U.S.-German Cooperation in the Elimination of Excess Weapons Plutonium (1995)

Under the first and second Strategic Arms Reduction Treaties (START I and II) and unilateral pledges made by Presidents Bush, Gorbachev, and Yeltsin, many thousands of U.S. and Russian nuclear weapons are slated to be retired within the next decade. As a result, 50 or more metric tons of plutonium on each side are expected to become surplus to military needs, along with hundreds of tons of highly enriched uranium (HEU). These two materials are the essential ingredients of nuclear weapons, and limits on access to them are the primary technical barrier to acquisition of nuclear weapons capability in the world today. Several kilograms of plutonium, or several times that amount of HEU, are sufficient to make a nuclear weapon.

The existence of this surplus material constitutes a clear and present danger to national and international security. None of the options yet identified for managing this material can eliminate this danger; all they can do is to reduce the risks. Moreover, none of the options for long-term disposition of excess weapons plutonium can be expected to substantially reduce the inventories of excess plutonium from nuclear weapons for at least a decade.

Our study of this problem leads us to the following four principal recommendations:

1. A New Weapons and Fissile Materials Regime. We recommend that the United States work to reach agreement with Russia on a new, reciprocal regime that would include:

   1. declarations of stockpiles of nuclear weapons and all fissile materials;

   2. cooperative measures to clarify and confirm those declarations;

   3. an agreed halt to the production of fissile materials for weapons; and

   4. agreed, monitored net reductions from these stockpiles.

Monitoring of warhead dismantlement and commitment of excess fissile materials to non-weapons use or disposal, initially under bilateral and later under international safeguards, would be integral parts of this regime, as would some form of monitoring of whatever warhead assembly continues.

2. Safeguarded Storage. We recommend that the United States and Russia pursue a reciprocal regime of secure, internationally monitored storage of fissile material, with the aim of ensuring that the inventory in storage can be withdrawn only for non-weapons purposes.

3. Long-Term Plutonium Disposition. We recommend that the United States and Russia pursue long-term plutonium disposition options that:

   1	National Academy of Sciences, Committee on International Security and Arms Control, Management and Disposition of Excess Weapons Plutonium: Executive Summary (Washington, D.C.: National Academy Press, 1994).

1. minimize the time during which the plutonium is stored in forms readily usable for nuclear weapons;

2. preserve material safeguareds and security during the disposition process, seeking to maintain the same high standards of security and accounting applied to stored nuclear weapons;

3. result in form from which the plutonium would be as difficult to recover for weapons use as the larger anf growing quantity in plutonium is commercial spent fuel; and

4. meet high standards of protection for public and worke health and for environment.

The two most promising alternatives for achieving these aims are:

• fabrication and use as fuel, without reprocessing, in existing or modified nuclear reactors; or

• vitrification in combination with high-level radioactive waste.

A third option, burial of the excess plutonium in deep boreholes, has until now been less thoroughly studied than have the first two options, but could turn out to be comparably attractive.

4. All Fissile Material. We recommend that the United States pursue new international arrangements to improve safeguards and physical security over all forms of plutonium and HEU worldwide. In particular, new cooperative efforts to improve security and accounting for all fissile materials in the former Soviet Union should be an urgent priority.

Because plutonium in spent fuel or glass logs incorporating high-level wastes still entails a risk of weapons use, and because the barrier to such use diminishes with time as the radioactivity decays, consideration of further steps to reduce the long-term proliferation risks of such materials is required, regardless of what option is chosen for disposition of weapons plutonium. This global effort should include continued consideration of more proliferation-resistant nuclear fuel cycles, including concepts that might offer a long-term option for nearly complete elimination of the world’s plutonium stocks.

On September 27, 1993, the Clinton administration announced a non-proliferation initiative that included some first steps in the directions recommended above, among them a proposal for a global convention banning production of fissile materials for weapons; a voluntary offer to put U.S. excess fissile materials under International Atomic Energy Agency (IAEA) safeguards; and a recognition that plutonium disposition is an important non-proliferation problem requiring renewed interagency, and ultimately international, attention. This is a much needed and timely start; more, however, remains to be done.

The steps we recommend are designed to meet three key security objectives:

1. to minimize the risk that either weapons or fissile materials could be obtained by unauthorized parties;

2. to minimize the risk that weapons or fissile materials could be reintroduced into the arsenals from which they came, thereby halting or reversing the arms reduction process; and

3. to strengthen the national and international arms control mechanisms and incentives designed to ensure continued arms reductions and prevent the spread of nuclear weapons.

Other key criteria include protecting worker and public health and the environment; being acceptable to the public and the institutions whose approval is needed; and, to the extent consistent with other criteria, minimizing costs and delays.

We note that the expenditures implied by all our recommendations combined would total at most several billion dollars, spread over a period of a decade or decades. Since the primary objective is the reduction of major security risks, these expenditures should be considered in the context of the far larger sums being spent every year to provide national and international security. Thus, although the costs of alternate approaches are important and are discussed in the report, cost is not the primary criterion in choosing among competing options. Moreover, exploiting the energy value of plutonium should not be a central criterion for decision making, both because the cost of fabricating and safeguarding plutonium fuels makes them currently uncompetitive with cheap and widely available low-enriched uranium fuels, and because whatever economic value this plutonium might represent now or in the future is small by comparison to the security stakes.

The problem of management and disposition of excess weapons plutonium must be considered in the context of the large world stocks of fissile materials. While all but a small fraction of the world’s HEU is in military use, civilian stocks of plutonium are several times larger than military stocks and are growing much faster, by some 60 to 70 tons each year. Most of these civilian stocks, however, are in the form of radioactive spent fuel from the world’s power reactors, from which the plutonium is difficult to extract. The difficulty of extracting this plutonium declines substantially as the radioactivity of the fuel decays over the decades after it leaves the reactor. Roughly 130 tons of plutonium have been separated from spent fuel for reuse as reactor fuel, of which some 80 to 90 tons remains in storage in separated form.

