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Microsoft Academic Search
High-rate anaerobic systems, such as the upflow anaerobic sludge blanket (UASB) reactors, are widely used in municipal and industrial wastewater treatment. Even though UASB reactors have several operational advantages, many industries are still reluctant to use them due to the fact that these reactors usually demand constant monitoring of effluent quality, excess sludge discharge and biogas production rate. Otherwise, they
R. M. Borges; C. J. Munaro; R. F. Gonńalves
Treatment of landfill leachate using sequencing batch and continuous flow upflow anaerobic sludge blanket (UASB) reactors
Treatment of municipal landfill leachate was investigated\\/compared using sequencing batch and continuous flow upflow anaerobic sludge blanket (UASB) reactors. All reactors were operated at organic loading rates (OLRs) between 0.6¢19.7 gCOD\\/l d. Performance of the continuous UASB and sequencing batch UASB reactors were very similar at low and intermediate OLRs. Continuous UASB reactors performed more favorably at the higher OLRs
K. J Kennedy; E. M Lentz
Anammox bacteria enrichment in upflow anaerobic sludge blanket (UASB) reactor
We investigated the anaerobic ammonium oxidation (anammox) reaction in a labscale upflow anaerobic sludge blanket (UASB) reactor.\\u000a Our aim was to detect and enrich the organisms responsible for the anammox reaction using a synthetic medium that contained\\u000a low concentrations of substrates (ammonium and nitrite). The reactor was inoculated with granular sludge collected from a\\u000a full-scale anaerobic digestor used for treating
Tran-Hung Thuan; Deok-Jin Jahng; Jin-Young Jung; Dong-Jin Kim; Won-Kyoung Kim; Young-Joo Park; Ji-Eun Kim; Dae-Hee Ahn
Start-up of a thermophilic upflow anaerobic sludge bed (UASB) reactor with mesophilic granular sludge
Fast start-up of thermophilic upflow anaerobic sludge bed (UASB) reactors was achieved at process temperatures of 46, 55 and 64░ C, using mesophilic granular sludge as inoculum and fatty acid mixtures as feed. The start-up was brought about by increasing the temperature of mesophilic UASB reactors in a single step, which initially led to a sharp drop in the methane
Jules B. van Lier; Katja C. F. Grolle; Alfons J. M. Stams; Everly Conway de Macario; Gatze Lettinga
Performance and behaviour of planted and unplanted units of a horizontal subsurface flow constructed wetland system treating municipal effluent from a UASB reactor.
A system composed of two horizontal subsurface flow constructed wetlands operating in parallel was evaluated for the post-treatment of UASB (upflow anaerobic sludge blanket) reactor effluent, for a population equivalent of 50 inhabitants per unit. One unit was planted with cattail (Typha latifolia) and the other was unplanted. The study was undertaken over a period of 4 years, comprising monitoring of influent and effluent constituents together with a full characterization of the behaviour of the units (tracer studies, mathematical modelling of chemical oxygen demand (COD) decay, characterization of solids in the filter medium). The mean value of the surface hydraulic load was 0.11 m(3)m(-2)d(-1), and the theoretical hydraulic retention time was 1.1 d in each unit. Using tracer tests with (82)Br, dispersion number (d) values of 0.084 and 0.079 for the planted and unplanted units were obtained, indicating low to moderate dispersion. The final effluent had excellent quality in terms of organic matter and suspended solids, but the system showed low capacity for nitrogen removal. Four-year mean effluent concentration values from the planted and unplanted units were, respectively: biochemical oxygen demand (BOD(5)): 25 and 23 mg L(-1); COD: 50 and 55 mg L(-1); total suspended solids (TSS): 9 and 9 mg L(-1); N-ammonia: 27 and 28 mg L(-1). The COD decay coefficient K for the traditional plug-flow model was 0.81 and 0.84 d(-1) for the planted and unplanted units. Around 80% of the total solids present in the filter medium were inorganic, and most of them were present in the interstices rather than attached to the support medium. As an overall conclusion, horizontal subsurface flow wetlands can be a very suitable post-treatment method for municipal effluents from anaerobic reactors. PMID:24135097
da Costa, Jocilene Ferreira; de Paoli, Andrķ Cordeiro; Seidl, Martin; von Sperling, Marcos
Kinetics of concentration decay of specific organic matter in UASB reactors operating with and without return of aerobic sludge.
This study aimed at assessing the influence of the return of excess aerobic sludge from a trickling filter (TF) upon the anaerobic digestion process in an upflow anaerobic sludge blanket (UASB) reactor, by evaluating its effect on the kinetics of the decay of specific organic matter (carbohydrates, proteins and lipids), as well as on the concentrations of volatile fatty acids in the UASB reactor. A pilot-scale UASB/TF system was used to perform the experiments, operating with (phase 2) and without (phase 1) excess sludge return from the TF to the UASB reactor. Sampling was carried out at different heights of the UASB reactor (0, 25, 125 and 225-cm height), and profile concentrations were determined for the following parameters: carbohydrates, proteins, lipids and volatile fatty acids. First-order kinetics showed the best fit to the decay of concentrations of carbohydrates, proteins, lipids and chemical oxygen demand (COD) in the UASB reactor. The parameters showing the best fit to the first-order kinetics were proteins and COD, during the sludge return phase. The occurrence of higher apparent reaction constants was further observed during the sludge return phase. For an influent COD concentration of 600 mg L-1 and hydraulic retention times of 2.1, 2.6 and 3.0 h in phase 1, the effluent COD concentrations were 125.3, 88.4 and 62.4 mg L-1, respectively, whereas in phase 2, the effluent COD concentrations were 75.5, 47.6 and 30.1 mg L-1, respectively. PMID:24956799
Pontes, P P; Chernicharo, C A L; Von Sperling, M
Heterogeneous Anaerobic Biofilm Reactor Models Application to UASB, EGSB and AFB Reactors
In a previous work, a methodology developed for modeling anaerobic fluidized bed (AFB) reactors was presented. The aim of this work is to extend this methodology for modeling upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors, and compare and discuss model hypotheses and simulation results. A set of experimental data obtained by Kato et al. (2003),
Mauren Fuentes; PĒo A. Aguirre; Nicolßs J. Scenna
Biosorption and biodegradation of pentachlorophenol (PCP) in an upflow anaerobic sludge blanket (UASB) reactor
In order to understand the fate of PCP in upflow anaerobic sludge blanket reactor (UASB) more completely, the sorption and\\u000a biodegradation of pentachlorophenol (PCP) by anaerobic sludge granules were investigated. The anaerobic granular sludge degrading\\u000a PCP was formed in UASB reactor, which was seeded with anaerobic sludge acclimated by chlorophenols. At the hydraulic retention\\u000a time (HRT) of 20¢22Āh, and PCP
Fen-Xia Ye; Ying Li
Enhanced reductive transformation of p-chloronitrobenzene in a novel bioelectrode-UASB coupled system.
The laboratory-scale upflow anaerobic sludge blanket (UASB) reactor equipped with a pair of bioelectrodes was established for the enhancement of p-chloronitrobenzene (p-ClNB) reductive transformation via the electrolysis. Results showed that a stable COD removal efficiency over 99% and high p-ClNB transformation rate of 0.328h(-1) were achieved in the bioelectrode-UASB coupled system with influent COD and p-ClNB loading rates of 2.1-4.2kgCODm(-3)d(-1) and 60gm(-3)d(-1), respectively. The bioelectrodes were supplied with a voltage of 2.5-5.0V and the effective current was above 2mA, which resulted in a continuous supply of H2. Compared with the traditional UASB reactor (R1), the production of H2 was promoted in the bioelectrode-UASB coupled system (R2), and was consumed as an internal electron donor for p-ClNB reductive transformation by anaerobic microbes simultaneously. Furthermore, the cyclic voltammetry curve (CV) analysis of biocathodes showed a positive shift in the reductive peak potential and a dramatic increase in the reductive peak current, which demonstrated the catalytic reduction of p-ClNB by biocathode in the combined system. PMID:24997372
Zhu, Liang; Gao, Kaituo; Qi, Jiaoqin; Jin, Jie; Xu, Xiangyang
Separation of solids and disinfection for agronomical use of the effluent from a UASB reactor.
The present work addresses the preparation of the effluent from a full-scale upflow anaerobic sludge blanket (UASB) reactor for drip irrigation of orange crops. The pilot plant included a lamella plate clarifier followed by a geo-textile blanket filter and a UV disinfection reactor. The clarifier operated with a surface load of 115 m(3)m(-2)d(-1), whereas the filter operated with 10 m(3)m(-2)d(-1). The UV reactor was an open-channel type and the effective dose was approximately 2.8 W h m(-3). The effluent of the UASB reactor received 0.5 mg L(-1) cationic polyelectrolyte before entering the high-rate clarifier. Suspended solids' concentrations and Escherichia coli and helminth egg's densities were monitored throughout the treatment system for 12 months. Results showed that the total suspended solids concentration in the filter effluent was lower than 7 mg L(-1) and helminth density was below 1.0 egg L(-1). The UV disinfection demonstrated the ability to produce a final effluent with E. coli density lower than 10(3)MPN/100 mL (MPN: most probable number) during the entire process. Thus, the World Health Organization standards for unrestricted crop use were met. Agronomic interest parameters were controlled and it was possible to identify the important contribution of treated sewage in terms of the main nutrients. PMID:24434964
Sundefeld Junior, G C; Piveli, R P; Cutolo, S A; Ferreira Filho, S S; Santos, J G
Characterization and removal of specific organic constituents in an UASB-trickling-filter system treating domestic wastewater.
This paper presents the characterization of specific organic constituents (carbohydrates, proteins and lipids) in raw sewage and in the anaerobic and aerobic effluents of a demo-scale (500 inhabitants) UASB- trickling-filter system. The evaluation of such parameters was carried out for two operating conditions, either without sludge recirculation (experiment I) from the trickling filter to the UASB reactor or with sludge recirculation (experiment II), for sludge thickening and stabilization, in the anaerobic reactor. The results showed that the contribution of acetic acid, carbohydrates, proteins and lipids amounted for approximately 70% of the total COD fed to the UASB during experiment I, whereas during experiment II these constituents amounted for only around 40% of the total COD. Although very high BOD and COD overall removal efficiencies were observed for the treatment system (around 90% and 80%, respectively), it was possible to infer that these efficiencies were mainly related to the removal of carbohydrates and lipids (around 80% removal), and of other non-identified constituents. The removal of proteins was much lower (around 50% removal), and the relative contribution of proteins to the total COD increased along the treatment course, being responsible for most of the residual COD of the treatment units. In the present system configuration, the UASB reactor played a major role in the removal of carbohydrates, whereas the trickling filter was very effective in the removal of lipids. The return of aerobic sludge for thickening and stabilization in the UASB reactor did not affect its performance. PMID:21780696
Pontes, PatrĒcia Proc¾pio; Chernicharo, Carlos Augusto de Lemos
Extracellular Polymeric Substances (EPS) in Upflow Anaerobic Sludge Blanket (UASB) Reactors Operated under High Salinity Conditions
Considering the importance of stable and well¢functioning granular sludge in anaerobic high rate reactors, a series of experiments were conducted to determine the production and composition of EPS in high sodium concentrations wastewaters pertaining to anaerobic granule properties. The UASB reactors were fed with either fully acidified substrate (FAS) consisting of an acetate medium (reactor R1) or partly acidified substrate
S. Ismail; Parra de la C. J; B. G. Temmink; Lier van J. B
Effects of organic, hydraulic and fat shocks on the performance of UASB reactors with intermittent operation
Three lab-scale UASB reactors operated at 35░C in an intermittent mode were subject to different step shocks: hydraulic, organic and feed fat content. The results show that the reactors have good resistance to the applied shocks and suggest that a feedless period is beneficial to the performance of the reactors, due to stabilisation of accumulated organic matter. Keywords COD conversion;
H. Nadais; I. Capela; L. Arroja; A. Duarte
Quantification of dissolved methane in UASB reactors treating domestic wastewater under different operating conditions.
This paper aimed at measuring the concentration of methane dissolved in effluents from different UASB reactors (pilot-, demo- and full-scale) treating domestic wastewater, in order to calculate the degree of saturation of such greenhouse gas and evaluate the losses of energetic potential in such systems. The results showed that methane saturation degrees, calculated according to Henry's law, varied from ?1.4 to 1.7 in the different reactors, indicating that methane was oversaturated in the liquid phase. The overall results indicated that the losses of dissolved methane in the anaerobic effluents were considerably high, varying from 36 to 41% of total methane generated in the reactor. These results show that there is considerable uncontrolled loss of methane in anaerobic wastewater treatment plants, implying the need of research on technologies aimed at recovering such energetic greenhouse gas. PMID:22156131
Souza, C L; Chernicharo, C A L; Aquino, S F
Integrated removal of nitrate and carbon in an upflow anaerobic sludge blanket (UASB) reactor: Operating performance
Denitrification and methanogenesis of a synthetic wastewater containing volatile fatty acids and nitrate were obtained in a single-stage process using an upflow anaerobic sludge blanket (UASB) reactor. The reactor was initially inoculated with methanogenic granular sludge and was gradually adapted to nitrate by increasing the nitrate concentration in the influent. Excess carbon not utilized for denitrification was converted to methane.
Hanne Vang Hendriksen; Birgitte Kiµr Ahring
Peptidolytic Microbial Community of Methanogenic Reactors from two Modified Uasbs of Brewery Industries
PubMed Central
We studied the peptide-degrading anaerobic communities of methanogenic reactors from two mesophilic full-scale modified upflow anaerobic sludge blanket (UASB) reactors treating brewery wastewater in Colombia. Most probable number (MPN) counts varied between 7.1 x 108 and 6.6 ū 109 bacteria/g volatile suspended solids VSS (Methanogenic Reactor 1) and 7.2 ū 106 and 6.4 ū 107 bacteria/g (VSS) (Methanogenic Reactor 2). Metabolites detected in the highest positive MPN dilutions in both reactors were mostly acetate, propionate, isovalerate and, in some cases, negligible concentrations of butyrate. Using the highest positive dilutions of MPN counts, 50 dominant strains were isolated from both reactors, and 12 strains were selected for sequencing their 16S rRNA gene based on their phenotypic characteristics. The small-subunit rRNA gene sequences indicated that these strains were affiliated to the families Propionibacteriaceae, Clostridiaceae and Syntrophomonadaceae in the low G + C gram-positive group and Desulfovibrio spp. in the class ?-Proteobacteria. The main metabolites detected in the highest positive dilutions of MPN and the presence of Syntrophomonadaceae indicate the effect of the syntrophic associations on the bioconversion of these substrates in methanogenic reactors. Additionally, the potential utilization of external electron acceptors for the complete degradation of amino acids by Clostridium strains confirms the relevance of these acceptors in the transformation of peptides and amino acids in these systems.
Diaz, C.; Baena, S.; Patel, B.K.C.; Fardeau, M.L.
Anaerobic granule formation and tetrachloroethylene (TCE) removal in an upflow anaerobic sludge blanket (UASB) reactor
The granulation process was examined using synthetic wastewater containing tetrachloroethylene (TCE) in a 2 liters laboratory upflow anaerobic sludge blanket (UASB) reactor. The anaerobic biotransformation of TCE was investigated during the granulation process by reducing the HRT and increasing the chemical oxygen demand (COD) and TCE loadings. Anaerobic unacclimated sludge and glucose were used as seed and primary substrate, respectively.
Delia Teresa Sponza
Ozone Application for the Improvement of UASB Reactor Effluent. II. Toxicity Evaluation
In order to improve the effluent from domestic sewage treatment through an anaerobic process in an upflow anaerobic sludge blanket reactor (UASB), CETESB - The Environmental Protection Agency for Sao Paulo State, and FILSAN - Equipamentos e Sistemas S\\/A, developed a joint program to study the effectiveness of ozonation of the effluent as a post-treatment process. As the effluents treated
R. P. A. Ara·jo; T. M. T. Gasi; E. Gherardi-Goldstein; L. A. V. Amaral; R. Francisco
Extracellular polymeric substances (EPS) in upflow anaerobic sludge blanket (UASB) reactors operated under high salinity conditions
Considering the importance of stable and well-functioning granular sludge in anaerobic high-rate reactors, a series of experiments were conducted to determine the production and composition of EPS in high sodium concentration wastewaters pertaining to anaerobic granule properties. The UASB reactors were fed with either fully acidified substrate (FAS) consisting of an acetate medium (reactor R1) or partly acidified substrate (PAS)
S. B. Ismail; C. J. de La Parra; H. Temmink; J. B. van Lier
Comparison of UASB and EGSB reactors performance, for treatment of raw and deoiled palm oil mill effluent (POME).
Anaerobic digestion of palm oil mill effluent (POME) and deoiled POME was investigated both in batch assays and continuous reactor experiments using up-flow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors. The methane potential determined from batch assays of POME and deoiled POME was 503 and 610 mL-CH(4)/gVS-added, respectively. For the treatment of POME in continuously fed reactors, both in UASB and EGSB reactors more than 90% COD removal could be obtained, at HRT of 5 days, corresponding to OLR of 5.8 gVS/(L-reactor.d). Similar methane yields of 436-438 mL-CH(4)/gVS-added were obtained for UASB and EGSB respectively. However, for treatment of deoiled POME, both UASB and EGSB reactors could operate at lower OLR of 2.6 gVS/(L-reactor.d), with the methane yield of 600 and 555 mL-CH(4)/gVS-added for UASB and EGSB, respectively. The higher methane yield achieved from the deoiled POME was attributed to lower portion of biofibers which are more recalcitrant compared the rest of organic matter in POME. The UASB reactor was found to be more stable than EGSB reactor under the same OLR, as could be seen from lower VFA concentration, especially propionic acid, compared to the EGSB reactor. PMID:21377272
Fang, Cheng; O-Thong, Sompong; Boe, Kanokwan; Angelidaki, Irini
Performance of plastic- and sponge-based trickling filters treating effluents from an UASB reactor.
The paper compares the performance of two trickling filters (TFs) filled with plastic- or sponge-based packing media treating the effluent from an upflow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated with an organic loading rate (OLR) of 1.2 kgCOD m(-3) d(-1), and the OLR applied to the TFs was 0.30-0.65 kgCOD m(-3) d(-1) (COD: chemical oxygen demand). The sponge-based packing medium (Rotosponge) gave substantially better performance for ammonia, total-N, and organic matter removal. The superior TF-Rotosponge performance for NH(4)(+)-N removal (80-95%) can be attributed to its longer biomass and hydraulic retention times (SRT and HRT), as well as enhancements in oxygen mass transfer by dispersion and advection inside the sponges. Nitrogen removals were significant (15 mgN L(-1)) in TF-Rotosponge when the OLRs were close to 0.75 kgCOD m(-3) d(-1), due to denitrification that was related to solids hydrolysis in the sponge interstices. For biochemical oxygen demand removal, higher HRT and SRT were especially important because the UASB removed most of the readily biodegradable organic matter. The new configuration of the sponge-based packing medium called Rotosponge can enhance the feasibility of scaling-up the UASB/TF treatment, including when retrofitting is necessary. PMID:23416595
Almeida, P G S; Marcus, A K; Rittmann, B E; Chernicharo, C A L
Anaerobic granule development for removal of pentachlorophenol in an upflow anaerobic sludge blanket (UASB) reactor
The granulation process using synthetic wastewater containing pentachlorophenol (PCP) in four 1.1l laboratory scale upflow anaerobic sludge blanket (UASB) reactors was studied, and the anaerobic biotransformation of PCP during the granulation process investigated. After 110 days granular sludge was developed and up to 160 and 180mg\\/l of PCP was added into the reactors R1 and R2, respectively, when they were
Fen-Xia Ye; Dong-Sheng Shen; Xiao-Shan Feng
Mathematical modeling of high-rate Anammox UASB reactor based on granular packing patterns.
A novel mathematical model was developed to estimate the volumetric nitrogen conversion rates of a high-rate Anammox UASB reactor based on the packing patterns of granular sludge. A series of relationships among granular packing density, sludge concentration, hydraulic retention time and volumetric conversion rate were constructed to correlate Anammox reactor performance with granular packing patterns. It was suggested that the Anammox granules packed as the equivalent simple cubic pattern in high-rate UASB reactor with packing density of 50-55%, which not only accommodated a high concentration of sludge inside the reactor, but also provided large pore volume, thus prolonging the actual substrate conversion time. Results also indicated that it was necessary to improve Anammox reactor performance by enhancing substrate loading when sludge concentration was higher than 37.8 gVSS/L. The established model was carefully calibrated and verified, and it well simulated the performance of granule-based high-rate Anammox UASB reactor. PMID:23434474
Tang, Chong-Jian; He, Rui; Zheng, Ping; Chai, Li-Yuan; Min, Xiao-Bo
Effect of pentachlorophenol and chemical oxygen demand mass concentrations in influent on operational behaviors of upflow anaerobic sludge blanket (UASB) reactor
Upflow anaerobic sludge blanket (UASB) reactor that was seeded with anaerobic sludge acclimated to chlorophenols was used to investigate the feasibility of anaerobic biotreatment of synthetic wastewater containing pentachlorophenol (PCP) with additional sucrose as carbon source. Two sets of UASB reactors were operated at one time. But the seeded sludge for the two reactors was different and Reactor I was
Dong-Sheng Shen; Ruo He; Xin-Wen Liu; Yan Long
Biosorption and biodegradation of pentachlorophenol (PCP) in an upflow anaerobic sludge blanket (UASB) reactor.
In order to understand the fate of PCP in upflow anaerobic sludge blanket reactor (UASB) more completely, the sorption and biodegradation of pentachlorophenol (PCP) by anaerobic sludge granules were investigated. The anaerobic granular sludge degrading PCP was formed in UASB reactor, which was seeded with anaerobic sludge acclimated by chlorophenols. At the hydraulic retention time (HRT) of 20-22 h, and PCP loading rate of 200-220 mg l(-1) d(-1), UASB reactor exhibited good performance in treating wastewater which containing 170-180 mg l(-1) PCP and the PCP removal rate of 99.5% was achieved. Sequential appearance of tetra-, tri-, di-, and mono-chlorophenol was observed in the reactor effluent after 20 mg l(-1) PCP introduction. Sorption and desorption of PCP on the anaerobic sludge granules were all fitted to the Freundlich isotherm equation. Sorption of PCP was partly irreversible. The Freundlich equation could describe the behavior of PCP amount sorbed by granular sludge in anaerobic reactor reasonably well. The results demonstrated that the main mechanism leading to removal of PCP on anaerobic granular sludge was biodegradation, not sorption or volatization. PMID:17146612
Ye, Fen-Xia; Li, Ying
Pathogen removal efficiency from UASB + BF effluent using conventional and UV post-treatment systems.
The aim of this study was to verify the efficiency of removal of microorganisms in effluents of a Wastewater Treatment Plant (WWTP) comprising an association of a UASB reactor followed by three submerged aerated biofilters (BAF) and one tertiary filter. The WWTP designed to treat domestic wastewater from a population of 1,000 inhabitants showed high removal efficiency for organic matter and suspended solids. Helminth eggs were also efficiently removed from the tertiary effluent and were found in the sludge from the UASB reactor; however, removal of bacteria in this system was very low. To enhance the efficiency of the system, the effluent from tertiary filters was submitted to UV disinfection in a real scale reactor. Our results showed that UV irradiation was very effective at lowering the concentrations of E. coli, thermotolerant coliforms and coliphages to acceptable levels for agricultural reuse. Salmonella spp. and helminth eggs were seeded into the tertiary effluent before passing through the UV reactor. Salmonella was not found in the final effluent, but helminth eggs were not completely inactivated by UV irradiation and viable eggs were detected after 28 d of incubation. PMID:15318478
Keller, R; Passamani-Franca, R F; Passamani, F; Vaz, L; Cassini, S T; Sherrer, N; Rubim, K; Sant'Ana, T D; Gonńalves, R F
Treatment of starch wastewater using UASB reactor with hydraulic circulation and biomass screen
Hydraulic circulation system and biomass screen plate were used to modify a labortary-scale UASB for higher upflow velocity and biomass. The effects of influent concentration, hydraulic retention time, organic volume loading rate and upflow velocity on removal of organic matter from starch wastewater were investigated. The results revealed that biomass screen and hydraulic circulation system accelerated the growth of the
Guizhang Li; Xiumei Ma; Jiancheng Tu
Performance of upflow anaerobic sludge blanket (UASB) reactor treating wastewaters containing carbon tetrachloride
The anaerobic biodegradation of carbon tetrachloride (CT) was investigated during the granulation process by reducing the hydraulic retention time, increasing the chemical oxygen demand (COD) and CT loadings in a 2l laboratory-scale upflow anaerobic sludge blanket (UASB) reactor. Anaerobic unacclimated sludge and glucose were used as seed and primary substrate, respectively. Granules were developed 4 weeks after start-up, which grew
The anaerobic biotransformation of TCE was investigated during the granulation process by reducing the HRT and increasing the chemical oxygen demand (COD) and TCE loadings in a 2Āl laboratory-scale upflow anaerobic sludge blanket (UASB) reactor. Anaerobic unacclimated sludge and glucose were used as seed and primary substrate, respectively. Initial granules were developed after 1.5 months of start-up, which grew at
Continuous detoxification, transformation, and degradation of nitrophenols in upflow anaerobic sludge blanket (UASB) reactors
The anaerobic transformation and degradation of nitrophenols by granular sludge was investigated in upflow anaerobic sludge blanket (UASB) reactors continuously fed with a volatile fatty acid (VFA) mixture as the primary substrate. During the start-up, subtoxic concentrations of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), and 2, 4-dinitrophenol (2, 4-DNP) were utilized. 4-NP and 2, 4-DNP were readily converted to the corresponding aromatic
B. A. Donlon; E. Razo-Flores; G. Lettinga; J. A. Field
Methane production by treating vinasses from hydrous ethanol using a modified UASB reactor
Background A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. Results The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m3-day, achieving a methane yield of 0.263 m3/kg CODadded and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. Conclusions The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production. Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production.
Dynamics of extracellular polymeric substances in UASB and EGSB reactors treating medium and low concentrated wastewaters
In this work the dynamic study of EPS (Extracellular Polymeric Substances) concentration and distribution during the operation of two different reactor configurations (UASB and EGSB) is presented, treating medium (5 g COD\\/l) and low-concentrated (0.5 g COD\\/l) wastewater. Medium-concentrated wastewater was supplied for granules maturation as well as for stabilisation of the process. The effect of substrate change on granule
A. Pu±al; S. Brauchi; J. G. Reyes; R. Chamy
Mathematical modeling of upflow anaerobic sludge blanket (UASB) reactor treating domestic wastewater.
Although the upflow anaerobic sludge blanket (UASB) reactor has been widely applied for domestic wastewater treatment in many developing countries, there is no sufficient mathematical model for proper design and operation of the reactor. An empirical model based on non-linear regression was developed to represent the physical and chemical removal of suspended solids (SS) in the reactor. Moreover, a simplified dynamic model based on ADM1 and the empirical model for SS removal was developed for anaerobic digestion of the entrapped SS and dissolved matter in the wastewater. The empirical model showed that effluent suspended chemical oxygen demand (COD(ss)) concentration is directly proportional to the influent COD(ss) concentration and inversely proportional to both the hydraulic retention time (HRT) of the reactor and wastewater temperature. For obtaining sufficient COD(ss) removal, the HRT of the UASB reactor must be higher than 4 h, and higher HRT than 12 h slightly improved COD(ss) removal. The dynamic model results showed that the required time for filling the reactor with sludge mainly depends on influent total chemical oxygen demand (COD(t)) concentration and HRT. The influent COD(t) concentration, HRT and temperature play a crucial role on the performance of the reactor. The results indicated that shorter HRT is needed for optimization of COD(t) removal, as compared with optimization of COD(t) conversion to methane. Based on the model results, the design HRT of the UASB reactor should be selected based on the optimization of wastewater conversion and minimization of biodegradable SS accumulation in the sludge bed, not only based on COD removal, to guarantee a stable reactor performance. PMID:23128617
Elmitwalli, Tarek
Effect of shock and mixed nitrophenolic loadings on the performance of UASB reactors
The effect of nitrophenolic shock loads on the performance of three bench-scale upflow anaerobic sludge blanket (UASB) reactors was studied using synthetic wastewater. Reactors R1, R2 and R3 were fed with 30mg\\/L concentration of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP) and 2,4-dinitrophenol (2,4-DNP), respectively, along with methanol (COD=2000mg\\/L), sodium nitrate (NO3?-N=200mg\\/L), and other nutrients. The reactors were in continuous operation for more
Khursheed Karim; S. K. Gupta
Performance assessment of different STPs based on UASB followed by aerobic post treatment systems
This paper present the experiences gained from the study of ten up flow anaerobic sludge blanket (UASB) based sewage treatment plants (STPs) of different cities of India. Presently 37 UASB based STPs were under operation and about 06 UASB based STPs are under construction and commissioning phase at different towns. The nature of sewage significantly varied at each STP. Two STP were receiving sewage with high sulfate and heavy metals due to the mixing of industrial waste. The treatment performance of all UASB reactors in terms of BOD, COD and TSS were observed between 55 to 70% respectively. The post treatment units down flow hanging sponge (DHS) and Aeration followed by activated sludge process (ASP) at two STPs were performing well and enable to achieve the required disposal standards. Results indicate the effluent quality in terms of BOD and SS were less than 30 and 50Āmg/L and well below the discharging standards.
Performance assessment of different STPs based on UASB followed by aerobic post treatment systems.
This paper present the experiences gained from the study of ten up flow anaerobic sludge blanket (UASB) based sewage treatment plants (STPs) of different cities of India. Presently 37 UASB based STPs were under operation and about 06 UASB based STPs are under construction and commissioning phase at different towns. The nature of sewage significantly varied at each STP. Two STP were receiving sewage with high sulfate and heavy metals due to the mixing of industrial waste. The treatment performance of all UASB reactors in terms of BOD, COD and TSS were observed between 55 to 70% respectively. The post treatment units down flow hanging sponge (DHS) and Aeration followed by activated sludge process (ASP) at two STPs were performing well and enable to achieve the required disposal standards. Results indicate the effluent quality in terms of BOD and SS were less than 30 and 50Āmg/L and well below the discharging standards. PMID:24468307
Khan, Abid Ali; Gaur, Rubia Zahid; Mehrotra, Indu; Diamantis, Vasileios; Lew, Beni; Kazmi, Absar Ahmad
Understanding the removal mechanisms of PPCPs and the influence of main technological parameters in anaerobic UASB and aerobic CAS reactors.
The removal of 16 Pharmaceutical and Personal Care Products (PPCPs) were studied in a conventional activated sludge (CAS) unit and an upflow anaerobic sludge blanket (UASB) reactor. Special attention was paid to each biomass conformation and activity as well as to operational conditions. Biodegradation was the main PPCP removal mechanism, being higher removals achieved under aerobic conditions, except in the case of sulfamethoxazole and trimetrophim. Under anaerobic conditions, PPCP biodegradation was correlated with the methanogenic rate, while in the aerobic reactor a relationship with nitrification was found. Sorption onto sludge was influenced by biomass conformation, being only significant for musk fragrances in the UASB reactor, in which an increase of the upward velocity and hydraulic retention time improved this removal. Additionally, PPCP sorption increased with time in the UASB reactor, due to the granular biomass structure which suggests the existence of intra-molecular diffusion. PMID:25010455
Alvarino, T; Suarez, S; Lema, J M; Omil, F
Dispersion and treatment performance analysis of an UASB reactor under different hydraulic loading rates.
Mixing and transport phenomena affect the efficiency of all bioreactor configurations. An even mixing pattern at the macro-level is desirable to provide good conditions for substrate transport to, and from, the microbial aggregates. The state of segregation of particulate material in the reactor is also important. The production of biogas in anaerobic reactors is another factor that affects mixing intensity and hence the interactions between the liquid, solid and gaseous phases. The CSTR model with some degree of short-circuiting, dead zones and bypassing flows seems to describe the overall hydrodynamics of UASBs. However, few data are available in the literature for full-scale reactors that relate process performance to mixing characteristics. Dispersion studies using LiCl were done for four hydraulic loading rates on a full-scale UASB treating domestic wastewater in Ginebra, Valle del Cauca, southwest Colombia. COD, TSS, and Settleable Solids were used to evaluate the performance of organic matter removal. The UASB showed a complete mixing pattern for hydraulic loading rates close to the design value (i.e. Q = 10-13l s(-1) and HRT=8-6 h). Gross mixing distortions and localised stagnant zones, short-circuiting and bypass flows were found in the sludge bed and blanket zones for both extreme conditions (underloading and overloading). The liquid volume contained below the gas-liquid-solid separator was found to contribute to the overall stagnant volume, particularly when the reactor was underloaded. The removal of organic matter showed a log-linear correlation with the dispersion number. PMID:16405944
Pe±a, M R; Mara, D D; Avella, G P
Methane and hydrogen sulfide emissions in UASB reactors treating domestic wastewater.
The release of CH(4) and H(2)S in UASB reactors was evaluated with the aim to quantify the emissions from the liquid surfaces (three-phase separator and settler compartment) and also from the reactor's discharge hydraulic structures. The studies were carried out in two pilot- (360 L) and one demo-scale (14 m(3)) UASB reactors treating domestic wastewater. As expected, the release rates were much higher across the gas/liquid interfaces of the three-phase separators (5.4-9.7 kg CH(4) m(-2) d(-1) and 23.0-35.8 g S m(-2) d(-1)) as compared with the quiescent settler surfaces (11.0-17.8 g CH(4) m(-2) d(-1) and 0.21 to 0.37 g S m(-2) d(-1)). The decrease of dissolved methane and dissolved hydrogen sulfide was very large in the discharging hydraulic structures very close to the reactor (>60 and >80%, respectively), largely due to the loss to the atmosphere, indicating that the concentration of these compounds will probably fall to values close to zero in the near downstream structures. The emission factors due to the release of dissolved methane in the discharge structure amounted to around 0.040 g CH(4) g COD(infl)(-1) and 0.060 g CH(4) g COD(rem)(-1), representing around 60% of the methane collected in the three-phase separator. PMID:22437020
Souza, C L; Chernicharo, C A L; Melo, G C B
Post-treatment of UASB effluent in an expanded granular sludge bed reactor type using flocculent sludge
The performance of an EGSB (expanded granular sludge bed) reactor type using flocculent sludge was evaluated for the post-treatment of effluent from UASB reactor treating domestic sewage. A pilot-scale 157.5-L EGSB reactor was monitored during a 331-day period. The original concept of the EGSB reactor was based on granular sludge use and by applying of high upflow liquid velocities (Vup).
M. T. Kato; L. Florencio; R. F. M. Arantes
A novel process using enhanced acidification and a UASB reactor for biomethanation of vegetable market waste.
The processing of solid vegetable market waste was attempted in a two-stage digester. Initially, for the hydrolysis and acidification of waste, enhanced extraction process was carried out by continuous sprinkling of water over the bed of waste in a mild steel 100 1 solid bed digester. The leachate obtained after completion of acidification phase was further treated in 24.6 1 UASB reactor for biogas production. The effect of waste-liquid ratio, dilution and sprinkling rate on the digestion of waste were studied. A high strength leachate, with a COD of 25,298 mg l(-1) and total volatile fatty acids concentration of 11.3 g l(-1), was obtained as a result of hydrolysis and acidification in a very short retention time of 40 h. The COD reduction of 94% was achieved during UASB reactor operation at organic loading rate of 19.6 kg COD m day(-3). A minimum hydraulic retention time of 16 h was achieved. PMID:11720263
Rajeshwari, K V; Lata, K; Pant, D C; Kishore, V V
The settling characteristics and mean settling velocity of granular sludge in upflow anaerobic sludge blanket (UASB)-like reactors
Mean settling velocity of granular sludge in full-scale UASB (upflow anaerobic sludge blanket) and EGSB (expanded granular sludge bed) reactors was evaluated by settling column tests, and a settling velocity model based on the experimental results and available literature data was developed. It is concluded that the settling velocity should be calculated by the Allen formula, because the settling process
Yong-hong Liu; Yan-ling He; Shu-cheng Yang; Yao-zhong Li
Enhancement of granule formation and sludge retainment for tetrachloroethylene (TCE) removal in an upflow anaerobic sludge blanket (UASB) reactor
Tetrachloroethylene (TCE) in wastewater was effectively removed at 35 ░C over 200 days in an upflow anaerobic sludge blanket (UASB) reactor in order to investigate the formation of TCE degrading granules. Anaerobic unacclimated sludge and glucose were used as seed and primary substrate, respectively. TCE degrading massive initial granules were developed after 1.5 months of start-up, which grew at an
Comparison of UASB and EGSB reactors performance, for treatment of raw and deoiled palm oil mill effluent (POME)
Anaerobic digestion of palm oil mill effluent (POME) and deoiled POME was investigated both in batch assays and continuous reactor experiments using up-flow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors. The methane potential determined from batch assays of POME and deoiled POME was 503 and 610mL-CH4\\/gVS-added, respectively. For the treatment of POME in continuously fed reactors,
Cheng Fang; Sompong O-Thong; Kanokwan Boe; Irini Angelidaki
Performance of anammox UASB reactor treating low strength wastewater under moderate and low temperatures.
An integrated approach to enhance and maintain high anammox activity and abundance in an upflow anaerobic sludge blanket (UASB) treating low strength wastewater under moderate and low temperatures was developed. A quantitative PCR assay showed the abandance of anammox bacteria to be 1.68▒0.08ū10(9) copies/ml in mixed liquor when the temperature was 30 ░C and was maintained at the level of 1.93▒0.41ū10(9) copies/ml in mixed liquor at 16 ░C. A nitrogen removal rate (NRR) of up to 5.72 kg N/m3/d was achieved with a hydraulic retention time (HRT) of 0.12 h at 30 ░C, while nitrite and ammonium removal efficiencies were 94.35% and 92.81%, respectively. NRR decreased with a decrease in temperature and was maintained at 2.28 kg N/m3/d with an HRT of 0.28 h when at 16 ░C, while nitrite and ammonium removal efficiencies were 92.31% and 78.45%, respectively. The emission rate of the greenhouse gas N2O was below 0.006% of the NRR in the anammox UASB reactor treating low strength wastewater. PMID:23313946
Ma, Bin; Peng, Yongzhen; Zhang, Shujun; Wang, Junmin; Gan, Yiping; Chang, Jiang; Wang, Shuying; Wang, Shanyun; Zhu, Guibing
Effects of high calcium concentrations on the development of methanogenic sludge in upflow anaerobic sludge bed (UASB) reactors
The feasibility of anaerobic treatment of wastewaters with a high calcium content (600¢1200mgCa2+.l?1) was studied. The influence of the amount of precipitation and the influence of differences in biomass yield were investigated on the development of anaerobic sludge. The experiments were performed in lab scale Upflow Anaerobic Sludge Blanket (UASB) reactors, inoculated with crushed granular sludge. Four reactors were operated
E. P. A. van Langerak; G. Gonzalez-Gil; A. van Aelst; J. B. van Lier; H. V. M. Hamelers; G. Lettinga
Heavy metal removal in an UASB-CW system treating municipal wastewater.
The objective of the present study was to investigate for the first time the long-term removal of heavy metals (HMs) in a combined UASB-CW system treating municipal wastewater. The research was carried out in a field pilot plant constituted for an up-flow anaerobic sludge bed (UASB) digester as a pretreatment, followed by a surface flow constructed wetland (CW) and finally by a subsurface flow CW. While the UASB showed (pseudo) steady state operational conditions and generated a periodical purge of sludge, CWs were characterised by the progressive accumulation and mineralisation of retained solids. This paper analyses the evolution of HM removal from the water stream over time (over a period of 4.7 year of operation) and the accumulation of HMs in UASB sludge and CW sediments at two horizons of 2.7 and 4.0 year of operation. High removal efficiencies were found for some metals in the following order: Sn > Cr > Cu > Pb > Zn > Fe (63-94%). Medium removal efficiencies were registered for Ni (49%), Hg (42%), and Ag (40%), and finally Mn and As showed negative percentage removals. Removal efficiencies of total HMs were higher in UASB and SF units and lower in the last SSF unit. PMID:23942017
de la Varga, D; DĒaz, M A; Ruiz, I; Soto, M
Studies on adsorption, desorption and biodegradation of pentachlorophenol by the anaerobic granular sludge in an upflow anaerobic sludge blanket (UASB) reactor
PCP-degrading anaerobic granular sludge could be formed in an upflow anaerobic sludge blanket (UASB) reactor that was seeded with anaerobic sludge acclimated to chlorophenol. When hydraulic retention time (HRT) was 20¢22h and PCP loading rate was 200¢220mgL?1d?1, the wastewater containing170¢180mgL?1 PCP could be treated effectively in UASB reactor, and PCP removal rate reached up to 99.5%. PCP adsorption and desorption
Dong-Sheng Shen; Xin-Wen Liu; Yong-Hua He
A novel UASB¢MFC¢BAF integrated system for high strength molasses wastewater treatment and bioelectricity generation
An up-flow anaerobic sludge blanket reactor¢microbial fuel cell¢biological aerated filter (UASB¢MFC¢BAF) system was developed for simultaneous bioelectricity generation and molasses wastewater treatment in this study. The maximum power density of 1410.2mW\\/m2 was obtained with a current density of 4947.9mA\\/m2 when the high strength molasses wastewater with chemical oxygen demand (COD) of 127,500mg\\/l was employed as the influent. The total COD,
Baogang Zhang; Huazhang Zhao; Shungui Zhou; Chunhong Shi; Chao Wang; Jinren Ni
SciTech Connect
The anaerobic transformation and degradation of nitrophenols by granular sludge was investigated in upflow anaerobic sludge blanket (UASB) reactors continuously fed with a volatile fatty acid (VFA) mixture as the primary substrate. During the start-up, subtoxic concentrations of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), and 2, 4-dinitrophenol (2, 4-DNP) were utilized. 4-NP and 2, 4-DNP were readily converted to the corresponding aromatic amine; whereas 2-NP was converted to nonaromatic products via intermediate formation of 2-aminophenol (2-AP). These conversions led to a dramatic detoxification of the mononitrophenols because the reactors treated the nitrophenolics at the concentrations which were over 25 times higher than those that caused severe inhibition. VFA removal efficiencies greater than 99% were achieved in both reactors at loading rates greater than 11.4 g COD per liter of reactor volume per day even at volumetric loading of mononitrophenols up to 910 mg/L {center_dot} d. The sludges obtained from each of the reactors at the end of the continuous experiments were assayed for their specific nitrophenol reducing activity in the presence of different primary substrates. Reduction rates of 45 and 26 mg/g volatile suspended solids per day were observed for 2-NP and 4-NP, respectively, when utilizing the VFA mixture as primary substrate.
