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Options and Choices in the Disposition of Excess Weapon Plutonium

Published online by Cambridge University Press:  15 February 2011

R. L. Garwin
R. L. Garwin*
Affiliation:
IBM Fellow Emeritus, IBM, T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598, RLG2, at, watson.ibm.com, and Member of the National Academy of Sciences study on disposition of excess weapon plutonium
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Abstract

More than 50 tons of weapon-related plutonium (WPu) is expected to become excess andavailable for disposition by the year 2003 in Russia and a similar amount in the United States.Per two reports from the Committee on International Security and Arms Control of the NationalAcademy of Sciences (1994 1 and 1995 2), the hazard of theft and incorporation into nuclearweapons impels us to guard this Pu carefully and as soon as possible to transform it into a formless accessible for use in nuclear weapons. To this end, CISAC adopted the “Spent FuelStandard” for the disposed WPu, which, if met, renders the WPu no greater hazard per kg thanthe much larger amount of reactor Pu in the form of spent fuel, since CISAC finds that separatedRPu can be used for nuclear weapons with little additional difficulty beyond that posed byseparated WPu. Many disposition routes can be eliminated on the basis of cost or other metric.The two principal survivors (of about equal cost and difficulty for the United States) are thepartial burning of WPu as MOX and the direct vitrification of WPu (as oxide) with high-level‘defense wastes’. Both these approaches should be pursued urgently, with experiments toqualify the processes, until one is selected on the basis of hard evidence. Either approach wouldcost about $1 B, within a factor two, to dispose of 50 tons of excess WPu. The CISAC analysiswill be presented, with comments on utility of RPu in weapons, on the DOE PlutoniumDisposition Study, and on ‘explosive criticality’ in the repository.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 412: Symposium V – Scientific Basis for Nuclear Waste Management XIX , 1995 , 3
Copyright
Copyright © Materials Research Society 1996

