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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM Chapter 1: Context 1.1. URGENCY AND PROBLEM During the Cold War an unprecedented build-up of nuclear weapons took place in the United States and the Soviet Union. Whatever the justification for such a build-up, the end of the Cold War made extensive nuclear arms reductions possible. In the START I Treaty, now in force, and the START II Treaty, not yet ratified, the United States and Russia have agreed to reduce their strategic arsenals from over 12,500 and over 10,500 warheads, respectively, to approximately 3,500 warheads each by the year 2003. Unilateral initiatives by Presidents Bush, Gorbachev, and Yeltsin provided for reductions in tactical weapons at a similar rate. Although these treaties and unilateral initiatives do not require the actual dismantlement of the warheads themselves, both sides acknowledge the need to do so, and both have started dismantling at comparable rates. Dismantlement is also expected by the international community as concrete evidence of the U.S. and Russian commitment to arms reduction. This dismantlement will result in substantial quantities of fissile materials, which are the essential ingredients of nuclear weapons. Access to this material—weapons-grade plutonium (WPu) or highly enriched uranium (HEU)—is the primary technical barrier to acquiring a nuclear weapons capability. Neither the United States nor Russia has made an official statement of how much WPu or HEU it will declare excess to its military needs. But the two countries are considered likely to declare excess well over 100 tons of WPu and well over 1,000 tons of HEU in the next decade. As a practical working figure, the release of about 100 tons of WPu by Russia in perhaps 10 years is widely accepted and will be used throughout this report. Since as little as 4 kilograms of WPu or several times that amount of HEU is sufficient to make a nuclear explosive, these numbers indicate the magnitude of the problem. These materials are a “clear and present ” danger to international security. They could quickly end up in nuclear weapons again in the hands of the state that owns them, or they could substantially shorten the time scale of a proliferating state’s nuclear weapons program, or they could even find their way into the hands of terrorists. Therefore the management and disposition of excess WPu and HEU must be designed to minimize the risks that these materials again become components of nuclear weapons. Minimizing the dangers to international security posed by these materials is also clearly in the interest of Russia’s Western partners, including Germany. This report has a specific goal: to provide recommendations for Germany’s contribution, in cooperation with the United States, to accelerating the process leading to the disposition of excess weapons plutonium in Russia and to enhancing the security of the steps leading to that goal. The report concentrates on the management and disposition of WPu because solutions for HEU are technically much easier and the implementation of these solutions is already more advanced. The search for workable solutions that are acceptable to Russia, the United States, Germany, and the international community is not trivial because the nuclear policy framework is different in each country. Moreover, opinions and interests vary among diverse parties within each coun-
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM try, such as the nuclear industry, the national security community, various parts of the government, and the public. As a result, proposals for solutions to mitigate the “plutonium glut” may differ considerably among countries and within each nation. The exclusive target of this report will be the search for improvements in international security through optimum management of excess fissile material and its disposition. While we will avoid choices among options for the civilian nuclear fuel cycle, such options must be considered as part of the context for judging the feasibility and acceptability of alternate options for plutonium management and disposition. The report consists of two main parts. The first describes the context in which German-U.S. collaboration can take place. We will identify the policies, experience, and interests of the United States, Russia, and Germany. We will assess the nuclear disarmament process already under way and the activities through which the United States and other Western countries are cooperating with Russia to improve the security of the plutonium management and disposition process. The second part of this report investigates possibilities for German participation, both independently and in cooperation with the United States. First some underlying principles are established, defining the goals and the framework of collaboration between Germany and the United States. Recommendations are aimed at enhancing international security and are not influenced by the ongoing German domestic debates over nuclear energy, or by additional market opportunities for the nuclear industry. Several options for collaboration are identified, and their advantages and disadvantages are evaluated. The primary criterion used in this evaluation is the security risks of various options; the feasible time scales considering Russian, U.S. and German conditions, political acceptability to the major actors, potential effects on the environment and public health, and rough cost estimates are important criteria as well. This evaluation results in a list of recommendations relating to the potential German role. In identifying options for German-American collaboration in support of Russian weapons plutonium activities, the Steering Group has not identified the cost of the various options. Some specific cost figures are given for various steps for purpose of reference. The responsibility for the management and disposition of the weapons plutonium released from excess nuclear warheads in the former Soviet Union rests with Russia, the owner of these weapons, but in the present economic situation it is not expected to achieve this formidable task without major support and assistance from the Western powers. The general judgment is that the cost to be borne by them for this purpose will be in the range of several billion dollars, spread over the next ten years. How such costs shall be borne by the nations concerned is, of course, a matter of international negotiations.1 We point out here, however, that this total cost is an exceedingly small fraction of the sums the world is expected to spend in the name of international and national security during the same period. 1 The actual components of the costs of the reactor-related and vitrification options are by their nature uncertain, and depend on the specific conditions of the work to be undertaken. These issues are discussed in detail in a report by a special panel of CISAC. See National Academy of Sciences, Committee on International Security and Arms Control, Management and Disposition of Excess Weapons Plutonium: Reactor-Related Options (Washington, D.C.: National Academy Press, 1995).