Donlon, B.A.; Razo-Flores, E.; Lettinga, G.; Field, J.A. [Wageningen Agricultural Univ. (Netherlands). Dept. of Environmental Technology] [Wageningen Agricultural Univ. (Netherlands). Dept. of Environmental Technology
Thermophilic anaerobic digestion of Lurgi coal gasification wastewater in a UASB reactor.
Lurgi coal gasification wastewater (LCGW) is a refractory wastewater, whose anaerobic treatment has been a severe problem due to its toxicity and poor biodegradability. Using a mesophilic (35▒2░C) reactor as a control, thermophilic anaerobic digestion (55▒2░C) of LCGW was investigated in a UASB reactor. After 120 days of operation, the removal of COD and total phenols by the thermophilic reactor could reach 50-55% and 50-60% respectively, at an organic loading rate of 2.5 kg COD/(m(3) d) and HRT of 24 h; the corresponding efficiencies were both only 20-30% in the mesophilic reactor. After thermophilic digestion, the wastewater concentrations of the aerobic effluent COD could reach below 200 mg/L compared with around 294 mg/L if mesophilic digestion was done and around 375 mg/L if sole aerobic pretreatment was done. The results suggested that thermophilic anaerobic digestion improved significantly both anaerobic and aerobic biodegradation of LCGW. PMID:21112778
Wang, Wei; Ma, Wencheng; Han, Hongjun; Li, Huiqiang; Yuan, Min
Effect of addition of an exogenous exopolymeric substance in UASB and EGSB reactors.
The operation of two different reactor configurations (UASB and EGSB), while treating medium and low concentrated wastewater (MCW and LCW, respectively), was studied. The MCW (5 g COD/l) was initially supplied for reactor start up and granule maturation, being subsequently changed to the LCW (0.5 g COD/I), with which led the reactors to an unstable state associated with the deterioration of granule characteristics, in terms of extracellular polymeric substances (EPS) content and composition. The addition of pectin as an exogenous EPS was considered as a way to directly act on granule characteristics and its effect was studied by monitoring the operational parameters as well as by following the EPS content and composition within granules and the dynamics of microbial populations. The effect of adding pectin led to a significant recuperation of the operational performance in both reactors, associated with the increase in Archaea relative abundance, this likely related to the major presence of Methanosaeta-like microorganisms in granules with higher activity and stability. PMID:16939080
Vivanco, E; Pu±al, A; Chamy, R
Start-up characteristics of a granule-based anammox UASB reactor seeded with anaerobic granular sludge.
The granulation of anammox sludge plays an important role in the high nitrogen removal performance of the anammox reactor. In this study, anaerobic granular sludge was selected as the seeding sludge to start up anammox reactor in order to directly obtain anammox granules. Results showed that the anammox UASB reactor was successfully started up by inoculating anaerobic granular sludge, with substrate capacity of 4435.2 mg/(L Ę d) and average ammonium and nitrite removal efficiency of 90.36% and 93.29%, respectively. During the start-up course, the granular sludge initially disintegrated and then reaggregated and turned red, suggesting the high anammox performance. Zn-Fe precipitation was observed on the surface of granules during the operation by SEM-EDS, which would impose inhibition to the anammox activity of the granules. Accordingly, it is suggested to relatively reduce the trace metals concentrations, of Fe and Zn in the conventional medium. The findings of this study are expected to be used for a shorter start-up and more stable operation of anammox system. PMID:24455691
Xiong, Lei; Wang, Yun-Yan; Tang, Chong-Jian; Chai, Li-Yuan; Xu, Kang-Que; Song, Yu-Xia; Ali, Mohammad; Zheng, Ping
Start-Up Characteristics of a Granule-Based Anammox UASB Reactor Seeded with Anaerobic Granular Sludge
The granulation of anammox sludge plays an important role in the high nitrogen removal performance of the anammox reactor. In this study, anaerobic granular sludge was selected as the seeding sludge to start up anammox reactor in order to directly obtain anammox granules. Results showed that the anammox UASB reactor was successfully started up by inoculating anaerobic granular sludge, with substrate capacity of 4435.2?mg/(LĘd) and average ammonium and nitrite removal efficiency of 90.36% and 93.29%, respectively. During the start-up course, the granular sludge initially disintegrated and then reaggregated and turned red, suggesting the high anammox performance. Zn-Fe precipitation was observed on the surface of granules during the operation by SEM-EDS, which would impose inhibition to the anammox activity of the granules. Accordingly, it is suggested to relatively reduce the trace metals concentrations, of Fe and Zn in the conventional medium. The findings of this study are expected to be used for a shorter start-up and more stable operation of anammox system.
Wang, Yun-Yan; Tang, Chong-Jian; Chai, Li-Yuan; Xu, Kang-Que; Song, Yu-Xia
Effects of bioaugmentation strategies in UASB reactors with a methanogenic consortium for removal of phenolic compounds
The removal of phenol, ortho- (op) and para- (p-) cresol was studied with two series of UASB reactors using unacclimatized granular sludges bioaugmented with a consortium enriched against these substances. The parameters studied were the amount of inoculum added to the sludges and the method of immobilization of the inoculum. Two methods were used, adsorption to the biomass or encapsulation with calcium alginate beads. In the bioaugmentation by adsorption experiment, and with a 10% inoculum, complete phenol removal was obtained after 36 d, while 178 d were required in the control reactor. For p-cresol, 95% removal was obtained in the bioaugmented reactor on day 48 while 60 d were required to achieve 90% removal in the control reactor. For o-cresol, the removals were only marginally better with the bioaugmented reactors. Tests performed with the reactors biomass under non-limiting substrate concentrations showed that the specific activities of the bioaugmented biomasses were larger than the original biomass for phenol, and p-cresol even after 276 of operations, showing that the inoculum bacteria successfully colonized the sludge granules. Immobilization of the inoculum by encapsulation in calcium alginate beads, was performed with 10% of the inoculum. Results showed that the best activities were obtained when the consortium was encapsulated alone and the beads added to the sludges. This reactor presented excellent activity and the highest removal of the various phenolic compounds a few days after start-up. After 90 d, a high-phenolic compounds removal was still observed, demonstrating the effectiveness of the encapsulation technique for the start-up and maintenance of high-removal activities.
Hajji, K.T.; Lepine, F.; Bisaillon, J.G.; Beaudet, R.; Hawari, J.; Guiot, S.R.
A novel UASB-MFC-BAF integrated system for high strength molasses wastewater treatment and bioelectricity generation.
An up-flow anaerobic sludge blanket reactor-microbial fuel cell-biological aerated filter (UASB-MFC-BAF) system was developed for simultaneous bioelectricity generation and molasses wastewater treatment in this study. The maximum power density of 1410.2 mW/m(2) was obtained with a current density of 4947.9 mA/m(2) when the high strength molasses wastewater with chemical oxygen demand (COD) of 127,500 mg/l was employed as the influent. The total COD, sulfate and color removal efficiencies of the proposed system were achieved of 53.2%, 52.7% and 41.1%, respectively. Each unit of this system had respective function and performed well when integrated together. The UASB reactor unit was mainly responsible for COD removal and sulfate reduction, while the MFC unit was used for the oxidation of generated sulfide with electricity generation. The BAF unit dominated color removal and phenol derivatives degradation. This study is a beneficial attempt to combine MFC technology with conventional anaerobic-aerobic processes for actual wastewater treatment. PMID:19604688
Zhang, Baogang; Zhao, Huazhang; Zhou, Shungui; Shi, Chunhong; Wang, Chao; Ni, Jinren
Treatment of fish processing wastewater in a one- or two-step upflow anaerobic sludge blanket (UASB) reactor.
The performance of one-step UASB reactors treating fish processing wastewater of different lipid levels was determined using artificially generated influent simulating that of the canning of sardines and tuna. The organic loading rates (OLR) and the hydraulic retention times (HRT) were 5-8 g COD.l(-1).d(-1) and 11-12 hours, respectively. In treating a wastewater that contains 3-4 g.l(-1) total COD of which 5-9% was lipids, the COD removal and conversion to methane were ca.78% and 61%, respectively. In treating a wastewater with a higher lipid content (ca. 47% of the total COD), the total COD removed and converted to methane were 92% and 47%, respectively. A considerable part of the influent total COD was removed via adsorption on reactor surfaces and sludge particles. The adsorption of lipids on sludge particles threatens the stability of the UASB operation. Thus, the performance of a first-step UASB reactor in removing suspended solids (SS) from a "high-lipid" wastewater was also determined in this study. PMID:12188546
Palenzuela-Rollon, A; Zeeman, G; Lubberding, H J; Lettinga, G; Alaerts, G J
Role of calcium oxide in sludge granulation and methanogenesis for the treatment of palm oil mill effluent using UASB reactor.
The granulation process in palm oil mill effluent using calcium oxide-cement kiln dust (CaO-CKD) provides an attractive and cost effective treatment option. In this study the efficiency of CaO-CKD at doses of 1.5-20 g/l was tested in batch experiments and found that 10 g of CaO/l caused the greatest degradation of VFA, butyrate and acetate. An upflow anaerobic sludge blanket (UASB) reactor was operated continuously at 35░C for 150 days to investigate the effect of CaO-CKD on sludge granulation and methanogenesis during start-up. The treatment of POME emphasized the influence of varying organic loading rates (OLR). Up to 94.9% of COD was removed when the reactor was fed with the 15.5-65.5 g-CODg/l at an OLR of 4.5-12.5 kg-COD/m(3)d, suggesting the feasibility of using CaO in an UASB process to treat POME. The ratio of volatile solids/total solids (VS/TS) and volatile fatty acids in the anaerobic sludge in the UASB reactor decreased significantly after long-term operation due to the precipitation of calcium carbonate in the granules. Granulation and methanogenesis decreased with an increase in the influent CaO-CKD concentration. PMID:22047724
Ahmad, Anwar; Ghufran, Rumana; Abd Wahid, Zularisam
Energy saving system with high effluent quality for municipal sewage treatment by UASB-DHS.
An up-flow anaerobic sludge blanket (UASB) - down-flow hanging sponge (DHS) was applied to Japanese municipal sewage treatment, and its treatability, energy consumption, and sludge production were evaluated. The designed sewage load was 50 m(3)/d. The sewage typically had a chemical oxygen demand (COD) of 402 mg/L, a suspended solids (SS) content of 167 mg/L, and a temperature of 17-29 ░C. The UASB and DHS exhibited theoretical hydraulic retention times of 9.7 and 2.5 h, respectively. The entire system was operated without temperature control. Operation was started with mesophilic anaerobic digested sludge for the UASB and various sponge media for the DHS. Continuous operational data suggest that although the cellulose decomposition and methanogenic process in the UASB are temperature sensitive, stable operation can be obtained by maintaining a satisfactory sludge volume index and sludge concentration. For the DHS, the cube-type medium G3-2 offers superior filling rates, biological preservation and operational execution. The SS derived from the DHS contaminated the effluent but could be removed by optional sand filtration. A comparison with conventional activated sludge (CAS) treatment confirmed that this system is adequate for municipal sewage treatment, with an estimated energy requirement and excess sludge production approximately 75 and 85% less than those of CAS, respectively. PMID:22828294
Tanaka, H; Takahashi, M; Yoneyama, Y; Syutsubo, K; Kato, K; Nagano, A; Yamaguchi, T; Harada, H
Enhancing the start-up of a UASB reactor treating domestic wastewater by adding a water extract of Moringa oleifera seeds
Water extract of Moringa oleifera seeds (WEMOS) was used to enhance the start-up of a self-inoculated upflow anaerobic sludge blanket (UASB) reactor treating raw domestic wastewater. Two reactors labelled control (RC) and WEMOS addition (RM) were started without special inoculum. Both reactors were fed continuously for 22 weeks with domestic wastewater containing an average total chemical oxygen demand (COD) of
Y. Kalogo; A. M'Bassiguiķ Sķka; W. Verstraete
Anaerobic treatment of raw domestic sewage at ambient temperatures using a granular bed UASB reactor
Results obtained in a 120 liter 2 m high UASB-reactor with raw domestic sewage and using a granular sugar beet waste cultivated seed sludge, reveal the feasibility of this type of anaerobic treatment for domestic sewage. Under dry weather conditions 65-85% COD reduction can be achieved at temperatues in the range of 8-20 degrees C and at hydraulic loads at high as 2 cu.m. m-3.day-1. In the case of heavy rainfall the COD-reduction drops to 50-70% and occasionally, viz. at very low influent COD, even below 50%. The net methane production amounts to 7.1-7.3 cu.m. PE-1.year-1, and the excess sludge production ranges from 5.0-8.6 kg TS.PE1.year-1. Regarding the results obtained anaerobic treatment of raw sewage not only looks an attractive proposition for tropic areas but also for moderate climatic areas. (Refs. 19).
Lettinga, G.; Roersma, R.; Grin, P.
Treatment of municipal wastewater UASB reactor effluent by unconventional flotation and UV disinfection.
Post-treatment of an UASB reactor effluent, fed with domestic sewage, was conducted using two-stage flotation and UV disinfection. Results were compared to those obtained in a parallel stabilisation pond. The first flotation stage employed 5 - 7.5 mg L(-1) cationic flocculant to separate off more than 99% of the suspended solids. Then, phosphate ions were completely recovered using carrier flotation with 5-25 mg L(-1) of Fe (FeCl3) at pH 6.3-7.0. This staged flotation led to high recoveries of water and allowed us to separate organic matter and phosphate bearing sludge. The water still contained about 1 x 10(2) NMP/100 mL total coliforms, which were removed using UV radiation to below detection levels. Final water turbidity was < 1.0 NTU, COD < 20 mg L(-1) O2 and 71 mNm(-1), the liquid/air interfacial tension. This flotation-UV flowsheet was found to be more efficient than the treatment in the stabilisation pond and appears to have some potential for water reuse. Results were discussed in terms of the biological, chemical and physicochemical mechanisms involved. PMID:16180444
Tessele, F; Monteggia, L O; Rubio, J
Sequential treatment of diluted olive pomace leachate by digestion in a pilot scale UASB reactor and BDD electrochemical oxidation.
The efficiency of the anaerobic treatment of olive pomace leachate (OPL) at mesophilic conditions was investigated. Daily and cumulative biogas production was measured during the operational period. The maximum biogas flowrate was 65ĀL/d, of which 50% was methane. In addition, the applicability of electrochemical oxidation as an advanced post-treatment method for the complete removal of chemical oxygen demand (COD) from the anaerobically treated OPL was evaluated. The diluted OPL, having a pH of 6.5 and a total COD of 5Āg/L, was first treated in a 600ĀL, pilot-scale up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated for 71 days at mesophilic conditions (32Ā▒Ā2Ā░C) in a temperature-controlled environment at a hydraulic retention time of 3 days, and organic loading rates (OLR) between 0.33 and 1.67Āg COD/(L.d). The UASB process led to a COD removal efficiency between 35 and 70%, while the particulate matter of the wastewater was effectively removed by entrapment in the sludge blanket of the reactor. When the anaerobic reactor effluent was post-treated over a boron-doped diamond (BDD) anode at 18 A and in the presence of 0.17% NaCl as the supporting electrolyte, complete removal of COD was attained after 7Āh of treatment predominantly through total oxidation reactions. During electrochemical experiments, three groups of organo-chlorinated compounds, namely trihalomethanes (THMs), haloacetonitriles (HANs) and haloketons (HKs), as well as 1,2-dichloroethane (DCA) and chloropicrin were identified as by-products of the process; these, along with the residual chlorine are thought to increase the matrix ecotoxicity to Artemia salina. PMID:24704905
Katsoni, Alphathanasia; Mantzavinos, Dionissios; Diamadopoulos, Evan
Quantification of organic and nitrogen removal in downflow hanging sponge (DHS) systems as a post-treatment of UASB effluent.
The aim of this research was to investigate the nature and composition of organic substrate in two down-flow hanging sponge (DHS) systems using mixed fungal (FDHS) and bacterial (BDHS) cultures treatment for UASB effluent of tapioca starch wastewater, evaluated by COD fractionations and two material balances. The random type DHS reactors were operated as modular columns consisting of four identical segments connected vertically. Results of the wastewater characterization showed that carbonaceous fractions were varied on a function of DHS height. Two balances applied to experimental data were for chemical oxygen demand (COD) and nitrogen (N). Results of mass balance calculations can also be used to examine the process behavior of two DHS systems to improve the organic and nitrogen removal mechanisms. PMID:21045340
Wichitsathian, B; Racho, P
Treatment of domestic sewage in a combined UASB/RBC system. Process optimization for irrigation purposes.
A Rotating Biological Contactor (RBC) was fed with raw domestic wastewater or anaerobic effluents. The experiments were conducted at increasing operational temperatures viz. 11, 20 and 30 degrees C to assess the potential increase in removal efficiencies for the different COD fractions (COD(total), COD(suspended), COD(colloidal) and COD(soluble)), E. coli and in the nitrification rate. The results clearly show that, the RBC at HRT of 2.5 h and OLR of 47 g COD/m2 x d provided a very high residual COD(total) value of 228 mg/l when treating domestic wastewater. This was not the case as compared to the results obtained for the system when operated at the same HRT but at lower OLR's of 27, 20 and 14.5 g COD/m2 x d with a UASB effluent at operational temperatures of 11, 20 and 30 degrees C respectively. The residual COD(total) values amounted to 100, 85 and 72 mg/l in the final effluents. Moreover, a high removal of ammonia and low residual values of E. coli was found for the RBC when treating a UASB effluent at operational temperature of 30 degrees C as compared to the situation for treatment of domestic wastewater and UASB effluent at lower temperatures of 11 and 20 degrees C. It can be concluded that an efficient pre-treatment of sewage implies a substantial reduction of OLR applied to the RBC and consequently improves the residual of COD(total) ammonia and E. coli in the final effluent. Therefore, this study supports using a combined system UASB/RBC for treatment of domestic wastewater for reuse in irrigation. PMID:12926629
Tawfik, A; Zeeman, G; Klapwijk, A; Sanders, W; El-Gohary, F; Lettinga, G
Recovery strategies for tackling the impact of phenolic compounds in a UASB reactor treating coal gasification wastewater.
The impact of phenolic compounds (around 3.2 g/L) resulted in a completely failed performance in a mesophilic UASB reactor treating coal gasification wastewater. The recovery strategies, including extension of HRT, dilution, oxygen-limited aeration, and addition of powdered activated carbon were evaluated in batch tests, in order to obtain the most appropriate way for the quick recovery of the failed reactor performance. Results indicated that addition of powdered activated carbon and oxygen-limited aeration were the best recovery strategies in the batch tests. In the UASB reactor, addition of powdered activated carbon of 1 g/L shortened the recovery time from 25 to 9 days and oxygen-limited aeration of 0-0.5 mgO2/L reduced the recovery time to 17 days. Reduction of bioavailable concentration of phenolic compounds and recovery of sludge activity were the decisive factors for the recovery strategies to tackle the impact of phenolic compounds in anaerobic treatment of coal gasification wastewater. PMID:22033369
Wang, Wei; Han, Hongjun
Toxicity and treatability of leachate: application of UASB reactor for leachate treatment from Okhla landfill, New Delhi.
This study reports applicability of upflow anaerobic sludge blanket (UASB) process to treat the leachate from a municipal landfill located in Delhi. A laboratory scale reactor was operated at an organic loading rate of 3.00 kg chemical oxygen demand (COD)/m(3) d corresponding to a hydraulic retention time (HRT) of 12 h for over 8 months. The effect of toxicity of leachate, and feed composition on the treatability of leachate was evaluated. Average COD of the leachate, during the study period varied between 8,880 and 66,420 mg/l. Toxicity of the leachate used during a period of 8 months varied from LC50 1.22 to 12.35 for 96 h. The removal efficiency of soluble COD ranged between 91 and 67% for fresh leachate and decreased drastically from 90 to 35% for old leachate having high toxicity. The efficiency varied from 81 to 65%. The reactor performed more efficiently for the treatment of fresh leachate (less toxic, LC50 11.64, 12.35, and 12.15 for 96 h) as compared with old leachate (more toxic, LC50 1.22 for 96 h). Toxicity of the leachate affected its treatment potential by the UASB. PMID:22546807
Singh, V; Mittal, A K
Application of an innovative methodology to improve the starting-up of UASB reactors treating domestic sewage.
This study shows the results obtained during the starting-up evaluation of an UASB reactor treating domestic sewage. It is located in the municipality of Ginebra, Valle del Cauca region in Colombia. Its design flow is 7.5 l/s with a maximum capacity of 10 l/s. The reactor was seeded with a deficient quality inoculum which accounted for 20% of the total reactor volume. The starting-up methodology comprised the sequential washing of the sludge (inoculum) by applying three different upflow velocities. This procedure resembles what other authors term the "selective pressure method". Once the sludge was washed, the reactor was started-up with an initial hydraulic retention time (HRT) of 24.9 hours, which was steadily reduced down to 6.7 hours in the final stage. Along the starting-up phase, there was a positive evolution in terms of quantity, quality and spatial distribution of the sludge. Consequently, there was a positive evolution in organic matter removal mechanisms. For HRT above 14 hours, the removal mechanisms were mainly physical whilst for HRT below 9 hours the removal mechanisms were mostly biological. Based on the above considerations and on the water quality parameters measured, it may be concluded that the start-up of an UASB reactor for domestic sewage treatment seeded with a low quality inoculum can be done with HRT as low as 15 or 12 hours. In this way, it is possible to reduce the starting-up period of these reactors down to 4 to 6 weeks, provided that the starting-up methodology is properly applied. PMID:11575096
RodrĒguez, J A; Pe±a, M R; Manzi, V
Biotic and abiotic processes contribute to successful anaerobic degradation of cyanide by UASB reactor biomass treating brewery waste water.
In contrast to the general aerobic detoxification of industrial effluents containing cyanide, anaerobic cyanide degradation is not well understood, including the microbial communities involved. To address this knowledge gap, this study measured anaerobic cyanide degradation and the rearrangements in bacterial and archaeal microbial communities in an upflow anaerobic sludge blanket (UASB) reactor biomass treating brewery waste water using bio-methane potential assays, molecular profiling, sequencing and microarray approaches. Successful biogas formation and cyanide removal without inhibition were observed at cyanide concentrations up to 5 mg l(-1). At 8.5 mg l(-1) cyanide, there was a 22 day lag phase in microbial activity, but subsequent methane production rates were equivalent to when 5 mg l(-1) was used. The higher cumulative methane production in cyanide-amended samples indicated that part of the biogas was derived from cyanide degradation. Anaerobic degradation of cyanide using autoclaved UASB biomass proceeded at a rate more than two times lower than when UASB biomass was not autoclaved, indicating that anaerobic cyanide degradation was in fact a combination of simultaneous abiotic and biotic processes. Phylogenetic analyses of bacterial and archaeal 16S rRNA genes for the first time identified and linked the bacterial phylum Firmicutes and the archaeal genus Methanosarcina sp. as important microbial groups involved in cyanide degradation. Methanogenic activity of unadapted granulated biomass was detected at higher cyanide concentrations than reported previously for the unadapted suspended biomass, making the aggregated structure and predominantly hydrogenotrophic nature of methanogenic community important features in cyanide degradation. The combination of brewery waste water and cyanide substrate was thus shown to be of high interest for industrial level anaerobic cyanide degradation. PMID:23726700
Novak, Domen; Franke-Whittle, Ingrid H; Pirc, Elizabeta Tratar; Jerman, Vesna; Insam, Heribert; Logar, Romana MarinÜek; Stres, Bla×
The settling characteristics and mean settling velocity of granular sludge in upflow anaerobic sludge blanket (UASB)-like reactors.
Mean settling velocity of granular sludge in full-scale UASB (upflow anaerobic sludge blanket) and EGSB (expanded granular sludge bed) reactors was evaluated by settling column tests, and a settling velocity model based on the experimental results and available literature data was developed. It is concluded that the settling velocity should be calculated by the Allen formula, because the settling process of the granules is in the category of intermediate flow regime rather than in the laminar flow one. The comparison between calculated and measured values of the settling velocity shows an excellent agreement, with an average relative error of 4.04%. A simple but reliable mathematical method to determine the settling velocity is therefore proposed. PMID:16944002
Liu, Yong-Hong; He, Yan-Ling; Yang, Shu-Cheng; Li, Yao-Zhong
Effect of temperature on low-strength wastewater treatment by UASB reactor using poly(vinyl alcohol)-gel carrier.
The feasibility of treating low-strength wastewater with an up-flow anaerobic sludge blanket (UASB) reactor, using a poly(vinyl alcohol)-gel carrier, at various temperatures and hydraulic retention times (HRTs) was examined. The temperature was decreased from 35░C to 25░C and then to 15░C. The HRT was reduced from 2.0 h to 0.22 h. The COD removal rate reached 28 kg-COD m(-3)d(-1) at 35░C, 16 kg-COD m(-3)d(-1) at 25░C, and 6 kg-COD m(-3)d(-1) at 15░C. The COD removal rate was reduced by half for each temperature reduction of 10░C. PMID:22014700
Khanh, Dophuong; Quan, Laiminh; Zhang, Wenjie; Hira, Daisuke; Furukawa, Kenji
Diversity and dynamics of ammonia-oxidizing bacterial communities in a sponge-based trickling filter treating effluent from a UASB reactor.
Changes in ammonia-oxidizing bacterial (AOB) population dynamics were examined in a new sponge-based trickling filter (TF) post-upflow anaerobic sludge blanket (UASB) reactor by denaturating gradient gel electrophoresis (DGGE), and these changes were linked to relevant components influencing nitrification (chemical oxygen demand (COD), nitrogen (N)). The sponge-based packing media caused strong concentration gradients along the TF, providing an ecological selection of AOB within the system. The organic loading rate (OLR) affected the population dynamics, and under higher OLR or low ammonium-nitrogen (NH4(+)-N) concentrations some AOB bands disappeared, but maintaining the overall community function for NH4(+)-N removal. The dominant bands present in the upper portions of the TF were closely related to Nitrosomonas europaea and distantly affiliated to Nitrosomonas eutropha, and thus were adapted to higher NH4(+)-N and organic matter concentrations. In the lower portions of the TF, the dominant bands were related to Nitrosomonas oligotropha, commonly found in environments with low levels of NH4(+)-N. From a technology point of view, changes in AOB structure at OLR around 0.40-0.60 kgCOD m(-3) d(-1) did not affect TF performance for NH4(+)-N removal, but AOB diversity may have been correlated with the noticeable stability of the sponge-based TF for NH4(+)-N removal at low OLR. This study is relevant because molecular biology was used to observe important features of a bioreactor, considering realistic operational conditions applied to UASB/sponge-based TF systems. PMID:23925194
Mac Conell, E F A; Almeida, P G S; Zerbini, A M; Brandt, E M F; Ara·jo, J C; Chernicharo, C A L
[Analysis of hydrogen-production performance in a UASB system at low pH].
This experiment used upflow anaerobic sludge blanket (UASB) with brown sugar water as fermentation substrate and sewage sludge as the initiation sludge of the reaction, which was made into granular sludge by adding activated carbon. Emphasis was placed on assessing the hydrogen production performance of the UASB hydrogen bio-production system in the stable ethanol-type fermentation. Under the conditions that the influent COD was 4000 mg x L(-1), the temperature was (35 +/- 1) degrees C and the hydraulic retention time (HRT) was 8 h, a certain amount of NaHCO3 was added to adjust pH from 3.72 to 3.80, 3.85, 3.94 and 4.04, the hydrogen production rate increased correspondingly from the initial 5.5 L x d(-1) to about 7.0, 8.0, 9.5 and 6.0 L x d(-1), which was improved by 27.27%, 45.45%, 72.73% and 9.09%, respectively. The highest hydrogen production rate and gas yield were observed at pH 3.94. The maximal gas yield was 15.83 L x d(-1), which was 1.75 times as high as the initial production. Meanwhile, the hydrogen production efficiency was 58.05%. This study broke through the lower limit pH value 4.0 in fermentative hydrogen production. PMID:24455947
Zhao, Jian-Hui; Zhang, Bai-Hui; Li, Ning; Wang, Bing; Li, Yong-Feng
Anaerobic treatment of pre-hydrolysate liquor (PHL) from a rayon grade pulp mill: Pilot and full-scale experience with UASB reactors
Pilot studies were carried out for the treatment of pre-hydrolysate liquor (PHL), a high strength effluent (COD: 70,000¢80,000mg\\/l) emanating from a rayon grade pulp mill using up-flow anaerobic sludge blanket reactor (UASB). Substrate inhibition was avoided with optimum COD feed of around 25,000mg\\/l. This was achieved by diluting the PHL with a low strength effluent stream known as alkali back
A. Gangagni Rao; A. N. Bapat
Anaerobic degradation of azo dye Drimaren blue HFRL in UASB reactor in the presence of yeast extract a source of carbon and redox mediator
This paper presents results on anaerobic degradation of the azo dye blue HFRL in a bench scale Upflow anaerobic sludge blanket\\u000a (UASB) reactor operated at ambient temperature. The results show that the addition of yeast extract (500Āmg\\/L) increased color\\u000a removal (PĀ<Ā0.05) from 62 to 93% despite the low chemical oxygen demand (COD) removal (~35%) which happened due to volatile fatty
B. E. L. BaĻta; S. F. Aquino; S. Q. Silva; C. A. Rabelo
Investigation and optimization of the novel UASB-MFC integrated system for sulfate removal and bioelectricity generation using the response surface methodology (RSM).
COD/sulfate ratio and hydraulic residence time (HRT), both of which influence sulfate loadings jointly, are recognized as the most two important affecting factors for sulfate removal and bioelectricity generation in the novel up-flow anaerobic sludge blanket reactor-microbial fuel cell (UASB-MFC) integrated system. The response surface methodology (RSM) was employed for the optimization of this system and the optimum condition with COD/sulfate ratio of 2.3 and HRT of 54.3h was obtained with the target of maximizing the power output. In terms of maximizing the total sulfate removal efficiency, the obtained optimum condition was COD/sulfate ratio of 3.7 and HRT of 55.6h. Experimental results indicated the undistorted simulation and reliable optimized results. These demonstrated that RSM was effective to evaluate and optimize the UASB-MFC system for sulfate removal and energy recovery, providing a promising guide to further improvement of the system for potential applications. PMID:22985846
Zhang, Baogang; Zhang, Jing; Yang, Qi; Feng, Chuanping; Zhu, Yuling; Ye, Zhengfang; Ni, Jinren
Effects of alkalinity and co-substrate on the performance of an upflow anaerobic sludge blanket (UASB) reactor through decolorization of Congo Red azo dye.
The effect of substrate (glucose) concentrations and alkalinitiy (NaHCO3) on the decolorization of a synthetic wastewater containing Congo Red (CR) azo dye was performed in an upflow anaerobic sludge blanket (UASB). Color removal efficiencies approaching 100% were obtained at glucose-COD concentrations varying between 0 and 3000 mg/l. The methane production rate and total aromatic amine (TAA) removal efficiencies were found to be 120 ml per day and 43%, respectively, while the color was completely removed during glucose-COD free operation of the UASB reactor. The complete decolorization of CR dye under co-substrate free operation could be attributed to TAA metabolism which may provide the electrons required for the cleavage of azo bond in CR dye exist in the UASB reactor. No significant differences in pH levels (6.6-7.4), methane production rates (2000-2700 ml/day) and COD removal efficiencies (82-90%) were obtained for NAHCO3 concentrations ranging between 550 and 3000 mg/l. However, decolorization efficiency remained at 100% with decreasing NaHCO3 concentrations as low as 250 mg/l in the feed. An alkalinity/COD ratio of 0.163 in the feed was suggested for simultaneous optimum COD and color removal. PMID:15501672
I?ik, Mustafa; Sponza, Delia Teresa
Optimization of petroleum refinery effluent treatment in a UASB reactor using response surface methodology.
An upflow anaerobic sludge blanket (UASB) bioreactor was successfully used for the treatment of petroleum refinery effluent. Before optimization, chemical oxygen demand (COD) removal was 81% at a constant organic loading rate (OLR) of 0.4 kg/m(3) d and a hydraulic retention time (HRT) of 48 h. The rate of biogas production was 559 mL/h at an HRT of 40 h and an influent COD of 1000 mg/L. Response surface methodology (RSM) was applied to predict the behaviors of influent COD, upflow velocity (V(up)) and HRT in the bioreactor. RSM showed that the best models for COD removal and biogas production rate were the reduced quadratic and cubic models, respectively. The optimum region, identified based on two critical responses, was an influent COD of 630 mg/L, a V(up) of 0.27 m/h, and an HRT of 21.4 h. This resulted in a 76.3% COD removal efficiency and a 0.25 L biogas/L feed d biogas production rate. PMID:21983166
Rastegar, S O; Mousavi, S M; Shojaosadati, S A; Sheibani, S
Effect of loading rate variation on soybean protein wastewater treatment by UASB reactor
NASA Astrophysics Data System (ADS)
In order to improve the efficiency and evaluate the feasibility of anaerobic digestion for treatment of soybean protein wastewater. The stability and performance of the Up-Flow Anaerobic Sludge Blanket (UASB) process was investigated at different organic loading rates (OLRS) and hydraulic retention times over 200 days. When chemical oxygen demand (COD) reached maximum, the loading rate was adjusted in a small way and indicators such as VFA, pH and COD in effluent as well as gas production are observed. These experimental results clearly showed that, the most proper corresponding organic loading rate (OLR) and hydraulic retention time were 6 kg/ (m3.d) (COD = 6000 mg/L) and 24 h respectively. Up to 85% of COD was removed and the CH4 production rate of 3.2 m3/(m3.d) was obtained. The produced biogas contained 72% of CH4. In the mean time, anaerobic sludge multiplies more faster and exiguous particles appeared. Granules with diameter 1-3 mm.
Sun, Yi; Li, Yongfeng; Guo, Zi-Rui; Jiao, An-Ying; Han, Wei; Yang, Chuan-Ping
Comparison between polishing (maturation) ponds and subsurface flow constructed wetlands (planted and unplanted) for the post-treatment of the effluent from UASB reactors.
This paper presents the results of a comparison of the performance of two treatment systems operating in parallel, with the same influent wastewater. The investigated systems are (i) UASB + three polishing ponds in series + coarse filter (200 population equivalents) and (ii) UASB + subsurface flow constructed wetlands (50 population equivalents). Two wetland units, operating in parallel, were analysed, being one planted (Typha latifolia) and the other unplanted. The systems were located in Belo Horizonte, Brazil. The wetland systems showed to be more efficient in the removal of organic matter and suspended solids, leading to good effluent BOD and COD concentrations and excellent SS concentrations. The planted wetland performed better than the unplanted unit, but the latter was also able to provide a good effluent quality. The polishing pond system was more efficient in the removal of nitrogen (ammonia) and coliforms (E. coli). Land requirements and cost considerations are presented. PMID:20220242
von Sperling, M; Dornelas, F L; AssunńŃo, F A L; de Paoli, A C; Mabub, M O A
Optimization of linear alkylbenzene sulfonate (LAS) degradation in UASB reactors by varying bioavailability of LAS, hydraulic retention time and specific organic load rate.
Degradation of linear alkylbenzene sulfonate (LAS) in UASB reactors was optimized by varying the bioavailability of LAS based on the concentration of biomass in the system (1.3-16 g TS/L), the hydraulic retention time (HRT), which was operated at 6, 35 or 80 h, and the concentration of co-substrates as specific organic loading rates (SOLR) ranging from 0.03-0.18 g COD/g TVS.d. The highest degradation rate of LAS (76%) was related to the lowest SOLR (0.03 g COD/g TVS.d). Variation of the HRT between 6 and 80 h resulted in degradation rates of LAS ranging from 18% to 55%. Variation in the bioavailability of LAS resulted in discrete changes in the degradation rates (ranging from 37-53%). According to the DGGE profiles, the archaeal communities exhibited greater changes than the bacterial communities, especially in biomass samples that were obtained from the phase separator. The parameters that exhibited more influence on LAS degradation were the SOLR followed by the HRT. PMID:23196232
Okada, Dagoberto Y; Delforno, Tiago P; Esteves, Andressa S; Sakamoto, Isabel K; Duarte, Iolanda C S; Varesche, Maria B A
Sugarcane molasses-based bio-ethanol wastewater treatment by two-phase multi-staged up-flow anaerobic sludge blanket (UASB) combination with up-flow UASB and down-flow hanging sponge.
This study was designed to evaluate a treatment system for high strength wastewater (vinasse) from a sugarcane molasses-based bio-ethanol plant in Thailand. A laboratory-scale two-phase treatment system composed of a sulfate reducing (SR) tank and multi-staged up-flow anaerobic sludge blanket (MS-UASB) reactor was used as the pre-treatment unit. Conventional UASB and down-flow hanging sponge (DHS) reactors were used as the post-treatment unit. The treatment system was operated for 300 days under ambient temperature conditions (24.6-29.6 ░C). The hydraulic retention time (HRT) in each unit was kept at 25 h for the two-phase system and 23 h for the UASB&DHS. The influent concentration was allowed to reach up to 15,000 mg chemical oxygen demand (COD)/L. COD removal efficiency (based on influent COD) of the two-phase MS-UASB and the UASB&DHS was 54.9 and 18.7%, respectively. Due to the effective removal of sulfide in the SR tank, the MS-UASB achieved a high methane conversion ratio of up to 97%. In DHS, nitrification occurred at the outside portion of the sponge media while denitrification occurred at the inside. Consequently, 27% of the total nitrogen (TN) was removed. An amount of 32% of residual nitrogen (28 mgN/L) was in the form of nitrate, a better nitrogen state for fertilizer. PMID:24647181
Choeisai, P; Jitkam, N; Silapanoraset, K; Yubolsai, C; Yoochatchaval, W; Yamaguchi, T; Onodera, T; Syutsubo, K
Co-digestion to support low temperature anaerobic pretreatment of municipal sewage in a UASB-digester.
The aim of this work was to demonstrate that co-digestion improves soluble sewage COD removal efficiency in treatment of low temperature municipal sewage by a UASB-digester system. A pilot scale UASB-digester system was applied to treat real municipal sewage, and glucose was chosen as a model co-substrate. Co-substrate was added in the sludge digester to produce additional methanogenic biomass, which was continuously recycled to inoculate the UASB reactor. Soluble sewage COD removal efficiency increased from 6 to 23%, which was similar to its biological methane potential (BMP). Specific methanogenic activity of the UASB and of the digester sludge at 15░C tripled to a value respectively of 43 and 39 mg CH4-COD/(g VSS d). Methane production in the UASB reactor increased by more than 90% due to its doubled methanogenic capacity. Therefore, co-digestion is a suitable approach to support a UASB-digester for pretreatment of low temperature municipal sewage. PMID:24080295
Zhang, Lei; Hendrickx, Tim L G; Kampman, Christel; Temmink, Hardy; Zeeman, Grietje
Effect of temperature on anaerobic treatment of black water in UASB-septic tank systems.
The effect of northern European seasonal temperature changes and low temperature on the performance of upflow anaerobic sludge blanket (UASB)-septic tanks treating black water was studied. Three UASB-septic tanks were monitored with different operational parameters and at different temperatures. The results indicated the feasibility of the UASB-septic tank for (pre)treatment of black water at low temperatures with respect to removal of suspended solids and dissolved organic material. Inoculum sludge had little effect on COD(ss) removal, though in the start-up phase some poorly adapted inoculum disintegrated and washed out, thus requiring consideration when designing the process. Removal of COD(dis) was at first negative, but improved as the sludge adapted to low temperature. The UASB-septic tank alone did not comply with Finnish or Dutch treatment requirements and should therefore be considered mainly as a pre-treatment method. However, measuring the requirements as mgCOD l(-1) may not always be the best method, as the volume of the effluent discharged is also an important factor in the final amount of COD entering the receiving water bodies. PMID:16765592
Luostarinen, Sari; Sanders, Wendy; Kujawa-Roeleveld, Katarzyna; Zeeman, Grietje
Comparison of UASB and EGSB performance on the anaerobic biodegradation of 2,4-dichlorophenol.
