What Was the Pu-240 Content of the Plutonium Used in the U.S. 1962 Nuclear Test of Reactor-Grade Plutonium?
By Gregory S. Jones
May 6, 2013
In 1977, the U.S. declassified the fact that in 1962 it had successfully tested a nuclear weapon using reactor-grade plutonium. In 1994 additional information about this test was released. Though on the face of it this test would seem to definitively settle the issue about whether reactor-grade plutonium can be used in nuclear weapons, ironically the specifics related to this nuclear test have generated some of the most controversy.
Only a few facts about this successful nuclear test were released. Its yield was less than 20 kilotons, it was detonated underground at the Nevada Test Site and the plutonium used in the test was provided to the U.S. by the United Kingdom under the 1958 United States/United Kingdom Mutual Defense Agreement.
The test was specifically conducted to “obtain nuclear design information concerning the feasibility of using reactor-grade plutonium as the nuclear explosive material.” The Department of Energy (DOE) statement goes on to say, “The United States maintains an extensive nuclear test data base and predictive capabilities. This information, combined with the results of this low yield test, reveals that weapons can be constructed with reactor-grade plutonium.” This last statement is very important and is almost always ignored in discussions about this test. It says that U.S. statements about the utility of reactor-grade plutonium for the production of nuclear weapons is not based only on this test but rather its entire nuclear test database and the predictive capabilities that have resulted. Therefore the U.S. need not have conducted nuclear tests with plutonium of all possible concentrations of Pu-240 to know that nuclear weapons can be manufactured from such material.
The U.S. has not revealed which test in 1962 was the test that used reactor-grade plutonium. The U.S. conducted the most nuclear tests in 1962 of any year—96. Even if one selects only those tests where the yield is described as being less than 20 kilotons, was conducted underground in Nevada, and was weapons related, one finds that there are 36 such tests, the earliest was January 30 and the latest was December 14.
The U.S. has not revealed the exact Pu-240 content of the reactor-grade plutonium used in this test. Further the DOE statement about this test points out that in 1962 any plutonium with Pu-240 content higher than 7% would have been considered reactor-grade and that the current definitions of plutonium grades used by the DOE and in particular that of fuel-grade plutonium (Pu-240 between 7% and 19%) did not come into use until the 1970s. Having pointed this fact out, the DOE statement then fails to say which of these two definitions of reactor-grade plutonium it is using when describing this test. This fact has allowed many to claim that the plutonium used in this test was fuel-grade rather than reactor-grade.
In 1996, Alexander DeVolpi, writing in the Physics and Society Newsletter, suggested that there is “government deception” regarding the withheld data on the 1962 test. Based on a personal communication from “R.V. Hesketh”, he asserts that British sources claim that the plutonium used in the test could not have been what is now defined as reactor-grade but rather was fuel-grade. Puzzlingly he then says that the plutonium might have been reactor-grade (less than 81% fissile) but near the boundary with fuel-grade plutonium. He also suggests that the plutonium might not have been produced in the UK but rather might have been produced in Canada or even in the U.S. and then transferred to the UK and then back to the U.S. to hide the material’s origins.
At about the same time, John Carlson et al. from the Australian Safeguards and Non-Proliferation Office (ASNO) suggested that the plutonium used in this test was “what would now be termed ‘fuel-grade,’ probably closer to the weapons-grade end of the fuel-grade range.” Similar such statements have been made in other ASNO documents. In 2006 ASNO published a diagram which showed that it had revised its views somewhat as it now shows the plutonium having a likely Pu-240 content of between 14% and 18% i.e. near the reactor-grade end of the fuel-grade range.
In 2002 Bruno Pellaud, the former Deputy Director General of the International Atomic Energy Agency, stated that the DOE announcement was misleading and that the plutonium used in this test was fuel-grade with a Pu-240 content of only 12%. Pellaud’s reference for this important assertion is a private communication from an unnamed source. He also cites Albright et al. as saying that the plutonium could not have been produced at the UK’s Calder Hall and Chapelcross military plutonium production reactors since the burnup was too low.
Looking at Albright et al.’s statements in more detail, they claim that the U.S. announcement had caused a “lively private debate” between the British and U.S. governments since as was stated in the last paragraph, it is claimed that Calder Hall and Chapelcross reactors were not producing reactor-grade plutonium. They then go on to contradict this statement by saying that in fact the British Defense Minister had confirmed the U.S. statement to the House of Commons. Despite having official statements from both the British and U.S. governments that the plutonium had originated in the UK, Albright et al. say that the source of the plutonium used in the 1962 test has not been identified and that it is unclear whether the material was produced in the U.S. or the UK. Though they claim that the source of the plutonium is highly uncertain they say “it [the plutonium] was definitely fuel- rather than reactor-grade.”
Also though Albright et al. focus on British plutonium production “before 1962,” as was noted above, the test might well have occurred in late 1962 (5 of the 36 possible tests referred to above, occurred in December). Therefore the fuel could have still been in British reactors as late as mid-1962 and there would have still been time for the plutonium to be provided to the U.S.
Statements that the plutonium in the 1962 test was fuel-grade are becoming quite common. For a number of years the World Nuclear Association has stated that the plutonium used in this test contained about 85% Pu-239. This would imply a Pu-240 content of about 13% to 14%. Such statements are now finding their way to sources such as Wikipedia.
Now why is it so important what the exact Pu-240 content of the plutonium was? Would it make that much difference if the Pu-240 content was 15% as opposed to 20% or 25%? As was discussed above, the purpose of this test was to validate U.S. calculations on the utility of plutonium with a relatively high Pu-240 content. There is no reason why this objective could not be achieved using plutonium with a Pu-240 content of just 15%.
Many of those who assert that the plutonium in the 1962 test was fuel-grade rather than reactor-grade plutonium also then make the statement that in all of the years of nuclear testing no country has ever used reactor-grade plutonium in a nuclear explosive. Such a statement sounds impressive but really is just empty rhetoric. After all, as far as is known, no country has ever used either neptunium or U-235 produced by laser enrichment for a nuclear weapon. Yet the weapons usability of these materials is determine solely by their nuclear and physical properties, not by whether anyone has used them before now. No one doubts that such materials could be used to manufacture nuclear weapons.
At any rate as we will see, it is very likely that the Pu-240 content of the 1962 nuclear test was in the range of 20% to 23% i.e. truly reactor-grade. It is quite implausible that it was as low as 12% to 14%.
At first glance it does seem odd that the U.S. would use plutonium obtained from the UK. After all, in the second half of the 1950s, the U.S. had eight plutonium production reactors in operation at Hanford in Washington State. If the U.S. wanted plutonium with a high Pu-240 content why would not the U.S. just make it itself? The answer is that the U.S. tried but failed.
In October 1957 Hanford received a request from the U.S. Atomic Energy Commission to produce 11 kilograms of plutonium with a Pu-240 content of 20%. This was the first time that Hanford had been asked to produce plutonium with a high Pu-240 content and fulfilling this request was not a straightforward matter. If Hanford were to irradiate natural uranium to meet this request, it would require Hanford to subject the natural uranium fuel to a burn-up of around 3,800 MWD/Te. As Hanford had not ever irradiated natural uranium to burn-ups of higher than about 1,200 to 1,400 MWD/Te (Pu-240 content of 9% to 10%), this would require burn-ups of roughly triple what had ever been done before.
