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ABSTRACT
The claim that reactor-grade plutonium cannot or will not be used to produce nuclear weapons has been used to justify non-nuclear-weapon states’ large stockpiles of plutonium that has been separated from highly radioactive spent fuel. However, by using reduced-mass plutonium cores, it is possible to manufacture reliable nuclear weapons with reactor-grade plutonium. These weapons can have the same design, size, weight, and predetonation probability as weapons using weapon-grade plutonium and would require no special cooling. The increased radiation from reactor-grade plutonium could be easily managed by shielding and operational procedures. Weapons using plutonium routinely produced by pressurized-water reactors could have a lethal area between 40 percent and 75 percent that of weapons using weapon-grade plutonium. In the past, both Sweden and Pakistan considered using reactor-grade plutonium to produce nuclear weapons, and India may be using reactor-grade plutonium in its arsenal today. Despite claims to the contrary, the United States used what was truly reactor-grade plutonium in a successful nuclear test in 1962. The capability of reactor-grade plutonium to produce highly destructive nuclear weapons leads to the conclusion that the separation of plutonium, plutonium stockpiling, and the use of plutonium-based fuels must be phased out and banned.
Disclosure statement
No potential conflict of interest was reported by the author.
Notes
1 “Global Fissile Material Report 2015, Nuclear Weapon and Fissile Material Stockpiles and Production,” International Panel on Fissile Material, 2015, p. 25, <http://fissilematerials.org/library/gfmr15.pdf>.
2 David Albright, Serena Kelleher-Vergantini, and Daniel Schnur, “Civil Plutonium Stocks Worldwide, End of 2014,” Institute for Science and International Security, November 16, 2015, p. 4, <https://isis-online.org/uploads/isis-reports/documents/Civil_Plutonium_Stocks_Worldwide_November_16_2015_FINAL.pdf>.
3 The issue of terrorists manufacturing nuclear weapons is not addressed in this article. Whether terrorists can produce nuclear weapons is highly uncertain and not very dependent on the type of plutonium that they might attempt to use.
4 G. Kessler, Proliferation-Proof Uranium/Plutonium Fuel Cycles: Safeguards and Non-Proliferation (Karlsruhe, Germany: KIT Scientific Publishing, 2011), <www.ksp.kit.edu/9783866446144>. He has produced an expanded version of the book: G. Kessler, Proliferation-Proof Uranium/Plutonium and Thorium/Uranium Fuels Cycles (Karlsruhe, Germany: KIT Scientific Publishing, 2017), <www.ksp.kit.edu/9783731505167>.
5 “The Status Report of Plutonium Management in Japan—2017,” Japan Office of Energy Policy, July 31, 2018, <www.aec.go.jp/jicst/NC/about/kettei/180731_e.pdf>.
6 “Fake Story: Japan Has Plutonium Enough to Make 6,000 Bombs,” Plutonium, No. 86 (2018), p. 21, <www.cnfc.or.jp/pdf/Plutonium86E.pdf>.
7 “The Basic Principles on Japan’s Utilization of Plutonium,” Japan Atomic Energy Commission, July 31, 2018, <www.aec.go.jp/jicst/NC/iinkai/teirei/3-3set.pdf>.
8 Troy Stangarone, “Is Trump Right to Suggest that South Korea and Japan Should Go Nuclear?” Korea Economic Institute of America, April 2016, <http://keia.org/trump-right-suggest-south-korea-and-japan-should-go-nuclear>.
9 The significance of these properties of plutonium is discussed in more detail below.
10 Stephen Farrell, “Israel Admits Bombing Suspected Syrian Nuclear Reactor in 2007, Warns Iran,” Reuters, March 20, 2018, <www.reuters.com/article/us-israel-syria-nuclear/israel-admits-bombing-suspected-syrian-nuclear-reactor-in-2007-warns-iran-idUSKBN1GX09K>.
11 Mark Hibbs, “U.S. to Ask New Delhi to Back off on Research Reactor Offer to Iran,” Nucleonics Week, November 21, 1991, pp. 2–3.
12 Assumes the reactor operates at 80 percent capacity, fuel full burnup is 37,000 MWD/Te, and the fuel will contain about 10 kilograms of plutonium per metric ton.
13 “Saudi Crown Prince Says Will Develop Nuclear Bomb if Iran Does: CBS TV,” Reuters, March 15, 2018, <www.reuters.com/article/us-saudi-iran-nuclear/saudi-crown-prince-says-will-develop-nuclear-bomb-if-iran-does-cbs-tv-idUSKCN1GR1MN>.
