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~2 Criteria for Comparing Management and Disposition Options The primary goal in the management and disposition of excess weapons plutonium should be to minimize the risks to national and international security posed by the existence of this material. Accordingly, the discussion of criteria for comparing the possible approaches in this report begins with these security risks. The issues of timing and capacity how quickly an approach can be put into operation and how rapidly it can process weapons plutonium thereafter are tightly intertwined with other aspects of security, and these matters are treated together here. The report then turns to criteria related to economics; environment, health, and safety; and other policies and objectives. This presentation of criteria aims to be comprehensive, as a guide for fur- ther analyses. The constraints of this study, however, did not permit applying them with the same rigor described below; instead, in developing its recom- mendations, the committee has applied these criteria in more general terms. CRITERIA RELATED TO SECURITY, TIMING, AND CAPACITY As described in Chapter 1, the goal of minimizing security risks from ex- cess weapons plutonium can be divided into three objectives: 1. to minimize the risk that either weapons or fissile materials could be ob- tained by unauthorized parties; 61

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62 CRITERIA FOR COMPARING OPTIONS 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 control mechanisms and incen- tives designed to ensure continued arms reductions and prevent the spread of nuclear weapons. The preceding chapters have described these risks. The relative importance of the various risks may change substantially over time, in ways that are difficult to predict in some cases. U.S. consideration of the risks associated with the various options for man- agement and disposition of its own plutonium must be informed by an aware- ness of the potential linkages between U.S. choices and the choices that may be made in the former Soviet Union. U.S. policy could affect the management and disposition of excess weapons plutonium in the former Soviet Union in a vari- ety of ways-ranging from simply setting an example on the one hand, to fi- nancial assistance, negotiated agreements to pursue particular approaches, or outright purchase of former Soviet weapons plutonium on the other. Moreover, what is done with excess weapons plutonium in the United States and the for- mer Soviet Union could affect, for good or ill, the fate of the substantially larger (and still growing) quantities of separated and unseparated plutonium dis- charged from civilian nuclear power reactors worldwide. Characterizing the Risks Candidate disposition approaches typically consist of several steps, begin- ning with intact nuclear weapons and proceeding through dismantlement and intermediate storage to long-term disposition. Long-term disposition itself is likely to involve some number of intermediate processing, storage, and trans- port steps, ending with either the physical destruction of the plutonium (by fis- sion or transmutation) or its disposal in a form and location where it is in- tended to remain indefinitely.2 Evaluating the security benefits and liabilities of each approach requires an assessment of each step within it, with respect to each type of opportunity or threat. The risks of theft and breakout differ greatly in their urgency and charac- teristics. As noted in Chapter 2, the risk of theft of fissile materials in the former Soviet Union is serious and urgent, given the political, social, and eco- nomic turmoil there. Theft of as little as several kilograms of material could pose major security risks. ~ Not all excess weapons plutonium will begin in the form of intact nuclear weapons, however, there are substantial quantities in scrap and residues in the nuclear weapons complexes today. 2 Or, to be more specific, until it decays radioactively (with a half-life of 24,000 years) to uranium-235 (U-235 - also a potential weapons material, with a half-life of 700 million years.

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CRITERIA FOR COMPARING OPTIONS 63 By contrast, any breakout effort large enough to affect the strategic balance would require the use of much larger quantities of fissile material (in order to make thousands of weapons, rather than just a few). However, any barriers to inhibit either the United States or Russia from a major breakout could only in- crease the time, cost, observability, and political inconvenience (such as that arising from having to abrogate agreements) involved in doing so. The United States or Russia could, at any time it chose, either recover plutonium from nearly any form and location on its territory where it might exist, or produce new plutonium or highly enriched uranium (HEU). Those potential prolifera- tors who lack the technology and knowledge associated with a large nuclear weapons complex or an advanced civilian nuclear program would not have as many options. The risks of theft or diversion associated with a particular step in this process depend on four classes of factors: 1. The state of the plutonium, including: a) its chemical form (for example, plutonium metal, oxide, carbide, or nitrate, of which metal is most convenient); b) its isotopic composition (the fraction of plutonium-239 (Pu-239), the most attractive isotope for bomb making, versus the fractions of Pu-240, Pu- 241, Pu-242, and Pu-238~; c) any admixture of impurities (such as other metals, oxides, or carbides; fission products; or other neutron absorbers, which, variously, affect chemical processing requirements and radiological hazard to bomb makers); and d) its configuration (for example, part of an assembled warhead, intact pit, deformed pit, ingot, powder, ingredient of fuel element). 2. Stockpiles and transportation risks, namely: a) inventories or annual throughputs (as appropriate) of the various facilities storing or handling plutonium; b) the amount of time the inventories remain in the step in question and the duration of the throughputs; and c) the number of times plutonium is transported from place to place (when the barriers, described below, are likely to be smaller), and the distance and duration of these trips. 3. Barriers to the theft or diversion, namely: a) barriers inherent in the form of the material (for example, dilution, meas ured by the percentage of plutonium in the mixture, and gamma radiation dose, measured in roentgen-equivalent-man (rem) per hour at a specified time and distance); b) engineered barriers (for example, massive containers, vaults, buildings, fences, special transport vehicles, detectors, alarms);