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM 1.2. RELEVANT EXISTING STUDIES 1.2.1. The National Academy of Sciences Study The Steering Committee has agreed to use the findings of the report of the National Academy of Sciences’ Committee on International Security and Arms Control, Management and Disposition of Excess Weapons Plutonium, as the technical basis for the recommendations provided by this study.2 Appendix A presents the complete Executive Summary of the National Academy of Sciences (NAS) study. The NAS report identifies the technical and political problems of the disarmament process and the domestic nuclear energy infrastructure of the United States and Russia. It provides a road map for making decisions about all the steps for plutonium disposition. This section summarizes the conclusions of the NAS report as they relate to this report. A key recommendation is that, throughout the management and disposition process, technical, as well as political, barriers should be erected that minimize the risks that fissile materials might be returned to military use. These risks are “breakup,” “breakdown,” and “breakout.” “Breakup” denotes the risk that Russia might split up into several nuclear-armed nations, distributing the weapons-usable nuclear material among different sovereign states. “Breakdown” means the risk that the security system and physical protection of the weapons and the weapons material in Russia do not adequately function, so that unauthorized diversions and criminal transfers might increase. Illegal trafficking of radioactive materials has already substantially increased in the last several years. “ Breakout” means a change in Russian policy that reverses the current disarmament process and shifts back to the reconstruction of a larger nuclear arsenal. Due to the different technical properties of the two weapons-usable materials, HEU and Plutonium, their management and disposition pose different problems. For HEU a technical solution is readily available; HEU can be blended down with sufficient quantities of natural uranium, uranium of very low enrichment, or even depleted uranium, to convert it into low enriched uranium (LEU), which is the fuel used in most of the world’s nuclear power reactors. LEU is uranium containing less than 20 percent of the isotope U235. It is impossible to use such a mixture as nuclear bomb material, and re-enriching LEU back to weapons-usable form requires sophisticated technology that is not widely available. The United States and Russia have signed agreements for the United States to purchase 500 tons of HEU, blended down to LEU, for eventual sale as fuel for nuclear power reactors, although serious disagreements over pricing remain. A similar course does not exist for plutonium because all isotopes 3 of plutonium are fissionable. Plutonium is a man-made element, which is generated in nuclear reactors when uranium is exposed to intensive neutron bombardment. The amount of the resulting plutonium and its isotopic composition depend on the length of time the uranium fuel is bombarded in the reactor before being withdrawn. Isotopic dilution therefore cannot be the answer for plutonium that “denaturing” is for HEU. Broadly speaking, there are two classes of plutonium: WPu and reactor-grade plutonium (RPu). WPu is withdrawn from the reactor at low burn-up and consists 2 National Academy of Sciences, Committee on International Security and Arms Control, Management and Disposition of Excess Weapons Plutonium (Washington, D.C.: National Academy Press, 1994). 3 One isotope of plutonium (Pu238), if present in an isotopic mixture in sufficient quantities, would make weapons use extremely difficult but not enough of that material is available.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM FIGURE 1 World Plutonium Stockpiles * Includes weapons and weapon components from weapons already dismantled. Source: CISAC estimates, based on David Albright, Frans Berkhout, and William Walker, World Inventory of Plutonium and Highly Enriched Uranium 1992 (Oxford: Oxford University Press for the Stockholm International Peace Research Institute, 1993); J.S. Finucane, “Summary: Advisory Group Meeting on Problems Concerning the Accumulation of Separated Plutonium” (Vienna: International Atomic Energy Agency, September 21, 1993); and U.S. Department of Energy press release, December 7, 1993. mainly of the isotope Pu239 (about 94 percent or more); RPu results from more complete burn-up and contains only about 60 percent Pu239. The other isotopes are mainly the heavier Pu240and Pu241. The isotopes other than Pu239, although in themselves fissionable, have characteristics which makes them less desirable for the construction of nuclear weapons. For these technical reasons the nuclear weapons states utilize WPu for their nuclear explosives. But if only RPu were available, nuclear weapons could be produced using elementary designs which would have an assured yield between one to two kilotons.4 More sophisticated designs using RPu could be developed with even higher assured yield. The diversion of plutonium of any composition must therefore be regarded as a serious proliferation danger. This includes spent fuel from civilian power reactors, particularly if the plutonium from such spent fuel has been separated (reprocessed). Approximately 1,000 tons of RPu are contained in spent reactor fuel, as much as ten percent of which has been reprocessed. Figure 1 gives an overview of the worldwide plutonium inventories that are expected in the year 2000. 4 E. Kankeleit, C. Küppers, U. Imkeller, “Bericht zur Waffentauglichkeit von Reaktorplutonium” (Report on the weapons usability of reactor-grade plutonium), Report IANUS-1/1989, and C. Mark, “Explosive Properties of Reactor-Grade Plutonium,” Science & Global Security, 4:111–128, 1993.