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2

Principal Findings and Conclusions

This chapter presents the committee's principal findings and conclusions regarding the disposition of high-level waste (HLW). 1 Each broad finding or conclusion is discussed briefly in this chapter, and further information that led the committee to its judgments is presented in Chapter 4, Chapter 5, Chapter 6, Chapter 7, Chapter 8 through Chapter 9. Recommendations derived from the committee's findings and conclusions are given in Chapter 3.

This chapter begins with the finding that the inventory of HLW is growing, which implies an increasing need to assure the safety and security of such materials. In many countries these materials are stored temporarily at or near the facility that produced them. While the committee believes that this practice is not generally sustainable in view of the growing inventory, 2 security concerns, and the decommissioning of many currently operating nuclear power reactors during the next several decades, the committee recognizes that radioactive waste management is a matter of national decision in each country. The committee also recognizes that for most countries there is no immediate urgency to implement a long-term alternative, since the present volume of radioactive waste is relatively small and manageable. Apart from continuing with current practices, there are only two available alternatives:


1 As discussed in Chapter 1 , for convenience in terminology the committee uses the term “high-level waste” to include reprocessing waste, spent nuclear fuel (SNF) if it is considered to be a waste, and other nuclear materials designated for disposition along with reprocessing waste and SNF.

2 About 25 countries have projected significantly increased inventories over the next 10 to 20 years. See Chapter 4.



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Page 20 2 Principal Findings and Conclusions This chapter presents the committee's principal findings and conclusions regarding the disposition of high-level waste (HLW). 1 Each broad finding or conclusion is discussed briefly in this chapter, and further information that led the committee to its judgments is presented in Chapter 4, Chapter 5, Chapter 6, Chapter 7, Chapter 8 through Chapter 9. Recommendations derived from the committee's findings and conclusions are given in Chapter 3. This chapter begins with the finding that the inventory of HLW is growing, which implies an increasing need to assure the safety and security of such materials. In many countries these materials are stored temporarily at or near the facility that produced them. While the committee believes that this practice is not generally sustainable in view of the growing inventory, 2 security concerns, and the decommissioning of many currently operating nuclear power reactors during the next several decades, the committee recognizes that radioactive waste management is a matter of national decision in each country. The committee also recognizes that for most countries there is no immediate urgency to implement a long-term alternative, since the present volume of radioactive waste is relatively small and manageable. Apart from continuing with current practices, there are only two available alternatives: 1 As discussed in Chapter 1 , for convenience in terminology the committee uses the term “high-level waste” to include reprocessing waste, spent nuclear fuel (SNF) if it is considered to be a waste, and other nuclear materials designated for disposition along with reprocessing waste and SNF. 2 About 25 countries have projected significantly increased inventories over the next 10 to 20 years. See Chapter 4.

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Page 21 1. implement new storage facilities, and 2. work toward emplacement in a repository (“geological disposition”), with the expectation that the repository eventually will be closed and sealed (“geological disposal”). See Sidebar 1.3. The advantages and drawbacks of both alternatives (and the likelihood of other options becoming available) must be evaluated as input for the necessary societal decisions. The benefits, costs, and risks associated with the two current options are of a radically different nature, so that a phased approach may enhance the benefits of both options. The long-term storage alternative can provide safety and security, as proven by more than 50 years of operation of such facilities. It also fulfills an ethical goal of keeping future options as open as possible. It can be extended to very long times in the future, provided that the storage is continuously monitored and maintained and periodically rebuilt. However, this option also faces societal challenges: efforts to site new storage facilities typically encounter public resistance, and storage requires a continuing commitment of resources. There is uncertainty that future societies will have the stability to maintain the strict institutional controls needed to prevent intentional misuse of nuclear materials or the will to continue to provide resources for the monitoring and maintenance needed for safety. Geological disposal, the approach recommended in previous National Research Council (NRC) reports (NRC, 1957, 1990) and by many other national and international scientific bodies, is the only available alternative that does not require ongoing control and resource expenditures by future generations. The science supporting this alternative has been developed by intensive work over the past 25 years. The view repeatedly expressed by a large fraction of the scientific and technical community is that geological disposal, correctly managed, is a safe approach to long-term management of HLW and that it best satisfies the ethical goal of minimizing burdens on future generations. Nevertheless, uncertainties remain, and some scientists feel that it is premature to commit fully to disposal. The biggest challenges to initiating geological disposition, however, are societal: there is a clear lack of public confidence and support in many countries for proceeding with siting and construction of geological repositories. Whether, how, and when to move toward geological disposition or disposal are societal decisions for each country, to be made following estimation of the uncertainties and risks associated with this option and with its alternatives. Given the technical and societal uncertainties, a stepwise process that allows for continuing improvement of scientific understanding is appropriate for decision making. A stepwise process, embedded within a flexible and adaptive management system, is also