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64 CRITERIA FOR COMPARING OPTIONS c) geographic and geologic barriers (for example, site isolation, difficult terrain, burial depth, difficulty of excavation and tunneling); and Institutional barriers (for example, proximity and capability of guard forces, intensity and reliability of monitoring). 4. Characteristics of the threat, including: a) potential complicity of the custodial organization or of individuals within it; b) capabilities of attacking forces (numbers, weapons, training, organization, determination) in the case of forcible theft; and c) knowledge, skills, money, technology, and organization available to the prospective bomb-makers. The foregoing considerations suggest a matrix approach to characterizing the security implications of different options for the disposition of weapons plu- tonium, in which the rows of the matrix are the steps in a particular option, and the columns portray: i. qualitative assessments of the attractiveness of the plutonium as a raw mate rial for weapons, considering factors la-d, above; ii. numerical measures of quantity, time, and dilution (factors 2a-c, and 3a); and iii.qualitative evaluations of vulnerability as governed by the interaction of barriers (3a-d) with threat characteristics (4a-c) for the main classes of threats. This procedure is illustrated in Table 3-1, which outlines how it would be applied to the conversion of weapons plutonium into spent light-water reactor (LWR) fuel. The tabulation lists the 10 steps involved, together with the date when each would begin. This would be followed by an assessment of each step with regard to three characteristics: Attractiveness. Assessing the attractiveness of plutonium in particular forms to prospective bomb-makers is, inherently, a complex and potentially contentious undertaking, involving the assignment of weights to the various relevant characteristics. Indeed, attractiveness is likely to depend not only on the characteristics of the plutonium but on those of the bomb-makers, which means that, in principle, different attractiveness levels might correspond to different classes of threat. In particular, one significant component of the risk of theft is likely to be theft by parties who do not have the capability to process the material or fabricate it into weapons, for sale to those who do. Forms of plutonium that would be quite difficult for unsophisticated parties to remove, store, and transport such as those emitting intense radioactivity are likely to pose major obstacles to this form of theft, even if they would pose significantly smaller barriers to parties with the sophistication required to fashion a nuclear weapon.

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66 CRITERIA FOR COMPARING OPTIONS Quantitative Factors. The first two columns under "quantitative factors" in the security risk matrix (inventory or throughput, and average time in the step or duration of the step) are indices for which higher numbers mean higher risks, while the third and fourth columns, dilution and gamma dose, are indices for which higher numbers mean lower risks. For storage steps, the product of inventory and average residence time (equivalent to the integral under a quan- tity-versus-time curve) is a particularly informative quantitative index of risk at given attractiveness and vulnerability levels. Vulnerability. The characterization of vulnerability here is based on three reference classes of threat: covert diversion by the state controlling the facility, forcible theft, and covert theft. Vulnerability at each step to each of these threats would probably be best characterized simply as "low," "medium," or "high," based on judgments about the effectiveness of the relevant barriers against the indicated threats. Any more discriminating characterization than this probably would not be warranted in light of the uncertainties associated with threats and barriers alike.3 Since, in many cases, the plutonium leaves a step in a form different from that in which it entered, a tabulation such as Table 3-1 should show both initial and final attractiveness levels for each step. Table 3-2 shows the five-level "attractiveness" classification specified in the relevant U.S. Department of Energy (DOE) order,4 which could be used to fill out the "attractiveness" columns of Table 3-1, although it does not distin- guish among the different types of threat described above. As the table shows, assembled weapons are considered to be the most attractive items for theft or diversion, and are always in the top safeguards category (meaning the most care required in security and accounting). Relatively pure plutonium or HEU is judged to be one step less attractive, but still should be treated as being in the top safeguards category, even in amounts somewhat smaller than those needed to produce a weapon. Other materials require progressively lower levels of pro- tection. Table 3-3 shows some of the relevant characteristics of different forms of plutonium, ranging from intact pits at the top of the table to various forms of spent fuel or high-level waste (HLW) glass at the bottom. Characteristics listed include such factors as the size and weight of the item in question (which help determine how easy it is to steal), the radioactivity (which helps determine both 3 It is not useful to specify vulnerability levels for overt diversion in this format, because (i) as long as the plutonium remains on the territory of the state from whose weapons it came, that state will have the resources to overcome virtually any barriers if it chooses to do so (as noted above), meaning that the vulnerability can be simply characterized as more or less proportional to the attractiveness level; and (ii) if the plutonium is not on the territory of the original possessor state, the category of `'overt diversion" is not really meaningful. The options available to the original possessor state in the latter instance amount to forcible theft and covert theft, the vulnerability to which is characterized. 4 See U.S. Department of Energy, Order 5633.3A, "Control and Accountability of Nuclear Materials," February 12, 1993.