A constant concern for the reactor operators at Hanford was the rupture of the metallic uranium fuel elements. A rupture would expose the hot metallic uranium to the water coolant, leading it to oxidize and swell which would block the fuel channel. This could cut off the flow of coolant to the fuel elements in the same fuel channel which in the worst case would lead those elements to overheat, catch fire, and set the entire reactor ablaze. Therefore there were systems that detected the release of radioactivity when a rupture occurred. The reactor would then have to be shutdown immediately and the ruptured fuel element removed. In some cases the fuel element would already be sufficiently swollen so that great force would be needed to remove it from the reactor. Sometimes this effort would damage the aluminum tube in which the fuel and water coolant were contained so badly that the tube would have to be replaced. Fuel ruptures were a major cause of lost reactor operating time and thereby lost plutonium production. The chance that a fuel element would rupture increased the higher the fuel burn-up.
In order to try to avoid these problems, Hanford decided to use depleted uranium with a U-235 content of only 0.15% instead of the natural concentration of 0.71%. The use of this depleted uranium would lessen the number of fissions that occurred in the fuel and it was hoped, decrease the chance that the fuel would rupture. Hanford estimated that it would require the irradiation of about 65 to 70 “tubes” (reactor fuel channels) worth of depleted uranium fuel elements to produce the required amount of 20% Pu 240 plutonium. As a safety margin Hanford used 84 tubes of depleted uranium which if totally successful would have produced about 14 kilograms of plutonium with a Pu-240 content of 20%.
On seven different dates during March, April and May of 1958 these depleted uranium fuel elements were loaded into the C reactor. It was anticipated that it would take irradiations of about 12 to 14 months to produce the required plutonium. However, in September 1958 there was the first fuel rupture in this batch of fuel. This rupture was fuel that had been loaded only six months earlier. In October there were four more ruptures and five more in November. In addition there was evidence that swelling in other fuel elements was making it difficult to move them in the fuel channel. All elements in channels containing either ruptured or swollen fuel elements were removed.
By this time nearly half of the initial fuel elements had been discharged. Hanford manufactured eight additional tubes of depleted uranium fuel elements using what was hoped would be an improved method. These new fuel elements were charged into the C reactor in November 1958. There was an additional rupture in the original depleted fuel in December and two more in January which were only two days apart. As a result all of the rest of the original depleted uranium fuel was discharged.
Irradiation of the new depleted fuel elements continued but in September 1959 one of these elements ruptured and all of this fuel was discharged as well. It was determined that the improvement in these newer fuel elements was marginal at best. Nearly two years after the initial request, Hanford had to admit defeat and there would be no further efforts to produce high Pu-240 plutonium until 1964. However, this effort did result in the production of about 10 kilograms of plutonium with a Pu-240 content of 15%.
The effect of this failure was almost immediate. Hanford had been expecting to receive from Oak Ridge a shipment of 1.2 kilograms of plutonium with a Pu-240 content of 20%. This plutonium was to be used in the Physics Constants Test Reactor. However, Hanford was informed that it would not be receiving this material because “The Division of Military Applications” had exercised “a prior claim” on this material. Work at Hanford had to be suspended illustrating just how rare plutonium with a high Pu-240 content was in 1959.
Now it is clear why the U.S. had to approach the British for help. But how did the British come to possess plutonium with a high Pu-240 content? The UK had eight virtually identical plutonium production reactors, four at Calder Hall and four at Chapelcross which were being operated by the United Kingdom Atomic Energy Authority (U.K.A.E.A.). Like the U.S. reactors at Hanford, these eight reactors used graphite as a moderator but unlike the U.S. reactors the British ones were designed to produce electricity as well. There is no British source that states what the burn-up of the fuel from these reactors was during the 1950s and early 1960s but apparently the fuel was only irradiated for about one year.It is easy to calculate that this irradiation period would produce burnups of no more than 1,000 MWD/Te which would result in plutonium being produced with a Pu-240 content of 8% or less, i.e. British weapons grade plutonium. Since it is known that the primary mission of these reactors during this time was the production of weapons grade plutonium, this is hardly surprising.
The British were also building a series of reactors to be operated by the civilian Central Electricity Generating Board (CEGB). These reactors were scaled up versions of Calder Hall and Chapelcross reactors but their mission was to produce electricity which for economic reasons meant that they would try to achieve the highest fuel burn-up possible. When these reactors started operation it was thought that the fuel could reach an average burn-up of 3,000 MWD/Te (Pu-240 content of about 17%) and hoped that it might be able to reach 5,000 MWD/Te (Pu-240 content of about 25%--this hope would be fulfilled). However, the first two of these reactors (Berkeley 1 and Bradwell 1) only started operation in the summer of 1962. Since it would take about one year for these reactors to produce plutonium with a Pu-240 content of more than 8%, these reactors were obviously not the source of the plutonium for the 1962 test. At first glance then, neither the plutonium production reactors nor the civil power reactors could have been the source of the plutonium for the 1962 test.
The solution to this seeming puzzle is that though the Calder Hall and Chapelcross reactors’ primary mission was to produce weapons grade plutonium, it was not their only mission. In particular, with the advent of the CEGB power reactors there was a need to test the fuel that would be used in these reactors to see if they could attain the relatively high burn-up needed to make these reactors economic. What better place to test such fuel than in the Calder Hall and Chapelcross reactors which were essentially identical in design in the new CEGB reactors. This was especially so since the U.K.A.E.A. which operated these reactors would be providing the fuel for the CEGB reactors.
Hardy et al., writing in the latter part of 1962, indicated that as part of the high burnup testing program at the Calder Hall and Chapelcross reactors, average channel burnups of over 3,000 MWD/Te had been achieved. This burnup level would mean that the central fuel elements would have obtained a burnup of about 4,500 MWD/Te and it was reported that the highest burnup obtained by any fuel element was 4,650 MWD/Te. The Calder Hall and Chapelcross reactors used six fuel elements per fuel channel. By segregating the central two fuel elements from the fuel channels, one could obtain plutonium with a Pu-240 content of 23%. One could double the amount of plutonium obtained if the four central fuel elements were processed together. The resultant plutonium would blend to a Pu-240 content of about 20%. Stewart has published mean and peak fuel burnups obtained in various of the high burnup fuel channels in the Calder Hall and Chapelcross reactors as of August 1963. Interpolating the data back to mid-1962 confirms Hardy’s paper’s burnup levels and also shows that there were a sufficient number of high burnup fuel channels so that kilogram quantities of plutonium with a Pu-240 content of 20% to 23% would have been available in mid-1962. Now it is clear why the U.S. approached the UK for help.
None of this directly indicates the Pu-240 content of the plutonium in the U.S. 1962 test. However in 1993, J. Carson Mark who was head of the Los Alamos Theoretical Division from 1947 to 1972 said that the 1962 test used plutonium with the highest Pu-240 content available. Since the U.S. had already produced plutonium with a Pu-240 content of 15%, claims by Pellaud, Carlson et al. and the World Nuclear Association that the plutonium had only a Pu-240 content of 12% or 14% are obviously not true.
Further the Pu-240 content must have been significantly higher than 15%, otherwise there would have been no reason to have approached the British. As we have seen the highest available Pu-240 content from the British was in the range of 20% to 23%. Given what Mark has said about using the highest Pu-240 content available, it is very likely that the 20% to 23% range represents what was used in the 1962 test. This conclusion is supported by the observation that the original requirement for Hanford had been a Pu-240 content of 20%. Also recall that in November 1959 Hanford did not receive 1.2 kilograms of plutonium with a Pu-240 content of 20% because The Division of Military Applications had exercised a prior claim on the plutonium. So despite numerous statements to the contrary, it appears that the plutonium in the 1962 test was reactor-grade after all even by the current definition requiring such material to have a Pu-240 content of at least 19% and was very likely in the range of 20% to 23% Pu-240.