The anaerobic degradation of 2,4-dichlorophenol (2,4-DCP) in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors using glucose as main carbon source was studied. The performance of both systems was compared in terms of 2,4-DCP and COD removal efficiencies, methane production, stability, granular sludge adaptability as well as reversion of the bacterial inhibition. Both organic and 2,4-DCP loading rates were incrementally varied through the experiments. With loading rates of 1.9 gCODL(-1)d(-1) and 100mg 2,4-DCP L(-1)d(-1), 75% and 84% removal efficiencies of this compound, accompanied by COD consumption efficiencies of 61% and 80% were achieved in the UASB and EGSB reactors, respectively. In these conditions, methane production reached 0.088 L CH(4)g(-1) COD in the EGSB reactor whereas in the UASB reactor was almost negligible. Decreasing the 2,4-DCP loading rate to 30 mgL(-1)d(-1) an improvement in the methane production was observed in both reactors (methanogenic activity of 0.148 and 0.192 L CH(4)g(-1) COD in UASB and EGSB reactors, respectively). Efficiency of dechlorination was improved in both reactors from around 30% to 80% by reducing to one-half the COD due to a decreasing of the 4-chlorophenol concentration accumulated in the effluents of both reactors. The dechlorination efficiency of the UASB reactor was dramatically inhibited at a 2,4-DCP feed concentration above around 210 mgL(-1) because of 2,4-DCP accumulation in the effluent. SEM studies revealed no significant morphological changes in the sludge granules. PMID:19577792
Puyol, D; Mohedano, A F; Sanz, J L; RodrĒguez, J J
Extracellular polymers in granular sludge from different upflow anaerobic sludge blanket (UASB) reactors
Thermal extraction was used to quantify extracellular polymers (ECP) in granules from anaerobic upflow reactors. The optimal time for extraction was determined as the time needed before the intracellular material gives a significant contribution to the extracted extracellular material due to cell lysis. ECP contents of 41 to 92 mg Ę g-1 volatile suspended solids of granules were found depending
J. E. E. Schmidt; B. K. Ahring
Extracellular polymers in granular sludge from different upflow anaerobic sludge blanket ( UASB ) reactors
Thermal extraction was used to quantify extracellular polymers (ECP) in granules from anaerobic upflow reactors. The optimal time for extraction was determined as the time needed before the intracellular material gives a significant contribution to the extracted extracellular material due to cell lysis. ECP contents of 41 to 92 mg?Ę?g -1 volatile suspended solids of granules were found depending on
J. E. Schmidt; B. K. Ahring
Kinetics of lactate, acetate and propionate in unadapted and lactate-adapted thermophilic, anaerobic sewage sludge: the influence of sludge adaptation for start-up of thermophilic UASB-reactors
A thermophilic anaerobic sludge digestor was adapted to lactate metabolism. The adapted sludge showed an improved capacity for lactate degradation when tested by a batch activity test, compared to the performance of unadapted sludge. Acetate was the major intermediate produced during the degradation. When adapted sludge was used as the inoculum for a lactate-fed, upflow anaerobic sludge blanket (UASB) reactor,
Anders Hay S°rensen; Margrethe Winther-Nielsen; Birgitte K. Ahring
Effect of starch addition on the biological conversion and microbial community in a methanol-fed UASB reactor during long-term continuous operation.
The effect of starch addition on the microbial composition and the biological conversion was investigated using two upflow anaerobic sludge bracket (UASB) reactors treating methanolic wastewater: one reactor was operated with starch addition, and another reactor was operated without starch addition. Approximately 300 days of operation were performed at 30 kg COD/m(3)/d, and then, the organic load of the reactors was gradually increased to 120 kg COD/m(3)/d. Successful operation was achieved at 30 kg COD/m(3)/d in both reactors; however, the methanol-fed reactor did not perform well at 120 kg COD/m(3)/d while the methanol-starch-fed reactor did. The granule analysis revealed the granule developed further only in the methanol-starch-fed reactor. The results of the microbial community analysis revealed more Methanosaeta cells were present in the methanol-starch-fed reactor, suggesting the degradation of starch produced acetate as an intermediate, which stimulated the growth of Methanosaeta cells responsible for the extension of granules. PMID:21700450
Kobayashi, Takuro; Yan, Feng; Takahashi, Shintaro; Li, Yu-You
Biogas production from potato-juice, a by-product from potato-starch processing, in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors.
In this study, the utilization of potato-juice, the organic by-product from potato-starch processing, for biogas production was investigated in batch assay and in high rate anaerobic reactors. The maximum methane potential of the potato-juice determined by batch assay was 470 mL-CH(4)/gVS-added. Anaerobic digestion of potato-juice in an EGSB reactor could obtain a methane yield of 380 mL-CH(4)/gVS-added at the organic loading rate of 3.2 gCOD/(L-reactor.d). In a UASB reactor, higher organic loading rate of 5.1 gCOD/(L-reactor.d) could be tolerated, however, it resulted in a lower methane yield of 240 mL-CH(4)/gVS-added. The treatment of reactor effluent was also investigated. By acidification with sulfuric acid to pH lower than 5, almost 100% of the ammonia content in the effluent could be retained during the successive up-concentration process step. The reactor effluent could be up-concentrated by evaporation to minimize its volume, and later be utilized as fertilizer. PMID:21450459
Fang, Cheng; Boe, Kanokwan; Angelidaki, Irini
A review: The anaerobic treatment of sewage in UASB and EGSB reactors
The anaerobic treatment process is increasingly recognized as the core method of an advanced technology for environmental protection and resource preservation and it represents, combined with other proper methods, a sustainable and appropriate wastewater treatment system for developing countries. Anaerobic treatment of sewage is increasingly attracting the attention of sanitary engineers and decision makers. It is being used successfully in
Lucas Seghezzo; Grietje Zeeman; Jules B. van Lier; H. V. M. Hamelers; Gatze Lettinga
Assessment of electrochemical and chemical coagulation as post-treatment for the effluents of a UASB reactor treating cellulose pulp mill wastewater.
This paper presents results from exploratory experiments to test the technical feasibility of electrolytic treatment and coagulation followed by flocculation and sedimentation as post-treatment for the effluent of an UASB reactor treating simulated wastewater from an unbleached Kraft pulp mill. The electrolytic treatment provided up to 67% removal of the remaining COD and 98% of color removal. To achieve these efficiencies the energy consumption ranged from 14 Wh x l(-1) to 20 Wh x l(-1). The coagulation-flocculation treatment followed by settling required 350-400 mg x l(-1) of aluminium sulfate. The addition of a high molecular weight cationic polymer enhanced both COD and color removal. Both post-treatment processes are technically feasible. PMID:16180426
Buzzini, A P; Motheo, A J; Pires, E C
Treatment of coal gasification wastewater by a two-continuous UASB system with step-feed for COD and phenols removal.
A two-continuous mesophilic (37 ▒ 2░C) UASB system with step-feed was investigated as an attractive optimization strategy for enhancing COD and total phenols removal of the system and improving aerobic biodegradability of real coal gasification wastewater. Through the step-feed period, the maximum removal efficiencies of COD and total phenols reached 55-60% and 58-63% respectively in the system, at an influent flow distribution ratio of 0.2 and influent COD concentration of 2500 mg/L; the corresponding efficiencies were at low levels of 45-50% and 43-50% respectively at total HRT of 48 h during the single-feed period. The maximum specific methanogenic activity and substrate utilization rate were 592 ▒ 16 mg COD-CH(4)/(g VSS d) and 89 ▒ 12 mg phenol/(g VSS d) during the step-feed operation. After the anaerobic digestion with step-feed, the aerobic effluent COD concentration decreased from 270 ▒ 9 to 215 ▒ 10 mg/L. The results suggested that step-feed enhanced the degradation of refractory organics in the second reactor. PMID:21093254
Wang, Wei; Han, Hongjun; Yuan, Min; Li, Huiqiang; Fang, Fang; Wang, Ke
Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.
The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ▒ 0.6 ░C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ▒ 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 ▒ 54 to 431 ▒ 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater. PMID:23508162
Esparza-Soto, M; Arzate-Archundia, O; SolĒs-Morelos, C; Fall, C
Anaerobic treatment of pre-hydrolysate liquor (PHL) from a rayon grade pulp mill: pilot and full-scale experience with UASB reactors.
Pilot studies were carried out for the treatment of pre-hydrolysate liquor (PHL), a high strength effluent (COD: 70,000-80,000 mg/l) emanating from a rayon grade pulp mill using up-flow anaerobic sludge blanket reactor (UASB). Substrate inhibition was avoided with optimum COD feed of around 25,000 mg/l. This was achieved by diluting the PHL with a low strength effluent stream known as alkali back wash (ABW) available in the plant and also by partially recycling the reactor liquid outlet. An optimum organic loading rate (OLR) of 10 could be achieved with a COD reduction of 70-75%, a BOD reduction of 85-90% and a methane yield of 0.31-0.33 m3/kg of COD reduced. The pilot scale studies also revealed that addition of milk of lime (MOL) was essential for neutralization and buffering and DAP and urea to supplement the nutrients in the PHL. Based on the pilot studies, a full-scale high rate biomethanation plant was designed and erected for treating the PHL, which after some modification showed similar performance for COD, BOD reduction and methane yield. PMID:16330206
Rao, A Gangagni; Bapat, A N
Preliminary evaluation of the electrochemical and chemical coagulation processes in the post-treatment of effluent from an upflow anaerobic sludge blanket (UASB) reactor.
The main objective of this paper was to perform a preliminary comparative study between chemical and electrochemical coagulation processes, both followed by flocculation and sedimentation of an effluent from an upflow anaerobic sludge blanket (UASB) reactor treating simulated wastewater from an unbleached Kraft pulp mill. The electrochemical treatment removed up to 67% (with aluminum electrodes) and 82% (with stainless-steel electrodes) of the remaining chemical oxygen demand (COD) and 84% (stainless steel) and 98% (aluminum) of the color in the wastewater. These efficiencies were achieved with an energy consumption ranging from 14 to 20 Wh l(-1). The coagulation-flocculation treatment with ferric chloride and aluminum sulfate removed up to 87% and 90% of COD and 94% and 98% of color, respectively. The addition of a high molecular weight cationic polymer enhanced both COD and color removal efficiencies. The two post-treatment processes proved to be technically feasible; however the economical feasibility could not be assessed since the experiments were performed with small reactors that could distort scale factors. PMID:17134820
Buzzini, A P; Patrizzi, L J; Motheo, A J; Pires, E C
Comparison of UASB and EGSB performance on the anaerobic biodegradation of 2,4-dichlorophenol
The anaerobic degradation of 2,4-dichlorophenol (2,4-DCP) in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors using glucose as main carbon source was studied. The performance of both systems was compared in terms of 2,4-DCP and COD removal efficiencies, methane production, stability, granular sludge adaptability as well as reversion of the bacterial inhibition. Both organic and 2,4-DCP
D. Puyol; A. F. Mohedano; J. L. Sanz; J. J. RodrĒguez
Formation and impact of granules in fostering clean energy production and wastewater treatment in upflow anaerobic sludge blanket (UASB) reactors
Anaerobic reactors have acquired a new relevance in recent years due to their ability to generate methane from biodegradable wastewatersŌĆöthereby producing clean energy. Methane capture in this manner also prevents the escape of the greenhouse gas to the atmosphere which otherwise occurs when anaerobic conditions develop in drains and outfalls carrying wastewater. Of all the different types of anaerobic reactors
Tasneem Abbasi; S. A. Abbasi
Start-up of an anaerobic hybrid (UASB/filter) reactor treating wastewater from a coffee processing plant.
The ability of an anaerobic hybrid reactor, treating coffee wastewater, to achieve a quick start-up was tested at pilot scale. The unacclimatized seed sludge used showed a low specific methanogenic activity of 26.47 g CH4 as chemical oxygen demand (COD)/kg volatile suspended solids (VSS) x day. This strongly limited the reactor performance. After a few days of operation, a COD removal of 77.2% was obtained at an organic loading rate (OLR) of 1.89 kg COD/m3 x day and a hydraulic retention time (HRT) of 22 h. However, suddenly increasing OLR above 2.4 kg COD/m3 x day resulted in a deterioration in treatment efficiency. The reactor recovered from shock loads after shutdowns of 1 week. The hybrid design of the anaerobic reactor prevented the biomass from washing-out but gas clogging in the packing material was also observed. Wide variations in wastewater strength and flow rates prevented stable reactor operation in the short period of the study. PMID:16887646
Bello-Mendoza, R; Castillo-Rivera, M F
Removal of anaerobic soluble microbial products in a biological activated carbon reactor.
The soluble microbial products (SMP) in the biological treatment effluent are generally of great amount and are poorly biodegradable. Focusing on the biodegradation of anaerobic SMP, the biological activated carbon (BAC) was introduced into the anaerobic system. The experiments were conducted in two identical lab-scale up-flow anaerobic sludge blanket (UASB) reactors. The high strength organics were degraded in the first UASB reactor (UASB1) and the second UASB (UASB2, i.e., BAC) functioned as a polishing step to remove SMP produced in UASB1. The results showed that 90% of the SMP could be removed before granular activated carbon was saturated. After the saturation, the SMP removal decreased to 60% on the average. Analysis of granular activated carbon adsorption revealed that the main role of SMP removal in BAC reactor was biodegradation. A strain of SMP-degrading bacteria, which was found highly similar to Klebsiella sp., was isolated, enriched and inoculated back to the BAC reactor. When the influent chemical oxygen demand (COD) was 10,000 mg/L and the organic loading rate achieved 10 kg COD/(m3 x day), the effluent from the BAC reactor could meet the discharge standard without further treatment. Anaerobic BAC reactor inoculated with the isolated Klebsiella was proved to be an effective, cheap and easy technical treatment approach for the removal of SMP in the treatment of easily-degradable wastewater with COD lower than 10,000 mg/L. PMID:24520716
Dong, Xiaojing; Zhou, Weili; He, Shengbing
Performance of staged and non-staged up-flow anaerobic sludge bed (USSB and UASB) reactors treating low strength complex wastewater
The use of anaerobic processes to treat low-strength wastewater has been increasing in recent years due to their favourable\\u000a performance-costs balance. For optimal results, it is necessary to identify reactor configurations that are best suited for\\u000a this kind of application. This paper reports on the comparative study carried out with two high-rate anaerobic reactor systems\\u000a with the objective of evaluating
Susana Sevilla-Espinosa; Maricela Sol¾rzano-Campo; Ricardo Bello-Mendoza
Granulation in Upflow Anaerobic Sludge Blanket Reactor,
National Technical Information Service (NTIS)
The experiment was designed to study Upflow Anaerobic Sludge Blanket (UASB) reactor and to evaluate a methane fermentation process for the treatment of wastewater. The essential feature of the UASB process is high activity of anaerobic bacterial mass in t...
T. Hoaki T. Tomozawa S. Kaneko
Anaerobic dechlorination of pentachlorophenol in fixed-film and upflow anaerobic sludge blanket reactors using different inocula
Longterm performance and stability of two upflow anaerobic sludge blanket (UASB) reactors inoculated with granular sludge and treating a synthetic waste water containing pentachlorophenol (PCP) and phenol were studied. A similar system consisting of two fixed-film reactors inoculated with anaerobic digested sewage sludge were further studied. One reactor in each series received glucose in addition to the phenols. Dechlorination of
Hanne V. Hendriksen; Birgitte K. Ahring
UASB Treatment of Methanolic Pulp Wastewater with Addition of Waste Starch and Incinerated Ash
The pulp wastewater consists mainly of methanol. It is expected to treat using upflow anaerobic sludge blanket (UASB) process. Paper manufactories also produce waste starch and incinerated ash. The integrated treating for these wastes is desirable. In this study, two UASB reactors were operated to treat pulp wastewater with addition of waste starch and with addition of incinerated ash, receptively. Continuous operations of a UASB reactor treating pulp wastewater with addition of waste starch (PS reactor) and a UASB reactor treating pulp wastewater with addition of incinerated ash (PA reactor) , were investigated at mesophilic conditions. The PS reactor performed well with an average 93.7% total CODCr and 97.3% soluble CODCr removal efficiency in average at a maximum volumetric loading rate (VLR) of 16.0 kgCOD/m3/d. The PA reactor was also successfully operated with an average 95.3% total CODCr and 97.5% soluble CODCr removal efficiency in average at a maximum VLR of 14.6 kgCOD/m3/d. Successfully developed granules were obtained after over 140 days of operation in both reactors, and the granules were 1 to 2 mm in mean diameter. Microbial analysis revealed the genus Methanomethylovorans was predominant in the granules of both reactors.
Takahashi, Shintaro; Kobaysashi, Takuro; Li, Yu-You; Harada, Hideki
Application of molecular techniques to evaluate the methanogenic archaea and anaerobic bacteria in the presence of oxygen with different COD:sulfate ratios in a UASB reactor.
In this paper, the microbial characteristics of the granular sludge in the presence of oxygen (3.0+/-0.7 mg O2 l(-1)) were analyzed using molecular biology techniques. The granules were provided by an upflow anaerobic sludge blanket (UASB) operated over 469 days and fed with synthetic substrate. Ethanol and sulfate were added to obtain different COD/SO4(2-) ratios (3.0, 2.0, and 1.6). The results of fluorescent in situ hybridization (FISH) analyses showed that archaeal cells, detected by the ARC915 probe, accounted for 77%, 84%, and 75% in the COD/SO(4)(2-) ratios (3.0, 2.0, and 1.6, respectively). Methanosaeta sp. was the predominant acetoclastic archaea observed by optical microscopy and FISH analyses, and confirmed by sequencing of the excised bands of the DGGE gel with a similarity of 96%. The sulfate-reducing bacterium Desulfovibrio vulgaris subsp. vulgaris (similarity of 99%) was verified by sequencing of the DGGE band. Others identified microorganism were similar to Shewanella sp. and Desulfitobacterium hafniense, with similarities of 95% and 99%, respectively. These results confirmed that the presence of oxygen did not severely affect the metabolism of microorganisms that are commonly considered strictly anaerobic. We obtained mean efficiencies of organic matter conversion and sulfate reducing higher than 74%. PMID:18634895
Hirasawa, Julia Sumiko; Sarti, Arnaldo; Del Aguila, Nora Katia Saavedra; Varesche, Maria Bernadete A
Enhancement of a UASB-septic tank performance for decentralised treatment of strong domestic sewage.
The possibility of enhancing the process performance of the UASB-septic tank for treating strong sewage in Palestine by means of inoculating the reactor with well adapted anaerobic sludge and/or adding a packing media to the upper part of the reactor, creating an anaerobic hybrid (AH)-septic tank, was investigated. To achieve these objectives, two community onsite UASB-septic tank and AH-septic tank were operated in parallel at 2 days HRT for around 8 months overlapping the cold and hot periods of the year in Palestine. The achieved removal efficiencies of CODtot in the UASB-septic tank and AH-septic tank during the first months of operation, coinciding with the cold period and the subsequent hot period, were respectively 50 (+/- 15)% and 48 (+/- 15)% and 66 (+/- 8)% and 55 (+/- 8)%. This shows that the UASB-septic tank performed significantly better (p < 0.05) than the AH-septic tank after rather long periods of operation. The difference in the CODtot removal efficiency was mainly due to the better CODss removal efficiencies in the UASB-septic tank. The removal efficiencies over the last 50 days of operation for CODtot, CODsus, CODcol and CODdis were 70, 72, 77 and 55% and 53, 54, 78 and 45% for the UASB-septic tank and AH-septic tank, respectively. Comparing the here achieved COD removal efficiencies with previously reported efficiencies of UASB-septic tanks operated in Palestine shows that the reactor performance in terms of COD removal and conversion, during the first 8 months of operation, has improved substantially by being started with well adapted anaerobic sludge, simulating and predicting long-term performance. Adding packing media did not lead to an improvement. PMID:22097081
Mahmoud, Nidal; van Lier, Jules B
Improved vortex reactor system
An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.
Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)
Community onsite treatment of cold strong sewage in a UASB-septic tank.
Two community onsite UASB-septic tanks namely R1 and R2 were operated under two different HRT (2 days for R1 and 4 days for R2) in parallel over a year and monitored over the cold half of the year. During the monitoring period, the sewage was characterised by a high COD(tot) of 905mg/l with a high fraction of COD(ss), viz. about 43.7%, and rather low temperature of 17.3 degrees C. The achieved removal efficiencies in R1 and R2 for COD(tot), COD(sus), COD(col), COD(dis), BOD(5) and TSS were "51%, 83%, 20%, 24%, 45% and 74%" and "54%, 87%, 10%, 28%, 49% and 78%", respectively. The difference in the removal efficiencies of those parameters in R1 and R2 is marginal and was only significant (p<0.05) for COD(sus). The sludge filling period of the reactors is expected to be 4-7 years. In view of that, the UASB-septic tank system is a robust and compact system as it can be adequately designed in Palestine at 2 days HRT. PMID:18778934
Al-Jamal, Wafa; Mahmoud, Nidal
A nuclear reactor safety system is designed to provide an automatic ; safeguard for the reactor under fault conditions. It is also important that the ; safety system does not generate faults of its own. The basic layout of a safety ; system is described, and it is shown that application of the principles of ; coincidence and redundancy to
Reactor water cleanup system
A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling.
Gluntz, Douglas M. (San Jose, CA); Taft, William E. (Los Gatos, CA)
A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling. 1 figure.
Gluntz, D.M.; Taft, W.E.
Reactor Operations Monitoring System
The Reactor Operations Monitoring System (ROMS) is a VME based, parallel processor data acquisition and safety action system designed by the Equipment Engineering Section and Reactor Engineering Department of the Savannah River Site. The ROMS will be analyzing over 8 million signal samples per minute. Sixty-eight microprocessors are used in the ROMS in order to achieve a real-time data analysis.
An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.
Diebold, J.P.; Scahill, J.W.
Modelling anaerobic biofilm reactors--a review.
Anaerobic treatment has become a technically as well as economically feasible option for treatment of liquid effluents after the development of reactors such as the upflow anaerobic sludge blanket (UASB) reactor, expanded granular sludge bed (EGSB) reactor, anaerobic biofilter and anaerobic fluidized bed reactor (AFBR). Considerable effort has gone into developing mathematical models for these reactors in order to optimize their design, design the process control systems used in their operation and enhance their operational efficiency. This article presents a critical review of the different mathematical models available for these reactors. The unified anaerobic digestion model (ADM1) and its application to anaerobic biofilm reactors are also outlined. PMID:16517049
Saravanan, V; Sreekrishnan, T R
Biogas production from potato-juice, a by-product from potato-starch processing, in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors
In this study, the utilization of potato-juice, the organic by-product from potato-starch processing, for biogas production was investigated in batch assay and in high rate anaerobic reactors. The maximum methane potential of the potato-juice determined by batch assay was 470mL-CH4\\/gVS-added. Anaerobic digestion of potato-juice in an EGSB reactor could obtain a methane yield of 380mL-CH4\\/gVS-added at the organic loading rate
Cheng Fang; Kanokwan Boe; Irini Angelidaki
The inhibitory effects and removal of dieldrin in continuous upflow anaerobic sludge blanket reactors
The inhibitory effects and removal efficiency of dieldrin (DLD) in anaerobic reactors were investigated. Anaerobic toxicity assay (ATA) experiments conducted in batch reactors revealed that 30 mg\\/l DLD had inhibitory effects on the unacclimated mixed anaerobic cultures. Continuous reactor experiments performed in a lab-scale two-stage upflow anaerobic sludge blanket (UASB) reactor system which was fed with ethanol as the sole
Tuba H Erg³der; Engin G³ven; G÷ksel N Demirer
Nuclear reactor safety system
A safety system (10) for shutting down a nuclear reactor under overload conditions is provided using a series of parallelconnected computing modules (14a, 14b, 14c, 14d, 14e) each of which receives data on a particular reactor parameter (P, t, phi t, phi b, w) and each of which produces a function (F(P), f(T), f( Phi t), f( Phi b), f(W))
A safety system for shutting down a nuclear reactor under overload conditions is provided using a series of parallelconnected computer memory type look-up tables each of which receives data on a particular reactor parameter (P, t, phi t, phi b, w) and each of which has stored therein a precalculated functional value (F(P); f(T); f( Phi t); f( Phi b);
R. M. Ball; R. C. Roberts
Effect of temperature on continuous fermentative lactic acid (LA) production and bacterial community, and development of LA-producing UASB reactor.
A frequently used fermentation manner in lactic acid (LA) production, batch fermentation by pure cultures, has a limited practicability: low volumetric productivity and high energy consumption. In this study, continuous LA fermentation was performed in a completely stirred tank reactor at 12h HRT, inoculated with anaerobic digester sludge. Glucose (25 g COD/L) was used as a feedstock and temperature was increased from 35 to 60░C. LA production significantly increased from 50░C, which was negligible up to 45░C, with obvious bacterial community change. At 50 and 55░C, LA production was maximized, reaching 23 g COD/L, corresponding to 92% LA conversion efficiency. Pyrosequencing analysis showed that microbial diversity was simplified at 50-60░C, and the sequences closely related with Bacillus coagulans became predominant, followed by Lactobacillus fermentum. An LA-producing upflow ananerobic sludge blanket reactor was successfully developed, which enhanced the productivity up to 4.8 gLA/L/h by shortening HRT to 4h. PMID:22750503
Kim, Dong-Hoon; Lim, Wan-Taek; Lee, Mo-Kwon; Kim, Mi-Sun
Moon base reactor system
NASA Technical Reports Server (NTRS)
The objective of our reactor design is to supply a lunar-based research facility with 20 MW(e). The fundamental layout of this lunar-based system includes the reactor, power conversion devices, and a radiator. The additional aim of this reactor is a longevity of 12 to 15 years. The reactor is a liquid metal fast breeder that has a breeding ratio very close to 1.0. The geometry of the core is cylindrical. The metallic fuel rods are of beryllium oxide enriched with varying degrees of uranium, with a beryllium core reflector. The liquid metal coolant chosen was natural lithium. After the liquid metal coolant leaves the reactor, it goes directly into the power conversion devices. The power conversion devices are Stirling engines. The heated coolant acts as a hot reservoir to the device. It then enters the radiator to be cooled and reenters the Stirling engine acting as a cold reservoir. The engines' operating fluid is helium, a highly conductive gas. These Stirling engines are hermetically sealed. Although natural lithium produces a lower breeding ratio, it does have a larger temperature range than sodium. It is also corrosive to steel. This is why the container material must be carefully chosen. One option is to use an expensive alloy of cerbium and zirconium. The radiator must be made of a highly conductive material whose melting point temperature is not exceeded in the reactor and whose structural strength can withstand meteor showers.
Chavez, H.; Flores, J.; Nguyen, M.; Carsen, K.
Implementation of an UASB anaerobic digester at bagasse-based pulp and paper industry
Upflow anaerobic sludge blanket (UASB) reactor was installed to replace the conventional anaerobic lagoon treating bagasse wash wastewater from agro-based pulp and paper mill, to generate bio-energy and to reduce greenhouse gas emissions. The plant was designed to treat 12MLd?1 of wastewater having two 5ML capacity reactors, 5.75kgCODm?3d?1 organic loading rate and 20h hydraulic retention time. In the plant 80¢85%
S. Chinnaraj; G. Venkoba Rao
Sedimentological evolution in an UASB treating SYNTHES, a new representative synthetic sewage, at low loading rates.
The changes in the sedimentological attributes of the sludge bed in an upflow anaerobic sludge blanket (UASB) reactor fed with a low-strength wastewater mimicking raw domestic sewage were assessed in this study. The reactor was inoculated with 250 ml of granular sludge from a full-scale UASB reactor. The organic loading rate (OLR) varied from 1 to 2 g COD/ld. During the half-year long study, the reactor was operated at hydraulic retention times (HRTs) of 4.8 and 10 h, at 33 degrees C. Sludge sedimentology showed that the original granular sludge experienced serious instability and disintegration, leading to a much finer final grain assemblage, mainly due to substrate transfer limitation and cell starvation at the interior of larger granules. With time, the size uniformity tended to decrease, sphericity tended to increase, the skewness of the granule size distribution became negative, and the kurtosis became peaked and leptokurtic. In spite of the observed size reduction, reactor efficiency increased to a CODtotal removal of 96%. Biomass (sludge) yield was 0.012 g VS/g COD removed. The CH4 content of the biogas was high (up to 96%). This study thus highlights the treatment of a new type of wastewater with the deployment of the UASB reactor. It also reports the evolutionary trend of the biomass particle size distribution, making reference to a classic sedimentological appraisal. PMID:15062822
Aiyuk, Sunny; Verstraete, Willy
Comparison of mesophilic and thermophilic upflow anaerobic sludge blanket reactors treating instant coffee production wastewater
Stable anaerobic digestion of settled instant coffee wastewater was achieved for over 100 days in mesophilic (35░C) and termophilic (55░C) UASB reactors. Thermophilic upflow anaerobic sludge blankets (UASBs) were seeded with mesophilic granules and converted to thermophilic operation by raising the temperature to 55░C in one step. Successful thermophilic operation was achieved within 28 days. Both mesophilic and thermophilic UASBs
Richard M. Dinsdale; Freda R. Hawkes; Dennis L. Hawkes
Nuclear reactor coolant transport system
A system for transporting reactor coolant in nuclear reactors using a liquid coolant is described. The system diverts a portion of the output from the main circulating pump in the nuclear reactor primary flow system and introduces this diverted coolant back into the system upstream of the main circulating pump. This diverted coolant compensates for any pressure drop which may
Development of anaerobic sludge bed (ASB) reactor technologies for domestic wastewater treatment: motives and perspectives
During the treatment of raw domestic wastewater in the upflow anaerobic sludge blanket (UASB) reactor, the suspended solids (SS) present in the wastewater tend to influence negatively the methanogenic activity and the chemical oxygen demand (COD) conversion efficiency. These problems led to the emergence of various anaerobic sludge bed systems such as the expanded granular sludge bed (EGSB), the upflow
Youssouf Kalogo; Willy Verstraete
Nuclear reactor sealing system
A liquid metal-cooled nuclear reactor sealing system. The nuclear reactor includes a vessel sealed at its upper end by a closure head. The closure head comprises at least two components, one of which is rotatable; and the two components define an annulus therebetween. The sealing system includes at least a first and second inflatable seal disposed in series in an upper portion of the annulus. The system further includes a dip seal extending into a body of insulation located adjacent a bottom portion of the closure head. The dip seal comprises a trough formed by a lower portion of one of the components, and a seal blade pendently supported from the other component and extending downwardly into the trough. A body of liquid metal is contained in the trough which submerges a portion of the seal blade. The seal blade is provided with at least one aperture located above the body of liquid metal for providing fluid communication between the annulus intermediate the dip seal and the inflatable seals, and a body of cover gas located inside the vessel. There also is provided means for introducing a purge gas into the annulus intermediate the inflatable seals and the seal blade. The purge gas is introduced in an amount sufficient to substantially reduce diffusion of radioactive cover gas or sodium vapor up to the inflatable seals. The purge gas mixes with the cover gas in the reactor vessel where it can be withdrawn from the vessel for treatment and recycle to the vessel.
McEdwards, James A. (Calabasas, CA)
Alternative biological systems for the treatment of vinasse from wine.
This work studied alternative treatment schemes for the vinasse wastewater from wine distilleries aiming at overcoming the problems caused by the high nitrogen and sulfur concentrations. A plexiglas laboratory-scale upflow anaerobic sludge blanket (UASB) reactor of 20 L volume that was operated at 45░C and hydraulic retention time 1 d, was included in all the examined systems. System 1 was the conventional UASB reactor, system 2 was the UASB reactor supplemented with iron. System 3 consisted of the UASB reactor supplemented with iron and a CSTR reactor that operated under the following conditions: Diluted Oxygen 1.2 mg/L, Hydraulic Retention Time 1 d, pH 6.7 and Temperature 45░C. System 3 aimed at converting ammonium directly to dinitrogen gas under anaerobic conditions but it needed to be preceeded by a first partial nitrification step. All systems had high COD efficiencies over 75%. Ferrous iron addition apart from enhancing the performance of systems 2 and 3, it was able to retain all sulphur content of the wastewater as ferrous sulfide stripping the biogas from hydrogen sulfide. System 3 also managed to meet its goal, since it achieved an 86% nitrogen reduction. Conclusively, system 3 seems to be a very promising environmental technology for the treatment of distillery and winery byproducts, as well as industrial wastewater with high sulfur and nitrogen content. PMID:21123920
Vlyssides, A; Barampouti, E M; Mai, S; Stamatoglou, A; Tsimas, E
Anaerobic ammonium oxidation process in an upflow anaerobic sludge blanket reactor with granular sludge selected from an anaerobic digestor
The purpose of this work was to evaluate the development of the anammox process by the use of granular sludge selected from\\u000a a digestion reactor as a potential seed source in a lab-scale UASB (upflow anaerobic sludge blanket) reactor system. The reactor\\u000a was operated for approximately 11 months and was fed by synthetic wastewater. After 200 days of feeding with
Hung-Thuan Tran; Young-Joo Park; Mi-Kyeoung Cho; Dong-Jin Kim; Dae-Hee Ahn
Selected experiences in Chile for the application of UASB technology for vinasse treatment.
One of the research areas is the agricultural use of treated wastewaters, because it represents a unique opportunity to solve the problem of water supply for irrigation and at the same time the disposal of treated water. Anaerobic digestion appears as an interesting alternative, since anaerobically treated wastewaters can be used for irrigation purposes. These considerations are applied to the Chilean pisco industry (a traditional alcoholic drink, prepared by distillation of wine made mainly from Muscatel grapes), where high concentrated wastewaters are produced: vinasses originate as a residue from the distillation operation. Two laboratory reactors fed with wine vinasses, a UASB and an EGSB, were used in order to study the anaerobic treatability of the wastewater. Then, a pilot reactor was built (60 m3 UASB digester) and treated water was used to irrigate eucalyptus trees. Finally a 300 m3 reactor, including biogas treatment for its reuse, was developed. Results showed, both at laboratory and full scale, that anaerobic treatment is suitable for pisco's wastewaters, and also that the nutrient content of treated water can be beneficial for plant growth, reducing the need for fertilizers. Another kind of investigation was carried out in order to study the stability of anaerobic granules and how it can be recovered. UASB and EGSB were fed with low, medium and high load wastewaters, in order to evaluate possible fluctuations in the productive process. From these results, it was possible to propose and to apply recovery techniques to the digesters when they are destabilized. PMID:17849976
Chamy, R; Pizarro, C; Vivanco, E; Schiappacasse, M C; Jeison, D; Poirrier, P; Ruiz-Filippi, G
Attrition reactor system
A reactor vessel for reacting a solid particulate with a liquid reactant has a centrifugal pump in circulatory flow communication with the reactor vessel for providing particulate attrition, resulting in additional fresh surface where the reaction can occur.
Scott, Charles D. (Oak Ridge, TN); Davison, Brian H. (Knoxvile, TN)
Chemical reactor system
US Patent & Trademark Office Database
A reactor comprising an inlet, an outlet, and a conically spiraling fluid flow channel coupled between the inlet and the outlet. The reactor may be an electrochemical reactor comprising a fluid flow channel that spirals about an axis, the fluid flow channel comprising an anode, a cathode across from the anode, and a membrane disposed between the anode and the cathode. The reactor may have a number of design parameters that are based upon one or more reaction species and that favor the occurrence of a reaction associated with the species. The reactor may be used for the electrolysis of water or for the production of other chemical products.
Reactor vessel support system. [LMFBR
A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.
Golden, M.P.; Holley, J.C.
Application of the upflow anaerobic sludge bed (UASB) process for treatment of complex wastewaters at low temperatures
The feasibility of the upflow anaerobic sludge bed (UASB) process for the treatment of potato starch wastewater at low ambient temperatures was demonstrated by operating two 5.65 l reactors at 14 degrees C and 20 degrees C, respectively. The organic space loading rates achieved in these laboratory-scale reactors were 3 kg COD\\/cubic m\\/day at 14 degrees C and 4-5 kg
I. W. Koster; G. Lettinga
Installation of the upflow anaerobic sludge bed (UASB) and expanded granular sludge bed (EGSB) for industrial wastewater has grown very rapid by over the past (15-20 years). The UASB (Upflow Anaerobic Sludge Blanket) process and (EGSB) with high liquid and\\/or gas upflow velocities require biomass with excellent settling characteristics. Typically, granular sludge or anaerobic sludge grown on inorganic support is
Medhat M. A. Saleh; Usama F. Mahmood
Nuclear Reactor Core Clamping System.
The clamping system is for the core of a nuclear reactor having a neutron reflector control system. The clamping system is situated between the core and the reflector system and is of such a size to permit closer spacing of the reflector system to the cor...
R. W. Guenther
Plasma Reactor Waste Management Systems.
The University of North Dakota is developing a plasma reactor system for use in closed-loop processing that includes biological, materials, manufacturing, and waste processing. Direct-current, high-frequency, or microwave discharges will be used to produc...
R. O. Ness J. R. Rindt S. R. Ness
Biohydrogen production and wastewater treatment from organic wastewater by anaerobic fermentation with UASB
In order to discuss the ability of H2-production and wastewater treatment, an up-flow anaerobic sludge bed (UASB) using a synthesized substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, hydrogen producing rate, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. The results show that when the biomass of inoculants was 22.5 g SS.L-1 and the influent concentration, hydraulic retention time (HRT) and initial pH were within the ranges of 4000~6000 mg COD.L-1, 8 h and 5-5.5, respectively, and the biohydrogen producing reactor could work effectively. The maximum hydrogen production rate is 5.98 L.d-1. Simultaneously, the concentration of ethanol and acetic acid is around 80% of the aqueous terminal production in the system, which presents the typical ethanol type fermentation. pH is at the range of 4~4.5 during the whole performing process, however, the removal rate of COD is just about 20%. Therefore, it's still needs further research to successfully achieve the biohydrogen production and wastewater treatment, simultaneously.
Wang, Lu; Li, Yong-Feng; Wang, Yi-Xuan; Yang, Chuan-Ping
The role of sludge retention time in the hydrolysis and acidification of lipids, carbohydrates and proteins during digestion of primary sludge in CSTR systems
The effect of the sludge retention time (SRT) between 3 and 15days, on hydrolysis, acidification and methanogenesis of domestic sewage was researched by simulating a sludge bed segment of an upflow anaerobic sludge bed (UASB) system as a completely stirred tank reactor (CSTR). The CSTR systems were fed with primary sludge (settled solids of domestic sewage) as the influent at
Yehuda Miron; Grietje Zeeman; Jules B van Lier; Gatze Lettinga
Advanced Light Water Reactor Requirements Document: Chapter 4, Reactor Systems.
The purpose of this chapter of the Advanced Light Water Reactor (ALWR) Plant Requirements Document is to establish utility requirements for the design of the Reactor Systems of Advanced LWR plants consistent with the objectives and principles of the ALWR ...
Removal of total coliforms, thermotolerant coliforms, and helminth eggs in Swine production wastewater treated in anaerobic and aerobic reactors.
The present work evaluated the performance of two treatment systems in reducing indicators of biological contamination in swine production wastewater. System I consisted of two upflow anaerobic sludge blanket (UASB) reactors, with 510 and 209?L in volume, being serially arranged. System II consisted of a UASB reactor, anaerobic filter, trickling filter, and decanter, being also organized in series, with volumes of 300, 190, 250, and 150?L, respectively. Hydraulic retention times (HRT) applied in the first UASB reactors were 40, 30, 20, and 11?h in systems I and II. The average removal efficiencies of total and thermotolerant coliforms in system I were 92.92% to 99.50% and 94.29% to 99.56%, respectively, and increased in system II to 99.45% to 99.91% and 99.52% to 99.93%, respectively. Average removal rates of helminth eggs in system I were 96.44% to 99.11%, reaching 100% as in system II. In reactor sludge, the counts of total and thermotolerant coliforms ranged between 10(5) and 10(9)?MPN (100?mL)(-1), while helminth eggs ranged from 0.86 to 9.27?eggs?g(-1)?TS. PMID:24812560
Zacarias Sylvestre, Silvia Helena; Lux Hoppe, Estevam Guilherme; de Oliveira, Roberto Alves
Removal of Total Coliforms, Thermotolerant Coliforms, and Helminth Eggs in Swine Production Wastewater Treated in Anaerobic and Aerobic Reactors
The present work evaluated the performance of two treatment systems in reducing indicators of biological contamination in swine production wastewater. System I consisted of two upflow anaerobic sludge blanket (UASB) reactors, with 510 and 209?L in volume, being serially arranged. System II consisted of a UASB reactor, anaerobic filter, trickling filter, and decanter, being also organized in series, with volumes of 300, 190, 250, and 150?L, respectively. Hydraulic retention times (HRT) applied in the first UASB reactors were 40, 30, 20, and 11?h in systems I and II. The average removal efficiencies of total and thermotolerant coliforms in system I were 92.92% to 99.50% and 94.29% to 99.56%, respectively, and increased in system II to 99.45% to 99.91% and 99.52% to 99.93%, respectively. Average removal rates of helminth eggs in system I were 96.44% to 99.11%, reaching 100% as in system II. In reactor sludge, the counts of total and thermotolerant coliforms ranged between 105 and 109?MPN (100?mL)?1, while helminth eggs ranged from 0.86 to 9.27?eggs?g?1?TS.
Reactor refueling containment system
A method of refueling a nuclear reactor whereby the drive mechanism is disengaged and removed by activating a jacking mechanism that raises the closure head. The area between the barrier plate and closure head is exhausted through the closure head penetrations. The closure head, upper drive mechanism, and bellows seal are lifted away and transported to a safe area. The barrier plate acts as the primary boundary and each drive and control rod penetration has an elastomer seal preventing excessive tritium gases from escaping. The individual instrumentation plugs are disengaged allowing the corresponding fuel assembly to be sealed and replaced.
Gillett, James E. (Greensburg, PA); Meuschke, Robert E. (Pittsburgh, PA)
A method of refueling a nuclear reactor is disclosed whereby the drive mechanism is disengaged and removed by activating a jacking mechanism that raises the closure head. The area between the barrier plate and closure head is exhausted through the closure head penetrations. The closure head, upper drive mechanism, and bellows seal are lifted away and transported to a safe area. The barrier plate acts as the primary boundary and each drive and control rod penetration has an elastomer seal preventing excessive tritium gases from escaping. The individual instrumentation plugs are disengaged allowing the corresponding fuel assembly to be sealed and replaced. 2 figs.
Gillett, J.E.; Meuschke, R.E.
Reactor core isolation cooling system
A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom. 1 figure.
Cooke, F.E.
A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom.