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68 CRITERIA FOR COMPARING OPTIONS TABLE 3-3 Some Secunty-Related Charactenstics of Plutonium in Different Forms Form MassMax. perItem ItemDim. (kg)(cm) ca.4cat 10 69 Pu Gamma Pu Conc. Dose Rate per Item (kg/ (remO at (kg) kg) Surface 1 Meter Intact pit (WPu metal) RPu metal sphere, 8-phase PuO2 powder, WPu Same, RPu MOX fuel pellet, WPu Same, RPu MOX fuel rod, WPu Same, RPu MOX fuel assembly, WPu Same, RPu MHTGR WPu fuel block Irradiated MOX fuel assembly. WPu ca.4 (powder @ 1 g/cm3) (powder @ 1 g/cm3) 0.006 0.006 2.5 2.5 658 658 100 13x10-4 13x 10-4 4100.1 4100.1 41025 41025 800.8 0.88 0.88 0.05 0.05 0.04 0.04 0.038 0.038 0.008 0.80.002 170.03 10.009 200.2 0.051 x 10-6 12x 10-5 0.031.4 x 10-4 0.73x 10-3 0.033 x 10-3 0.70.06 0.50.02 0.4 MWd/kgHM, 2 years658 410 23 0.03550,0004,500 10 years658 410 23 0.03544040 30 years658 410 23 0.03519017 100 years658 410 23 0.035373 40 MWd/kgHM, 10 years658 410 18 0.0274,40004,000 30 years658 410 18 0.02720,0001,800 100 years658 410 18 0.0274,000360 50 MWd/kgHM, 10 years658 410 9 0.01455,0005,000 30 years658 410 9 0.01425,0002,300 100 years658 410 9 0.0145,100460 Borosilicate glass log with WPu and high-level wastes Small, 2% Pu, 20% HEW 250 50 40.02 not calculated Large, 2%Pu,20%HLW 2,200 300 340.02 5,000 900 Same,+ 10 years 2,200 300 340.02 4,000 720 Same, + 30 years 2,200 300 340.02 2,500 450 Same,+ 100 years 2,200 300 340.02 500 90 NOTE: Max. = maximum, dim. = dimension, cone. = concentration; WPu = weapons plutonium, assumed to contain 0.2 weight percent americium-241 (from initial 0.4% Pu-241, aged 14 years); RPu = reactor plutonium, assumed to contain 4 weight percent americium-241 (from initial 9% Pu-241, aged 12 years); 8-phase = delta-phase, one of the six crystalline phases in which plutonium occurs (the two most commonly mentioned in connection with nuclear weapons are alpha phase (density 19.6 g/cm3) and delta phase (density 15.7 g/cm3)); MOX = mixed-oxide; MHTGR = modular high- temperature gas-cooled reactor; MWd/kgHM = megawatt-days (of thermal energy output) per kilogram of heavy metal; HEW = high-level waste. All characteristics for intact pits are for illustrative purposes only; actual dimensions are classified. Detailed notes for this table can be found in Management and Disposition of Excess Weapons Plutonium: Report of the Panel on Reactor-Related Options (Washington D.C.: National Academy Press, 1994).