No doubt there will be some who will argue that even if the 1962 test did use plutonium with a Pu-240 content of 20% or 23% that plutonium discharges from current reactors have a significantly higher Pu-240 content (the equivalent of over 30%) and that such material has never be tested in a nuclear weapon. While such a statement would be true, it ignores the point discussed above that is worth repeating: “The United States maintains an extensive nuclear test data base and predictive capabilities. This information combined with the results of this low yield test, reveals that weapons can be constructed with reactor-grade plutonium.” U.S. statements about the utility of reactor-grade plutonium for the production of nuclear weapons are not based only on the 1962 nuclear test but rather its entire nuclear test database and the predictive capabilities that have resulted. Therefore the U.S. need not have conducted nuclear tests with plutonium of all possible concentrations of Pu-240 to know that nuclear weapons can be manufactured from such material.
In 1976, U.S. nuclear weapon designer Robert W. Selden stated: “The concept of ‘denatured’ plutonium (Pu which is not suitable for nuclear explosives) is fallacious.” Yet despite repeated authoritative statements from both the U.S. and British governments there are still those who try to argue that plutonium can be isotopically altered so that it is denatured and cannot be used to manufacture nuclear weapons. The claim that the 1962 nuclear test was of fuel-grade rather than reactor-grade plutonium is only one example of the fallacious arguments being used. Others have used calculations of weapon predetonation probabilities or thermal analysis of weapons to try to argue this same point. However, these analyses are flawed as well and the U.S. has made clear that despite the higher neutron background or thermal output of reactor-grade plutonium, this material can be used to manufacture devastating nuclear weapons. It is time for this harsh fact to be generally acknowledged.
 The author has multiple affiliations. This paper was produced for the Nonproliferation Policy Education Center. Though the author is also a part-time adjunct staff member at the RAND Corporation, this paper is not related to any RAND project and RAND bears no responsibility for any of the analysis and views expressed in it.
 All quotations in this paragraph are from Ibid.
 The U.S. currently defines weapon-grade plutonium as having a Pu-240 content of less than 7%. It defines fuel-grade plutonium as having a Pu-240 content of between 7% and less than 19% and defines reactor-grade plutonium as having a Pu-240 content of 19% or more. See: Plutonium: The First 50 Years, DOE/DP-0137, U.S. Department of Energy, February 1996, p.17.
 A. Devolpi, “A Coverup of Nuclear Test Information?” Physics and Society newsletter, Vol. 25, No.4, October 1996.
 John Carlson, John Bardsley, Victor Bragin, John Hill, “Plutonium Isotopics—Nonproliferation and Safeguards Issues,” Australian Safeguards Office, IAEA-SM-351/64.
 “Reactor-Grade Plutonium: Use in Weapon Tests,” ASNO Information Sheet, December 2006 (revised August 2008).
 Bruno Pellaud, “Proliferation aspects of plutonium recycling,” Journal of the Institute of Nuclear Material Management, Fall, 2002, p.3.
 David Albright, Frans Berkhout, and William Walker, Plutonium and Highly Enriched Uranium 1996: World Inventories, Capabilities and Policies, SIPRI, Oxford University Press, 1997, pp. 61-62.
 Forrest notes that the Tendrac nuclear test on December 7, 1962 is listed as being a joint US-UK test and suggested that this may be the date of the test. See: Eric Forrest, “Assessing the Proliferation Risk of Reactor Grade Plutonium, Massachusetts Institute of Technology, Fall 2010 p. 7 and United States Nuclear Tests, July 1945 through September 1992, DOE/NV—209-REV 15, U.S. Department of Energy, Nevada Operations Office, December 2000, p.27
 At this time the British cooled their spent fuel for 100 days before reprocessing. See: J.M. Kay, C.G. James, K. Saddington, and C.J. Turner, “Chemical processes,” The Journal of British Nuclear Energy Conference, Vol. 4, No. 2, April 1959, p.136. If, for example, fuel was discharged on June 30, 1962, then there would be more than enough time (60 days) for the separated plutonium to be transported to the U.S. and fabricated for a test on December 7.
 “Feature Report: Depleted Uranium Irradiations in the Single-Pass Reactors to Produce High Pu-240 Plutonium,” Monthly Report, September 1968, DUN-4452, Douglas United Nuclear, Inc., Richland Washington, October 16, 1968. Note that U.S.AEC operations were compartmented so that for most of its history Hanford was never told why it was requested to produce any particular reactor product including this batch of plutonium.
 There were 36 fuel elements in each tube. Only the central 26 were depleted uranium, the other 10 were natural uranium. This arrangement “centered” the depleted elements in the region with higher neutron flux.
 W.A. Blanton, “I & E Depleted Uranium Fuel Element Ruptures Experienced Under PT-IP-132-AC,” HW-58281, General Electric, Hanford Atomic Products Operation, Richland, Washington, December 1, 1958, Appendix II.
 R.E. Hall, “Irradiation Summary Report PT-IP-231-A, Irradiation of Depleted Uranium to High Exposure,” HW-62232, October 7, 1959.
 The initial estimate for the plutonium produced in the 84 tubes was the 9 kilograms with a Pu-240 content of 14%. The additional 8 tubes would have produced roughly one additional kilogram. Later analysis showed that the plutonium had a Pu-240 content of 15%. Monthly Record Report, Irradiation Processing Department, January, 1959, HW-59041, February 20, 1959 and “Feature Report: Depleted Uranium Irradiations in the Single-Pass Reactors to Produce High Pu-240 Plutonium,” Monthly Report, September 1968, DUN-4452, Douglas United Nuclear, Inc., Richland Washington, October 16, 1968.
 This material was apparently produced in the Material Testing Reactor, a high power research reactor.
 Hanford Laboratories Operation Monthly Activities Report, November, 1959, HW-62899, General Electric, Hanford Atomic Products Operation, Richland, Washington, December 15, 1959, p. B-12.
 John Cockcroft, “British Experience in the Technical Development of Nuclear Power Reactors,” DPR/INF/261, United Kingdom Atomic Energy Authority, May 1961, p.2.
 The irradiation for one year at the average neutron flux would produce a burnup of about 500 MWD/Te which would have a Pu-240 content of about 4.5%. The maximum burnup would be about 1,000 MWD/Te. The British define weapons grade plutonium as having a Pu-240 content of 8% or less. Any plutonium with a Pu-240 content greater than this is defined as reactor grade. See: “Plutonium and Aldermaston-An Historical Account,” http://www.fas.org/news/uk/000414-uk2.htm Note the British use the term “weapons grade” as opposed to the American “weapon-grade.”
 Hardy H.K., Bishop J.F.W., Pickman D.O., Eldred V.W., “The development of uranium-magnox fuel elements for an average irradiation life of 3000 MWD/te,” Journal of the British Nuclear Energy Society, Vol.2, January 1963, p.40. Though the article was published at the beginning of 1963, the data had to have been from the latter part of 1962.
 J.C.C. Stewart, “Development and Manufacture of Magnox Fuel,” Proceeding of the Institution of Mechanical Engineers, Vol. 178, Part 1, No. 9, 1963-1964, p.238.
 Geoffrey Lean, “DIY Atom Bomb Link to Sellafield,” The Observer, (London), June 6, 1993, p.3.
The only exception is plutonium with a Pu-238 content of 80% or more which is acknowledged to be unusable for the manufacture of nuclear weapons.
