Management and Disposition of Excess Weapons Plutonium (1994) / Chapter Skim
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Chapter 6: Long-Term Disposition
Chapter 6: Long-Term Disposition
Pages 141-222
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From page 141... ...
· None of the options is sufficiently developed to be chosen as the preferred approach until outstanding questions are answered. This chapter offers not a final answer but a road map for arriving at one; it is intended to provide guidelines for the necessary national and international debate to come, to narrow the focus of attention to the subset of options most likely to minimize risks, and to provide plausible end points for the dismantlement and storage activities now under way.
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From page 142... ...
(This existing problem will itself change over time as the radioactivity decays, repositories or monitored retrievable storage sites become available, and approaches to safeguards and security and nuclear fuel cycles evolve.) Incurring substantial additional costs, complexities, risks, or delays in order to go further and eliminate the excess weapons plutonium completely or nearly so would not be justified
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From page 143... ...
Research on defining and exploring these options should be continued at the conceptual level. ' The spent fuel option, in which the weapons plutonium would actually be converted to spent fuel, should not be confused with the spent fuel standard: it is merely one means of meeting that standard.
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From page 144... ...
· 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.
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From page 145... ...
, for example, considers that materials no longer require safeguards if the remaining fissile material in them has been "consumed," or so diluted as to be "practically irrecoverable" for weapons use. Quantitative measures for termination of safeguards, which might provide one standard for judging when to consider fissile material "eliminated," have not yet been finalized.
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From page 146... ...
While the United States and other industrialized countries cannot dictate particular disposition options to Russia, they will have a significant influence on Russian decisions in a variety of ways ranging from simply setting an example on the one hand, to financial assistance, negotiated agreements to pursue particular approaches, or outright purchase of former Soviet weapons plutonium on the other. Other Forms of Military Plutonium.
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From page 147... ...
Each long-term disposition approach generates risks and opportunities with respect to theft, rearmament, and the arms reduction and nonproliferation regimes that depend on political and technical factors that will evolve over the long time periods involved in disposition. The committee judges the following security risks related to long-term disposition choices to be of greatest concern: Risks of Storage: Prolonged storage of excess weapons plutonium would mean a continuing risk of breakout, as well as of theft from the storage site.
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From page 148... ...
Conversely, as long as civilian plutonium exists and continues to accumulate, options that went further than the spent fuel standard and sought to eliminate the excess weapons plutonium entirely would provide little additional security, unless the same were done with the much larger amount of civilian plutonium. Thus, options for the next steps in long-term disposition of weapons plutonium shouldfocus on those in the "minimized accessibility" class.
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From page 149... ...
The political signals sent by the choice of particular disposition approaches might encourage the development and use of more proliferation-resistant nuclear fuel cycles; encourage the use of more proliferationprone nuclear fuel cycles; or serve to set a standard for improved safeguards and security for other fissile materials. Under the Carter administration, the United States decided not to reprocess civilian plutonium or pursue plutonium fuel cycles, and launched a major international effort to convince other countries that' such separated plutonium fuel cycles were uneconomical and posed significant proliferation risks.
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From page 152... ...
Whatever is done with excess weapons plutonium, moreover, will affect only a small portion of the world's current and future plutonium inventory. For either the use or the disposal options, if the United States wishes to maintain a policy of generally discouraging separated plutonium fuel cycles, or if it wishes to make support for such cycles contingent on stringent safeguards and security measures, it will need to make a clear statement of how its choice fits within that broader context.
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From page 153... ...
Of all long-term disposition options, indefinite storage would entail the highest risk of breakout and of proliferation by theft from the storage site. Prolonged storage of large quantities of excess fissile materials, particularly in the form of weapons components, would send the message that the nation storing these materials was maintaining the option to rebuild its Cold Warera nuclear arsenal.
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From page 154... ...