Plutonium customarily used in nuclear weapons (weapons-grade plutonium) and plutonium separated from spent reactor fuel (reactor-grade plutonium) have different isotopic compositions. Plutonium of virtually any isotopic composition, however, can be used to make nuclear weapons. Using reactor-grade rather than weapons-grade plutonium would present some complications. But even with relatively simple designs such as that used in the Nagasaki weapon—which are within the capabilities of many nations and possibly some subnational groups—nuclear explosives could be constructed that would be assured of having yields of at least 1 or 2 kilotons. Using more sophisticated designs, reactor-grade plutonium could be used for weapons having considerably higher minimum yields. Thus, the difference in proliferation risk posed by separated weapons-grade plutonium and separated reactor-grade plutonium is small in comparison to the difference between separated plutonium of any grade and unseparated material in spent fuel.

While plutonium and HEU can both be used to make nuclear weapons, there are two important differences between them. The first is that HEU can be diluted with other, more abundant,

naturally occurring isotopes of uranium to make low-enriched uranium (LEU), which cannot sustain the fast-neutron chain reaction needed for a nuclear explosion. LEU is the fuel for most of the world’s nuclear power reactors. In contrast, plutonium cannot be diluted with other isotopes of plutonium to make it unusable for weapons. “Re-enriching” LEU to the enrichment needed for weapons requires complex enrichment technology to which most potential proliferators do not have access, while separating plutonium from other elements with which it might be mixed in fresh reactor fuel requires only straightforward chemical processing. Thus, the management of plutonium in any form requires greater security than does the management of LEU.

Second, as noted earlier, in the current nuclear fuel market, the use of plutonium fuels is generally more expensive than the use of widely available LEU fuels—even if the plutonium itself is “free”—because of the high fabrication costs resulting from plutonium’s radiological toxicity and from the security precautions required when handling it. As a result, while most of the world’s roughly 400 nuclear reactors could in principle burn plutonium in fuel containing a mixture of uranium and plutonium (mixed-oxide or MOX fuel), few—and none in the United States—are currently licensed to do so.

The United States has agreed to buy 500 tons of surplus Russian HEU, blended to LEU, for $11.9 billion over the next 20 years, provided certain conditions are met. The United States will later resell the material to fulfill the demand for nuclear fuel on the domestic and world markets. While the purchase of Russian plutonium could, similarly, be justified on security grounds, both the security aspects and the economics of using plutonium as reactor fuel would be less attractive than in the case of LEU.

Because of the more difficult technical and policy issues involved, this report focuses primarily on the disposition of plutonium rather than HEU.

The management and disposition of plutonium from dismantled nuclear weapons will take place within a complex international context that includes the arms reduction and nonproliferation regimes of which this problem is an element, the continuing crisis in the former Soviet Union, worldwide plans for civilian nuclear energy (particularly the use of separated plutonium), and existing approaches to safeguards and security for nuclear materials.

Recent nuclear arms reduction agreements and pledges, along with national decisions concerning what stocks of plutonium are to be declared “excess,” will largely set the parameters of how much plutonium will require disposition and when it will become available. The reductions agreements entail a complex and uneven schedule of reductions in deployed launchers between now and 2003. As yet, no agreement exists to govern the dismantlement of the surplus nuclear weapons, or the modes of storage and eventual disposition of the fissile materials, although discussions of some aspects of the problem are under way. Mutually agreed, monitored provisions for the disposition of fissile materials could help enhance political support for implementation of START II and for agreement on deeper reductions.

The current crisis in the former Soviet Union creates a variety of risks with respect to the management and disposition of nuclear weapons and fissile materials. We categorize these as dangers of:

• “breakup,” meaning the emergence of multiple nuclear-armed states where previously there was only one;

• “breakdown,” meaning erosion of government control over nuclear weapons and materials within a particular state; and

• “breakout,” meaning repudiation of arms reduction agreements and pledges, and reconstruction of a larger nuclear arsenal.

Breakup is the most immediate threat, mainly because of uncertainty over whether Ukraine will carry out its denuclearization pledges. Security concerns may well be the driving factors in Ukraine’s ultimate decision, but that decision could be affected by measures that ensure that weapons and fissile materials transferred to Russia will not be reused for military purposes, and that provide compensation for these materials.

Breakdown of the elaborate system of control of nuclear weapons and fissile materials in the former Soviet Union remains a possibility, despite Russian efforts to maintain the former Soviet systems for this purpose. The thefts of conventional weapons and nuclear materials other than plutonium and HEU that have already occurred are disturbing. Enhanced assistance in improving security and accounting for fissile materials in the former Soviet Union is a potentially high-leverage area deserving urgent attention. The broad regime of accounting we recommend could provide an important basis for additional steps to improve security of these materials.

Breakout seems unlikely in the near term. The significant nuclear arsenals that each side will retain under START II will further reduce any motivation that a future Russian government might have for taking such a step. Ratification and implementation of START I and START II are not yet assured, however. The steps that we outline would reduce the potential for breakout, and provide a foundation for deeper reductions and for the inclusion of additional parties in the future.

The foundation of the nuclear nonproliferation regime is the Non-Proliferation Treaty (NPT), which is up for extension in 1995. Agreements for secure, safeguarded management and disposition of fissile materials from surplus nuclear weapons could help make clear that the nuclear powers are fulfilling their disarmament obligations under Article VI of the NPT. Moreover, acceptance by the major nuclear powers of safeguards and constraints on substantial portions of their nuclear programs would help to reduce the inherently discriminatory nature of the nonproliferation regime. These steps, while probably not dissuading all nations that might be attempting to acquire nuclear weapons, would help build global political support for indefinite extension of the NPT and strengthening the regime, which are major U.S. policy goals.