Ni nini kilichotumiwa katika jaribio la nyuklia la Marekani la mwaka 1962? "Mwanzoni mwa mwaka wa 1977, Marekani ilifunua kwamba ilikuwa imefanikiwa kupima silaha ya nyuklia mwaka wa 1962 kwa kutumia plutoniamu ya kiwango cha ""reactor.""" Mwaka 1994 taarifa zaidi kuhusu jaribio hilo zilitolewa. Ingawa kwa mtazamo wa kwanza, jaribio hili linaonekana kuamua kwa uhakika suala la kama plutonium ya kiwango cha reactor inaweza kutumika katika silaha za nyuklia, kwa kushangaza, maelezo maalum yanayohusiana na jaribio hili la nyuklia yamezalisha baadhi ya utata zaidi. Mambo machache tu kuhusu jaribio hilo la nyuklia lililofanikiwa yalitolewa. "Mlipuko huo ulifanyika chini ya ardhi katika eneo la majaribio la Nevada, na plutonium iliyotumiwa katika majaribio hayo ilitolewa kwa Marekani na Uingereza chini ya Mkataba wa Ulinzi wa Pamoja wa 1958 kati ya Marekani na Uingereza.""" "Mafunzo hayo yalifanywa kwa lengo la ""kupata habari kuhusu muundo wa nyuklia kuhusu uwezekano wa kutumia plutoniamu ya kiwango cha kiotomatiki kama nyuklia ya kulipuka,"" taarifa ya Idara ya Nishati (DOE) inaendelea kusema, ""Makampuni ya Marekani yana hifadhidata kubwa ya majaribio ya nyuklia na uwezo wa kutabiri.""" Taarifa hii, pamoja na matokeo ya mtihani huu wa uzalishaji wa chini, inaonyesha kwamba silaha zinaweza kujengwa na plutonium ya kiwango cha reactor. <unk> Taarifa hii ya mwisho ni muhimu sana na karibu daima hupuuzwa katika majadiliano kuhusu mtihani huu. "Makubaliano ya Marekani kuhusu matumizi ya plutonium ya kiwango cha reactor kwa ajili ya uzalishaji wa silaha za nyuklia hayategemei majaribio haya tu, bali pia ""database yake nzima ya majaribio ya nyuklia na uwezo wa utabiri ambao umesababisha.""" Kwa hiyo, Marekani haikuhitaji kufanya majaribio ya nyuklia ya plutoniamu ya viwango vyote vya uwezekano wa Pu-240 kujua kwamba silaha za nyuklia zinaweza kutengenezwa kutoka kwa nyenzo kama hiyo. Marekani haijafunua ni jaribio gani la mwaka 1962 ambalo lilitumia plutoniamu ya kiwango cha kiotomatiki. Marekani ilifanya majaribio ya nyuklia zaidi ya miaka yote ya 1962 na 1996. "Hata kama mtu atachagua tu majaribio ambayo nguvu yake inaelezwa kuwa chini ya kiloton 20, na ambayo yalifanywa chini ya ardhi huko Nevada, na ambayo yanahusiana na silaha, mtu atapata kwamba kuna majaribio 36 kama hayo, ya kwanza ilikuwa Januari 30 na ya mwisho ilikuwa Desemba 14.""" Marekani haijafunua kiasi halisi cha plutoniamu ya kiwango cha reactor ya Pu-240 iliyotumiwa katika jaribio hilo. "Kama ilivyoelezwa katika taarifa ya DOE kuhusu jaribio hili, ""katika mwaka wa 1962, plutonium yoyote yenye kiwango cha Pu-240 cha juu kuliko 7% ingekuwa ikionwa kuwa ya kiwango cha kichocheo na kwamba ufafanuzi wa sasa wa viwango vya plutonium zinazotumiwa na DOE na hasa ile ya plutonium ya kiwango cha mafuta (Pu-240 kati ya 7% na 19%) haikutumiwa hadi miaka ya 1970.""" "Kama taarifa ya DOE, ambayo inaonyesha kwamba ni ""reactor-grade plutonium,"" haijulikani ni ipi kati ya ufafanuzi huu wa plutonium inayotumiwa katika jaribio hili." Jambo hilo limewawezesha wengi kudai kwamba plutonium iliyotumiwa katika jaribio hilo ilikuwa ya kiwango cha mafuta badala ya kiwango cha kichocheo. Alexander DeVolpi, mwandishi wa jarida la Physics and Society Newsletter, alidai kuwa kuna udanganyifu wa serikali kuhusu data zilizofichwa kwenye jaribio la 1962. Kulingana na mawasiliano ya kibinafsi kutoka kwa <unk>R.V. Hesketh, anadai kwamba vyanzo vya Uingereza wanadai kwamba plutonium kutumika katika mtihani hakuweza kuwa nini sasa ni kufafanuliwa kama reactor-grade lakini badala yake alikuwa mafuta-grade. "Kama ilivyoelezwa hapo juu, plutonium ya ""reactor"" inaweza kuwa chini ya 81% ya fission, lakini karibu na mpaka wa plutonium ya ""mafuta.""" "Amesema kuwa plutoni hiyo haikuzalishwa nchini Uingereza, lakini ilitolewa nchini Canada na kisha kuhamishwa nchini Uingereza ili kuficha asili yake.""" Karibu wakati huohuo, John Carlson et al. "Kampuni ya Australia ya Safeguards and Non-Proliferation Office (ASNO) imesema kuwa plutonium iliyotumiwa katika jaribio hilo ilikuwa ""ya kiwango cha mafuta"" na ""ya kiwango cha silaha"" na ""ya kiwango cha mafuta"" na ""ya kiwango cha silaha"" na ""ya kiwango cha silaha"" na ""ya kiwango cha mafuta"" na ""ya kiwango cha silaha.""" Katika mwaka wa 2006, ASNO ilichapisha mchoro ambao ulionyesha kuwa imebadilisha maoni yake kwa kiasi fulani kwani sasa inaonyesha plutonium kuwa na uwezekano wa kuwa na maudhui ya Pu-240 kati ya 14% na 18%. karibu mwisho wa kiwango cha reactor ya mbalimbali ya kiwango cha mafuta. "Mwaka 2002, Bruno Pellaud, aliyekuwa naibu mkurugenzi mkuu wa Shirika la Kimataifa la Nishati ya Atomu, alisema kwamba taarifa ya idara ya nishati ya nyuklia ilikuwa ya kupotosha na kwamba plutonium iliyotumiwa katika jaribio hilo ilikuwa ya kiwango cha mafuta na maudhui ya ""Pu-240"" ya 12% tu." Marejeo ya Pellaud kwa madai haya muhimu ni mawasiliano ya kibinafsi kutoka kwa chanzo kisichojulikana. Yeye pia anataja Albright et al. "Mashirika ya Uingereza yalisema kuwa plutoniamu hiyo haingeweza kutokezwa katika mitambo ya kijeshi ya Uingereza ya ""Calder Hall"" na ""Chapelcrost"" kwa sababu ya kiwango cha chini cha mwako." Albright na wenzake wanasema kuwa taarifa ya Marekani ilisababisha mjadala kati ya serikali za Uingereza na Marekani, kwani ilisemekana kuwa nyuklia za Chatterhall na Chapelcrost hazikuwa zikitengeneza plutoniamu ya kiwango cha nyuklia. "Wanaendelea kupinga taarifa hiyo kwa kusema kwamba ""katika kweli Waziri wa