Cooke, Franklin E. (San Jose, CA)
Decolorization and COD reduction of UASB pretreated poultry manure wastewater by electrocoagulation process: A post-treatment study
The performance of electrocoagulation (EC) technique for decolorization and chemical oxygen demand (COD) reduction of anaerobically pretreated poultry manure wastewater was investigated in a laboratory batch study. Two identical 15.7-L up-flow anaerobic sludge blanket (UASB) reactors were first run under various organic and hydraulic loading conditions for 216 days. Effects of operating parameters such as type of sacrificial electrode material,
Kaan Yetilmezsoy; Fatih Ilhan; Zehra Sapci-Zengin; Suleyman Sakar; M. Talha Gonullu
Start-up procedures and analysis of heavy metals inhibition on methanogenic activity in EGSB reactor.
The effectiveness of operating an industrial UASB reactor, treating wastewater from the beer industry, with flows containing heavy metals was evaluated. A pilot-scale UASB reactor, already used to simulate the industrial reactor, was unsuccessfully employed. An easy start-up was obtained arranging it as an EGSB reactor. Considerations about this modification are reported. The effects of Cu(II), Ni(II) and Cr(III) ions on the anaerobic activity were analyzed by measurements of methane production rate and COD removal. The employed biomass was the sludge of the industrial UASB reactor, while a solution of ethanol and sodium acetate with COD of 3000 mg/L and a heavy metal concentration of 50 mg/L were continuously fed. Experimental results proved higher biomass sensitivity for copper and much slighter for nickel and chromium. Moreover, copper inhibition has been demonstrated to be less significant if a metal-free feed was provided to the system before copper addition. PMID:19679466
Colussi, I; Cortesi, A; Della Vedova, L; Gallo, V; Robles, F K Cano
Plasma reactor waste management systems
The University of North Dakota is developing a plasma reactor system for use in closed-loop processing that includes biological, materials, manufacturing, and waste processing. Direct-current, high-frequency, or microwave discharges will be used to produce plasmas for the treatment of materials. The plasma reactors offer several advantages over other systems, including low operating temperatures, low operating pressures, mechanical simplicity, and relatively safe operation. Human fecal material, sunflowers, oats, soybeans, and plastic were oxidized in a batch plasma reactor. Over 98 percent of the organic material was converted to gaseous products. The solids were then analyzed and a large amount of water and acid-soluble materials were detected. These materials could possibly be used as nutrients for biological systems.
Ness, Robert O., Jr.; Rindt, John R.; Ness, Sumitra R.
Analysis of microbial characterization in an upflow anaerobic sludge bed/biological aerated filter system for treating microcrystalline cellulose wastewater.
A two-stage UASB and 2-stage BAF series bioreactor was used for treating the microcrystalline cellulose (MCC) wastewater. The treating efficiency, dominant microbes, eubacterial and archaebacterial composition and cel5A, cel6B and bglC gene expression levels were examined using combined PCR-DGGE and real-time PCR technology. The results showed that under three MCC loads (1000, 2000 and 3000 mg L(-1)), the total MCC degradation efficiency of the UASB-BAF system was 82.0%, 83.5% and 70.5%, respectively. In different MCC load cases, the first stage UASB and BAF formed an approximate full-value cellulase system where cellulolytic microorganisms were the dominant flora, while the second stage UASB and BAF formed a low-value cellulase system where non-cellulolytic microorganisms were the dominant flora. Eubacteria were dominant in every UASB-BAF unit. The rate-limiting enzyme gene for MCC degradation in every unit was cel6B. These results will support the development of high efficiency bio-reactors for the degradation of MCC. PMID:22784954
Ji, Guodong; Wu, Yingchao; Wang, Chen
Rapid starting methanol reactor system
The invention relates to a methanol-to-hydrogen cracking reactor for use with a fuel cell vehicular power plant. The system is particularly designed for rapid start-up of the catalytic methanol cracking reactor after an extended shut-down period, i.e., after the vehicular fuel cell power plant has been inoperative overnight. Rapid system start-up is accomplished by a combination of direct and indirect heating of the cracking catalyst. Initially, liquid methanol is burned with a stoichiometric or slightly lean air mixture in the combustion chamber of the reactor assembly. The hot combustion gas travels down a flue gas chamber in heat exchange relationship with the catalytic cracking chamber transferring heat across the catalyst chamber wall to heat the catalyst indirectly. The combustion gas is then diverted back through the catalyst bed to heat the catalyst pellets directly. When the cracking reactor temperature reaches operating temperature, methanol combustion is stopped and a hot gas valve is switched to route the flue gas overboard, with methanol being fed directly to the catalytic cracking reactor. Thereafter, the burner operates on excess hydrogen from the fuel cells.
Chludzinski, Paul J. (38 Berkshire St., Swampscott, MA 01907); Dantowitz, Philip (39 Nancy Ave., Peabody, MA 01960); McElroy, James F. (12 Old Cart Rd., Hamilton, MA 01936)
Solvent refined coal reactor quench system
There is described an improved SRC reactor quench system using a condensed product which is recycled to the reactor and provides cooling by evaporation. In the process, the second and subsequent reactors of a series of reactors are cooled by the addition of a light oil fraction which provides cooling by evaporation in the reactor. The vaporized quench liquid is recondensed from the reactor outlet vapor stream.
Thorogood, Robert M. (Macungie, PA)
Reactor control rod timing system
A fluid driven jet-edge whistle timing system for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.
Wu, Peter T. K. (Clifton Park, NY)
Treatment of domestic wastewater in an up-flow anaerobic sludge blanket reactor followed by moving bed biofilm reactor
The performance of a laboratory-scale sewage treatment system composed of an up-flow anaerobic sludge blanket (UASB) reactor\\u000a and a moving bed biofilm reactor (MBBR) at a temperature of (22¢35Ā░C) was evaluated. The entire treatment system was operated\\u000a at different hydraulic retention times (HRTÆs) of 13.3, 10 and 5.0Āh. An overall reduction of 80¢86% for CODtotal; 51¢73% for CODcolloidal and 20¢55%
A. Tawfik; F. El-Gohary; H. Temmink
Reactor vessel annealing system
A system for annealing a vessel (14) in situ by heating the vessel (14) to a defined temperature, composed of: an electrically operated heater assembly (10) insertable into the vessel (14) for heating the vessel (14) to the defined temperature; temperature monitoring components positioned relative to the heater assembly (10) for monitoring the temperature of the vessel (14); a controllable electric power supply unit (32-60) for supplying electric power required by the heater assembly (10); a control unit (80-86) for controlling the power supplied by the power supply unit (32-60); a first vehicle (2) containing the power supply unit (32-60); a second vehicle (4) containing the control unit (80-86); power conductors (18,22) connectable between the power supply unit (32-60) and the heater unit (10) for delivering the power supplied by the power supply unit (32-60) to the heater assembly (10); signal conductors (20,24) connectable between the temperature monitoring components and the control unit (80-86) for delivering temperature indicating signals from the temperature monitoring components to the control unit (80-86); and control conductors (8) connectable between the control unit (80-86) and the power supply unit (32-60) for delivering to the power supply unit (32-60) control signals for controlling the level of power supplied by the power supply unit (32-60) to the heater assembly (10).
Miller, Phillip E. (Greensburg, PA); Katz, Leonoard R. (Pittsburgh, PA); Nath, Raymond J. (Murrysville, PA); Blaushild, Ronald M. (Export, PA); Tatch, Michael D. (Randolph, NJ); Kordalski, Frank J. (White Oak, PA); Wykstra, Donald T. (Pittsburgh, PA); Kavalkovich, William M. (Monroeville, PA)
Performance and model of a full-scale up-flow anaerobic sludge blanket (UASB) to treat the pharmaceutical wastewater containing 6-APA and amoxicillin.
A full-scale test was conducted with an up-flow anaerobic sludge blanket (UASB) pre-treating pharmaceutical wastewater containing 6-aminopenicillanic acid (6-APA) and amoxicillin. The aim of the study is to investigate the performance of UASB in the condition of a high chemical oxygen demand (COD) loading rate from 12.57 to 21.02 kgm(-3)d(-1) and a wide pH from 5.57 to 8.26, in order to provide a reference for treating the similar chemical synthetic pharmaceutical wastewater containing 6-APA and amoxicillin. The results demonstrated that the UASB average percentage reduction in COD, 6-APA and amoxicillin were 52.2%, 26.3% and 21.6%, respectively. In addition, three models, built on the back propagation neural network (BPNN) theory and linear regression techniques were developed for the simulation of the UASB system performance in the biodegradation of pharmaceutical wastewater containing 6-APA and amoxicillin. The average error of COD, 6-APA and amoxicillin were -0.63%, 2.19% and 5.40%, respectively. The results indicated that these models built on the BPNN theory were well-fitted to the detected data, and were able to simulate and predict the removal of COD, 6-APA and amoxicillin by UASB. PMID:20970923
Chen, Zhiqiang; Wang, Hongcheng; Chen, Zhaobo; Ren, Nanqi; Wang, Aijie; Shi, Yue; Li, Xiaoming
Fuel transfer system for a nuclear reactor
Disclosed is a fuel transfer system for moving nuclear reactor fuel assemblies from a new fuel storage pit to a containment area containing the nuclear reactor, and for transferring spent fuel assemblies under water from the reactor to a spent fuel storage area. The system includes an underwater track which extends through a wall dividing the fuel building from the
L. R. Katz; J. R. Marshall; W. E. Desmarchais
A fuel transfer system is described for moving nuclear reactor fuel assemblies from a new fuel storage pit to a containment area containing the nuclear reactor, and for transferring spent fuel assemblies under water from the reactor to a spent fuel storage area. The system includes an underwater track which extends through a wall dividing the fuel building from the
L. R. Katz; J. R. Marshall; W. Desmarchais
Start-up of an UASB-septic tank for community on-site treatment of strong domestic sewage.
Two community on-site UASB-septic tanks were operated in parallel over a six months period under two different hydraulic retention times (HRT) of 2 days for R1 and 4 days for R2 at mean sewage temperature of 24 degrees C. The sewage was characterised by a high COD(tot) concentration of 1189 mg/L, with a large fraction of COD(sus), viz. 54%. The achieved removal efficiencies in R1 and R2 for COD(tot), COD(sus), BOD5 and TSS were "56%, 87%, 59% and 81%" and "58%, 90%, 60% and 82%" for both systems, respectively. R2 achieved a marginal but significant (p<0.05) better removal efficiencies of those parameters as compared to R1. The COD(col) and COD(dis) removals in R1 and R2 were respectively 31% and 20%, and 34% and 22%. The sludge accumulation was very low suggesting that the desludging frequency will be of several years. Accordingly, the reactor can be adequately designed at 2 days HRT. PMID:18321699
Al-Shayah, Mohammad; Mahmoud, Nidal
Start-up procedures and analysis of heavy metals inhibition on methanogenic activity in EGSB reactor
The effectiveness of operating an industrial UASB reactor, treating wastewater from the beer industry, with flows containing heavy metals was evaluated. A pilot-scale UASB reactor, already used to simulate the industrial reactor, was unsuccessfully employed. An easy start-up was obtained arranging it as an EGSB reactor. Considerations about this modification are reported. The effects of Cu(II), Ni(II) and Cr(III) ions
I. Colussi; A. Cortesi; L. Della Vedova; V. Gallo; F. K. Cano Robles
Shutdown system for a nuclear reactor
An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion.
Groh, Edward F. (Naperville, IL); Olson, Arne P. (Western Springs, IL); Wade, David C. (Naperville, IL); Robinson, Bryan W. (Oak Lawn, IL)
Biodegradation of tetrachloroethylene in upflow anaerobic sludge blanket reactor
The laboratory study using upflow anaerobic sludge blanket (UASB) reactor in high strength wastewater containing tetrachloroethylene (PCE) was carried out to develop granular sludge in the presence of PCE (2 mg\\/l) and to assess the potential of UASB reactor in treating PCE containing wastewater. The granules of 0.25¢4 mm size were observed after 82 days having mostly Methanothrix and Methanosarcina
S. M. Prakash; S. K. Gupta
Tandem Mirror Reactor Systems Code (Version I)
A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost.
Reid, R.L.; Finn, P.A.; Gohar, M.Y.; Barrett, R.J.; Gorker, G.E.; Spampinaton, P.T.; Bulmer, R.H.; Dorn, D.W.; Perkins, L.J.; Ghose, S.
Characteristics of Two-Reactor Electronuclear Systems
The Monte Carlo method is used to simulate electronuclear systems consisting of two-cascade subcritical zones: a liquid-metal fast reactor, which is used as a booster, and a thermal reactor, where most of the energy is released. Reactors of the type VV╔R-1000, MSBR-1000, and CANDU-6 are considered. The systems considered, functioning in the safe regime (keff = 0.94¢0.98), possess much higher
S. A. Bznuni; V. M. Zhamkochyan; A. G. Khudaverdyan; V. S. Barashenkov; A. N. Sosnin; A. Polyanski
Nuclear electric propulsion reactor control systems status
The thermionic reactor control system design studies conducted over the past several years for a nuclear electric propulsion system are described and summarized. The relevant reactor control system studies are discussed in qualitative terms, pointing out the significant advantages and disadvantages including the impact that the various control systems would have on the nuclear electric propulsion system design. A recommendation for the reference control system is made, and a program for future work leading to an engineering model is described.
Ferg, D. A.
A mesophilic(35℃) UASB reactor treating synthetic wastewater containing methanol with addition of starch was continuously operated for over 430 days by changing the organic loading rate from 2.5 to 120kg-COD/m3.d. The microbial community structure of the granules was analyzed with the molecular tools and its metabolic characteristics were evaluated using specific methanogenic activity tests. The process was successfully operated with over 98% soluble COD removal efficiency at VLR 30kg-COD/m3.d for approximately 300 days, and granulation satisfactory proceeded. The results of cloning and fluorescence in situ hybridization analysis suggest that groups related the genus Methanomethylovorans and the genus Methanosaeta were predominant in the reactor although only the genus Methanomethylovorans was predominant in the reactor treating methanolic wastewater in the previous study. Abundance of the granules over 0.5 mm in diameter in the reactor treating methanolic wastewater with addition of starch was 3 times larger than that in the reactor treating methanolic wastewater. Specific methanogenic activity tests in this study indicate that the methanol-methane pathway and the methanol-H2/CO2-methane pathway were predominant, and however, there was a certain level of activity for acetate-methane pathway unlike the reactor treating methanolic wastewater. These results suggest addition of starch might be responsible for diversifying the microbial community and encouraging the granulation.
Yan, Feng; Kobayashi, Takuro; Takahashi, Shintaro; Li, Yu-You; Omura, Tatsuo
Effect of wastewater composition on the calcium carbonate precipitation in upflow anaerobic sludge blanket reactors
Calcium carbonate often precipitates in anaerobic reactors treating wastewater with high calcium content. The aim of this\\u000a paper is to study the effect of wastewater composition on calcium carbonate precipitation in upflow anaerobic sludge blanket\\u000a (UASB) reactors. Two laboratory-scale UASB reactors were operated with calcium-containing influents using acetate and carbohydrate\\u000a as substrate, respectively. There was an obvious accumulation of inorganic
Shucheng Yang; Yanling He; Yonghong Liu; Charles Chou; Pengxiang Zhang; Dongqi Wang
The 5-kwe reactor thermoelectric system summary
Design of the 5-kwe reactor thermoelectric system was initiated in February 1972 and extended through the conceptual design phase into the preliminary design phase. Design effort was terminated in January, 1973. This report documents the system and component requirements, design approaches, and performance and design characteristics for the 5-kwe system. Included is summary information on the reactor, radiation shields, power conversion systems, thermoelectric pump, radiator/structure, liquid metal components, and the control system.
Vanosdol, J. H. (editor)
Reactor technology: power conversion systems and reactor operation and maintenance
The use of advanced fuels permits the use of coolants (organic, high pressure helium) that result in power conversion systems with good thermal efficiency and relatively low cost. Water coolant would significantly reduce thermal efficiency, while lithium and salt coolants, which have been proposed for DT reactors, will have comparable power conversion efficiencies, but will probably be significantly more expensive.
Reductive decolourisation of sulphonated mono and diazo dyes in one- and two-stage anaerobic systems.
This work assessed the application of one- and two-stage mesophilic anaerobic systems to colour removal of sulphonated mono and diazo dyes with ethanol as electron donor. The dyes Congo Red (CR), Reactive Black 5 (RB5) and Reactive Red 2 (RR2) were selected as model compounds and tested separately in seven different periods. The one-stage system (R(1)) consisted of a single up-flow anaerobic sludge blanket (UASB) reactor, whereas the two-stage system (R(2)) consisted of an acidogenic UASB reactor (R(A)), a settler and a methanogenic UASB reactor (R(M)). For CR and RB5, no remarkable difference was observed between the colour removal performance of both anaerobic systems R(1) and R(2). The experiments with RR2 revealed that R(2) was more efficient on colour removal than R(1), showing efficiencies almost 2-fold (period VI) and 2.5-fold (period VII) higher than those found by R(1). Additionally, R(2) showed a higher stability, giving a good prospect for application to textile wastewaters. Finally, the acidogenic reactor (R(A)) had an important role in the overall decolourisation achieved by R(2) during the experiments with CR and RB5 (>78 %), whereas for RR2, a more recalcitrant dye, R(A) was responsible for up to 38 % of the total colour removal. PMID:23456307
da Silva, Marcos Erick Rodrigues; Firmino, Paulo Igor Milen; dos Santos, Andrķ Bezerra
TREAT Reactor Control and Protection System
The main control algorithm of the Transient Reactor Test Facility (TREAT) Automatic Reactor Control System (ARCS) resides in Read Only Memory (ROM) and only experiment specific parameters are input via keyboard entry. Prior to executing an experiment, the software and hardware of the control computer is tested by a closed loop real-time simulation. Two computers with parallel processing are used for the reactor simulation and another computer is used for simulation of the control rod system. A monitor computer, used as a redundant diverse reactor protection channel, uses more conservative setpoints and reduces challenges to the Reactor Trip System (RTS). The RTS consists of triplicated hardwired channels with one out of three logic. The RTS is automatically tested by a digital Dedicated Microprocessor Tester (DMT) prior to the execution of an experiment. 6 refs., 5 figs., 1 tab.
Lipinski, W.C.; Brookshier, W.K.; Burrows, D.R.; Lenkszus, F.R.; McDowell, W.P.
Biofilm Reactor for a Bacteria Fuel Cell System.
A biofilm reactor has been investigated to replace a traditional bioreactor for a bacterial fuel cell system. In the fuel cell system studied, the biofilm reactor is used to separate biological reaction from electrode (anode) reaction. The reactor is made...
X. Zhang A. Halme
Performance of the PRISM (power reactor - innovative, small module) reactor's passive decay heat removal system
The PRISM (power reactor - innovative, small module) modular reactor concept has a totally passive decay heat removal system referred to as the reactor vessel auxiliary cooling system (RVACS) that rejects heat from the reactor by radiation and natural convection of air. The system is inherently reliable and is not subject to the failure modes commonly associated with active cooling
P. M. Magee; A. Hunsbedt
Flexible Conversion Ratio Fast Reactor Systems Evaluation
Conceptual designs of lead-cooled and liquid salt-cooled fast flexible conversion ratio reactors were developed. Both concepts have cores reated at 2400 MWt placed in a large-pool-type vessel with dual-free level, which also contains four intermediate heat exchanges coupling a primary coolant to a compact and efficient supercritical CO2 Brayton cycle power conversion system. Decay heat is removed passively using an enhanced Reactor Vessel Auxiliary Cooling System and a Passive Secondary Auxiliary Cooling System. The most important findings were that (1) it is feasible to design the lead-cooled and salt-cooled reactor with the flexible conversion ratio (CR) in the range of CR=0 and CR=1 n a manner that achieves inherent reactor shutdown in unprotected accidents, (2) the salt-cooled reactor requires Lithium thermal Expansion Modules to overcme the inherent salt coolant's large positive coolant temperature reactivity coefficient, (3) the preferable salt for fast spectrum high power density cores is NaCl-Kcl-MgCl2 as opposed to fluoride salts due to its better themal-hydraulic and neutronic characteristics, and (4) both reactor, but attain power density 3 times smaller than that of the sodium-cooled reactor.
Neil Todreas; Pavel Hejzlar
Fluidized-Bed Reactor System
Gas pyrolysis in hot fluidized beds minimized by use of selectively filtered radiation and parabolic cavity. Reactor is parabolic cavity of two or more axes in which light emanating from one axis bounces off walls of cavity and passes through object axis to heat sample.
Morrison, A. D.
Effects of Fe2+ on sludge granulation in upflow anaerobic sludge blanket reactors
Abstract Experiments were performed in parallel using six identical UASB (upflow anaerobic sludge blanket) reactors to examine the effects of iron (Fe,) on sludge granulation during start-up. Introduction of Fe, at concentrations of 300 and 450 mg\\/L enhanced the granulation process in UASB reactors, while dosage of Fe, (150 mg\\/L) had little effect on the sludge granulation. The Fe,concentration in
H. Q. Yu; H. H. P. Fang; J. H. Tay
Biogas production from supernatant of hydrothermally treated municipal sludge by upflow anaerobic sludge blanket reactor
The supernatant of hydrothermally treated sludge was treated by an upflow anaerobic sludge blanket (UASB) reactor for a 550-days running test. The hydrothermal parameter was 170░C for 60min. An mesophilic 8.6L UASB reactor was seeded with floc sludge. The final organic loading rate (OLR) could reach 18kg COD\\/m3d. At the initial stage running for 189days, the feed supernatant was diluted,
Wei Qiao; Chong Peng; Wei Wang; ZhongZhi Zhang
10 CFR 50.46a - Acceptance criteria for reactor coolant system venting systems.
Code of Federal Regulations, 2010 CFR
...Regulatory Approvals ┬¦ 50.46a Acceptance criteria for reactor coolant system venting systems. Each nuclear power reactor must be provided with high point vents for the reactor coolant system, for the reactor vessel head, and for...
Control system for a small fission reactor
A system for controlling the reactivity of a small fission reactor includes an elongated, flexible hollow tube in the general form of a helical coiled spring axially positioned around and outside of the reactor vessel in an annular space between the reactor vessel and a surrounding cylindrical-shaped neutron reflector. A neutron absorbing material is provided within the hollow tube with the rate of the reaction controlled by the extension and compression of the hollow tube, e.g., extension of the tube increases reactivity while its compression reduces reactivity, in varying the amount of neutron absorbing material disposed between the reactor vessel and the neutron reflector. Conventional mechanical displacement means may be employed to control the coil density of the hollow tube as desired. In another embodiment, a plurality of flexible hollow tubes each containing a neutron absorber are positioned adjacent to one another in spaced relation around the periphery of the reactor vessel and inside the outer neutron reflector with reactivity controlled by the extension and compression of all or some of the coiled hollow tubes. Yet another embodiment of the invention envisions the neutron reflector in the form of an expandable coil spring positioned in an annular space between the reactor vessel and an outer neutron absorbing structure for controlling the neutron flux reflected back into the reactor vessel.
Burelbach, James P. (Glen Ellyn, IL) [Glen Ellyn, IL; Kann, William J. (Park Ridge, IL) [Park Ridge, IL; Saiveau, James G. (Hickory Hills, IL) [Hickory Hills, IL
A system for controlling the reactivity of a small fission reactor includes an elongated, flexible hollow tube in the general form of a helical coiled spring axially positioned around and outside of the reactor vessel in an annular space between the reactor vessel and a surrounding cylindrical-shaped neutron reflector. A neutron absorbing material is provided within the hollow tube with the rate of the reaction controlled by the extension and compression of the hollow tube, e.g., extension of the tube increases reactivity while its compression reduces reactivity, in varying the amount of neutron absorbing material disposed between the reactor vessel and the neutron reflector. Conventional mechanical displacement means may be employed to control the coil density of the hollow tube as desired.
Burelbach, J.P.; Kann, W.J.; Saiveau, J.G.
Extended SP-100 reactor power systems capability
The SP-100 space nuclear power system development program and the NASA Civil Space Technology Initiative (CSTI) are discussed. The advanced technologies being developed for the CSTI high capacity nuclear reactor power system are outlined. The relationship between the CSTI and the Pathfinder project is considered.
Bloomfield, H. S.; Winter, J. M.; Mckissock, B. I.; Sovie, R. J.
Nuclear reactor containment spray testing system. [PWR
Disclosed is a method for periodic testing of a spray system in a nuclear reactor containment. The method includes injecting a gas into the spray system such that a temperature differential exists between the gas and the containment atmosphere. Scanning the gas jet discharged from the spray nozzles with infrared apparatus then provides a real-time thermal image on a monitor,
Reactor Protection System Including Engineered Features Actuation System.
The safety concept requires to ensure that - the reactor protection system - the active engineered safeguard - and the necessary auxiliary systems are so designed and interfaced in respect of design and mode of action that, in the event of single componen...
W. Palmaers
Effect of chitosan on UASB treating POME during a transition from mesophilic to thermophilic conditions.
The effects of chitosan addition on treatment of palm oil mill effluent were investigated using two lab-scale upflow anaerobic sludge bed (UASB) reactors: (1) with chitosan addition at the dosage of 2 mg chitosan per g volatile suspended solids on the first day of the operation (R1), (2) without chitosan addition (the control, R2). The reactors were inoculated with mesophilic anaerobic sludge which was acclimatized to a thermophilic condition with a stepwise temperature increase of 5 ░C from 37 to 57 ░C. The OLR ranged from 2.23 to 9.47 kg COD m(-3) day(-1). The difference in biogas production rate increased from non-significant to 18% different. The effluent volatile suspended solids of R1 was 65 mg l(-1) lower than that of R2 on Day 123. 16S rRNA targeted denaturing gradient gel electrophoresis (DGGE) fingerprints of microbial community indicated that some methanogens in the genus Methanosaeta can be detected in R1 but not in R2. PMID:21316949
Khemkhao, Maneerat; Nuntakumjorn, Boonyarit; Techkarnjanaruk, Somkiet; Phalakornkule, Chantaraporn
Emergency core cooling system for a nuclear reactor
An emergency core cooling system for a nuclear reactor which preferably is supplemental to the main emergency core cooling system incorporated in the reactor at the time of construction is described. Under circumstances of a rupture in the reactor primary coolant piping and consequent drop in reactor coolant pressure, emergency supplemental coolant is supplied from tanks or accumulators through check
W. E. Desmarchais; L. R. Katz; B. L. Silverblatt
Advanced thermionic reactor systems design code
An overall systems design code is under development to model an advanced in-core thermionic nuclear reactor system for space applications at power levels of 10 to 50 kWe. The design code is written in an object-oriented programming environment that allows the use of a series of design modules, each of which is responsible for the determination of specific system parameters.
Bryan R. Lewis; Ronald A. Pawlowski; Kevin J. Greek; Andrew C. Klein
Reliability Assessment of SMART Reactor Protection System
Component failure rates and integrated system reliability of the SMART reactor protection system were analyzed. The analysis tool of the study was the RELEX 7 computer program developed by Relex Software Corporation. The RELEX software is a PC based computer program which includes the part stress analysis models and the RBD analysis model to calculate component and system reliability. The component failure rate data for the study was selected from the MIL-HDBK-217F. (authors)
Won Young, Yun; Choong Heui, Jeong [Korea Institute of Nuclear Safety, P. O. Box 114, Yusong Post Office, Daejeon (Korea, Republic of); Seong Hun, Kim; Sang Yong, Lee [Sam Chang Enterprise Co. LTD, 974-1, Goyen-ri, Woongchon-myon, Ulju-gun, Ulsan (Korea, Republic of)
Gaseous fuel reactors for power systems
The Los Alamos Scientific Laboratory is participating in a NASA-sponsored program to demonstrate the feasibility of a gaseous uranium fueled reactor. The work is aimed at acquiring experimental and theoretical information for the design of a prototype plasma core reactor which will test heat removal by optical radiation. The basic goal of this work is for space applications, however, other NASA-sponsored work suggests several attractive applications to help meet earth-bound energy needs. Such potential benefits are: small critical mass, on-site fuel processing, high fuel burnup, low fission fragment inventory in reactor core, high temperature for process heat, optical radiation for photochemistry and space power transmission, and high temperature for advanced propulsion systems.
Helmick, H. H.; Schwenk, F. C.
Gaseous fuel reactor systems for aerospace applications
Research on the gaseous fuel nuclear rocket concept continues under the programs of the U.S. National Aeronautics and Space Administration (NASA) Office for Aeronautics and Space Technology and now includes work related to power applications in space and on earth. In a cavity reactor test series, initial experiments confirmed the low critical mass determined from reactor physics calculations. Recent work with flowing UF6 fuel indicates stable operation at increased power levels. Preliminary design and experimental verification of test hardware for high-temperature experiments have been accomplished. Research on energy extraction from fissioning gases has resulted in lasers energized by fission fragments. Combined experimental results and studies indicate that gaseous-fuel reactor systems have significant potential for providing nuclear fission power in space and on earth.
Thom, K.; Schwenk, F. C.
Reactor control rod timing system. [LMFBR
A fluid driven jet-edge whistle timing system is described for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.
Wu, P.T.K.
Control system studies for thermionic reactors
In core thermionic reactor concepts are of interest for space missions that require electrical power in the range of a few tens of kilowatts up to several megawatts. The physical principle involved--thermionic direct conversion of heat to electricity at net efficiencies up to 15 percent--offers potential advantages when compared to other nuclear powerplant concepts. However, the integration of the thermionic diode electrode structure with high-temperature nuclear fuel materials presents new design problems and new reactor physical constraints. Among the topics that must be investigated are those associated with the control system. The results of analytical and simulation studies of thermionic reactor control performed at the Jet Propulsion Laboratory are discussed.
Hermsen, R. J.; Gronroos, H. G.
Fault-tolerant reactor protection system
A reactor protection system having four divisions, with quad redundant sensors for each scram parameter providing input to four independent microprocessor-based electronic chassis. Each electronic chassis acquires the scram parameter data from its own sensor, digitizes the information, and then transmits the sensor reading to the other three electronic chassis via optical fibers. To increase system availability and reduce false scrams, the reactor protection system employs two levels of voting on a need for reactor scram. The electronic chassis perform software divisional data processing, vote 2/3 with spare based upon information from all four sensors, and send the divisional scram signals to the hardware logic panel, which performs a 2/4 division vote on whether or not to initiate a reactor scram. Each chassis makes a divisional scram decision based on data from all sensors. Each division performs independently of the others (asynchronous operation). All communications between the divisions are asynchronous. Each chassis substitutes its own spare sensor reading in the 2/3 vote if a sensor reading from one of the other chassis is faulty or missing. Therefore the presence of at least two valid sensor readings in excess of a set point is required before terminating the output to the hardware logic of a scram inhibition signal even when one of the four sensors is faulty or when one of the divisions is out of service.
Gaubatz, Donald C. (Cupertino, CA)
A reactor protection system is disclosed having four divisions, with quad redundant sensors for each scram parameter providing input to four independent microprocessor-based electronic chassis. Each electronic chassis acquires the scram parameter data from its own sensor, digitizes the information, and then transmits the sensor reading to the other three electronic chassis via optical fibers. To increase system availability and reduce false scrams, the reactor protection system employs two levels of voting on a need for reactor scram. The electronic chassis perform software divisional data processing, vote 2/3 with spare based upon information from all four sensors, and send the divisional scram signals to the hardware logic panel, which performs a 2/4 division vote on whether or not to initiate a reactor scram. Each chassis makes a divisional scram decision based on data from all sensors. Each division performs independently of the others (asynchronous operation). All communications between the divisions are asynchronous. Each chassis substitutes its own spare sensor reading in the 2/3 vote if a sensor reading from one of the other chassis is faulty or missing. Therefore the presence of at least two valid sensor readings in excess of a set point is required before terminating the output to the hardware logic of a scram inhibition signal even when one of the four sensors is faulty or when one of the divisions is out of service. 16 figs.
Gaubatz, D.C.
Reactor power system deployment and startup
This paper addresses issues that should receive further examination in the near-term as concept selection for development of a U.S. space reactor power system is approached. The issues include: the economics, practicality and system reliability associated with transfer of nuclear spacecraft from low earth shuttle orbits to operational orbits, via chemical propulsion versus nuclear electric propulsion; possible astronaut supervised reactor and nuclear electric propulsion startup in low altitude Shuttle orbit; potential deployment methods for nuclear powered spacecraft from Shuttle; the general public safety of low altitude startup and nuclear safe and disposal orbits; the question of preferred reactor power level; and the question of frozen versus molten alkali metal coolant during launch and deployment. These issues must be considered now because they impact the SP-100 concept selection, power level selection, weight and size limits, use of deployable radiators, reliability requirements, and economics, as well as the degree of need for and the urgency of developing space reactor power systems.
Wetch, J. R.; Nelin, C. J.; Britt, E. J.; Klein, G.
Containment system for supercritical water oxidation reactor
A system for containment of a supercritical water oxidation reactor in the event of a rupture of the reactor. The system includes a containment for housing the reaction vessel and a communicating chamber for holding a volume of coolant, such as water. The coolant is recirculated and sprayed to entrain and cool any reactants that might have escaped from the reaction vessel. Baffles at the entrance to the chamber prevent the sprayed coolant from contacting the reaction vessel. An impact-absorbing layer is positioned between the vessel and the containment to at least partially absorb momentum of any fragments propelled by the rupturing vessel. Remote, quick-disconnecting fittings exterior to the containment, in cooperation with shut-off valves, enable the vessel to be isolated and the system safely taken off-line. Normally-closed orifices throughout the containment and chamber enable decontamination of interior surfaces when necessary.
Chastagner, Philippe (3134 Natalie Cir., Augusta, GA 30909-2748)
Static conversion systems. [for space power reactors
Historically, all space power systems that have actually flown in space have relied on static energy conversion technology. Thus, static conversion is being considered for space nuclear power systems as well. There are four potential static conversion technologies which should be considered. These include: the alkali metal thermoelectric converter (AMTEC), the thermionic converter, the thermoelectric converter, and the thermophotovoltaic converter (TPV). These four conversion technologies will be described in brief detail along with their current status and development needs. In addition, the systems implications of using each of these conversion technologies with a space nuclear reactor power system will be evaluated and some comparisons made.
Ewell, R.; Mondt, J.
Removal of residual dissolved methane gas in an upflow anaerobic sludge blanket reactor treating low-strength wastewater at low temperature with degassing membrane.
In this study, we investigated the efficiency of dissolved methane (D-CH(4)) collection by degasification from the effluent of a bench-scale upflow anaerobic sludge blanket (UASB) reactor treating synthetic wastewater. A hollow-fiber degassing membrane module was used for degasification. This module was connected to the liquid outlet of the UASB reactor. After chemical oxygen demand (COD) removal efficiency of the UASB reactor became stable, D-CH(4) discharged from the UASB reactor was collected. Under 35 ░C and a hydraulic retention time (HRT) of 10 h, average D-CH(4) concentration could be reduced from 63 mg COD L(-1) to 15 mg COD L(-1); this, in turn, resulted in an increase in total methane (CH(4)) recovery efficiency from 89% to 97%. Furthermore, we investigated the effects of temperature and HRT of the UASB reactor on degasification efficiency. Average D-CH(4) concentration was as high as 104 mg COD L(-1) at 15 ░C because of the higher solubility of CH(4) gas in liquid; the average D-CH(4) concentration was reduced to 14 mg COD L(-1) by degasification. Accordingly, total CH(4) recovery efficiency increased from 71% to 97% at 15 ░C as a result of degasification. Moreover, degasification tended to cause an increase in particulate COD removal efficiency. The UASB reactor was operated at the same COD loading rate, but different wastewater feed rates and HRTs. Although average D-CH(4) concentration in the UASB reactor was almost unchanged (ca. 70 mg COD L(-1)) regardless of the HRT value, the CH(4) discharge rate from the UASB reactor increased because of an increase in the wastewater feed rate. Because the D-CH(4) concentration could be reduced down to 12 ▒ 1 mg COD L(-1) by degasification at an HRT of 6.7 h, the CH(4) recovery rate was 1.5 times higher under degasification than under normal operation. PMID:21550096
Bandara, Wasala M K R T W; Satoh, Hisashi; Sasakawa, Manabu; Nakahara, Yoshihito; Takahashi, Masahiro; Okabe, Satoshi
Staged membrane oxidation reactor system
Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.
Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh
Microchannel Reactor System for Catalytic Hydrogenation
We successfully demonstrated a novel process intensification concept enabled by the development of microchannel reactors, for energy efficient catalytic hydrogenation reactions at moderate temperature, and pressure, and low solvent levels. We designed, fabricated, evaluated, and optimized a laboratory-scale microchannel reactor system for hydrogenation of onitroanisole and a proprietary BMS molecule. In the second phase of the program, as a prelude to full-scale commercialization, we designed and developed a fully-automated skid-mounted multichannel microreactor pilot plant system for multiphase reactions. The system is capable of processing 1 ¢ 10 kg/h of liquid substrate, and an industrially relevant immiscible liquid-liquid was successfully demonstrated on the system. Our microreactor-based pilot plant is one-of-akind. We anticipate that this process intensification concept, if successfully demonstrated, will provide a paradigm-changing basis for replacing existing energy inefficient, cost ineffective, environmentally detrimental slurry semi-batch reactor-based manufacturing practiced in the pharmaceutical and fine chemicals industries.
Adeniyi Lawal; Woo Lee; Ron Besser; Donald Kientzler; Luke Achenie
Plasma generators, reactor systems and related methods
A plasma generator, reactor and associated systems and methods are provided in accordance with the present invention. A plasma reactor may include multiple sections or modules which are removably coupled together to form a chamber. Associated with each section is an electrode set including three electrodes with each electrode being coupled to a single phase of a three-phase alternating current (AC) power supply. The electrodes are disposed about a longitudinal centerline of the chamber and are arranged to provide and extended arc and generate an extended body of plasma. The electrodes are displaceable relative to the longitudinal centerline of the chamber. A control system may be utilized so as to automatically displace the electrodes and define an electrode gap responsive to measure voltage or current levels of the associated power supply.
Kong, Peter C. (Idaho Falls, ID); Pink, Robert J. (Pocatello, ID); Lee, James E. (Idaho Falls, ID)
System for chemical decontamination of nuclear reactor primary systems
This patent describes a method of chemically decontaminating a nuclear reactor primary system, having a residual heat removal system with one or more residual heat removal heat exchangers, each having an upstream and a downstream side, at or above ambient pressure. It comprises: injecting decontamination chemicals using an injection means; circulating the injected decontamination chemicals throughout the primary system; directing
J. S. Schlonski; M. F. McGiure; G. J. Corpora
Reactor component inventory system at FFTF
A reliable inventory control system was developed at the Fast Flux Test Facility (FFTF) to keep track of the occupancy of 900 refueling facility locations, to compile historical data on the movement of each reactor assembly, and to simulate assembly moves. The simulate capability is valuable because it allows verification of documents before they are issued for use in the plant, and eliminates the possibility of planning illegal or impossible moves. The system is installed on a UNIVAC 1100 computer and is maintained using a data base management system by Sperry Univac called MAPPER.
Ordonez, C.R.; Redekopp, R.D.; Reed, E.A.
Power conditioning for space nuclear reactor systems
This paper addresses the power conditioning subsystem for both Stirling and Brayton conversion of space nuclear reactor systems. Included are the requirements summary, trade results related to subsystem implementation, subsystem description, voltage level versus weight, efficiency and operational integrity, components selection, and shielding considerations. The discussion is supported by pertinent circuit and block diagrams. Summary conclusions and recommendations derived from the above studies are included.
Berman, Baruch
Fate of coliforms and pathogenic parasite in four full-scale sewage treatment systems in India.
The occurrence and removal of fecal indicators (total coliforms (TC), fecal coliforms (FC), fecal streptococci (FS)) and pathogens (helminthes eggs) were studied in various municipal wastewater treatment processes (UASB + FPU, ASP, EA, WSP). The reductions in TC and FC concentrations were usually between 2.0 and 2.5 log units in up-flow anaerobic sludge blanket reactor incorporated with final polishing unit (UASB + FPU). Almost similar reduction was observed in activated sludge process system (ASP) and waste stabilization ponds system (WSP), while it was log 3.0 in extended aeration system (EA). UASB + FPU and WSP systems were observed more efficient to reduce helminthes eggs at almost 100%, whereas only 97% removal was observed in case of ASP and EA system. In addition to monitoring of indicator organisms, turbidity, suspended solids (SS), and biochemical oxygen demand (BOD) were used as indirect measure of the potential presence of microorganisms. Interrelationship of BOD, SS, and turbidity with fecal indicator bacteria concentration in influent and effluent manifest that improvement of the microbiological quality of wastewater is strongly linked to the removal of BOD and SS. PMID:21136285
Tyagi, Vinay Kumar; Sahoo, B K; Khursheed, Anwar; Kazmi, A A; Ahmad, Z; Chopra, A K
A study of two-stage anaerobic digestion of solid potato waste using reactors under mesophilic and thermophilic conditions.