International efforts to reduce the proliferation risks posed by the existence of civilian plutonium and enriched uranium rest on safeguards, which are national and international measures designed to detect diversion of materials and enable a timely response, and security, which consists of (currently national) measures designed to prevent theft of materials through the use of barriers, guards, and the like. Standards for both vary widely. Those applied to civilian materials, even separated plutonium and HEU, are less stringent than those applied to nuclear weapons and fissile material in military stocks. Varying and lower standards may be justified in the case of spent fuel for the first decades outside the reactor, when its high radioactivity makes it difficult to steal or divert, but they are not justified in the case of separated civilian plutonium or HEU. New steps toward improved and consistent international standards should be pursued.

Choices regarding the fissile materials from dismantled weapons may also affect and be affected by civilian nuclear power programs, a topic that depends on economic, political, and technical factors outside the scope of this study. In some countries, nuclear power programs already include the use of plutonium in the fuel loaded into reactors. But the amount of weapons plutonium likely to be surplus is small on the scale of global nuclear power use—the equivalent of only a few months of fuel for existing reactors—and it is not essential to the future of civilian nuclear power. There is thus no reason that disposition of this weapons plutonium should drive decisions on the broader questions surrounding the future of nuclear power.

The production of tritium was not part of our charge, and we have not examined alternatives for this purpose in detail. We believe, however, that there is no essential reason why plutonium disposition and tritium production need be linked, and there appear to be good arguments why they should not be. Technically, the scale of the plutonium disposition task is very much larger than any tritium production requirement. From a policy perspective, producing weapons materials in the same facility that was destroying other weapons materials would raise political and safeguards issues.

We recommend a broad transparency regime for nuclear weapons and fissile materials, as outlined above. This regime could be approached step-by-step, with each step adding to security while posing little risk. The regime we envision would include a variety of measures applying to each phase of the life cycle of military fissile materials: production and separation of the materials; fabrication of fissile material weapons components; assembly, deployment, retirement, and disassembly of nuclear weapons; and storage and eventual disposition of fissile materials. These measures should be mutually reinforcing, to build confidence that the information exchanged is accurate and that the goals of the regime are being met.

There is likely to be some resistance to a regime of full accounting and monitoring of total weapons and fissile material stocks and facilities, but such a regime meets objectives shared by the United States and Russia (and, for that matter, by many other countries). Moreover, extensive data exchanges and verification measures have already been agreed for deployed strategic nuclear forces and other military systems.

Declarations of total stocks of weapons and fissile materials, with their locations, coupled with exchanges of operating records and inspections of material production sites, would reduce the large uncertainty in present estimates of these stocks. Fissile material production facilities and their operating records can be examined to confirm consistency with reported production figures, and stocks of fissile materials and weapons at declared sites can be confirmed through routine and occasional challenge inspections. The commitment of the Russian and U.S. governments to such declarations and the progressive opening of Russian society should make it less likely that a stockpile or production facility of any significant size could be hidden.

Dismantlement should also be monitored. The United States is dismantling its nuclear weapons at a rate of somewhat less than 2,000 per year, with a goal of increasing that rate to 2,000—the maximum rate permitted by available facilities; personnel; and environment, safety, and health (ES& H) considerations. The plutonium components (“pits”) are being placed intact into

containers and put in intermediate storage at the Pantex disassembly site near Amarillo, Texas. The HEU components are being shipped to the Y-12 plant at Oak Ridge, Tennessee, for storage and eventual use as naval or civilian reactor fuel. Russian spokesmen have declared that Russia is dismantling nuclear weapons at four sites, at a rate comparable to the U.S. rate, and is storing the materials at several existing sites.

Neither the United States nor Russia plans to monitor the other’s dismantlement, although limited Ukrainian monitoring is reported to be in place in Russia. Means exist or could be developed to monitor dismantlement without undue interference or costs, while protecting sensitive information. As with other parts of the regime, some declassification would be necessary to permit effective monitoring. The basic approach would be a variant of the perimeter-portal monitoring system now in place to verify that missiles banned by the Intermediate-Range Nuclear Forces treaty are not being produced; war-heads entering and leaving the facility would be counted, and amounts of fissile material measured. Such monitoring could be applied without undue interference with necessary maintenance and modification of the remaining military stockpile.

A cutoff of production of weapons materials would require monitoring of enrichment and reprocessing facilities. Still greater confidence could be achieved if all fuel cycle facilities were monitored. These tasks could be carried out by bilateral or international monitors (or both), using means that have met international acceptance in nonproliferation verification. Continued production of HEU for naval reactors and tritium for nuclear stockpile maintenance would introduce some complications, but these could readily be addressed through careful design of the agreement and the monitoring system.

The United States is no longer producing plutonium or HEU for weapons. Russia has also ceased production of HEU for weapons, but is still operating plutonium production reactors and separating the resulting weapons-grade plutonium. The Russian government asserts that these reactors provide necessary heat and power to surrounding areas, and that the fuel must be reprocessed for safety reasons. The United States has begun discussions with Russia about assistance in converting these reactors so that separated weapons plutonium is not generated, or in providing alternate power sources, but these discussions remain embryonic.

The security goals outlined above would be best served if the standards set by this regime for managing U.S. and Russian excess weapons and fissile materials were extended worldwide. In particular, new agreements should be pursued to:

1. create consistent, stringent international standards of accounting and security for fissile materials;

2. end all production of fissile materials for nuclear weapons, worldwide;

3. create an international system of declarations and inspections covering declared nuclear weapons arsenals, including reserves, and fissile material stocks (complementing the declarations and inspections already required of non-nuclear-weapon-state parties to the Non-Proliferation Treaty); and

4. create an international safeguarded storage regime under which all civilian fissile materials not in immediate use would be placed in agreed safeguarded storage sites, with agreed levels of physical security.

The IAEA secretariat and organizations in several countries are now working on concepts for such universal reporting and safeguarding of civilian fissile materials. These steps, and others that we recommend, would require increased resources for the IAEA, as well as organizational improvements. In some cases resources could be provided specifically for a new task. But the agency also urgently needs more resources overall.