Ulinzi wa Uingereza alikuwa amethibitisha taarifa ya Marekani kwa Bunge la Commons.""" Hata hivyo, baada ya kueleza kwa uwazi kwamba plutonium hiyo ilitoka Uingereza, Albright na wenzake waliamua kuifanya. "Mashirika ya kimataifa ya ulinzi yamesema chanzo cha plutoniamu iliyotumiwa katika jaribio hilo la mwaka 1962 hakijulikani na pia haijulikani ikiwa ilitengenezwa nchini Marekani au Uingereza.""" Ingawa wanadai kwamba chanzo cha plutonium ni uhakika sana wanasema <unk> ni [plutonium] alikuwa dhahiri mafuta- badala ya reactor-grade. <unk> Pia ingawa Albright et al. "Kama ilivyoelezwa hapo juu, jaribio hilo linaweza kuwa lilitokea mwishoni mwa mwaka 1962 (majaribio matano kati ya 36 yanayowezekana yaliyotajwa hapo juu yalifanyika Desemba).""" Kwa hiyo, mafuta hayo yangeweza kuwa bado katika mitambo ya Uingereza hadi katikati ya mwaka wa 1962, na bado kungekuwa na wakati wa kutolewa kwa plutoniamu kwa Marekani. Taarifa za kwamba plutoniamu iliyotumiwa katika jaribio la 1962 ilikuwa ya kiwango cha mafuta ya mafuta ni za kawaida. Kwa miaka kadhaa, Shirika la Kimataifa la Nyuklia limedai kwamba plutoni iliyotumiwa katika jaribio hilo ilikuwa na asilimia 85 ya Pu-239. Kwa mfano, Pu-240 ina kiwango cha juu cha mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta. Taarifa kama hizo sasa zinapatikana katika vyanzo kama vile Wikipedia. Kwa nini ni muhimu kujua kiasi cha plutonium ya Pu-240? Je, ni kweli kwamba ni muhimu kwa ajili ya kuimarisha uwezo wa Pu-240 katika mazingira ya hewa, na kwa sababu ya kuwa na uwezo wa kuimarisha uwezo wa Pu-240 katika mazingira ya hewa? Kama ilivyoelezwa hapo juu, lengo la jaribio hili lilikuwa kuthibitisha hesabu za Marekani juu ya matumizi ya plutonium na kiasi cha juu cha Pu-240. Kwa hiyo, hakuna sababu ya sababu ya kutoweza kufikia lengo hili kwa kutumia plutonium na maudhui ya Pu-240 ya 15%. "Watu wengi wanaodai kwamba plutonium iliyotumiwa katika jaribio la 1962 ilikuwa ya kiwango cha mafuta badala ya kiwango cha plutonium cha kiotomatiki pia wanadai kwamba katika miaka yote ya majaribio ya nyuklia hakuna nchi iliyowahi kutumia plutonium ya kiwango cha kiotomatiki katika mlipuko wa nyuklia.""" Taarifa kama hiyo yaonekana kuwa yenye kuvutia lakini kwa kweli ni maneno matupu tu. Kwa kweli, hakuna nchi ambayo imewahi kutumia neptuniamu au uranium-235 iliyotokana na laser kwa silaha ya nyuklia. Hata hivyo, uwezo wa silaha wa vifaa hivi huamuliwa tu na mali zao za nyuklia na za kimwili, sio na ikiwa mtu yeyote amewatumia kabla ya sasa. Hakuna mtu anayetilia shaka kwamba vifaa hivyo vinaweza kutumiwa kutengeneza silaha za nyuklia. Kwa mujibu wa ripoti hiyo, kiwango cha P240, kilichotumiwa katika majaribio ya nyuklia ya mwaka 1962 kilikuwa kati ya asilimia 20 na 23 ya kiwango cha P240. kweli kiwango cha reactor. Ni vigumu sana kusema kwamba ilikuwa chini ya asilimia 12 hadi 14. Kwa mtazamo wa kwanza, ni ajabu kwamba Marekani inahitaji plutonium kutoka Uingereza. Katika miaka ya 1950 na 1960, Marekani ilikuwa na mitambo minane ya kutengeneza plutoniamu katika Hanford, Washington. Ikiwa Marekani inataka plutonium yenye kiwango cha juu cha P240, kwa nini isifanye hivyo? Jibu ni kwamba Marekani ilijaribu lakini ilishindwa. Mwaka 1957 Halford alipokea ombi kutoka kwa Tume ya Nishati ya Atomiki ya Marekani kutengeneza plutonium 11kg yenye kiasi cha 20% cha Pu-240 na kuifanya iwe na uwezo wa kutengeneza plutonium ya kutosha. Hii ilikuwa mara ya kwanza kwa Hanford kutolewa plutonium na kiwango cha juu cha Pu-240 na kutimiza ombi hilo haikuwa jambo la moja kwa moja. Ikiwa Hanford ingekuwa na uranium ya asili ili kukidhi ombi hili, ingehitaji Hanford kutia chini ya mafuta ya uranium ya asili kwa moto wa karibu 3,800 MWdT. Hanford hakuwa amewahi kuchachua uranium ya asili kwa kiwango cha juu cha 1,200-1400 MWd (kiwango cha Pu-240 ni 9%-10%), hii ingehitaji kuchoma kwa karibu mara tatu ya kile kilichokuwa kimefanywa hapo awali. Wenye wasiwasi wa daima kwa waendeshaji wa mitambo ya Hanford walikuwa kuvunjika kwa vipengele vya mafuta ya uranium ya chuma. Mvunjiko ungefunua uranium moto ya chuma kwa maji ya baridi, ikisababisha oxidize na kuvimba ambayo ingekuwa kuzuia njia ya mafuta. Hii inaweza kukata mtiririko wa baridi kwa vipengele vya mafuta katika njia hiyo ya mafuta ambayo katika hali mbaya zaidi itasababisha vipengele hivyo kupasha joto, kukamata moto, na kuweka reactor nzima moto. Kwa hiyo kulikuwa na mifumo ambayo iligundua kutolewa kwa mnururisho wakati kuvunjika kulitokea. Kisha, kichocheo hicho kingelazimika kuzimwa mara moja na sehemu ya mafuta iliyovunjika iondolewe. Katika visa fulani, sehemu ya mafuta ingekuwa tayari imeongezeka vya kutosha hivi kwamba nguvu kubwa ingehitajiwa ili kuiondoa kutoka kwenye kichocheo. Wakati mwingine, kazi hiyo iliharibu sana bomba la alumini lililokuwa na mafuta na maji ya kupoza, hivi kwamba ilibidi liingizwe mahali pengine. Mvunjiko wa mafuta ulikuwa kisababishi kikuu cha kupoteza wakati wa uendeshaji wa kichocheo na hivyo kupoteza uzalishaji wa plutonium. Uwezekano kwamba kipengele cha mafuta ingekuwa kuvunjika kuongezeka juu ya mafuta kuchoma-up. Ili kuepuka matatizo hayo, Hanford aliamua kutumia uranium iliyopunguzwa na kiwango cha U-235 cha 0.15% badala ya kiwango cha asili cha 0.71%. Kutumia uranium hii iliyopunguzwa kwa kiasi kikubwa kungepunguza idadi ya vipande vya mafuta vilivyotokea na ilitumainiwa kupunguza uwezekano wa mafuta kuvunjika. Hanford alikadiria kwamba itahitaji radiation ya karibu 65 hadi 70 tubes (mfereji wa mafuta