A two-stage anaerobic digestion process operated under mesophilic and thermophilic conditions was investigated for the treatment of solid potato waste to determine optimal methane yield, efficiency of operation and process stability. A solid-bed reactor was used for hydrolysis/acidification stage while an upflow anaerobic sludge blanket (UASB) reactor was used in the second stage, for methanogenesis. Three sets of conditions were investigated: (1) mesophilic + mesophilic, (II) mesophilic + thermophilic and (III) thermophilic + thermophilic in the hydrolysis/acidification and methanogenesis reactors, respectively. The methane yield was higher under mesophilic conditions (0.49 l CH4 g COD(-1)degraded) than thermophilic conditions (0.41 l CH4 g COD(-1)degraded) with reference to the methanogenic reactors. (COD)--chemical oxygen demand. However, the digestion period was shorter in systems II and III than in system I. Also, in system III the UASB reactor (thermophilic conditions) could handle a higher organic loading rate (OLR) (36 g COD 1(-1)d(-1)) than in system I (11 g COD 1(-1)d(-1)) (mesophilic conditions) with stable operation. Higher OLRs in the methanogenic reactors resulted in reactor failure due to increasing total volatile fatty acid levels. In all systems, the concentration of propionate was one of the highest, higher than acetic acid, among the volatile fatty acids in the effluent. The results show the feasibility of using a two-stage system to treat solid potato waste under both mesophilic and thermophilic conditions. If the aim is to treat solid potato waste completely within a short period of time thermophilic conditions are to be preferred, but to obtain higher methane yield mesophilic conditions are preferable and therefore there is a need to balance methane yield and complete digestion period when dealing with large quantities of solid potato waste. PMID:18290530
Parawira, W; Murto, M; Read, J S; Mattiasson, B
Development of a system model for advanced small modular reactors.
This report describes a system model that can be used to analyze three advance small modular reactor (SMR) designs through their lifetime. Neutronics of these reactor designs were evaluated using Monte Carlo N-Particle eXtended (MCNPX/6). The system models were developed in Matlab and Simulink. A major thrust of this research was the initial scoping analysis of Sandia's concept of a long-life fast reactor (LLFR). The inherent characteristic of this conceptual design is to minimize the change in reactivity over the lifetime of the reactor. This allows the reactor to operate substantially longer at full power than traditional light water reactors (LWRs) or other SMR designs (e.g. high temperature gas reactor (HTGR)). The system model has subroutines for lifetime reactor feedback and operation calculations, thermal hydraulic effects, load demand changes and a simplified SCO2 Brayton cycle for power conversion.
Lewis, Tom Goslee,; Holschuh, Thomas Vernon,
Treatment of textile dyes in two-phase and single-phase anaerobic bio-treatment systems.
This research integrates two different concepts of anaerobic biotechnology- two-phase anaerobic treatment and anaerobic granular sludge bed technology, in treatment of colored wastewaters from textile industries. Four anaerobic reactors based on upflow anaerobic sludge blanket (UASB) technology were used as acid reactors and an expanded granular sludge bed (EGSB) reactor was used as a methane reactor. A conventional single-phase anaerobic reactor, working on EGSB technology was run in parallel to compare the performances of the two systems. Reactors were operated at different hydraulic retention times. The results from the study, which span over a period of 400 days, indicated that the two-phase system produces a higher quality of effluent in terms of color, COD and suspended solids than single-phase anaerobic treatment when operated under similar conditions. Alkalinity requirement of two-phase system was also observed to be lower than that of single-phase system which is important regarding design consideration. PMID:18413946
Bhattacharyya, D; Singh, K S
Acetate conversion in anaerobic biogas reactors: traditional and molecular tools for studying this important group of anaerobic microorganisms.
Different methods were applied to study the role of aceticlastic methanogens in biogas reactors treating solid waste and wastewater. We used traditional microbiological methods, immunological and 16S rRNA ribosomal probes for detection of the methanogens. Using this approach we identified the methanogenic spp. and their activity. In biofilm systems, such as the UASB reactors the presence of the two aceticlastic methanogens could be correlated to the difference in the kinetic properties of the two species. In biogas reactors treating solid wastes, such as manure or mixture of manure and organic industrial waste, only Methanosarcina spp. were identified. Methanosarcina spp. isolated from different plants had different kinetics depending on their origin. Relating the reactor performance data to measurement of the activity by conventional microbiological methods gave a good indication of the microbial status of specific trophic groups. 16S rRNA probing confirmed these observations and gave a more detailed picture of the microbial groups present. PMID:11587438
Schmidt, J E; Mladenovska, Z; Lange, M; Ahring, B K
Integrated systems analysis of the PIUS reactor
Results are presented of a systems failure analysis of the PIUS plant systems that are used during normal reactor operation and postulated accidents. This study was performed to provide the NRC with an understanding of the behavior of the plant. The study applied two diverse failure identification methods, Failure Modes Effects & Criticality Analysis (FMECA) and Hazards & Operability (HAZOP) to the plant systems, supported by several deterministic analyses. Conventional PRA methods were also used along with a scheme for classifying events by initiator frequency and combinations of failures. Principal results of this study are: (a) an extensive listing of potential event sequences, grouped in categories that can be used by the NRC, (b) identification of support systems that are important to safety, and (c) identification of key operator actions.
Fullwood, F.; Kroeger, P.; Higgins, J. [Brookhaven National Lab., Upton, NY (United States)] [and others
Microrecirculation reactor system for characterization of immobilized enzymes
A differential microrecirculation reactor was developed for kinetic analysis of both soluble and immobilized enzymes. The reactor system was easily fabricated within the laboratory from readily available materials. The disposable, small reactors allowed for in situ weight determination of the enzyme beads. Routinely, only a 1 ml liquid volume of substrate was used for each kinetic assay. The reactor system was also used for determination of partition coefficients. Both uses of the reactor system required only 5-10 minutes for completion of a given determination.
Taylor, J.B.; Swaisgood, H.E.
Nuclear reactor fuel rod attachment system
A reusable system is described for removably attaching a nuclear reactor fuel rod to a support member. A locking cap is secured to the fuel rod and a locking strip is fastened to the support member. The locking cap has two opposing fingers shaped to form a socket having a body portion. The locking strip has an extension shaped to rigidly attach to the socket's body portion. The locking cap's fingers are resiliently deflectable. For attachment, the locking cap is longitudinally pushed onto the locking strip causing the extension to temporarily deflect open the fingers to engage the socket's body portion. For removal, the process is reversed.
Not Available
Method of vacuum degassing and refilling a reactor coolant system
A method is described for vacuum degassing a pressurized water reactor coolant system (RCS) having reactor coolant containing radiogas and nonradiogas and a reactor pressure vessel connected to at least one steam generator by a hot leg, comprising: draining down the RCS to approximately the midpoint of the hot leg; maintaining the RCS in an unvented condition during the step
J. Battaglia; R. W. Fleming
Structural materials challenges for advanced reactor systems
Key technologies for advanced nuclear systems encompass high temperature structural materials, fast neutron resistant core materials, and specific reactor and power conversion technologies (intermediate heat exchanger, turbo-machinery, high temperature electrolytic or thermo-chemical water splitting processes, etc.). The main requirements for the materials to be used in these reactor systems are dimensional stability under irradiation, whether under stress (irradiation creep or relaxation) or without stress (swelling, growth), an acceptable evolution under ageing of the mechanical properties (tensile strength, ductility, creep resistance, fracture toughness, resilience) and a good behavior in corrosive environments (reactor coolant or process fluid). Other criteria for the materials are their cost to fabricate and to assemble, and their composition could be optimized in order for instance to present low-activation (or rapid desactivation) features which facilitate maintenance and disposal. These requirements have to be met under normal operating conditions, as well as in incidental and accidental conditions. These challenging requirements imply that in most cases, the use of conventional nuclear materials is excluded, even after optimization and a new range of materials has to be developed and qualified for nuclear use. This paper gives a brief overview of various materials that are essential to establish advanced systems feasibility and performance for in pile and out of pile applications, such as ferritic/martensitic steels (9-12% Cr), nickel based alloys (Haynes 230, Inconel 617, etc.), oxide dispersion strengthened ferritic/martensitic steels, and ceramics (SiC, TiC, etc.). This article gives also an insight into the various natures of R&D needed on advanced materials, including fundamental research to investigate basic physical and chemical phenomena occurring in normal and accidental operating conditions, lab-scale tests to characterize candidate materials mechanical properties and corrosion resistance, as well as component mock-up tests on technology loops to validate potential applications while accounting for mechanical design rules and manufacturing processes. The selection, assessment and validation of materials necessitate a large number of experiments, involving rare and expensive facilities such as research reactors, hot laboratories or corrosion loops. The modelling and the codification of the behaviour of materials will always involve the use of such technological experiments, but it is of utmost importance to develop also a predictive material science. Finally, the paper stresses the benefit of prospects of multilateral collaboration to join skills and share efforts of R&D to achieve in the nuclear field breakthroughs on materials that have already been achieved over the past decades in other industry sectors (aeronautics, metallurgy, chemistry, etc.).
Yvon, P.; Carrķ, F.
Nuclear reactor with passive safety system
This patent describes a pressurized nuclear water reactor that has a substantially cylindrical flow liner with a cylindrical wall section and bottom and an open top. A barrel forms a riser chamber that contains the core in the flow liner. A pressure vessel contains the cylindrical flow liner to form a second annular chamber therebetween that contains a supplementary liquid coolant, with insulation means to provide a major portion of the supplementary liquid coolant at a first temperature and a minor portion thereof at a second higher temperature. Upon depressurization in the vessel, fluid communication means enable injection of supplementary liquid coolant from the second annular chamber into the core upon flashing of a minor portion to vapor. A further pool of water outside the pressure vessel, and insulation on the wall, maintain the desired temperature in the supplementary liquid coolant supply. Injection or removal of borated solution, as a chemistry control solution, into or from the supplementary liquid coolant is provided. A passive safety system incorporates the reactor with means for circulating water solely by natural convection from the hog leg to the cold leg of the primary coolant system and has heat exchange means associated therewith.
Tower, S.N.; Schulz, T.L.
Fuel Systems for Compact Fast Space Reactors.
About 200 refractory metal clad ceramic fuel pins have been irradiated in thermal reactors under the 1200 K to 1550 K cladding temperature conditions of primary relevance to space reactors. This paper reviews performance with respect to fissile atom densi...
C. M. Cox D. S. Dutt R. A. Karnesky
Proceedings of a Symposium on Advanced Compact Reactor Systems
Reactor system technologies suitable for a variety of aerospace and terrestrial applications are considered. Technologies, safety and regulatory considerations, potential applications, and research and development opportunities are covered.
Essential metal depletion in an anaerobic reactor.
The effect of the absence of trace elements on the conversion of a mixture of volatile fatty acids by a distillery anaerobic granular sludge was investigated. Two UASB reactors were operated under identical operational conditions except for the influent trace metal concentrations, during 140 days. Experiments were carried out in three periods, where different organic loading rates (OLR) were applied to the reactors. The total trace metal concentration steadily decreased at a rate of 48 microg metal/g TS.d in the deprived reactor (down to 35% of their initial value). In contrast, trace metals accumulated in granules present in the control reactor. At the end of the experiment, the COD removal efficiencies were 99% and 77% for the control and deprived reactors, respectively, due to the lack of propionate conversion. Cobalt sorption experiments were carried out in order to study its speciation, and its effects on the speciation of other metals as well. A paper mill wastewater treating granular sludge was also included in the study as a comparison. Results obtained showed that the principal metal forms normally associated with any sludge are a function of each soluble metal concentration in the system, and the characteristics of the particular sludge. PMID:14640193
Osuna, M B; Iza, J; Zandvoort, M; Lens, P N L
REACTOR - a Concept for establishing a System-of-Systems
Haener, Rainer; Hammitzsch, Martin; Wõchter, Joachim
Application of Stable Adaptive Schemes to Nuclear Reactor Systems, (II)
The parameter identification and adaptive control schemes applied in a previous study to a nonlinear point reactor are extended to the case of a loosely-coupled-core reactor with internal feedbacks, constituting a nonlinear overall system. Both schemes are shown to be stable, with the system newly represented on the pattern of the Model Reference Adaptive System (MRAS) with use made of
Toshio FUKUDA
Space reactor power systems with no single point failures
Nuclear reactor power systems could revolutionize space exploration and support human outpost on the moon and Mars. This paper reviews various energy conversion technologies for use in space reactor power systems and provides estimates of the system's net efficiency and specific power, and the specific area of the radiator. The suitable combinations of the energy conversion technologies and the nuclear
Mohamed S. El-Genk
Improved Dechlorinating Performance of Upflow Anaerobic Sludge Blanket Reactors by Incorporation of Dehalospirillum multivorans into Granular Sludge
Dechlorination of tetrachloroethene, also known as perchloroethylene (PCE), was investigated in an upflow anaerobic sludge blanket (UASB) reactor after incorporation of the strictly anaerobic, reductively dechlori- nating bacterium Dehalospirillum multivorans into granular sludge. This reactor was compared to the reference 1 (R1) reactor, where the granules were autoclaved to remove all dechlorinating abilities before inoculation, and to the reference 2
Experimental Evaluation of an Expert System for Nuclear Reactor Operators.
The United States Nuclear Regulatory Commission (USNRC) is supporting a program for the experimental evaluation of an expert system for nuclear reactor operators. A prototype expert system, called the Response Tree System, has been developed and implement...
W. R. Nelson
Fluid sampling system for a nuclear reactor
A system of extracting fluid samples, either liquid or gas, from the interior of a nuclear reactor containment utilizes a jet pump. To extract the sample fluid, a nonradioactive motive fluid is forced through the inlet and discharge ports of a jet pump located outside the containment, creating a suction that draws the sample fluid from the containment through a sample conduit connected to the pump suction port. The mixture of motive fluid and sample fluid is discharged through a return conduit to the interior of the containment. The jet pump and means for removing a portion of the sample fluid from the sample conduit can be located in a shielded sample grab station located next to the containment. A non-nuclear grade active pump can be located outside the grab sampling station and the containment to pump the nonradioactive motive fluid through the jet pump. 1 fig.
Lau, L.K.; Alper, N.I.
A reusable system for removably attaching a nuclear reactor fuel rod (12) to a support member (14). A locking cap (22) is secured to the fuel rod (12) and a locking strip (24) is fastened to the support member (14). The locking cap (22) has two opposing fingers (24a and 24b) shaped to form a socket having a body portion (26). The locking strip has an extension (36) shaped to rigidly attach to the socket's body portion (26). The locking cap's fingers are resiliently deflectable. For attachment, the locking cap (22) is longitudinally pushed onto the locking strip (24) causing the extension (36) to temporarily deflect open the fingers (24a and 24b) to engage the socket's body portion (26). For removal, the process is reversed.
Christiansen, David W. (Kennewick, WA)
A system of extracting fluid samples, either liquid or gas, from the interior of a nuclear reactor containment utilizes a jet pump. To extract the sample fluid, a nonradioactive motive fluid is forced through the inlet and discharge ports of a jet pump located outside the containment, creating a suction that draws the sample fluid from the containment through a sample conduit connected to the pump suction port. The mixture of motive fluid and sample fluid is discharged through a return conduit to the interior of the containment. The jet pump and means for removing a portion of the sample fluid from the sample conduit can be located in a shielded sample grab station located next to the containment. A non-nuclear grade active pump can be located outside the grab sampling station and the containment to pump the nonradioactive motive fluid through the jet pump.
Lau, Louis K. (Monroeville, PA); Alper, Naum I. (Monroeville, PA)
MAPLE-X10 reactor digital control system
The MAPLE-X10 reactor, currently under construction at the Chalk River Laboratories of Atomic Energy of Canada Limited, is a 10-MW(thermal), pool-type light water reactor. It will be used for radioisotope production and silicon neutron transmutation doping. The reactor is controlled by a digital control system (DCS) and protected against abnormal process events by two independent safety systems. The application of
M. T. DeVerno; H. W. Hinds
Technology gap analysis on sodium-cooled reactor fuel handling system supporting advanced burner reactor development
The goals of the Global Nuclear Energy Partnership (GNEP) are to expand the use of nuclear energy to meet increasing global energy demand in an environmentally sustainable manner, to address nuclear waste management issues without making separated plutonium, and to address nonproliferation concerns. The advanced burner reactor (ABR) is a fast reactor concept which supports the GNEP fuel cycle system.
Y. Chikazawa; M. Farmer; C. Grandy
The Rockwell SR-100G reactor turboelectric space power system
During FY 1982 and 1983, Rockwell International performed system and subsystem studies for space reactor power systems. These studies drew on the expertise gained from the design and flight of the SNAP-10A space nuclear reactor system. These studies, performed for the SP-100 Program, culminated in the selection of a reactor-turboelectric (gas Brayton) system for the SP-100 application; this system is called the SR-100G. This paper describes the features of the system and provides references where more detailed information can be obtained.
Anderson, R. V.
Expert Systems for Fault Diagnosis in Nuclear Reactor Control.
An expert system for accident analysis and fault diagnosis for the Loss Of Fluid Test (LOFT) reactor, a small scale pressurized water reactor, was developed for a personal computer. The knowledge of the system is presented using a production rule approach...
N. A. Jalel H. Nicholson
Modeling delayed neutron monitoring systems for fast breeder reactors
The purpose of the present work was to develop a general expression relating the count rate of a delayed neutron monitoring system to the introduction rate of fission fragments into the sodium coolant of a fast breeder reactor. Most fast breeder reactors include a system for detecting the presence of breached fuel that permits contact between the sodium coolant and
W. L. Bunch; E. L. Tang
Small reactor power systems for manned planetary surface bases
A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a
Harvey S. Bloomfield
Liquid metal cooled nuclear reactors with passive cooling system
A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of cooling medium flow circuits which cooperate to remove and carry heat away from the fuel core upon loss of the normal cooling flow circuit to areas external thereto.
Hunsbedt, Anstein (Los Gatos, CA); Fanning, Alan W. (San Jose, CA)
Exhaust system with emissions storage device and plasma reactor
An exhaust system for a combustion system, comprising a storage device for collecting NO.sub.x, hydrocarbon, or particulate emissions, or mixture of these emissions, and a plasma reactor for destroying the collected emissions is described. After the emission is collected in by the storage device for a period of time, the emission is then destroyed in a non-thermal plasma generated by the plasma reactor. With respect to the direction of flow of the exhaust stream, the storage device must be located before the terminus of the plasma reactor, and it may be located wholly before, overlap with, or be contained within the plasma reactor.
Hoard, John W. (Livonia, MI)
Prism reactor system design and analysis of postulated unscrammed events
Key safety characteristics of the PRISM reactor system include the passive reactor shutdown characteristic and the passive shutdown heat removal system, RVACS. While these characteristics are simple in principle, the physical processes are fairly complex, particularly for the passive reactor shutdown. It has been possible to adapt independent safety analysis codes originally developed for the Clinch River Breeder Reactor review, although some limitations remain. In this paper, the analyses of postulated unscrammed events are discussed, along with limitations in the predictive capabilities and plans to correct the limitations in the near future. 6 refs., 4 figs.
Van Tuyle, G.J.; Slovik, G.C.
PRISM reactor system design and analysis of postulated unscrammed events
Key safety characteristics of the PRISM reactor system include the passive reactor shutdown characteristics and the passive shutdown heat removal system, RVACS. While these characteristics are simple in principle, the physical processes are fairly complex, particularly for the passive reactor shutdown. It has been possible to adapt independent safety analysis codes originally developed for the Clinch River Breeder Reactor review, although some limitations remain. In this paper, the analyses of postulated unscrammed events are discussed, along with limitations in the predictive capabilities and plans to correct the limitations in the near future. 6 refs., 4 figs.
Van Tuyle, G.J.; Slovik, G.C. (Brookhaven National Lab., Upton, NY (United States)); Rosztoczy, Z.; Lane, J. (Nuclear Regulatory Commission, Washington, DC (United States))
System pressure effect on the nuclear reactor limiting criterion
The acceptable operating limits of a nuclear reactor are set to prevent fuel cladding damage. Critical heat flux (CHF) is the limiting criterion for high-pressure systems such as boiling water reactors (BWRs) (6.9 MPa) and pressurized water reactors (PWRs) (13.8 MPa). However, the onset of flow instability (OFI) is the limiting criterion of low-pressure systems such as the Savannah River Site (SRS) production reactors (0.2 MPa). The physical basis of this difference is discussed in this paper.
Kuofu Chen (Westinghouse Savannah River Co., Aiken, SC (United States))
The feasibility of the upflow anaerobic sludge bed (UASB) process for the treatment of potato starch wastewater at low ambient temperatures was demonstrated by operating two 5.65 l reactors at 14 degrees C and 20 degrees C, respectively. The organic space loading rates achieved in these laboratory-scale reactors were 3 kg COD/cubic m/day at 14 degrees C and 4-5 kg COD/cubic m/day at 20 degrees C. The corresponding sludge loading rates were 0.12 kg COD/kg VSS/day at 14 degrees C and 0.16-0.18 kg COD/kg VSS/day at 20 degrees C. These findings are of considerable practical importance because application of anaerobic treatment at low ambient temperatures will lead to considerable savings in energy needed for operating the process. As compared with various other anaerobic wastewater treatment processes, a granular sludge upflow process represents one of the best options developed so far. Although the overall sludge yield under psychrophilic conditions is slightly higher than under optimal mesophilic conditions, this doesn't seriously hamper the operation of the process. The extra sludge yield, due to accumulation of slowly hydrolyzing substrate ingredients, was 4.75% of the COD input at 14 degrees C and 1.22% of the COD input at 20 degrees C. 26 references.
Koster, I.W.; Lettinga, G.
Design of a 25-kWe Surface Reactor System Based on SNAP Reactor Technologies
A Hastelloy-X clad, sodium-potassium (NaK-78) cooled, moderated spectrum reactor using uranium zirconium hydride (UZrH) fuel based on the SNAP program reactors is a promising design for use in surface power systems. This paper presents a 98 kWth reactor for a power system the uses multiple Stirling engines to produce 25 kWe-net for 5 years. The design utilizes a pin type geometry containing UZrHx fuel clad with Hastelloy-X and NaK-78 flowing around the pins as coolant. A compelling feature of this design is its use of 49.9% enriched U, allowing it to be classified as a category III-D attractiveness and reducing facility costs relative to highly-enriched space reactor concepts. Presented below are both the design and an analysis of this reactor's criticality under various safety and operations scenarios.
Dixon, David D.; Hiatt, Matthew T.; Poston, David I.; Kapernick, Richard J.
Development of Reactor Core Surveillance System for PARR,
A computer based surveillance system has been developed at PARR for an early detection and identification of any core abnormality. The system acquires various plant signals monitoring the reactor core condition and performs the frequency analysis of the f...
S. A. Ansari S. K. Ayazuddin
High Temperature Gas Reactor and Energy Pipeline System.
A study was made of the following aspects of the High Temperature Gas Reactor (HTGR) Closed Loop Chemical Energy Pipeline (CEP) concept: pipeline transmission and storage system design, pipeline and storage system cost, methane reformer interface, and sys...
E. Daniels C. Blazek D. C. Allen G. R. Pflasterer
The MAPLE-X10 reactor, currently under construction at the Chalk River Laboratories of Atomic Energy of Canada Limited, is a 10-MW(thermal), pool-type light water reactor. It will be used for radioisotope production and silicon neutron transmutation doping. The reactor is controlled by a digital control system (DCS) and protected against abnormal process events by two independent safety systems. The application of digital instrument and control systems on a research reactor provides a number of advantages to the operator. Among these are logging of parameters, automatic tests of key circuits and measurement channels, human factor operator interface, and rapid detection of different types of faults. A common factor of all these advantages is that the operator can devote more time to the operation of the reactor and its experiments and less time to the mechanics of maintenance and verifying that the system is in an operable condition.
DeVerno, M.T.; Hinds, H.W. (Atomic Energy of Canada Ltd., Chalk River Ontario (Canada))
Method for preventing oxygen corrosion in a boiling water nuclear reactor and improved boiling water reactor system
This patent describes a method for prevention of corrosion, due to oxygen activity, in a boiling water nuclear reactor system having a main feedwater recirculation loop comprising a reactor vessel with a reactor core and with a steam off-take line and a condensate return line in flow communication with the vessel for recirculating feedwater between the reactor and a steam
78 FR 28896 - Design Limits and Loading Combinations for Metal Primary Reactor Containment System Components
Federal Register 2010, 2011, 2012, 2013
...Limits and Loading Combinations for Metal Primary Reactor Containment System Components...Limits and Loading Combinations for Metal Primary Reactor Containment System Components...limits and loading combinations for metal primary reactor containment system...
Autotrophic ammonium removal from reject water: partial nitrification and anammox in one?reactor versus two?reactor systems
Removal of total nitrogen from anaerobically digested sludge reject water by a fully autotrophic process in either one? or two?reactor systems was compared. Autotrophic nitrogen removal is currently most often applied in the one?reactor system primarily in the DEMON configuration. The two?reactor systems had a similar nitrogen removal rate to the one?reactor systems. It was evident that the limiting step
L. W. Jaroszynski; J. A. Oleszkiewicz
Treatment of winery effluent with upflow anaerobic sludge blanket (UASB) ¢ granular sludges enriched with Enterobacter sakazakii
Three upflow anaerobic sludge blankets (UASBs) were evaluated for the treatment of winery wastewater: the first was seeded with granular sludge enriched with Enterobacter sakazakii and reached a 90% COD removal within 17Ād at hydraulic retention time of 24Āh; the second was seeded with brewery granules and achieved 85% COD removal within 50Ād, the third was seeded with just sludge
M. Keyser; R. C. Witthuhn; L.-C. Ronquest; T. J. Britz
Catalytic reactor system for the tritium emissions reduction facility
Two platinum catalyst reactor subsystems have been built for the new Tritium Emissions Reduction Facility (TERF) at Mound. The two parallel subsystems each consist of three major components: a passive conservation heat exchanger, an electric preheater, and a catalytic reactor. All subsystem components and interconnecting piping are fabricated from Inconel 625 for high temperature strength and corrosion resistance. System connections
A systems analysis of the ARIES tokamak reactors
The multi-institutional ARIES study has completed a series of cost-of-electricity optimized conceptual designs of commercial tokamak fusion reactors that vary the assumed advances in technology and physics. A comparison of these designs indicates the cost benefit of various design options. A parametric systems analysis suggests a possible means to obtain a marginally competitive fusion reactor.
Bathke, C.G.
Extreme thermophilic biohydrogen production from wheat straw hydrolysate using mixed culture fermentation: effect of reactor configuration.
Hydrogen production from hemicellulose-rich wheat straw hydrolysate was investigated in continuously-stirred tank reactor (CSTR), up-flow anaerobic sludge bed (UASB) reactor, and anaerobic filter (AF) reactor. The CSTR was operated at an hydraulic retention time (HRT) of 3 days, and the UASB and AF reactors were operated at 1 day HRT, using mixed extreme thermophiles at 70 ░C. The highest hydrogen production yield of 212.0▒6.6 mL-H?/g-sugars, corresponding to a hydrogen production rate of 821.4▒25.5 mL-H?/dL was achieved with the UASB reactor. Lowering the HRT to 2.5 days caused cell mass washout in the CSTR, while the UASB and AF reactors gave fluctuating and reducing hydrogen production at a 0.5-day HRT. The original rate and yield were recovered when the HRT was increased back to 1 day. These results demonstrate that reactor configuration is an important factor for enhancing and stabilizing H? production. PMID:20554199
Kongjan, Prawit; Angelidaki, Irini
A fast shutdown system for SRS (Savannah River Site) reactors
Power has been sharply reduced at Savannah River Site (SRS) reactors in large part to ensure that no bulk boiling occurs during hypothesized loss of coolant accidents. A fast shutdown system is essential to regain much of this lost power. Computations and experiments indicate that a He-3 injection system will serve this function. Instrumented tests of a full system are planned for early 1991 for one of the SRS reactors. 4 refs., 7 figs., 1 tab.
Baumann, N.P.
SP-100 program: Space reactor system and subsystem investigations
For a space reactor power system, a comprehensive safety program will be required to assure that no undue risk is present. The nuclear safety review/approval process that is required for a space reactor system is summarized. The documentation requirements are presented along with a summary of the required contents of key documents. Finally, the aerospace safety program conducted for the SNAP-10A reactor system is summarized. The results of this program are presented to show the type of program that is expected and to provide information that could be usable in future programs.
Harty, R. B.
SP-100 Program: space reactor system and subsystem investigations
For a space reactor power system, a comprehensive safety program will be required to assure that no undue risk is present. This report summarizes the nuclear safety review/approval process that will be required for a space reactor system. The documentation requirements are presented along with a summary of the required contents of key documents. Finally, the aerospace safety program conducted for the SNAP-10A reactor system is summarized. The results of this program are presented to show the type of program that can be expected and to provide information that could be usable in future programs.
Harty, R.B.
Gas-cooled reactor for space power systems
Reactor characteristics based on extensive development work on the 500-MWt reactor for the Pluto nuclear ramjet are described for space power systems useful in the range of 2 to 20 MWe for operating times of 1 y. The modest pressure drop through the prismatic ceramic core is supported at the outlet end by a ceramic dome which also serves as a neutron reflector. Three core materials are considered which are useful at temperatures up to about 2000 K. Most of the calculations are based on a beryllium oxide with uranium dioxide core. Reactor control is accomplished by use of a burnable poison, a variable-leakage reflector, and internal control rods. Reactivity swings of 20% are obtained with a dozen internal boron-10 rods for the size cores studied. Criticality calculations were performed using the ALICE Monte Carlo code. The inherent high-temperature capability of the reactor design removes the reactor as a limiting condition on system performance. The low fuel inventories required, particularly for beryllium oxide reactors, make space power systems based on gas-cooled near-thermal reactors a lesser safeguard risk than those based on fast reactors.
Walter, C.E.; Pearson, J.S.
Metrology/viewing system for next generation fusion reactors
Next generation fusion reactors require accurate measuring systems to verify sub-millimeter alignment of plasma-facing components in the reactor vessel. A metrology system capable of achieving such accuracy must be compatible with the vessel environment of high gamma radiation, high vacuum, elevated temperature, and magnetic field. This environment requires that the system must be remotely deployed. A coherent, frequency modulated laser radar system is being integrated with a remotely operated deployment system to meet these requirements. The metrology/viewing system consists of a compact laser transceiver optics module which is linked through fiber optics to the laser source and imaging units that are located outside of the harsh environment. The deployment mechanism is a telescopic-mast positioning system. This paper identifies the requirements for the International Thermonuclear Experimental Reactor metrology and viewing system, and describes a remotely operated precision ranging and surface mapping system.
Spampinato, P.T.; Barry, R.E.; Chesser, J.B.; Menon, M.M. [Oak Ridge National Lab., TN (United States); Dagher, M.A. [Boeing Rocketdyne Div., Canoga Park, CA (United States)
Clean-up sub-system for chemical decontamination of nuclear reactor primary systems
This patent describes a chemical decontamination clean-up system for use on-line in a nuclear reactor primary system. It comprises: a back-flushable filter; means within the nuclear reactor primary system for pumping primary system fluids from the nuclear reactor primary system downstream to the back-flushable filter and thereafter through the decontamination system; a plurality of demineralizer banks arranged in parallel, each
G. J. Corpora; J. S. Schlonski; F. I. Bauer; P. E. Miller
Microprocessor tester for the treat upgrade reactor trip system
The upgrading of the Transient Reactor Test (TREAT) Facility at ANL-Idaho has been designed to provide additional experimental capabilities for the study of core disruptive accident (CDA) phenomena. In addition, a programmable Automated Reactor Control System (ARCS) will permit high-power transients up to 11,000 MW having a controlled reactor period of from 15 to 0.1 sec. These modifications to the core neutronics will improve simulation of LMFBR accident conditions. Finally, a sophisticated, multiply-redundant safety system, the Reactor Trip System (RTS), will provide safe operation for both steady state and transient production operating modes. To insure that this complex safety system is functioning properly, a Dedicated Microprocessor Tester (DMT) has been implemented to perform a thorough checkout of the RTS prior to all TREAT operations.
Lenkszus, F.R.; Bucher, R.G.
Programmable Logic Controller and Its Application in Nuclear Reactor Systems.
The document provides recommendations to guide reviewers in the application of Programmable Logic Controllers (PLCs) to the control, monitoring and protection of nuclear reactors. Topics addressed are system-level design issues, specifically including saf...
J. Palomar R. Wyman
Steam generator recirculating system for a pressurized water nuclear reactor
This patent describes a steam generator recirculating system for the recirculation of secondary coolant, for use with the nuclear steam supply system of a pressurized water nuclear reactor plant having at least two steam generators, main feedwater lines to each steam generator and a blowdown system for each steam generator. The system comprises: a discharge line for receipt of a
R. A. Loose; J. S. Schlonski; C. C. Steinkuhler
Natural circulating passive cooling system for nuclear reactor containment structure
A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.
Gou, Perng-Fei (Saratoga, CA); Wade, Gentry E. (Saratoga, CA)
Passive cooling system for nuclear reactor containment structure
Tetrachloroethene dechlorination kinetics by Dehalospirillum multivorans immobilized in upflow anaerobic sludge blanket reactors
Tetrachloroethene (C2Cl4) dechlorination kinetics in upflow anaerobic sludge blanket (UASB) reactors was determined after introducing de novo activities into the granular sludge. These activities were introduced by immobilizing Dehalospirillum multivorans in a test reactor containing unsterile granular sludge, and in a reference reactor, R1, containing sterile granular sludge.\\u000a A second reference reactor, R2, contained only unsterile granular sludge and served
C. H÷rber; N. Christensen; E. Arvin; B. Kiµr Ahring
Anaerobic digestion Of a Petrochemical Wastewater using the UASB process
Anaerobic digestion of effluent from a petrochemical plant producing terephthalic acid has been tested using two Upflow Anaerobic\\u000a Sludge Blanket (USAB) reactors. The reactors were seeded with two different inocula: one from an anaerobic stabilization pond\\u000a receiving wasted sludge from the aerobic treatment plant of the petrochemical industry (reactor A); the other was an anaerobically\\u000a adapted activated sludge from a
J. P. Guyot; H. Macarie; A. Noyola
System aspects of a Space Nuclear Reactor Power System
Selected systems aspects of a 300 kW nuclear reactor power system for spacecraft have been studied. The approach included examination of two candidate missions and their associated spacecraft, and a number of special topics dealing with the power system design and operation. The missions considered were a reusable orbital transfer vehicle and a space-based radar. The special topics included: power system configuration and scaling, launch vehicle integration, operating altitude, orbital storage, start-up, thawing, control, load following, procedures in case of malfunction, restart, thermal and nuclear radiation to other portions of the spacecraft, thermal stresses between subsystems, boom and cable designs, vibration modes, altitude control, reliability, and survivability. Among the findings are that the stowed length of the power system is important to mission design and that orbital storage for months to years may be needed for missions involving orbital assembly. The power system design evolved during the study and has continued to evolve; the current design differs somewhat from that examined in this paper.
Jaffe, L.; Fujita, T.; Beatty, R.; Bhandari, P.; Chow, E.; Deininger, W.; Ewell, R.; Grossman, M.; Kia, T.; Nesmith, B.
Small space reactor power systems for unmanned solar system exploration missions
A preliminary feasibility study of the application of small nuclear reactor space power systems to the Mariner Mark II Cassini spacecraft/mission was conducted. The purpose of the study was to identify and assess the technology and performance issues associated with the reactor power system/spacecraft/mission integration. The Cassini mission was selected because study of the Saturn system was identified as a high priority outer planet exploration objective. Reactor power systems applied to this mission were evaluated for two different uses. First, a very small 1 kWe reactor power system was used as an RTG replacement for the nominal spacecraft mission science payload power requirements while still retaining the spacecraft's usual bipropellant chemical propulsion system. The second use of reactor power involved the additional replacement of the chemical propulsion system with a small reactor power system and an electric propulsion system. The study also provides an examination of potential applications for the additional power available for scientific data collection. The reactor power system characteristics utilized in the study were based on a parametric mass model that was developed specifically for these low power applications. The model was generated following a neutronic safety and operational feasibility assessment of six small reactor concepts solicited from U.S. industry. This assessment provided the validation of reactor safety for all mission phases and generatad the reactor mass and dimensional data needed for the system mass model.
Bloomfield, H.S.
Bloomfield, Harvey S.
Reference Reactor Module for the Affordable Fission Surface Power System
Surface fission power systems on the Moon and Mars may provide the first US application of fission reactor technology in space since 1965. The requirements of many surface power applications allow the consideration of systems with much less development risk than most other space reactor applications, because of modest power (10s of kWe) and no driving need for minimal mass (allowing temperatures <1000 K). The Affordable Fission Surface Power System (AFSPS) study was completed by NASA/DOE to determine the cost of a modest performance, low-technical risk surface power system. This paper describes the reference AFSPS reactor module concept, which is designed to provide a net power of 40 kWe for 8 years on the lunar surface; note, the system has been designed with technologies that are fully compatible with a Martian surface application. The reactor concept uses stainless-steel based, UO{sub 2}-fueled, liquid metal-cooled fission reactor coupled to free-piston Stirling converters. The reactor shielding approach utilizes both in-situ and launched shielding to keep the dose to astronauts much lower than the natural background radiation on the lunar surface. One of the important 'affordability' attributes is that the concept has been designed to minimize both the technical and programmatic safety risk.
Poston, David I.; Kapernick, Richard J.; Dixon, David D.; Amiri, Benjamin W.; Marcille, Thomas F. [Nuclear Systems Design Group, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545 (United States)
Gas-cooled reactor power systems for space
In this paper the characteristics of six designs for power levels of 2, 10, and 20 MWe for operating times of 1 and 7 y are described. The operating conditions for these arbitrary designs were chosen to minimize system specific mass. The designs are based on recent work which benefits from earlier analyses of nuclear space power systems conducted at our Laboratory. Both gas- and liquid-cooled reactors had been considered. Pitts and Walter (1970) reported on the results of a detailed study of a 10-MWe lithium-cooled reactor in a potassium Rankine system. Unpublished results (1966) of a computer analysis provide details of an argon-cooled reactor in an argon Brayton system. The gas-cooled reactor design was based on extensive development work on the 500-MWth reactor for the nuclear ramjet (Pluto) as described by Walter (1964). The designs discussed here draw heavily on the Pluto project experience, which culminated in a successful full-power ground test as reported by Reynolds (1964). At higher power levels gas-cooled reactors coupled with Brayton systems with advanced radiator designs become attractive.
Walter, C.E.
New reactor technology: safety improvements in nuclear power systems.
Almost 450 nuclear power plants are currently operating throughout the world and supplying about 17% of the world's electricity. These plants perform safely, reliably, and have no free-release of byproducts to the environment. Given the current rate of growth in electricity demand and the ever growing concerns for the environment, nuclear power can only satisfy the need for electricity and other energy-intensive products if it can demonstrate (1) enhanced safety and system reliability, (2) minimal environmental impact via sustainable system designs, and (3) competitive economics. The U.S. Department of Energy with the international community has begun research on the next generation of nuclear energy systems that can be made available to the market by 2030 or earlier, and that can offer significant advances toward these challenging goals; in particular, six candidate reactor system designs have been identified. These future nuclear power systems will require advances in materials, reactor physics, as well as thermal-hydraulics to realize their full potential. However, all of these designs must demonstrate enhanced safety above and beyond current light water reactor systems if the next generation of nuclear power plants is to grow in number far beyond the current population. This paper reviews the advanced Generation-IV reactor systems and the key safety phenomena that must be considered to guarantee that enhanced safety can be assured in future nuclear reactor systems. PMID:18049233
Corradini, M L
Computer based systems for Prototype Fast Breeder Reactor
Computer based Instrumentation & Control (I&C) systems are extensively deployed in the 500 MWe Prototype Fast Breeder Reactor (PFBR), which is under construction at Kalpakkam. They are employed in safety critical and safety related systems. The hardware and software for these systems have been designed in accordance with Atomic Energy Regulatory board (AERB) safety guides. Further, the hardware designed and
N. Sridhar; B. Krishnakumar; S. Ilango Sambasivan
This paper describes the Plant Computing Environment (PCE), a distributed computing environment supporting a high-level supervisory control and monitoring system. The goal is to coordinate plant fault detection, performance monitoring, and control system settings, so that the plant continues to meet performance specifications as plant conditions change. The study is aimed at future nuclear reactor systems. The PCE is a
James A. Mullens; Josķ March-Leuba; Richard T. Wood; Carlton R. Brittain
Deployment history and design considerations for space reactor power systems
The history of the deployment of nuclear reactors in Earth orbits is reviewed with emphases on lessons learned and the operation and safety experiences. The former Soviet Union's "BUK" power systems, with SiGe thermoelectric conversion and fast neutron energy spectrum reactors, powered a total of 31 Radar Ocean Reconnaissance Satellites (RORSATs) from 1970 to 1988 in 260 km orbit. Two of the former Soviet Union's TOPAZ reactors, with in-core thermionic conversion and epithermal neutron energy spectrum, powered two Cosmos missions launched in 1987 in ś800 km orbit. The US' SNAP-10A system, with SiGe energy conversion and a thermal neutron energy spectrum reactor, was launched in 1965 in 1300 km orbit. The three reactor systems used liquid NaK-78 coolant, stainless steel structure and highly enriched uranium fuel (90-96 wt%) and operated at a reactor exit temperature of 833-973 K. The BUK reactors used U-Mo fuel rods, TOPAZ used UO 2 fuel rods and four ZrH moderator disks, and the SNAP-10A used moderated U-ZrH fuel rods. These low power space reactor systems were designed for short missions (ś0.5 kW e and ś1 year for SNAP-10A, <3.0 kW e and <6 months for BUK, and ś5.5 kW e and up to 1 year for TOPAZ). The deactivated BUK reactors at the end of mission, which varied in duration from a few hours to ś4.5 months, were boosted into ś800 km storage orbit with a decay life of more than 600 year. The ejection of the last 16 BUK reactor fuel cores caused significant contamination of Earth orbits with NaK droplets that varied in sizes from a few microns to 5 cm. Power systems to enhance or enable future interplanetary exploration, in-situ resources utilization on Mars and the Moon, and civilian missions in 1000-3000 km orbits would generate significantly more power of 10's to 100's kW e for 5-10 years, or even longer. A number of design options to enhance the operation reliability and safety of these high power space reactor power systems are presented and discussed.
El-Genk, Mohamed S.