Although they might have some advantages for intermediate storage, they would do little to reduce the breakout threat or the political hazards of prolonged storage, and the risk of theft can be addressed by other means at existing or planned storage sites. Minimized Accessibility Options Reactor Options A wide range of reactors-existing, evolutionary, and advanced~ould use weapons plutonium in their fuel (for an illustration of the general steps involved, see Figure 6-2~.
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From page 155... ...
Thus, within the range of plutonium destruction achievable without reprocessing, the specific destruction fraction would have little impact on overall security risks, either those of the remaining plutonium in this spent fuel or those of the global stock of plutonium in spent fuel. Another possibility, discussed as a separate option in some studies, is to use much briefer irradiation of the weapons plutonium typically for only a few months to "spike" the plutonium with fission products, creating some radiation barrier to its use in weapons more rapidly (or with fewer reactors)
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From page 156... ...
Either existing reactors (possibly with modifications) or newly built reactors constructed for the purpose could process excess weapons plutonium into spent fuel.
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From page 157... ...
Commercial reactors of the types currently operating in the United States, known as light-water reactors, offer the technical possibility of transforming excess weapons plutonium into spent fuel within a few decades. Such a plutonium disposition campaign could probably begin within roughly a decade, paced by the need to provide a plutonium fuel fabrication capability (no such facility is currently operational in the United States)
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From page 158... ...
each, could transform 50 metric tons of excess weapons plutonium into spent fuel- substantially similar to what is already produced by these reactors in 150 to 250 reactor-years of operation.~° Put another way, 5-8 GWe of reactor capacity (out of a total U.S. LWR capacity of about 98 GWe)
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From page 159... ...
.~2 For example, the System-80 reactor could process 50 metric tons of excess weapons plutonium in 60 reactor-years using a 100 percent MOX core with a relatively low enrichment of 2.5 percent and an average burnup of 31,000 MWd/MTHM; increasing the initial enrichment to 6.8 percent (roughly the maximum likely to be possible without requiring changes to the reactor) would allow the job to be done in 30 reactor-years, even if the burnup were increased to 42,000 MWd/MTHM.
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From page 160... ...
The private entities might provide all or part of the initial investment, reducing the upfront capital cost to the government. Given the international implications of an excess weapons plutonium disposition program, and the need to set stringent standards for security and safeguards, a government role is required.
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From page 161... ...
reactors that utilities may be willing to provide to the government, either because they were never completed i4 this concept, known as the "Isaiah Project," is being put forward by a team consisting of Battelle, Science Applications International Corporation, and Newport News. (Briefing for NAS Panel on Reactor-Related Options for Disposition of Weapons Plutonium, May 7, 1993.)
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From page 162... ...
reactors. There are important open questions concerning the licensing process for the various plutonium disposition facilities.
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From page 163... ...
Problems of public approval and licensing could be lessened somewhat if both the plutonium fuel fabrication facilities and the reactors handling MOX fuels were on federal sites. This is the main argument for building new reactors at existing DOE sites, rather than relying on existing civilian reactors.
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From page 164... ...
As noted above, policymakers considering plutonium disposition options should be aware that the use of U.S. weapons plutonium in U.S.
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From page 165... ...
Processing weapons plutonium to spent fuel in existing U.S. LVVRs is technically feasible.
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From page 166... ...
regulatory environment; · assessing the acceptability of disposition of spent MOX fuel in geologic repositories; · examining ES&H issues throughout the process, particularly in pit processing and fuel fabrication; and · examining safeguards issues, particularly the ability to adequately safeguard MOX fuel fabrication facilities processing several tons of weapons-grade plutonium per year. Further investigation of several institutional issues is also needed: · licensing MOX fabrication facilities and reactors operating with plutonium fuels, including 100 percent MOX cores; · addressing likely political opposition to plutonium fabrication and use
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From page 167... ...
use of weapons plutonium in reactors on the use of separated plutonium fuels in other countries. RUSSIAN PLUTONIUM ~ RUSSIAN LWRs The major differences in using Russian LWRs to process Russian excess weapons plutonium include much higher security risks in the disposition process, because of the current economic and political upheavals in the former Soviet Union; much lower availability of funds to finance the process; a smaller existing infrastructure of safe reactors; and different economic conditions, plutonium fuel policies, and licensing procedures.