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Page 22 appropriate to facilitate better communication with, and increased involvement of, the public to improve the basis for these societal decisions. International cooperation can help to achieve solutions to safe and secure disposition for all nations with responsibility for HLW. TODAY'S GROWING INVENTORY OF HLW REQUIRES ATTENTION BY NATIONAL DECISION MAKERS The present situation in the management of radioactive wastes worldwide is one in which—with some important, mainly defense-related, exceptions—safety and security are being achieved by storage on or near the surface. This safe and secure storage is feasible technically as long as adequate resources and political attention are devoted to it. However, inventories are increasing, and the duration of the hazard is so long that present and potential future problems must be anticipated, acknowledged, and addressed. The critical issues are the following: Public health and safety. Although the surface storage of wastes is satisfactory in most cases, the current storage conditions for some inventories do not meet national standards. National and international security. Fissile 3 materials can be misused by terrorists or by governments for clandestine development of nuclear weapons. Safeguarding the excess materials from weapons dismantlement is of critical importance. It also is important to safeguard the growing amount of separated reactor plutonium and the spent nuclear fuel (SNF). Ethics. Equity and fairness to current and future generations cannot be achieved unless positive steps are taken to manage the waste inventory in the long term. Nuclear energy. In many countries, consensus that radioactive wastes can be managed safely is one of the important prerequisites for continued or expanded use of nuclear power. Both the antinuclear and the pronuclear factions in society should have a direct interest in objectively clarifying whether safe and economic long-term management is feasible. In practice, opinions of both groups are colored by their views. Public trust and confidence. Many members of the public are concerned about the hazards of radioactive waste and about its linkage to potential nuclear weapons proliferation. They are yet to be convinced that scientists and national leaders can find a reliable solution for long-term isolation of radioactive wastes. 3 Fissile materials such as uranium-235 and plutonium-239 can undergo nuclear chain reactions that release large amounts of energy. They are basic materials for making nuclear weapons.

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Page 23 An international overview of the problems with HLW and other long-lived wastes begins with the observation that there are substantial existing inventories of these wastes. The inventories are growing because of the continuing use of nuclear power, the growing pace of disarmament, the increased emphasis on cleaning up historic defense-related “legacy” wastes, the decommissioning of nuclear power plants, and the application of nuclear technologies in medicine, industry, and research. The growing inventory presents the same or similar challenges (both technical and societal) in many countries, and there is much ongoing international cooperation. There are, however, significant differences among countries—including the management option chosen for SNF; the types, quantities, and current disposition methods for wastes; and the societal values prevailing—so that a universal solution cannot be expected. HLW presents potential safety and security problems. Safety refers to the risk of radiation doses to present or future generations because of inadequate isolation of radioactive waste from the biosphere. Most attention is paid in the technical analyses to potential releases of radionuclides from storage and disposal facilities, but other issues such as transportation safety also are relevant, and they are especially important to the public. Current practices, involving primarily storage of wastes at or near the production facilities, are regarded as safe by most national authorities. However, the growing inventory and the potential hazards involved suggest that this status quo cannot be sustained without a growth in risk, as new storage facilities are required. Moreover, there are also some urgent situations in which action is needed because adequate near- and long-term safety has not yet been achieved, particularly for defense-related wastes (e.g., U.S. Hanford Site tank wastes and Russian Northern Fleet and Mayak wastes). The leading security concern is the danger of misuse of fissile materials leading to the proliferation of nuclear explosive devices. Proliferation is a significant near-term threat. Reducing this threat motivates centralization of fissile materials and restricting access to plutonium and spent fuel (NAS, 1994; Carter and Pigford, 1999). There is growing concern that the risks of misuse are increasing, in particular, because the dismantling of nuclear weapons is producing large stocks of such materials. The threat posed by SNF is much less, although not insignificant (see Sidebar 1.1 ). The widespread practice of storing wastes at or near facilities where they were produced and the lack of progress toward an accepted long-term solution contradict intergenerational ethical objectives of fairness for both those who benefit from nuclear technologies and those affected by the waste. Achieving fair and equitable solutions to the waste problem has been, and will continue to be, a complex and difficult task. Neverthe-