It will be necessary to provide secure intermediate storage of surplus weapons plutonium for decades, since long-term disposition will take years to start and possibly decades to complete. In both the United States and Russia, fissile materials from dismantled weapons are currently stored in the form of weapons components, some at the dismantlement site and some elsewhere. Neither country has yet decided how much will be held in reserve. No monitoring or transparency measures relating to storage of these fissile materials are yet in place, although the Clinton administration has announced that U.S. excess fissile materials will be placed under international safeguards, and Russia has expressed willingness to do the same. Russia and the United States also have tens of tons of weapons-grade plutonium not incorporated in weapons that are stored in various forms at several sites in their weapons complexes.

In the United States, plutonium from weapons is being stored temporarily in simple “igloos” at Pantex, the dismantlement site. This arrangement provides high security and generally adequate standards of protection for environment, safety, and health. Given the stability of both the pits and the facilities at the site, there is no technical or economic reason why this arrangement could not be continued for a considerable time, but the public and the authorities in the area surrounding the site have been assured that interim storage there will not be extended beyond a decade. To meet that pledge, and to provide improved storage for plutonium in other forms now stored at several widely dispersed sites, the Department of Energy proposes to invest in a new, consolidated facility for long-term storage at a site to be selected. No full analysis of the advantages and disadvantages of this approach compared to upgrading existing storage facilities has been completed. We therefore do not offer a recommendation, though we recognize the safeguards and security advantages that a new consolidated facility might offer.

Less is known about Russian storage arrangements. Russia has requested, and the United States has agreed to provide, assistance in constructing a storage facility for excess fissile materials from weapons. We support construction of a facility designed to consolidate all these excess weapons materials, as this would facilitate security and international monitoring.

There is considerable debate concerning the optimum physical form in which to store plutonium. We recommend that, for the time being, plutonium continue to be stored in the form of intact weapons components. Decades of experience have demonstrated that pits are relatively

safe and stable, and storage in this form would postpone the costs and ES&H issues of conversion to other forms. Although the design of pits is sensitive, international monitors could externally assay the amount of plutonium in a canister containing a pit without, in most cases, revealing sensitive design information. Intact pits can more easily be reused for weapons by the state that produced them than plutonium in other forms, but they probably do not pose substantially greater proliferation risks than storage as deformed pits or metal ingots. Deformation of pits and perhaps other steps to reduce the rearmament risk should be given serious consideration, and should be undertaken if they can be accomplished at relatively low cost and ES&H risk.

One cannot be confident, however, that plutonium in pits can be stored without degradation for more than a few decades. When a definite decision regarding long-term disposition has been made, the pits should be converted into the forms required for that disposition option, under agreed safeguards and security.

The following measures constitute a regime for intermediate storage of surplus fissile materials that serves the objectives noted earlier with minimum disruption to the process of dismantlement and storage:

1. Commitment to Non-Weapons Use. The United States and Russia should commit a large fraction of the fissile materials from dismantled weapons to non-weapons use. They should agree on the specific amounts.

2. Safeguarded Storage and Disposition. The preceding commitment should be verified by monitoring of the present and future sites where fissile materials are stored, and continued monitoring of the material after it leaves these sites for long-term disposition.

3. IAEA Involvement. Although such monitoring might begin bilaterally, the IAEA should be brought into the process expeditiously, in an expansion and strengthening of its non-proliferation role. The IAEA would monitor the amount of material in the storage site and safeguard any material removed from the site to ensure its use for peaceful purposes. Such safeguards would be an extension of the existing safeguards system. Bilateral monitoring would probably continue as well.

Financial or other incentives could be provided to Russia for putting the material into storage. Management, control, or outright ownership of the stores and the material in them might be transferred to other parties, such as an international consortium formed for that purpose. The material might even be physically relocated to some other country, possibly in return for cash, as in the case of the HEU deal. Such incentives would not obviate the need for, and are secondary to, prompt agreement on a storage regime along the lines recommended here.

The technical options for long-term disposition of excess weapons plutonium can be divided into three categories:

• indefinite storage, in which the storage arrangements outlined in the previous section would be extended indefinitely;

• minimized accessibility, in which physical, chemical, or radiological barriers would be created to reduce the plutonium’s accessibility for use in weapons (either by potential proliferators or by the state from whose weapons it came), for example, by irradiating the plutonium in reactors or mixing it with high-level wastes; and

• elimination, in which the plutonium would be made essentially completely inaccessible, for example, by burning it in reactors so completely that only a few grams would remain in a truckload of spent fuel, or by launching it into deep space.

In both the “minimized accessibility” and the “elimination” categories, some of the options use the plutonium to generate electricity, while others dispose of the plutonium without using its energy content. Both classes of options would involve net economic costs. The electricity generation options would produce revenues, but the costs of using plutonium to produce this electricity would be higher than the costs of generating it using enriched uranium. The current Russian government nonetheless sees weapons plutonium as a valuable asset and therefore strongly prefers options that use the plutonium.

Risks of Storage. Although intermediate storage is an inevitable step preceding all disposition options, it should not be extended longer than necessary. Maintaining this material in a readily weapons-usable form over the long term would send negative political signals for non-proliferation and arms reduction, and the security offered by indefinite storage against the risks of breakout and theft is entirely dependent on the durability of the political arrangements. Indeed, one of the key criteria by which disposition options should be judged is the speed with which they can be accomplished, and thus how rapidly they curtail these risks of storage.

Risks of Handling—The “Stored Weapons Standard.” Although options in the “minimized accessibility” and “elimination” classes decrease the long-term accessibility of the material for weapons use, they could increase the short-term risks of theft or diversion because of the required processing and transport steps. In order to ensure that the overall process reduces net security risks, an agreed and stringent standard of security and accounting must be maintained throughout the disposition process, approximating as closely as practicable the security and accounting applied to intact nuclear weapons. We call this the “stored weapons standard.” These risks of handling are a second key criterion for judging disposition options.