ya reactor) thamani ya uranium depleted vipengele vya mafuta ya kuzalisha kiasi kinachohitajika cha 20% Pu-240 plutonium. Hanford alitumia vipande 84 vya uranium iliyopunguzwa, ambayo ikiwa ingefanikiwa kabisa ingetengeneza karibu kilo 14 za plutonium na maudhui ya 20% ya Pu-240 katika chombo hicho. Katika tarehe saba tofauti katika mwezi wa Machi, Aprili na Mei 1958 hizi uranium mafuta vipengele walikuwa kubeba katika C reactor. Inakadiriwa kwamba itahitaji miezi 12 hadi 14 ya kutumiwa kwa radiation ili kutengeneza plutonium ya kutosha. Hata hivyo, mnamo Septemba 1958, kulikuwa na mlipuko wa kwanza wa mafuta katika kundi hili la mafuta. Mvunjiko huo ulikuwa mafuta yaliyokuwa yamepakiwa miezi sita tu mapema. Mnamo Oktoba kulikuwa na maporomoko mengine manne na mengine matano mnamo Novemba. Kwa kuongezea kulikuwa na ushahidi kwamba uvimbe katika vipengele vingine vya mafuta ulikuwa ukifanya iwe vigumu kuzisonga katika mfereji wa mafuta. Vitu vyote katika njia zenye vipengele vya mafuta vilivyovunjika au kupanuka viliondolewa. Kufikia wakati huo karibu nusu ya vipengele vya awali vya mafuta vilikuwa vimetolewa. Hanford alitengeneza mirija mingine minane ya vipengele vya mafuta ya uranium iliyopunguzwa kwa kutumia kile kilichotarajiwa kuwa mbinu iliyoboreshwa. Vifaa hivyo vilitengenezwa na vifaa vya kutengeneza mafuta vilivyowekwa kwenye kiwanda cha C katika mwaka wa 1958. Kulikuwa na mlipuko wa ziada katika mafuta ya awali yaliyopunguzwa mnamo Desemba na mbili zaidi mnamo Januari ambazo zilikuwa na tofauti ya siku mbili tu. Matokeo yakawa kwamba mafuta yote yaliyobaki ya awali ya uranium iliyopunguzwa yaliangushwa. Mlipuko wa mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta. Ilitambuliwa kwamba uboreshaji katika vipengele hivi vipya vya mafuta ulikuwa mdogo tu. Baada ya miaka miwili, Hanford alilazimika kukubali kushindwa na hakukuwa na juhudi zaidi za kuzalisha plutonium ya juu ya Pu-240 hadi 1964. Hata hivyo, kwa sasa, ni vigumu kupata plutonium ya kiwango cha juu cha 15%, na kiwango cha juu cha plutonium ya kiwango cha juu cha 15%. Matokeo ya kushindwa huko yalikuwa ya mara moja. Hanford alikuwa anatarajia kupokea kutoka Oak Ridge usafirishaji wa 1.2kg ya plutonium na maudhui ya Pu-240 ya 20%. Plutoniamu hiyo ilipaswa kutumiwa katika Kiwanda cha Majaribio cha Viwango vya Fizikia. Hata hivyo, Hanford aliiarifiwa kwamba haingepokea nyenzo hii kwa sababu <unk>The Division of Military Applications<unk> alikuwa amefanya <unk>madai ya awali<unk> juu ya nyenzo hii. Utafiti wa Hanford ulionyesha kuwa plutonium yenye kiwango cha juu cha P240, ilikuwa nadra sana. Sasa ni wazi kwa nini Marekani ililazimika kuwaendea Waingereza kwa msaada. Lakini ni kwa nini Uingereza ilipata plutoniamu yenye kiasi kikubwa cha Pu-240? Uingereza ina nyuklia nane za kutengeneza plutonium, nne katika Calder Hall na nne katika Chapel Cross, ambazo zinaendeshwa na Mamlaka ya Nishati ya Atomiki ya Uingereza. Kama vile nyuklia za Marekani huko Hanford, nyuklia hizi nane zilitumia graphite kama moderator lakini tofauti na nyuklia za Marekani zile za Uingereza zilitengenezwa kuzalisha umeme pia. "Hakuna chanzo cha Uingereza ambacho kinasema jinsi mafuta yalivyotumiwa katika mitambo hiyo yalivyotumiwa katika miaka ya 1950 na mapema miaka ya 1960, lakini inaonekana kwamba mafuta hayo yalitumiwa kwa muda wa mwaka mmoja tu, na ni rahisi kuhesabu kwamba kipindi hicho cha kutumiwa kwa umeme kilitokeza ""moto"" wa kiwango cha juu cha 1,000 MWdT, na hivyo kutokeza plutoni yenye kiwango cha chini cha P240.""" Plutonium ya kiwango cha silaha ya Uingereza. Kwa kuwa inajulikana kwamba kazi kuu ya mitambo hiyo wakati huo ilikuwa kutengeneza plutoniamu ya kutumiwa kutengeneza silaha, hilo halishangazi. Uingereza pia ilikuwa ikijenga mfululizo wa mitambo ya umeme ambayo ingeendeshwa na Bodi ya Kati ya Uzalishaji wa Umeme (CEGB). Reactors hizi zilikuwa ni toleo kubwa la Calder Hall na Chapel Cross reactors lakini kazi yao ilikuwa kuzalisha umeme ambayo kwa sababu za kiuchumi ilimaanisha kwamba wangejaribu kufikia kiwango cha juu cha mafuta ya kuchoma. Wakati wa kuanza kazi ya mitambo hii, ilidhaniwa kwamba mafuta yanaweza kufikia wastani wa 3000 MWdT (kiwango cha Pu-240 ni karibu 17%) na matumaini kwamba inaweza kufikia 5000 MWdT (kiwango cha Pu-240 ni karibu 25%). Hata hivyo, nyuklia mbili za kwanza (Berkeley 1 na Bradwell 1) zilianza kufanya kazi katika majira ya joto ya 1962. Kwa kuwa itatumia karibu mwaka mmoja kwa mitambo hii kutengeneza plutonium yenye kiwango cha Pu-240 cha zaidi ya 8%, ni wazi kwamba mitambo hii haikuwa chanzo cha plutonium kwa ajili ya jaribio la 1962. Kwa mtazamo wa kwanza, kwa hivyo, wala mitambo ya uzalishaji wa plutonium wala mitambo ya umeme ya kiraia haingeweza kuwa chanzo cha plutonium kwa jaribio la 1962. Suluhisho la fumbo hili la kuonekana ni kwamba ingawa kazi ya msingi ya mitambo ya Calder Hall na Chapelcross ilikuwa kutengeneza plutonium ya kiwango cha silaha, haikuwa kazi yao pekee. Kwa mfano, wakati wa kuanzishwa kwa mitambo ya umeme ya CEGB, kulikuwa na haja ya kupima mafuta ambayo yangetumika katika mitambo hii ili kuona kama wangeweza kufikia moto wa juu wa kutosha kufanya mitambo hii iwe na uchumi. Ni mahali gani bora pa kujaribu mafuta kama hayo kuliko katika mitambo ya Calder Hall na Chapel Cross ambayo kwa kweli ilikuwa sawa katika muundo katika mitambo mpya ya CEGB? Hii ilikuwa hasa hivyo tangu U.K.A.E.A. Mfumo wa CEGB, ambao ni moja ya mitambo ya msingi ya CEGB, unatoa mafuta kwa ajili ya mitambo