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Page 24 less, developing equitable solutions is the responsibility of national decision makers. In many countries, the use of nuclear energy has met with increasing opposition over the past decades. The debate encompasses various aspects of nuclear power, including operational safety, economics, and waste management. The feasibility or infeasibility of safe long-term management has been an especially contentious feature of the debate. Demonstration of safe long-term waste disposition has been made a formal prerequisite for continued use of nuclear power in some countries. Such a prerequisite can lead to attempts by antinuclear factions to hinder work toward a waste disposal solution. It can also result in attempts by pronuclear factions to push a solution through on a shorter time scale than is technically necessary. Finally, and perhaps most importantly, a segment of the public has concerns and fears that radioactive wastes present a large and unmanageable threat. The challenge is therefore not just to identify options that are deemed suitable by technical experts for protecting the public, but also to assure that the decision processes and waste management technologies chosen have sufficiently broad public support. Support for any chosen technology will be difficult to achieve unless options for managing wastes can be presented, together with their consequences, and the public can participate in choosing among those options. For all of the above reasons, the committee concludes that the challenge of achieving safe and secure disposition of HLW in a manner that is technically sound and publicly acceptable requires attention by national decision makers. THE FEASIBLE OPTIONS ARE MONITORED STORAGE ON OR NEAR THE EARTH'S SURFACE AND GEOLOGICAL DISPOSITION The presently feasible options for HLW management are monitored storage on or near the earth's surface, or geological disposition in a mined repository that can become the site for geological disposal, if a decision is taken that the repository be filled, closed, and sealed. A stepwise process to move eventually from storage to disposal is described later in this chapter. Although decisions on managing radioactive waste are the prerogative of each individual country, the committee believes that the widespread current practice of temporary storage at or near the various sites of its production is not sustainable for the long term in view of growing waste inventories, security concerns, and aging nuclear facilities. If HLW is not managed properly, serious risks to public health and safety and to security will result.

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Page 25 Safe and secure surface storage is technically feasible as long as those responsible for it are willing and able to devote adequate resources and political attention to maintaining the facilities. Such storage has been shown to be safe and secure over several decades of past experience, and the technologies involved are well understood. HLW and SNF in storage facilities are readily monitored and retrieved. Current storage practices are intended for periods of about 50 to 100 years. There appears to be no technical reason why this storage could not be extended indefinitely, with continuing resources for upkeep and expansion as needed. Surface or near-surface storage is a long-term option provided society is willing to commit to ongoing active management to assure the integrity of the storage facilities. Surface facilities will always have a limited lifetime (e.g., decades to centuries). If storage facilities are to be used beyond their design lifetime, they will have to be rebuilt. This is technically feasible but obviously creates a financial and societal burden on future generations. Geological repositories will also require management, including monitoring and safeguarding, for many decades. The isolation of HLW from the environment in deep formations can help to assure security and safety by limiting human access. The initial capital costs of geological repositories are higher than those for surface storage facilities, although the final economic balance between options will depend strongly on financial assumptions. In choosing where to place the inventory of HLW over the next decades to several centuries, a society is confronted with decisions involving costs and risks, both long and short term, as well as how it might eventually progress toward a permanent, passively safe solution to waste management. Geological disposal is designed to provide passive safety and security. Storage also can provide ongoing safety and security, provided active management is continued. So can geological disposition, which is a reversible step toward geological disposal. There are no other available choices. All of the other known options either leave some HLW to be managed or cannot be implemented in the foreseeable future. Both surface storage and geological disposal involve uncertainties and risks. However, these uncertainties and risks differ in character in the two cases. For surface or near-surface storage, the committee perceives the major uncertainty to be the confidence that future societies will continue to monitor and maintain the storage facility. Will society keep its technical expertise indefinitely? Will it be willing or able to continue committing resources? In particular, will a future society that may no longer be using nuclear power still possess the expertise and the will to continue maintaining surface facilities? Can wars, terrorism, cataclysms, or negligence jeopardize the safety and security of storage? Because HLW re-