Risks of Recover—The “Spent Fuel Standard.” A third key security criterion for judging disposition options is the risk of recovery of the plutonium after disposition. We believe that options for the long-term disposition of weapons plutonium should seek to meet a “spent fuel standard”—that is, to make this plutonium roughly as inaccessible for weapons use as the much larger and growing quantity of plutonium that exists in spent fuel from commercial reactors. Options that left the plutonium more accessible than these existing stocks would mean that this

material would continue to pose a unique safeguards problem indefinitely. Conversely, the costs, complexities, risks, and delays of going beyond the spent fuel standard to eliminate the excess weapons plutonium completely, or nearly so, would not be justified unless the same approach were to be taken with the global stock of civilian plutonium. Over the long term, however, steps beyond the spent fuel standard will be necessary—for both the weapons plutonium and the larger civilian stock—as described below.

In addition, policymakers will have to take into account the political impact that the use of excess weapons plutonium in reactors, or the disposal of that plutonium, would have on nuclear fuel cycle debates abroad. Whatever choice it makes, the United States will have to explain how that choice fits into the broader context of its nonproliferation and fuel cycle policies.

The best means of plutonium disposition may well differ in the United States and Russia, given that the two countries have different economies, reactor and waste infrastructures, and plutonium fuel policies, and given that very different safeguards and security risks currently pertain.

As noted above, there are two options that hold especially strong promise of being able to meet the criteria just outlined: the use of plutonium as fuel in existing or modified reactors without reprocessing, and vitrification together with high-level wastes. A third option, burial in deep boreholes, might prove on further study to be on a par with the first two. We now describe each of these options in turn.

Excess weapons plutonium could be used as fuel in reactors, transforming it into intensely radioactive spent fuel similar in most respects to the spent fuel produced in commercial reactors today. This use could probably begin within approximately 10 years (paced by obtaining the necessary fuel fabrication capability and the needed approvals and licenses) and be completed within 20 to 40 years thereafter (paced by the number of reactors used, the fraction of the reactor core using plutonium fuel, the percentage of plutonium that this fuel contains, and the amount of time that the fuel remains in the reactor). Examples include:

• U.S. Light-Water Reactors. The predominant commercial reactors in the world today are light-water reactors (LWRs). Without major modifications, typical LWRs could burn a fuel consisting of mixed oxides of plutonium and uranium (MOX) in one-third of their reactor cores. Four existing LWRs in the United States (three operational at Palo Verde in Arizona, and one 75 percent complete in Washington State) were designed to use MOX in 100 percent of their reactor cores; a single such reactor, using fuel containing somewhat more plutonium than would be used if energy production alone were the aim, could transform 50 tons of weapons plutonium into spent fuel in 30 years. Alternatively, other operating or partly completed reactors could also be modified to use full MOX cores, or a new full-MOX reactor might be built on a government site, with costs partly offset by later sales of electricity.

  Although the United States has no operating MOX fuel fabrication capability, there is an unfinished facility at the Hanford site that could be completed and modified for this purpose; alternatively, a new MOX facility could be built in roughly a decade, at significantly higher cost.

This option is technically demonstrated, as LWRs in several countries are burning MOX fuels today. Environmental, health, and safety risks can be minimized with the application of money and good management, although some of the specifics of how best to do so require further study. Use of MOX fuels, however, would be controversial in the United States, where such fuels are not now used, and gaining licenses and public approval could raise difficulties. The subsidy required to transform 50 tons of plutonium into spent fuel in this way (compared to the cost of producing the same electricity by the means with which it would otherwise be produced) would probably fall in the range from a few hundred million to a few billion dollars, depending on assumptions and on the specific approach chosen.

• Russian Light-Water Reactors. Similarly, Russian plutonium could be used as MOX in Russian VVER-1000 reactors (the only existing reactors in Russia likely to be safe enough and long-lived enough for this mission). VVER-1000s that are not yet operational, but that the Russian government plans to complete for electricity production, could be modified to handle full MOX cores, or such modifications could be incorporated in operating reactors during the shutdowns for safety improvements that are now planned. Because of the current political and social upheaval in Russia, safeguards and security risks would be substantial. The current Russian government ’s preference for storing plutonium until it can be used in the next generation of Russian liquid-metal fast reactors is not attractive because of the indefinite time before disposition could begin, the security liabilities of prolonged storage, and the high cost of these reactors.

• CANDUs. Existing Canadian deuterium-uranium (CANDU) reactors are a technically attractive possibility for this mission, because the reactor design allows them inherently to handle full-MOX cores, with less change from the usual physics of the reactor than in the case of LWRs. The cost of this option is difficult to estimate, as no one has yet attempted to fabricate MOX fuel for CANDU reactors on any significant scale. We do not know whether the opportunity for Canada to participate in an important disarmament process, combined with possible U.S. subsidies for the project, would be attractive enough to cause that country to reverse its long-standing policy against the use of fuels other than natural uranium in its power reactors.

• Substitution for Civilian Plutonium. Utilities in Europe and Japan currently plan to use more than 100 tons of reactor-grade plutonium in MOX fuels over the next decade. If excess weapons plutonium from Russia or the United States were substituted for this material—with an associated delay in separation of plutonium from civilian spent fuel, so that additional excess stocks of civilian plutonium did not build up as a result—disposition of 50 or even 100 tons of plutonium could be accomplished relatively rapidly (since the facilities required are already built and licensed, or scheduled to be) and with comparatively small net additional safeguards risks (since after the initial transport, all the facilities handling plutonium would have done so in any case). However, the agreements required to implement this option would be complex and probably difficult to reach. Substantial changes in a variety of existing contracts and programs would have to be made, and transport of weapons plutonium to these countries would be controversial.