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM The NAS study lists seven categories of plutonium and HEU, ranging from military Pu and HEU in operational nuclear weapons, through other forms of military plutonium, such as reserves or scrap, to plutonium and HEU currently in reactors, and spent reactor fuel. The NAS study concludes that the lowest risk category of plutonium is that contained in radioactive spent fuel, from which it is difficult to extract. The radioactive protection and the reprocessing technology needed to separate it from the radioactive fission products constitute a higher barrier to potential proliferators than the technical difficulties arising from the different isotopic composition of RPu compared to WPu. Both the NAS study and this study focus only on the problem of management and disposition of excess weapons plutonium. Since all forms of plutonium pose proliferation risks, the NAS study concluded that it would not be sensible to define standards of proliferation resistance for the excess WPu higher than that of the much larger quantities of plutonium in spent fuel. Accordingly, the NAS study recommended two security standards for judging the risks during the management and disposition process: The Stored Weapons Standard: Dismantlement, storage, and disposition will require handling and transportation steps that could increase the risk of theft or diversion of the fissile materials. Therefore, high security and accounting standards, as close as possible to those applied to intact nuclear weapons, must be maintained through all stages of the process. The Spent Fuel Standard: The options for long-term disposition should make the weapons plutonium roughly as inaccessible as the much larger quantities of plutonium in civilian spent fuel. Options that left the plutonium more accessible would mean that it continued to pose a unique security risk indefinitely, while going beyond the spent fuel standard to eliminate the weapons plutonium completely would not be justified unless the same approach were applied to the world’s entire stock of plutonium. The NAS report concluded that, over the longer term, steps beyond the spent fuel standard to reduce the proliferation risk of both military and civilian plutonium stocks will be needed. The NAS study divides the steps in managing and disposing of excess weapons plutonium into the first four phases shown in Figure 2. Each of the phases requires a range of political and technical measures that must meet the security standards described above. In a first phase, the United States, Russia, and the international community are working to create a regime of enhanced transparency for the stockpiles of all fissile materials. The second phase is the dismantlement of the warheads. The third phase is the intermediate storage of the resulting components containing plutonium, and the fourth is the technical process leading to long term disposition. This report adds a fifth phase to the categories in the NAS study —a second period of intermediate storage, provided that the material or items resulting from the disposition process meet the spent fuel standard. In the sixth and last phase such materials will be put into a final geological repository. The time scale of the management and disposition process necessarily extends over several decades and the phases overlap to a considerable extent. Intermediate storage begins as soon as the first warheads are dismantled, for example. Furthermore it is unlikely that the disposition phase can commence in less than ten years. The length of the disposition campaign, depending on the method chosen and on the total quantity of resources applied, will extend for at least a decade. Final geological disposal is unlikely to be available before 2015 in the United States, and similar dates apply to other countries.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM FIGURE 2 Phases of Plutonium Management The chart tabulates the phases of plutonium management which are to some extent overlapping. The first four phases are those described in detail in the NAS study. Should the preferred disposition options —Fabrication of MOX fuel which is then consumed in a “once-through” fuel cycle in existing LWRs or HWR (CANDU) or vitrification with high-level waste—be implemented, the resultant product must be stored again until the last phase—deep geological disposal—becomes available.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM The earlier phases of dismantlement and storage are at least as important —and represent a more immediate security risk—than the later phases. Although weapons and fissile materials in the former Soviet Union are currently of greater concern than those in the United States, reciprocity will be generally necessary in order to gain Russian acceptance. The security and transparency of all phases should be enhanced with technical and structural improvements for material protection, control, and accounting (MPC&A). 1.2.2. The Status of the Implementation of the NAS Study Recommendations Declarations and Transparency The NAS study recommended that the United States should work to reach agreement with Russia on a new, reciprocal regime that would include: (a) declarations of stockpiles of nuclear weapons and all fissile materials; (b) cooperative measures to clarify and confirm those declarations; (c) an agreed halt to the production of fissile materials for weapons; and (d) agreed, monitored net reductions from these stockpiles.5 Some bilateral progress between the U.S. and Russia on the first phase has already been made, and most of the remaining issues are being negotiated. Presidents Clinton and Yeltsin agreed to declare stockpiles of nuclear weapons and all fissile materials at the summit in September 1994, but the agreement has not yet been implemented. The United States has made declarations of its total WPu inventories unilaterally. The United States has proposed cooperative measures to clarify and confirm the declarations for fissile materials (but not for warheads), but these have not yet been negotiated. No military HEU production is taking place on either side. The two countries agreed in principle to halt the production of plutonium for weapons in June 1994 but this has as yet not entered into force. U.S. production has already halted, and Russia has agreed to halt production by the year 2000. The continued WPu production is taking place in three reactors in Tomsk and Krasnoyarsk, which are operated primarily to produce heat and electricity for the towns and jobs for the workers. Each side has proposed variants on plans for agreed, monitored net reductions from their stockpiles of fissile materials, but as yet there is no agreement. Negotiations between the United States and Russia to make formal commitments that specific quantities of fissile material from dismantled weapons will be declared excess and committed to non-weapons disposition are under way, but the amounts of material remain a key open issue. Neither side has yet fully accepted that the standards leading to the disposition processes should come as close to the stored weapons standard as possible. 