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Page 26 mains hazardous for a period of centuries to millennia, abandoned surface storage would pose a major risk to human health and safety. For geological disposal, uncertainties and risks have three prime sources: (1) Have the geological properties of the site been well identified, and is the future behavior of the system (consisting of both geological and engineered barriers) sufficiently well understood? (2) Can natural geological processes significantly jeopardize the behavior of the system and make it unsafe (e.g., new faulting, volcanic eruptions, or climate changes)? (3) Can unforeseen human actions in the future jeopardize the safety of the site? Selecting a disposition option should be done only when these different types of uncertainties have been compared and the preferred option has been chosen, based on an evaluation of the level of risk and public acceptance of each. The growing inventory in temporary storage raises equity and ethical issues that influence the choice of socially acceptable methods to assure safety and security. These issues include the following: the nature of our responsibilities to future generations (the need to protect future generations over very long periods, the desire to minimize burdens, and the wish to keep options open); how to redress inequities between the beneficiaries of the activities that produced the wastes and those who fear the risks associated with transport, storage, and disposition; who will bear the burden of proof for addressing uncertainties in proposed options and for making decisions to proceed with one option; and how to avoid the extremes of communicating greater certainty than actually exists and of exaggerating the importance of imperfections, gaps, or potential inaccuracies in the state of knowledge. Much of the societal concern is for the long term: what may happen after centuries or millennia. Here there are fundamental differences in views on whether geological disposition should be pursued now or deferred for a significant period of time. These differences arise primarily because of divergent judgments about the importance of the different types of uncertainties associated with storage and disposal (i.e., societal and technical uncertainties); and the priority allocated to conflicting ethical responsibilities to future generations (e.g., minimizing burdens versus maximizing choices). These fundamental differences were reflected also in the views of the committee members. They strongly colored the preferences with respect to storage versus the early pursuit of geological disposition and also

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Page 27 assessment of the needs for further research in the social and physical sciences. On the surface, monitoring and retrievability can easily be assured. In a deep repository, monitoring and retrievability also are possible and are made easier if one plans for a long period of retrievable emplacement as an interim step to disposal. Storage of HLW can provide safety and security. Nevertheless, the committee believes that it is not prudent to pursue only storage, without further development of the geological disposition option—unless a society believes it can credibly commit to permanent maintenance of its storage facilities. Storage leaves a potentially serious safety and security hazard on the surface; geological disposal is intended to do otherwise. Progress in geological disposition does not imply taking irreversible steps. The final decision to close and seal a geological repository will be made after decades of further observation and reflection within society, weighing the merits and uncertainties of continued storage versus geological disposition. GEOLOGICAL DISPOSAL REMAINS THE ONLY LONG-TERM SOLUTION AVAILABLE After four decades of study, geological disposal remains the only scientifically and technically credible long-term solution available to meet the need for safety without reliance on active management. Both safety and security are ongoing concerns for the existing HLW that is now stored on the earth's surface. The committee agrees that geological disposal is the only scientifically and technically credible long-term (i.e., many thousands of years) solution that is available to meet the need for safety without reliance on active management. Emplacement of the waste beneath the ocean or polar ice, which are technical variations of geological disposal that would also put the waste far below the earth's surface, are presently prohibited by international treaties. Disposal in space is not expected ever to be a practicable, safe technology. With regard to long-term safety, there do exist several actual or potential technological ways to modify the characteristics of the waste and thereby reduce future uncertainties. These include storing the waste for long enough to achieve some radioactive decay, chemical modifications to make waste more stable physically and chemically, and nuclear modification using partitioning and transmutation to reduce the quantity of long-lived radionuclides (see Chapter 7 ). All leave residual long-lived wastes, which require continued management or geological disposal. Thus, there is no available technical alternative to eventual geological disposal for permanently removing the waste from the human environment. The case is somewhat different for security. Technically feasible options for enhancing security do exist, such as burning fissionable materials in nuclear reactors. Therefore, the argument that geological disposal