One and two-stage upflow anaerobic sludge-bed reactor pretreatment of winery wastewater at 4¢10░C
The operating performance of a single and two (in series) laboratory upflow anaerobic sludge-bed (UASB) reactors (2.7-L working\\u000a volume, recycle ratio varied from 1:1 to 1:18) treating diluted wine vinasse was investigated under psychrophilic conditions\\u000a (4¢10░C). For a single UASB reactor seeded with granular sludge, the average organic loading rates (OLRs) applied were 4.7,\\u000a 3.7, and 1.7 g of chemical
Sergey V. Kalyuzhnyi; Marina A. Gladchenko; Vladimir I. Sklyar; Yekaterina S. Kizimenko; Sergey S. Shcherbakov
Reactor Lithium Heat Pipes for HP-STMCs Space Reactor Power System
Design and performance analysis of the nuclear reactor's lithium heat pipes for a 110-kWe Heat Pipes-Segmented Thermoelectric Module Converters (HP-STMCs) Space Reactor Power system (SRPS) are presented. The evaporator length of the heat pipes is the same as the active core height (0.45 m) and the C-C finned condenser is of the same length as the STMC panels (1.5 m). The C-C finned condenser section is radiatively coupled to the collector shoes of the STMCs placed on both sides. The lengths of the adiabatic section, the values of the power throughput and the evaporator wall temperature depend on the radial location of the heat pipe in the reactor core and the number and dimensions of the potassium heat pipes in the heat rejection radiator. The reactor heat pipes have a total length that varies from 7.57 to 7.73 m, and a 0.2 mm thick Mo-14%Re wick with an average pore radius of 12 ?m. The wick is separated from the Mo-14%Re wall by a 0.5 mm annulus filled with liquid lithium, to raise the prevailing capillary limit. The nominal evaporator (or reactor) temperature varies from 1513 to 1591 K and the thermal power of the reactor is 1.6 MW, which averages 12.7 kW for each of the 126 reactor heat pipes. The power throughput per heat pipe increase to a nominal 15.24 kW at the location of the peak power in the core and to 20.31 kW when an adjacent heat pipe fails. The prevailing capillary limit of the reactor heat pipes is 28.3 kW, providing a design margin >= 28%.
Tournier, Jean-Michel; El-Genk, Mohamed S.
Fluid flow distribution system for fluidized bed reactor
This patent describes an improved flow distribution system for a catalytic reactor plenum chamber for a gas-liquid-solids ebulated bed reactor. It includes a baffled nozzle device containing at least two baffle plates usually oriented substantially normal to the nozzle inlet flow direction for providing good mixing and uniform flow distribution of gas-liquid materials in the lower portion of the plenum. It is used in a combination with distribution grid to effect a substantially uniform flow distribution of the gas/liquid mixture upwardly into the ebullated catalyst bed. A sparger can be provided in the plenum above the baffled flow distributor device for feeding additional gas-liquid mixture into the reactor. The flow distribution system provides a substantially uniform flow distribution of the gas-liquid mixture into the ebullated bed and thereby provides fouling-free operation of the reactor.
Li, A.S.; Eccles, R.M.
Dual annular rotating "windowed" nuclear reflector reactor control system
A nuclear reactor control system is provided in a nuclear reactor having a core operating in the fast neutron energy spectrum where criticality control is achieved by neutron leakage. The control system includes dual annular, rotatable reflector rings. There are two reflector rings: an inner reflector ring and an outer reflector ring. The reflectors are concentrically assembled, surround the reactor core, and each reflector ring includes a plurality of openings. The openings in each ring are capable of being aligned or non-aligned with each other. Independent driving means for each of the annular reflector rings is provided so that reactor criticality can be initiated and controlled by rotation of either reflector ring such that the extent of alignment of the openings in each ring controls the reflection of neutrons from the core.
Jacox, Michael G. (Idaho Falls, ID); Drexler, Robert L. (Idaho Falls, ID); Hunt, Robert N. M. (Idaho Falls, ID); Lake, James A. (Idaho Falls, ID)
Nuclear reactor heat transport system component low friction support system
A support column for a heavy component of a liquid metal fast breeder reactor heat transport system which will deflect when the pipes leading coolant to and from the heavy component expand or contract due to temperature changes includes a vertically disposed pipe, the pipe being connected to the heavy component by two longitudinally spaced cycloidal dovetail joints wherein the distal end of each of the dovetails constitutes a part of the surface of a large diameter cylinder and the centerlines of these large diameter cylinders intersect at right angles and the pipe being supported through two longitudinally spaced cycloidal dovetail joints wherein the distal end of each of the dovetails constitutes a part of the surface of a large diameter cylinder and the centerlines of these large diameter cylinders intersect at right angles, each of the cylindrical surfaces bearing on a flat and horizontal surface.
Wade, Elman E. (Ruffs Dale, PA)
Efficiency and mass characteristics for four gas-cooled reactor power system configurations in the 2- to 20-MWe power range are modeled. The configurations use direct and indirect Brayton cycles with and without regeneration in the power conversion loop. The prismatic ceramic core of the reactor consists of several thousand pencil-shaped tubes made from a homogeneous mixture of moderator and fuel. The heat rejection system is found to be the major contributor to system mass, particularly at high power levels. A direct, regenerated Brayton cycle with helium working fluid permits high efficiency and low specific mass for a 10-MWe system.
Fuel-failure detection system for Pakistan research reactor-1
Fuel-failure detection in nuclear reactors is important from the safety point of view. After the conversion and upgrading of Pakistan Research Reactor-1 (PARR-1), it was decided to install a fuel-failure detection system to confirm the performance and integrity of the new fuel elements. The fuel-failure detection is based on monitoring of delayed neutrons emitted from fission products leaking into the
S. K. Ayazuddin; Tariq Hayat; A. A. Qureshi; H. A. Khan
Pressurized reactor system and a method of operating the same
A method and apparatus are provided for operating a pressurized reactor system in order to precisely control the temperature within a pressure vessel in order to minimize condensation of corrosive materials from gases on the surfaces of the pressure vessel or contained circulating fluidized bed reactor, and to prevent the temperature of the components from reaching a detrimentally high level, while at the same time allowing quick heating of the pressure vessel interior volume during start-up. Super-atmospheric pressure gas is introduced from the first conduit into the fluidized bed reactor and heat derived reactions such as combustion and gasification are maintained in the reactor. Gas is exhausted from the reactor and pressure vessel through a second conduit. Gas is circulated from one part of the inside volume to another to control the temperature of the inside volume, such as by passing the gas through an exterior conduit which has a heat exchanger, control valve, blower and compressor associated therewith, or by causing natural convection flow of circulating gas within one or more generally vertically extending gas passages entirely within the pressure vessel (and containing heat exchangers, flow rate control valves, or the like therein). Preferably, inert gas is provided as a circulating gas, and the inert gas may also be used in emergency shut-down situations. In emergency shut-down reaction gas being supplied to the reactor is cut off, while inert gas from the interior gas volume of the pressure vessel is introduced into the reactor. 2 figs.
Isaksson, J.M.
A method and apparatus are provided for operating a pressurized reactor system in order to precisely control the temperature within a pressure vessel in order to minimize condensation of corrosive materials from gases on the surfaces of the pressure vessel or contained circulating fluidized bed reactor, and to prevent the temperature of the components from reaching a detrimentally high level, while at the same time allowing quick heating of the pressure vessel interior volume during start-up. Superatmospheric pressure gas is introduced from the first conduit into the fluidized bed reactor and heat derived reactions such as combustion and gassification are maintained in the reactor. Gas is exhausted from the reactor and pressure vessel through a second conduit. Gas is circulated from one part of the inside volume to another to control the temperature of the inside volume, such as by passing the gas through an exterior conduit which has a heat exchanger, control valve, blower and compressor associated therewith, or by causing natural convection flow of circulating gas within one or more generally vertically extending gas passages entirely within the pressure vessel (and containing heat exchangers, flow rate control valves, or the like therein). Preferably, inert gas is provided as a circulating gas, and the inert gas may also be used in emergency shut-down situations. In emergency shut-down reaction gas being supplied to the reactor is cut off, while inert gas from the interior gas volume of the pressure vessel is introduced into the reactor.
Isaksson, Juhani M. (Karhula, FI)
Digital, remote control system for a 2MW research reactor
A fault-tolerant programmable logic controller (PLC) and operator workstations have been programmed to replace the hard-wired relay control system in the 2-MW Bulk Shielding Reactor (BSR) at Oak Ridge National Laboratory. In addition to the PLC and remote and local operator workstations, auxiliary systems for remote operation include a video system, an intercom system, and a fiber optic communication system.
R. E. Battle; G. K. Corbett
Remote control system for a 2MW research reactor
A description is given of a fault-tolerant programmable logic controller (PLC) and operator workstations that have been programmed to replace the hard-wired relay control system in the 2 MW bulk shielding reactor at Oak Ridge National Laboratory. Auxiliary systems include a video system, an intercom system, and a fiber-optic communication system. The equipment has been designed with reliability and fail-safe
Software reliability and safety in nuclear reactor protection systems
Planning the development, use and regulation of computer systems in nuclear reactor protection systems in such a way as to enhance reliability and safety is a complex issue. This report is one of a series of reports from the Computer Safety and Reliability Group, Lawrence Livermore that investigates different aspects of computer software in reactor National Laboratory, that investigates different aspects of computer software in reactor protection systems. There are two central themes in the report, First, software considerations cannot be fully understood in isolation from computer hardware and application considerations. Second, the process of engineering reliability and safety into a computer system requires activities to be carried out throughout the software life cycle. The report discusses the many activities that can be carried out during the software life cycle to improve the safety and reliability of the resulting product. The viewpoint is primarily that of the assessor, or auditor.
Lawrence, J.D. [Lawrence Livermore National Lab., CA (United States)
Biotransformation of nitrophenols in upflow anaerobic sludge blanket reactors
Four identical bench-scale upflow anaerobic sludge blanket (UASB) reactors, R1, R2, R3 and R4, were used to assess nitrophenols degradation at four different hydraulic retention times (HRT). Reactor R1 was used as control, whereas R2, R3, and R4 were fed with 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), and 2,4-dinitrophenol (2,4-DNP), respectively. The concentration of each nitrophenol was gradually varied from 2 to
Khursheed Karim; S. K Gupta
Westinghouse Reactor Protection System Unavailability, 1984--1995
An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U. S. Westinghouse commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.
Eide, Steven Arvid; Calley, Michael Brennan; Gentillon, Cynthia Ann; Wierman, Thomas Edward; Rasmuson, D.; Marksberry, D.
General Electric Reactor Protection System Unavailability, 1984--1995
An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U. S. General Electric commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.
Eide, Steven Arvid; Calley, Michael Brennan; Gentillon, Cynthia Ann; Wierman, Thomas Edward; Hamzehee, H.; Rasmuson, D.
Westinghouse Reactor Protection System Unavailability, 1984-1995
An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U.S. Westinghouse commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.
C. D. Gentillon; D. Marksberry (USNRC); D. Rasmuson; M. B. Calley; S. A. Eide; T. Wierman (INEEL)
General Electric Reactor Protection System Unavailability, 1984-1995
An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U.S. General Electric commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.
C. D. Gentillon; D. Rasmuson (USNRC); H. Hamzehee; M. B. Calley; S. A. Eide; T. Wierman (INEEL)
Sewage treatment in an up-flow anaerobic sponge reactor followed by moving bed biofilm reactor based on polyurethane carrier material
Comparison of the performance of an up-flow anaerobic sponge reactor (UASR) versus a classical up-flow anaerobic sludge blanket (UASB) reactor for sewage treatment was investigated. Both reactors were operated at a hydraulic retention time (HRT) of 6.0 h and organic loading rate (OLR) of 2.3 kg COD m\\/d. The results obtained revealed that the UASR produced better effluent quality as
Ahmed Tawfik; Nagwa Badr; EnasAbu Taleb; Waleed El-Senousy
System modeling and reactor design studies of the Advanced Thermionic Initiative space nuclear reactor
In-core thermionic space reactor design concepts that operate at a nominal power output range of 20 to 50 kW(electric) are described. Details of the neutronic, thermionic, thermal hydraulics, and shielding performance are presented. Because of the strong absorption of thermal neutrons by natural tungsten and the large amount of natural tungsten within the reactor core, two designs are considered. An overall system design code has been developed at Oregon State University to model advanced in-core thermionic energy conversion-based nuclear reactor systems for space applications. The results show that the driverless single-cell Advanced Thermionic Initiative (ATI) configuration, which does not have driver fuel rods, proved to be more efficient than the driven core, which has driver rods. The results also show that the inclusion of the true axial and radial power distribution decrease the overall conversion efficiency. The flattening of the radial power distribution by three different methods would lead to a higher efficiency. The results show that only one TFE works at the optimum emitter temperature; all other TFEs are off the optimum performance and result in a 40% decrease of the efficiency of the overall system. The true axial profile is significantly different as there is a considerable amount of neutron leakage out of the top and bottom of the reactor. The analysis reveals that the axial power profile actually has a chopped cosine shape. For this axial profile, the reactor core overall efficiency for the driverless ATI reactor version is found to be 5.84% with a total electrical power of 21.92 kW(electric). By considering the true axial power profile instead of the uniform power profile, each TFE loses {approximately}80 W(electric).
Lee, H.H.; Abdul-Hamid, S.; Klein, A.C. [Oregon State Univ., Corvallis, OR (United States). Dept. of Nuclear Engineering Radiation Center] [Oregon State Univ., Corvallis, OR (United States). Dept. of Nuclear Engineering Radiation Center
Optimization of the performance of an integrated anaerobic-aerobic system for domestic wastewater treatment.
A promising system consisting of Up-flow Anaerobic Sludge Blanket (UASB) and Down-Flow Hanging Sponge (DHS) system was investigated for removal of COD, BOD(5) fractions, ammonia and faecal coliform from domestic wastewater. The combined system was operated at different HRTs of 16, 11 and 8 h. The results indicate that increasing the total HRT from 8 to 16 h significantly (p < 0.05) improves the COD(total) and BOD(5 total) removal mainly as a result of a higher removal of COD(soluble), BOD(soluble), COD(particulate) and BOD(particulate). The main part of coarse suspended solids was removed in the UASB reactor (76.4+/-18%) and the remaining portion was adsorbed and/or enmeshed and degraded in the biomass of the DHS system. The combined system achieved a substantial reduction of total suspended solids (TSS) resulting in an average overall percentage removal of 94+/-6% (HRT = 16 h) and 89.5+/-7.8% (HRT = 8 h). Faecal coliform reduction was significantly improved when increasing the total HRT from 8 to 16 h. Residual counts of faecal coliform were 3.1 x 10(3)/100 ml at a total HRT of 16 h, and 2.8 x 10(4)/100 ml at total HRT of 8 h, corresponding to overall removal efficiency of 99.97+/-0.03 and 99.6+/-0.3% respectively. Despite the increase of ammonia concentration as a result of protein hydrolysis in the UASB reactor, a substantial removal of ammonia was achieved in the DHS system. The results obtained show that decreasing the OLR imposed to DHS system from 2.6 to 1.6 kg COD/m(3).d significantly (p < 0.05) improves the removal efficiency of ammonia by a value of 29%. However, the removal efficiency of ammonia is not further increased when decreasing the OLR from 1.6 to 1.3 kg COD/m(3).d. The discharged sludge from UASB + DHS system exerts a good settling property and partially stabilized.DHS profile results have shown that the major part of COD, BOD(5), and TSS was removed in the upper part of the system, consequently, the nitrification process was occurring in the lower part of the DHS system. PMID:18653953
Tawfik, A; El-Gohary, F; Ohashi, A; Harada, H
Hybrid Plasma Reactor/Filter for Transportable Collective Protection Systems
Pacific Northwest National Laboratory (PNNL) has performed an assessment of a Hybrid Plasma/Filter system as an alternative to conventional methods for collective protection. The key premise of the hybrid system is to couple a nonthermal plasma (NTP) reactor with reactive adsorption to provide a broader envelope of protection than can be provided through a single-solution approach. The first step uses highly reactive species (e.g. oxygen radicals, hydroxyl radicals, etc.) created in a nonthermal plasma (NTP) reactor to destroy the majority (~75% - 90%) of an incoming threat. Following the NTP reactor an O3 reactor/filter uses the O3 created in the NTP reactor to further destroy the remaining organic materials. This report summarizes the laboratory development of the Hybrid Plasma Reactor/Filter to protect against a æworst-caseÆ simulant, methyl bromide (CH3Br), and presents a preliminary engineering assessment of the technology to Joint Expeditionary Collective Protection performance specifications for chemical vapor air purification technologies.
Josephson, Gary B.; Tonkyn, Russell G.; Frye, J. G.; Riley, Brian J.; Rappe, Kenneth G.
Reactor protection system with automatic self-testing and diagnostic
A reactor protection system is disclosed having four divisions, with quad redundant sensors for each scram parameter providing input to four independent microprocessor-based electronic chassis. Each electronic chassis acquires the scram parameter data from its own sensor, digitizes the information, and then transmits the sensor reading to the other three electronic chassis via optical fibers. To increase system availability and reduce false scrams, the reactor protection system employs two levels of voting on a need for reactor scram. The electronic chassis perform software divisional data processing, vote 2/3 with spare based upon information from all four sensors, and send the divisional scram signals to the hardware logic panel, which performs a 2/4 division vote on whether or not to initiate a reactor scram. Each chassis makes a divisional scram decision based on data from all sensors. Automatic detection and discrimination against failed sensors allows the reactor protection system to automatically enter a known state when sensor failures occur. Cross communication of sensor readings allows comparison of four theoretically ``identical`` values. This permits identification of sensor errors such as drift or malfunction. A diagnostic request for service is issued for errant sensor data. Automated self test and diagnostic monitoring, sensor input through output relay logic, virtually eliminate the need for manual surveillance testing. This provides an ability for each division to cross-check all divisions and to sense failures of the hardware logic. 16 figs.
A reactor protection system having four divisions, with quad redundant sensors for each scram parameter providing input to four independent microprocessor-based electronic chassis. Each electronic chassis acquires the scram parameter data from its own sensor, digitizes the information, and then transmits the sensor reading to the other three electronic chassis via optical fibers. To increase system availability and reduce false scrams, the reactor protection system employs two levels of voting on a need for reactor scram. The electronic chassis perform software divisional data processing, vote 2/3 with spare based upon information from all four sensors, and send the divisional scram signals to the hardware logic panel, which performs a 2/4 division vote on whether or not to initiate a reactor scram. Each chassis makes a divisional scram decision based on data from all sensors. Automatic detection and discrimination against failed sensors allows the reactor protection system to automatically enter a known state when sensor failures occur. Cross communication of sensor readings allows comparison of four theoretically "identical" values. This permits identification of sensor errors such as drift or malfunction. A diagnostic request for service is issued for errant sensor data. Automated self test and diagnostic monitoring, sensor input through output relay logic, virtually eliminate the need for manual surveillance testing. This provides an ability for each division to cross-check all divisions and to sense failures of the hardware logic.
A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.
TREAT (Transient Reactor Test Facility) reactor control rod scram system simulations and testing
Air cylinders moving heavy components (100 to 300 lbs) at high speeds (above 300 in/sec) present a formidable end-cushion-shock problem. With no speed control, the moving components can reach over 600 in/sec if the air cylinder has a 5 ft stroke. This paper presents an overview of a successful upgrade modification to an existing reactor control rod drive design using a computer model to simulate the modified system performance for system design analysis. This design uses a high speed air cylinder to rapidly insert control rods (278 lb moved 5 ft in less than 300 msec) to scram an air-cooled test reactor. Included is information about the computer models developed to simulate high-speed air cylinder operation and a unique new speed control and end cushion design. A patent application is pending with the US Patent Trade Mark Office for this system (DOE case number S-68,622). The evolution of the design, from computer simulations thru operational testing in a test stand (simulating in-reactor operating conditions) to installation and use in the reactor, is also described. 6 figs.
Solbrig, C.W.; Stevens, W.W.
Dynamic analysis of gas-core reactor system
A heat transfer analysis was incorporated into a previously developed model CODYN to obtain a model of open-cycle gaseous core reactor dynamics which can predict the heat flux at the cavity wall. The resulting model was used to study the sensitivity of the model to the value of the reactivity coefficients and to determine the system response for twenty specified perturbations. In addition, the model was used to study the effectiveness of several control systems in controlling the reactor. It was concluded that control drums located in the moderator region capable of inserting reactivity quickly provided the best control.
Turner, K. H., Jr.
System Study: Reactor Core Isolation Cooling 1998¢2012
This report presents an unreliability evaluation of the reactor core isolation cooling (RCIC) system at 31 U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2012 for selected components were obtained from the Equipment Performance and Information Exchange (EPIX). The unreliability results are trended for the most recent 10 year period while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing trend was identified in the HPCI results. Statistically significant decreasing trends were identified for RCIC start-only and 8-hour trends.
T. E. Wierman
Optimized Battery-Type Reactor Primary System Design Utilizing Lead
A number of small and medium size reactors are being developed worldwide as well as large electricity generation reactors for co-generation, district heating or desalination. The Seoul National University has started to develop 23 MWth BORIS (Battery Optimized Reactor Integral System) as a multi-purpose reactor. BORIS is an integral-type optimized fast reactor with an ultra long life core. BORIS is being designed to meet the Generation IV nuclear energy system goals of sustainability, safety, reliability and economics. Major features of BORIS include 20 consecutive years of operation without refueling; elimination of an intermediate heat transport loop and main coolant pump; open core without individual subassemblies; inherent negative reactivity feedback; and inherent load following capability. Its one mission is to provide incremental electricity generation to match the needs of developing nations and especially remote communities without major electrical grid connections. BORIS consists of a reactor module, heat exchanger, coolant module, guard vessel, reactor vessel auxiliary cooling system (RVACS), secondary system, containment and the seismic isolation. BORIS is designed to generate 10 MWe with the resulting thermal efficiency of 45 %. BORIS uses lead as the primary system coolant because of the inherent safety of the material. BORIS is coupled with a supercritical carbon dioxide Brayton cycle as the secondary system to gain a high cycle efficiency in the range of 45 %. The reference core consists of 757 fuel rods without assembly with an active core height of 0.8 m. The BORIS core consists of single enrichment zone composed of a Pu-MA (minor actinides)-U-N fuel and a ferritic-martensitic stainless steel clad. This study is intended to set up appropriate reactor vessel geometry by performing thermal hydraulic analysis on RVACS using computational fluid dynamics codes; to examine the liquid metal coolant behavior along the subchannels; to find out whether the given flux profiles and geometrical arrangement of fuel rods yield reasonable flow distribution during nominal operation using a subchannel analysis code; and to determine the natural circulation capability of the BORIS primary coolant system by calculating the total pressure drop in the system. (authors)
Yu, Yong H.; Son, Hyoung M.; Lee, Il S.; Suh, Kune Y. [Seoul National University, San 56-1 Sillim-dong, Gwanak-gu, Seoul, 151-742 (Korea, Republic of)
Dispersed plug flow model for upflow anaerobic sludge bed reactors with focus on granular sludge dynamics
A new approach to model upflow anaerobic sludge bed (UASB)-reactors, referred to as a one-dimensional dispersed plug flow\\u000a model, was developed. This model focusses on the granular sludge dynamics along the reactor height, based on the balance between\\u000a dispersion, sedimentation and convection using one-dimensional (with regard to reactor height) equations. A universal description\\u000a of both the fluid hydrodynamics and granular
Sergey V. Kalyuzhnyi; Vyacheslav V. Fedorovich; Piet Lens
Two platinum catalyst reactor subsystems have been built for the new Tritium Emissions Reduction Facility (TERF) at Mound. The two parallel subsystems each consist of three major components: a passive conservation heat exchanger, an electric preheater, and a catalytic reactor. All subsystem components and interconnecting piping are fabricated from Inconel 625 for high temperature strength and corrosion resistance. System connections are welded for longevity and reliability. Active elements are backed up by installed spares, and the reactor catalyst is replaceable. Since double containment of tritium processing systems is an important safety concept, the entire subsystem is enclosed in a stainless steel glovebox. Careful planning during the design phase created thermal isolation from the glovebox, and the ability to translate the entire subsystem from the glovebox for major maintenance. 4 refs.
Wieneke, R.E.
Modifications Done in the IPR-R1 Reactor and Their Auxiliary Systems.
The improvements done in the IPR-R1 reactor for adequateness of operation conditions and increase of irradiation sample capability. The cooling systems, reactor pool, system of control rods were substituted. The optimization of transfer pneumatic system w...
F. Maretti V. A. Amorim J. G. Coura
Development and Assessment of Advanced Reactor Core Protection System
An advanced core protection system for a pressurized water reactor, Reactor Core Protection System(RCOPS), was developed by adopting a high performance hardware platform and optimal system configuration. The functional algorithms of the core protection system were also improved to enhance the plant availability by reducing unnecessary reactor trips and increasing operational margin. The RCOPS consists of four independent safety channels providing a two-out-of-four trip logic. The reliability analysis using the reliability block diagram method showed the unavailability of the RCOPS to be lower than the conventional system. The failure mode and effects analysis demonstrated that the RCOPS does not lose its intended safety functions for most failures. New algorithms for the RCOPS functional design were implemented in order to avoid unnecessary reactor trips by providing auxiliary pre-trip alarms and signal validation logic for the control rod position. The new algorithms in the RCOPS were verified by comparing the RCOPS calculations with reference results. The new thermal margin algorithm for the RCOPS was expected to increase the operational margin to the limit for Departure from Nucleate Boiling Ratio (DNBR) by approximately 1%.
in, Wang-Kee; Park, Young-Ho; Baeg, Seung-Yeob
Remote control system for a 2-MW research reactor
A fault-tolerant programmable logic controller (PLC) and operator workstations have been programmed to replace the hard-wired relay control system in the 2-MW Bulk Shielding Reactor at Oak Ridge National Laboratory. In addition to the PLC and remote and local operator workstations, auxiliary systems include a video system, an intercom system, and a fiber optic communication system. The equipment has been designed with reliability and fail-safe features as important considerations. Significant features of the system are described. 2 refs., 4 figs., 1 tab.
Battle, R.E.; Corbett, G.K.
Light Water Breeder Reactor rod removal system (LWBR Development Program)
This report describes the design and operation of the robotic equipment for remote withdrawal of fuel rods from the Light Water Breeder Reactor (LWBR) fuel modules for proof-of-breeding assay and physical examinations. The Rod Removal System (RRS) was automated to minimize operator errors in removing specified rods while maintaining maximum control over forces applied during removal to preclude damage. The
G. Fodor; T. J. Kikta; R. L. Matchett; D. R. Roof; R. Wilczynski
Modification of the Core Cooling System of TRIGA 2000 Reactor
To accomplish safety requirements, a set of actions has to be performed following the recommendations of the IAEA safety series 35 applied to research reactor. Such actions are considered in modernization of the old system, improving the core cooling system and safety evaluations. Due to the complexity of the process and the difficulty in putting the apparatus in the reactor core, analytical and experimental study on the determination of flow and temperature distribution in the whole coolant channel are difficult to be done. In the present work, a numerical study of flow and temperature distribution in the coolant channel of TRIGA 2000 has been carried out using CFD package. For this study, simulations were carried out on 3-D tested model. The model consists of the reactor tank, thermal and thermalizing column, reflector, rotary specimen rack, chimney, fuel element, primary pipe, diffuser, beam tube and a part of the core are constructed by 1.50 million unstructured tetrahedral cell elements. The results show that for the initial condition (116 fuel elements in the core) and for the inlet temperature of 24░C and the primary velocity of 5.6 m/s, there no boiling phenomena occur in the coolant channel. Due to this result, it is now possible to improve the core cooling system of TRIGA 2000 reactor. Meanwhile, forced flow from the diffuser system only affected the flow pattern in the outside of chimney and put on a small effect to the fluid flow's velocity in the inside of chimney.
Umar, Efrizon; Fiantini, Rosalina
To accomplish safety requirements, a set of actions has to be performed following the recommendations of the IAEA safety series 35 applied to research reactor. Such actions are considered in modernization of the old system, improving the core cooling system and safety evaluations. Due to the complexity of the process and the difficulty in putting the apparatus in the reactor core, analytical and experimental study on the determination of flow and temperature distribution in the whole coolant channel are difficult to be done. In the present work, a numerical study of flow and temperature distribution in the coolant channel of TRIGA 2000 has been carried out using CFD package. For this study, simulations were carried out on 3-D tested model. The model consists of the reactor tank, thermal and thermalizing column, reflector, rotary specimen rack, chimney, fuel element, primary pipe, diffuser, beam tube and a part of the core are constructed by 1.50 million unstructured tetrahedral cell elements. The results show that for the initial condition (116 fuel elements in the core) and for the inlet temperature of 24 deg. C and the primary velocity of 5.6 m/s, there no boiling phenomena occur in the coolant channel. Due to this result, it is now possible to improve the core cooling system of TRIGA 2000 reactor. Meanwhile, forced flow from the diffuser system only affected the flow pattern in the outside of chimney and put on a small effect to the fluid flow's velocity in the inside of chimney.
Umar, Efrizon; Fiantini, Rosalina [National Nuclear Energy Agency of Indonesia, Jalan Tamansari 71, Bandung, 40132 (Indonesia)
A microprocessor tester for the treat upgrade reactor trip system
The upgrading of the Transient Reactor Test (TREAT) Facility at ANL-Idaho has been designed to provide additional experimental capabilities for the study of core disruptive accident (CDA) phenomena. To improve the analytical extrapolation of test results to full-size assembly bundles, the facility upgrade will increase the maximum size of the test bundle from 7 to 37 fuel pins. By creating a core convertor zone around the test location, the neutron spectrum incident on the test assembly will be hardened and the maximum energy deposited in the sample will be increased. In addition, a programmable Automated Reactor Control System (ARCS) will permit high-power transients up to 11,000 MW having a controlled reactor period of from 15 to 0.1 sec. These modifications to the core neutronics will improve simulation of LMFBR accident conditions. Finally, a sophisticated, multiply-redundant safety system, the Reactor Trip System (RTS), will provide safe operation for both steady state and transient production operating modes. To insure that this complex safety system is functioning properly, a Dedicated Microprocessor Tester (DMT) has been implemented to perform a thorough checkout of the RTS prior to all TREAT operations. A quantitative reliability analysis of the RTS shows that the unreliability, that is, the probability of failure, is acceptable for a 10 hour mission time or risk interval.
Water quality diagnosis system for evaluation of reactor water impurities
In recent years, the methods of water chemistry control in boiling water reactor (BWR) plants have become more and more complicated because of the increasingly higher purity of water quality as a result of the sophistication of water chemistry control techniques. A water quality diagnosis system has been developed to improve the reliability of and achieve a high level of
Toshihiko Fukumoto; Yoichi Hayashi; Nobuyuki Oota; Hiroo Igarashi
Architecture of the ETR (Experimental Test Reactor) Systems Code.
TETRA, a tokamak systems code capable of modeling experimental test reactors (ETRs), was developed in a joint effort by participants of the fusion community. The first version of this code was constructed to model devices similar to the Tokamak Ignition/B...
R. L. Reid J. D. Galambos
Compatibility of Refractory Materials for Nuclear Reactor Poison Control Systems.
Metal-clad poison rods have been considered for the control system of an advanced space power reactor concept studied at the NASA Lewis Research Center. Such control rods may be required to operate at temperatures of about 140O C. Selected poison material...
J. H. Sinclair
A Pyrovidicon-based Inspection System for Nuclear Reactor Safety
At the Savannah River Nuclear Facility irradiated assemblies are conveyed through the air from the reactor to a discharge\\/entry channel, where they are immersed in water. This paper addresses the monitoring of the temperature of these assemblies while they are in transit during the discharge cycle. To accomplish this, a remotely controlled and monitored radiation-hardened thermal imaging and alarm system
Pressure suppression system for a nuclear reactor safety vessel
A pressure suppression system for a safety vessel is described. It ; consists of a pressure enclosure of steel or concrete for a liquid-cooled nuclear ; reactor with a condensation chamber with toroidal floor (flooring, platform, ; ceiling) in the form of a circular cylinder in the interior of which parallel to ; the axis, not filling the entire cylinder,
W. Ullrich; K. H. Lohse; J. Leuteritz; G. Zeitzschel; R. Fassl
Modeling and performance of the MHTGR (Modular High-Temperature Gas-Cooled Reactor) reactor cavity cooling system
The Reactor Cavity Cooling System (RCCS) of the Modular High- Temperature Gas-Cooled Reactor (MHTGR) proposed by the U.S. Department of Energy is designed to remove the nuclear afterheat passively in the event that neither the heat transport system nor the shutdown cooling circulator subsystem is available. A computer dynamic simulation for the physical and mathematical modeling of and RCCS is
Expert systems for fault diagnosis in nuclear reactor control
An expert system for accident analysis and fault diagnosis for the Loss Of Fluid Test (LOFT) reactor, a small scale pressurized water reactor, was developed for a personal computer. The knowledge of the system is presented using a production rule approach with a backward chaining inference engine. The data base of the system includes simulated dependent state variables of the LOFT reactor model. Another system is designed to assist the operator in choosing the appropriate cooling mode and to diagnose the fault in the selected cooling system. The response tree, which is used to provide the link between a list of very specific accident sequences and a set of generic emergency procedures which help the operator in monitoring system status, and to differentiate between different accident sequences and select the correct procedures, is used to build the system knowledge base. Both systems are written in TURBO PROLOG language and can be run on an IBM PC compatible with 640k RAM, 40 Mbyte hard disk and color graphics.
Jalel, N. A.; Nicholson, H.
Safety actions due to nuclear vaniables (neutron flux, period) are ; considered. The safety system connected with the period channels is studied, the ; criteria for the determination of the characteristic parameters are given with ; respect either to the response time or to the possibility of spurious actions. A ; comparison is made between the safety system related to
S. Barabaschi; A. Mathis
Space-reactor electric systems: subsystem technology assessment
This report documents the subsystem technology assessment. For the purpose of this report, five subsystems were defined for a space reactor electric system, and the report is organized around these subsystems: reactor; shielding; primary heat transport; power conversion and processing; and heat rejection. The purpose of the assessment was to determine the current technology status and the technology potentials for different types of the five subsystems. The cost and schedule needed to develop these potentials were estimated, and sets of development-compatible subsystems were identified.
Anderson, R.V.; Bost, D.; Determan, W.R.
Operation of staged membrane oxidation reactor systems
A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.
Repasky, John Michael
A gas-cooled reactor surface power system
A human outpost on Mars requires plentiful power to assure survival of the astronauts. Anywhere from 50 to 500 kW of electric power (kWe) will be needed, depending on the number of astronauts, level of scientific activity, and life-cycle closure desired. This paper describes a 250-kWe power system based on a gas-cooled nuclear reactor with a recuperated closed Brayton cycle conversion system. The design draws upon the extensive data and engineering experience developed under the various high-temperature gas cooled reactor programs and under the SP-100 program. The reactor core is similar in power and size to the research reactors found on numerous university campuses. The fuel is uranium nitride clad in Nb1%Zr, which has been extensively tested under the SP-100 program. The fuel rods are arranged in a hexagonal array within a BeO block. The BeO softens the spectrum, allowing better use of the fuel and stabilizing the geometry against deformation during impact or other loadings. The system has a negative temperature feedback coefficient so that the power level will automatically follow a variable load without the need for continuous adjustment of control elements. Waste heat is removed by an air-cooled heat exchanger using cold Martian air. The amount of radioactivity in the reactor at launch is very small (less than a Curie, and about equal to a truckload of uranium ore). The system will need to be engineered so that criticality can not occur for any launch accident. This system is also adaptable for electric propulsion or life-support during transit to and from Mars.
Lipinski, Ronald J.; Wright, Steven A.; Lenard, Roger X.; Harms, Gary A. [Sandia National Laboratories, MS-1146, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States)
Evaluation of a Reactor On-Line Uncertainty Monitoring System
Robust control designs were developed to better match experimental conditions available in the TRIGA reactor. A first-order weighting function is specified for each operating range in the robust design to limit the maximum tracking error. Inclusion of the performance-weighting function as the on-line filter is discussed as a possible on-line performance-monitoring method. The scheme to evaluate an on-line uncertainty monitoring system for a robust reactor controller is shown. TRIGA reactor experiments were conducted to evaluate on-line performance-monitoring techniques. It is concluded that the observed robust-control performance-monitoring characteristics can be incorporated in an on-line decision-making process to choose appropriate robust control selection and enforcement.
Edwards, Robert M.; He, Weidong
Mechanical damage experience in major light water reactor systems
This paper describes the nuclear power industry's experience with mechanical (as opposed to thermal or electrochemical) damage in the major systems of light water reactor (LWR) plants. Almost all of the occurrences of damage were caused by mechanical vibration. The sources of vibration include flow-induced vibration, water-hammer events, and pump and valve vibration. However, the damage has sometimes been initiated or aggravated by other sources, such as stress corrosion cracking, loss of preload, or corrosion-fatigue. Mechanical vibration can also cause metal loss in the walls of thin tubes when they impact with their supports. Some of the components that have experienced mechanical damage are reactor coolant pump shafts, PWR and BWR reactor vessel internals, PWR instrument tubes, thermal sleeves in piping, and steam generator tubes. Various mitigation methods can be implemented to reduce or eliminate these problems. 18 refs., 5 figs., 1 tab.
Ware, A.G.
Reducing thermal deposits in endothermic fuel reactors of propulsion systems
An endothermic hydrocarbon fuel system is described which avoids thermally induced coking on the catalytic surfaces of an heat exchanger used as a reactor to dehydrogenate the fuel so that it provides a heat sink for the heat exchanger for cooling parts of high speed aircraft. The invention provides a means to feed an acceptable concentration of hydrogen to the reactor feed stock, wherein the feed stock is a portion of the endothermic hydrocarbon fuel that is catalytically dehydrogenated to provide a heat sink. The preferred embodiment uses Methylcyclohexane as a fuel and provides a return loop to recycle a fraction of the reaction products to provide the hydrogen to the reactor feedstock. 1 fig.
Coffinberry, G.A.; Epstein, M.J.
Light-Water Reactors Reference System Classification for the European Reliability Data System (ERDS).
The reference system classification represents a basic stage in the organization of the European Reliability Data System (ERDS) for light-water reactors, a project actually in development at the Joint Research Centre, Ispra. This project is concerned with...
M. Melis G. Mancini
The reference system classification represents a basic stage in the organization of the European Reliability Data System (ERDS) for light-water reactors, a project under development at the Joint Research Centre, Ispra. The project is concerned with operat...
Computer study of emergency shutdowns of a 60-kilowatt reactor Brayton space power system
A digital computer study of emergency shutdowns of a 60-kWe reactor Brayton power system was conducted. Malfunctions considered were (1) loss of reactor coolant flow, (2) loss of Brayton system gas flow, (3)turbine overspeed, and (4) a reactivity insertion error. Loss of reactor coolant flow was the most serious malfunction for the reactor. Methods for moderating the reactor transients due to this malfunction are considered.
Tew, R. C.; Jefferies, K. S.
Comparative evaluation of fuel utilisation by different thermal reactor systems.
A comparative assessment of fuel utilization efficiency of pressurised water reactors, pressure tube type pressurised heavy water reactors, pressure vessel type pressurised heavy water reactors and high temperature gas cooled graphite reactors operating o...
M. R. Balakrishnan
Expert system for online surveillance of nuclear reactor coolant pumps
An expert system for online surveillance of nuclear reactor coolant pumps. This system provides a means for early detection of pump or sensor degradation. Degradation is determined through the use of a statistical analysis technique, sequential probability ratio test, applied to information from several sensors which are responsive to differing physical parameters. The results of sequential testing of the data provide the operator with an early warning of possible sensor or pump failure.
Gross, Kenny C. (Bolingbrook, IL); Singer, Ralph M. (Naperville, IL); Humenik, Keith E. (Columbia, MD)
Characterisation of microbial floras and functional gene levels in an anaerobic/aerobic bio-reactor for the degradation of carboxymethyl cellulose.
The current study determined the carboxymethyl cellulose (CMC) degradation efficiency, dominant microbial flora, eubacteria and archaebacteria characteristics, and expression levels of genes cel5A, cel6B, and bglC in an anaerobic/aerobic bio-reactor consisting of two-stage UASB (U1 and U2) and two-stage BAF (B1 and B2). The results showed that under three CMC loads, the CMC degradation efficiency of the UASB-BAF system was 91.25%, 80.44%, and 78.73%, respectively. At higher CMC loads, the degradation of cellulose and transformation to cellobiose in U1 was higher, while the transformation to glucose was lower. The results of DGGE and real-time PCR indicated that cellulose degradation bacteria are dominant in U1, cellulose degradation bacteria and cellulose degradation symbiosis bacteria are dominant in B1, and non-cellulose degradation symbiosis bacteria are dominant in both U2 and B2. The rate-limiting enzyme gene of cellulose degradation in U1, B1, and B2 is cel6B, but it is cel5A in U2. PMID:22576945
Ji, Guodong; Wang, Chen; Guo, Feng
The technical limits for the optimum design of a reactor are defined in ; diagrams by the maximum heat velocity of the fuel elements and by the indices of ; the cooling system (degree of cooling efficiency, reboil margin, and reactor ; index). The so-called marginal capacity'' of a reactor is determined by the ; power limits of a reactor
Micro-Fluidic Chemical Reactor Systems: Development, Scale-Up and Demonstration.
This report summarized advances in microfluidic chemical reactor systems obtained using microfabrication techniques. Using these techniques, reduction in size and integration of multiple functions for chemical reactor systems were realized. Issues in comb...