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CRITERIA FOR COMPARING OPTIONS 69 the ease of theft or diversion and the difficulty of separating the plutonium), and the like. The foregoing discussion addresses the risks of theft and breakout, but the risks and opportunities of a particular management and disposition approach with respect to the third category of security issues (influences on efforts to reduce nuclear arsenals and stem the spread of nuclear weapons) are more dependent on political perceptions and thus inherently more difficult to charac- terize. These risks and opportunities will depend in part on: 1. Timing, that is, the speed with which various steps (such as dismantlement of weapons, implementation of safeguards over excess fissile materials, and long-term disposition of fissile materials) can be accomplished. This in- cludes the relation of these steps to the timing of other relevant international events, such as Ukrainian nuclear weapons decision making and the April 1995 NPT extension conference. 2. Transparency, that is, the degree to which it can be demonstrated to relevant members of the international community (including Russia, the United States, the other former Soviet states with nuclear weapons on their soil, other declared and undeclared nuclear-weapon states, and non-nuclear- weapon states) that steps that have been announced, ranging from retirement of deployed weapons through dismantlement, storage, and long-term dispo- sition, are in fact being carried out. 3. Constraints, that is, the degree to which states such as the United States and Russia accept limits on their nuclear weapons capabilities that would be dif- ficult and costly to reverse (thus strengthening the arms reduction regime and demonstrating their compliance with the NPT requirement for negotiat- ing in good faith toward disarmament) and that parallel in some respects the constraints imposed on other countries in the name of nonproliferation (thus reducing the discrimination inherent in the nonproliferation regime and im- proving prospects for approval of an indefinite or long-term extension of the NPT and strengthened safeguards). The relation of these issues to a reductions and transparency regime for nuclear weapons and fissile materials is discussed in more detail in Chapter 4. Standards Characterizing the security risks of the various disposition options in the ways just described will provide insight into the areas of greatest risk within each option and a basis for comparing overall risk among options. These com- parisons will inevitably be judgmental because they involve different attributes and classes of risk and opportunity, many of which can only be characterized in a general way. There is no defensible way to compute a single quantitative index of overall risk for each option; doing so would require agreeing on nu- merical values and relative weights for each relevant characteristic and threat.

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70 CRITERIA FOR COMPARING OPTIONS Within the constraints of this study, the committee was unable to pursue the approach just described for each of the options considered. That task should be pursued in subsequent analyses. To be most useful, however, criteria should not only provide a basis for relative comparisons among options, but also provide guidance as to "How good is good enough?" As outlined in Chapter 1, two clear standards for man- aging the stages of this process should be set: the stored weapons standard, meaning that to the extent possible, the high standards of security and account- ing applied to storage of intact nuclear weapons should be maintained for these materials throughout dismantlement, intermediate storage, and long-term dis- position; and the spent fuel standard, meaning that options for the long-term disposition of weapons plutonium should seek to make this plutonium roughly as inaccessible for weapons use as the much larger and growing stock of pluto- nium in civilian spent fuel. Further steps should be contemplated, however, to move beyond the spent fuel standard and reduce the security risks posed by all of the world's plutonium stocks, military and civilian, separated and unsepa- rated; the need for such steps exists already, and will increase with time. More specific criteria related to technical options for storage are described and discussed in Chapter 5, while a set of criteria relevant to long-term dispo- sition- including minimizing the time required for disposition, minimizing the risks of theft or diversion in the various steps involved, and minimizing the risks of recovery of the plutonium in its final form are addressed in Chapter 6. CRITERIA AND ISSUES IN ECONOMIC EVALUATION OF ALTERNATIVES The monetary costs (or benefits) of alternative approaches to the manage- ment and disposition of weapons plutonium are of secondary importance compared to the security aspects. The security risks associated with this mate- rial are so great that it is difficult to imagine choosing an approach that was significantly riskier than another because it would save money-all the more so because the total sums involved are unlikely to be nearly as large as those that the United States and the former Soviet Union routinely invested in the past in attempts to buy security against nuclear weapon dangers. Nevertheless, the economic dimension of alternative disposition ap- proaches should be examined to assist in ranking approaches that are not readily distinguishable on security grounds, to facilitate planning for the in- vestments that will be required for the approach chosen, and to correct some of the misimpressions put forward in recent years concerning the economic merits of the various approaches.