5 NAS (1994), op. cit., pp. 1–2.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM As yet there is no progress toward the longer-term goal of enlarging any bilateral regime into a worldwide regime with higher standards of security and transparency for all military and civilian fissile materials stocks worldwide. Only limited progress has been made on the proposal to declassify information concerning the total stockpiles of weapons and fissile materials, and the technical characteristics necessary for external monitoring. The U.S. Congress has laid the foundation for reciprocal transparency, however, by permitting the negotiation of agreements between Russia and the United States to share still-classified data. The Cooperative Agreement required by the legislation has not been reached between the two countries, and this constitutes a key limiting factor on many transparency efforts. Dismantlement In the United States, warhead dismantlement consists of several steps. As a first step, all control components are removed. Then the fissile and non-fissile components are separated from each other, and the non-fissionable components are generally deformed into unclassified forms and then placed into appropriate waste streams. Tritium is recovered and stored for reuse in remaining warheads. The fissile components, the so-called “pits,” consist of a hollow sphere made from plutonium, HEU, or both, encased in an inert sealed envelope. All technical details on the configurations and compositions of pits are classified. Declassifying large parts of this information is not desirable for nonproliferation reasons and therefore is not acceptable to either the nuclear or the non-nuclear weapons states. In the United States, dismantlement takes place at the Pantex facility near Amarillo, Texas, at rates approaching 2,000 warheads per year. Dismantlement in Russia is reportedly taking place at four different sites at comparable rates. Repeated reports from Russia claim that storage capacity for components at these sites is at its limits and that workers at the facilities frequently go unpaid because there is no money for salaries. While both sides have declared that the dismantlement process is already under way, the only actual example of monitoring is Ukrainian observation of the dismantlement of warheads from Ukraine. This is being carried out by inspectors who were scientists or technicians in the nuclear weapons complex of the former Soviet Union, and are already familiar with the classified details of Soviet weapons design. The NAS report proposed an agreement for perimeter-portal monitoring of dismantlement facilities, counting warheads entering these facilities, and assaying the fissile material that leaves. This has not been formally proposed by either side. In principle, both sides have agreed to monitor components, but as yet no detailed arrangements have been implemented. In December 1994, the United States proposed to monitor weapons before dismantlement and to construct a “paper trail” to the components afterwards. Intermediate Storage The security of the third phase, intermediate storage, is of great importance because the implementation of any disposition option will take substantial time—at least one and probably several decades. This is much longer than the time for which political developments in Russia, and
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM possibly in other relevant regions, can be predicted. There are a variety of options for the storage of weapons components, but no final decisions have been made on any of them. Technically, the HEU and WPu could be stored as intact, deformed, or sliced pits, or as oxides, ingots or other forms. In Russia, further transformation of the pits is possible, since warhead factories there are still active. The only U.S. fabrication facility, at Rocky Flats, Colorado, is decommissioned, however, so the United States does not have a ready possibility of modifying any large quantity of pits. It should also be noted that a substantial fraction of total WPu holdings in both countries exists in scrap and various other forms, rather than in pits. The greater the effort needed to reuse the stored material in warheads, the higher the proliferation resistance of the storage appears to be. Leaving the pits intact would also send a signal of reversibility, perhaps causing others to doubt the U.S. and Russian commitment to arms reduction. On the other hand, intact pits are physically very stable, since they are surrounded by inert metal shells. Accounting for them is also simple. Deforming, or otherwise modifying pits, could pose risks for the environment, safety, and health (ES&H) that would need to be overcome. The NAS report recommended that plutonium from dismantled warheads should continue to be stored as intact pits for now, but modification to make reuse more difficult should be undertaken if it can be accomplished at relatively low cost and ES&H risks. Finally, the time needed for a proliferator to fabricate new pits from plutonium in other forms is not likely to be a controlling factor for production of a deliverable nuclear