ya CEGB. Hardy na wenzake, kuandika katika sehemu ya mwisho ya 1962, walionyesha kwamba kama sehemu ya programu ya majaribio ya juu ya burnup katika Calder Hall na Chapelcross reactors, wastani wa burnups ya channel ya zaidi ya 3,000 MWdT ilikuwa imefikiwa. Kwa mfano, kiwango cha moto cha msingi cha mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta. Calder Hall na Chapelcross reactors kutumika sita vifaa vya mafuta kwa kila mfereji wa mafuta. Kwa kutenganisha vipengele viwili vya mafuta kutoka kwa njia za mafuta, mtu anaweza kupata plutonium na maudhui ya Pu-240 ya 23%. Mtu angeweza kurudia mara mbili kiasi cha plutonium kilichopatikana ikiwa elementi nne za msingi za mafuta zingefanyiwa kazi pamoja. Plutonium iliyotokezwa kwa njia hiyo ilichanganyika na kuwa na kiasi cha Pu-240 cha karibu 20%. "Kama ilivyoelezwa katika makala ya ""Mean and Peak Fuel Burnup"" ya Stewart, kiwango cha mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta." "Kutumia data ya ""mzunguko"" wa miaka ya 1962 na 1962 na ""mzunguko"" wa miaka ya 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962 na 1962." Sasa ni wazi kwa nini Marekani ilikaribia Uingereza kwa msaada. Kwa mujibu wa ripoti hiyo, ni kiasi gani cha plutonium iliyotumiwa katika majaribio ya mwaka 1962 ya Marekani? "J. Carson Mark, aliyekuwa mkuu wa idara ya nadharia ya Los Alamos kutoka mwaka wa 1947 hadi 1972, alisema kwamba ""mtihani wa 1962 ulitumia plutoniamu yenye kiasi cha juu zaidi cha Pu-240.""" Kwa kuwa Marekani tayari ilizalisha plutonium yenye kiasi cha 15% cha Pu-240, Pellaud, Carlson na wenzake wanadai kwamba ni ya kutosha kwa ajili ya matumizi ya nyuklia. Kwa mujibu wa shirika la kimataifa la nyuklia la World Nuclear Association (WNA), plutoniamu hiyo ina kiasi cha asilimia 12 ya madini ya urethane, ambayo ni asilimia 14 ya madini ya urethani. Kwa kuongezea, Pu-240 ilikuwa na kiwango cha juu cha 15% ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta ya mafuta. Kwa mfano, kiwango cha juu cha Pu-240 kilichopatikana kutoka Uingereza kilikuwa kati ya 20% na 23%. "Kwa kuzingatia kile Mark amesema kuhusu kutumia kiwango cha juu cha Pu-240 inapatikana, ni uwezekano mkubwa kwamba ""20% hadi 23%"" mbalimbali inawakilisha kile kilichotumiwa katika mtihani wa 1962." Kwa mujibu wa taarifa ya kampuni ya Hanford, kiwango cha awali cha Pu-240 kilikuwa 20%. "Hata hivyo, katika taarifa ya mwaka 1959 ya shirika la Hanford, ilisema kwamba ""siwezi kukataa kupokea plutoniamu ya kilo 1.2 yenye kiasi cha 20% ya P240, kwa sababu idara ya matumizi ya kijeshi ilikuwa imetoa madai ya awali juu ya plutoniamu hiyo.""" Kwa hivyo, licha ya taarifa nyingi kinyume chake, inaonekana kwamba plutonium katika jaribio la 1962 ilikuwa ya kiwango cha reactor baada ya yote, hata kwa ufafanuzi wa sasa unaohitaji nyenzo kama hiyo kuwa na maudhui ya Pu-240 ya angalau 19% na ilikuwa uwezekano mkubwa katika safu ya 20% hadi 23% ya Pu-240 "Hakuna shaka kwamba kuna watu ambao watasema kwamba hata kama jaribio la 1962 lilitumia plutonium na maudhui ya Pu-240 ya 20% au 23%, plutonium iliyotolewa kutoka kwa mitambo ya sasa ina maudhui ya juu ya Pu-240 (sawa na zaidi ya 30%) na kwamba nyenzo kama hiyo haijawahi kupimwa katika silaha ya nyuklia. """ Ingawa taarifa kama hiyo ingekuwa kweli, inapuuza hatua iliyojadiliwa hapo juu ambayo inafaa kurudia: <unk> Marekani inadumisha hifadhidata kubwa ya majaribio ya nyuklia na uwezo wa utabiri. "Hii taarifa pamoja na matokeo ya majaribio ya nguvu ya chini, inaonyesha kwamba silaha inaweza kuwa kujengwa na plutonium reactor-grade. taarifa za Marekani kuhusu matumizi ya plutonium reactor-grade kwa ajili ya uzalishaji wa silaha za nyuklia si msingi tu juu ya majaribio ya nyuklia ya 1962 lakini badala yake database yake nzima ya majaribio ya nyuklia na uwezo wa utabiri kwamba wamekuwa matokeo. """ Kwa hiyo, Marekani haikuhitaji kufanya majaribio ya nyuklia ya plutoniamu ya viwango vyote vya uwezekano wa Pu-240 kujua kwamba silaha za nyuklia zinaweza kutengenezwa kutoka kwa nyenzo kama hiyo. "Mwanzoni mwa miaka ya 1960, Robert W. Selden, mtengenezaji wa silaha za nyuklia wa Marekani, alisema: ""Wazo la ""denaturated"" plutonium (Pu ambayo si sahihi kwa ajili ya nyuklia) ni makosa.""" "Madai ya kwamba jaribio la nyuklia la 1962 lilikuwa la ""kitovu cha plutonium"" badala ya ""kitovu cha nyuklia"" ni mfano mmoja tu wa hoja za uwongo zinazotumiwa." Wengine wametumia mahesabu ya uwezekano wa silaha predetonation au uchambuzi wa joto ya silaha kujaribu kujadili uhakika huu huo. "Hata hivyo, uchunguzi huo pia una kasoro, na Marekani imeeleza wazi kwamba licha ya nyuklia ya nyuklia ya kiwango cha juu zaidi au nyuklia ya kiwango cha juu zaidi ya nyuklia ya kiwango cha nyuklia, nyuklia hiyo inaweza kutumiwa kutengeneza silaha za nyuklia zenye kuharibu.""" Ni wakati wa ukweli huu mgumu kutambuliwa kwa ujumla. Mwandishi ana ushirika mbalimbali. Karatasi hii ilitengenezwa kwa ajili ya Kituo cha Elimu ya Sera ya Usimamizi wa silaha za nyuklia. Ingawa mwandishi ni pia sehemu ya muda msaidizi mfanyakazi katika RAND Corporation, karatasi hii haina uhusiano na mradi wowote RAND na RAND haina jukumu kwa yoyote ya uchambuzi na maoni yaliyoelezwa katika yake. Nukuu zote katika kifungu hiki ni kutoka Ibid. Kwa sasa, Marekani inaamua kuwa plutonium ya silaha ina kiwango cha chini cha 7% cha Pu-240 katika nyenzo zake. "Plutonium ya kiwango cha mafuta ina maana ya ""Putonium ya kiwango cha mafuta"" na ""Putonium ya kiwango cha mafuta"" ina maana ya ""Putonium ya kiwango cha mafuta"" na ""Putonium ya kiwango cha mafuta"" na ""Putonium ya kiwango cha mafuta"" na ""Putonium ya kiwango cha mafuta"" na ""Putonium ya kiwango cha mafuta"" na ""Putonium ya kiwango cha mafuta"" na ""Putonium ya kiwango cha mafuta.""" "Plutonium: The First 50 Years, DOE, DEP-0137, U.S. Department of Energy, Februari 1996, ukurasa wa 17.""" A. Devolpi, <unk>A Coverup of Nuclear Test Information?