 12 000 reactor years of experience, and the global average nuclear plant availability during 2006 reached 83%; - Growing energy needs: All forecasts project increases in world energy demand, especially as population and economic productivity grow. The strategies are country dependent, but usually involve a mix of energy sources; - Interest in advanced applications of nuclear energy, such as seawater desalination, steam for heavy oil recovery and heat and electricity for hydrogen production; - Environmental concerns and constraints: The Kyoto Protocol has been in force since February 2005, and for many countries (most OECD countries, the Russian Federation, the Baltics and some countries of the Former Soviet Union and Eastern Europe) greenhouse gas emission limits are imposed; - Security of energy supply is a national priority in essentially every country; and - Nuclear power is economically competitive and provides stability of electricity price. In the near term most new nuclear plants will be evolutionary water cooled reactors (Light Water Reactors (LWRs) and Heavy Water Reactors (HWRs), often pursuing economies of scale. In the longer term, innovative designs that promise shorter construction times and lower capital costs could help to promote a new era of nuclear power. About one-fifth of the world's energy consumption is used for electricity generation. Most of the world's energy consumption is for heat and transportation. Nuclear energy has considerable potential to penetrate these energy sectors now served by fossil fuels that are characterized by price volatility and finite supply. Advanced applications of nuclear energy include seawater desalination, district heating, heat for industrial processes, and electricity and heat for hydrogen production. In addition, since nuclear electricity is generally produced in a base load mode at stable prices, there is considerable near-term potential for nuclear power to contribute to the transportation sector as a carbon-free source of electricity for charging electric and plug-in hybrid vehicles. This collaborative assessment was recommended by the IAEA Nuclear Energy Department's Technical Working Groups on Advanced Technologies for LWRs and HWRs (the TWG-LWR and TWG-HWR). The objective has been to identify opportunities and challenges for water cooled reactors to capture a substantial share of the above mentioned advanced applications. For each application, the opportunities, market context, challenges and potential solutions are addressed
Studies on corrosion inhibitors for the cooling water system at the Heavy Water Project, Kota
International Nuclear Information System (INIS)
The Heavy Water Project at Kota uses the water from the Rana Pratap Sagar Lake as coolant in the open recirculation system. In order to find suitable corrosion inhibitors for the above system, a series of laboratory experiments on corrosion inhibitors were carried out using the constructional materials of the cooling water system and a number of proprietary formulations and the results are tabulated. From the data thus generated through various laboratory experiments, the most useful ones have been recommended for application in practice. (author)
Study of Cooling Characteristic of The Containment APWR Model Using Laminar Subcooled Water Film
International Nuclear Information System (INIS)
One of mechanism utilized by the next-generation pressurized water reactor for cooling its containment passively is gravitationally falling water spray cooling. This paper focuses on the characteristic study using Fluent 5/6 program for the case of the containment outer wall cooling by laminar sub-cooled water film. The cooling system characteristics which will be discussed consist of water film thickness and temperature on all parts of the containment wall as well as the effect of water spray volume flow rate on the water film thickness and convection heat transfer capability from the containment wall to the film bulk. In addition, some kinds of non dimensional numbers involved in the film heat transfer correlation will be presented in this paper. (author)
Cloud Super-Cooled Liquid Water Estimation from Satellite Data
Roskovensky, J. K.; Ivey, M.; Porch, W.; Beavis, N.; Herrman, R.
An automated algorithm for estimating cloud super-cooled liquid water (SLW) from satellite data was developed to perform cloud surveys for assessing potential precipitation enhancement. The algorithm produces spatial cloud SLW column distributions by utilizing many of the Moderate Resolution Imaging Spectroradiometer (MODIS) derived cloud products in addition to parameterizations developed to estimate vertical cloud thickness and fractional cloud liquid water content. Vertically derived cloud SLW is integrated to produce column totals. Sensitivity studies identified differences up to 30% in SLW content from individual changes in the minimum cloud optical depth threshold, vertical cloud thickness estimation, moist adiabatic lapse rate, and cloud liquid fraction parameterization constants. Corrections to MODIS cloud water path artifacts also reduced the estimated SLW content by 10% to 50%. Validation of the cloud base height and temperature estimates and derived total column SLW has begun using ground data from the Atmospheric Radiation Measurement North Slope Alaska site and CloudSat radar derived cloud products. Results thus far indicate that the algorithm may underestimate important cloud properties such as cloud thickness and cloud liquid water content which, in turn, may lead to an underestimation of cloud SLW. Comparisons of the algorithm�s vertical estimates of cloud SLW to aircraft data taken during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) in northern Alaska yield very good results. National Center for Environmental Prediction reanalysis data was sampled along with annual MODIS datasets in both dry and wet years over the state of New Mexico to identify specific environmental indicators. Although cloud coverage was similar between the two periods, cloud SLW was found to be 60% greater and the number of days in which the 500 mb level wind was predominantly westerly increased by 12% during the wet year. The parameters with the highest correlation to cloud SLW were the 700 mb to the 500 mb level relative humidity.
Integration of Small Solar Tower Systems Into Distributed Power Islands
International Nuclear Information System (INIS)
One of the short-term priorities for renewable energies in Europe is their integration for local power supply into communities and energy islands (blocks of buildings, new neighborhoods in residential areas, shopping centers, hospitals, recreational areas, eco-parks, small rural areas or isolated ones such as islands or mountain communities). Following this strategy, the integration of small tower fields into so-called MIUS (Modular Integrated Utility Systems) is proposed. This application strongly influences field concepts leading to modular multi-tower systems able to more closely track demand, meet reliability requirements with fewer megawatts of installed power and spread construction costs over time after output has begun. In addition, integration into single-cycle high-efficiency gas turbines plus waste-heat applications clearly increments the solar share. The chief questions are whether solar towers can be redesigned for such distributed markets and the keys to their feasibility. This paper includes the design and performance analysis of a 1.36-MW plant and integration in the MIUS system, as well as the expected cost of electricity and a sensitivity analysis of the small tower plant's performance with design parameters like heliostats configuration and tower height. A practical application is analyzed for a shopping center with 85% power demand during day-time by using a hybrid solar tower and a gas turbine producing electricity and waste heat for hot water and heating and cooling of spaces. The operation mode proposed is covering night demand with power from the grid and solar-gas power island mode during 14 hours daytime with a maximum power production of 1.36 MW. (Author) 26 refs
Experience with fuel for water-cooled power reactors
International Nuclear Information System (INIS)
Because of its background and its current activities in design, manufacturing and the provision of services, KWU is in a unique position to cover the whole spectrum of fuel for water-cooled power reactors. In accordance with the early nuclear programmes of the Federal Republic of Germany development work started with fuel for heavy water reactors which required low parasitic design and materials. On the basis of that experience, the following step to PWR fuel was characterized by the use of Zircaloy for the fuel rod cladding from the very beginning. The first BWRs in the Federal Republic of Germany also used Zircaloy. The recycling of plutonium was investigated and demonstrated in all these thermal reactor systems in addition to the standard use of natural and enriched uranium. The paper presents KWU's manufacturing and performance experience and the development work aimed at increased plant power, increased burnup, improved economy and reliability. This evolution was accomplished by continuous feed-back from large experimental and surveillance activities to the design work and the manufacturing processes. In this respect the existence of an experienced service organization plays an important role. Close co-operation with KWU's customers has been very important. Technology transfer in the field of the nuclear fuel cycle is one prominent example of co-operation aimed at establishing domestic capacity of partner countries. (author)or)
Evaluation of a Design Concept for the Combined Air-water Passive Cooling PAFS+
International Nuclear Information System (INIS)
The APR+ system provides the Passive Auxiliary Feed-water System (PAFS) for the passive cooling capability. However, the current design requirement for working time for the PAFS is about 8 hours only. Thus, current working time of PAFS can not meet the required 72 hours cooling capability for the long term SBO situation. To meet the 72 hours cooling, the pool capacity should be almost 3?4 times larger than that of current water cooling tank. In order to continue the PAFS operation for 72 hours, a new passive air-water combined cooling system is proposed. This paper provides the feasibility study on the combined passive air-water cooling system. Figure 1 and 2 show the conceptual difference of the PAFS and combined passive air-water cooling system, respectively. Simple performance evaluation of the passive air cooling heat exchanger has been conducted by the MARS calculation. For the postulated FLB scenario, 4800 heat exchanger tubes and 5 m/s air velocity are not sufficient to sustain the PCCT pool level for 72 hour cooling. Further works on the system design and performance enhancing plan are required to fulfill the 72 hours long term passive cooling
The Preliminary Research of Sea Water District Heating and Cooling for Tallinn Coastal Area
Allan Hani; Teet-Andrus Koiv
This paper describes possibilities to utilize sea water for district heating and cooling purposes in Tallinn costal area. The sea water temperature profiles and suitability of heating and cooling generation are studied for continental climatic conditions. The district network study bases on 21 buildings located near to the Gulf of Finland. Industrial reversible heat pump technology is selected to cover heating and cooling loads for the new buildings. Combination of existing district heating a...
Behavior and removal of radionuclides generated in the cooling water of a proton accelerator
International Nuclear Information System (INIS)
Radionuclides such as 7Be, 60Co, 65Zn, and 54Mn are present in the magnet cooling water of a proton accelerator. These nuclides may be dissolved or bound to colloids and pass through micrometric filters below 100 nm. A cooling water purification strategy is discussed. The most efficient procedure uses a cation exchanger in H+ form
40 CFR 63.1086 - How must I monitor for leaks to cooling water?
...such that, based on the rate of cooling water at the...test method being used, a leak of 3.06 kg/hr or greater...that the cooling water flow rate is 51,031 liters per minute or less so that a leak of 3.06 kg/hr can...
Cooling of Water in a Flask: Convection Currents in a Fluid with a Density Maximum
Velasco, S.; White, J. A.; Roman, F. L.