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Page 28 is the only way to avoid the necessity for perpetual care and maintenance is not based directly on security concerns. However, geological disposal does offer obvious security benefits, because it would place fissile materials out of the reach of all but the most sophisticated potential builders of weapons. This is extremely important, because misuse of fissile materials that can be extracted from some types of radioactive waste may be the greatest hazard that radioactive waste presents to society. GEOLOGICAL DISPOSAL IS SCIENTIFICALLY AND TECHNICALLY SOUND, BUT IMPORTANT CHALLENGES REMAIN The scientific and technical basis for geological disposal is well advanced, but significant challenges remain for the characterization and performance assessment of specific sites. Nevertheless, the broad consensus in the scientific and technical community is that the knowledge database is adequate for supporting decisions in a step-by-step process leading toward geological disposal. The scientific and technical basis supporting the geological disposal concept has been built up over many years since the initial NRC report on the geological option was issued in 1957. This work has included fundamental studies on matrices for stabilizing the waste, other man-made barriers against release, and a variety of geological media in which a repository could be constructed. Research in specially constructed underground laboratories in several countries has included many interdisciplinary national and international collaborations. As in all scientific work, progress has been marked by surprises, new insights, and the recognition that for even the best-characterized sites, there always will be uncertainties about the long-term performance of the repository system. Providing convincing evidence that any repository assures long-term safety is a continuing technical challenge. To address this challenge, significant effort has been devoted worldwide over the past 25 years to the development of safety assessment methodologies and to achieving international consensus within the technical community on suitable approaches. During the 1980s and 1990s, the recognized need for a common understanding of the safety of repository concepts being developed in different countries encouraged international discussions on methodologies and efforts to involve the public in these discussions. There exists today an extensive literature documenting the techniques, applications, and results of safety assessments (NEA, 1997a, 2000c, 2000d). This knowledge base makes it feasible to provide guidance and advice on safety assessments for radioactive waste disposal and to characterize the natural features, events, and processes important for a well-designed repository at a well-selected and characterized site. As documented in the 1991 “Collective Opinion” of the Nuclear Energy

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Page 29 Agency (NEA) of the Organization for Economic Cooperation and Development, the International Atomic Energy Agency (IAEA), and the European Commission (NEA, 1991b), the feasibility of performing assessments of sufficient quality to support decisions on implementation of geological disposition is accepted by technical experts within the waste management community. In practice, there are many experts who feel confident enough about the state of current knowledge to advocate moving ahead now with repository implementation in correctly chosen locations. There are others who believe that a lot more research is needed before we even decide on the feasibility of permanent safe disposal. There are also those somewhere in the middle who support continuing the process leading to disposal, provided this remains stepwise and reversible. The consensus of the committee reflects the views of this middle group. The consensus that a cautious stepwise approach is the way to proceed was reached because those members who believe that the science and technology are already sufficiently mature recognize that the societal processes take time. The committee believes that differences in confidence among these groups are related, at least in part, to differences in their views of what is required to demonstrate repository safety, especially in the level of scientific understanding of repository system performance available today. In light of this experience, much of the scientific and technical work has included too few confidence-building measures such as peer review, formalized quality assurance, transparent documentation, large-scale demonstration, and—of great importance—development of processes to assure open discussion among all involved parties. Finally, the committee found that national programs generally have not developed scientifically sound and objectively balanced considerations of alternatives to geological disposal. Perceptions by the public and some members of the technical community of bias or predisposition toward the geological option probably have offset the credibility of much scientific effort. Recently, there has been an increasing awareness among those involved in technical and safety analyses that a broad perspective is needed to enhance confidence; narrow concentration on meeting specific regulations is recognized as insufficient (NEA, 2000b). The committee agrees with this judgment and concludes that simple, unsubstantiated reiteration of the technological conclusion that geological disposal is the preferred solution will be less constructive than assuring that the criteria for making decisions are made public and discussed. THE BIGGEST CHALLENGES ARE SOCIETAL Today the biggest challenges to waste disposition programs are societal in nature. Difficulties in achieving public support have been seriously underestimated in

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Page 30 the past, and opportunities to increase public involvement and gain public trust have been missed. Most countries have made major changes in their approach to waste disposition to address the recognized societal challenges. Such changes include initiating decision processes that maintain choice and that are open, transparent, and collaborative with independent scientists, critics, and the public. A complex of factors drives the high levels of public concern and lack of confidence in radioactive waste management programs apparent in most countries. These include the following: Unrecognized need. Many members of the public are not yet persuaded of the need for geological disposition of wastes. Meanwhile, the technical community has yet to convince the public of the long-term safety of the geological repository concept. Public perceptions of risk. Radioactive wastes are seen not only as significant dangers for health, safety, and the environment, but also as raising strong questions about the trustworthiness of institutions and their capacity to manage waste. Conventional safety analyses of repositories may not directly address the broader range of concerns that underlie public perceptions of risk. Value conflicts. Competing and conflicting values among different stakeholder groups (such as scientists, segments of the public, local communities, and national populations) make attaining any general consensus very difficult. Equity and ethical dilemmas. The management of HLW involves choices among competing and sometimes conflicting equity and ethical principles. Inherent conflicts arise between the ethical aims of minimizing burdens on future generations and maximizing their freedom of choice. Distrust. Low public trust in radioactive waste institutions and managers exists in many countries, influenced by a history of stop-and-start policies in this area, the failure to consult adequately in the past, and a more general decline of trust in social institutions across most industrialized countries. The issue of distrust is discussed in Chapter 5. The concept of risk based on the usual technical estimates of potential future radiation doses from repositories does not capture these broad factors driving public concerns. The concerns of the public are not likely to be changed solely by quantitative assessments, greater technical information, official reassurances, or proffered benefits to communities that host waste management facilities. Recognition of this reality has led to a shift in which the waste problem is no longer considered a purely scientific or technical task, but rather a sociotechnical challenge in which value choices are receiving new attention; institutional openness, transparency, and accountability are emphasized; and new means of engaging con-

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Page 31 cerned segments of the public are sought. This also applies to other technology-related challenges such as biotechnology and climate change or the siting of other facilities that segments of the public may deem undesirable, such as airports, highways, dams, and chemical plants. Social science research and understanding have been underemphasized in all national waste programs, as is evident when examining the highly technical activities and organizational structures of implementing and regulatory agencies. Sound research, analysis, and integration are indispensable in the social sciences as well as in the natural sciences and engineering. Today, significant gaps in knowledge exist concerning such central questions as why public confidence is apparently so low in the radioactive waste management area compared to other equally or even more risky human activities, how to best define and measure public confidence, how conflicts among ethical imperatives might be resolved, whether there are more effective means for engaging members of the public, and how institutions might best rebuild societal trust. Beyond this, compared to the physical sciences, there has been relatively little formalized social science expert overview and peer review of assumptions and institutional processes in the waste area. The committee notes that many national programs already have recognized the societal challenges and are restructuring accordingly. Changes to enhance public participation in all phases of waste disposition efforts have been initiated by national legislation, regulation, and, most importantly, waste management organizations themselves. The committee regards this change as a positive and essential step in the development of waste management options. WHETHER, WHEN, AND HOW TO MOVE TOWARD GEOLOGICAL DISPOSAL ARE SOCIETAL DECISIONS FOR EACH COUNTRY Each country must choose whether, when, and how to move toward geological disposal. In structuring its national radioactive waste management strategy, each country will make judgments about the following: the safety and security of ongoing or new storage and of geological disposal; the stability of its societal structures; the willingness to make a continuing commitment of resources for maintenance and monitoring; the need for public support and confidence; and the fairness and equity of alternative solutions. In any case, the decision process will be lengthy, and the time can be used to improve technical and societal approaches.

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Page 32 Because radioactive waste can be stored safely on the earth's surface, implementation of geological repositories is not necessary at any particular point in time. Some countries will prefer to accept the risks and costs associated with longer-term surface storage until, or unless, sufficient national public support for geological disposition develops. Other countries may encourage or require emplacement of waste in geological repositories in the near-term future, preferring to accept residual risks associated with potentially inadequate repository performance, including the financial risk that waste will have to be retrieved if future information shows repository performance to be inadequate. Accordingly, there is a large variation in the timing foreseen for countries pursuing geological disposal, even when the ultimate need for such disposal has been accepted. For example, the United States, Finland, and Sweden have plans for implementing geological repositories early in this century; countries such as Germany, Japan, Switzerland, and the United Kingdom are considering dates near the mid-century. The Netherlands measures the time for implementation as 100 or more years. In Canada, decisions about if and when to implement geological disposition are formally open. France passed a law specifying that no national decision on geological disposition versus continued surface storage should be made before 2006. No country plans to close and seal a geological repository in less than 50 years. Whatever choice is made, a number of years will pass before waste is emplaced in a central location, either a repository or new facilities to provide long-term storage. This period is appropriate to build the technical and social knowledge bases, the institutions, and the decision processes that will produce broad-based confidence in the solutions that eventually are chosen. Especially important will be efforts to consult, inform, and engage members of the public in weighing waste management options. It is important to consider how political decision makers can be presented with sufficient incentives to make them recognize that measures to advance toward long-term disposition of HLW and SNF should not be unnecessarily postponed or delayed. Value judgments will enter into decisions on how and when to move from surface storage to a geological repository; values and cultures in different countries may lead to different choices. In each country, there is a need for a broadly based, deliberative process that takes into account ethical issues (values of, and burdens on, present and future generations), public perceptions, and choices available to future generations. The process chosen also will depend on the state of scientific knowledge behind the geological disposal concept and any potential alternatives. Making a choice among options requires that the advantages, drawbacks, and uncertainties of each should be understood and appreciated fully. Few countries have prepared an objective, comprehensive comparison of alternatives.