weapon. An essential feature of intermediate storage should be that material can only be withdrawn for civilian uses with international safeguards, and the NAS report made a number of proposals toward that end. Both sides appear to accept the idea that storage should not be indefinite. The U.S. Department of Energy (DOE), and apparently the Russian Ministry of Atomic Energy (MINATOM), accept that appropriate arrangements for intermediate storage are to a large extent decoupled from long-term disposition decisions and should be considered more urgent. Originally, the United States planned to provide assistance to Russia in designing and constructing a facility to consolidate all excess materials at a single site. This assistance has only been partially delivered and, given local opposition among other factors, it now seems unlikely that there will be a single site for storing all the materials. As yet, the United States has not offered financial or other incentives that might encourage Russia to place the maximum amount of material into monitored storage. (The NAS report noted that, if the United States does so, there should be no side conditions that provided an incentive for continued production of separated plutonium.) To date, neither side has accepted that pits should be stored in sealed containers, with monitors permitted to assay the containers externally without observing the pits’ dimensions for the purpose of safeguards. The United States proposed in December 1994 that the International Atomic Energy Agency (IAEA) should be rapidly brought into the process of monitoring intermediate storage, but Russia seems unwilling to accept this in the near term. Some increase in the U.S. contributions to the IAEA has taken place, including funding of safeguards for U.S. excess materials. But overall, the IAEA safeguards budget remains too small
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM for major added missions, and other steps needed to strengthen that organization’s capabilities have not been taken. Disposition The NAS study divides the options for plutonium disposal into three categories: Indefinite storage, which would create a barrier to military reuse based solely on policy and security measures, not on fundamental technical barriers. It would require substantial physical protection and other security and nonproliferation measures. The NAS study rejects this option as too great a proliferation risk, and as not satisfying the requirement to pose an additional barrier to reuse in weapons. Minimized accessibility, which would create radiological, chemical, or physical barriers to reduce the availability for weapons use. Several methods belong to this category. They can be divided into those that make civilian use of the material in nuclear power reactors and those that do not make any use of the energy content of the WPu. The latter includes vitrification, deep borehole disposal, underground nuclear explosions that mix the plutonium with melted rock, sub-seabed disposal and repository burial. Elimination, which would remove the material nearly completely from human access. This includes options such as burning it completely in reactors by many repeated fuel cycles (consequently needing reprocessing), launching it into deep space, or diluting it in the oceans. Achievement of elimination is more costly, complex, time-consuming, and risky than minimizing accessibility to meet the “spent fuel standard ” described previously. Elimination can only be justified if it is applied to all plutonium, civilian and military. Given the divergence of worldwide policies concerning the civilian role of plutonium in nuclear power, no decision on elimination is possible, probably for a very long time. Thus, at this time, disposition should aim at minimizing accessibility in order to meet the “spent fuel standard,” not at elimination. For these reasons the NAS study narrowed its recommendations for long-term disposition to two options as the most promising: fabrication of WPu into mixed uranium-plutonium-oxide fuel (MOX) and its use as fuel in existing or modified nuclear reactors, or vitrification in combination with high-level radioactive waste. These options meet the “spent fuel standard” and they are technically advanced enough so that the time during which the material is stored in weapons-usable form can be minimized. The NAS study explicitly concluded that construction of new reactors could not be justified for the disposition of WPu, because existing reactors could do the job more quickly and with greater technical certainty. The MOX and the vitrification options are described in Section 1.3, and more detail is provided in Appendices B and C respectively. It is likely to be 20 years or more before a geologic repository will be ready to receive nuclear wastes of any kind, whether spent fuel or glass logs. Therefore, the material will have to be stored in engineered facilities until a geologic repository is ready to receive it. The radiological
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM barrier provided by the products resulting from the two disposal options meeting the spent fuel standard is essential during this second storage period. 