14 Samuel Glasstone and Alexander Sesonske, Nuclear Reactor Engineering (New York: D. Van Nostrand Company, 1963), p. 488.
15 “Plutonium: The First 50 Years,” DOE/DP-0137, United States Department of Energy, February 1996, p. 17, <www.osti.gov/opennet/servlets/purl/219368/219368.pdf>.
16 Gregory S. Jones, “Reactor-Grade Plutonium and Nuclear Weapons: Exploding the Myths,” Nonproliferation Policy Education Center, 2018, Appendix, <https://nebula.wsimg.com/3fd1e3cfbbf101d6c4f562e17bc8604c?AccessKeyId=40C80D0B51471CD86975&disposition=0&alloworigin=1>.
17 Ibid.
18 For example, in 1963, non-weapon-grade plutonium was defined as having a Pu-240 content of higher than 7.7 percent. L.W. Lang and W.J. Dowis, “K and N Reactor Capabilities,” HW-78650, August 16, 1963, General Electric, Richland, WA, p. 8, <www.osti.gov/servlets/purl/10146304>.
19 In justifying this production of high Pu-240 plutonium, Hanford said, “At present, however, much of the plutonium which is available for fast reactors, of both prototypical and research types, has only a very low Pu-240 content.” See “Monthly Report,” Douglas United Nuclear Inc., DUN-1640, Richland, WA, December 1966, p. C-1, <www.osti.gov/servlets/purl/64014>.
20 The earliest official reference that the Congressional Research Service could find to the current classification system was a congressional hearing in 1981. See Justin L. Bloom, “Plutonium Grade and the Risk of Nuclear Weapons Proliferation: A Review of Thinking on a Troublesome Subject,” Congressional Research Service, August 1985, p. 18.
21 D.O. Campbell and E.H. Gift, “Proliferation-Resistant Nuclear Fuel Cycles,” Oak Ridge National Laboratory, ORNL/TM-6392, Department of Energy, June 1978, <www.osti.gov/servlets/purl/6743129>.
22 The plutonium isotopes Pu-238 and Pu-241 have half-lives short enough to decay significantly if the plutonium is stored for many years. The plutonium characteristics in are for plutonium that has decayed for ten years after discharge from the nuclear reactor. Some plutonium is already as much as forty years old. For such plutonium, the decay heat would be somewhat decreased and the spontaneous fission neutrons somewhat increased. See Jones, “Reactor-Grade Plutonium and Nuclear Weapons,” p. 53.
23 Strictly speaking, only 28 of the reactors were MAGNOX. The other ten were French “uranium naturel-graphite-gaz” but the designs were very similar.
24 For CANDU reactors, see M.S. Milgram & K.N. Sly, “Tables of the Isotopic Composition of Transuranium Elements Produced in Canadian D2O Moderated Reactors,” Atomic Energy of Canada Limited, AECL-5904, Chalk River Nuclear Laboratories, Chalk River, ON, August 1977, p. 18, <www.iaea.org/inis/collection/NCLCollectionStore/_Public/09/360/9360944.pdf>. For Magnox reactors, see “NDA Plutonium Options,” Nuclear Decommissioning Authority, UK, 2008, p. 19, <https://tools.nda.gov.uk/publication/plutonium-options-for-comment-august-2008/>.
25 PWR 33,000 MWD/Te and PWR 51,000 MWD/Te: see Brent Dixon and Roald Wigeland, “The Impact of Burnup on the Performance of Alternative Fuel Cycles,” GNEP-SYSA-AI-NE-RT-2008-000252, April 28, 2008. PWR 20,000 MWD/Te is from an Origen 2 run performed by the author.
26 Based on GC-859 database. Personal communication, John Scaglione and Kaushik Banerjee, Oak Ridge National Laboratory.
27 Fuel aged to ten years after discharge. See Yashar Rahmani, Ali Pazirandeh, Mohammad B. Ghofrani, and Mostafa Sadighi, “Calculation of the Fuel Composition and the Thermo-neutronic Parameters of the Bushehr’s VVER-1000 Reactor during the Initial Startup and the First Cycle Using the WIMSD5-B, CITATION-LDI2 and WERL codes,” Annals of Nuclear Energy, Vol. 57 (2013), pp. 68–83, <https://ac.els-cdn.com/S030645491200463X/1-s2.0-S030645491200463X-main.pdf?_tid=265afa87-895d-42db-b110-52cdbd488ddf&acdnat=1539107995_47ac68425544f3db1f9c01078a4fe753>.