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CRITERIA FOR COMPARING OPTIONS 71 Principles and Pitfalls in Cost Comparisons Comparison of the economics of alternative approaches requires that the costs and revenues be estimated on a consistent basis. Such calculations can be quite complex, and the range of conventions and assumptions routinely used in carrying them out is wide. Relevant factors include: 1. the treatment of inflation; 2. whether the activities are carried out by government or civilian entities, or a combination, and corresponding assumptions about the real cost of money appropriate for the entities operating them, and property taxes and insurance costs associated with the facilities and operations; 3. conventions and assumptions relating to the components of the capital in- vestments associated with the activities, including a) the relevant costs of land, materials, labor, and purchased components in the region where the approach will be implemented; b) the inclusion of indirect as well as direct costs; c) the size of the "contingency" factor allowing for growth in construction costs beyond the baseline estimate; d) the inclusion or exclusion of interest on investments made before the op- erational phase commences (often termed "interest during construction," although in principle the category is broader); 4. the degree of comprehensiveness, including costs of all the facilities and operations needed to perform the relevant mission; 5. the means by which subsidiary benefits of plutonium disposition operations (such as the generation of electricity) are taken into account in the economic calculations; 6. the treatment of "sunk" costs in relevant facilities and operations, that is, costs incurred prior to the current consideration of the possible use of particular facilities and operations for the management and disposition of weapons plutonium; and 7. the operational lifetime of the facilities (or, in some cases, the period over which the investment in them is to be written off). Variations and inconsistencies in the treatment of these factors make it practically impossible to derive informative conclusions about costs of alterna- tives from direct comparison of final cost estimates obtained in different studies of the individual disposition approaches; rather, it is necessary to reconstruct a consistently based set of estimates starting from the building blocks (such as estimates of direct construction costs, or of labor and materials requirements) that such studies provide.S For projects extending over several decades, consistent assumptions con cerning the rate of inflation and the real cost of money are particularly impor s Studies that offer estimates of costs without providing sufficient detail about the derivation of these to permit such reconstruction are not useful for purposes of making systematic comparisons.

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76 CRITERIA FOR COMPARING OPTIONS ISSUES AND CRITERIA RELATING TO ENVIRONMENT, SAFETY, AND HEALTH The greatest dangers to public welfare associated with the existence and disposition of weapons plutonium are unquestionably those connected with na- tional and international security. The preeminence of these security dangers, however, should not obscure the need for careful attention to the environment, safety, and health (ES&H) risks implied by the different approaches to weapons dismantlement, fissile material storage, and long-term disposition of weapons plutonium. As is well known, the U.S. nuclear weapons complex has left a heritage of ES&H problems, and those problems in the former Soviet Union's weapons complex are still worse. The United States is currently spending more than $6 billion a year on the cleanup effort, without making a significant dent in the problem so far. Damage from plutonium production, separation, and processing is a significant part of this ES&H legacy. It is essential that reductions in these vast nuclear arsenals not exacerbate these problems. The committee believes that the goal of reducing the security risks associated with excess nuclear weap- ons and fissile materials can and should be accomplished subject to reasonable ES&H constraints. It is very important that the governments involved express in the strongest terms their commitment to respect such constraints and demon- strate this commitment by promulgating an appropriate set of ES&H criteria for the plutonium disposition process. Additional institutional mechanisms and resources may be required. The committee believes that in the United States these processes must: 1. comply with existing U.S. regulations (and subsequent modifications) gov- erning allowable emissions of radioactivity to the environment, and allow- able radiation doses to workers and the public from civilian nuclear energy activities; 2. comply with existing international agreements and standards (and subse- quent modifications) covering radioactive materials in the environment; and 3. not add significantly to the ES&H burdens that would be expected to arise, in the absence of the weapons plutonium disposition problem, from responsible management of the environmental legacy of past nuclear weapons produc- tion, and from responsible management of the ES&H aspects of past and future civilian nuclear energy generation. In Russia or other countries, the same criteria should apply, with the sub- stitution of those countries' domestic regulatory framework for that of the United Stateside (For a description of current U.S. and international regula- tions, see "Some Relevant Standards Limiting Doses and Emissions," p. 78.) iIn some cases, this may mean that Russian activities will operate under less stringent criteria than in the United States. But insisting that finite ES&H funds in Russia be spent on fully complying with U.S. regulatory standards in the management of excess weapons and plutonium, when there is so