• New Reactors for the Plutonium Mission. Given the high costs and long times required for the construction of new reactors, building such reactors for the mission of transforming weapons plutonium into spent fuel would be justifiable only if problems of licensing and public accep-

tance made currently operating or partly completed reactors unavailable (and only, of course, if the reactor-MOX option were deemed preferable to the vitrification and deep-borehole approaches). If that proves to be the case, the new reactors should be built on a government-owned site and should be of sufficiently well-proven design so as not to create additional technical and licensing uncertainties. Reactors we have examined of more advanced design do not offer sufficient advantages for this mission to offset the extra costs and delays that their use would entail. In particular, the use of advanced reactors and fuels to achieve high plutonium consumption without reprocessing is not worthwhile, because the consumption fractions that can be achieved —between 50 and 80 percent—are not sufficient to greatly alter the security risks posed by the material remaining in the spent fuel. Development of advanced reactors and fuel types is of interest for the future of nuclear electricity generation, including the minimization of safety and security risks, but the timing and scope of such development need not and should not be governed by the current weapons plutonium problem.

An alternative means of creating similar radioactive and chemical barriers to weapons use of this material would be to mix it with radioactive high-level waste (HLW) left from the separation of plutonium from weapons and other defense activities. Under current plans, HLW will be mixed with molten glass (vitrified) to produce large glass logs. These logs, like spent reactor fuel, will be stored for an interim period and then placed in a geologic repository. The logs would pose radiological barriers to handling and processing similar to those of spent LWR fuel a few decades old. Incorporating plutonium into these logs appears feasible, although technical questions remain. These technical issues are more substantial than those facing the MOX options, but licensing and public approval appear easier to obtain in the vitrification case, at least in the United States. Vitrification raises fewer security risks in handling than the MOX option, because the process of mixing plutonium with HLW would be easier to safeguard than the more complex process of fabricating MOX. This might be of particular importance in the current Russian context. Russian vitrification efforts have so far focused on a phosphate glass that is less appropriate for this mission than the borosilicate glass used in the United States and elsewhere because it is less durable and offers less protection against the possibility of an unplanned nuclear chain reaction once plutonium is embedded in it. New technologies for comparatively small melters could be transferred to Russia for this purpose. So far, however, the Russian officials responsible for these issues have rejected disposal options such as vitrification.

Disposal in deep boreholes has been examined in several countries as an approach to spent fuel and HLW management, and is still being examined in Sweden. Because of the very great depth of the holes, there are good reasons to believe that the materials emplaced would remain isolated from the environment for periods comparable to or possibly longer than those expected for the geologic repository case, but significant uncertainties must be resolved. Plutonium in such boreholes would be extremely inaccessible to potential proliferators, but would be recoverable by the state in control of the borehole site. The method would be relatively inexpensive to implement, but developing

sufficient confidence to permit licensing could be costly and time-consuming; the United States has expended decades and billions of dollars in preparation for such licensing in the case of geological repositories for spent fuel and HLW.

All three of these options have the potential to be satisfactory next steps beyond interim storage in the disposition of excess weapons plutonium. None of them, however, could be confidently selected until currently open questions, described in Chapter 6 of this report, are answered.

A variety of other reactors have been proposed for this mission, such as high-temperature gas-cooled reactors, fast-neutron reactors, or various existing research or plutonium production reactors. Existing reactors other than the LWRs and CANDUs described above should be rejected on grounds of the uncertain availability and safety of those reactors with sufficient capacity. The advanced reactors, as noted above, are not competitive for this mission because of the cost and delay of their development, licensing, and construction.

A variety of exotic disposal options have also been proposed, including sub-seabed disposal, detonation in underground nuclear explosions, launching into deep space, and dilution in the ocean, among others. This report rejects all of these on grounds of retrievability, cost, delay, environmental concerns, or conflict with existing policies and international agreements.

Long-term steps will be needed to reduce the proliferation risks posed by the entire global stock of plutonium, particularly as the radioactivity of spent fuel decays. Options for reducing these risks could include placement of spent fuel in geologic repositories, or pursuit of fission options that would burn existing plutonium stocks nearly completely. A variety of reprocessing-oriented reactor options have been proposed for this mission, ranging from the use of standard LWRs to challenging concepts such as accelerator-based conversion. The costs of these approaches would be in the tens or hundreds of billions of dollars, and the time scales would be many decades or centuries, depending on the choice of options. These technologies can only be realistically considered in the broader context of managing the future of nuclear power to provide energy while minimizing the risk of nuclear proliferation, an important task that is beyond the scope of this committee. To further refine these concepts, research on fission options for near-total elimination of plutonium should continue at the conceptual level.

Although all the plausible disposition options will take many years to implement, it is important to begin now to build consensus on a road map for decision. Such a road map would provide guidelines for the necessary national and international debate to come, focus further efforts on those options most likely to minimize future risks, and provide plausible end points for the process that the near-term steps will set in motion. Research and development should be undertaken immediately to resolve the outstanding uncertainties facing each of the options.

The institutional and political issues involved in managing weapons dismantlement, intermediate storage of fissile materials, and long-term disposition may be more complex and difficult to resolve than the technical ones. Because disposition options will require decades to carry out, it is critical that decisions throughout be made in a way that can muster a sustainable consensus. The entire process must be carefully managed to provide adequate safeguards, security, and transparency; to obtain public and institutional approval, including licenses; and to allow adequate participation in the decision making by all affected parties, including the U.S. and Russian publics and the international community. Adequate information must be made available to give substance to the public’s participation.

These issues cover a broad institutional and technical spectrum. Establishing fully developed arrangements for managing these tasks will require an unusually demanding integration of policy under conditions of dispersed authority and intense political sensitivity. In the United States, jurisdiction over fissile material and fabricated weapons is divided between the Department of Energy (DOE) and the Department of Defense (DOD) in different phases of the deployment cycle. Each department has many subordinate divisions involved. Related diplomacy is handled by the State Department and the Arms Control and Disarmament Agency, with input from DOE and DOD. Numerous other agencies perform supporting functions. The relevant installations are authorized and financed by Congress, regulated by independent agencies and commissions, constrained by state laws, and increasingly affected by public opinion in their surrounding communities. Policy debates too often focus on specific options, such as particular reactor types, rather than the comprehensive view required to make choices for this complex problem. The consequences of this fragmentation are illustrated in a related area by the fact that technical assessment of the U.S. high-level waste repository at Yucca Mountain is incomplete after two decades of work and billions of dollars of expenditure, and final licensing is not projected for another two decades. These challenges to comprehensive policymaking are at least as great in Russia, where they must be surmounted in the midst of continuing political and economic upheaval.