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References

1. Panofsky, W.K.H. (Study Chair), Management and Disposition of Excess Weapons Plutonium, Report of the National Academy of Sciences, Committee on International Security and Arms Control, (National Academy Press, Washington, D.C. 1994).Google Scholar
2. Holdren, J.P. (Chair), Management and Disposition of Excess Weapons Plutonium: Reactor-Related Options, Report of the National Academy of Sciences, Committee on International Security and Arms Control, Panel on Reactor-Related Options for Disposition of Excess Weapons Plutonium, (National Academy Press, Washington, D.C. 1995).Google Scholar
3. Not just plutonium removed from excess weapons, but also weapon-grade Pu that has never been in weapons, is in the form of scrap or dust, etc.Google Scholar
4. But according to the U.S. 1994 Nuclear Posture Review, it is planned to retain “reserve” warheads so that the total U.S. stock in the year 2003 would be about 8000. Personally, it seems to me that the benefit to U.S. security of limiting the total number of Russian nuclear warheads to 3500 (including any reserves), needs to be weighed against the value of U.S. reserve weapons.Google Scholar
5. One gram of high-explosive yields about 4.2 kJ, so one ton is 4.2 GJ, and one KT is 4.2 TJ. The nuclear weapons used against Hiroshima and Nagasaki were on the order of 20 KT, so almost 100 TJ.Google Scholar
6. The U.S. has long stated that about half the energy of Soviet thermonuclear weapons comes from such fission.Google Scholar
7. The complete fission of 1 kg of U235 or Pu239 contributes about 17 KT of energy release. In that case, 4 moles of fission produce about 10 moles (10 grams) of neutrons.Google Scholar
8. I.e., a mixture of deuterium and tritium.Google Scholar
9. For α-phase, density 19.6 g/cm3. See Mark, J.C., “Explosive Properties of Reactor-Grade Plutonium,” Science & Global Security, 1993, Vol.4, pp. 111–128.Google Scholar
10. Because the neutron spectrum in a power reactor is not a pure “thermal” spectrum, some of the higher energy neutrons do cause fission in Pu240, but only about 0.3% of the Pu240 destroyed in such a reactor disappears by fission, compared with 99.7% by radiative capture to form Pu241.Google Scholar
11. Why should it have been? After forming Pu239 from neutron capture on U238, continued operation of a reactor then burns up that Pu239 by fission and by capture of additional neutrons to form Pu240. Furthermore, WPu provides a lesser radiation dose to the nuclear weapon workers and the military in handling and storage than does RPu.Google Scholar
12. Reference I addresses this question specifically (pp. 32–33), noting that means exist to handle the greater heat evolution and the substantially larger background neutron generation rate. The National Academy Panel, including several individuals long involved in the U.S. nuclear weapons program, concluded “In short, it would be quite possible for a potential proliferator to make a nuclear explosive from reactor-grade plutonium using a simple design that would be assured of having a yield in the range of one to a few kilotons, and more using an advanced design.” This conclusion was based on the arguments given in the text, but was supported by a classified weapon design study done specifically for CISAC.Google Scholar
13. And from the tens of tons of weapon-related WPu in plants and in process.Google Scholar
14. Schwartz, S.I., Editor, “Four Trillion Dollars and Counting” Bulletin of the Atomic Scientists, November/December 1995 (pp. 32–52).Google Scholar
15. That is, a divergent chain reaction caused by agglomeration of kilograms of WPu.Google Scholar
16. Mixed-oxide ceramic fuel-- that is, typically 5% RPu oxide in depleted uranium oxide.Google Scholar
17. If new approaches to reprocessing and fuel fabrication reduce these costs very substantially, these judgments would change accordingly.Google Scholar
18. Jaumotte, A. and Michel, A., presented at the 8th Amaldi Conference, Piacenza, Italy, October 1995.Google Scholar
19. Chan, P., Pitre, J., and Dastur, A., presented at the International Conference on Evaluation of Emerging Nuclear Fuel Cycle Systems, Versailles, France, September 1995.Google Scholar
20. “Protection and Management of Plutonium,” American Nuclear Society, 1995 (86 pp.).Google Scholar
21. U.S. Department of Energy Plutonium Disposition Study (PDS), Technical Review Committee Report, Vol. II (July 2, 1993).Google Scholar
22. However, insufficient effort is being supported on actual experimental work toward implementing vitrification of WPu with HLW. Certainly there are other possible approaches, including “immobilization” in glass or ceramic, with HLW glass in the same can, or with Cs137-glass in the same can. But no approach will be viable without both development and technical challenge, and the lack of commitment to real development of the vitrification option denies the nation one of the two reasonably near-term options for the disposition of WPu. A suitable approach is to pursue both the MOX option in LWRs and vitrification with HLW with the commitment to realize both, and then with any additional funds to explore other immobilization options that might provide solutions on the same timescale, dropping them as soon as they can be seen to be non-competitive.Google Scholar
23. Bowman, C.D. and Venneri, F., LA-UR-94-4022A, Los Alamos National Laboratory document (December 1994).Google Scholar
24. Venneri, F., personal communication to the author (October 26, 1995).Google Scholar
25. Sanchez, R., Myers, W., Hayes, D., Kimpland, R., Jaegers, P., Paternoster, R., Rojas, S., Anderson, R., and Stratton, W., LA-UR-95-2130, Los Alamos National Laboratory document (August 15, 1995).Google Scholar
26. Which after 50,000 years would contain about 3% U235 formed from the decay of Pu239 Google Scholar
27. Taylor, E.C., Ramspott, L.D., and Sprecher, W.M., “Demonstration of Safety for Geologic Disposal” in Scientific Basis for Nuclear Waste Management XVII. edited by Barkatt, A. and Van Konynenburg, R.A. (Materials Research Society, Pittsburgh, PA) pp. 199–207.Google Scholar