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From page 168... ...
But as noted above, U.S. or international financial assistance may well be required if long-term disposition of excess weapons plutonium in Russia is to be accomplished in the foreseeable future.
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From page 169... ...
The standards of safeguards, security, and ES&H that this plant was designed to meet or could practicably be modified to meet-are unknown. Alternatively, a new MOX fabrication facility dedicated to the excess weapons plutonium disposition mission could be constructed.
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From page 170... ...
There might also be some political impact in other countries whose civilian plutonium programs are controversial. Russia also has some 25 tons of separated civilian plutonium waiting to be fabricated into fuel; some Russian officials and European analysts have suggested that they should fabricate this material into fuel before beginning the use of weapons plutonium, since civilian plutonium builds up radioactivity that makes it difficult to handle more quickly.
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From page 171... ...
Summary. Processing weapons plutonium in Russian LWRs, operating and nearly completed, appears technically feasible.
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From page 172... ...
or Russian excess weapons plutonium, but major political questions remain open. The current standard CANDU design could transform 50 metric tons of weapons plutonium into spent fuel in roughly 30 to 100 reactor-years of operation, depending on the initial enrichment of the fuel.2i Canada has 20 CANDU reactors totaling about 14 GWe (46 thermal gigawatts; GWt)
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From page 173... ...
, the resulting spent fuel would be somewhat less radioactive than spent fuel from an LWR, and the isotopic composition of the plutonium in it would remain closer to that of weapons plutonium. Safeguards Issues of On-Line Refueling: Fuel can be removed from CANDU reactors at any time without shutting down the reactor, and the fuel
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From page 174... ...
Fabricating MOX fuel for CANDUs at the Hanford FMEF facility would be the most expeditious approach, with the same caveats as in the LWR case. The fabrication capacity needed to process 50 tons of excess weapons plutonium in a 25-year campaign in a single reactor using fuel containing 4.6 percent plutonium (the maximum that the manufacturer believes can be used without substantial changes to the reactors)
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From page 175... ...
Summary. Processing weapons plutonium to spent fuel in existing CANDU reactors appears technically feasible.
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From page 176... ...
SUBSTITUTION FOR CIVILIAN PLUTONIUM IN EUROPE AND JAPAN Under established civilian plutonium fuel programs, commercial reactors in Europe and Japan are scheduled to process more than 100 tons of civilian plutonium over the next decade. Plutonium storage and transport arrangements, fuel fabrication capabilities, and reactors licensed to handle plutonium for this task already exist or are planned.23 One possibility for long-term disposition of excess weapons plutonium, therefore, is to substitute this weapons material for civilian plutonium.
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From page 177... ...
Nevertheless, this approach appears considerably more promising, since it could consume both the projected surplus of weapons plutonium and the projected surplus of separated civilian plutonium, without necessarily undermining long-term plutonium fuel cycle plans in any fundamental way.26 If the necessary agreements could be reached expeditiously, this would be by far the most rapid reactor option, since the pacing steps of building new fabrication capacity and licensing the various facilities would be avoided; as noted, more than 100 tons of plutonium are expected to be processed in this way over the next decade in any case, so it would be technically possible to process the entire stock of U.S. and Russian excess weapons plutonium during that period.
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From page 178... ...
To displace civilian plutonium to be used in Europe with Russian excess weapons plutonium, however, only overland transportation would be required. Overland plutonium shipments in Europe are common and relatively noncontroversial, and the association with arms reduction should also help reduce public criticism.
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From page 179... ...
. Critics of the use of separated plutonium fuels might see an approach that tied disposition of weapons plutonium to continued large-scale MOX operations as irrevocably confirming MOX plans that might otherwise be canceled, and as conferring the political legitimacy of disarmament on MOX operations.