K. F. Jensen
Kalman filter application for distributed parameter estimation in reactor systems
An application of the Kalman filter has been developed for the real-time identification of a distributed parameter in a nuclear power plant. This technique can be used to improve numerical method-based best-estimate simulation of complex systems such as nuclear power plants. The application to a reactor system involves a unique modal model that approximates physical components, such as the reactor, as a coupled oscillator, i.e., a modal model with coupled modes. In this model both states and parameters are described by an orthogonal expansion. The Kalman filter with the sequential least-squares parameter estimation algorithm was used to estimate the modal coefficients of all states and one parameter. Results show that this state feedback algorithm is an effective way to parametrically identify a distributed parameter system in the presence of uncertainties.
Martin, R.P.; Edwards, R.M. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Nuclear Engineering
Development of a core follow calculational system for research reactors
Over the last few years a comprehensive PWR and MTR core analysis code system based on modern reactor physics methods has been under development by the Atomic Energy Corporation of South Africa. This system, known as OSCAR-3, will incorporate a customized graphical user interface and data management system to ensure user-friendliness and good quality control. The system has now reached the stage of development where it can be used for practical MTR core analyses. This paper describes the current capabilities of the components of the OSCAR-3 package, their integration within the package, and outlines future developments.
Mueller, E.Z.; Ball, G.; Joubert, W.R. [and others
78 FR 41436 - Proposed Revision to Treatment of Non-Safety Systems for Passive Advanced Light Water Reactors
...Non-Safety Systems for Passive Advanced Light Water Reactors AGENCY: Nuclear Regulatory...Systems (RTNSS) for Passive Advanced Light Water Reactors.'' The NRC seeks public...Systems (RTNSS) for Passive Advanced Light Water Reactors.'' This area...
Summary of space nuclear reactor power systems, 1983--1992
This report summarizes major developments in the last ten years which have greatly expanded the space nuclear reactor power systems technology base. In the SP-100 program, after a competition between liquid-metal, gas-cooled, thermionic, and heat pipe reactors integrated with various combinations of thermoelectric thermionic, Brayton, Rankine, and Stirling energy conversion systems, three concepts:were selected for further evaluation. In 1985, the high-temperature (1,350 K), lithium-cooled reactor with thermoelectric conversion was selected for full scale development. Since then, significant progress has been achieved including the demonstration of a 7-y-life uranium nitride fuel pin. Progress on the lithium-cooled reactor with thermoelectrics has progressed from a concept, through a generic flight system design, to the design, development, and testing of specific components. Meanwhile, the USSR in 1987--88 orbited a new generation of nuclear power systems beyond the, thermoelectric plants on the RORSAT satellites. The US has continued to advance its own thermionic fuel element development, concentrating on a multicell fuel element configuration. Experimental work has demonstrated a single cell operating time of about 1 1/2-y. Technology advances have also been made in the Stirling engine; an advanced engine that operates at 1,050 K is ready for testing. Additional concepts have been studied and experiments have been performed on a variety of systems to meet changing needs; such as powers of tens-to-hundreds of megawatts and highly survivable systems of tens-of-kilowatts power.
Buden, D.
A Spouted Bed Reactor Monitoring System for Particulate Nuclear Fuel
Conversion and coating of particle nuclear fuel is performed in spouted (fluidized) bed reactors. The reactor must be capable of operating at temperatures up to 2000░C in inert, flammable, and coating gas environments. The spouted bed reactor geometry is defined by a graphite retort with a 2.5 inch inside diameter, conical section with a 60░ included angle, and a 4 mm gas inlet orifice diameter through which particles are removed from the reactor at the completion of each run. The particles may range from 200 Ąm to 2 mm in diameter. Maintaining optimal gas flow rates slightly above the minimum spouting velocity throughout the duration of each run is complicated by the variation of particle size and density as conversion and/or coating reactions proceed in addition to gas composition and temperature variations. In order to achieve uniform particle coating, prevent agglomeration of the particle bed, and monitor the reaction progress, a spouted bed monitoring system was developed. The monitoring system includes a high-sensitivity, low-response time differential pressure transducer paired with a signal processing, data acquisition, and process control unit which allows for real-time monitoring and control of the spouted bed reactor. The pressure transducer is mounted upstream of the spouted bed reactor gas inlet. The gas flow into the reactor induces motion of the particles in the bed and prevents the particles from draining from the reactor due to gravitational forces. Pressure fluctuations in the gas inlet stream are generated as the particles in the bed interact with the entering gas stream. The pressure fluctuations are produced by bulk movement of the bed, generation and movement of gas bubbles through the bed, and the individual motion of particles and particle subsets in the bed. The pressure fluctuations propagate upstream to the pressure transducer where they can be monitored. Pressure fluctuation, mean differential pressure, gas flow rate, reactor operating temperature data from the spouted bed monitoring system are used to determine the bed operating regime and monitor the particle characteristics. Tests have been conducted to determine the sensitivity of the monitoring system to the different operating regimes of the spouted particle bed. The pressure transducer signal response was monitored over a range of particle sizes and gas flow rates while holding bed height constant. During initial testing, the bed monitoring system successfully identified the spouting regime as well as when particles became interlocked and spouting ceased. The particle characterization capabilities of the bed monitoring system are currently being tested and refined. A feedback control module for the bed monitoring system is currently under development. The feedback control module will correlate changes in the bed response to changes in the particle characteristics and bed spouting regime resulting from the coating and/or conversion process. The feedback control module will then adjust the gas composition, gas flow rate, and run duration accordingly to maintain the bed in the desired spouting regime and produce optimally coated/converted particles.
D. S. Wendt; R. L. Bewley; W. E. Windes
77 FR 15812 - Initial Test Program of Condensate and Feedwater Systems for Light-Water Reactors
...of Condensate and Feedwater Systems for Light-Water Reactors AGENCY: Nuclear Regulatory...of Condensate and Feedwater Systems for Light- Water Reactors.'' DG-1265 is proposed...condensate and feedwater systems in all types of light water reactor facilities licensed...
A Symbiotic System Of A Large Fast Breeder Reactor And Small-Sized, Long Life, Thorium Satellite Reactors - General Introduction
A SYMBIOTIC SYSTEM OF A LARGE FAST BREEDER REACTOR AND SMALL-SIZED, LONG LIFE, THORIUM SATELLITE REACTORS - GENERAL INTRODUCTION. Responding to the rapidly increasing growth of energy demand in the less- developed and developing countries, use of fission nuclear energy best mixed with other primary energy resources is inevitable short- and mid-term options. However, requirements of high capital investment and
Peng Hong Liem; Permana Sidik; Naoyuki Takagi; Hiroshi Sekimoto
Monitoring nuclear reactor systems using neural networks and fuzzy logic
A new approach is presented that demonstrates the potential of trained artificial neural networks (ANNs) as generators of membership functions for the purpose of monitoring nuclear reactor systems. ANN`s provide a complex-to-simple mapping of reactor parameters in a process analogous to that of measurement. Through such ``virtual measurements`` the value of parameters with operational significance, e.g., control-valve-disk-position, valve-line-up or performance can be determined. In the methodology presented the output of a virtual measuring device is a set of membership functions which independently represent different states of the system. Utilizing a fuzzy logic representation offers the advantage of describing the state of the system in a condensed form, developed through linguistic descriptions and convenient for application in monitoring, diagnostics and generally control algorithms. The developed methodology is applied to the problem of measuring the disk position of the secondary flow control valve of an experimental reactor using data obtained during a start-up. The enhanced noise tolerance of the methodology is clearly demonstrated as well as a method for selecting the actual output. The results suggest that it is possible to construct virtual measuring devices through artificial neural networks mapping dynamic time series to a set of membership functions and thus enhance the capability of monitoring systems. 8 refs., 11 figs., 1 tab.
Ikonomopoulos, A.; Tsoukalas, L.H.; Uhrig, R.E. [Tennessee Univ., Knoxville, TN (United States); Mullens, J.A. [Tennessee Univ., Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States)
Completely modular Thermionic Reactor Ion Propulsion System (TRIPS)
The nuclear reactor powered ion propulsion system described is an advanced completely modularized system which lends itself to development of prototype and/or flight type components without the need for complete system tests until late in the development program. This modularity is achieved in all of the subsystems and components of the electric propulsion system including (1) the thermionic fuel elements, (2) the heat rejection subsystem (heat pipes), (3) the power conditioning modules, and (4) the ion thrusters. Both flashlight and external fuel type in-core thermionic reactors are considered as the power source. The thermionic fuel elements would be useful over a range of reactor power levels. Electrical heated acceptance testing in their flight configuration is possible for the external fuel case. Nuclear heated testing by sampling methods could be used for acceptance testing of flashlight fuel elements. The use of heat pipes for cooling the collectors and as a means of heat transport to the radiator allows early prototype or flight configuration testing of a small module of the heat rejection subsystem as opposed to full scale liquid metal pumps and radiators in a large vacuum chamber. The power conditioner (p/c) is arranged in modules with passive cooling.
Peelgren, M. L.; Kikin, G. M.; Sawyer, C. D.
Monitoring system for a liquid-cooled nuclear fission reactor
A monitoring system for detecting changes in the liquid levels in various regions of a water-cooled nuclear power reactor, viz., in the downcomer, in the core, in the inlet and outlet plenums, at the head, and elsewhere; and also for detecting changes in the density of the liquid in these regions. A plurality of gamma radiation detectors are used, arranged vertically along the outside of the reactor vessel, and collimator means for each detector limits the gamma-radiation it receives as emitting from only isolated regions of the vessel. Excess neutrons produced by the fission reaction will be captured by the water coolant, by the steel reactor walls, or by the fuel or control structures in the vessel. Neutron capture by steel generates gamma radiation having an energy level of the order of 5-12 MeV, whereas neutron capture by water provides an energy level of approximately 2.2 MeV, and neutron capture by the fission fuel or its cladding provides an energy level of 1 MeV or less. The intensity of neutron capture thus changes significantly at any water-metal interface. Comparative analysis of adjacent gamma detectors senses changes from the normal condition with liquid coolant present to advise of changes in the presence and/or density of the coolant at these specific regions. The gamma detectors can also sense fission-product gas accumulation at the reactor head to advise of a failure of fuel-pin cladding.
DeVolpi, Alexander (Bolingbrook, IL)
Designing visual displays and system models for safe reactor operations
The material presented in this paper is based on two studies involving the design of visual displays and the user`s prospective model of a system. The studies involve a methodology known as Neuro-Linguistic Programming and its use in expanding design choices from the operator`s perspective image. The contents of this paper focuses on the studies and how they are applicable to the safety of operating reactors.
Brown-VanHoozer, S.A.
Brayton rotating units for space reactor power systems
Designs and analyses models of centrifugal-flow compressor and radial-inflow turbine of 40.8kWe Brayton Rotating Units (BRUs) are developed for 15 and 40g\\/mole He¢Xe working fluids. Also presented are the performance results of a space power system with segmented, gas cooled fission reactor heat source and three Closed Brayton Cycle loops, each with a separate BRU. The calculated performance parameters of
Bruno M. Gallo; Mohamed S. El-Genk
A heatpipe-cooled fast reactor concept has been under development at Los Alamos National Laboratory for the past several years, to be used as a power source for nuclear electric propulsion (NEP) or as a planetary surface power system. The reactor core consists of an array of modules that are held together by a core lateral restraint system. Each module comprises a single heatpipe surrounded by 3-6 clad fuel pins. As part of the design development and performance assessment activities for these reactors, specialized methods and models have been developed to perform thermal and stress analyses of the core modules. The methods have been automated so that trade studies can be readily performed, looking at design options such as module size, heatpipe and clad thickness, use of sleeves to contain the fuel, material type, etc. This paper describes the methods and models that have been developed, and presents thermal and stress analysis results for a Mars surface power system and a NEP power source.
Kapernick, R. J. (Richard J.); Guffee, R. M. (Ray M.)
Biological treatment of dye wastewaters using an anaerobic-oxic system.
Three dye solutions, namely, C.I. Acid Yellow 17, C.I. Basic Blue 3, and C.I. Basic Red 2, were treated in an upflow anaerobic sludge blanket (UASB) reactor followed by a semi-continuous aerobic activated sludge tank. When hydraulic retention time was about 12 hours, no significant color removal was observed in the aerobic stage. In the anaerobic stage, Acid Yellow 17, Basic Blue 3, and Basic Red 2 were removed by 20%, 72%, and 78%, respectively. To treat wastewater from a dye manufacturing factor with COD concentration of 1200 mg/l and Color of 500 degrees (dilution factor), an UASB reactor (4.5 liters) and an activated sludge tank (5 liters, adjustable), COD and color were removed by more than 83% and 90% at a COD loading rate of 5.3 kg COD/m3-day in the anaerobic stage, and at the hydraulic retention time of 6-10 hours for the anaerobic stage and 6.5 for the aerobic stage. The anaerobic stage of the A/O system removes both color and COD. In addition, it also improves biodegradability of dyes for further aeroic treatment. PMID:8976059
An, H; Qian, Y; Gu, X; Tang, W Z
Approach to developing reliable space reactor power systems
During Phase II, the Engineering Development Phase, the SP-100 Project has defined and is pursuing a new approach to developing reliable power systems. The approach to developing such a system during the early technology phase is described along with some preliminary examples to help explain the approach. Developing reliable components to meet space reactor power system requirements is based on a top-down systems approach which includes a point design based on a detailed technical specification of a 100-kW power system. The SP-100 system requirements implicitly recognize the challenge of achieving a high system reliability for a ten-year lifetime, while at the same time using technologies that require very significant development efforts. A low-cost method for assessing reliability, based on an understanding of fundamental failure mechanisms and design margins for specific failure mechanisms, is being developed as part of the SP-100 Program.
Mondt, Jack F.; Shinbrot, Charles H.
Safety characteristics of a suspended-pellet fission reactor system
A new fission reactor system with passive safety characteristics to eliminate the occurrence of loss-of-coolant accidents, reduce reactivity excursion effects, and which also provides for closure of the nuclear fuel cycle through on-site spent fuel management is examined. The concept uses multi-coated fuel pellets which are suspended by an upward moving coolant in vertical columns of the reactor core and electro-refining elemental separation to remove selected fission products prior to actinide recycling. The possibility of fuel melt following a loss-of-coolant is avoided as a decrease in coolant flow results in the removal of fuel from the core through the action of gravity alone. Average fluid velocities in the columns which are necessary to suspend the pellets are calculated and found to be consistent with the necessary heat extraction to yield ś1--10 Wth per column. The total output power of such suspended pellet-type reactors is compared to the power necessary to provide the suspending fluid flow, yielding favourable ratios of ś102--103. The reduction of reactivity excursion tendencies is envisaged through an ablative layer of material in the pellets which sublimates at temperatures above normal operating conditions. In the event of a power or temperature increase the particles fragment and thereby change their hydrodynamic drag characteristics, thus leading to fuel removal from the core by elutriation. Comparison of nuclear-to-thermal response times and elutriation rates for limiting power transients indicate that the present design assists in reactivity excursion mitigation. Closure of the nuclear fuel cycle is attained through a spent fuel management strategy which requires only on-site storage of a fraction of the fission products produced during reactor operation. Electro-refining separation of selected fission products combined with complete actinide recycling yields no isolation of plutonium or highly enriched uranium during the procedure. The out-of-core waste stream has a significantly reduced radioactivity, volume and lifetime compared to the once-through waste management strategy and thus provides an alternative to long-term geological disposal of fission reactor wastes. The Pellet Suspension Reactor concept possesses some unique operating characteristics and, additionally, is shown to be similar to conventional fission reactors in terms of common performance features.
Kingdon, David Ross
Spouted Bed Reactor Monitoring System for Particulate Nuclear Fuel.
Conversion and coating of particle nuclear fuel is performed in spouted (fluidized) bed reactors. The reactor must be capable of operating at temperatures up to 2000 degrees C in inert, flammable, and coating gas environments. The spouted bed reactor geom...
D. S. Wendt R. L. Bewley W. E. Windes
Substrate removal kinetics in an upflow anaerobic sludge blanket reactor decolorising simulated textile wastewater
A simulated wastewater containing sizing agents, azo dyes, salts and other additives was treated using a lab-scale upflow anaerobic sludge blanket (UASB) reactor at different hydraulic retention times (HRT) in order to obtain the substrate removal kinetic of the reactor through decolorization of dyes. COD removal efficiencies decreased from 80 to 29.5% when the HRT decreased from 100 to 6h.
Mustafa I?ik; Delia Teresa Sponza
Fossil-Fuel Processing Technical/Professional Services: Comparison of Fischer-Tropsch Reactor Systems. Phase I, Final Report.
The Fischer-Tropsch reaction was commercialized in Germany and used to produce military fuels in fixed bed reactors. It was recognized from the start that this reactor system had severe operating and yield limitations and alternative reactor systems were ...
A. G. Vickers G. J. Thompson M. L. Riekena
77 FR 62270 - Proposed Revision Treatment of Non-Safety Systems for Passive Advanced Light Water Reactors
...Non-Safety Systems for Passive Advanced Light Water Reactors AGENCY: Nuclear Regulatory...Systems (RTNSS) for Passive Advanced Light Water Reactors.'' The current SRP does...the proposed RTNSS for Passive Advance Light Water Reactors. DATES: Submit...
A Computer Program Predicting Steady-State Performance of a Nuclear Research Reactor's Cooling System
The performances of a nuclear reactor are directly affected by its cooling system, especially when it uses wet towers to evacuate the heat generated in the nuclear reactor core. Failure of the cooling system can yield very serious damages to most of the components of the nuclear reactor core. In this work, a computer program simulating the thermal behavior of
Sidi Ali; Kamel
77 FR 55877 - Initial Test Program of Condensate and Feedwater Systems for Light-Water Reactors
...of Condensate and Feedwater Systems for Light-Water Reactors AGENCY: Nuclear Regulatory...condensate and feedwater systems in all types of light water reactor facilities; and (2) to...including condensate storage and supply, for light-water reactors (LWRs) and for...
Autonomous Control Capabilities for Space Reactor Power Systems
The National Aeronautics and Space Administration's (NASA's) Project Prometheus, the Nuclear Systems Program, is investigating a possible Jupiter Icy Moons Orbiter (JIMO) mission, which would conduct in-depth studies of three of the moons of Jupiter by using a space reactor power system (SRPS) to provide energy for propulsion and spacecraft power for more than a decade. Terrestrial nuclear power plants rely upon varying degrees of direct human control and interaction for operations and maintenance over a forty to sixty year lifetime. In contrast, an SRPS is intended to provide continuous, remote, unattended operation for up to fifteen years with no maintenance. Uncertainties, rare events, degradation, and communications delays with Earth are challenges that SRPS control must accommodate. Autonomous control is needed to address these challenges and optimize the reactor control design. In this paper, we describe an autonomous control concept for generic SRPS designs. The formulation of an autonomous control concept, which includes identification of high-level functional requirements and generation of a research and development plan for enabling technologies, is among the technical activities that are being conducted under the U.S. Department of Energy's Space Reactor Technology Program in support of the NASA's Project Prometheus. The findings from this program are intended to contribute to the successful realization of the JIMO mission.
Wood, Richard T.; Neal, John S.; Brittain, C. Ray; Mullens, James A.
Ongoing Development of a Series Bosch Reactor System
Future manned missions to deep space or planetary surfaces will undoubtedly incorporate highly robust, efficient, and regenerable life support systems that require minimal consumables. To meet this requirement, NASA continues to explore a Bosch-based carbon dioxide reduction system to recover oxygen from CO2. In order to improve the equivalent system mass of Bosch systems, we seek to design and test a "Series Bosch" system in which two reactors in series are optimized for the two steps of the reaction, as well as to explore the use of in situ materials as carbon deposition catalysts. Here we report recent developments in this effort including assembly and initial testing of a Reverse Water-Gas Shift reactor (RWGSr) and initial testing of two gas separation membranes. The RWGSr was sized to reduce CO2 produced by a crew of four to carbon monoxide as the first stage in a Series Bosch system. The gas separation membranes, necessary to recycle unreacted hydrogen and CO2, were similarly sized. Additionally, we report results of preliminary experiments designed to determine the catalytic properties of Martian regolith simulant for the carbon formation step.
Abney, Morgan B; Mansell, J. Matthew; Stanley, Christine; Edmunson, Jennifer; DuMez, Samuel J.; Chen, Kevin
Future manned missions to deep space or planetary surfaces will undoubtedly require highly robust, efficient, and regenerable life support systems that require minimal consumables. To meet this requirement, NASA continues to explore a Bosch-based carbon dioxide reduction system to recover oxygen from CO2. In order to improve the equivalent system mass of Bosch systems, we seek to design and test a "Series Bosch" system in which two reactors in series are optimized for the two steps of the reaction, as well as to explore the use of in situ materials as carbon deposition catalysts. Here we report recent developments in this effort including assembly and initial testing of a Reverse Water-Gas Shift reactor (RWGSr) and initial testing of two gas separation membranes. The RWGSr was sized to reduce CO2 produced by a crew of four to carbon monoxide as the first stage in a Series Bosch system. The gas separation membranes, necessary to recycle unreacted hydrogen and CO2, were similarly sized. Additionally, we report results of preliminary experiments designed to determine the catalytic properties of Martian and Lunar regolith simulant for the carbon deposition step.
Abney, Morgan; Mansell, Matt; DuMez, Sam; Thomas, John; Cooper, Charlie; Long, David
A Novel Approach to Material Development for Advanced Reactor Systems
OAK B188 A Novel Approach to Material Development for Advanced Reactor Systems. Year one of this project had three major goals. First, to specify, order and install a new high current ion source for more rapid and stable proton irradiation. Second, to assess the use of low temperature irradiation and chromium pre-enrichment in an effort to isolate a radiation damage microstructure in stainless steel without the effects of RIS. Third, to initiate irradiation of reactor pressure vessel steel and Zircaloy. In year 1 quarter 3, the project goal was to complete irradiation of model alloys of RPV steels for a range of doses and begin sample characterization. We also planned to prepare samples for microstructure isolation in stainless steels, and to identify sources of Zircaloy for irradiation and characterization.
Was, G.S.; Atzmon, M.; Wang, L.
System for fuel rod removal from a reactor module
A robotic system for remote underwater withdrawal of the fuel rods from fuel modules of a light water breeder reactor includes a collet/grapple assembly for gripping and removing fuel rods in each module, which is positioned by use of a winch and a radial support means attached to a vertical support tube which is mounted over the fuel module. A programmable logic controller in conjunction with a microcomputer, provides control for the accurate positioning and pulling force of the rod grapple assembly. Closed circuit television cameras are provided which aid in operator interface with the robotic system. 7 figs.
Matchett, R.L.; Fodor, G.; Kikta, T.J.; Bacvinsicas, W.S.; Roof, D.R.; Nilsen, R.J.; Wilczynski, R.
A robotic system for remote underwater withdrawal of the fuel rods from fuel modules of a light water breeder reactor includes a collet/grapple assembly for gripping and removing fuel rods in each module, which is positioned by use of a winch and a radial support means attached to a vertical support tube which is mounted over the fuel module. A programmable logic controller in conjunction with a microcomputer, provides control for the accurate positioning and pulling force of the rod grapple assembly. Closed circuit television cameras are provided which aid in operator interface with the robotic system.
Matchett, Richard L. (Bethel Park, PA); Roof, David R. (North Huntingdon, PA); Kikta, Thomas J. (Pittsburgh, PA); Wilczynski, Rosemarie (McKees Rocks, PA); Nilsen, Roy J. (Pittsburgh, PA); Bacvinskas, William S. (Bethel Park, PA); Fodor, George (Pittsburgh, PA)
Optimization of biogas production from wheat straw stillage in UASB reactor
In the present study, thermophilic anaerobic digestion of wheat straw stillage was investigated. Methane potential of stillage was determined in batch experiments at two different substrate concentrations. Results showed that higher methane yields of 324ml\\/g-(volatile solids) VSadded were obtained at stillage concentrations of 12.8g-VS\\/L than at 25.6g-VS\\/l. Continuous anaerobic digestion of stillage was performed in an up-flow anaerobic sludge blanket
Prasad Kaparaju; MarĒa Serrano; Irini Angelidaki
Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates
This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes.
Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S
Nuclear plant-aging research on reactor protection systems
This report presents the rsults of a review of the Reactor Trip System (RTS) and the Engineered Safety Feature Actuating System (ESFAS) operating experiences reported in Licensee Event Reports (LER)s, the Nuclear Power Experience data base, Nuclear Plant Reliability Data System, and plant maintenance records. Our purpose is to evaluate the potential significance of aging, including cycling, trips, and testing as contributors to degradation of the RTS and ESFAS. Tables are presented that show the percentage of events for RTS and ESFAS classified by cause, components, and subcomponents for each of the Nuclear Steam Supply System vendors. A representative Babcock and Wilcox plant was selected for detailed study. The US Nuclear Regulatory Commission's Nuclear Plant Aging Research guidelines were followed in performing the detailed study that identified materials susceptible to aging, stressors, environmental factors, and failure modes for the RTS and ESFAS as generic instrumentation and control systems. Functional indicators of degradation are listed, testing requirements evaluated, and regulatory issues discussed.
Meyer, L.C.
Water gas shift membrane reactor for CO 2 control in IGCC systems: techno-economic feasibility study
A novel reactor concept, the water gas shift membrane reactor (WGS-MR) for CO2 removal in IGCC systems has been investigated. In order to establish full insight in the possibilities of the application of such a reactor, a multidisciplinary feasibility study has been carried out comprising system integration studies, catalyst research, membrane research, membrane reactor modelling and bench scale membrane reactor
M Bracht; P. T Alderliesten; R Kloster; R Pruschek; G Haupt; E Xue; J. R. H Ross; M. K Koukou; N Papayannakos
Instrument accuracy in reactor vessel inventory tracking systems
Instrumentation needs for detection of inadequate core cooling. Studies of the Three Mile Island accident identified the need for additional instrumentation to detect inadequate core cooling (ICC) in nuclear power plants. Industry studies by plant owners and reactor vendors supported the conclusion that improvements were needed to help operators diagnose the approach to or existence of ICC as well as to provide more complete information for operator control of safety injection flow to minimize the consequences of such an accident. In 1980, the US Nuclear Regulatory Commission (NRC) required further studies by the industry and described ICC instrumentation design requirements that included human factors and environmental considerations. On December 10, 1982, NRC issued to Babcock and Wilcox (B and W) licensees orders for Modification of License and transmitted to pressurized water reactor licensees Generic Letter 82-28 to inform them of the revised NRC requirements. The instrumentation requirements include upgraded subcooling margin monitors (SMM), upgraded core exit thermocouples (CET), and installation of a reactor coolant inventory tracking system. NRC Regulatory Guide 1.97, which covers accident monitoring instrumentation, was revised (Rev. 3) to be consistent with the requirements of item II.F.2 of NUREG-0737.
Anderson, J.L.; Anderson, R.L.; Morelock, T.C.; Hauang, T.L.; Phillips, L.E.
Modeling the performance of ōup-flow anaerobic sludge blanketö reactor based wastewater treatment plant using linear and nonlinear approachesŚA case study
The paper describes linear and nonlinear modeling of the wastewater data for the performance evaluation of an up-flow anaerobic sludge blanket (UASB) reactor based wastewater treatment plant (WWTP). Partial least squares regression (PLSR), multivariate polynomial regression (MPR) and artificial neural networks (ANNs) modeling methods were applied to predict the levels of biochemical oxygen demand (BOD) and chemical oxygen demand (COD)
Kunwar P. Singh; Nikita Basant; Amrita Malik; Gunja Jain
Comparing the performance of UASB and GRABBR treating low strength wastewaters
Anaerobic technologies have proved successful in the treatment of various high strength wastewaters with perceptible advantages over aerobic systems. The applicability of anaerobic processes to treat low strength wastewaters has been increasing with the evolution of high-rate reactors capable of achieving high sludge retention time (SRT) when operating at low HRT. However, the performance of these systems can be affected
A. S. Shanmugam; J. C. Akunna
Aging study of boiling water reactor high pressure injection systems
The purpose of high pressure injection systems is to maintain an adequate coolant level in reactor pressure vessels, so that the fuel cladding temperature does not exceed 1,200{degrees}C (2,200{degrees}F), and to permit plant shutdown during a variety of design basis loss-of-coolant accidents. This report presents the results of a study on aging performed for high pressure injection systems of boiling water reactor plants in the United States. The purpose of the study was to identify and evaluate the effects of aging and the effectiveness of testing and maintenance in detecting and mitigating aging degradation. Guidelines from the United States Nuclear Regulatory Commission`s Nuclear Plant Aging Research Program were used in performing the aging study. Review and analysis of the failures reported in databases such as Nuclear Power Experience, Licensee Event Reports, and the Nuclear Plant Reliability Data System, along with plant-specific maintenance records databases, are included in this report to provide the information required to identify aging stressors, failure modes, and failure causes. Several probabilistic risk assessments were reviewed to identify risk-significant components in high pressure injection systems. Testing, maintenance, specific safety issues, and codes and standards are also discussed.
Conley, D.A.; Edson, J.L.; Fineman, C.F. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)
Mekanismer af betydning for dannelse af granula i UASB-reaktorer. (Mechanisms of importance for the formation of granules in an UASB reactors).
Thermophilic granules exhibiting good stabilities were successfully developed on glucose, acetate, and a mixture of acetate, propionate, and butyrate. The only genus of aceticlastic methanogens identified in the granules were Methanosarcina spp. An examin...
M. Winther-Nielsen
Reactor flooding system for a retaining molten core materials in a reactor vessel by the improved external vessel cooling capability
A reactor cavity flooding system, which is used to immerse the hemispherical lower head of a nuclear reactor vessel by flooding the reactor cavity, is connected to both coolant injection nozzles located at the annulus gap between the lower head and the thermal insulator of a reactor and the discharge loops which are used to drain the hot water of the annulus gap into either the cavity floor or a liquid eductor. The subcooled water at a fire protection system can be directly injected into the annulus gap through twenty-five (25) nozzles at the lowest, middle, and top injection headers by a pump. The hot water heated at the lower head will be drained into either the cavity floor and/or the liquid eductor via two discharge loops that consist of both a suction header in the annulus gap at the equator level of the lower head and four (4) leakage collectors at the outside of four (4) shear keys of a reactor vessel. Drainage and recirculation of the hot water can be achieved in two ways. The first way uses the pump for injecting the subcooled water and for recirculating the drained water in a reactor cavity. The second way uses a liquid eductor for draining the hot water, instead of discharging it into the reactor cavity floor, and a pump for recirculating the drained water blended with subcooled water through the liquid eductor.
Technological implications of SNAP reactor power system development on future space nuclear power systems
Nuclear reactor systems are one method of satisfying space mission power needs. The development of such systems must proceed on a path consistent with mission needs and schedules. This path, or technology roadmap, starts from the power system technology data base available today. Much of this data base was established during the 1960s and early 1970s, when government and industry developed space nuclear reactor systems for steady-state power and propulsion. One of the largest development programs was the Systems for Nuclear Auxiliary Power (SNAP) Program. By the early 1970s, a technology base had evolved from this program at the system, subsystem, and component levels. There are many implications of this technology base on future reactor power systems. A review of this base highlights the need for performing a power system technology and mission overview study. Such a study is currently being performed by Rockwell's Energy Systems Group for the Department of Energy and will assess power system capabilities versus mission needs, considering development, schedule, and cost implications. The end product of the study will be a technology roadmap to guide reactor power system development.
Anderson, R.V.
Fast Reactor with Indirect Cycle System of Supercritical COŌ Gas Turbine Plant
An attractive power generation system using supercritical carbon dioxide (C0Ō) gas turbine┬╣ has been studied because of high cycle thermal efficiency and potential compactness of the Balance Of Plant equipment due to the small-sized turbo machinery system. This paper deals with an indirect cycle system with a sodium-cooled reactor eliminating intermediate cooling system, and design study of reactor core, reactor
Mito Makoto; Yoshioka Naoki; Ohkubo Yoshiyuki; Tsuzuki Nobuyoshi; Kato Yasuyoshi
Extension of the CENTAR system simulation code to thermionic space nuclear reactors
The Code for Extended Nonlinear Transient Analysis of Extraterrestial Reactors (CENTAR) is a general-purpose reactor system simulation code capable of modeling coupled heat transfer, fluid flow, neutronic, and control in an arbitrary reactor system (or subsystem) configuration. CENTAR 4.0 has been enhanced to support thermionic solid-core systems as well as liquid-metal systems. Several new models have been added. The fuel
Bahram Nassersharif; Michael J. Gaeta; Francoise Berge; Laura Guffee; Ken Williams
A long term radiological risk model for plutonium-fueled and fission reactor space nuclear system
This report describes the optimization of the RISK III mathematical model, which provides risk assessment for the use of a plutonium-fueled, fission reactor in space systems. The report discusses possible scenarios leading to radiation releases on the ground; distinctions are made for an intact reactor and a dispersed reactor. Also included are projected dose equivalents for various accident situations.
Bartram, B. W.; Dougherty, D. K.
Reactor/Brayton power systems for nuclear electric spacecraft
Studies are currently underway to assess the technological feasibility of a nuclear-reactor-powered spacecraft propelled by electric thrusters. This vehicle would be capable of performing detailed exploration of the outer planets of the solar system during the remainder of this century. The purpose of this study was to provide comparative information on a closed cycle gas turbine power conversion system. The results have shown that the performance is very competitive and that a 400 kWe space power system is dimensionally compatible with a single Space Shuttle launch. Performance parameters of system mass and radiator area were determined for systems from 100 to 1000 kWe. A 400 kWe reference system received primary attention. The components of this system were defined and a conceptual layout was developed with encouraging results. The preliminary mass determination for the complete power system was very close to the desired goal of 20 kg/kWe. Use of more advanced technology (higher turbine inlet temperature) will substantially improve system performance characteristics.
Layton, J. P.
Coil system for a mirror-based hybrid reactor
Two different superconducting coil systems for the SFLM Hybrid study - a quadrupolar mirror based fusion-fission reactor study - are presented. One coil system is for a magnetic field with 2 T at the midplane and a mirror ratio of four. This coil set consists of semiplanar coils in two layers. The alternative coil system is for a downscaled magnetic field of 1.25 T at the midplane and a mirror ratio of four, where a higher {beta} is required to achieve sufficient the neutron production. This coil set has one layer of twisted 3D coils. The 3D coils are expected to be considerably cheaper than the semiplanar, since NbTi superconductors can be used for most coils instead of Nb3Sn due to the lower magnetic field.
Hagnestal, A.; Agren, O.; Moiseenko, V. E. [Uppsala University, Angstroem laboratory, Division of Electricity, Box 534, SE-751 21 Uppsala (Sweden); Institute of Plasma Physics, National Science Center 'Kharkov Institute of Physics and Technology', Akademichna st. 1, 61108 Kharkiv (Ukraine)
Reliability analysis of Safety Logic with Fine Impulse Test system of Indian Prototype Fast Breeder Reactor
Safety Logic (SL) System is a safety critical system provided to protect the Prototype Fast Breeder Reactor (PFBR) against various neutronic & thermal incidents. SL system receives trip parameters from various systems such as neutron flux monitoring, failed fuel detection, sodium flow monitoring, reactor inlet temperature monitoring etc and performs logical operations to drive Electro Magnet (EM) coils of Control
M. K. Misra; N. Sridhar; B. Krishnakumar; S. A. V. S. Murty; P. Swaminathan
Nuclear reactor cooling system decontamination reagent regeneration. [PWR; BWR
An improved method for decontaminating the coolant system of water-cooled nuclear power reactors and for regenerating the decontamination solution is described. A small amount of one or more weak-acid organic complexing agents is added to the reactor coolant, and the pH is adjusted to form a decontamination solution which is circulated throughout the coolant system to dissolve metal oxides from the interior surfaces and complex the resulting metal ions and radionuclide ions. The coolant containing the complexed metal ions and radionuclide ions is passed through a strong-base anion exchange resin bed which has been presaturated with a solution containing the complexing agents in the same ratio and having the same pH as the decontamination solution. As the decontamination solution passes through the resin bed, metal-complexed anions are exchanged for the metal-ion-free anions on the bed, while metal-ion-free anions in the solution pass through the bed, thus removing the metal ions and regenerating the decontamination solution.
Anstine, L.D.; James, D.B.; Melaika, E.A.; Peterson, J.P. Jr.
Expert system driven fuzzy control application to power reactors
For the purpose of nonlinear control and uncertainty/imprecision handling, fuzzy controllers have recently reached acclaim and increasing commercial application. The fuzzy control algorithms often require a ``supervisory`` routine that provides necessary heuristics for interface, adaptation, mode selection and other implementation issues. Performance characteristics of an on-line fuzzy controller depend strictly on the ability of such supervisory routines to manipulate the fuzzy control algorithm and enhance its control capabilities. This paper describes an expert system driven fuzzy control design application to nuclear reactor control, for the automated start-up control of the Experimental Breeder Reactor-II. The methodology is verified through computer simulations using a valid nonlinear model. The necessary heuristic decisions are identified that are vitally important for the implemention of fuzzy control in the actual plant. An expert system structure incorporating the necessary supervisory routines is discussed. The discussion also includes the possibility of synthesizing the fuzzy, exact and combined reasoning to include both inexact concepts, uncertainty and fuzziness, within the same environment.
Tsoukalas, L.H.; Berkan, R.C.; Upadhyaya, B.R.; Uhrig, R.E.
High Flux Isotope Reactor system RELAP5 input model
A thermal-hydraulic computational model of the High Flux Isotope Reactor (HFIR) has been developed using the RELAP5 program. The purpose of the model is to provide a state-of-the art thermal-hydraulic simulation tool for analyzing selected hypothetical accident scenarios for a revised HFIR Safety Analysis Report (SAR). The model includes (1) a detailed representation of the reactor core and other vessel components, (2) three heat exchanger/pump cells, (3) pressurizing pumps and letdown valves, and (4) secondary coolant system (with less detail than the primary system). Data from HFIR operation, component tests, tests in facility mockups and the HFIR, HFIR specific experiments, and other pertinent experiments performed independent of HFIR were used to construct the model and validate it to the extent permitted by the data. The detailed version of the model has been used to simulate loss-of-coolant accidents (LOCAs), while the abbreviated version has been developed for the operational transients that allow use of a less detailed nodalization. Analysis of station blackout with core long-term decay heat removal via natural convection has been performed using the core and vessel portions of the detailed model.
Morris, D.G.; Wendel, M.W.
The MAUS nuclear space reactor with ion propulsion system
MAUS (Moltiplicatore Avanzato Ultracompatto Spaziale) is a nuclear reactor concept design capable to ensure a reliable, long-lasting, low-mass, compact energy supply needed for advanced, future space missions. The exploration of the solar system and the space beyond requires the development of nuclear energy generators for supplying electricity to space-bases, spacecrafts, probes or satellites, as well as for propelling ships in long space missions. For propulsion, the MAUS nuclear reactor could be used to power electric ion drive engines. An ion engine is able to build up to very high velocities, far greater than chemical propulsion systems, but has high power and long service requirements. The MAUS concept is described, together with the ion propulsion engine and together with the reference thermoionic process used to convert the thermal power into electricity. The design work has been performed at the Nuclear Engineering and Energy Conversion Department of the University of Rome "La Sapienza" starting from 1992 on an issue submitted by the Italian Space Agency (ASI), in cooperation with the research laboratories of ENEA.
Mainardi, Enrico
Effects of directly soluble and fibrous rapidly acidifying chemical oxygen demand and reactor liquid surface tension on granulation and sludge-bed stability in upflow anaerobic sludge-blanket reactors
In recent years, it has become clear that the rapidly acidifying chemical oxygen demand (RACOD) content of the waste water\\u000a and the surface tension of the reactor liquid contribute to the phenomenon of granular growth in upflow anaerobic sludge-blanket\\u000a reactors (UASB). By adding 20% of directly soluble RACOD, in the form of a sucrose\\/starch mixture, on top of the original
H. Grootaerd; B. Liessens; W. Verstraete
Fossil-fuel processing technical\\/professional services: comparison of Fischer-Tropsch reactor systems. Phase I, final report
The Fischer-Tropsch reaction was commercialized in Germany and used to produce military fuels in fixed bed reactors. It was recognized from the start that this reactor system had severe operating and yield limitations and alternative reactor systems were sought. In 1955 the Sasol I complex, using an entrained bed (Synthol) reactor system, was started up in South Africa. Although this
G. J. Thompson; M. L. Riekena; A. G. Vickers
High rate performance and characterization of granular methanogenic sludges in upflow anaerobic sludge blanket reactors fed with various defined substrates
High rate granular methanogenic fermentations were performed in one-phase upflow anaerobic sludge blanket (UASB) reactors treating synthetic wastewaters containing starch, sucrose, ethanol, and butyrate plus propionate. All granules formed showed high settling velocities which enabled high cell mass retention and accommodation of high loading rates. The maximum COD removal rates (g COD\\/l-reactorĘd) obtained after 500-d operations were 7.6 for starch,
Satoshi Fukuzaki; Naomichi Nishio; Shiro Nagai
Organic loading rate and food-to-microorganism ratio shape prokaryotic diversity in a demo-scale up-flow anaerobic sludge blanket reactor treating domestic wastewater.