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CRITERIA FOR COMPARING OPTIONS 77 In proposing this set of criteria, the committee understands that some may consider some of the relevant national and international regulations and guide- lines unduly restrictive (meaning that they impose economic or other burdens disproportionate to their ES&H benefits), while others will argue that some are too lax. This study is not the place to examine these issues. The committee be- lieves a formulation like the one proposed here should gain widespread accep- tance as a practical basis for proceeding, and that it would be both unnecessary and unwise to allow the objectives addressed in this study to become hostage to reaching agreement on modifying any of the applicable national and interna- tional ES&H standards. The committee believes that the criteria outlined above are both necessary and sufficient for ensuring adequate protection for ES&M. The first two criteria are necessary because to argue that looser standards are needed to get the job done would almost surely (given the history of similar claims by the nuclear weapons complexes in the United States and Russia) generate such strong op- position as to paralyze the processes of decision making and implementation. The resulting delay could seriously undermine the security goals driving the weapons plutonium disposition program. The third criterion is necessary be- cause existing standards on emissions, doses, and disposition of radioactivity in the environment do not cover all of the ES&H characteristics of potential con- cern. To argue that the third criterion need not be met that is, that manage- ment and disposition of excess weapons plutonium should be allowed to create a significant increase in the ES&II burdens of the nuclear weapons complexes or of civilian nuclear power would also be likely to generate widespread ob- jection and intolerable delay. Interpretation of these criteria requires understanding the effects of ioniz- ing radiation. Few if any classes of environmental hazards to human health have been studied more thoroughly than the radiological hazards from nuclear energy activities, but controversy remains. Most of the ES&H risks of pluto- nium management and disposition would involve low doses of radiation spread over long periods of time, and the effectiveness of such low doses in causing human cancers and other health effects is a subject of considerable uncertainty. Given the high background of cancer in the U.S. population (about 20 percent of all deaths), the long latency periods for cancer, the wide variations in behav- ior and other factors among the population, and the great variability of natural background radiation, it is difficult to establish a firm epidemiological basis for estimating the health effects of very low doses. The major national and interna- tional regulatory and advisory bodies dealing with radiation assume, for pur- poses of setting standards and estimating health effects, that the effect of radia much else to do in cleaning up the legacy of environmental contamination in the former Soviet Union, does not seem a wise request. For the states of the former Soviet Union to be able to achieve the objectives the committee outlines, however, while maintaining appropriate ES&H goals, may require . . specla . assistance.

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78 CRITERIA FOR COMPARING OPTIONS lion can be extrapolated linearly down to the level of natural background radiation, but this could be either an underestimate or an overestimate of the risky 1 This linear assumption is particularly convenient because it means that a given "population dose" the product of the size of the exposed population and the average dose to that population, measured in person-rem would produce the same number of effects (primarily cancers) regardless of whether it was produced by a particular dose being given to a million people, or a hundredfold larger dose being given to lO,OOO people. With this linear assumption, current 1 l National Research Council, Committee on the Biological Effects of Ionizing Radiation, Health Effects of Exposure to Low Levels of Ionizing Radiation (BEIR V) (Washington, D.C.: National Academy Press, 1990).

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CRITERIA FOR COMPARING OPTIONS 79 estimates suggest that for low doses over prolonged periods, one excess cancer death would be expected for every 2,500 person-rem of exposure, although this figure has wide bounds of uncertainty. The argument for the sufficiency of the committee's three criteria has three parts: 1. The standards on emissions, doses, and disposition of radioactivity in the environment have been constructed to ensure that the radiological risks to the most exposed members of the public from the routine operation of nu- clear facilities in compliance with these standards are much lower than the risks of the same types experienced by individuals in the same population

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80 CRITERIA FOR COMPARING OPTIONS from other causes. The doses to the typical workers or members of the public are much smaller than those to the most exposed. 2. Those radiological risks from plutonium disposition that would not neces- sarily be adequately limited by criteria 1 and 2 would be confined by crite- rion 3 to be a small addition to the risks of these kinds that exist or will exist from responsibly managed nuclear electricity generation and cleanup of the nuclear weapons complexes. Given that society is now bearing these risks in connection with the benefits of electricity supply and the need to manage the cleanup and consolidation of the nuclear weapons complexes, a small addi- tion to them is not too high a price to pay for the security benefits of weapons plutonium disposition. 3. The nonradiological ES&H impacts from plutonium disposition in such categories as the alteration of land and vegetation for facility construction, consumption of water, emission of chemical pollutants, and the usual array of industrial hazards to workers (falls, maiming by machinery, electrical shock, and so on) would similarly be limited, by the implementation of cri- terion 3, to small additions to the current and projected risks of this kind re- sulting from civilian nuclear power and nuclear weapons complex cleanup. These nonradiological risks are in any case likely to be less significant for these missions than the radiological ones. It would pose a genuine dilemma, of course, if the only dismantlement, storage, or disposition approaches capable of meeting reasonable security crite- ria turned out to be incapable of meeting reasonable ES&H criteria. The com- mittee's review of the options argues, fortunately, that this is not likely to be the case. There is, however, a likely trade-off, as there often is, between meeting the sorts of ES&H criteria listed and conducting similar operations at minimum cost. Since the costs of the most promising approaches, even with these ES&H criteria included, are low compared to other costs involved in the pursuit of comparably important security goals and since failure to meet such ES&H criteria could lead to public rejection and court challenges causing delays long enough to have major adverse security consequences resolving the ES&H- economics trade-off in favor of the ES&H goals should be an obvious choice in this case. ES&H and the Three Stages of Reductions Dismantlement, fissile material storage, and long-term disposition of weapons plutonium can affect workers, members of the public now living, and future generations (as well as the nonhuman environment) in a variety of ways. Some effects result from the radiological properties of the materials used (such as cancer risks from inhalation of plutonium), and some result from nonradi- ological factors such as accidents similar to those that occur in other industries. They can also be divided into those that result from routine operations and