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From page 180... ...
The subsidy required to compensate the various parties is difficult to estimate, but might be comparable to the other LWR options. Advantages: Potentially quick; moderate cost; meets the spent fuel standard; does not lead to significant net expansion in global handling of separated plutonium; could potentially eliminate both the excess weapons plutonium and the projected excess civilian plutonium.
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From page 181... ...
The option of incorporating U.S. weapons plutonium in a substitution for civilian plutonium in existing plutonium fuel programs in Europe and Japan, however, should be kept open, though all the caveats described above would apply.
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From page 182... ...
However, if operated without reprocessing, on a once-through cycle, existing fast reactors offer some near-term capacity for transforming weapons plutonium into spent fuel, particularly as many of them have been designed to use plutonium fuel. If operated as "breeders" as originally designed, these reactors would produce more plutonium than would be fissioned (also true in the case of LWRs with one-third MOX cores)
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From page 183... ...
to be of significant value for the spent fuel option. In short, the use of existing fast reactors should not be pursued further as a major option for disposition of excess weapons plutonium.
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From page 184... ...
It has not yet met commercial acceptance, in part because of high estimated capital costs. In its recent Plutonium Disposition Study, for example, the Department of Energy found that the MHTGR was the least cost-effective of the five reactors studied.3i It is undergoing NRC design review, but is less far along in that process than the evolutionary ALWRs.
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From page 185... ...
If operated in a oncethrough mode, however, ALMRs could be used to transform weapons plutonium into spent fuel. The capital costs of these liquid-metal reactor concepts are generally higher than those of LWRs, however, and they are much less close to being licensed in the United States than are evolutionary ALWRs.
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From page 186... ...
In MINATOM's concept, the plutonium in the BN-800 spent fuel would ultimately be reprocessed and reused. Thus, although the weapons plutonium would initially be embedded in highly radioactive spent fuel (as in other spent fuel options)
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From page 187... ...
Summary of Advanced Reactors for the Spent Fuel Option. Advantages: New evolutionary or advanced reactors could meet the spent fuel standard; evolutionary designs at existing government sites might be easier to license and more acceptable to the public than the use of existing reactors for plutonium disposition.
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From page 188... ...
Excess weapons plutonium could also be vitrified-either with HLW, with other highly radioactive species, or in a glass bearing only the plutonium itself but this would add some technical uncertainties. If plutonium were vitrified along with HLW in the vitrification campaigns currently planned, the glass logs produced would be resistant to theft by virtue of their large size and mass (the U.S.
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From page 189... ...
The most straightforward way to vitrify weapons plutonium with radioactive wastes would be to incorporate it in the HLW vitrification campaigns already planned. At DOE's Savannah River Site, a multibillion dollar program to vitrify HEW, centered on the Defense Waste Processing Facility (DWPF)
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From page 190... ...
All of the planned capacity in the Yucca Mountain repository will be filled by wastes already scheduled to be produced. Therefore production of additional waste products specifically for weapons plutonium disposition (rather than piggy-backing on planned HEW vitrification campaigns)
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From page 191... ...
Introducing plutonium into Yucca Mountain would be nothing new: the nominal 50 tons of excess weapons plutonium is small compared to the 600 tons of plutonium in the spent fuel to be placed in the repository. But this plutonium would be in HEW glass, which would not otherwise contain substantial quantities of plutonium, rather than in spent fuel.
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From page 192... ...
As for the opportunities for diversion or theft of the materials, it is important that all necessary plutonium operations for the vitrification option- both pit processing and production of the plutonium-bearing glass-could be carried out at a single nuclear weapons complex site with extensive safeguards and security. Thus, the number of required transportation and storage steps, and the associated opportunities for theft, would be less than in most of the reactor options.
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From page 193... ...
The cost of a separate plutonium vitrification campaign that incorporated radioactive materials such as cesium-137 would be much higher, because the high costs of processing highly radioactive glass would then have to be borne entirely by the weapons plutonium disposition mission, rather than being shared by HLW disposal operations already planned.