28 G. Youinou and S. Bays, “A Neutronic Analysis of TRU Recycling in PWRs Loaded with MOX-UE Fuel (MOX with U-235 Enriched Support),” AFCI-SYSA-TRAN-SS-RT-2009-000055, Idaho National Laboratory, US Department of Energy, May 2009, p. 40, <https://inldigitallibrary.inl.gov/sites/sti/sti/4282336.pdf>.
29 Kosaku Fukuda, Hiroshi Sagara, Masaki Saito, and Tsunetomo Mitsuhashi “Feasibility of Reprocessed Uranium in LWR Fuel Cycle for Protected Plutonium Production,” Journal of Nuclear Science and Technology, Vol. 45, No. 10, October 2008, p. 1,019, fuel aged to ten years, <www.tandfonline.com/doi/pdf/10.1080/18811248.2008.9711887?needAccess=true>.
30 France, the only country to recycle uranium in a significant way, stopped producing fuel using this uranium in 2012, in part because the French utility (EDF) objected to the high cost. See International Panel on Fissile Materials, “Plutonium Separation in Nuclear Power Programs,” July 2015, p. 34. <http://fissilematerials.org/library/rr14.pdf>.
31 “Plutonium,” World Nuclear Association, updated October 2017, <www.world-nuclear.org/information-library/nuclear-fuel-cycle/fuel-recycling/plutonium.aspx>. These claims have been on the website since at least 2009.
32 In a subcritical mass of HEU or plutonium, if neutrons are introduced, more neutrons are lost leaking outside of the material than are produced by fission and the chain reaction dies out. The compression of the nuclear material causes its surface area to decrease, reducing the number of neutrons lost to leakage. When the number of neutrons lost is equal to the number produced by fission, the system is critical. As the surface area continues to decrease, the system becomes supercritical. More neutrons are produced by fission than are lost to leakage and the number of neutrons increases exponentially, resulting in a nuclear explosion.
33 Samuel Glasstone and Leslie M. Redman, “An Introduction to Nuclear Weapons,” WASH-1037, US Atomic Energy Commission, June 1972, pp. 26–32, originally SECRET, now UNCLASSIFIED but heavily redacted, <http://fissilematerials.org/library/aec72.pdf>.
34 “Restricted Data Declassification Decisions 1946 to the Present,” RDD-8, US Department of Energy, January 1, 2002, p. 76, <https://fas.org/sgp/othergov/doe/rdd-8.pdf>.
35 The former nuclear-weapon designer Theodore Taylor explained the basic concept of “levitation” (though he did not use the term) by saying, “When you hammer a nail, what do you do? Do you put the hammer on the nail and push?” John McPhee, The Curve of Binding Energy (New York: Farrar, Straus & Giroux, 1974), p. 218.
36 The first French nuclear test used a device that weighed only about one-third that of the Nagasaki weapon yet produced over triple the yield with a plutonium core. The first Chinese test used a device that weighed only about one-third that of the Nagasaki weapon yet produced about the same yield with an HEU core. See Robert S. Norris and Hans M. Kristensen, “Nuclear Pursuits, 2012,” Bulletin of the Atomic Scientists, 2012, p. 97, <https://journals.sagepub.com/doi/pdf/10.1177/0096340211433025>.
37 The Nagasaki weapon was 5 feet in diameter. In contrast, the Iranian design was only about 2 feet in diameter and could be carried on a Shahab-3 ballistic missile. The Iranian nuclear-weapon design is shown from 5:45 to about 7:35 in “Presentation of Israeli Prime Minister Benjamin Netanyahu,” April 30, 2018, <www.c-span.org/video/?444882-2/prime-minister-netanyahu-iran-nuclear-agreement>.
38 Albert Wohlstetter, “Spreading the Bomb without Quite Breaking the Rules,” Foreign Policy, No. 25 (1976–77), pp. 160–61, <www.npolicy.org/userfiles/file/Nuclearpercent20Heuristics-Spreadingpercent20thepercent20Bombpercent20withoutpercent20Quitepercent20Breakingpercent20thepercent20Rules.pdf>.