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CRITERIA FOR COMPARING OPTIONS 81 those that result from accidents. In considering these issues, it is legitimate to focus on those ES&H impacts with the potential to be large enough either to affect choices concerning the most appropriate management approaches or to require mitigation efforts involving a significant fraction (perhaps 10 percent or more) of the total cost of the operation in question. As noted above, this is likely to mean radiological issues rather than nonradiological ones. An assessment of the ES&H risks in these processes should focus, like the economic assessment, on the net effects of these activities in relation to what would have occurred had these excess weapons and materials not existed. As with the economic analysis, the two main possibilities are dealing with these weapons and materials in facilities that: 1. would have operated in any case (in which case what should be measured is the net additional ES&H impacts of involving the weapons plutonium in their operation); or 2. would not otherwise have operated (such as a reactor built expressly for that purpose). In the second case, if the facility produces no other product, then the total ES&H impact of the operation must be charged against the plutonium disposi- tion mission. If the facility does produce something that would otherwise be produced in other ways (such as electricity), then the ES&H impacts should in principle be compared to those of producing the same product in other ways. This may involve apples-and-oranges comparisons (such as comparing radio- logical effects of nuclear power to greenhouse effects of fossil fuels) that are so difficult as to be virtually impossible to undertake, so that it may be better sim- ply to consider the total ES&H impact in this case as well. Dismantlement Dismantlement in general consists of activities that would not otherwise be taking place; therefore, their ES&H impacts must be charged completely to the reductions process. The main ES&H impacts of these processes are: risks of nuclear or conventional explosions during dismantlement (neither of these has ever occurred, at least in the United States); radiation exposure to workers in routine operations; radiation exposure to workers or the public in the event of accident (such as an accidental nuclear chain reaction); chemical exposures to workers and the public (for example, from the han- dling of hazardous materials in nuclear weapons or from burning conven- tional explosives); and risks from disposing of a variety of weapons components as waste.

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82 CRITERIA FOR COMPARING OPTIONS Compared to other activities in the nuclear weapons complex, dismantle- ment operations are relatively "clean," because no processing of nuclear mate- rials is involved (see Chapter 4~. Intermediate Storage The ES&H risks in storing fissile materials will depend significantly on the forms in which the material is stored, the processing (if any) required to con- vert available materials into those forms, and the design of the storage facili- ties. Another critical factor is the length of time over which storage is likely to extend, particularly if it is so long that there is some risk that ES&H protection measures might erode. The primary routine ES&H impact of plutonium storage would be radiation exposure to workers within the storage facility (such as those checking and moving the storage canisters, if these activities were not conducted robotically). The primary potential accidental ES&H impact of plu- tonium storage that must be guarded against is the potential for worker or public exposure to plutonium released in the event of an accident (for example, as a result of a plane crash, see Chapter 5~. Long-Term Disposition In general, long-term disposition of plutonium is likely to be the stage with the most significant ES&H impacts, because it is likely to require substantial processing of plutonium and plutonium-bearing waste streams. If long-term plutonium disposition is to be carried out in nuclear reactors, and those reactors would have operated anyway, the main changes from the operations that would otherwise occur would include: conversion of weapons plutonium metal to plutonium oxide (for LWRs and some other but not all reactor types); mixing the plutonium oxide with uranium oxide (for LWRs and some other reactor types) and fabricating the plutonium-bearing fuel; storage and transport steps associated with the preparation of the fuel, its delivery to the reactor, and its storage there prior to use; reduction in the amount of uranium mined, milled, converted, enriched, and fabricated, by virtue of the substitution of plutonium-bearing fuel for some of the uranium-only fuel that would otherwise have been used; any changes in the ES&H characteristics of reactor preparation, operation, and maintenance as a result of the use of weapons plutonium in its fuel; and any changes in the ES&H characteristics of waste management that result from the use of weapons plutonium in the fuel including spent fuel storage and transport; further high-level-waste processing, if any; emplacement and residence in a geologic repository (including the potential long-term risks of 1