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From page 194... ...
In general, Russian authorities have objected to weapons plutonium disposition options that would "throw away" the plutonium without generating electncity. Moreover, given the environmental legacy of past handling of plutonium and the widespread public distrust of government safety assurances, gaining public acceptance and licenses for a plan to bury plutonium in a repository in Russia might be difficult.
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From page 195... ...
Vitrification of excess weapons plutonium with HLW or other highly radioactive materials appears to be a feasible approach to creating a disposal form roughly as inaccessible for use in weapons as plutonium in commercial spent fuel. The technical uncertainties in this approach, however, are greater than for the MOX option.
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From page 196... ...
Institutional issues would include: · safeguards and security for the process, including possible international agreements; · licensing and local approval for plutonium vitrification operations; · the likely political impact of plutonium disposition on other countries' plutonium fuel programs; and · the likelihood of Russian government and Russian public agreement to vitrify Russian excess weapons plutonium. DEEP BOREHOLES Very deep boreholes-perhaps 4-kilometers deep-have been considered in several countries for disposal of spent fuel or HEW, and this is a possible approach for plutonium disposal as well.
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From page 197... ...
42 The committee does not believe its role is to suggest drastic changes in current waste management approaches unless they are necessary to solve the plutonium disposition problem. Hence, it would not recommend the Borehole approach for disposing of plutonium that had already been vitrified with HLW, or transformed into spent fuel in reactors, unless U.S.
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From page 198... ...
. Thus, deep boreholes represent a class of options that go a long way toward eliminating the proliferation risks posed by excess weapons plutonium, but do not go quite as far in reducing the potential breakout risks associated with this material's existence.
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From page 199... ...
Disadvantages: Readily recoverable by host government; requires further development; possibly large costs and delays in licensing a new geologic disposal approach. Conclusion: At present, because it is less fully developed, the borehole op tion ranks behind the spent fuel and vitrification options as a contender for long-term plutonium disposition, but further research could show it to be comparably attractive.
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From page 200... ...
A1though the committee has not done a full cost analysis, implementation of this option might be in the lower range of costs, probably amounting to several hundred million dollars for the nominal 50 tons of excess weapons plutonium. As with the borehole approach, however, the costs of developing and licensing the option would be far higher than the costs of implementation.
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From page 201... ...
LONG-TERM DISPOSITION 201 \ BASIC ~8 BOOSTED AL. hi, DRILLED / FIGURE 6-4 Sub-seabed disposal Source: Redrawn from JK Associates, The Subseabed Disposal Project: Briefing Book 1985(JK Associates: 1985~.
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From page 202... ...
, would be difficult, uncertain of success, time-consuming, and expensive. Given the strong resistance of many countries to placing such wastes anywhere in or below the ocean, the committee does not believe that such an approach should be pursued if it is merely to address excess weapons plutonium a problem that only two countries (the United States and Russia)
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From page 203... ...
This option would also face major problems of public and institutional acceptance. Finally, the material would be recoverable by the state that emplaced it, providing a plutonium mine with substantially more plutonium in each ton of rock than there is gold in some mines that are profitably mined today, and with dramatically lower near-term radiological hazard than is the case for the spent fuel or vitrification options.
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From page 204... ...
As discussed in the case of the deep-borehole option, such recoverability means that these approaches would do less to reduce breakout risks or potential negative impacts on the arms reduction and nonproliferation regimes than would other approaches. Recoverability could increase the prospects of political acceptance by the Russian government, however.
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From page 205... ...
Beyond the Spent Fuel Standard Although the spent fuel standard is an appropriate goal for excess weapons plutonium disposition, further steps should be taken to reduce the proliferation risks posed by all of the world's plutonium stocks, including plutonium in spent fuel. Separated reactor-grade plutonium poses risks less than, but comparable to, those of separated weapons-grade plutonium.