39 H.C. Paxton, “Los Alamos Critical Mass Data,” Los Alamos Scientific Laboratory, LAMS-3067, April 1964, p. 45, <https://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-03067-MS>.
40 R.O. Gumprecht, “Plutonium Production Quality,” General Electric, Richland, WA, HW-31952, May 28, 1954, p. 3, <www.osti.gov/servlets/purl/87792>.
41 J. Carson Mark, “Explosive Properties of Reactor-Grade Plutonium,” Science and Global Security, Vol. 4 (1993), p. 120, <http://scienceandglobalsecurity.org/archive/sgs04mark.pdf>.
42 J. Carson Mark, “Reactor-Grade Plutonium’s Explosive Properties,” Nuclear Control Institute, August 1990, pp. 3–5, <www.nci.org/new/NT/rgpu-mark-90.pdf>.
43 Victor Gilinsky, Marvin Miller, and Harmon Hubbard, “A Fresh Examination of the Proliferation Dangers of Light Water Reactors,” Nonproliferation Policy Education Center, October 22, 2004, Appendix 3, <www.iranwatch.org/sites/default/files/perspex-npec-lwr-102204.pdf>.
44 Recall that General Groves was willing to accept a 20 percent probability of predetonation.
45 For yields of 5 kilotons and above, the lethal area is determined by the blast effects, which scale with the two-thirds power of the yield. Below a yield of 5 kilotons, the lethal area is determined by the initial nuclear radiation, which declines much less rapidly as the yield is reduced and must be calculated directly. See Samuel Glasstone and Philip J. Dolan, The Effects of Nuclear Weapons, 3rd edn.(Washington, DC: US Department of Defense and US Department of Energy, 1977).
46 Since the 16-kiloton Hiroshima weapon had a lethal area of about 8 square kilometers, even a 0.7-kiloton weapon would have a lethal area of almost 2 square kilometers. A number of major cities such as New Delhi, Seoul, and Tokyo have central population densities of 10,000 per square kilometer or more.
47 Lorna Arnold, Britain and the H-Bomb (Basingstoke, UK, and New York, NY: UK Ministry of Defense, Palgrave, 2001), p. 177.
48 “Reactor-Grade Plutonium,” Wikipedia, <https://en.wikipedia.org/wiki/Reactor-grade_plutonium>.
49 Mark, “Reactor-Grade Plutonium’s Explosive Properties,” pp. 3–4.
50 All solid metals have a crystalline structure. For many solid metals, changing the temperature can lead to changes in the crystalline structure. These different structures of the same metal are known as “allotropes.” By convention, the different allotropes are designated by Greek letters, alpha being the lowest-temperature allotrope, beta the next-highest-temperature allotrope, and so on. The different allotropes can have significantly different physical properties. Plutonium has six allotropic forms, the most of any metal. W.N. Miner and F.W. Schonfeld, “Physical Properties,” in O. J. Wick, ed., Plutonium Handbook, Vol. 1, (New York, London, and Paris: Gordon and Breach, Scientific Publishers, 1967), pp. 33–34.
51 Jones, “Reactor-Grade Plutonium and Nuclear Weapons,” p. 75.
52 G. Kessler, Proliferation-Proof Uranium/Plutonium Fuel Cycles, p. 265. Kessler states that a plutonium core with a total heat output of 120 watts would begin to melt World War II-type explosives. Though he is not explicit, it appears he is referring to a core that contains 9.24 kilograms of plutonium.
53 In 2020, the United Kingdom’s total stockpile of separated plutonium will be 120 metric tons. Of this, about 85 metric tons will have been produced in Magnox reactors and the remaining 35 metric tons in British AGRs. Adrian Simper, “Plutonium Management,” UK Nuclear Decommissioning Authority, February 2014, p. 10, <www.cnec.group.cam.ac.uk/presentations/NDA13Feb2014.pdf>.
54 Kessler erroneously assumes that the plutonium in the Nagasaki weapon was 0.98 of critical. 13 × (0.98/0.6) = 21.
55 Jones, “Reactor-Grade Plutonium and Nuclear Weapons,” pp. 82–83.
56 This method of securing US nuclear weapons is confirmed by the narrative summaries of several accidents. For example, on April 11, 1950, a B-29 carrying a nuclear weapon crashed and burned in New Mexico. The summary states, “Both the weapon and the capsule of the nuclear material were on board the aircraft but the capsule was not inserted for safety reasons.” On July 27, 1956, a B-47 crashed into a nuclear-weapon storage igloo. “No capsules of nuclear material were in the weapons or present in the building.” See “Narrative Summaries of Accidents Involving U.S. Nuclear Weapons, 1950–1980,” US Department of Defense, <www.hsdl.org/?view&did=26994>.