We investigated the microbial community in an up-flow anaerobic sludge blanket (UASB) reactor treating domestic wastewater (DW) during two different periods of organic loading rate (OLR) and food-to-microorganism (F/M) ratio. 16S rDNA clone libraries were generated, and quantitative real-time PCR (qPCR) analyses were performed. Fluctuations in the OLR and F/M ratio affected the abundance and the composition of the UASB prokaryotic community, mainly at the species level, as well as the performance of the UASB reactor. The qPCR analysis suggested that there was a decrease in the bacterial cell number during the rainy season, when the OLR and F/M ratio were lower. However, the bacterial diversity was higher during this time, suggesting that the community degraded more diversified substrates. The diversity and the abundance of the archaeal community were higher when the F/M ratio was lower. Shifts in the methanogenic community composition might have influenced the route of methane production, with methane produced by acetotrophic methanogens (dry season), and by hydrogenotrophic, methylotrophic and acetotrophic methanogens (rainy season). This study revealed higher levels of bacterial diversity, metabolic specialization and chemical oxygen demand removal efficiency of the DW UASB reactor during the rainy season. PMID:24000090
Cardinali-Rezende, Juliana; Ara·jo, Juliana C; Almeida, Paulo G S; Chernicharo, Carlos A L; Sanz, Josķ L; Chartone-Souza, Edmar; Nascimento, Andrķa M A
A period detection instrument for nuclear reactor safety systems
A reactor-peried detection instrument featuring a high degree of freedom ; from scrams due to spurious signals has been designed, constructed, and tested. ; The technique employed is suitable for critical facilities and power reactors. ; Voltage level changes V(t) from a logarithmic amplifier are utilized to determine ; reactor period when signal levels are small, and both voltage level
G. K. Rusch; W. P. McDowell
Analysis and numerical optimization of gas turbine space power systems with nuclear fission reactor heat sources
A new three objective optimization technique is developed and applied to find the operating conditions for fission reactor heated Closed Cycle Gas Turbine (CCGT) space power systems at which maximum efficiency, minimum radiator area, and minimum total system mass is achieved. Such CCGT space power systems incorporate a nuclear reactor heat source with its radiation shield; the rotating turbo-alternator, consisting
Albert J. Juhasz
Reactor and Nuclear Systems Division Status Report on Modeling Reactor Economics.
The recent interest in Small Modular Reactors (SMRs) from industry within the United States and around the world has spurred discussion on the benefits of the SMR versus the larger, central-station power reactor. The main thrust of this discussion on thos...
R. E. Hale R. J. Moses T. J. Harrison
RVACS/RACS (reactor vessel auxiliary cooling system/reactor air cooling system) shutdown heat removal in a modular sized LMR (liquid metal reactor)
Shutdown heat removal by a RVACS for an unprotected loss of flow case in a modular sized LMR has been analyzed with the SASSYS-1 LMR systems analysis code. For this case it was assumed that all power was lost to the primary and intermediate sodium pumps, and feedwater flow to the steam generators was lost. The control rods failed to scram, but reactivity feedback shut down the power to decay heat levels. The only heat removal was by sodium natural circulation from the core to the vessel wall and by cooling of the vessel wall by radiation and air natural circulation in the Reactor Air Cooling System. The case was run until the system temperatures peaked when the decay heat power level dropped below the heat removal rate.
Dunn, F.E.; Wigeland, R.A.; Lo, R.K.
Nuclear safety as applied to space power reactor systems
Current space nuclear power reactor safety issues are discussed with respect to the unique characteristics of these reactors. An approach to achieving adequate safety and a perception of safety is outlined. This approach calls for a carefully conceived safety program which makes uses of lessons learned from previous terrestrial power reactor development programs. This approach includes use of risk analyses, passive safety design features, and analyses/experiments to understand and control off-design conditions. The point is made that some recent accidents concerning terrestrial power reactors do not imply that space power reactors cannot be operated safety.
Cummings, G.E.
Completely modular thermionic reactor ion propulsion system /trips/.
Description of a nuclear reactor powered ion propulsion system which is an advanced completely modularized system lending itself to development of prototype and/or flight type components without the need for complete system tests until late in the development program. This modularity is achieved in all of the subsystems and components of the electric propulsion system, including the thermionic fuel elements, the heat rejection subsystem (head pipes), the power conditioning modules, and the ion thrusters. The use of heat pipes for cooling the collectors and as a means of heat transport to the radiator allows early prototype or flight configuration testing of a small module of the heat rejection subsystem as opposed to full scale liquid metal pumps and radiators in a large vacuum chamber. The power conditioner (p/c) is arranged in modules with passive cooling which allows complete prototype testing. The ion engines are typically matched with one or more p/c modules and are the same size for any power level propulsion system of interest.
Compatibility of refractory materials for nuclear reactor poison control systems
Metal-clad poison rods have been considered for the control system of an advanced space power reactor concept studied at the NASA Lewis Research Center. Such control rods may be required to operate at temperatures of about 140O C. Selected poison materials (including boron carbide and the diborides of zirconium, hafnium, and tantalum) were subjected to 1000-hour screening tests in contact with candidate refractory metal cladding materials (including tungsten and alloys of tantalum, niobium, and molybdenum) to assess the compatibility of these materials combinations at the temperatures of interest. Zirconium and hafnium diborides were compatible with refractory metals at 1400 C, but boron carbide and tantalum diboride reacted with the refractory metals at this temperature. Zirconium diboride also showed promise as a reaction barrier between boron carbide and tungsten.
Sinclair, J. H.
Reactor protection system design using application specific integrated circuits
Implementing reactor protection systems (RPS) or other engineering safeguard systems with application specific integrated circuits (ASICs) offers significant advantages over conventional analog or software based RPSs. Conventional analog RPSs suffer from setpoints drifts and large numbers of discrete analog electronics, hardware logic, and relays which reduce reliability because of the large number of potential failures of components or interconnections. To resolve problems associated with conventional discrete RPSs and proposed software based RPS systems, a hybrid analog and digital RPS system implemented with custom ASICs is proposed. The actual design of the ASIC RPS resembles a software based RPS but the programmable software portion of each channel is implemented in a fixed digital logic design including any input variable computations. Set point drifts are zero as in proposed software systems, but the verification and validation of the computations is made easier since the computational logic an be exhaustively tested. The functionality is assured fixed because there can be no future changes to the ASIC without redesign and fabrication. Subtle error conditions caused by out of order evaluation or time dependent evaluation of system variables against protection criteria are eliminated by implementing all evaluation computations in parallel for simultaneous results. On- chip redundancy within each RPS channel and continuous self-testing of all channels provided enhanced assurance that a particular channel is available and faults are identified as soon as possible for corrective actions. The use of highly integrated ASICs to implement channel electronics rather than the use of discrete electronics greatly reduces the total number of components and interconnections in the RPS to further increase system reliability. A prototype ASIC RPS channel design and the design environment used for ASIC RPS systems design is discussed.
Battle, R.E.; Bryan, W.L.; Kisner, R.A.; Wilson, T.L. Jr.
IAEA coordinated research activities on materials for advanced reactor systems
After the recent accident at the Fukushima Daiichi Nuclear Power Plant, public resentment towards nuclear energy is very high; however it is also important to emphasise that for other facilities the safety record has been remarkably good when compared to those of other new or conventional energy technologies. In addition to clear safety improvements new systems will have increased thermal efficiency, maximised fuel use, and reduced nuclear waste production. In order to initiate commercial deployment of power reactors, small scale demonstrations of such new systems are urgently needed. This will help to develop, test and qualify new structural materials with improved properties with respect to radiation, corrosion, thermal and other degradation processes. To solve all challenges related to the performance parameters of such materials, internationally driven efforts must focus on research, targeted testing, and final selection of appropriate materials. This is recognised as a key milestone in successful demonstration and future deployment of newly designed nuclear reactors. Because of clear synergies between fusion and fission research and development communities have been identified, closer cooperation of research groups has been stimulated. Although some operational conditions are expected to change, many basic features will remain similar. In addition to the material science effort, new experimental facilities are being developed for the study of high-radiation damage effects on the microstructure of candidate materials prior to their qualification. During last 5 years, the International Atomic Energy Agency (IAEA) launched several coordinated research activities in this specific, but very important field. This paper gives a summary of on-going IAEA activities related to the development and characterisation of structural and plasma facing materials for nuclear energy.
Zeman, A.; Inozemtsev, V.; Kamendje, R.; Beatty, R. L.
Design considerations for ITER (International Thermonuclear Experimental Reactor) magnet systems
The International Thermonuclear Experimental Reactor (ITER) is now completing a definition phase as a beginning of a three-year design effort. Preliminary parameters for the superconducting magnet system have been established to guide further and more detailed design work. Radiation tolerance of the superconductors and insulators has been of prime importance, since it sets requirements for the neutron-shield dimension and sensitively influences reactor size. The major levels of mechanical stress in the structure appear in the cases of the inboard legs of the toroidal-field (TF) coils. The cases of the poloidal-field (PF) coils must be made thin or segmented to minimize eddy current heating during inductive plasma operation. As a result, the winding packs of both the TF and PF coils includes significant fractions of steel. The TF winding pack provides support against in-plane separating loads but offers little support against out-of-plane loads, unless shear-bonding of the conductors can be maintained. The removal of heat due to nuclear and ac loads has not been a fundamental limit to design, but certainly has non-negligible economic consequences. We present here preliminary ITER magnetic systems design parameters taken from trade studies, designs, and analyses performed by the Home Teams of the four ITER participants, by the ITER Magnet Design Unit in Garching, and by other participants at workshops organized by the Magnet Design Unit. The work presented here reflects the efforts of many, but the responsibility for the opinions expressed is the authors'. 4 refs., 3 figs., 4 tabs.
Henning, C.D.; Miller, J.R.
Identification of seismic structures, systems and components of PHEC system of Fast Breeder Test Reactor
The reactor shutdown is followed by power decay and the decay heat removal is carried out by different decay heat removal (DHR) systems based on the plant configuration. In FBTR, normal mode of DHR is by the primary and secondary sodium loops and through steam generators (SG) with trap doors of the SG casing open. For DHR by normal mode,
S. Usha; C. Senthil Kumar; G. Srinivasan; P. C. Basu
Lunar electric power systems utilizing the SP100 reactor coupled to dynamic conversion systems
An integration study was performed by coupling an SP-100 reactor to either a Brayton or Stirling power conversion subsystem. The application was for a surface power system to supply power requirements to a lunar base. A power level of 550 kWe was selected based on the NASA Space Exploration Initiative 90-day study. Reliability studies were initially performed to determine optimum
Richard B. Harty; Richard E. Durand; Lee S. Mason
Gas Core Reactor-MHD Power System with Cascading Power Cycle
The US Department of Energy initiative Gen-IV aim is to produce an entire nuclear energy production system with next generation features for certification before 2030. A Generation 4 capable system must have superior sustainability, safety and reliability, and economic cost advantages in comparison with third generation light water reactors. A gas core reactor (GCR) with magnetohydrodynamic (MHD) power converter and
Blair M. Smith; Samim Anghaie; Travis W. Knight
Computer simulation of magnetization-controlled shunt reactors for calculating electromagnetic transients in power systems
A computer procedure for simulating magnetization-controlled dc shunt reactors is described, which enables the electromagnetic transients in electric power systems to be calculated. It is shown that, by taking technically simple measures in the control system, one can obtain high-speed reactors sufficient for many purposes, and dispense with the use of high-power devices for compensating higher harmonic components.
Karpov, A. S. [St Petersburg State Polytechnical University, JSC 'System Operator of the United Power System', Leningradskoe RDU (Russian Federation)] [St Petersburg State Polytechnical University, JSC 'System Operator of the United Power System', Leningradskoe RDU (Russian Federation)
Scram and Nonlinear Reactor System Seismic Analysis for the Fast Flux Test Facility.
A description is given of the analysis and results for the Fast Flux Test Facility (FFTF) reactor system which was analyzed for both scram times and seismic responses such as bending moments and impact forces. The reactor system was represented with a one...
A. Morrone
Assessment of Clinch River Breeder Reactor Plant Reliability Program and Safety Systems.
The design of the Clinch River Breeder Reactor (CRBR) reactor shutdown system (RSS) and the shutdown heat removal system (SHRS) has been reviewed by NUS Corporation in support of the NRC staff. The RSS and the SHRS were evaluated to assess the functional ...
B. D. Sullivan R. D. Keller W. E. Carson W. L. Partain
Performance characteristics of the annular core research reactor fuel motion detection system
Recent proof tests have shown that the annular core research reactor (ACRR) fuel motion detection system has reached its design goals of providing high temporal and spatial resolution pictures of fuel distributions in the ACRR. The coded aperture imaging system (CAIS) images the fuel by monitoring the fission gamma rays from the fuel that pass through collimators in the reactor
J. G. Kelly; K. T. Stalker
Numerical simulation of the power characteristics of twin-core pulse reactor-pumped laser system
Concept for high-power pulsed reactor-pumped laser system (RPLS) based on the new physical principles (direct nuclear-to-optical conversion) is discussed with reference to ICF feasibility problem. Theoretical problems for substantiation of the neutronic and physical characteristics of the RPLS power model are considered. Results of numerical studies of the expected power characteristics of reactor laser system are discussed.
Gulevich, A. V.; Barzilov, A. P.; Dyachenko, P. P.; Zrodnikov, A. V.; Kukharchuk, O. F.; Kachanov, B. V.; Kolyada, S. G.; Pashin, E. A.
System simulation of a multicell thermionic space power reactor
For many years, thermionic power has been considered for space application. The prominent feature of the power conversion system is that there are no moving parts. Although designs have been developed by various organizations, no comprehensive system models are known to exist which can simulate transient behavior of a multicell design nor is there a method to directly couple these models to other codes that can calculate variations in reactivity. Thus, a procedure has been developed to couple the performance calculations of a space nuclear reactor thermal/hydraulics code with a neutron diffusion code to analyze temperature feedback. Thermionic power is based on the thermionic emissions principle where free electrons in a conductor have sufficient energy to escape the surface. Kinetic energy is given to the electrons by heating the conductor. Specifically, a 48 kWe thermionic power converter system model has been developed and used to model startup and other transients. Less than 10% of the fuel heat is converted to electricity, and the rest is rejected to space via a heat pipe radiator. An electromagnetic pump circulates the liquid metal coolant. First, a startup transient model was developed which showed stable operation through ignition of the Thermionic Fuel Elements (TFEs) and thawing of the radiator heat pipes. Also, the model's capability was expanded to include two-phase heat transfer to model boiling using coupled mass and thermal energy conservation equations. The next step incorporated effects of reactivity feedback---showing that various mechanisms will prevent power and temperature run-up for a flow reduction scenario where the reactor control systems fail to respond. In particular, the Doppler effect was shown to counter a positive worth due to partial core voiding although steps must be taken to preclude film boiling in that high superheats will result in TFE failures. Finally, analysis of the core grid spacer location suggests it should be located at the core outlet only. Applicable operational data were also assessed for TOPAZ II tests. A steady-state analysis showed a good comparison with other modeling codes, and TFE performance agreed within 3% of the experimental data---thus, validating the performance calculations.
von Arx, Alan Vincent
Analysis data on samples from the TMI-2 reactor-coolant system and reactor-coolant bleed tank
Two liquid samples from the Three Mile Island Unit 2 (TMI-2) Reactor Coolant System (RCS) and three liquid samples from the three Reactor Coolant Bleed Tanks (RCBT) were taken during the time period March 29, 1979 to August 14, 1980. The samples were analyzed for radionuclide concentrations by two independent laboratories, Exxon Nuclear Idaho Co., Inc. (ENICO) and EG and G Idaho, Inc. at the Idaho National Engineering Laboratory (INEL). The RCS sample taken on March 29, 1979 was also analyzed by Science Applications, Inc. (SAI). This report presents the methods used and the results of these analyes. 14 tables.
Nitschke, R.L.
Lunar electric power systems utilizing the SP100 reactor coupled to dynamic conversion systems. Final report
An integration study was performed by Rocketdyne under contract to NASA-LeRC. The study was concerned with coupling an SP-0100 reactor to either a Brayton or Stirling power conversion system. The application was for a surface power system to supply power requirements to a lunar base. A power level of 550 kWe was selected based on the NASA Space Exploration Initiative
R. B. Harty; R. E. Durand
Richard B. Harty; Richard E. Durand
Incorporating ''fuzzy'' data and logical relations in the design of expert systems for nuclear reactors
This paper applies the method of assigning probability in Dempster-Shafer Theory (DST) to the components of rule-based expert systems used in the control of nuclear reactors. Probabilities are assigned to premises, consequences, and rules themselves. This paper considers how uncertainty can propagate through a system of Boolean equations, such as fault trees or expert systems. The probability masses assigned to primary initiating events in the expert system can be derived from observing a nuclear reactor in operation or based on engineering knowledge of the reactor parts. Use of DST mass assignments offers greater flexibility to the construction of expert systems.
Guth, M.A.S.
High upflow velocity and organic loading rate improve granulation in upflow anaerobic sludge blanket reactors
Five laboratory scale upflow anaerobic sludge blanket (UASB) reactors were seeded with nongranular sewage sludge. Granulation was obtained after 15¢35 days when between 0.5 and 2.0m\\/h upflow liquid velocity was applied, with an organic loading rate (OLR) of 8g COD\\/l.d (COD is the chemical oxygen demand). Granules had different physical characteristics and specific activity (g CODREMOVED\\/g volatile suspended solids) depending
A. Francese; P. C¾rdoba; J. Durßn; F. Si±eriz
Rapid granulation and sludge retention for tetrachloroethylene removal in an upflow anaerobic sludge blanket reactor
A laboratory scale upflow anaerobic sludge blanket (UASB) reactor was operated at 35 ░C for over 200 days to investigate the granulation mechanism during tetrachloroethylene (TCE) biodegradation. Anaerobic, unacclimated sludge and glucose were used as seed and primary substrate, respectively. TCE-degrading granules developed after 1.5 months of start-up. They grew at an accelerated pace for 7 months. The TCE-degrading granules
Benzaldehyde conversion by two anaerobic bacteria isolated from an upflow anaerobic sludge bed reactor
A benzaldehyde-degrading enrichment culture was obtained from mesophilic methanogenic granular sludge from a UASB (upflow anaerobic sludge bed) reactor treating potato starch wastewater. The enrichment culture degraded benzaldehyde rapidly to benzylalcohol and benzoate. Two benzaldehyde-degrading bacterial strains were isolated from the enrichment. Both strains could grow on yeast extract in the presence or absence of benzaldehyde. Strain BOR (DSM 12?858)
S. N. Parshina; R. Kleerebezem; E van Kempen; A. N. Nozhevnikova; G. Lettinga; A. J. M. Stams
This report describes the design and operation of the robotic equipment for remote withdrawal of fuel rods from the Light Water Breeder Reactor (LWBR) fuel modules for proof-of-breeding assay and physical examinations. The Rod Removal System (RRS) was automated to minimize operator errors in removing specified rods while maintaining maximum control over forces applied during removal to preclude damage. The system determined the exact orientation of the fuel module and the positions of fuel rods within the module. The module being derodded was oriented vertically in a support stand in a 35-foot water pit at the Expended Core Facility at the Idaho National Engineering Laboratory. The tops of preselected rods were engaged by a programmed mechanical grapple, which was capable of collecting rod pull force data while 10-foot long rods were withdrawn vertically from modules. Pulled rods were transferred to preselected ports in a multiport storage container or inserted into shrouds prepositioned in a rod transfer container. The RRS removed approximately 1100 fuel rods from 12 of the 39 LWBR fuel modules without a major equipment or operational problem. 3 refs., 19 figs.
Fodor, G.; Kikta, T.J.; Matchett, R.L.; Roof, D.R.; Wilczynski, R.
Towards Fusion Reactor Ignition the Adiabatic Toroidal Compression System
A major problem area in the study of the feasibility of fusion reactors is the attainment of hot dense plasma for experimental study and the determination of a heating scheme to reach ignition conditions in a reactor. Adiabatic compression in minor and major radius of Tokamak configuration plasmas was proposed as a means of reaching this end. The Adiabatic Toroidal
J. C. Citrolo
Remodeling of the Instrumentation and Control System of TRIGA MARK II Reactor.
It was required to remodel the instrumentation and control system of TRIGA MARK II reactor installed in 1962 due to the difficulty in acquiring spare parts, and aging of the equipments. The instrumentation and control system were designed and manufactured...
B. J. Koh B. S. Shim S. J. Han W. Y. Yun Y. J. Kwon
Trickle-bed reactor models for systems with a volatile liquid phase
A significant number of gas¢liquid¢solid catalyzed reactions in the petroleum processing and chemical industries are carried out in trickle-bed reactors under conditions where substantial volatilization of the liquid phase can occur. A review of the limited literature on experiments and models for trickle-bed reactor systems with volatile liquids is presented first. A rigorous model for the solution of the reactor
M. R. Khadilkar; P. L. Mills; M. P. Dudukovic
Direct-Drive Gas-Cooled Reactor Power System: Concept and Preliminary Testing
This paper describes the concept and preliminary component testing of a gas-cooled. UN-fueled, pin-type reactor which uses He\\/Xe gas that goes directly into a recuperated Brayton system to produce electricity for nuclear electric propulsion. This Direct-Drive Gas-Cooled Reactor (DDG) is designed to be subcritical under water or wet-sand immersion in case of a launch accident. Because the gas-cooled reactor can
S. A. Wright; R. J. Lipinski; T. J. Godfroy; S. M. Bragg-Sitton; M. K. Van Dyke
This report describes the optimization of the RISK III mathematical model, which provides risk assessment for the use of a plutonium-fueled, fission reactor in space systems. The report discusses possible scenarios leading to radiation releases on the ground; distinctions are made for an intact reactor and a dispersed reactor. Also included are projected dose equivalents for various accident situations. 54 refs., 31 figs., 11 tabs. (TEM)
Bartram, B.W.; Dougherty, D.K.
Electromagnetic Pumps for Main Cooling Systems of Commercialized Sodium-Cooled Fast Reactor
An electromagnetic pump (EMP) has superior potential to improve the economic performance and ease of maintenance of sodium-cooled fast reactors. This study investigates the adequateness of a modular-type EMP system for large-sized (1,500MWe class) sodium-cooled fast reactors. A flow rate of over 500 m\\/min is required for the main circulating pump of such reactors. There is concern that such a
Kosuke AIZAWA; Yoshitaka CHIKAZAWA; Shoji KOTAKE; Kuniaki ARA; Rie AIZAWA; Hiroyuki OTA
Hanging core support system for a nuclear reactor. [LMFBR
For holding the reactor core in the confining reactor vessel, a support is disclosed that is structurally independent of the vessel, that is dimensionally accurate and stable, and that comprises tandem tension linkages that act redundantly of one another to maintain stabilized core support even in the unlikely event of the complete failure of one of the linkages. The core support has a mounting platform for the reactor core, and unitary structure including a flange overlying the top edge of the reactor vessels, and a skirt and box beams between the flange and platform for establishing one of the linkages. A plurality of tension rods connect between the deck closing the reactor vessel and the platform for establishing the redundant linkage. Loaded Belleville springs flexibly hold the tension rods at the deck and separable bayonet-type connections hold the tension rods at the platform.
Burelbach, J.P.; Kann, W.J.; Pan, Y.C.; Saiveau, J.G.; Seidensticker, R.W.
Lunar electric power systems utilizing the SP-100 reactor coupled to dynamic conversion systems
An integration study was performed by Rocketdyne coupling an SP-100 reactor to either a Brayton, Stirling, or K-Rankine power conversion system. The application was for a surface power system to supply power requirements to a lunar base. A power level of 550 kWe was selected based on the National Aeronautics and Space Administration (NASA) Space Exploration Initiative 90-day study. Reliability studies were initially performed to determine optimum power conversion redundancy. This study resulted in selecting three operating engines and one standby unit. Integration design studies indicated that either of the three power conversion systems could be integrated with the SP-100 reactor. From a performance consideration, the Brayton and Stirling mass was approximately 45% higher than the K-Rankine. The K-Rankine radiator area was 45% of the Stirling, which in turn was about 40% of the Brayton.
Harty, Richard B.; Johnson, Gregory A.
Passive cooling system for top entry liquid metal cooled nuclear reactors
A liquid metal cooled nuclear fission reactor plant having a top entry loop joined satellite assembly with a passive auxiliary safety cooling system for removing residual heat resulting from fuel decay during shutdown, or heat produced during a mishap. This satellite type reactor plant is enhanced by a backup or secondary passive safety cooling system which augments the primary passive auxiliary cooling system when in operation, and replaces the primary cooling system when rendered inoperative.
Boardman, Charles E. (Saratoga, CA); Hunsbedt, Anstein (Los Gatos, CA); Hui, Marvin M. (Cupertino, CA)
Demountable low stress high field toroidal field magnet system for tokamak fusion reactors
A new type of superconducting magnet system for large fusion reactors is described in this report. Instead of winding large planar or multi-axis coils, as has been proposed in previous fusion reactor designs, the superconducting coils are made by joining together several prefabricated conductor sections. The joints can be unmade and sections removed if they fail. Conductor sections can be
J. Powell; D. Hsieh; J. Lehner; M. Suenaga
During the course of a hypothetical severe Pressurized Water Reactor accident, pressurization of the containment occurs and hydrogen can be produced by the reactor core oxidation. Inner spray systems are used in order to reduce the pressure, mix the gaseous mixture and collect the fission products on the droplets. Complex phenomena are involved during the spray injection, making difficult to
J. Malet; E. Porcheron; P. Cornet; J. Vendel
EPA Science Inventory
This report details the Superfund Innovative Technology Evaluation of Eco Logic International's gas-phase chemical reduction process, with an emphasis on their Reactor System. he Eco Logic process employees a high temperature reactor filled with hydrogen gas as the means to destr...
Integral nuclear power reactor with natural coolant circulation. Investigation of passive RHR system
The development of a small power (up to 240 MWe) integral PWR for nuclear co-generation power plants has been carried out. The distinctive features of this advanced reactor are: primary circuit arrangement in a single pressure vessel; natural coolant circulation; passive safety systems with self-activated control devices; use of a second (guard) vessel housing the reactor; favourable conditions for the
O. B. Samoilov; V. S. Kuul; V. A. Malamud; G. I. Tarasov
Membrane sequencing batch reactor system for the treatment of dairy industry wastewater
A membrane separation process was coupled to a sequencing batch reactor (SBR) for biological nutrient removal (BNR) processes and a combined system was named a membrane sequencing batch reactor (MSBR). MSBR was used for the treatment of dairy industry wastewater and optimized to increase the treatment efficiency. Since a diffuser-attached module design, subcritical flux operation, and intermittent suction method were
Tae-Hyun Bae; Sung-Soo Han; Tae-Moon Tak
Acoustic emission system calibration at Watts Bar Unit 1 nuclear reactor
An acoustic emission system has been installed on TVA's Watts Bar Unit 1 reactor to monitor selected areas of the pressure boundary during hydrostatic testing, hot functional testing, and ultimately, during reactor startup and operation. This is a part of a cooperative effort between TVA and NRC Research to test and demonstrate AE technology. This technology has been developed under
P. H. Hutton; M. A. Friesel; J. F. Dawson; J. C. Harris
The Gas-Cooled Fast Reactor: Report on Safety System Design for Decay Heat Removal
The gas-cooled fast reactor (GFR) was chosen as one of the Generation IV nuclear reactor systems to be developed based on its excellent potential for sustainability through reduction of the volume and radiotoxicity of both its own fuel and other spent nuclear fuel, and for extending\\/utilizing uranium resources orders of magnitude beyond what the current open fuel cycle can realize.
K. D. Weaver; T. Marshall; T. Y. C. Wei; E. E. Feldman; M. J. Driscoll; H. Ludewig
Advanced control system for the Integral Fast Reactor fuel pin processor.
A computerized control system has been developed for the remotely-operated fuel pin processor used in the Integral Fast Reactor Program, Fuel Cycle Facility (FCF). The pin processor remotely shears cast EBR- reactor fuel pins to length, inspects them for ...
L. D. Lau P. F. Randall R. W. Benedict D. Levinskas
Study on the microaerobic EGSB reactor+chemical coagulation system treating domestic wastewater
A novel domestic wastewater treatment system for reuse was proposed, which consisted of a microaerobic EGSB reactor unit and the following chemical phosphorus removal unit, as a low-cost and highly efficient process. In order to confirm the feasibility of the domestic wastewater treating technique at ambient temperature for reuse through the combination of the micro-aerobic EGSB reactor and the chemical
Chunjuan Dong; Qingye Pan
Reference Zrh Reactor Power System for NASA Space Station Post-Operational Reentry Analysis.
The flight dynamic and heating of a spent ZrH reactor power system returning from orbit at the end of its useful life are analyzed. The results of this analysis indicate that the reactor with a large portion of the lithium shield still surrounding it will...
R. D. Elliott
Calculations of reactivity-initiated transients in gas-cooled fast reactors using the code system fast
The FAST code system is a general tool for analyzing advanced reactors from the viewpoint of the static and dynamic behavior of the whole reactor system. It includes an integrated three-dimensional representation of the core neutronics, appropriate modeling of the core thermal-hydraulics and fuel pin behavior, coupled to models of the reactor primary and secondary systems. Use is made largely
S. Pelloni; E. Bubelis; K. Mikityuk; P. Coddington
An integration study was performed by coupling an SP-100 reactor to either a Brayton or Stirling power conversion subsystem. The application was for a surface power system to supply power requirements to a lunar base. A power level of 550 kWe was selected based on the NASA Space Exploration Initiative 90-day study. Reliability studies were initially performed to determine optimum power-conversion redundancy. This study resulted in selecting three operating engines and one standby unit. Integratiaon-design studies indicated that either the Brayton or Stirling power conversion subsystem could be integrated with the SP-100 reactor. The Stirling system had an integration advantage because of smaller piping size and fewer components. The Stirling engine, however, is more complex and heavier than the Brayton rotating unit, which tends to offset the Stirling integration advantage. From a performance consideration, the Brayton had a 9-percent mass advantage and the Stirling a 50-percent radiator-area advantage.
Harty, Richard B.; Durand, Richard E.; Mason, Lee S.
Neutron Density Fluctuations in Point Reactor Systems with Dichotomic Reactivity Noise
The exactly solvable stochastic point reactor model systems are analyzed through the stochastic Liouville equation. Three kinds of model systems are treated: (1) linear system without delayed neutrons, (2) linear system with one-group of delayed neutrons, and (3) nonlinear system with direct power feedback. The exact expressions for the fluctuations of neutron density, such as the moments, autocorrelation function and
Okitsugu SAKO
Air cylinders moving heavy components (100 to 300 lbs) at high speeds (above 300 in\\/sec) present a formidable end-cushion-shock problem. With no speed control, the moving components can reach over 600 in\\/sec if the air cylinder has a 5 ft stroke. This paper presents an overview of a successful upgrade modification to an existing reactor control rod drive design using
C. W. Solbrig; W. W. Stevens
Effect of upflow velocity on the effluent membrane fouling potential in membrane coupled upflow anaerobic sludge blanket reactors.
This study investigated the effect of upflow velocity (Vup) on biological removal efficiency and effluent filterability in a laboratory scale upflow anaerobic sludge blanket (UASB) reactor. Upflow velocities of 1.2, 0.6 and 1.2m/h were applied in three successive stages over a total operation period of 116 days. Filterability tests were carried out during each stage in order to assess the effect of Vup on subsequent membrane performance. Results indicated a significant impact of Vup on both biological performance and physicochemical effluent characteristics. The observed differences in protein/carbohydrate ratio and particle size distribution (PSD), which play important roles in membrane fouling, lead to the hypothesis that Vup is a critical parameter for effluent filterability in membrane coupled UASB reactors. Results showed that filterability of the effluent during the operation at 0.6m/h was better than that during the operation at 1.2m/h. PMID:23999261
Ozgun, Hale; Ersahin, Mustafa Evren; Tao, Yu; Spanjers, Henri; van Lier, Jules B
Seismic evaluation of safety systems at the Savannah River reactors
A thorough review of all safety related systems in commercial nuclear power plants was prompted by the accident at the Three Mile Island Nuclear Power Plant. As a consequence of this review, the Nuclear Regulatory Commission (NRC) focused its attention on the environmental and seismic qualification of the industry`s electrical and mechanical equipment. In 1980, the NRC issued Unresolved Safety Issue (USI) A-46 to verify the seismic adequacy of the equipment required to safely shut down a plant and maintain a stable condition for 72 hours. After extensive research by the NRC, it became apparent that traditional analysis and testing methods would not be a feasible mechanism to address this USI A-46 issue. The costs associated with utilizing the standard analytical and testing qualification approaches were exorbitant and could not be justified. In addition, the only equipment available to be shake table testing which is similar to the item being qualified is typically the nuclear plant component itself. After 8 years of studies and data collection, the NRC issued its ``Generic Safety Evaluation Report`` approving an alternate seismic qualification approach based on the use of seismic experience data. This experience-based seismic assessment approach will be the basis for evaluating each of the 70 pre-1972 commercial nuclear power units in the United States and for an undetermined number of nuclear plants located in foreign countries. This same cost-effective developed for the commercial nuclear power industry is currently being applied to the Savannah River Production Reactors to address similar seismic adequacy issues. This paper documents the results of the Savannah River Plant seismic evaluating program. This effort marks the first complete (non-trial) application of this state-of-the-art USI A-46 resolution methodology.
Hardy, G.S.; Johnson, J.J.; Eder, S.J. [EQE Engineering, Inc., San Francisco, CA (United States); Monahon, T.M.; Ketcham, D.R. [Westinghouse Savannah River Co., Aiken, SC (United States)
A thorough review of all safety related systems in commercial nuclear power plants was prompted by the accident at the Three Mile Island Nuclear Power Plant. As a consequence of this review, the Nuclear Regulatory Commission (NRC) focused its attention on the environmental and seismic qualification of the industry's electrical and mechanical equipment. In 1980, the NRC issued Unresolved Safety Issue (USI) A-46 to verify the seismic adequacy of the equipment required to safely shut down a plant and maintain a stable condition for 72 hours. After extensive research by the NRC, it became apparent that traditional analysis and testing methods would not be a feasible mechanism to address this USI A-46 issue. The costs associated with utilizing the standard analytical and testing qualification approaches were exorbitant and could not be justified. In addition, the only equipment available to be shake table testing which is similar to the item being qualified is typically the nuclear plant component itself. After 8 years of studies and data collection, the NRC issued its Generic Safety Evaluation Report'' approving an alternate seismic qualification approach based on the use of seismic experience data. This experience-based seismic assessment approach will be the basis for evaluating each of the 70 pre-1972 commercial nuclear power units in the United States and for an undetermined number of nuclear plants located in foreign countries. This same cost-effective developed for the commercial nuclear power industry is currently being applied to the Savannah River Production Reactors to address similar seismic adequacy issues. This paper documents the results of the Savannah River Plant seismic evaluating program. This effort marks the first complete (non-trial) application of this state-of-the-art USI A-46 resolution methodology.
Hardy, G.S.; Johnson, J.J.; Eder, S.J. (EQE Engineering, Inc., San Francisco, CA (United States)); Monahon, T.M.; Ketcham, D.R. (Westinghouse Savannah River Co., Aiken, SC (United States))
Boiling water reactor plant with hybrid pressure containment cooling system
This patent describes a reactor plant. It comprises a containment structure defining a wet well, dry well, an isolation chamber means, a transducer chamber means; a two-phase reactor; a transducer for converting energy stored in heat-transfer vapor into another form of energy; transducer conduit means for conveying heat-transfer vapor to the transducer from the reactor; pressure relief means for relieving excessive pressure within the reactor vessel by conveying heat-transfer fluid, primarily heat-transfer vapor, from the vessel to the isolation chamber means in the event of the excessive pressure; a condenser having a distributor, a manifold, and a receiver; separator means for separating liquid from gas so that heat-transfer liquid exiting the condensor can be separated from heat-transfer vapor and noncondensable gas exiting the condenser, condensate return means for conveying heat-transfer liquid from the separator means to the reactor vessel; and emergency conduit means for conveying noncondensable gas from the separator means to the well during a loss-of-coolant accident.
Van Kuijk, R.M.
Hanging core support system for a nuclear reactor
For holding the reactor core in the confining reactor vessel, a support is disclosed that is structurally independent of the vessel, that is dimensionally accurate and stable, and that comprises tandem tension linkages that act redundantly of one another to maintain stabilized core support even in the unlikely event of the complete failure of one of the linkages. The core support has a mounting platform for the reactor core, and unitary structure including a flange overlying the top edge of the reactor vessels, and a skirt and box beams between the flange and platform for establishing one of the linkages. A plurality of tension rods connect between the deck closing the reactor vessel and the platform for establishing the redundant linkage. Loaded Belleville springs flexibly hold the tension rods at the deck and separable bayonet-type connections hold the tension rods at the platform. Motion or radiation sensing detectors can be provide at the lower ends of the tension rods for obtaining pertinent readings proximate the core.
Burelbach, James P. (Glen Ellyn, IL); Kann, William J. (Park Ridge, IL); Pan, Yen-Cheng (Naperville, IL); Saiveau, James G. (Hickory Hills, IL); Seidensticker, Ralph W. (Wheaton, IL)
Decomissioning of nuclear reactors - methods for calculation of radionuclide inventories in contaminated BWR systems.
The purpose of the study has been to develop and demonstrate calculation models for the prediction of radionuclide inventories in contaminated systems in the Nordic BWRs at the time of decommissioning. Oskarshamn 2 was selected as reference reactor for th...
K. Lundgren
Relationships and Influences of Fuel and Coolant System Processes during LWR (Light Water Reactor) Severe Accidents.
The report places the processes of fuel and core damage, reactor coolant system (RCS) flow and heat transfer, and pressure vessel breach -- and their respective fission product considerations -- in the context of typical risk-dominant accident sequences. ...
J. B. Rivard
Thermal hydraulic tests for reactor safety system -Research on the improvement of nuclear safety-.
The present research aims at the development of the thermal hydraulic verification test technology for the reactor safety system of the conventional and advanced nuclear power plant and the development of the advanced thermal hydraulic measuring technique...
M. K. Chung C. K. Park S. K. Yang C. H. Chung S. Y. Chun
Mitigation of steam generator tube rupture in a pressurized water reactor with passive safety systems
The effects of steam generator tube ruptures in a pressurized water reactor are mitigated by reducing the pressure in the primary loop by diverting reactor coolant through the heat exchanger of a passive heat removal system immersed in the in containment refueling water storage tank in response to a high feed water level in the steam generator. Reactor coolant inventory is maintained by also in response to high steam generator level introducing coolant into the primary loop from core make-up tanks at the pressure in the reactor coolant system pressurizer. The high steam generator level is also used to isolate the start-up feed water system and the chemical and volume control system to prevent flooding into the steam header. 2 figures.
McDermott, Daniel J. (Export, PA); Schrader, Kenneth J. (Penn Hills, PA); Schulz, Terry L. (Murrysville Boro, PA)
Evaluation and optimization of General AtomicsÆ GT-MHR reactor cavity cooling system using an axiomatic design approach
The development of the Generation IV (Gen-IV) nuclear reactors has presented social, technical, and economical challenges to nuclear engineering design and research. To develop a robust, reliable nuclear reactor system with minimal environmental impact and cost, modularity has been gradually accepted as a key concept in designing high-quality nuclear reactor systems. While the establishment and reliability of a nuclear power
Jeff Thielman; Ping Ge; Qiao Wu; Laurence Parme
Common-Cause Failure Analysis for Reactor Protection System Reliability Studies
Analyses were performed of the safety-related performance of the reactor protection system (RPS) at U.S. Westinghouse and General Electric commercial reactors during the period 1984 through 1995. RPS operational data from these reactors were collected from the Nuclear Plant Reliability Data System (NPRDS) and Licensee Event Reports (LER). The common-cause failure (CCF) modeling in the fault trees developed for these studies and the analysis and use of common-cause failure data were sophisticated, state-of-the-art efforts. The overall CCF effort helped to test and expand the limits of the U.S. Nuclear Regulatory Commission's CCF methodology.
Gentillon, C.; Rasmuson, D.; Eide, S.; Wierman, T.
Digital computer study of nuclear reactor thermal transients during startup of 60-kWe Brayton power conversion system
A digital computer study was made of reactor thermal transients during startup of the Brayton power conversion loop of a 60-kWe reactor Brayton power system. A startup procedure requiring the least Brayton system complication was tried first; this procedure caused violations of design limits on key reactor variables. Several modifications of this procedure were then found which caused no design limit violations. These modifications involved: (1) using a slower rate of increase in gas flow; (2) increasing the initial reactor power level to make the reactor respond faster; and (3) appropriate reactor control drum manipulation during the startup transient.
Jefferies, K. S.; Tew, R. C.
Radionuclide inventories for short run-time space nuclear reactor systems
Space Nuclear Reactor Systems, especially those used for propulsion, often have expected operation run times much shorter than those for land-based nuclear power plants. This produces substantially different radionuclide inventories to be considered in the safety analyses of space nuclear systems. This presentation describes an analysis utilizing ORIGEN2 and DKPOWER to provide comparisons among representative land-based and space systems. These comparisons enable early, conceptual considerations of safety issues and features in the preliminary design phases of operational systems, test facilities, and operations by identifying differences between the requirements for space systems and the established practice for land-based power systems. Early indications are that separation distance is much more effective as a safety measure for space nuclear systems than for power reactors because greater decay of the radionuclide activity occurs during the time to transport the inventory a given distance. In addition, the inventories of long-lived actinides are very low for space reactor systems.
Coats, R.L.
Gas Core Reactor with Magnetohydrodynamic Power System and Cascading Power Cycle
The U.S. Department of Energy initiative Generation IV aim is to produce an entire nuclear energy production system with next-generation features for certification before 2030. A Generation IV-capable system must have superior sustainability, safety and reliability, and economic cost advantages in comparison with third generation light water reactors (LWRs). A gas core reactor (GCR) with magnetohydrodynamic (MHD) power converter and
Blair M. Smith; Samim Anghaie
Sodium leak detection system for liquid metal cooled nuclear reactors
A light source is projected across the gap between the containment vessel and the reactor vessel. The reflected light is then analyzed with an absorption spectrometer. The presence of any sodium vapor along the optical path results in a change of the optical transmissivity of the media. Since the absorption spectrum of sodium is well known, the light source is chosen such that the sensor is responsive only to the presence of sodium molecules. The optical sensor is designed to be small and require a minimum of amount of change to the reactor containment vessel.
Modarres, Dariush (12 La Vista Verde, Rancho Palos Verdes, CA 90