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From page 206... ...
the steps leading to the elimination options would themselves generate security risks beyond those of the nonelimination options (as could be the case, for example, with some concepts for eliminating the plutonium by repeated reprocessing and reuse)
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From page 207... ...
Moreover, assuming that the payload remained intact in the event of an accident, it would fall to earth, and its possible recovery by potential proliferators would pose a major security risk. As noted earlier, options for going beyond the spent fuel standard to total elimination of excess weapons plutonium that involve substantial additional costs, risks, or delays are not justified unless they are applied to the much larger stock of civilian plutonium as well.
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From page 208... ...
The committee notes, however, that international standards for disposition of low-level radioactive wastes in the oceans, administered by the International Atomic Energy Agency (IAEA) , include important factors not considered in the U.S.
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From page 209... ...
With such repeated reprocessing and reuse, virtually any type of reactor could in principle be used in an elimination option: while only fast-neutron reactors can fission all isotopes of plutonium, reactors with a thermal neutron spectrum, such as LWRs, can in principle transmute those isotopes they cannot fission into other isotopes they can, as part of their normal operations. Policymakers considering these elimination options should be under no illusions concerning the scale of the effort required.
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From page 210... ...
Institutional arrangements lasting many decades or even centuries would be required to manage such an effort.46 Whether or not such a plutonium elimination approach should be pursued is a subject integrally tied to the future of nuclear power and fuel cycles, going well beyond the committee's charge. If it were to be pursued, it is premature to select a particular reactor system as the preferred option for this purpose.
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From page 211... ...
This is because even without such nonfertile fuels, simply increasing the plutonium concentration in ordinary fertile fuels would substantially reduce the amount of new plutonium produced for a given amount of energy generated (or for a given amount of weapons plutonium burned)
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From page 212... ...
212 LONG-TERM DISPOSITION Accelerator-based Conversion (ABC)
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From page 213... ...
Additional research is desirable to clarify the issues involved in elimination options in general and to identify the most promising options for that purpose. CONCLUSIONS Figure 6-5 summarizes the committee's judgments concerning the longterm disposition options described in this chapter.
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From page 216... ...
fuel cycle and nonproliferation policies described in the text: those options involving the use of weapons plutonium in reactors would send the signal that the United States approved of such use, at least for this limited purpose, whereas the disposal options would send the signal that even for the pressing problem of plutonium disposition, the United States did not approve of the use of plutonium fuels. In this column, therefore, the committee simply indicates whether the option would or would not use plutonium in reactor fuel, rather than attempting a high, moderate, and low categorization.
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From page 217... ...
are rated moderate in all categories except technical uncertainty, which remains low, as in the case of LWRs with onethird MOX, because the modifications needed to accommodate full-MOX cores are not sufficient to create substantial uncertainties or require major development. CAND Us, like full-MOX LWRs, are rated moderate under all criteria except technical uncertainty, which is rated low, because this option would not require a major development program.
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From page 218... ...
Similarly, it is rated as having high ES&H risks and acceptance difficulties. Existing LMRs without reprocessing are less susceptible to across-theboard ratings than some of the other options because there are wide variations in the design and characteristics of these facilities; moreover, some are in countries where the excess weapons plutonium is located, whereas for others, the plutonium would have to be shipped and agreements negotiated.
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From page 219... ...
MHTGRs with reprocessing are rated as having high technical uncertainty, since a reprocessing approach has not been pursued for HTGRs in recent years, and such a plutonium elimination objective has not been examined in detail. Like LWRs and CANDUs with reprocessing, they are rated as having high risks of handling, because of the repeated reprocessing and use of fully separated plutonium that would be required.
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From page 220... ...
· 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.
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From page 221... ...
· 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.
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From page 222... ...
Adequate information must be made available to give substance to the public's participation. · Although the committee did not conduct a comprehensive examination of the proliferation risks of civilian nuclear fuel cycles, which would have gone beyond its charge, the risks posed by all forms of plutonium must be addressed.
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