57 “Musharraf Rules out Accidental N-War with India,” Times of India, January 10, 2003, <https://timesofindia.indiatimes.com/world/pakistan/Musharraf-rules-out-accidental-N-war-with-India/articleshow/33957533.cms>.
58 “Restricted Data Declassification Decisions 1946 to the Present,” p. 76. In early weapons, the nuclear material was inserted manually; in later ones, mechanically.
59 Mark, “Explosive Properties of Reactor-Grade Plutonium,” p. 123.
60 At 1 meter away from a 5.9 kilogram plutonium core with a spontaneous neutron fission output of 432 n/g-s, the neutron dose would only be 2.5 mrem/hour. Even at this close distance, it would take over two thousand hours (about one year of standard forty-hour work weeks) to accumulate the 5 rem that is the US standard for annual worker exposure. “DOE Standard, Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities,” DOE-STD-1128-98, June 1998, Reaffirmation with Errata, May 2003, US Department of Energy, pp. 6–14, <www.hsdl.org/?view&did=441446>.
61 “Additional Information Concerning Underground Nuclear Test of Reactor-Grade Plutonium,” US Department of Energy, 1994, <www.osti.gov/opennet/forms.jsp?formurl=document/press/pc29.html>.
62 10 CFR 20.1003, <www.nrc.gov/reading-rm/doc-collections/cfr/part020/part020-1003.html>.
63 E.D. Clayton, “Anomalies of Nuclear Criticality, Revision 6,” PNNL-19176, Pacific Northwest Laboratory, Richland, WA, February 2010, pp. 108–12, <https://ncsp.llnl.gov/docs/PNNL-19176.pdf>.
64 Weapon-grade plutonium 95.2 percent Pu-239, 4.5 percent Pu-240, 0.3 percent Pu-241, reactor-grade plutonium 76.3 percent Pu-239, 20.2 percent Pu-240, 3.1 percent Pu-241, and 0.4 percent Pu-242. H.C. Paxton, “Los Alamos Critical Mass Data,” Los Alamos Scientific Laboratory, LA-3067-MS, revised December 1975, p. 40, <https://ncsp.llnl.gov/LA10860/technical/REF_020.PDF>.
65 Christer Larsson, “The History of a Swedish Atomic Bomb 1945–1972,” Ny Teknik, No. 17 (1985), pp. 55–83, translation from US Foreign Broadcast Information Service.
66 The reactor had a thermal power output of 457 MW and operated with a 45 percent capacity factor. The fuel burnup was 6,561 MWD/Te. At this burnup, the fuel would contain about 3.6 kilograms of plutonium per metric ton. For the fuel burnup at KANUPP see Muhammad Salim, Iqbal Ahmed, and Parvez Butt, “Experience in the Manufacture and Performance of CANDU Fuel for KANUPP,” pp. 1–48, <www.iaea.org/inis/collection/NCLCollectionStore/_Public/30/000/30000477.pdf>.
67 A year’s supply of fuel would have contained about 11.5 metric tons of uranium. Assuming a fuel burnup of 1,300 MWD/Te, 5.9 percent Pu-240, the fuel would contain only about 1.1 kilograms of plutonium per metric ton.
68 Leonard S. Spector with Jacqueline R. Smith, Nuclear Ambitions, The Spread of Nuclear Weapons, 1989–1990 (Washington, DC: Carnegie Endowment for International Peace, 1990), p. 90.
69 David Albright, Peddling Peril: How the Secret Nuclear Trade Arms America’s Enemies (New York: Free Press, 2010), pp. 18–19.
70 “Nuclear Power in India,” World Nuclear Association, updated February 2019, table “India’s operating nuclear power reactors,” <www.world-nuclear.org/information-library/country-profiles/countries-g-n/india.aspx>.
71 To generate plutonium that is 6 percent Pu-240, the reactors would produce 0.8 kilograms of plutonium per 1,000 MWDs of operation.
72 Assuming the last two years of Dhruva production have not yet been fully processed.
73 Zia Mian, A. H. Nayyar, R. Rajaraman, and M. V. Ramana, “Fissile Materials in South Asia and the Implications of the U.S.–India Nuclear Deal,” Science and Global Security, Vol. 14 (2006), p. 123, <www.princeton.edu/sgs/publications/articles/Fissile-Materials-South_Asia-SGS-2006.pdf>.
