DISPOSITION OF EXCESS WEAPON PLUTONIUM AND URANIUM September 8, 1997 4th Pugwash Workshop on The Future of the Nuclear Weapons Complexes of the U.S. and Russia Moscow and Snezhinsk, 9-13 September 1997 DISPOSITION OF EXCESS WEAPON PLUTONIUM AND URANIUM Richard L. Garwin ABSTRACT. Numerous papers have laid the groundwork for the disposition of excess weapon plutonium and uranium, most recently the Final Report of U.S.-Russian Independent Scientific Commission on Disposition of Excess Weapons Plutonium" (June 1, 1997). The present paper summarizes those agreed recommendations, adds some further remarks by the author, and comments on certain aspects of the U.S. program. Neither the spending nor the organizational activity is yet appropriate to the clear and present danger posed by excess material suitable for fabricating tens of thousands of nuclear warheads, which poses a danger of proliferation or rearmament until it is irrevocably separated from the military sector and ultimately disposed of so as to meet the Spent Fuel Standard so that it poses little additional risk to that presented by the much larger amount of plutonium present in the spent fuel from civil power plants worldwide. INTRODUCTION. Numerous reports and analysis have evaluated the clear and present danger posed by the excess plutonium and high enriched uranium (HEU) from the tens of thousands of nuclear weapons now surplus to the START I, START II, and the hoped-for START III agreements between the U.S. and the former Soviet Union and the U.S. and Russia. Among them are three Committee reports of which I was an author(1) Thus far in the United States many thousands of weapons are held in reserve, since the START agreements limit only deployed strategic weapons, but some 1500 weapons per year have been dismantled over the last six years or so, so that the components from many thousands of weapons exist in storage. The situation in Russia is believed to be similar, although Russia has made no formal declaration in this matter. In the United States the HEU parts are shipped to Oak Ridge, where they are stored until they are eventually to be blended down with natural or low enriched uranium (LEU) to provide fuel for civil reactors. The plutonium is contained in sealed "pits", roughly spherical hollow metal assemblies, each with a "fill tube" projecting from it, that is used to inject a mixture of deuterium and tritium gas just before the nuclear explosion. The pits are placed in durable storage containers and stored, many of them in "igloos" in a protected area of the Pantex plant at Amarillo, Texas. As is familiar to all readers, the United States has initiated a program to dispose of this excess weapons usable material. The former Secretary of Energy has declared total U.S. production of plutonium over the years at just under 100 tons, and the disposition program is committed to burn part of the excess weapon plutonium as mixed-oxide fuel (MOX) in commercial power reactors, while disposing of another part of the excess with a protective barrier of highly radioactive fission products, in the form of vitrified glass logs in stainless steel containers that will be placed in the Yucca Mountain repository now being prepared to receive also spent commercial reactor fuel. The paper summarizes the existing status in the United States and some problems. CURRENT SITUATION. The June 1 Final Report of the U.S.-Russian Independent Scientific Commission(2) makes unanimous recommendations in each of the categories: A. Overall Approach A.1 The U.S. and Russian governments, with support and cooperation from the international community, should take additional steps - beyond those already underway - to more rapidly reduce the security risks posed by excess weapons plutonium. A.2 Two approaches to reducing the weapons-usability of the excess plutonium to the spent-fuel standard - using the plutonium in mixed oxide (MOX) fuel for burning once-through in currently operating nuclear power reactors, and vitrifying the plutonium together with fission products in glass logs of the type planned for use in immobilizing high-level radioactive wastes from the defense- production complex - should both be brought to the point of operability at large-scale as rapidly as practicable in both countries. A.3 The highest standards of materials protection, control, and accounting - as appropriate to the threat of theft or diversion - should be applied to excess weapons plutonium at all storage, processing, and transport steps until it reaches the spent-fuel standard. The same is true of HEU until it has been blended down to enrichment levels too low for use in nuclear explosives. A.4 Increased transparency about the inventories of nuclear warheads and nuclear-explosive materials possessed by the United States and Russia, and about the steps being taken to reduce these inventories, should be pursued. A.5 The U.S. and Russian programs of warhead dismantlement and management and disposition of the associated nuclear-explosive materials should continue to proceed in parallel, seeking to complete comparable steps in this process on comparable time scales, and to reach equivalent remaining quantities of plutonium and HEU in the two military stockpiles. A.6 Increased funding should be provided on an urgent basis for analysis, development, testing, licensing, and deployment of the systems for management and disposition of weapons plutonium and HEU as described here. B. Storage, Protection, Control, and Accounting B.1 The U.S. and Russian governments should continue to cooperate in providing secure storage for fissile materials removed from nuclear weapons, and in improving security and accounting for all separated plutonium and HEU. B.2 The United States and Russia should move quickly to implement and expand on the reciprocal information exchanges and mutual inspections related to nuclear stockpiles that have been agreed to in principle, to help ensure the transparency and irreversibility of nuclear arms reductions. B.3 As the P-8 leaders agreed at the Moscow Nuclear Safety and Security Summit in April of 1996, excess plutonium and HEU should be placed under international safeguards as quickly as practicable. B.4 Russia, like the United States, should begin declaring specific quantities of nuclear material to be excess to its military needs. B.5 Both countries should seek to make additional tens of tons of material eligible for International Atomic Energy Agency (IAEA) safeguards during 1997. C. Disposition of Excess Plutonium C.1 The United States and Russia should move promptly to select, authorize, fund, and bring to the point of operability at the necessary scale the specific variants of both the MOX/current-reactor approach and the vitrification-with-wastes approach that will be used for disposition of excess weapons plutonium to the spent-fuel standard in each country. C.2 The two governments should establish appropriate managerial structures - one in each country, as well as an international framework for managing joint activities - to be responsible to the Presidents for carrying out this work to specified endpoints on a specified timetable. C.3 The United States and Russia should expedite and expand their technical cooperation focused on developing, testing, and demonstrating rapidly implementable and cost-effective means for converting pits to oxide suitable for MOX-fuel fabrication, and for processing other plutonium forms to prepare them for disposition. C.4 The United States and Russia, along with other countries with relevant experience, should expand their technical cooperation related to analyzing, testing, licensing, and demonstrating the fabrication of MOX fuel made from weapons plutonium and the use of this fuel in currently operating reactors. C.5 The United States, Russia, and the international community should begin now to address the largest obstacle to progress on plutonium disposition beyond interim storage, which is financing and constructing adequate capacity in the two countries for processing plutonium pits into plutonium oxide and for fabricating plutonium and uranium oxides into MOX fuel. C.6 In order to facilitate rapid initiation of plutonium disposition in MOX fuel, contracts should be sought with existing European MOX fabrication plants to produce initial batches of weapon-plutonium MOX for U.S. and Russian reactors, while MOX fabrication facilities in the United States and Russia are being prepared. C.7 Because of the urgency of proceeding with disposition to the spent-fuel standard, both the United States and Russia should begin their programs for this purpose using currently operating reactors. C.8 Work should be continued to prepare for the possibility of weapon-plutonium/MOX use beyond the U.S. and Russian reactors now planned for the first phase of the reactor-disposition approach and/or beyond the partial MOX core loadings likely to be used initially in these reactors. C.9 The United States and Russia, along with other countries with relevant experience, should expand their technical cooperation related to analyzing, testing, licensing, and demonstrating vitrification of plutonium with high-level radioactive wastes. C.10 The nuclear-regulatory agencies in both countries should be directed - and funded - to develop the procedures to review and license promptly the MOX fuel fabrication plants, reactors using MOX fuels, and plutonium-with-waste vitrification plants needed to implement weapons-plutonium disposition. C.11 The United States and Russia should move as quickly as practicable to end additional production of weapons plutonium, including providing the necessary financing to complete their cooperative project to convert the cores of the plutonium production reactors at Seversk (Tomsk-7) and Zeleznogorsk (Krasnoyarsk-26). C.12 The United States and Russia should begin discussions with the goal of reaching a formal agreement governing plutonium disposition. Of course, I agree with this Final report, which was the result of considerable joint effort among the ten members and their Executive Secretaries D.F. Tsourikov and M.G. Bunn. In addition, I had occasion on July 24, 1997, to address the Secretary of Energy and the Department of Energy(3) and used my three minutes available as follows: Thank you, Mr. Secretary. The Enrico Fermi Award celebrates past achievements, but we need also to move ahead with the opportunities of the post-Cold-War world. Here are three: First, in January the U.S. Government announced its decision to dispose of its excess bomb plutonium from stocks and dismantled nuclear weapons BOTH by incorporating a portion of it with the radioactive wastes being converted into durable glass for underground storage AND by using a portion of it for fuel in U.S. power reactors. As one of the five U.S. members of an Independent Scientific Commission created by Presidents Clinton and Yeltsin, I urge that we move without delay to carry out this decision and thus reduce the serious hazard that this material, particularly Russian material, will end up in nuclear weapons in the hands of terrorists or of nations thirsting for nuclear weaponry. Second, in carrying out its obligation to maintain U.S. nuclear weapons reliable, safe, and secure, the Department of Energy needs every few years or every decade to refresh the supply of tritium in each nuclear weapon. Because active-duty U.S. nuclear weapons have been reduced in number over this decade and the next much more rapidly than the loss of tritium by radioactive decay (50% every 12 years), there has been and until the year 2010 or so there will be more than enough tritium available for this purpose without the manufacture of new tritium. DOE has programs to develop a powerful particle accelerator to recreate tritium from its helium ashes, and one to produce tritium in power reactors. Billions of dollars would be saved by choosing the reactor route, and that should be perfected and held in reserve. But the opportunity is really the purchase of tritium from Russia, which I understand is ready to sell it at a small fraction of the cost to the U.S. of even reactor production. No impairment of U.S. security can result, if tritium is acquired 5 years before it is needed; if the supply is cut off, there is thus time to begin domestic production. And if Russian and U.S. nuclear weapons are reduced from the 10,000 we plan to hold under current agreements, we will save not only major capital expenditure but also the cost of tritium purchase. Third, the U.S. is purchasing 500 tons of Russian bomb uranium ("high enriched uranium"--HEU) over 20 years, blended down as low-enriched power reactor fuel useless for nuclear weapons; deliveries began about two years ago. The HEU awaiting delivery is directly usable to make some 20,000 nuclear weapons. We could eliminate this hazard of nuclear proliferation to terrorists or weapon-thirsty states by paying Russia to blend all this HEU now to 20% U-235 (also useless for nuclear weapons), and to receive a credit for this payment when we take delivery of the reactor fuel further blended down to 4.4% U-235. I know that many of my colleagues in the scientific, technical, and foreign policy communities are ready to help realize these opportunities. The full text of the Final Report of the U.S.-Russian Independent Commission is available at this meeting, so I now comment on the situation in the United States. There is no entrenched bureaucracy that is going to benefit by urgent activity on this disposition program, no matter how important it is to the security of the United States or to the world. Thus the Secretary of Energy and the President and the Vice President must take the lead in creating such a bureaucracy and in giving it a kick start. In general there are problems associated with both options, as envisioned by the CISAC panel in its report, and that is the reason for advocating that both approaches go ahead rapidly in both countries. THE MOX ROUTE. The Department of Energy has a substantial component in its leadership that is no great supporter of nuclear power in any form, and certainly opposes reprocessing of commercial spent fuel. I am, myself, totally opposed to reprocessing of spent lightwater reaction (LWR) fuel in the United States or the reprocessing of U.S. LWR fuel anywhere in the world, and the reasons are those of the famous Ford-MITRE study.(4) It is just not economical, and so far as I can see from my review of the situation in recent years, including a visit to the well-run COGEMA plant at La Hague, the processing adds additional potential problems for radiation leakage, without reducing significantly the problems of storage and of geologic disposal. Some equate the burning of excess weapon plutonium in commercial reactors with "closing the cycle" for commercial reactor fuel, which RESULTS in the burning of MOX in reactors. But the two are very different: In the one case one is disposing of a hazard, while in the other one is creating a hazard and then partially disposing of it. Perhaps spurred by outside critics, DOE seems inclined to require a further Record of Decision (ROD) before proceeding, whereas it is the view of the five U.S. members of the Commission that no such additional ROD is required and that the decision has already been made and all that remains to be done is to implement it and to choose the particular contractors and reactors which will handle the MOX. Of course, as indicated by the recommendations cited above, the U.S. still needs to fabricate weapon plutonium into MOX, and a suitable plant for this processing (including the removal of gallium) needs to be built. So that is the problem on the MOX side. THE VITRIFICATION ROUTE. The 1994 and 1995 CISAC reports envisaged largely the feeding of plutonium oxide into the stream of fission product entering a melter at the Savannah River Plant (SRP) in the United States, and loading about 1% Pu by weight into the vitrified glass in this way. The normal glass appears to hold at least 7%, so there should be no problem with this 1%. The SRP has begun now the vitrification of high-level fission product waste leftover from the separation of that very same weapon plutonium, and they use now a very large melter instead of the bench-size melters in use at COGEMA. I believe that this was a strategic error, and I would hold this opinion whether or not one needed to dispose of excess weapon plutonium. The development cost for such a large melter is substantially greater than the cost for small melters, and one has far less flexibility in improving, changing, and the like. For the disposition of weapon plutonium, the large melter poses a particular problem, since the tens of kilograms of plutonium that would be present in the melter at any one time must be guaranteed not to segregate and cause criticality problems. So SRP has proposed the "can in canister" approach, in which plutonium is vitrified without fission products and placed in cans that occupy 10-30% of the volume of the ultimate canister, supported on a structure inside the canister. The vitrified fission products are then poured around the structure. Of course, if the same amount of plutonium (say 20 kg per canister) is to be loaded into cans that fill 10% of the volume, the plutonium concentration in the cans must be 10%, so a different glass must be used. In fact, some argue that ceramic rather than glass is a better solution for the material inside the can, and the Department of Energy is reputed to be ready to announce a decision in October 1997 to use such a ceramic instead of glass. But the plutonium in the ceramic or in the glass is not intimately mixed with fission products, and so there is a substantial portion of the cycle where the plutonium is not protected against approach or theft, and even after it is disposed, it may be possible by the use of explosives to separate these cans, although that would be a rather messy procedure. I criticize DOE and Savannah River Plant in this because we have lost years on this program because of the initial decision to use a large melter, although there is no reason to believe that a ceramic approach (much like that used in providing MOX fuel for an LWR or a breeder reactor) would be inadequate, because it is much like the process involved in producing MOX fuel for a LWR or for a fast reactor. Nevertheless, a production line needs to be set up to handle all of the plutonium and to fabricate such glass or ceramic, and this line will need to handle all of the plutonium and 10% or 30% of the mass of the canister fill. THE DUAL-TRACK APPROACH IN RUSSIA In many discussions of the Independent Scientific Commission, CISAC, and other groups, Russian representatives have expressed a strong and principled position in favor of burning excess W-Pu as MOX (in this way releasing some of the energy stored in the plutonium); they have scorned the idea that excess W-Pu is a "waste" because it costs more to burn as fuel in reactors than the cost of fresh enriched uranium fuel. Nevertheless, the Spent Fuel Standard has been adopted by the Russian side, and vitrification experiments are indeed going forward, so that both the U.S. and Russia will benefit from the research on both sides. ---------------- 1 Panofsky, W.K.H., Chair, "Management and Disposition of Excess Weapons Plutonium," Report of the National Academy of Sciences, Committee on International Security and Arms Control, January 1994; 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, July 1995; and Holdren, J.P. and Velikhov, E.P. (Co-Chairs), "Final Report of U.S.-Russian Independent Scientific Commission on Disposition of Excess Weapons Plutonium" by J.P. Holdren (Co-Chair), J. Ahearne, R.L. Garwin, W.K.H. Panofsky, J.J. Taylor, and E.P. Velikhov (Co-Chair), A.A. Makarov, F.M. Mitenkov, N.N. Ponomarev-Stepnoi, F.G. Reshetnikov, 1 June 1997. The first two are available on the Web at http://www.nap.edu, and the third will be available at http://www.fas.org/rlg and copies are available at this Pugwash Workshop. 2 E.P. Velikhov (Co-Chair); A.A. Makarov; F.M. Mitenkov; N.N. Ponomarev-Stepnoi; F.G. Reshetnikov. and J.P. Holdren (Co-Chair); J. Ahearne; R.L. Garwin; W.K.H. Panofsky; J.J. Taylor. 3 On receipt of the Enrico Fermi Award. 4 Keeny, S.M., Chairman, NUCLEAR POWER ISSUES AND CHOICES, sponsored by the Ford Foundation-MITRE Corporation, Ballinger Publishing Co, March 1977. RLG:jah:W251DEWP:090897DEWP