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Page 33 A STEPWISE PROCESS IS APPROPRIATE FOR DECISION MAKING UNDER TECHNICAL AND SOCIETAL UNCERTAINTY Some—but not all—of today's uncertainties in predicting the future long-term behavior of a repository system can be reduced or eliminated by further research and development. However, for a very long time, “proof of safety” in the usual sense of these words will never be possible. This is also the case for many other technologies employed by today's civilization. For waste management, the long time scales give an added dimension, especially since the actions of future societies—particularly those in the distant future—cannot be predicted. Nevertheless, both our fundamental knowledge and our ways of dealing with uncertainty are advancing and will continue to do so during the course of a repository development program, which can last for many decades. A stepwise decision process can utilize this evolving knowledge to make sound decisions about repository siting, design, and operation. A stepwise decision process provides a means to improve knowledge and build confidence in repository development programs. Although a sound scientific methodology has been developed, it does not provide the capability to predict future repository behavior with the accuracy that would be required for complete assurance of containment over a thousand to a million years. How confident can one be in the results of these analyses? We must acknowledge and accept that neither a 100 percent level of safety nor 100 percent confidence in the reliability of the safety assessments is possible. This fact is true for every other comparable technical undertaking as well, but more attention has been devoted to the radioactive waste disposal issue than to most others. A commonly noted difficulty in quantifying the long-term safety of a repository is that there are no historical data with which to calibrate the methodology directly. This is, however, true for other technologies in which extremely low failure rates must be assessed. The uncertainties in waste disposal do present formidable challenges, especially in what has been called conceptual uncertainty. This is distinct from normal uncertainties in data or calculational methods. In all cases, what is really important is the consequence of uncertainties about the behavior of the repository over long times. For data and methodological uncertainties, the influence on overall performance can be assessed more readily than for conceptual uncertainty. The latter is concerned with inherently incomplete understanding of the physical and chemical phenomena that control site and repository behavior and of the future events that might affect repository performance such as climate, tectonics, and human behavior. In addition, uncertainties in projecting future human actions at a storage or disposal site grow with time to be larger than the technical uncertainties. Such societal uncertainties include:

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Page 34 the size and density of future populations, their living habits, their needs and values, their political stability, and their health and medical practices. Although much uncertainty can be reduced by further research, some uncertainty will not be resolvable. Approaches for dealing with some such uncertainties have been developed. For example, the impossibility of predicting future human behavior often is handled by the regulator's defining “stylized” scenarios that specify the choices to be used in a safety analysis (e.g., drilling frequencies, eating habits). This makes the regulatory process more practicable. Such steps taken by the regulator to enhance practicability do not relieve scientists of their responsibilities to consider all credible information in the safety analysis. Living with unresolvable uncertainties is inevitable in long-term radioactive waste management. This is also the case with other complex modern technologies. The issue is whether the level of knowledge is adequate to provide the necessary scientific input to the societal decision base at each stage in the stepwise development process. It will take, at a minimum, many decades before repositories are constructed, HLW is emplaced, and repositories are closed so that further retrieval, monitoring, or other active management essentially is terminated. The view of the committee is that scientifically justifiable decisions can be made today to take the next steps in developing a properly characterized repository site and to proceed further toward the geological disposal option. A properly characterized site is one whose present-day behavior is well understood and for which there is high confidence that its future behavior in conjunction with engineered barriers will provide acceptable isolation of the waste from the environment. In such cases, the committee believes that actions to continue along a stepwise repository development path are justified, as long as these actions are judged capable of providing acceptable safety and security, when the level of remaining uncertainty is considered. The committee has defined retrievable emplacement of HLW in a repository as geological disposition (see Sidebar 1.3 ). The decadal time scales required for repository development, combined with the robust safety characteristics of a well-designed repository, guarantee that moving forward in a stepwise fashion does not preclude parallel or subsequent development of other options. Hence, the important goal of being able to offer society a choice remains satisfied. In summary, stepwise development is the most promising approach for the following reasons: scientific and technical uncertainties are expected to diminish (although not disappear) as knowledge advances;