74 Hans M. Kristensen and Robert S. Norris, “Indian Nuclear Forces, 2017,” Bulletin of the Atomic Scientists, Vol. 73, No. 4, 2017, <www.tandfonline.com/doi/pdf/10.1080/00963402.2017.1337998?needAccess=true>.
75 Jones, “Reactor-Grade Plutonium and Nuclear Weapons,” p. 118.
76 India has confirmed Dhruva’s poor performance. See “Operation of Dhruva Reactor at Rated Power of 100 Mw on Sustained Basis,” BARC Newsletter, March–April 2016, <www.barc.gov.in/publications/nl/2016/2016030401.pdf>.
77 Robert Gillette, “Low-Grade Fuel Used in A-Bomb Test,” Los Angeles Times, September 14, 1977, p. B1.
78 Bruno Pellaud, “Proliferation Aspects of Plutonium Recycling,” C. R. Physique, Vol. 3 (2002), p. 1,070, <https://ac.els-cdn.com/S1631070502013646/1-s2.0-S1631070502013646-main.pdf?_tid=0977685b-a61b-40a7-8a9e-f5e06b4d61bc&acdnat=1539621205_ef6fcb7665c8f8cbada94a0373616ee9>.
79 Gregory S. Jones, “What Was the Pu-240 Content of the Plutonium Used in the U.S. 1962 Nuclear Test of Reactor-Grade Plutonium?” May 6, 2013, <http://nuclearpolicy101.org/wp-content/uploads/2013/05/Reactor-grade-plutonium.pdf>.
80 “Depleted Uranium Irradiations in the Single-Pass Reactors to Produce High Pu-240 Plutonium,” Monthly Report, September 1968, DUN-4452, Douglas United Nuclear, Richland WA, October 16, 1968, p. I-1, <www.osti.gov/servlets/purl/69099>.
81 W.A. Blanton, “I & E Depleted Uranium Fuel Element Ruptures Experienced under PT-IP-132-AC,” HW-58281, General Electric, Richland, WA, December 1, 1958, <www.osti.gov/servlets/purl/10158744>; R.E. Hall, “Irradiation Summary Report PT-IP-231-A, Irradiation of Depleted Uranium to High Exposure,” HW-62232, October 7, 1959, <www.osti.gov/servlets/purl/10154970>.
82 “Monthly Record Report, Irradiation Processing Department, January, 1959,” HW-59041, General Electric, Richland, WA, February 20, 1959, p. B-27, <www.osti.gov/servlets/purl/10164437>; “Depleted Uranium Irradiations in the Single-Pass Reactors to Produce High Pu-240 Plutonium,” p. I-7.
83 See, e.g., H.K. Hardy, J.F.W. Bishop, D.O. Pickman, and V.W. Eldred, “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. This article indicates that channel average burnups of over 3,000 MWD/Te had been achieved. The central fuel elements in such channels would have a burnup of 4,500 MWD/Te, which would produce plutonium with a Pu-240 content of 23 percent. Though the article was published at the beginning of 1963, the data had to have been from the latter part of 1962.
84 Geoffrey Lean, “DIY Atom Bomb Link to Sellafield,” The Observer, June 6, 1993, p. 3.
85 “Plutonium,” World Nuclear Association, note d.
86 Alex DeVolpi, “A Coverup of Nuclear Test Information?” Physics and Society Newsletter, Vol. 25, No. 4 (1996), <www.aps.org/units/fps/newsletters/1996/october/aoct96.html>. DeVolpi has repeated this claim more recently: Alexander DeVolpi, “Demilitarizing Weapon-Grade Plutonium: Part II,” APS Physics Newletter, July 2015, <www.aps.org/units/fps/newsletters/201507/plutonium2.cfm>.
87 Jones, “Reactor-Grade Plutonium and Nuclear Weapons,” pp. 137–40.
88 Robert Gillette, “Impure Plutonium Used in ’62 A-Test,” Los Angeles Times, September 16, 1977, p. B11.
89 Albert Wohlstetter, Thomas A. Brown, Gregory Jones, David C. McGarvey, Henry Rowen, Vince Taylor, and Roberta Wohlstetter, Swords from Plowshares (Chicago and London: University of Chicago Press, 1979), pp. 153–54.