1.2.3. The German/Russian Study On December 16, 1992, a joint German-Russian feasibility study was created at the request of the German Foreign Office (Auswärtiges Amt, AA), which was to study the possibility of producing MOX using WPu and to explore its suitability for the civilian nuclear power industry. The study was carried out by a joint expert group with personnel from the Konsortium Gesellschaft für Anlagen- und Reaktorsicherheit (GRS), the Siemens Company, and MINATOM.6 The study was based on the Russian position that the energy value of weapons plutonium should not be lost in disposition. The study included the possibility that MOX fabricated from WPu might be used in fast neutron reactors, including the breeder, as well as in thermal reactors.7 The joint study implied that the plutonium in the spent fuel was not suitable for weapons.8 The German-Russian study agreed that the use of MOX fuel offered several possibilities for cooperation that would advance disarmament and transformation of WPu into material suitable for civilian nuclear power. The study therefore recommended technical cooperation in producing MOX and in establishing appropriate safeguards. The group recommended against completion of the unfinished MOX fabrication facilities in Russia because these do not meet acceptable standards of safety and are not suitable for the fabrication of light water reactor (LWR) fuel. Instead, the group recommended cooperation in all phases from planning and design to construction of a pilot plant for fabricating MOX in Russia with the capacity to consume one ton of WPu per year. It also recommended that such a pilot plant should meet both Western and Russian standards of safety and that the design should rest on both German and Russian experience. The study estimated that such a pilot plant would cost DM 90 million. The group recommended that, in parallel with designing and building a pilot MOX fabrication plant, the suitability of Russian reactors for burning MOX should be explored, including the VVER 1000. In principle MOX fabricated from WPu should be usable both in Russian and Western reactors, but more detailed examination is necessary. It noted that the geometrical properties of MOX fuel fabricated for German and Russian reactors would be quite different. The group surveyed the available Russian and German reactors and computed the length of the campaign needed to consume 100 tons of WPu under various assumptions of reactor availability and MOX loading. In particular, burning MOX in four modernized VVER-1000 reactors 6 The report will be published under the title Technische Studie über die Produktion von Uran-Plutonium-Brennstoff aus waffengrädigem Plutonium und über die Möglichkeiten seines Einsatzes in der Kernenergiewirtschaft (Technical Study on the Production of Uranium-Plutonium-Fuel from Weapons Grade Plutonium and on the Possibilities of its Use in Civilian Nuclear Energy). 7 Note that the NAS study concluded that, for the disposition option involving reactors, only existing or modified thermal reactors should be used. 8 This conclusion: “Ein grosser Teil des waffengrädigen Plutoniums kann damit zur Energieerzeugung verwendet und dadurch for Waffenzwecke unbrauchbar gemacht werden” differs from the NAS study which concluded, on the basis of a detailed independent study, that spent fuel was difficult to access, but that if the plutonium in spent fuel were reprocessed, the resulting reactor-grade plutonium metal could be used for weapons by a proliferator or terrorist.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM in Balakovo appears feasible. The use of WPu-MOX in the fast reactor BN600 without the breeding blanket, which would make more plutonium, should also be possible. The German-Russian study recommended further collaboration. Our study included the results of this cooperative analysis in its deliberations and recommendations, outlined later in the report. 1.3. OVERVIEW OF TECHNOLOGIES FOR POTENTIAL COLLABORATION Following the conclusion of the NAS study, in this report we will consider only MOX use in thermal reactors and vitrification as appropriate routes for the disposal of WPu. As noted above, Appendices B and C provide a more detailed technical description of these approaches and outline the record of experience with these methods to date. 1.3.1. WPu Disposition Using MOX Nearly 80 percent of the 419 nuclear power reactors operating worldwide at the end of 1993 were LWRs; their fuel is generally low enriched uranium (LEU). Extensive experience in Europe has shown that a mixture of oxides of RPu and uranium (MOX) can also be used as fuel, with up to one-half of the LEU fuel rods replaced by rods fabricated from MOX. Technically it is clearly feasible to fabricate MOX from WPu; in fact there are certain advantages to doing so because of its lower radioactivity. Figure 3 shows three paths by which fuel for LWRs can be provided: Mine uranium, process it into a form suitable for enrichment; enrich the material to about 3-percent U235; fabricate the resulting LEU into fuel elements suitable for LWRs. Obtain surplus WPu; convert it into oxide and fabricate it into MOX, together with natural, depleted, or very lightly enriched uranium oxide. Reprocess RPu from spent reactor fuel and convert it into MOX fuel elements. Figure 3 shows the approximate quantities of materials required to arrive at LWR fuel that is equivalent in energy generation to one kg of plutonium. For purposes of illustration, one kg of plutonium generates about one megawatt of electricity (1,000 kW) for one year. We believe that, unless there are hidden subsidies, the first route —direct LEU fabrication— is the least expensive path today for producing nuclear fuel; the WPu route is more expensive even if the WPu is made available without charge; and reprocessing is the most expensive of the three. These relative cost figures will shift over time, perhaps by the middle of the next century, as uranium resources become less abundant and more expensive than they are today. Some estimates presented at the workshop maintain that energy production using MOX from WPu could be profitable even today based on the experience with 1/3 MOX loading in German reactors, on an estimate for the cost of MOX production in the Hanau plant, and on assumptions about the price of the Russian WPu (as master mix), including transportation, compared to the cost of the competing LEU route.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM FIGURE 3 Alternate Paths to LWR Fuel Alternate paths to LWR fuel starting from reprocessed commercial spent LWR fuel, weapons plutonium and LEU generated from freshly mined uranium, respectively. The chart tabulates typical, but by their nature approximate, values of the weights of materials at each stage of the process. The entries are normalized to the equivalent of 1 kg of phtonium or roughly 1 megawatt-year of electricity generation.