The effect of density inversion on the convective flow of water in a spherical glass flask cooled with the help of an ice-water bath is shown. The experiment was carried out by temperature measurements (cooling curves) taken at three different heights along the vertical diameter of the flask. Flows inside the flask are visualized by seeding the�
Biological effects from discharge of cooling water from thermal power plants
International Nuclear Information System (INIS)
Results are reported for a Danish project on biological effects from discharge of cooling water from thermal power plants. The purpose of the project was to provide an up-to-date knowledge of biological effects of cooling water discharge and of organization and evaluation of recipient investigations in planned and established areas. (BP)
Changes to the NRAD cooling water systems for proposed 1 MW operations
International Nuclear Information System (INIS)
In order to decrease exposure times, the increase of the reactor power level to 1 MW is considered. This increase in the reactor power level necessitates major engineering and design changes to the primary cooling water system, demineralizer system, and the secondary cooling water system, described in the document
Innovative water cooled reactor concepts - Small and medium reactors
International Nuclear Information System (INIS)
Full text: Innovative water-cooled Small and Medium Reactors (SMRs) will play an essential role in meeting global energy needs. Based on well-known and well-tested water cooled reactor technology, this type of SMR can be licensed within the existing regulatory framework and have a ready supply of fuel and component manufacturers. As a result, water-cooled SMRs represent a near-term nuclear power solution. Excellent overviews of numerous SMRs, including water cooled concepts such as the KLT-40S, CAREM, SMART, IRIS, SCOR, AHWR, MARS, and MASLWR have been provided by the IAEA. The advantages of SMRs are well known. Their smaller sizes make them suitable for a greater number of power grids and applications. This fact, coupled to their lower capital costs, yield a state-of-the-art nuclear energy solution with the potential of achieving a much greater market penetration than larger plants. SMR designs that utilize factory built components that can be shipped to a site by rail, truck or barge offer shorter construction times and greater cost certainty hence reducing financial risk. Many SMRs eliminate the choke points for the supply of large components such as reactor vessel forgings and large turbines. Their reduced core inventories present a smaller fission product source term which permits a greatly reduced emergency planning zone. This would allow SMRs to be sited in the proximity of large population centers while reducing power line losses. Some SMRs propose longer coreline losses. Some SMRs propose longer core lives which significantly reduce plant down time. Among the water cooled SMRs, there exists a special class of reactors that are both modular and scalable. The fundamental concept is that of constructing a central power station comprised of multiple small power reactors. As regional power demand increases, additional modules can be added in the most economic manner to meet any size power need. Of particular interest is the NuScale Multi-Module Power Plant; a design that has evolved from the MASLWR concept developed at Oregon State University. This design employs both the economy of scale through the use of multiple modules and the economy of small through reduced size and simplification to offer significant operational advantages while being financially competitive with the large reactors. The NuScale plant design has been guided by a comprehensive set of customer utility requirements and informed by U.S. expert panels on reactor safety and data and analyses using state-of-the-art computer codes benchmarked against a 1/3-scale full-pressure, full temperature integral system test facility at Oregon State University. The unique characteristics of a NuScale multi-module plant are the topic of discussion for this paper. The NuScale Nuclear Steam Supply System (NSSS) is very compact. It is enclosed in a containment that is only 18.3 m (60 ft) long by approximately 4.6 m (15 feet) in diameter. It includes the reactor pressure vessel which is 13.7m (45 ft) long by 2.7 m (9 ft) in diameter which contains the nuclear core, a helical coil steam generator, and a pressurizer. The nuclear core consists of an array of roughly half-height LWR fuel assemblies and control rod clusters at standard enrichments. The helical coil steam generator consists of two independent sets of tube bundles with separate feedwater inlet and steam outlet lines. Feedwater is pumped into the tubes where it boils to generate superheated steam. A set of pressurizer heaters is located in the upper head of the vessel to provide pressure control. Primary flow through the nuclear core is driven by natural circulation. Each module is independently connected to a small steam turbine generator set capable of producing a net power of 45 MW(e). The base platform for a NuScale plant consists of 12 modules capable of producing a total power of 540 MW(e). That is, one to twelve modules can be added to the base plant platform without the need for additional on-site construction. A multi-module central power station has many advantages. It eliminates single-shaft risk
Analysis on small long life reactor using thorium fuel for water cooled and metal cooled reactor types
International Nuclear Information System (INIS)
Long-life reactor operation can be adopted for some special purposes which have been proposed by IAEA as the small and medium reactor (SMR) program. Thermal reactor and fast reactor types can be used for SMR and in addition to that program the utilization of thorium fuel as one of the candidate as a 'partner' fuel with uranium fuel which can be considered for optimizing the nuclear fuel utilization as well as recycling spent fuel. Fissile U-233 as the main fissile material for thorium fuel shows higher eta-value for wider energy range compared with other fissile materials of U-235 and Pu-239. However, it less than Pu-239 for fast energy region, but it still shows high eta-value. This eta-value gives the reactor has higher capability for obtaining breeding condition or high conversion capability. In the present study, the comparative analysis on small long life reactor fueled by thorium for different reactor types (water cooled and metal cooled reactor types). Light water and heavy water have been used as representative of water-cooled reactor types, and for liquid metal-cooled reactor types, sodium-cooled and lead-bismuth-cooled have been adopted. Core blanket arrangement as general design configuration, has been adopted which consist of inner blanket region fueled by thorium oxide, and two core regions (inner and out regions) fueled by fissile U-233 and thorium oxide with different percentages of fissile content. SRAC-CITATION and JENDL-33 have been used as core optimization analysis and nuclear data library for this analysis. Reactor operation time can reaches more than 10 years operation without refueling and shuffling for different reactor types and several power outputs. As can be expected, liquid metal cooled reactor types can be used more effective for obtaining long life reactor with higher burnup, higher power density, higher breeding capability and lower excess reactivity compared with water-cooled reactors. Water cooled obtains long life core operation for relatively higher excess reactivity at the beginning of operation and it reduces along the core operation time. The effect of internal blanket region of liquid metal cooled reactor types has more significant effect for reducing excess reactivity at the beginning of operation and for increasing fissile production capability than water-cooled reactor. Void reactivity change during reactor operation of all reactor type cases has been investigated for several voided fraction conditions. It shows that all reactor types obtain negative void reactivity along the reactor operation time and higher voided fraction gives more negative void reactivity coefficient at the beginning of operation and it becomes less negative after 1 year operation. Thorium based reactor with different water cooled and liquid metal cooled types, can be used for obtaining long life reactor and negative void reactivity coefficient during reactor operation. (author)
North Atlantic Deep Water cools the southern hemisphere
Crowley, Thomas J.
A standard explanation for coupling climate variations in the northern and southern hemispheres involves fluctuations in North Atlantic Deep Water (NADW) production. However, I suggest that the "NADW-Antarctic" connection may work opposite to that conjectured by many investigators; that is, when NADW production rates are high, southern hemisphere temperatures decrease rather than increase. The revised interpretation is consistent with observations and ocean modeling studies which demonstrate that, although upwelling of relatively warm NADW water around Antarctica promotes sea ice meltback, a second and more important negative feedback is also operating. In order to conserve volume, southward export of NADW across the equator is accompanied by import of an equivalent volume of considerably warmer water from shallower oceanic layers in the South Atlantic. The southern hemisphere loses heat as a result of this exchange. The hemispherically averaged net heat loss may be as high as 4 W/m�, an amount comparable to a CO2 doubling. It is suggested that this more comprehensive view of the role of NADW may explain both decadal-scale variations in South Atlantic sea surface temperatures in this century and two significant problems in Pleistocene climatology: why southern hemisphere temperatures decreased before CO2 levels decreased at the end of the last interglacial and why southern hemisphere temperature changes precede changes in northern hemisphere ice volume. It is shown that when NADW production was reinitiated during the last interglacial (120,000 B.P.), high-latitude southern hemisphere temperatures decreased. The estimated magnitude of altered southern hemisphere heat export is comparable to the ice-age CO2 signal and may be able to account for the observed cooling even when CO2 levels were high. When cast into a frequency domain framework, this interpretation may also help explain why southern hemisphere temperatures lead global ice volume changes.
Mitigation of hydrogen hazards in water cooled power reactors
International Nuclear Information System (INIS)
Past considerations of hydrogen generated in containment buildings have tended to focus attention on design basis accidents (DBAs) where the extent of the in-core metal-water reaction is limited at low values by the operation of the emergency core cooling systems (ECCS). The radiolysis of water in the core and in the containment sump, together with the possible corrosion of metals and paints in the containment, are all relatively slow processes. Therefore, in DBAs the time scale involved for the generation of hydrogen allows sufficient time for initiation of measures to control the amount of hydrogen in the containment atmosphere and to prevent any burning. Provisions have been made in most plants to keep the local hydrogen concentration below its flammability limit (4% of volume) by means of mixing devices and thermal recombiners. Severe accidents, involving large scale core degradation and possibly even core concrete interactions, raise the possibility of hydrogen release rates greatly exceeding the capacity of conventional DBA hydrogen control measures. The accident at Three Mile Island illustrated the potential of unmitigated hydrogen accumulation to escalate the potential consequences of a severe accident. In a severe accident scenario, local high hydrogen concentrations can be reached in a short time, leading to flammable gas mixtures in containment. Another possibility is that local high steam concentrations will initially create an inert atmosphere and prevent burning for a limited time. While such temporary inerting provides additional time for mixing (dilution) of the hydrogen with containment air, depending on the quantity of hydrogen released, it prevents early intervention by deliberate ignition and sets up conditions for more severe combustion hazards after steam condensation eventually occurs, e.g., by spray initiation or the long term cooling down of the containment atmosphere. As the foregoing example indicates, analysis of the hydrogen threat in post-accident containments is complex and highly plant- and scenario-specific. Many aspects must be considered in analysis of a hydrogen threat: accident sequences, hydrogen production rates, atmosphere thermal hydraulics, mixing processes, combustion phenomena, accident management strategies and mitigation hardware performance. Research activities on these topics have been continuing in several countries for the past two decades. This report summarizes current concepts for hydrogen mitigation in containments, concentrating primarily on measures that are already being implemented or those that show promise in the near future for hydrogen mitigation in severe accidents
Directory of Open Access Journals (Sweden)
Tonye. K. Jack
Full Text Available A quick evaluation approach to internal combustion (IC engine�s radiator cooling system analysis is presented. A computer program in Microsoft Excel TM is developed to assist in the calculations and analysis of engine cooling parameters such as fluid flow rate, effective cooling surface area, coolant passage tubes, and rate of heat dissipation when the density and specific heat at constant pressure vary due to the changing temperature. Derived curve-fitted correlations allow for proper estimates of fluid physical properties. Selection and application of a conservative heat transfer coefficient relationship based on the Nusselt relation, allows for determining an effective heat transfer area, taking into consideration the inter-relationships of all applicable parameters in the heat flow area. A method for estimating the number of tubes in the radiator for proper coolant circulation is shown. The positive side of using Water/ethylene-glycol mixture versus pure water used as coolant is discussed through a numerical example.