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CRITERIA FOR COMPARING OPTIONS 83 criticality in the repository); and management of low-level and transuranic wastes. Among these items, particular attention needs to be given to the possible impacts of weapons plutonium use on reactor safety and on the disposal of the resulting nuclear waste. It should be noted that the additional troublesome ES&H issue in current nuclear power practice the radiation doses to current and future generations from the tailings at uranium mines and mills-can only be diminished (albeit modestly) by the addition of weapons plutonium, since such addition would reduce the quantity of uranium that needed to be mined and milled. Among the ES&H issues that are not particularly problematic in current practice, the one most likely to need special attention with the addition of weapons plutonium is the occupational risk from fuel fabrication where the far higher inhalation toxicity of plutonium per gram, compared to that of uranium, calls for special precautions that add significantly to the cost of fabrication. If the plutonium is mixed with high-level nuclear wastes in a method of processing and managing these that would have been used anyway (such as vitrification), the alterations to the baseline waste operations that would need to be considered include: conversion of the weapons plutonium metal to whatever form is required as input to the waste-processing operations, and of transporting the plutonium to the waste-processing facility and storing it there; addition of the plutonium to the ES&H characteristics of the waste-processing operations, including particularly any potential criticality problems in waste processing and storage, and of measures taken to offset this potential; and effects of plutonium addition on the ES&H characteristics of waste storage, transport, and emplacement and residence in a geologic repository (including the potential long-term risks of criticality in the repository). Although all of these alterations to the baseline effects of waste operations will need attention, the second and third can be expected to be the most difficult. As noted above, in cases where long-term disposition involves primarily activities that would not otherwise have been undertaken, one must demonstrate that the total ES&H impacts are not unreasonable in exchange for the benefits of the operation that is, reducing the plutonium's security risk. In the case of use in reactors, public concern has rightly focused on the risk of reactor accidents. Available probabilistic risk assessments of the risks of re- actor accidents involve substantial uncertainties. Nevertheless, the available data, with all the caveats that must be attached to them, indicate that the health Tooth of these issues are addressed in more detail in Management and Disposition of Excess Weapons Plutonium: Report of the Panel on Reactor-Related Options (op. cit.).

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84 CRITERIA FOR COMPARING OPTIONS and safety impacts of current nuclear electricity generation in the United States are not unreasonable either in absolute terms or in comparison to the impacts of the main current source of U.S. electricity supply (coal). Hence, the committee believes the ES&H standards it has outlined can be met for the case of reactors that would not otherwise operate, as long as the addition of plutonium does not significantly increase the ES&H impacts of these reactors. Therefore the analy- sis must focus on the additional risks resulting from plutonium use, in a way similar to those for reactors that would be operating in any case. For the disposal options, the most important single ES&H issue in most cases will be preventing plutonium release into the environment (including over the very long term) in ways that would violate regulatory criteria. Accident scenarios, of course, must be considered in these cases as well. OTHER CRITERIA In addition to the security, economic, and ES&H criteria just described, approaches to management and disposition of excess weapons plutonium must be acceptable to both the public and the relevant institutions, and should, to the extent possible, avoid conflict with other policies and objectives. Public Acceptability. Without public acceptance, successful implementa- tion of any management and disposition approach is unlikely. Gaining public acceptance will require attention to ES&H protection, as described above, and encouraging a decision-making process with genuine public participation, both local and national. Institutional Acceptability. Similarly, acceptance by the various institutions that must give their approval will be a critical factor in the success of any man- agement and disposition approach. Licensing in particular is likely to be a pacing factor in many cases, and clearly predictable difficulties in this regard could affect the choice of options. As with the public, early participation by the relevant institutions is essential. Other Policies and Objectives. Management and disposition of excess weapons plutonium should, as with other activities, be guided by the agree- ments, laws, regulations, and policies of the state carrying it out. Where a par- ticular approach would appear to contravene existing international agreements, for example, the committee considered this a major obstacle. Similarly, management and disposition of excess plutonium should ideally proceed in a manner supportive of the other policies of the state carrying it out. This includes, in particular, policies related to nonproliferation and nuclear fuel cycles. The committee does not believe, however, that promoting the future of civilian nuclear power-or the reverse should be considered a significant cri- terion for choice among options for disposition of weapons plutonium. That future depends on broader economic, political, and technical factors outside the

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CRITERIA FOR COMPARING OPTIONS 85 scope of this study. The committee also does not believe that whether pluto- nium disposition options would also have the potential to produce tritium should be a major criterion for deciding among them. (These subjects are ad- dressed in more detail in Chapter 6.)

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