None of the governments involved have previously faced the problem of handling excess plutonium in the quantities now contemplated, and none appear to have developed policies and procedures likely to be adequate to the task. Yet decisions are urgent, since without new approaches even the near-term tasks of dismantlement and storage are not likely to meet all of the required security criteria.

In these areas, the United States bears a special burden of policy leadership. If demanding technical assessments are to be completed, if consensus is to be forged, and if implementation is to be accomplished in reasonable time, major advances in the formulation and integration of policy and in institutional coordination will be needed. The president should establish a more systematic process of interagency coordination to deal with the areas addressed in this report, with sustained top-level leadership. The new interagency examination of plutonium disposition options envisioned in President Clinton ’s September 27, 1993, nonproliferation initiative is a first step in that direction, but much more remains to be done.

• The president should establish a more systematic process of interagency coordination to deal with the areas addressed in this report, with sustained top-level leadership.

• The United States and Russia should make formal commitments that specific quantities of fissile material from dismantled weapons (representing a very large fraction of those materials) will be declared excess and committed to non-weapons use or disposal. Storage and disposition of these materials should be subject to agreed standards of accountability, transparency, and security. The standards for accountability and security should approximate as closely as possible the stringent standards applied to stored nuclear weapons.

• The United States should negotiate with Russia to create, through a step-by-step process, a broad regime under which each side ’s stocks of nuclear weapons and fissile materials would be declared and monitored, and the size of both stocks would be verifiably reduced over time in line with current reductions in deployed delivery systems. This regime would include, in addition to the fissile material steps mentioned in the previous recommendation:

  1. a system of mutual declarations of total inventories of nuclear weapons and of fissile materials in civilian and military inventories;

  2. measures designed to increase confidence in the accuracy of the declarations, and the transparency of each side’s nuclear weapons production complexes, including physical access to production facilities and production records for fissile materials;

  3. a monitored cutoff of production of HEU and plutonium for weapons —if necessary, the United States should be willing to provide limited funding to assist Russia in the measures necessary to cut off plutonium production; and

  4. an agreement providing for perimeter portal monitoring of dismantlement facilities, counting warheads entering these facilities, and assaying the fissile material that leaves. If the net subtractions from each side’s stockpile are to be confirmed, some monitoring of warhead assembly will be required as well.

• Information concerning the total stockpiles of weapons and fissile materials, and those weapons characteristics necessary for external monitoring, should be declassified as part of this transparency regime. Appropriate reviews to prepare for such declassification should be initiated promptly.

• Russia and the United States should dismantle their retired warheads as expeditiously as is practical, consistent with protection for the environment, safety, and health, and cost-effectiveness.

• The United States and Russia should place plutonium excess to military needs in safeguarded storage as soon as practical.

• Stored excess fissile materials committed to non-weapons use or disposal by the United States and Russia should be placed under international safeguards (possibly combined with bilateral monitoring). In the interest of speed, monitoring of storage could initially be a bilateral U.S.-Russian effort, but the IAEA should be brought into the process rapidly.

• Plutonium from dismantled weapons should continue to be stored as intact pits for now. Deformation of these pits and perhaps other steps to reduce the rearmament risk should be given serious consideration, and should be undertaken if they can be accomplished at relatively low cost and risk to the environment, safety, and health.

• Pits should be stored in sealed containers, with monitors permitted to assay the containers externally without observing the pits’ dimensions, to provide adequate safeguards without compromising sensitive weapons design information.

• Once definite disposition options have been chosen, the plutonium should be converted expeditiously to whatever form is required as part of the disposition process.

• Financial or other incentives might be provided to encourage Russia to place the maximum amount of material into monitored storage. With the condition that these not be an open-ended commitment or provide any idncentive for continued production of separated plutonium, such incentives would be desirable and should continue to be explored.

• The United States should continue providing assistance for a Russian fissile material storage facility, which should be designed to consolidate all excess weapons materials under appropriate standards of security and international monitoring.

• The safeguards budget of the IAEA should be substantially increased, and other steps should be taken to strengthen that organization ’s ability to carry out its critical responsibilities. One promising approach would be the creation of a voluntary fund, to which nations interested in improved safeguards would make contributions above and beyond their fixed allocations.

• Appropriate arrangements for intermediate storage are to a large extent decoupled from long-term disposition decisions and should be considered more urgent.

• It is important to begin now to build consensus on a road map for decisions concerning long-term disposition of excess weapons plutonium. Because disposition options will take decades to carry out, it is critical to develop options that can muster a sustainable consensus.

• Storage should not be extended indefinitely, because of (1) the negative impact that maintaining this material in forms readily accessible for weapons use would have on nonproliferation and arms reduction, (2) the risk of breakout, and (3) the risks of theft from the storage site. One of the key criteria by which disposition options should be judged is the speed with which they can be accomplished, and thus the degree to which they curtail the risks of prolonged storage.

• Disposition options beyond storage should be pursued only if they reduce overall security risks compared to leaving the material in storage, considering both the final form of the material and the risks of the various processes required to get to that state. In the current unsettled circumstances in Russia, this minimum criterion is a significant one.

• The United States and Russia should begin discussions with the aim of agreeing that whatever disposition options are chosen, an agreed, stringent standard of accounting, monitoring, and security will be maintained throughout the process—coming as close as practicable to meeting the standard of security and accounting applied to intact nuclear weapons.

• Disposition options should be designed to transform the weapons plutonium into a physical form that is at least as inaccessible for weapons use as the much larger and growing stock of plutonium that exists in spent fuel from commercial nuclear reactors. The costs, complexities, risks, and delays of going further than this “spent fuel standard” to eliminate the excess weapons plutonium completely or nearly so would not be justified unless the same approach were to be taken with the global stock of civilian plutonium.