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM Consumption of either LEU, RPu-MOX or WPu-MOX leads to “spent fuel” which contains unconsumed WPu (for the WPu approach) and plutonium “bred” from U238, together with other heavy metals and highly radioactive fission products. Such spent fuel is highly radioactive (a typical fuel bundle would produce a lethal dose of radiation in a few minutes at a distance of one meter). The spent fuel is stored first under water at the reactor site and then probably later in shielded dry casks. Thus the use of WPu in MOX has diminished the quantity of that material but, more important, has made it essentially impossible to steal from its storage place. That protection decreases over time, however, as the radioactivity declines, so that older spent fuel requires greater safeguarding.9 Selection of this path leading to secure disposal of WPu must address numerous technical issues, which are elaborated in Appendix B, including: How are the operating (including safety) characteristics of various types of LWRs modified by substituting WPu-MOX for LEU? What fraction of WPu can be put into the fuel and how many fuel elements can be placed into a reactor core? What are the additional ES&H risks associated with WPu-MOX use? What are the additional physical protection difficulties associated with transport of MOX to different LWR sites? When can WPu-MOX use start and how long is the disposition campaign? What fabrication facilities for MOX are available? In view of the accumulated experience with RPu-MOX, all the above questions have satisfactory technical answers today, but translating these solutions into actions requires technical decisions and political and licensing actions. The amount of WPu consumed and the amount of RPu remaining in the spent fuel depends on the specific decisions in response to the above questions. However this matter is essentially irrelevant since the RPu in the spent fuel will join the almost 1,000 tons of RPu now residing in the storage facilities adjacent to the world’s commercial nuclear plants. Hence MOX use of WPu in LWRs meets the “spent fuel standard.” Similar considerations apply to MOX use in heavy water reactors, which provide about eight percent of the world’s nuclear power, including all of Canada’s nuclear electricity. MOX can also be fabricated for the so-called fast reactors, but the MOX composition is very different. Since only a few fast reactors exist, or are under imminent construction, we will not consider this approach. Six LWRs of about 1 GW could dispose of about 100 tons of WPu in less than 20 years if all the LEU fuel rods are replaced with rods containing MOX. While full-MOX loading exceeds the commercial experience and the licensing requirements in Europe, analysis indicates that full loading should be technically feasible. If partial loading is adopted, correspondingly more reactors or longer times would have to be involved in the disposition process. 9 The radioactivity decays by an order of magnitude in roughly 20 years.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM 1.3.2. Vitrification of WPu with High Level Waste Past reprocessing of spent reactor fuel for the production of WPu and reprocessing of spent fuel from commercial nuclear power have resulted in large quantities of high-level wastes (HLW), mostly held in liquid form. A large fraction of the world’s effort to dispose of these materials has focused on “immobilizing” them by incorporating these wastes into molten glass. The vitrification option for disposing of WPu is to add one percent or more by weight of WPu to the molten glass, in addition to the HLW. The resultant glass logs can be very heavy (greater than one ton) and their radioactivity will be similar to that of spent reactor fuel. They provide a physical barrier to theft similar to that generated by spent reactor fuel, and thus this disposition option meets the “spent fuel standard.” While a great deal of experience exists with vitrifying HLW, no large-scale vitrification combining both HLW and plutonium has been done. Experimental work is proceeding, however. Several technical questions must be addressed before this disposal method can be adopted, such as: How must the present processes be modified to permit the addition of WPu? How can the risk of criticality (i.e., of a nuclear chain reaction potentially leading to an explosion) be eliminated during the process? How much WPu can practically be added to the glass? Is this fraction large enough so that no additional space in the geological repository will be required? Can assurance be given that differential leaching or some other process in the geological repository will not isolate and concentrate the plutonium, thereby generating criticality risks? When can vitrification of HLW with WPu start and how long will the disposition campaign be? Will the addition of WPu add to the ES&H risks of vitrification of HLW? These questions almost certainly all have satisfactory answers, but additional research and development are required. Further technical details and a discussion of the available experience are given in Appendix C. 1.3.3. Comparison of the MOX and Vitrification Option for the Disposal of WPu While both of the recommended approaches to WPu disposal meet the “spent fuel standard,” which defines the theft resistance of the disposition process, they differ in several essential respects, such as: MOX use preserves the energy content of WPu while vitrification “throws it away.” MOX use has been validated by commercial experience while the vitrification approach requires additional RS&D. The MOX option involves additional costs and proliferation risks because of the physical protection required during fabrication, and these must be reflected in any cost estimates. Vitrification requires fewer steps in WPu handling. Vitrification does not change the isotopic composition in the disposal product while reactor disposition converts the isotopic composition to RPu.