Water mist effect on heat transfer coefficient in cooling of casting die
Directory of Open Access Journals (Sweden)
R. W?adysiak
Full Text Available This project is showing investigation results of heat transfer process between cast iron die and environment during cooling of die in the temperature range 600�100 C with compressed air, spray water and water mist streamed under pressure 0.35 0.45 MPa in air jet0.3 0.4 MPa .At the paper are shown results of cooling die�s flat wall using open cooling system. The temperature gradient was presented at die�s wallthickness and calculated thermal curve for cooling surface. The calculation results of heat transfer coefficient ? were presented between die and researched cooling factors and also mathematical models of ? coefficient depending on surface temperature. Revealed that coefficient ? has the biggest value�s range for die cooling with water mist under pressure 0.3/0.35 MPa.
Cooling systems addendum: capital and total generating cost studies
International Nuclear Information System (INIS)
These studies present the capital and total generating costs for alternate cooling systems designed for six power plants--1200 MWe (pressurized water reactor, boiling water reactor, high sulfur coal-fired, low sulfur coal-fired) plants and 800 MWe (low-sulfur coal-fired and high-sulfur coal-fired) plants. In these base-capital cost studies, all of the plants are designed using mechanical-draft evaporate towers. Alternate cooling systems evaluated include: once-through, fan-assisted natural-draft towers, and natural-draft towers. These alternative cooling systems represent viable designs from both an economic and engineering standpoint. The estimated total base construction costs for the six plants incorporating the alternate cooling systems are summarized. Capital cost and fuel cost vary with each cooling system as compared to the base case; i.e., mechanical-draft evaporative towers. The once-through cooling systems have the lowest capital cost of the alternate systems evaluated
District cool water distribution; Reseau urbain et distribution d`eau glacee
Energy Technology Data Exchange (ETDEWEB)
Schabaillie, D. [Ste Climespace (France)
The city of Paris has developed several district cool water distribution networks (Climespace) for air conditioning purposes, one in the Halles district (central Paris) linked with the Louvre museum, one in the Opera district (with large department stores) and one in the east of paris (Bercy). Each of these networks has a cool water production plant, the one at the Halles producing also hot water and safety electric power. The characteristics of the equipment (heat pumps, refrigerating machinery, storage...) are described. The pipes are laid in the city sewage network, and the cool carrier is water. The various networks are centrally supervised at the Halles center
Detailed Design of Cooling Water System for Cold Neutron Source in HANARO
Energy Technology Data Exchange (ETDEWEB)
Kim, Bong Soo; Choi, Jung Woon; Kim, Y. K.; Wu, S. I.; Lee, Y. S
To make cold neutron, a cryogenic refrigerator is necessary to transform moderator into cryogenic state so, thermal neutron is changed into cold neutron through heat transfer with moderator. A cryogenic refrigerator mainly consists of two apparatus, a helium compressor and a cold box which needs supply of cooling water. Therefore, cooling water system is essential to operate of cryogenic refrigerator normally. This report is mainly focused on the detailed design of the cooling water system for the HANARO cold neutron source, and describes design requirement, calculation, specification of equipment and water treatment method.
Detailed Design of Cooling Water System for Cold Neutron Source in HANARO
International Nuclear Information System (INIS)
To make cold neutron, a cryogenic refrigerator is necessary to transform moderator into cryogenic state so, thermal neutron is changed into cold neutron through heat transfer with moderator. A cryogenic refrigerator mainly consists of two apparatus, a helium compressor and a cold box which needs supply of cooling water. Therefore, cooling water system is essential to operate of cryogenic refrigerator normally. This report is mainly focused on the detailed design of the cooling water system for the HANARO cold neutron source, and describes design requirement, calculation, specification of equipment and water treatment method
Scale controlling programme at Heavy Water Plant, Manuguru cooling water system
International Nuclear Information System (INIS)
Sulphuric acid and scale inhibiting chemicals such as sodium hexa meta phosphate (SHMP), hydroxy ethilidine diphosphonate (HEDP) and polyacrylate were used to treat the cooling water system of Heavy Water Plant, Manuguru. Effectiveness ratio of formulation and its constituents were studied for their inhibition of CaSO4 and CaCO3. Percentage inhibition of scale forming compounds such as CaSO4 and CaCO3 were also studied at different concentrations of formulation. (author). 4 refs., 7 figs., 3 tabs
Hydrogen in water-cooled nuclear power reactors
International Nuclear Information System (INIS)
The Commission of the European Community (CEC) and the International Atomic Energy Agency (IAEA) decided in 1989 to update the state of the art concerning hydrogen in water cooled nuclear power reactors by commissioning a report which would review, all the available information to-date and make recommendations for the future. This joint report was prepared by committees formed by the IAEA and by the CEC. The aim of this report is to review the current understanding on the areas in which the research on hydrogen in LWR is conventionally presented, taking into account the results of the latest reported research developments. The main reactions through which hydrogen is produced are assessed together with their timings. An estimation of the amount of hydrogen produced by each reaction is given, in order to reckon their relative contribution to the hazard. An overview is then given of the state of knowledge of the most important phenomena taking place during its transport from the place of production and the phenomena which control the hydrogen combustion and the consequences of combustion under various conditions. Specific research work is recommended in each sector of the presented phenomena. The last topics reviewed in this report are the hydrogen detection and the prevent/mitigation of pressure and temperature loads on containment structures and structures and safety related equipment caused by hydrogen combustion
State waste discharge permit application: 400 Area secondary cooling water
International Nuclear Information System (INIS)
This document constitutes the Washington Administrative Code 173-216 State Waste Discharge Permit Application that serves as interim compliance as required by the Consent Order DE 91NM-177, for the 400 Area Secondary Cooling Water stream. As part of the Hanford Federal Facility Agreement and Consent Order negotiations, the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect groundwater would be subject to permitting under the structure of Chapter 173-216 (or 173-218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permitting Program. As a result of this decision, the Washington State Department of Ecology and the US Department of Energy, Richland Operations Office entered in to Consent Order DE 91NM-177. The Consent Order DE 91NM-177 requires a series of permitting activities for liquid effluent discharges
Stability analysis of a heated channel cooled by supercritical water
International Nuclear Information System (INIS)
A simple model to study thermal-hydraulic stability of a heated cannel under supercritical conditions is presented. Single cannel stability analysis for the SCWR (Supercritical Water Cooled Reactor) design was performed. The drastic change of fluid density in the reactor core of a SCWR may induce DWO (Density Wave Oscillations) similar to those observed in BWRs. Due to the similarities between subcritical and supercritical systems we may treat the supercritical fluid as a pseudo two-phase system. Thus, we may extend the modeling approach often used for boiling flow stability analysis to supercritical pressure operation conditions. The model developed in this work take into account three regions: a heavy fluid region, similar to an incompressible liquid; a zone where a heavy fluid and a light fluid coexist, similar to two-phase mixture; and a light fluid region which behaves like superheated steam. It was used the homogeneous equilibrium model (HEM) for the pseudo boiling zone, and the ideal gas model for the pseudo superheated steam zone. System stability maps were obtained using linear stability analysis in the frequency domain. Two possible instability mechanisms are observed: DWO and excursive Ledinegg instabilities. Also, a sensitivity analysis showed that frictions in pseudo superheated steam zone, together with acceleration effect, are the most destabilizing effects. On the other hand, frictions in pseudo liquid zone are the most important stabilizing effect.
Thermohydraulics of emergency core cooling in light water reactors
International Nuclear Information System (INIS)
This report, by a group of experts of the OECD-NEA Committee on the Safety of Nuclear Installations, reviews the current state-of-knowledge in the field of emergency core cooling (ECC) for design-basis, loss-of-coolant accidents (LOCA) and core uncover transients in pressurized- and boiling-water reactors. An overview of the LOCA scenarios and ECC phenomenology is provided for each type of reactor, together with a brief description of their ECC systems. Separate-effects and integral-test facilities, which contribute to understanding and assessing the phenomenology, are reviewed together with similarity and scaling compromises. All relevant LOCA phenomena are then brought together in the form of tables. Each phenomenon is weighted in terms of its importance to the course of a LOCA, and appraised for the adequacy of its data base and analytical modelling. This qualitative procedure focusses attention on the modelling requirements of dominant LOCA phenomena and the current capabilities of the two-fluid models in two-phase flows. This leads into the key issue with ECC: quantitative code assessment and the application of system codes to predict with a well defined uncertainty the behaviour of a nuclear power plant. This issue, the methodologies being developed for code assessment and the question of how good is good enough are discussed in detail. Some general conclusions and recommendations for future research activities are provided
Accident analysis of heavy water cooled thorium breeder reactor
Yulianti, Yanti; Su'ud, Zaki; Takaki, Naoyuki
Thorium has lately attracted considerable attention because it is accumulating as a by-product of large scale rare earth mining. The objective of research is to analyze transient behavior of a heavy water cooled thorium breeder that is designed by Tokai University and Tokyo Institute of Technology. That is oxide fueled, PWR type reactor with heavy water as primary coolant. An example of the optimized core has relatively small moderator to fuel volume ratio (MFR) of 0.6 and the characteristics of the core are burn-up of 67 GWd/t, breeding ratio of 1.08, burn-up reactivity loss during cycles of factor. The best expression for the neutron distribution is the Boltzmann transport equation. However, solving this equation is very difficult so that the space-time diffusion equation is commonly used. Usually, space-time diffusion equation is solved by employing a point kinetics approach. However, this approach is less accurate for a spatially heterogeneous nuclear reactor and the nuclear reactor with quite large reactivity input. Direct method is therefore used to solve space-time diffusion equation which consider spatial factor in detail during nuclear reactor accident simulation. Set of equations that obtained from full implicit finite-difference method is solved by using iterative methods. The indication of UTOP accident is decreasing macroscopic absorption cross-section that results large external reactivity, and ULOF accident is indicated by decreasing coolant flow. The power reactor has a peak value before reactor has new balance condition. The analysis showed that temperatures of fuel and claddings during accident are still below limitations which are in secure condition.
Water mist effect on heat transfer coefficient in cooling of casting die
This project is showing investigation results of heat transfer process between cast iron die and environment during cooling of die in the temperature range 600�100 C with compressed air, spray water and water mist streamed under pressure 0.35 0.45 MPa in air jet0.3 0.4 MPa .At the paper are shown results of cooling die�s flat wall using open cooling system. The temperature gradient was presented at die�s wallthickness and calculated thermal curve for cooling surface. The calculation results o...
Directory of Open Access Journals (Sweden)
Full Text Available Die casting moulds and injection moulding are cooled by conventional water jacket method. Cooling of mould is very essential for the purpose of quality of parts and cycle time. The conventional water jackets methods used are having many disadvantages, due to which the effect of mould cooling is not optimum. Hence a technique which can overcome all the disadvantages and become optimum emerged. The main aim of this proposed work is to improve conventional water jackets methods in mould cooling by the application of heat pipe. Heat pipeplays an very important role in such situations, and shows effective results, there by improving the conventional water jacket method in mould cooling. It transfers heat many times faster than pure copper.
Contributions to the design and optimization of dry cooling systems of thermal power plants
International Nuclear Information System (INIS)
A computer program has been established to calculate the thermal performance of a crossflow heat exchanger as a compound of elemental cross flow cells. This program calculates also the outlet temperature distributions, which are of importance for the fluid flow investigations. Based on the existing Forgo concept with six parallel rows of tubes, possible multi-pass structures for the improvement of thermodynamic performances have been investigated. The results show that a three-pass structure is the best choice. Dry cooling towers equipped with standard and modified Forgo-type cooling elements have been designed. The results indicate that the heights of the cooling towers do not differ much. Fewer cooling deltas are, however, needed in a cooling tower using modified elements with increased fin depth. Consequently the base diameter of the cooling tower will be smaller. The cost of the towers with modified heat exchangers will not necessarily be cheap. Electricity generating cost of a 1000 MW nuclear power plant is also slightly higher, if modified elements instead of standard elements are used. An advanced concept of dry cooling of large-scale nuclear power plants with refrigerants has been investigated. For the cooling of LWR (Light Water Reactor) power plants, ammonia is the most suitable candidate. Ammonia gives a smaller cooling tower than when water is used as coolant. Fluorinated hydrocarbons are not suitable for this application. The cooling of HHT (High Temperature Reactor with Helium Turbine) power plants with refrigerants seems to be promising. Further investigations in this field with ammonia and R11 appear worthwhile. (author)
78 FR 64029 - Cost-Benefit Analysis for Radwaste Systems for Light-Water-Cooled Nuclear Power Reactors
...Radwaste Systems for Light-Water-Cooled Nuclear Power Reactors AGENCY: Nuclear Regulatory Commission. ACTION: Regulatory...Radwaste Systems for Light-Water-Cooled Nuclear Power Reactors,'' in which the NRC made editorial...
Evaluation of cooling water consumption and the supply of demands - basic principles
International Nuclear Information System (INIS)
The publication focuses on problems connected with water quantities giving further clues to the appropriate evaluation of cooling water extractions. Apart from data informing about the water demand of different users the publication points out feasible measures providing for a balanced water management. (orig./HP)
Ion Exchange Softening and Alkalization Treatment for Zerodischarge of Circulating Cooling Water
Fei Yu; Xiaolan Chen; Lihui Tong; Chunsong Ye; Huiming Zeng; Jiuyang Lin
In order to solve the problems including pipe corrosion, scaling and microbial growth, which severely threat safe op-eration of circulating cooling water system, this paper proposes ion exchange softening and alkalization process to solve these problems and carries out a series of studies to study the feasibility of ion exchange softening and alkaliza-tion process in the simulation process of circulating cooling water system. The studies include product water quality of ion exchange softening...
Power plant cooling systems: trends and challenges
International Nuclear Information System (INIS)
A novel design for an intake and discharge system at the Belle River plant is described followed by a general discussion of water intake screens and porous dikes for screening fish and zooplankton. The intake system for the San Onofre PWR plant is described and the state regulations controlling the use of water for power plants is discussed. The use of sewage effluent as a source of cooling water is mentioned with reference to the Palo Verde plant. Progress in dry cooling and a new wet/dry tower due to be installed at the San Juan plant towards the end of this year, complete the survey
Acoustic Imaging Evaluation of Juvenile Salmonid Behavior in the Immediate Forebay of the Water Temperature Control Tower at Cougar Dam, 2010
Energy Technology Data Exchange (ETDEWEB)
Khan, Fenton; Johnson, Gary E.; Royer, Ida M.; Phillips, Nathan RJ; Hughes, James S.; Fischer, Eric S.; Ploskey, Gene R.
This report presents the results of an evaluation of juvenile Chinook salmonid (Oncorhynchus tshawytscha) behavior in the immediate forebay of the Water Temperature Control (WTC) tower at Cougar Dam in 2010. The study was conducted by the Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers. The overall goal of the study was to characterize juvenile salmonid behavior and movement patterns in the immediate forebay of the WTC tower for fisheries resource managers to use to make decisions on bioengineering designs for long-term structures and/or operations to facilitate safe downstream passage for juvenile salmonids. We collected acoustic imaging (Dual-Frequency Identification Sonar; DIDSON) data from February 1, 2010 through January 31, 2011 to evaluate juvenile salmonid behavior year-round in the immediate forebay surface layer of the WTC tower (within 20 m, depth 0-5 m). From October 28, 2010 through January 31, 2011 a BlueView acoustic camera was also deployed in an attempt to determine its usefulness for future studies as well as augment the DIDSON data. For the DIDSON data, we processed a total of 35 separate 24-h periods systematically covering every other week in the 12-month study. Two different 24-hour periods were processed for the BlueView data for the feasibility study. Juvenile salmonids were present in the immediate forebay of the WTC tower throughout 2010. The juvenile salmonid abundance index was low in the spring (<200 fish per sample-day), began increasing in late April and peaked in mid-May. Fish abundance index began decreasing in early June and remained low in the summer months. Fish abundance increased again in the fall, starting in October, and peaked on November 8-9. A second peak occurred on December 22. Afterwards, abundance was low for the rest of the study (through January 2011). Average fish length for juvenile salmonids during early spring 2010 was 214 {+-} 86 mm (standard deviation). From May through early November, average fish length remained relatively consistent (132 {+-} 39 mm), after which average lengths increased to 294 {+-} 145 mm for mid-November though early December. Fish behavior analysis indicates milling in front of the intake tower was the most common behavior observed throughout the study period (>50% of total fish events). The next most common movement patterns were fish traversing along the front of the tower, east-to-west and west-to-east. The proportion of fish events seen moving into (forebay to tower) or out of (tower to forebay) the tower was generally low throughout the spring, summer, and early fall for both directions combined. From mid-December 2010 through the end of the study, the combined proportions of fish moving into and out of the tower were higher than previous months of this study. Schooling behavior was most distinct in the spring from late April through mid-June. Schooling events were present in 30 - 96% of the fish events during that period, with a peak in mid-May. Schooling events were also present in the summer, but at lower numbers. Diel distributions for schooling fish during spring, fall, and winter months indicate schooling was concentrated during daylight hours. No schooling was observed at night. Predator activity was observed during late spring, when fish abundance and schooling were highest for the year, and again in the fall months when fish events increased from a summer low. No predator activity was observed in the summer, and little activity occurred during the winter months. For the two days of BlueView data analyzed for vertical distribution in the forebay, a majority of fish (>50%) were present in the middle of the water column (10 - 20 m deep). Between 20 and 41 % of total fish abundance were found in the bottom of the water column (20 - 30 m deep). Few fish were observed in the top 10 m of the water column.
Ion Exchange Softening and Alkalization Treatment for Zerodischarge of Circulating Cooling Water
Directory of Open Access Journals (Sweden)
Fei Yu
Full Text Available In order to solve the problems including pipe corrosion, scaling and microbial growth, which severely threat safe op-eration of circulating cooling water system, this paper proposes ion exchange softening and alkalization process to solve these problems and carries out a series of studies to study the feasibility of ion exchange softening and alkaliza-tion process in the simulation process of circulating cooling water system. The studies include product water quality of ion exchange softening and alkalization process, effect on the performance of carbon steel and brass, and the inhibition that suppresses microbial growth. The results indicate that ion exchange softening and alkalization process is feasible to prevent the circulating cooling water system from scaling, pipe corrosion, and microbial growth without any other chemicals. Thus circulating cooling water system can achieve zerodischarge of wastewater.
Design measures in evolutionary water cooled reactors to optimize for economic viability
International Nuclear Information System (INIS)
Since the mid 1980s, there have been various efforts to develop evolutionary water cooled reactors based on the current operating plant experience. To sustain and improve the economic viability, particular attention has been paid to the following aspects in developing evolutionary water cooled reactors: design simplification and increased operating margins, standardization in design as well as construction and operation, integration of operating plant insights, and consideration of safety, operability and constructability during the design stage. This paper reviews each item and discusses several examples from some of the evolutionary water cooled reactors being developed. (author)
Thermohydraulic relationships for advanced water cooled reactors, and the role of IAEA
International Nuclear Information System (INIS)
Under the auspices of the International Atomic Energy Agency (IAEA) a Coordinated Research Program (CRP) on Thermohydraulic Relationships for Advanced Water-Cooled Reactors was carried out from 1995-1999. It was included into the IAEA's Programme following endorsement in 1995 by the IAEA's International Working Group on Advanced Technologies for Water Cooled Reactors. The overall goal was to promote international information exchange and cooperation in establishing a consistent set of thermohydraulic relationships that are appropriate for use in analyzing the performance and safety of advanced water cooled reactors. (authors)
Development and characterization of aluminum stranded water cooled conductor for rapid cycling synchrotron magnets
International Nuclear Information System (INIS)
Magnet coils of rapid cycling synchrotron are subjected to time varying magnetic fields and a special water cooled stranded conductor is preferred for making magnet coils to reduce eddy current losses, magnetic field inhomogeneity and operating costs of magnets. A continuous length (? 50 m) aluminum stranded water cooled conductor is indigenously developed. Five stranded magnet coils are wound and epoxy resin impregnated as per the technical requirements. The stranded conductor magnet coils are assembled with a laminated dipole magnet core for their electrical characterization. The development of water cooled aluminum stranded conductor, characterization of stranded magnet coils will be discussed in this paper. (author)
Thermohydraulic relationships for advanced water cooled reactors and the role of the IAEA
International Nuclear Information System (INIS)
Under the auspices of the International Atomic Energy Agency (IAEA) a Coordinated Research Program (CRP) on Thermohydraulic Relationships for Advanced Water-Cooled Reactors was carried out from 1995-1998. It was included into the IAEA's Programme following endorsement in 1995 by the International Working Group on Advanced Technologies for Water Cooled Reactors. The overall goal was to promote International Information exchange and cooperation in establishing a consistent set of thermohydraulic relationships that are appropriate for use in analyzing the performance and safety of advanced water-cooled reactors. (authors)
Containment for Heavy-Water Gas-Cooled Reactors
International Nuclear Information System (INIS)
The safety principles applicable to heavy-water, gas-cooled reactors are outlined, with a view to establishing containment specifications adapted to the sites available in Switzerland for the construction of nuclear plants. These specifications are derived from dose rates considered acceptable, in the event of a serious reactor accident, for persons living near the plant, and are based on-meteorological and demographic conditions representative of the majority of the country's sites. The authors consider various designs for the containment shell, taking into account the conditions which would exist in the shell after the maximum credible accident. The following types of shell are studied: pre-stressed concrete; pre-stressed concrete with steel dome; pre-stressed concrete with inner, leakproof steel lining; steel with concrete side shield to protect against radiation; double shell. The degree of leak proofing of the shells studied is regarded as a feature of the particular design and not as a fixed constructional specification. The authors assess the leak proofing properties of each type of shell and establish building costs for each of them on the basis of precise plans, with the collaboration of various specialized firms. They estimate the effectiveness of the various shells from a safety standpoint, in relation to different emergency procedures, in particular release into the atmosphere through appropriate filters and decontamination of the air within the shell by ramination of the air within the shell by recycling through batteries of filters. The paper contains a very detailed comparison of about 10 cases corresponding to various combinations of design and emergency procedure; the comparison was made using a computer programme specially established for the purpose. The results are compared with those for a reactor of the same type and power, but assembled together with the heat exchangers in a pre-stressed concrete shell. (author)
Review of heat transfer behavior in supercritical water cooled reactor
International Nuclear Information System (INIS)
Supercritical water cooled reactor (SCWR) is one of the six reactor technologies under the US led generation IV international forum (GIF). SCWRs are promising advanced nuclear systems because of their high thermal efficiency (i.e., about 45% as opposed to about 33% for current LWRs) and considerable plants implification with a mission to generate low cost electricity. Various types of SCWRs i.e., pressure vessel type,pressure tube type etc. are under development stage. Literature survey showed that the majority of experimental data for measuring fluid temperature and wall temperature by varying pressure, mass flux, heat flux and geometry were obtained in vertical tubes, some data in horizontal tubes and annuli, and a few in other flow geometries including scaled down fuel bundles. But, actually fuel bundles are used in SCWR core. Therefore, more experimental data are needed for fuel bundles to verify the prediction of heat transfer coefficient. Empirical generalised correlations based on experimental data are obtained for heat transfer coefficient calculations at supercritical pressures. However, there is no consensus on the general trends in the predictions of heat transfer coefficient CFD codes are also used for the prediction of heat transfer coefficients. Wide variation in the prediction of the results is also observed for various turbulence models like standard k?,k?, RNG, RSM etc. In this paper heat transfer co-efficient obtained by experimental results, empir obtained by experimental results, empirical correlations and with the use of CFD code is discussed. In general, the experiments showed that there are three heat transfer modes of fluid at supercritical pressure: normal heat transfer, improved heat transfer and deteriorated heat transfer.Heat transfer at critical and pseudocritical pressures is influenced by the significant changes in thermo-physical properties. Mechanism for enhancement/deterioration in heat transfer and criteria for onset of deterioration has also been discussed in this paper. Two important issues are identified which needs to be resolved for thermal-hydraulics/regulatory point of view: (a) heat transfer deterioration near pseudocritical temperature which leads to increase in wall temperature similar to dryout in LWRs, (b) fuel design criteria based on the critical heat flux is not applicable for the SCWRs because of no phase change of water inside the core. (author)
The impact of water use fees on dispatching and water requirements for water-cooled power plants in Texas.
Sanders, Kelly T; Blackhurst, Michael F; King, Carey W; Webber, Michael E
We utilize a unit commitment and dispatch model to estimate how water use fees on power generators would affect dispatching and water requirements by the power sector in the Electric Reliability Council of Texas' (ERCOT) electric grid. Fees ranging from 10 to 1000 USD per acre-foot were separately applied to water withdrawals and consumption. Fees were chosen to be comparable in cost to a range of water supply projects proposed in the Texas Water Development Board's State Water Plan to meet demand through 2050. We found that these fees can reduce water withdrawals and consumption for cooling thermoelectric power plants in ERCOT by as much as 75% and 23%, respectively. To achieve these water savings, wholesale electricity generation costs might increase as much as 120% based on 2011 fuel costs and generation characteristics. We estimate that water saved through these fees is not as cost-effective as conventional long-term water supply projects. However, the electric grid offers short-term flexibility that conventional water supply projects do not. Furthermore, this manuscript discusses conditions under which the grid could be effective at "supplying" water, particularly during emergency drought conditions, by changing its operational conditions. PMID:24832169
Comparison of solar panel cooling system by using dc brushless fan and dc water
Irwan, Y. M.; Leow, W. Z.; Irwanto, M.; M, Fareq; Hassan, S. I. S.; Safwati, I.; Amelia, A. R.
The purpose of this article is to discuss comparison of solar panel cooling system by using DC brushless fan and DC water pump. Solar photovoltaic (PV) power generation is an interesting technique to reduce non-renewable energy consumption and as a renewable energy. The temperature of PV modules increases when it absorbs solar radiation, causing a decrease in efficiency. A solar cooling system is design, construct and experimentally researched within this work. To make an effort to cool the PV module, Direct Current (DC) brushless fan and DC water pump with inlet/outlet manifold are designed for constant air movement and water flow circulation at the back side and front side of PV module representatively. Temperature sensors were installed on the PV module to detect temperature of PV. PIC microcontroller was used to control the DC brushless fan and water pump for switch ON or OFF depend on the temperature of PV module automatically. The performance with and without cooling system are shown in this experiment. The PV module with DC water pump cooling system increase 3.52%, 36.27%, 38.98%in term of output voltage, output current, output power respectively. It decrease 6.36 �C compare than to PV module without DC water pump cooling system. While DC brushless fan cooling system increase 3.47%, 29.55%, 32.23%in term of output voltage, output current, and output power respectively. It decrease 6.1 �C compare than to PV module without DC brushless fan cooling system. The efficiency of PV module with cooling system was increasing compared to PV module without cooling system; this is because the ambient temperature dropped significantly. The higher efficiency of PV cell, the payback period of the system can be shorted and the lifespan of PV module can also be longer.
Water mist effect on cooling range and efficiency of casting die
Directory of Open Access Journals (Sweden)
R. W?adysiak
Full Text Available This project is showing investigation results of cooling process of casting die in the temperature range 570�100 �C with 0.40 MPa compressed air and water mist streamed under pressure 0.25�0.45 MPa in air jet 0.25�0.50 MPa using open cooling system.The character and the speed of changes of temperature, forming of the temperture�s gradient along parallel layer to cooled surface of die is shawing with thermal and derivative curves. The effect of kind of cooling factor on the temperature and time and distance from cooling nozzle is presented in the paper. A designed device for generating the water mist cooling the die and the view of sprying water stream is shown here. It�s proved that using of the water mist together with the change of heat transfer interface increases intensity of cooling in the zone and makes less the range cooling zone and reduces the porosity of cast microstructure.
Thermal design of lithium bromide-water solution vapor absorption cooling system for indirect evaporative cooling for IT pod
Sawant, Digvijay Ramkrishna
Nowadays with increase use of internet, mobile there is increase in heat which ultimately increases the efficient cooling system of server room or IT POD. Use of traditional ways of cooling system has ultimately increased CO2 emission and depletion of CFC's are serious environmental issues which led scientific people to improve cooling techniques and eliminate use of CFC's. To reduce dependency on fossil fuels and 4environmental friendly system needed to be design. For being utilizing low grade energy source such as solar collector and reducing dependency on fossil fuel vapour absorption cooling system has shown a great driving force in today's refrigeration systems. This LiBr-water aabsorption cooling consists of five heat exchanger namely: Evaporator, Absorber, Solution Heat Exchanger, Generator, Condenser. The thermal design was done for a load of 23 kW and the procedure was described in the thesis. There are 120 servers in the IT POD emitting 196 W of heat each on full load and some of the heat was generated by the computer placed inside the IT POD. A detailed procedure has been discussed. A excel spreadsheet was to prepared with varying tube sizes to see the effect on flows and ultimately overall heat transfer coefficient.
Comparisons of the Raman lidar measurements of the tropospheric water vapor profiles with radiosondes, meteorological observation tower, and GPS at Tsukuba, Japan
Sakai, Tetsu; Nagai, Tomohiro; Nakazato, Masahisa; Matsumura, Takatsugu; Orikasa, Narihiro; Shoji, Yoshinori
The vertical distributions of the water vapor mixing ratio (w) were measured by Raman lidar at the Meteorological Research Institute, Japan, in 2000 to 2004. The measured values were compared with those obtained with radiosondes, hygrometers on the meteorological observation tower, and Global Positional System (GPS) antennas. The values of w obtained with the lidar agreed within 9% with those obtained with the Meisei RS2-91 radiosonde for w > 0.5 g/kg -1. However, they were systematically higher than those obtained with the Vaisala RS80-A radiosonde for that region. The vertical variations of w obtained with the lidar were similar to those obtained with the Meisei RS-01G and Meteolabor Snow White radiosondes for w > 0.3 g/kg -1. The temporal variations of w obtained with the lidar were similar to those obtained with the hygrometers at heights between 50 and 213 m on the tower, although the absolute values differed systematically due to the incomplete overlap of the laser beam and the receiver's field of view at the lower heights. The precipitable water vapor content obtained with the lidar generally agreed with those obtained with GPS, except for the period when the large spatial inhomogeneity of w was present.
Structure of Water Mist Stream and its Impact on Cooling Efficiency of Casting Die
R.W?adysiak; P. Budzy?ski
The work is a continuation of research on the use water mist cooling in order to increase efficiency of die-casting aluminum alloys. The paper presents results of research and analysis process, spraying water and generated a stream of water mist, the effect of the type of nozzle, the nozzle size and shape of the emitting of the water mist on the wall surface of casting die on the microstructure and geometry of water mist stream and cooling efficiency. Tests were used to perform high-speed cam...
Instrumentation for monitoring and control of water chemistry for light-water-cooled nuclear power plants
International Nuclear Information System (INIS)
Based on the IAPWS technical guidance on ''Instrumentation for Monitoring and Control of Cycle Chemistry for Steam-Water Circuits of Fossil-Fired and Combined Cycle Power Plants,'' the latest situation regarding instrumentation for nuclear power plants is discussed. As a result of the discussion, it is concluded that: (1) Reliable and safe operation of plants is established by the application of suitable chemical conditions in plant cooling systems, which should be supported by the selection of suitable control targets for monitoring and by the application of reliable instruments. (2) The minimum level of key instrumentation consists of on-line as well as off-line instruments for monitoring the key parameters: - on-line: pH, conductivity, cation conductivity, O2 and H2 concentrations, electrochemical corrosion potential; - off-line: radioactive nuclides (60Co, 58Co, 131I, etc.), and the concentrations of metallic species (Fe, Cu, Co, etc.) and other species (B, Li, N2H4). (3) The application of high-temperature water chemistry sensors for in-situ measurement of cooling water properties and diagnosis of anomalous conditions based on monitored data is an important consideration for the future. (4) A technical guidance for nuclear plants, similar to the one issued for instrumentation and monitoring of chemistry in fossil-fired and combined-cycle plants, may be useful in the future, when common fmay be useful in the future, when common features could be combined in a unified guidance. (orig.)
The Maximum Drop-Height of a Droplet in a Vertical Countercurrent Water-Air Heat and Moisture Exchange Tower Attached to a Main Fan Diffuser in a Coal Mine
Chen, S.; Cui, H.; Wang, H.; Zhao, J.
A vertical countercurrent water-air heat and moisture exchange tower attached to a main fan diffuser is designed. To reduce water loss blown away by the airflow from the exchange tower, the forces acting on droplets are analysed. Droplet motion may be classified under four conditions: (1) downward initial acceleration; (2) upward initial acceleration; (3) droplet blown away by airflow; (4) droplet suspension. With droplet break-up neglected, a general equation for the maximum droplet drop-height is presented and numerical calculations are performed. Equations for the maximum drop-height under Conditions 3 and 4 are deduced, and the equation for Condition 3 is applied to an engineering case study. The effect of air velocity on the maximum drop-height is more significant than that of other factors. The conclusions provide a novel approach to optimizing the design of vertical countercurrent water-air heat and moisture exchange towers attached to main fan diffusers.
Cooling device for spontaneous heat dissipation type container
International Nuclear Information System (INIS)
A device of the present invention conducts cooling stably for a long period of time while requiring neither particular power nor operator's handling. That is, a reactor container cooling device having a plurality of heat conduction pipes is disposed on the inner side of a reactor container. A steam injector and an air-cooling tower are connected to the cooling device, and a cooling water pool is disposed between the injector and the air-cooling tower. In the device thus constituted, since the heat in the reactor container can be released to the atmosphere through the heat conductive surface of the reactor container cooling device, cooling after LOCA can be conducted stably without using for a long period of time. Further, since the heat of the reactor container can be removed for a long period of time with a small amount of cooling water, the size of reactor buildings incorporating the cooling water pool can be minimized. The spontaneous heat dissipation type reactor container described above has a great industrial advantage in view of structural integrity of the reactor buildings and saving of construction cost. (I.S.)
Wetland Water Cooling Partnership: The Use of Constructed Wetlands to Enhance Thermoelectric Power Plant Cooling and Mitigate the Demand of Surface Water Use
Energy Technology Data Exchange (ETDEWEB)
Apfelbaum, Steven; Duvall, Kenneth; Nelson, Theresa; Mensing, Douglas; Bengtson, Harlan; Eppich, John; Penhallegon, Clayton; Thompson, Ry
Through the Phase I study segment of contract #DE-NT0006644 with the U.S. Department of Energy�s National Energy Technology Laboratory, Applied Ecological Services, Inc. and Sterling Energy Services, LLC (the AES/SES Team) explored the use of constructed wetlands to help address stresses on surface water and groundwater resources from thermoelectric power plant cooling and makeup water requirements. The project objectives were crafted to explore and develop implementable water conservation and cooling strategies using constructed wetlands (not existing, naturally occurring wetlands), with the goal of determining if this strategy has the potential to reduce surface water and groundwater withdrawals of thermoelectric power plants throughout the country. Our team�s exploratory work has documented what appears to be a significant and practical potential for augmenting power plant cooling water resources for makeup supply at many, but not all, thermoelectric power plant sites. The intent is to help alleviate stress on existing surface water and groundwater resources through harvesting, storing, polishing and beneficially re-using critical water resources. Through literature review, development of conceptual created wetland plans, and STELLA-based modeling, the AES/SES team has developed heat and water balances for conventional thermoelectric power plants to evaluate wetland size requirements, water use, and comparative cooling technology costs. The ecological literature on organism tolerances to heated waters was used to understand the range of ecological outcomes achievable in created wetlands. This study suggests that wetlands and water harvesting can provide a practical and cost-effective strategy to augment cooling waters for thermoelectric power plants in many geographic settings of the United States, particularly east of the 100th meridian, and in coastal and riverine locations. The study concluded that constructed wetlands can have significant positive ancillary socio-economic, ecosystem, and water treatment/polishing benefits when used to complement water resources at thermoelectric power plants. Through the Phase II pilot study segment of the contract, the project team partnered with Progress Energy Florida (now Duke Energy Florida) to quantify the wetland water cooling benefits at their Hines Energy Complex in Bartow, Florida. The project was designed to test the wetland�s ability to cool and cleanse power plant cooling pond water while providing wildlife habitat and water harvesting benefits. Data collected during the monitoring period was used to calibrate a STELLA model developed for the site. It was also used to inform management recommendations for the demonstration site, and to provide guidance on the use of cooling wetlands for other power plants around the country. As a part of the pilot study, Duke Energy is scaling up the demonstration project to a larger, commercial scale wetland instrumented with monitoring equipment. Construction is expected to be finalized in early 2014.
Fluid Induced Vibration Analysis of a Cooling Water Pipeline for the HANARO CNS
International Nuclear Information System (INIS)
CNS is the initial of Cold Neutron Source and the CNS facility system consists of hydrogen, a vacuum, a gas blanketing, a helium refrigeration and a cooling water supply system. Out of these subsystems, the helium refrigeration system has the function of removal of heat from a thermal neutron under reactor operation. Therefore, HRS (helium refrigeration system) must be under normal operation for the production of cold neutron. HRS is mainly made up of a helium compressor and a coldbox. This equipment is in need of cooling water to get rid of heat generation under stable operation and a cooling water system is essential to maintain the normal operation of a helium compressor and a coldbox. The main problem for the cooling water system is the vibration issue in the middle of operation due to a water flow in a pipeline. In order to suppress the vibration problem for a pipeline, the characteristics of a pipeline and fluid flow must be analyzed in detail. In this paper, fluid induced vibration of a cooling water pipe is analyzed numerically and the stability of the cooling water pipeline is investigated by using pipe dynamic theory
Seismic qualification of re-circulatory type cooling water system at RLG
International Nuclear Information System (INIS)
At Radiological Labs. (RLG), BARC, Trombay, there are number of electrically operated high temperature high thermal capacity equipment which are usually operated in confined environment like Glove Boxes (GBs). They require continuous cooling water of significant quantities during operation as well as for safe shutdown condition. Presently these equipment's are cooled with normal water on once-through basis. This mode of cooling not only consumes huge quantities of normal water but also generates same quantity of liquid effluent to be treated. Though an emergency cooling water system is available at present to cater emergency situations like failure of normal water supply, the system has active components like pumps and needs manual intervention. To overcome these shortfalls, it is proposed to set up a gravity fed (passive) re-circulatory type cooling water system. This paper deals with the seismic qualification of the proposed re-circulatory type cooling water system at RLG. It also discusses in details that how final supporting arrangements have been arrived at to take care of various loadings on the system. (author)
Study of water radiolysis in relation with the primary cooling circuit of pressurized water reactors
International Nuclear Information System (INIS)
This memorandum shows a fundamental study on the water radiolysis in relation with the cooling primary circuit of PWR type reactors. The water of the primary circuit contains boric acid a soluble neutronic poison and also hydrogen that has for role to inhibit the water decomposition under radiation effect. In the aim to better understand the mechanism of dissolved hydrogen action and to evaluate the impact of several parameters on this mechanism, aqueous solutions with boric acid and hydrogen have been irradiated in a experimental nuclear reactor, at 30, 100 and 200 Celsius degrees. It has been found that, with hydrogen, the water decomposition under irradiation is a threshold phenomenon in function of the ratio between the radiation flux '1' B(n, )'7 Li and the gamma flux. When this ratio become too high, the number of radicals is not sufficient to participate at the chain reaction, and then water is decomposed in O2 and H2O2 in a irreversible way. The temperature has a beneficial part on this mechanism. The iron ion and the copper ion favour the water decomposition. (N.C.)
Effects of Water Radiolysis in Water Cooled Reactors, NERI Proposal No.99-0010
International Nuclear Information System (INIS)
OAK B188 Effects of Water Radiolysis in Water Cooled Reactors, NERI Proposal No.99-0010. The aim of this project is to develop an experiment-and-theory based model for the radiolysis of nonstandard aqueous systems like those that will be encountered in the Advance Light Water reactor. Three aspects of the radiation chemistry of aqueous systems at elevated temperatures are considered in the project: the radiation-induced reaction within the primary track and with additives, the homogeneous production of H2O2 at high radiation doses, and the heterogeneous reaction of the radiation-induced species escaping the track. The goals outlined for Phase 1 of the program were: the compilation of information on the radiation chemistry of water at elevated temperatures, the simulation of existing experimental data on the escape yields of eaq-, OH, H2 and H2O2 in ? radiolysis at elevated temperatures, the measurement of low LET and high LET production of H2O2 at room temperature, the compilation of information on the radiation chemistry of water-(metal) oxide interfaces, and the synthesis and characterization the heterogeneous water-oxide systems of interest
Performance test of filtering system for controlling the turbidity of secondary cooling water in HANARO
International Nuclear Information System (INIS)
There is about 80 m3/h loss of the secondary cooling water by evaporation, windage and blowdown during the operation of HANARO, 30 MW research reactor. When the secondary cooling water is treated by high Ca-hardness treatment program for minimizing the blowdown loss, only the trubidity exceeds the limit. By adding filtering system it was confirned, through the relation of turbidity and filtering rate of secondary cooling water, that the turbidity is reduced below the limit (5 deg.) by 2 % of filtering rate without blowdown. And it was verified, through the field performace test of filtering system under normal operation condition, that the circulation pumps get proper capacity and that filter units reduce the turbidity below the limit. Therefore, the secondary cooling water can be treated by the high Ca-hardness program and filter system without blowdown
Development of Non-water cooling Induction coil of Ingot Casting Equipment for Uranium Deposits
International Nuclear Information System (INIS)
The ingot casting equipment for uranium deposits is to make an ingot with uranium deposits produced from an electro-refiner by a pyro-processing method. The ingot casting equipment consists of crucible, feeder and mold. The crucible is heated by induction coil. Usually in industry they use a water-cooling induction coil for there is a lot of heat generation through the heating coil. We introduce a new idea to improve safety with non-water cooling coil in ingot casting equipment for uranium deposits, because in the hot-cell operation, if there were leakage from water-cooling induction coil, there could be a troublesome accident. In this paper, we introduce the experimental results of non-water cooling induction coil
Water mist effect on cooling range and efficiency of casting die
This project is showing investigation results of cooling process of casting die in the temperature range 570�100 �C with 0.40 MPa compressed air and water mist streamed under pressure 0.25�0.45 MPa in air jet 0.25�0.50 MPa using open cooling system.The character and the speed of changes of temperature, forming of the temperture�s gradient along parallel layer to cooled surface of die is shawing with thermal and derivative curves. The effect of kind of cooling factor on the temperature and tim...
Achieving reduced fouling of cooling water exchangers with stainless steel tubes
International Nuclear Information System (INIS)
Good performance of cooling water heat exchangers plays a vital role in the over all energy efficiency of a chemical plant. Heavy fouling on carbon steel tubes of the cooling water exchangers was causing poor performance and frequent cleaning requirement. The carbon steel tubes were replaced with stainless steel tubes. Improved performance was achieved and cleaning frequency reduced. The paper covers the details of study and methodology applied for the above changes along with summary of results. (author)
Concentration of radio active elements in primary cooling water at reactor operation of JMTR
International Nuclear Information System (INIS)
Concentrations of radioactive elements in primary cooling water were measured by regular sampling on reactor operation of the JMTR. The JMTR core was converted to Low enriched uranium core at the 108th operation cycle, and the refurbishment of the JMTR has been started after the 165th operation cycle. Measured results of concentrations of gamma-ray release elements, radioactive iodine and tritium in primary cooling water were summarized during 108-165th operation cycles. (author)
Heat transfer analysis during cooling of die with use of water mist
Directory of Open Access Journals (Sweden)
R. W?adysiak
Full Text Available The paper presents the results of the heat transfer area during the cooling process of steel test die with water mist which consist the flow of air in the range 150�350 l/min and 0.05 0.24 l/min of water. Temperature change in the thickness of die by means showing with the thermal curves and the temperature gradient and temperature distribution in the space between the nozzle and the cooled surface of the metal mold using a thermal imaging camera and thermocouples measurement. The course of changes in the temperature gradient and the received heat flux from the die while cooling its with the flow of air and water mist stream. It has been shown that the use of water mist with a variable flow of air and water controls the process of heat transfer process between the permanent molds, and a stream of water mist.
Kinetic model for predicting the concentrations of active halogen species in chlorinated saline cooling waters
International Nuclear Information System (INIS)
A kinetic model for predicting the composition of chlorinated water discharged from power plants using fresh water for cooling was previously reported. The model has now been extended to be applicable to power plants located on estuaries or on the seacoast where saline water is used for cooling purposes. When chloride is added to seawater to prevent biofouling in cooling systems, bromine is liberated. Since this reaction proceeds at a finite rate there is a competition between the bromine (i.e., hypobromous acid) and the added chlorine (i.e., hypochlorous acid) for halogenation of any amine species present in the water. Hence not only chloramines but also bromamines and bromochloramines will be formed, with the relative concentrations a function of the pH, temperature, and salinity of the water. The kinetic model takes into account the chemical reactions leading to the formation and disappearance of the more important halamines and hypohalous acids likely to be encountered in chlorinated saline water
Closed-cycle process of coke-cooling water in delayed coking unit
International Nuclear Information System (INIS)
Synthesized processes are commonly used to treat coke-cooling wastewater. These include cold coke-cut water, diluting coke-cooling water, adding chemical deodorization into oily water, high-speed centrifugal separation, de-oiling and deodorization by coke adsorption, and open nature cooling. However, because of water and volatile evaporation loss, it is not suitable to process high-sulphur heavy oil using open treatments. This paper proposed a closed-cycling process in order to solve the wastewater treatment problem. The process is based on the characteristics of coke-cooling water, such as rapid parametric variation, oil-water-coke emulsification and steam-water mixing. The paper discussed the material characteristics and general idea of the study. The process of closed-cycle separation and utilization process of coke-cooling water was presented along with a process flow diagram. Several applications were presented, including a picture of hydrocyclones for pollution separation and a picture of equipments of pollution separation and components regeneration. The results showed good effect had been achieved since the coke-cooling water system was put into production in 2004. The recycling ratios for the components of the coke-cooling water were 100 per cent, and air quality in the operating area reached the requirements of the national operating site circumstance and the health standards. Calibration results of the demonstration unit were presented. It was concluded tha unit were presented. It was concluded that since the devices went into operation, the function of production has been normal and stable. The operation was simple, flexible, adjustable and reliable, with significant economic efficiency and environmental benefits. 10 refs., 2 tabs., 3 figs
Possible efficiency improvement by application of various operating regimes for the cooling water pump station at thermal power plant - Bitola
Mijakovski Vladimir; Mitrevski Vangel?e; Mijakovski Nikola
Thermal power plant (TPP) - Bitola is the largest electricity producer in the Republic of Macedonia with installed capacity of 691 MW. It is a lignite fired power plant, in operation since 1982. Most of the installed equipment is of Russian origin. Power plant's cold end comprised of a condenser, pump station and cooling tower is depicted in the article. Possible way to raise the efficiency of the cold end by changing the operating characteristics of the pumps is presented in the articl...
The comparison of designed water-cooled and air-cooled passive residual heat removal system for 300 MW nuclear power plant during the feed-water line break scenario
International Nuclear Information System (INIS)
Highlights: ? The PRHRSs are designed for 300 MW PWR. ? Two cooling patterns (water-cooled and air-cooled) are adopted in the PRHRSs. ? The characteristics comparison of two type PRHRSs are performed during FLB accident. ? The characteristics comparison of two type PRHRSs are performed during FLB accident. ? The ACPRHRS is more effective for long term cooling. - Abstract: The steam generator (SG) secondary water-cooled and air-cooled passive residual heat removal systems (PRHRSs) are proposed and designed for 300 MW Pressurized Water Reactor (PWR). The RELAP5/MOD3.4 code is utilized to study the behavior of the PRHRSs and transient characteristics of primary loop system during Feed-water Line Break (FLB) accident. The characteristic comparison between water-cooled and air-cooled PRHRSs is also conducted in this study. The results show that both water-cooled and air-cooled PRHRSs can establish stable natural circulations in PRHRS loops, which realize the effective core decay heat removal from primary loop. Results illustrate that both water-cooled PRHRS and air-cooled PRHRS designed in the study have great significance for improving the inherent safety of 300 MW nuclear power plant. However, the water-cooled PRHRS heat transfer ability is stronger in the initial time, while it becomes weaker as the system tank water evaporates in the later stage. In contrast, the air-cooled PRHRS, ensuring the main reactor operation parameters to decrease to a more safety value, is more effective than water-cooled PRHRS for long term cooling
Environmental effects of large discharges of cooling water. Experiences from Swedish nuclear power plants
International Nuclear Information System (INIS)
Monitoring the environmental effects of cooling water intake and discharge from Swedish nuclear power stations started at the beginning of the 1960s and continues to this day. In parallel with long-term monitoring, research has provided new knowledge and methods to optimise possible discharge locations and design, and given the ability to forecast their environmental effects. Investigations into the environmental effects of cooling-water are a prerequisite for the issuing of power station operating permits by the environmental authorities. Research projects have been carried out by scientists at universities, while the Swedish Environmental Protection Agency, the Swedish Board of Fisheries, and the Swedish Meteorological and Hydrological Institute, SMHI, are responsible for the greater part of the investigations as well as of the research work. The four nuclear power plants dealt with in this report are Oskarshamn, Ringhals, Barsebaeck and Forsmark. They were taken into operation in 1972, 1975, 1975 and 1980 resp. - a total of 12 reactors. After the closure of the Barsebaeck plants in 2005, ten reactors remain in service. The maximum cooling water discharge from the respective stations was 115, 165, 50 and 135 m3/s, which is comparable to the mean flow of an average Swedish river - c:a 150 m3/s. The report summarizes studies into the consequences of cooling water intake and discharge. Radiological investigations made at the plants are not coveredgations made at the plants are not covered by this review. The strategy for the investigations was elaborated already at the beginning of the 1960s. The investigations were divided into pre-studies, baseline investigations and monitoring of effects. Pre-studies were partly to gather information for the technical planning and design of cooling water intake and outlet constructions, and partly to survey the hydrographic and ecological situation in the area. Baseline investigations were to carefully map the hydrography and ecology in the area and their natural variations caused by changing weather and climate. When cooling water discharges began, the monitoring of effects started, mapping environmental impacts. To ensure that observed environmental changes were caused by cooling water discharges and not by natural variations, parallel measurements were carried out in undisturbed reference areas. The focus of the biological investigations has been directed towards fish using test fishing and daily records of commercial fishing. Age distributions, reproduction, growth, and the prevalence of disease and parasites have been analysed. Fish movements and behaviour related to cooling-water were mapped using mark-recapture experiments. The monitoring of effects included mapping the shape and size of the cooling-water plume and the temperature distribution in the discharge area. For certain biological variables, such as the movement of fish in relation to the cooling water plume, great efforts were made during the first years of power plant operation. In conjunction with the start of the plants, studies were also initiated to estimate the loss of fish on the cooling-water intake screens. Meteorological research projects investigated among other things, the risks for increased fog formation due to the discharge of warm water, while hydrography projects mainly concerned the development of methods for calculating the size and form of the cooling water plumes. Ecological studies were directed to the effects of increasing temperature on the production and degradation of biological material, on the benthic fauna responses, on the risk of fish parasite and disease outbreaks as well as on the combined effects of toxic substances and heat. The possibility of using cooling-water to improve fish recruitment was also studied. In conjunction with the construction of the Forsmark nuclear power plant, an artificial enclosure was made using rock excavated from the cooling water tunnels. Cooling water is led through this basin before discharge into the open 'Oeregrundsgrepen'. This 'Biotest basin' is an impo
Neutron spectrum analysis in a heavy-water-moderated, light-water-cooled reactor
International Nuclear Information System (INIS)
With LAMP-A, a program set for integral transport calculation of thermal reactor lattice cells, the neutron spectra in the core of a D2O-moderated, H2O-cooled, pressure-tube-type, advanced thermal reactor were calculated. The ratio of thermal neutron flux to total neutron flux is large, nearly 50%, and the ratio of fission spectrum neutron flux to total neutron flux is small, about 10%, because the deuterium has large slowing-down power in a heavy water reactor. The conversion rate is about 0.5 in the initial core and about 0.7 in the equilibrium core. These values are smaller than the conversion rate 0.9 of a CANDU-type reactor and also inferior to those of a light-water reactor. By reducing the 235U enrichment, in on-power refueling, therefore, the conversion rate must be increased. (auth.)
Microbial speciation and biofouling potential of cooling water used by Ontario Hydro
International Nuclear Information System (INIS)
The cooling water composition and microbial components of biofilms attached to stainless steel wafers submerged in three lake water types were evaluated to determine whether their biofouling potential differed in a predictable manner. The composition of the lake waters was different which affected biofilm composition, where the predominance of specific microbial groups varied between test systems and with time. Some prediction of biofouling potential was possible, and it was concluded that the cooling water in the vicinity of Bruce NGS had the lowest biofouling potential whereas greater biofouling could be expected in the Pickering and Nanticoke stations
Fluidized bed heat exchanger with water cooled air distributor and dust hopper
Jukkola, Walfred W. (Westport, CT); Leon, Albert M. (Mamaroneck, NY); Van Dyk, Jr., Garritt C. (Bethel, CT); McCoy, Daniel E. (Williamsport, PA); Fisher, Barry L. (Montgomery, PA); Saiers, Timothy L. (Williamsport, PA); Karstetter, Marlin E. (Loganton, PA)
A fluidized bed heat exchanger is provided in which air is passed through a bed of particulate material containing fuel. A steam-water natural circulation system is provided for heat exchange and the housing of the heat exchanger has a water-wall type construction. Vertical in-bed heat exchange tubes are provided and the air distributor is water-cooled. A water-cooled dust hopper is provided in the housing to collect particulates from the combustion gases and separate the combustion zone from a volume within said housing in which convection heat exchange tubes are provided to extract heat from the exiting combustion gases.
Modelization of cooling system components
International Nuclear Information System (INIS)
In the site evaluation study for licensing a new nuclear power facility, the criteria involved could be grouped in health and safety, environment, socio-economics, engineering and cost-related. These encompass different aspects such as geology, seismology, cooling system requirements, weather conditions, flooding, population, and so on. The selection of the cooling system is function of different parameters as the gross electrical output, energy consumption, available area for cooling system components, environmental conditions, water consumption, and others. Moreover, in recent years, extreme environmental conditions have been experienced and stringent water availability limits have affected water use permits. Therefore, modifications or alternatives of current cooling system designs and operation are required as well as analyses of the different possibilities of cooling systems to optimize energy production taking into account water consumption among other important variables. There are two basic cooling system configurations: - Once-through or Open-cycle; - Recirculating or Closed-cycle. In a once-through cooling system (or open-cycle), water from an external water sources passes through the steam cycle condenser and is then returned to the source at a higher temperature with some level of contaminants. To minimize the thermal impact to the water source, a cooling tower may be added in a once-through system to allow air cooling of the water (with associated losses ling of the water (with associated losses on site due to evaporation) prior to returning the water to its source. This system has a high thermal efficiency, and its operating and capital costs are very low. So, from an economical point of view, the open-cycle is preferred to closed-cycle system, especially if there are no water limitations or environmental restrictions. In a recirculating system (or closed-cycle), cooling water exits the condenser, goes through a fixed heat sink, and is then returned to the condenser. This configuration results in relatively low water withdrawal. Typical heat sink options for closed-cycle systems are wet cooling system (mechanical or natural draft cooling towers, and cooling ponds). When water availability is low, a dry cooling system may be utilized. Dry cooling can be either direct or indirect and in each case uses convective heat transfer to provide cooling, eliminating evaporation losses. An innovative indirect dry cooling system is the HellerR System. The HellerR System air moving equipment can be either a natural draft or a mechanical draft. The HellerR System design concepts and equipment provides the maximum possible availability and minimum maintenance. Also, it is totally environmental-friend as saves water equivalent to the consumption of a town of 50,000 inhabitants for each 100 MWe facilitating the licensing of power projects. (authors)
Methods for combating microorganisms in cooling water systems - a literature study and a market inventory
International Nuclear Information System (INIS)
One of the greatest current problems in both closed and open cooling water systems is that of micro- and macro-organisms. In view of the environmental effects associated with the discharge of chemicals, the range of biocides and alternative methods for combating micro-organisms has increased during recent years. This report presents a brief description of the organisms which contribute to corrosion problems and the mechanisms associated with microbial corrosion. Thereafter descriptions are given of 15 different biocides which are used in both open and closed cooling systems. In each case, details are given of their chemical compositions and mode of action and of their effects on metals and on the environment. Finally, alternative methods of combating micro-organisms in cooling water systems are briefly described. The report also includes a survey of the biocides for cooling water systems which are available on the Swedish market. (author)
Operational Experience of Cooling Water Systems for Accelerator Components at PLS
Kim, Kyungryul; Kim, Young-Chan; Lee, Bongho; Sik Han, Hong; Soo Ko In; Wha Chung, Chin
The cooling water system has been utilized for absorbing heat generated by a multitude of electromagnetic power delivering networks at PLS. The separate cooling water distribution systems for the storage ring, beam transport line and linear accelerator have been operated with a different operating temperature of supplying water. All water used for heat removal from the accelerator components are deionised and filtered to provide with over 2 MO-cm specific resistance. The operating pressures and flows of input water are also controlled with flow balancing scheme at a specified range. The operating temperature of components in the accelerator is sustained as tight as below �0.1 deg C to minimize the influence of temperature fluctuation on the beam energy and stability. Although the PLS cooling systems were initially installed with a high degree of flexibility to allow for easy maintenance, a number of system improvements have been employed to enhance operational reliability and to incorporate the newly...
Preparation of semi-solid aluminum alloy slurry poured through a water-cooled serpentine channel
Chen, Zheng-Zhou; Mao, Wei-Min; Wu, Zong-Chuang
A water-cooled serpentine channel pouring process was invented to produce semi-solid A356 aluminum alloy slurry for rheocasting, and the effects of pouring temperature and circulating cooling water flux on the microstructure of the slurry were investigated. The results show that at the pouring temperature of 640-680�C and the circulating cooling water flux of 0.9 m3/h, the semi-solid A356 aluminum alloy slurry with spherical primary ?(Al) grains can be obtained, whose shape factors are between 0.78 and 0.86 and the grain diameter can reach 48-68 ?m. When the pouring temperatures are at 660-680�C, only a very thin solidified shell remains inside the serpentine channel and can be removed easily. When the serpentine channel is cooled with circulating water, the microstructure of the semi-solid slurry can be improved, and the serpentine channel is quickly cooled to room temperature after the completion of one pouring. In terms of the productivity of the special equipment, the water-cooled serpentine channel is economical and efficient.
LiOH as corrosion inhibitor for component cooling water system in PWR
International Nuclear Information System (INIS)
The cooling water system for the auxiliary machines and coolers in the primary cooling system of a PWR forms closed loops, and has the function to prevent the release of fluid containing radioactive substances even if leak occurs in the primary cooling system. This system is mainly composed of carbon steel, and copper and its alloys are used for the sea water cooling. The auxiliary machines and coolers in the primary cooling system are made of stainless steel. Therefore, the rust prevention method used for this system must be effective for these metals or must not give harmful effect. As the rust prevention method for the plants in operation, chromic acid process and hydrazine process have been used, but the environmental pollution by chrome and the ammonia attack on copper alloys may occur. As the rust prevention process to improve these problems, LiOH method was examined. This cooling water system comprises four pumps, four water coolers, one surge tank, pipes and valves, and the water quality control in the system is explained. The rust prevention effect of LiOH for carbon steel, copper and its alloys was examined. Particular consideration is not required in the case of copper and its alloys, but pH higher than 12 is unsuitalbe. For the perfect rust prevention of carbon steel, the dissolved oxygen concentration must be less than 0.1 ppn, and pH must be more than 10. (Kako,I.)
In this activity, learners explore the design of tall structures such as skyscrapers and telecommunication towers. Learners work in teams to engineer the tallest tower they can build using just straws, pipe cleaners, and paperclips. The tower must be strong enough to support the weight of a golf ball for two minutes.
Frontal subduction of a cool surface water mass in the Gulf of Tehuantepec, Mexico
Directory of Open Access Journals (Sweden)
J. Brown
Full Text Available The southward wind events in the Gulf of Tehuantepec generate large warm eddies and strong offshore current jets that produce entrainment of subsurface waters into the upper ocean resulting in cool (dense water masses. Strong frontal features occur at the boundary between warm eddies and cool patches. An important fraction of the cool water is subducted beneath these eddies as intrapycnocline �lenses� (eddies within the boundary of a larger eddy. These small eddies are stable and interact with the larger one. Observational evidence of two such lenses is presented. Qualitative arguments based on observed flow and density fields, as well as vorticity arguments, confirm the existence of subduction processes. The magnitude of the subduction rate is estimated as large as 80 m d-1. A revised conceptual scheme of the eddy generating process is summarized as: a during the event the wind-induced offshore current entrains subsurface water in the central gulf, thus establishing the initial density gradient; b also during the event, the horizontal density gradient is maintained by horizontal warm water advection; c after the event a coastal jet separates from the west coast reaches the central gulf and spins up to form an anticyclone; d subduction due to intense convergence occurs where the warm coastal jet meets the cool water; e the �mature� warm eddy propagates offshore carrying a lens of cool subducted water within its boundary.
Water quality monitoring in MAPS open reservoir and its relevance to condenser cooling in FBTR
International Nuclear Information System (INIS)
An assessment of water quality of an open reservoir at Madras Atomic Power Station (MAPS), Kalpakkam was carried out. Results of the analyses showed significant increase in temperature, pH, dissolved oxygen (DO), chlorine demand, chlorophyll a and decrease in conductivity, nutrients, total hardness, calcium hardness and iron content from Palar water to reservoir water. The role of water quality changes in the reservoir is discussed in the context of its use for cooling. (author). 9 refs., 1 fig
Improving of the photovoltaic / thermal system performance using water cooling technique
Hussien, Hashim A.; Numan, Ali H.; Abdulmunem, Abdulmunem R.
This work is devoted to improving the electrical efficiency by reducing the rate of thermal energy of a photovoltaic/thermal system (PV/T).This is achieved by design cooling technique which consists of a heat exchanger and water circulating pipes placed at PV module rear surface to solve the problem of the high heat stored inside the PV cells during the operation. An experimental rig is designed to investigate and evaluate PV module performance with the proposed cooling technique. This cooling technique is the first work in Iraq to dissipate the heat from PV module. The experimental results indicated that due to the heat loss by convection between water and the PV panel's upper surface, an increase of output power is achieved. It was found that without active cooling, the temperature of the PV module was high and solar cells could only achieve a conversion efficiency of about 8%. However, when the PV module was operated under active water cooling condition, the temperature was dropped from 76.8�C without cooling to 70.1�C with active cooling. This temperature dropping led to increase in the electrical efficiency of solar panel to 9.8% at optimum mass flow rate (0.2L/s) and thermal efficiency to (12.3%).

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