<unk> Physics and Society newsletter, Vol. 25 No. 4, Oktoba 1996. John Carlson, John Bardsley, Victor Bragin, John Hill, <unk>Plutonium Isotopics<unk>Nonproliferation and Safeguards Issues,<unk> Australia Safeguards Office, IAEA-SM-351-64. "Plutonium ya Reactor-Grade: Matumizi katika Majaribio ya Silaha, "" ASNO Information Sheet, Desemba 2006 (iliyorekebishwa Agosti 2008)." "Bruno Pellaud, ""Proliferation aspects of plutonium recycling,"" Journal of the Institute of Nuclear Material Management, Fall 2002, p. 3." David Albright, Frans Berkhouwer na William Walker, Pluto na Uranium ya Utajiri wa Juu: Hifadhi ya Dunia, Uwezo na Sera, SIPRI, Oxford University Press, 1997, p. 61-62 - Mfano wa Usalama "Forrest alisema kwamba majaribio ya nyuklia ya ""Tendrake"" ya Desemba 7, 1962 yalikuwa ya pamoja na Marekani na Uingereza, na kwamba ""hiyo inaweza kuwa tarehe ya majaribio.""" "Eric Forrest, ""Kuchunguza hatari ya kuenea kwa plutonium ya kiwango cha reactor,"" Massachusetts Institute of Technology, Fall 2010, p. 7 na ""Mtihani wa nyuklia wa Marekani, Julai 1945 hadi Septemba 1992,"" DOE, N.V.R.V. 15, Idara ya Nishati ya Marekani, Ofisi ya Uendeshaji ya Nevada, Desemba 2000, p. 27." Tazama: J.M. Kay, C.G. James, K. Saddington, na C. J. Turner, <unk>Chemical michakato, <unk> Jarida la Uingereza Nishati ya Nyuklia Mkutano, Vol. Nambari ya nne. Aprili 2, 1959 (p. Ikiwa, kwa mfano, mafuta yalichukuliwa tarehe 30 Juni 1962, basi kungekuwa na muda wa kutosha (siku 60) kwa plutonium iliyogawanywa kusafirishwa kwenda Marekani na kutengenezwa kwa ajili ya majaribio ya Desemba 7. "Mwaka wa 1968: ""Urania iliyopunguzwa na mnururisho katika Reactors ya Kupita Moja ili Kuzalisha Plutonium ya Pu-240 ya Juu"" (Dun-U-2452 Douglas, Inc., Richland, Washington, DC, Oktoba 16, 1968) " Utafiti wa U.S.A.C. ulionyesha kwamba kwa miaka mingi, kampuni ya Hanford haijawahi kuambiwa kwa nini ilihitaji kutengeneza nyenzo yoyote ya kiwanda cha nyuklia. Kila chombo kilikuwa na vifaa 36 vya kuchochea. 26 kati ya hizo zilikuwa za uranium iliyopunguzwa, 10 nyingine zilikuwa za uranium ya asili. Mpangilio huu "ulilenga" elementi zilizopungua katika eneo lenye mtiririko wa juu wa neutroni. W.A. "Blanton, ""I & E Depleted Uranium Fuel Element Ruptures Experienced Under PT-IP-132-AC"" (HW-58281) ni ripoti ya utafiti wa hali ya hewa ya Marekani iliyochapishwa na kampuni ya General Electric, Hanford Atomic Products, Richland, Washington, Desemba 1, 1958." R.E. "Halley, ""Irradiation Summary Report PT-IP-231-A, Irradiation of Depleted Uranium to High Exposure"" (HW 62232 Oktoba 7, 1959)." Kwa mujibu wa makadirio ya awali, plutonium iliyotengenezwa katika mabomba hayo 84 ilikuwa kilo 9 na kiasi cha Pu-240 kilikuwa asilimia 14. Vipande hivyo 8 vya maji vilikuwa vimeongeza uzito wa mwili kwa kilo moja. Uchunguzi wa baadaye ulionyesha kwamba plutonium ilikuwa na maudhui ya Pu-240 ya 15%. "Mwaka wa 1959: ""Mwezi Ripoti ya Rekodi,"" Idara ya Maendeleo ya Irradiation, HW-59041, Februari 20, 1959 na ""Mwaka Ripoti: Uharibifu wa Uranium katika Reactors ya Kupita Moja ili Kuzalisha Pu-240 Plutonium,"" Ripoti ya Kila Mwezi, Septemba 1968, DUN-4452, Douglas United Nuclear, Inc., Richland, Washington, Oktoba 16, 1968." Yaonekana nyenzo hiyo ilitengenezwa katika Reaktor ya Majaribio ya Vifaa, ambayo ni kiwanda cha utafiti chenye nguvu nyingi. "Hatari ya Uendeshaji wa Halmashauri ya Hanford, Novemba 1959, HW-62899, ""General Electric,"" Hanford Atomic Products, Richland, Washington, Desemba 15, 1959, p. 12." "John Cockcroft, ""Uzoefu wa Uingereza katika Maendeleo ya Ufundi wa Vifaa vya Nishati ya Nyuklia"" (DEPRINF 261, Mamlaka ya Nishati ya Atomiki ya Uingereza, Mei 1961), p." Kwa mfano, kwa mwaka mmoja, mionzi ya nyuklia ya kiwango cha wastani cha neutron ingesababisha moto wa karibu 500 MWdT, ambayo ingekuwa na maudhui ya Pu-40. Kiwango cha juu cha moto ni karibu 1000 MW. "Mashirika ya silaha ya Uingereza yanaelezea ""kiwango cha silaha"" cha plutonium kama kuwa na kiwango cha ""kiwango cha silaha"" cha plutonium ya Pu-240 ya 8% au chini." Plutonium yoyote yenye kiwango cha Pu-240 zaidi ya hii hufafanuliwa kama kiwango cha kichocheo. "Kama ilivyoelezwa katika makala ya ""Ukanda wa Uharibifu wa Nyuklia"" ya The Guardian, ""Ukanda wa Uharibifu wa Nyuklia"" ni ""Ukanda wa Uharibifu wa Nyuklia"" na ""Ukanda wa Uharibifu wa Nyuklia"" ni ""Ukanda wa Uharibifu wa Nyuklia"" na ""Ukanda wa Uharibifu wa Nyuklia"" ni ""Ukanda wa Uharibifu wa Nyuklia"" na ""Ukanda wa Uharibifu wa Nyuklia"" ni ""Ukanda wa Uharibifu wa Nyuklia"" na ""Ukanda wa Nyuklia"" ni ""Ukanda wa Nyuklia.""" Ingawa makala hiyo ilichapishwa mwanzoni mwa mwaka wa 1963, ni lazima habari hizo ziwe zilitoka mwishoni mwa mwaka wa 1962. J.C.C. Stewart, <unk>Mwanzo na Utengenezaji wa Magnox Fuel, <unk> Majaribio ya Taasisi ya Wahandisi wa Mashine, Vol. 178, sehemu ya 1, No. (Mdo. 9:33-37) Kwa nini? "Jeffrey Lean, ""DIY Atomic Bomb Link to Sellafield,"" The Observer, (London), Juni 6, 1993, ukurasa wa 3." Plutonium yenye kiwango cha Pu-238 cha 80% au zaidi haitumiki kwa ajili ya kutengeneza silaha za nyuklia.