• The two most promising alternatives for the purpose of meeting the spent fuel standard are:

1. the spent fuel option, which has several variants. The principal one is to use the plutonium as once-through fuel in existing commercial nuclear power reactors or their evolutionary variants. Candidates for this role are U.S. light-water reactors (LWRs), Russian LWRs, and Canadian deuterium-uranium (CANDU) reactors. The use of European and Japanese reactors already licensed for civilian plutonium should also be considered for Russian weapons plutonium.

2. the vitrification option, which would entail combining the plutonium with radioactive high-level wastes as these are melted into large glass logs. The plutonium would then be roughly as difficult to recover for weapons use as plutonium in spent fuel.

A third option, burial in deep boreholes, has until now been less thoroughly studied than alternatives 1 and 2, but could turn out to be comparably attractive.

• A coordinated program of research and development should be undertaken immediately to clarify and resolve the uncertainties we have identified regarding each of these three options. The aim should be to pave the way for a national discussion, with full public participation, in order to make a choice within a very few years.

• Applying the spent fuel standard narrows the options considerably:

1. Options that irradiate the weapons plutonium in reactors only briefly (“spiking”), leaving it far less radioactive than typical spent fuel, and with little change in its isotopic composition, should not be pursued except possibly as a preliminary step on the road toward the spent fuel option. (Even for that purpose, in those cases the committee has examined, the possible advantages of the spiking option over continued storage do not appear to be worth the substantial cost of such spiking approaches.)

2. Options that involve only a chemical barrier to reuse—such as vitrification of plutonium without HLW or other fission products —should not be pursued, except possibly as a first step toward adding radiological or physical barriers as well.

3. Advanced reactors should not be specifically developed or built for transforming weapons plutonium into spent fuel, because that aim can be achieved more rapidly, less expensively, and more surely by using existing or evolutionary reactor types.

4. Options that strive to destroy a large fraction of the plutonium without reprocessing and recycle, using existing or advanced reactors with nonfertile fuels, should not be pursued because such approaches cannot destroy enough of the plutonium to obviate the need for continuing safeguards, and the modest reduction in security risk that could be achieved is not worth the extra delay, cost, and uncertainty that the development of such approaches would entail.

• Production of tritium should not be a major criterion for choosing among disposition options.

• Institutional issues in managing plutonium disposition are complex and the process to resolve them must be carefully managed. The process must provide adequate safeguards, security, and transparency, as well as protection for the environment, safety, and health; obtain public and institutional approval, including licenses; and allow adequate participation in the decision making by all affected parties, including the U.S. and Russian publics and the international community. Adequate information must be made available to give substance to the public’s participation.

• Although we did not conduct a comprehensive examination of the proliferation risks of civilian nuclear fuel cycles, which would have gone beyond our charge, the risks posed by all forms of plutonium must be addressed.

• While the spent fuel standard is an appropriate goal for next steps, further steps should be taken to reduce the proliferation risks posed by 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. Options for near-total elimination of plutonium may have a role to play in this effort, and research on defining and exploring these options should be continued at a conceptual level. These options, however, can only realistically be considered in the broader context of the future of nuclear electricity generation, including the minimization of security and safety risks—the assessment of which is beyond the scope of this report. Studies of that broader context should

have as one important focus minimizing the risk of nuclear proliferation, and should consider nuclear systems as a whole, from the mining of uranium through to the disposal of waste; should consider feasible safeguarding methods as elements of development and design; and should take an international approach, realizing that other nations ’ approaches reflect their differing economic, political, technical, security, and geographic situations and perceptions.

• Urgent steps are needed to improve safeguards and security for all fissile materials in the former Soviet Union, including materials beyond those considered excess. We recommend a comprehensive approach at a significantly higher level of funding, with an emphasis on cooperation in addressing the most immediate risks. Western countries, including the United States, should press Russia and the other states of the former Soviet Union to take a number of steps urgently—within weeks or months, rather than years—and should be willing to provide necessary equipment and funds for these purposes. In particular, Western countries should press for, and offer assistance for:

  1. immediate installation of appropriate portal monitoring systems to detect any theft of fissile materials, and adequate armed guard forces at all sites where enough weapons-usable fissile material to make a nuclear weapon is stored;

  2. an urgent program of security inspections and improvements at all of these sites;

  3. improved economic conditions for personnel responsible for accounting and security of weapons and fissile materials, to reduce incentives for corruption and insider theft;

  4. improved national oversight of security and safeguards, with a strengthened basis in law (in Russia, this would involve strengthening the role of GOSATOMNADZOR, while in other former Soviet states it would involve strengthening or creating comparable organizations);

  5. consolidation of fissile material storage and handling where possible;

  6. conversion of research reactors to run on low-enriched uranium fuels, reducing the number of sites where weapons-grade fissile materials are used;

  7. greater Western participation and cooperation in safeguards and security, ideally at all fissile material sites, but—at a minimum—at all civilian sites; and

  8. regularized, as well as emergency, working-level cooperation in monitoring reports of alleged diversions.

• The steps we have outlined to improve safeguards and physical security for fissile materials in the United States and Russia should set a standard for a regime of improved management of such materials in civil use throughout the world. Negotiations should be pursued to:

  1. create a global cutoff of all unsafeguarded production of fissile materials;

  2. use the U.S.-Russian safeguarded storage regime recommended above as a base for a broad international storage and management regime for fissile materials, including registration and safeguards for all civilian separated plutonium and HEU;

  3. extend the U.S.-Russian declaratory regime mentioned above to a global regime of public declarations of stocks of fissile materials;

4. agree on higher standards of physical security for these materials, with an international organization given authority to inspect sites to monitor whether the standards are met; and

5. agree on coooperative international approaches to manage reprocessing and use of plutonium to avoid building up excess stock.