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM MOX use and vitrification send different “signals” with respect to the future of nuclear power: MOX use appears to legitimize the use of MOX fabrication facilities, at least for disarmament purposes, while vitrification avoids the use of WPu in elements of the civilian nuclear power system. Both approaches require financial subsidies in the interest of international security, but the amount of subsidy is not well enough established to constitute a useful discriminant between the two approaches. 1.3.4. Material Protection, Control, and Accounting The proliferation resistance of a disposition option is determined by the form of the material, the physical access afforded by the technology or facility that processes or stores the material, the level of safeguards and security that are applied, and the external and internal threat to the material. Because of the length of time between the current state of the material and disposition, the intermediate steps must be strongly proliferation resistant. The “spent fuel standard ” aims to increase the difficulty of acquiring the material and processing it after disposition. Factors prior to disposition that affect the technical difficulty of acquiring the material include the numbers and types of barriers between the threat and the material, the quality of material protection, control, and accounting (MPC&A), the safeguards, the self-protection properties of the material such as radioactivity, and characteristics of the form such as size and weight. Additional factors in the difficulty of processing the material are the technical complexity due to the concentration of plutonium and the chemical form, the processing time required, and the costs. Physical protection must prevent the theft and diversion of nuclear material by both personnel inside the facility and outsiders, and protect against sabotage. Regulations include requirements for security organization, physical barriers, access systems, communication systems, test and maintenance programs, contingency response plans and procedures, and procedures for movement and removal of material. The system must be multi-layered: it should be effective, even if the primary protection barriers fail. Material control and accounting regulations address requirements for records and reports, procedures, the organizational structure of facilities, measurement systems, measurement control programs, statistical calculations and evaluations, physical inventories, accounting systems, and internal controls. Safeguards provide for independent verification of the correctness of declarations by material control and accounting measures and containment and surveillance. In the United States, the term “safeguards” denotes the sum of domestic MPC&A measures, whereas in the EU and for non-nuclear weapons states party to the NPT, the term does not include physical protection and is reserved for the verification activities of Euratom and the IAEA at civilian nuclear facilities. In Germany, only the responsibility for physical protection rests with national authorities. The regulatory and enforcement authority for material accounting is Euratom. There is no separate national material accounting agency. In contrast to the United States and Russia, all of Germany’s nuclear infrastructure is additionally subject to international safeguards by Euratom
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U.S.-GERMAN COOPERATION IN THE ELIMINATION OF EXCESS WEAPONS PLUTONIUM and the IAEA.10 In the United States, the Nuclear Regulatory Commission (NRC) is in charge of the regulation of MPC&A activities for non-military nuclear activities; MPC&A for defense programs remain the responsibility of DOE. The DOE, the NRC, the IAEA, and Euratom have developed criteria for evaluating the relative attractiveness of nuclear materials for use in weapons. These criteria are generally related to the amount of the material required for a single weapon (“significant quantity”), the time to process the material to a weapons-usable form, and the technical difficulty of processing it to this form. From the beginning of the German civilian nuclear industry the highest standards of MPC&A have been applied. German participation in activities related to managing Russian plutonium will require standards as high as possible and will have the goal of raising existing Russian standards. The U.S. government also stresses the critical importance of maintaining the highest standards of security and accounting for nuclear materials throughout the process in all its discussions of plutonium disposition, regardless of which disposition option is chosen. In the former Soviet Union, accounting for nuclear materials has traditionally been limited; the system was designed to respond to external threats. MPC&A relied on financial and prison penalties in case of failure. The director of a facility was personally responsible, but few additional technical systems would remain functioning when personal responsibilities failed. Security relied on staff who were bound in a closed social system which guaranteed their social safety and which controlled their contacts. But physical protection measures against external threats were strong. Now all facilities face tremendous financial problems and demoralized ill-paid personnel. As a consequence, inside threats stemming from such social problems are becoming real. Although so far none of the known cases of nuclear smuggling involved material directly from the nuclear weapons or reserves, the number of cases of thefts from the civilian nuclear complex or from military non-weapons areas (e.g., from naval nuclear power reactors) has increased in recent years. 10 INFCIRC/193 is the agreement between the IAEA and Euratom that enables the IAEA to carry out inspections in the Euratom non-nuclear weapons states and regulates the safeguards relationship between both organizations. It was amended by the Partnership Agreement of April 1992 between the IAEA and Euratom, which has made the cooperation more effective and more cost effective.
Representative terms from entire chapter: