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Russia: Introduction to Plutonium Disposition Senior Research Associate NIS Nonproliferation Project Center for Nonproliferation Studies 21 November 1997 Due to the ongoing dismantlement of warheads removed from missiles under the START I agreement and other disarmament efforts, Russia and the US have each accumulated about 50 metric tons of weapons plutonium considered surplus to military needs.[1,2] The two countries are considering ways to render the surpluses difficult to steal or to reuse in nuclear weapons. The effort, which will take decades to complete, would mark the first time that the long-term fate of plutonium stockpiles will have been addressed by either country. Arms control agreements to date have focused on disabling delivery systems, but have not addressed the security and arms control problems associated with the fissile materials contained in nuclear weapons. Hundreds of tons of highly enriched uranium (HEU) are also considered to be excess to military needs. 500 metric tons of Russian HEU is being isotopically blended down to a non-weapons-usable low enriched uranium (LEU) form for sale to the United States. (Click here for an overview of the US-Russia HEU deal.) Plutonium stocks can not be blended in a similar fashion, because virtually every isotopic mix of plutonium is weapons-usable, with the exception of mixtures containing substantial quantities of Pu-238. Moreover, long term storage of plutonium in weapons-ready form is considered insufficiently secure, because of the uncertain long-term stability of the nations controlling the material--the changing political and military climate in the former Soviet Union being a prime example of such instability. Instead, to secure the material against theft or rapid reuse in weapons, intrinsic physical, chemical, and radiological barriers to recovery of the plutonium must be put in place. THE RISKS ASSOCIATED WITH SURPLUS PLUTONIUM AND THE BENEFITS OF DISPOSITION The removal of plutonium from warheads brings about several security risks. The first is that both Russia and the United States can rapidly re-arm using plutonium removed from weapons, should either country choose to violate existing arms control agreements. This is particularly true for plutonium stored as metal "pits" (the hollowed-out spheres of plutonium that lie at the heart of a nuclear warhead) since no remanufacturing of the pit is necessary prior to its reintroduction into a warhead. Secondly, plutonium in weapons-ready form is an attractive target for terrorists and other sub-national groups interested in acquiring nuclear weapons. The possibility of theft of HEU and plutonium is particularly acute in Russia, where the previously tightly integrated and highly secret nuclear complex is now in a state of disarray and great financial uncertainty. Finally, weapons-ready surplus plutonium in the major nuclear weapons states indicates to non-nuclear states and lesser nuclear powers that neither country is willing to abandon the possibility of rapid rearmament. Thus the existence of surplus military plutonium endangers both arms reduction and nonproliferation regimes. A bilateral US-Russian disposition program would provide four arms control and nonproliferation benefits. First, completion of such a program would make surplus military plutonium much harder for terrorists or sub-national groups to steal or manufacture into weapons. Second, it would increase the difficulty of reuse of the material in weapons by either country. Third, it would provide a substantial nonproliferation benefit by sending a strong signal to the rest of the world that the major nuclear powers are on a path to irreversible reductions in their huge nuclear arsenals. Finally, it would provide incentive for further US and Russian nuclear arms reductions, by demonstrating practical methods for reducing the array of threats associated with plutonium once it is removed from nuclear weapons. QUANTITIES AND PHYSICAL FORM OF SURPLUS STOCKS Russia has declared 50 metric tons of plutonium to be surplus to its military needs and announced its intention to place this material under International Atomic Energy Agency (IAEA) safeguards. However, Russia has not issued any detailed information about the size or physical composition of its stockpile. The best publicly available estimate of the total Russian stockpile of military plutonium is 106-156 metric tons,[3] compared to about 100 metric tons (85 tons weapons-grade) in the United States[4]. Informal statements by Minatom officials indicate that about 50 metric tons of its military stockpile will be declared surplus,[2] and possibly as much as 100 metric tons.[5] The Russian military surplus plutonium is isotopically pure, or weapons-grade, material. This means it contains more than 93 percent of the fissile isotope Pu-239, and less than 7 percent of other plutonium isotopes. Such plutonium is best suited for weapons production, although reactor-grade plutonium, containing larger amounts of higher isotopes, can also be used in weapons[6]. In addition to the nominal 50 metric ton military surplus of weapons-grade plutonium, Russia has approximately 30 metric tons of weapons-usable reactor-grade plutonium in storage at the Mayak Chemical Combine near Chelyabinsk. While this stockpile has received far less attention in news reports and in US and Russian negotiations on plutonium disposition, the security risks associated with it are similar to those of the military surplus. The Russian disposition program may nonetheless begin with this stockpile, due to technical and economic problems associated with the age of the reactor-grade surplus material.[5] As in the United States, it is likely that much of the Russian military surplus will be in the form of metal pits. Smaller but still significant amounts of surplus material will probably be in the form of chemically pure plutonium oxide powder, impure oxides, fresh reactor fuel, salts, and other forms. The physical form of the material is closely related to its attractiveness as weapons material. One measure of attractiveness is the "conversion time," defined as the time it takes to convert plutonium from a given form to a finished weapon component. For a plutonium pit, which is already a finished component, the conversion time is zero. Estimates of conversion times for various forms of plutonium have been made by the IAEA. (These numbers assume an existing plutonium processing infrastructure.) As seen in the linked table, the least attractive form of plutonium by this measure is irradiated reactor fuel. This highly radioactive fuel must be reprocessed via expensive and hazardous chemical techniques in order to separate out the plutonium it contains. The expense and technical difficulty of reprocessing makes the plutonium in spent fuel significantly less of a security threat than separated plutonium. MILITARY VERSUS CIVIL STOCKS OF SPENT FUEL: THE SPENT FUEL STANDARD The leaders of the G7 and Russia agreed at the April 1996 Summit on Nuclear Safety and Security that plutonium surpluses should be transformed into "spent fuel or other forms equally unusable for nuclear weapons."[7] This level of protection against recovery and use is referred to as the "spent fuel standard". The logic of the spent fuel standard is described in a 1994 NAS report on plutonium disposition.[8] That report argues that because there are substantially greater, and increasing, amounts of plutonium in global stocks of spent fuel (750 metric tons) than in military stockpiles (260 metric tons)[9], there is little strategic advantage in making the military surplus stockpile more secure than the civil spent fuel stockpile. The study concluded that the modest advantage in making the military stocks more difficult to use in weapons than civil stocks would be undermined by the additional delays and costs introduced in the process of reaching the extra level of protection. This policy position had the result of effectively removing from consideration a class of technologies that would eliminate plutonium, such as accelerator-based or reactor-based transmutation. The spent fuel standard as described by the NAS is an interim standard. It reduces the problem of securing military plutonium to that of securing unseparated civil plutonium. However, the NAS study emphasized that "Further steps should be taken to reduce the proliferation risks of all of the world's plutonium stocks, military and civilian, separated and unseparated; the need for such steps exists already, and will increase with time."[8] PREFERRED DISPOSITION TECHNOLOGIES In both Russia and the United States, a wide variety of technologies have been considered for the purpose of plutonium disposition.[10] The US-Russian Independent Scientific Commission, a body organized at the behest of President Yeltsin, has identified two preferred methods using a variety of criteria, including the spent fuel standard, cost, and speed of startup and completion.[11] The first is to fabricate a mixed oxide (MOX) fuel composed of plutonium and uranium oxides for use in currently operating light water reactors. Figure 1 shows a schematic of this method.[12] The spent fuel resulting from reactor irradiation would be in the form of a massive, highly radioactive fuel assembly containing low concentrations of plutonium. The radioactivity in spent fuel comes from the byproducts of the fission process produced in the fuel during reactor irradiation. The second disposition method is immobilization of the plutonium at low concentrations (5 to 10 percent, compared to the 90 to 100 percent concentrations of plutonium in metallic and oxide forms) along with high level radioactive waste (HLW) in a large, heavy glass or ceramic waste form. Figures 2, 3 and 4 show possible immobilization methods as presented in the US DOE Technical Summary Report.[13] As with spent fuel, the main barrier to theft and recovery of plutonium from the immobilized waste is radiological. Most of the radiation is due to the Cs-137 component of the HLW, which emits penetrating gamma rays and has a half life of about 30 years. The direct immobilization methods shown in Figures 2 and 3 involve the homogeneous mixing of plutonium in glass or ceramic material along with high-level radioactive waste. In the "can-in-canister" method shown in Figure 4, plutonium is separately vitrified or ceramically immobilized in small cans at concentrations of five to ten percent. Next, several of these cans are placed in a large canister, which is filled with molten vitrified HLW that cools and entombs the cans within the canister. This method is being considered by both the United States and Russia,[14] because it is technically simple and quicker to implement than simultaneous immobilization of plutonium and HLW. Both reactor and immobilization methods would make military surplus plutonium about as difficult to recover as the plutonium contained in spent fuel from civil reactors. Both would make it significantly more difficult and expensive to recover the plutonium for weapons use, as is discussed in more detail below. Neither technology eliminates strategically significant quantities of plutonium: no plutonium is destroyed by the ceramic and glass immobilization processes, while light water reactors destroy from 20 to 60 percent of their inital plutonium load.[15] (Breeder reactors can operate in a net plutonium consumption mode, but to consume 90% of the nominal 50 metric ton military surplus would take a minimum of several decades and involve the expensive and time-consuming construction of reactors dedicated to the task.[16] As explained above, adherence to the spent fuel standard all but removes newly built breeder reactors from consideration for the disposition program.) The difficulties associated with breeder reactors notwithstanding, high-ranking Russian scientists and officials have expressed a strong preference for the use of plutonium as fuel in breeders, although use of light water reactors is also being considered. Immobilization methods currently rate a distant third in the ranking of disposition options among Russian scientists and Minatom officials, who believe immobilization "would result in irreparable loss of a valuable energy source." [2] Despite this belief, all disposition methods will very likely involve a substantial net cost, even when the recovery and sale of energy from plutonium fuel use is taken into account. In Russia, the disposition program is expected to be integrated into a larger program of plutonium use in civil reactors.[17] This approach is diametrically opposite that of the US government, which advocates plutonium use in reactors only as an expedient specifically targeting military plutonium.[18] The impact of disposition on the civil nuclear fuel cycle is discussed in a separate section. Companies from the European, Canadian, and Japanese nuclear industries have expressed interest in aiding the Russian plutonium disposition program, with the expectation of government subsidy Russian officials have proposed the use of one or more newly built BN-800 fast reactors (operated in non-breeding mode) or of high temperature gas reactors.[2] However, because of the current financial crisis in the civil and military nuclear complex, it is unlikely that these reactors will be built in Russia in time to affect the disposition campaign. ( Click here for more information on the status of the breeder reactor program in Russia.) Use of existing Russian VVER-1000 LWRs has also been proposed.[19] This option will be complicated by the absence of experience in Russia with MOX fuel fabrication for light water reactors, and by the sub-par safety standards of the VVERs (although the newer VVER-1000 series is considered safer than most other Russian reactors.) Citing these concerns, Nikolay Yegorov, Deputy Minister of Atomic Energy responsible for plutonium disposition, rated the VVER option as "highly doubtful". Yegorov has also raised the possibility of sale of plutonium to Europe, Canada or other countries for use in their reactors.[20] Russia will probably have to immobilize the part of its plutonium surplus that is too impure to easily manufacture into MOX fuel. How much of the surplus is impure is unknown. As a rough guide, the United States expects that as much as one third of its own plutonium surplus stockpile will be too impure to fabricate into MOX fuel.[21] Disposition is not a permanent solution to the security problems raised by the existence of plutonium. Because the dominant source of radioactivity in the dispositioned waste form, Cs-137, has a thirty year half-life, the radiological barrier will be substantially reduced in about two hundred years. The main barriers to recovery of dispositioned plutonium will then be the expense of reprocessing materials with relatively low radiation emissions, and, if the plutonium-bearing waste is stored in an underground repository, the difficulty of digging it up. Indeed, deep burial of the dispositioned material, as opposed to the physical characteristics of the waste form itself, is regarded by one important DOE study as the dominant factor in deterring access in the long term.[22] Yet this final step is by no means assured, and even if it were, some analysts consider burial alone an insufficient deterrent to recovery.[23]As with dispositioned military plutonium, the radiological barrier against recovery of the plutonium in civil stocks of spent fuel will also eventually decay. Additional action will be required in the long term to ensure the proliferation resistance of all plutonium stocks, whether military or civil, separated or unseparated. For these reasons, disposition should be recognized as a medium to long-term method of plutonium storage in a relatively secure fashion, while society determines what the final fate of all plutonium stockpiles will be. During the approximately ten-year period in which the infrastructure for disposition is being built, and during the execution phase, the surplus plutonium must be securely stored to minimize the threat of theft and terrorist attack. Minatom and other responsible agencies have begun to address the problem of fissile material security generally, in conjunction with the US Cooperative Threat Reduction program and other foreign assistance programs. In addition to these so called 'national' safeguards, international safeguards are needed to detect diversion of the material by the host country. Such safeguards are essential to give some confidence that the two largest weapons states are not surreptitiously maintaining a secret rearmament capability even as they move towards disarmament. In the United States, part (about ten metric tons) of the surplus plutonium stockpile has been placed under IAEA safeguards.[24] (The IAEA is the agency responsible for implementing international safeguards under the terms of the Nonproliferation Treaty.) Russia has also indicated its intention to place some of its military plutonium under IAEA safeguards.[37] THEFT AND RECOVERY OF PLUTONIUM AFTER DISPOSITION Disposition of plutonium would reduce the risk of two distinct possible occurrences:
The radioactive dose and the large size of the dispositioned waste form are the two principal deterrents to theft. The radioactive dose is the most significant barrier to recovery and reuse, since it means that extraction of plutonium must be done with remote handling equipment, greatly increasing the expense and time of recovery. The degree of dilution of the plutonium and the difficulty of the chemical recovery process are also deterrents to both theft and recovery. In addition, political and legal barriers may have some effect on reuse by the owner country. The ease of recovery also depends on who is doing the recovering. A country with no plutonium processing infrastructure that acquired dispositioned plutonium would have to construct a spent fuel reprocessing plant, or a similar plant for recovery of plutonium from glass. This could take a year or longer depending on the technical sophistication, wealth and industrial base in the country.[25] At the other extreme, Russia and the United States already have the infrastructure and a great deal of experience in plutonium recovery, meaning a new arms buildup by those countries using plutonium is always possible. However, such a reversal will be more expensive and somewhat slower than if the surplus plutonium remains in separated form. Moreover, because of the industrial activity required, it will be somewhat easier to detect. Nuclear materials that are "not readily separable from other radioactive material, and that have a total external radiation dose rate in excess of 100 rems per hour at a distance of 3 feet" [26] are defined as self-protecting. By this measure, spent fuel and immobilized plutonium will remain self-protecting for about one to two hundred years.[27] This criterion has been adopted by the DOE in setting the level of radiological protection for dispositioned plutonium.[28] However, an independent vulnerability assessment produced by the DOE notes that 100-200 rem doses are rarely fatal, and that a thief willing to accept a dose up to about that level could steal a dispositioned plutonium waste form[29]. The thief would still be faced with removing a fuel assembly or immobilized waste form weighing from one half to several tons with a volume of a few cubic meters, but fresh fuel assemblies with these dimensions have been stolen from nuclear power plants in the past, such as the 1992 theft of an assembly from the Ignalina nuclear power plant in Lithuania. Formal pronouncements and activities relevant to plutonium disposition have come primarily from the United States. Of these, the most significant is the January 1997 Record of Decision (ROD) issued by the US Department of Energy. That document laid forth the US "dual-track" proposal for plutonium disposition, in which some of the 38 metric ton US surplus would be fabricated into MOX fuel for use in commercial US LWRs or Canadian CANDU reactors, and some (at least 8 metric tons) immobilized. The dual-track proposal has been criticized by arms control activists, NGOS, and in some cases Russian and US government officials themselves, who believe it gives political and economic support to Russia's and other countries' plans for a closed nuclear fuel cycle, as well as encouraging a closed fuel cycle in the US. At the April 1996 Moscow Summit on Nuclear Security, the G7 and Russia issued a nuclear safety and security declaration, which states: This (surplus) fissile material should be safely, affordably, and effectively stored and handled under physical protection, accounting and control measures that meet the highest international standards and that ensure effective non-proliferation controls, until it can be transformed into spent fuel or other forms equally unusable for nuclear weapons or other nuclear explosive devices and safely and permanently disposed of. In September 1996, then IAEA Director general Hans Blix arranged for tripartite talks between Russia, the United States and the IAEA, with the purpose of obtaining a formal identification of the IAEA as the inspectorate responsible for safeguards and inspections of excess plutonium stocks in both countries.[30] IAEA participation is significant because much of the benefit of disposition derives from the confidence it gives the international community that the United States and Russia are genuinely committed to nuclear disarmament, per their requirements under the Nonproliferation Treaty. However, the presence of the IAEA also complicates the disposition campaign, inasmuch as Russia and the United States would have to reveal sensitive information about weapons components not merely to another weapons state, but to an independent international body. Also in September of 1996, the US-Russian Independent Scientific Commission on Disposition of Excess Weapons Plutonium released an interim report,[31] produced at the request of Russian President Boris Yeltsin following an October 1995 meeting with President Clinton.[32] The report called for more rapid action and increased funding for plutonium disposition activities by both the United States and Russia. It further recommended the use of the dual track option for both countries, and called for standards of protection control and accounting of the plutonium and levels equal to those applied to intact nuclear weapons. In addition, it recommended that both countries allow for increased transparency about inventories and suggested that the end goal of the program be "to reach equivalent remaining quantities of plutonium and HEU in the two military stockpiles." A final version of the report was released in June 1997. The final version includes an annex that provides more detail on the steps needed to implement the conclusions reached in the interim report, including a time line for both the immobilization and MOX options. In July 1997, President Yeltsin called for the formation of an ad hoc group to determine the fate of surplus military plutonium.[33] The commission is to be headed by Academician Yevgeniy Velikhov, member of the Russian Federation Defense Council and President of the Kurchatov Research Institute. INFRASTRUCTURE, TIMING, AND COST There are three principal sources of cost and timing estimates for plutonium disposition: the US-Russian Independent Scientific Commission Report, the 1994 NAS study of plutonium disposition, and a DOE technical summary report. The DOE report refers primarily to the timing of activities in the United States, but is useful for comparison purposes since the programs are expected to proceed in parallel. In the absence of political or economic obstacles, the program would begin within five to ten years of a go-ahead from the government, and be completed in about two to three decades, depending on the choice of technology and on the outcome of various technical studies. For the campaign to be effective, the time to startup and time to completion must both be as short as possible. A fast startup time is necessary to indicate that both Russia and the United States are serious in their efforts to lock in arms reductions through the disposition campaign. A fast completion time is particularly important for Russia, where the political situation is less stable and security of fissile materials less assured than in the United States. The cost of the campaign will range from about $1 billion to several billion dollars depending on the disposition method used. Time and cost estimates are discussed in more detail below. Costs in Russia are somewhat less than in the US. The NAS study has used an approximate figure of a two thirds reduction in cost.[34] The cost estimates below which refer explicitly to Russia reflect this estimated reduction. Technical uncertainties in both technologies that may affect both cost and timingare discussed in a separate section. Reactor Options For the MOX option, plutonium disposition in Russia will require:
Overall Time and Cost Estimates for the MOX Option The estimated total cost of reactor disposition in Russia ranges from $0.84 to $2.2 billion. The total time for reactor disposition is estimated to be from 15 to 30 years (with the shortest estimate assuming the use of 12 reactors). The DOE estimates a 10-year lead time prior to irradiation of the first MOX fuel assembly in a reactor.[35,36]More details on infrastructure, timing and cost of the MOX option are discussed in a separate section. Existing Infrastructure Russia has one breeder reactor and 7 VVER-1000 light water reactors that may be suitable for plutonium disposition. It has no pit conversion facilities and only pilot scale MOX fabrication plants. Immobilization Options Immobilization requires a plant to convert plutonium from metal to oxide (or alternatively to the liquid nitrate form) and an immobilization plant. Either ceramic or glass can be used as the immobilization medium. Russia has a large-scale high-level waste vitrification (glass) plant at the Mayak Chemical Combine that could be adapted to the plutonium disposition program. However, neither Russia nor the United States has vitrified or otherwise immobilized plutonium on the required scale. High-level radioactive wastes typically contain only trace quantities of plutonium, up to about 0.01 percent, while plutonium vitrification would require percentages of about 5 to 10 percent.[37] DOE officials have stated that anywhere from 8 to 17.5 metric tons of the 50 metric ton plutonium surplus are in impure non-pit forms that will probably require immobilization. [38,39] The amount of impure plutonium stocks in Russia is unknown, but may be comparable. Overall Time and Cost Estimate for Immobilization The DOE estimates that immobilization of 50 metric tons of plutonium in the United States could begin in seven to 12 years, and be complete in 18 to 21 years.[36] The time variation depends on whether or not existing facilities and the relatively simple can-in-canister method can be used. Similar times should apply for Russia, since the use of existing facilities and the can-in-canister method are possible there as well. The Independent Scientific Commission estimates a startup time of about seven years in both Russia and the United States.[40] Russia is unlikely to immobilize all 50 metric tons of its military plutonium surplus, therefore less time will be necessary for the execution phase there. The DOE TSR cost estimate for conversion to oxide and immobilization is $1.8 to $5.1 billion dollars,[41] the price variation again depending upon whether existing facilities and the can-in-canister method may be used. Scaled down to reflect lower costs, this amounts to $1.2 to $3.3 billion in Russia. Existing Infrastructure A large-scale vitrification facility was in nearly continuous operation at Mayak from 1991 to 1997. As of February 1997, the plant was shut down, with plans to replace its central component, the glass melter. The single-stage melter has vitrified 285 MCi of HLW since 1991. About one metric ton of high-level waste-bearing glass is produced per day.[42] Assuming this rate of vitrification, 50 metric tons of plutonium oxide could be incorporated into the waste at the level of 5 percent by weight in five years. The Mayak plant would require substantial modification to accept plutonium, and research would be required into the amount of plutonium that could safely be added to the HLW bearing glass. As discussed earlier, plutonium could be immobilized directly with HLW, or via the two stage can-in-canister method. Level of Self-Protection Because the HLW that is used to provide a radiological barrier was separated from (self-protecting) spent fuel as that fuel was reprocessed for plutonium, it is approximately true that there is as much HLW as is necessary to provide a self-protecting dose for all stocks of plutonium produced. (Thus the immobilization process is sometimes referred to as "anti-reprocessing".) However, since some HLW in Russia has already been vitrified or otherwise discarded, and since the radiological dose is sensitive to the geometry of the waste form, it is important to verify that there is sufficient supply of Cs-137 to allow for self-protection of the military surplus. So far, about 140 MCi of liquid HLW has been vitrified, with some 570
MCi of liquid waste remaining in the tanks at the Mayak Combine. Assuming
that this waste is derived primarily from VVER fuel reprocessing, Cochran
et. al. estimate that 83.3 kCi/metric ton of the radioactivity comes from
Cs-137 [43]. As of 1995,
about 3000 metric tons of fuel had been reprocessed at Mayak [44],
implying a Cs-137 stockpile of about 250 MCi. Assuming a waste form
similar to the glass log used in DOE and NAS calculations, this amount
of Cs-137 is sufficient to provide a self-protecting radiological dose
(see above) for 100 years for approximately 100 metric
tons of plutonium.[45] There are
also large amounts of Cs-137 at the Tomsk-7 and Krasnoyarsk-26 plutonium
production facilities. Thus there is an ample supply of Cs-137 available
for use in the disposition process.
Comments or questions? Contact Elena Sokova at MIIS CNS: esokovaATmiis.edu 
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