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Page 35 societal uncertainties can also be reduced to some extent by appropriate studies; and society is given a greater opportunity to become familiar with the issues, to participate in the decision-making process, and to build public confidence through the process. For this process to be successful, it is necessary that the public be given comprehensible information. SUCCESSFUL DECISION MAKING IS OPEN, TRANSPARENT, AND BROADLY PARTICIPATORY National waste disposition programs in democratic countries cannot hope to succeed today without a decision-making process that facilitates choices among competing societal goals and ethical considerations. Proceeding in a stepwise fashion and maintaining choice at various stages provide important means for building increased public confidence. Based on its discussions of the adverse experience with closed decision-making processes in the past, the committee believes that a program to select major components of the waste management system (“deciding what to do”), including sites, facility design, and technologies, is more likely to succeed if it results from an open, participatory, and stepwise process of deliberation and decision making. The goal of this process is to secure a high degree of public confidence concerning the fairness and appropriateness of the decisions, including support from the communities that will host the facilities. A key aspect increasingly acknowledged in recent years is that this goal is more likely to be achieved if waste management programs develop in stepwise fashion, with midcourse corrections at each stage as needed. This process involves a growing breadth of interested parties in decisions as it moves to higher stages of commitment to a specific technological approach and site. Such a process accumulates and builds public confidence in the emerging waste management system. Alternatives are identified throughout this process so that choices among options can be reviewed at each stage. Efforts are being promoted in many countries to establish a collaborative decision process that is open, transparent, and broadly participatory; addresses explicitly the values and ethical considerations that are implicit in alternative technical and policy choices; seeks more voluntary consent from communities that will host waste facilities; empowers a wider range of interested and affected members of the public; undertakes with interested scientists and segments of the public a full discussion of the need for safe waste disposition and the costs and risks of various alternatives, addresses the concerns of those in host

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Page 36 communities, and where appropriate, negotiates resolution of these concerns with them; provides compensation (in a moral and social as well as financial sense), as appropriate, for those in this and future generations who will bear burdens on behalf of others; and seeks to demonstrate, through its actions, that it is worthy of increased public trust, for example, through open discussion of the quality of information and by fulfilling its commitments. SUCCESSFUL PROGRAM MANAGEMENT IS FLEXIBLE AND ADAPTIVE A geological repository will be a first-of-its kind installation, with inherent uncertainties in its design, construction, and operation. Many of these uncertainties are equally important for long-term surface storage. Furthermore, we can, at best, make only educated guesses about the economic, societal, and political environment within which the waste management organization must operate during its active lifetime. A management system that is flexible, responsive to surprises, capable of midcourse corrections, and effective in its interaction with concerned segments of the public has the greatest possibility of success. In its 1990 report, Rethinking High-Level Radioactive Waste Disposal, the Board of Radioactive Waste Management of the U.S. National Research Council (NRC, 1990) summarized the issues constraining the choice of management systems for a process governing the long-term implementation of decisions. The issues raised were for disposal systems, but most are valid also for long-term storage concepts: Irreducible uncertainties exist in judging future risks of radioactive waste disposal or of long-term storage. An essential part of any management plan is how to operate with full public accountability as information about the risk changes with experience. Those involved in high-level waste management must avoid the trap of promising to reduce uncertainties to levels that are unattainable and recognize that the organization suffers most when it has understated risk or uncertainty. Consensus is difficult to reach in high-level waste management, given political controversy, conflicting value systems, and the variety of technical specialties involved in assessing system performance. A “perfect knowledge” approach is unrealistic, given inherent uncertainties, and runs the risk of encountering “show-stopping” problems and delays that could lead to a deterioration of public and scientific trust. Negotiation, persuasion, and compensation are fundamental parts of any program to manage radioactive wastes.

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Page 37 The management system should be flexible and responsive to surprises, that is, unanticipated societal or technical findings or events. Planning, constructing, and operating storage and disposal facilities, along with the necessary building of communication and trust with the public, will be a long process, extending over many decades. No geological repository for HLW has been constructed yet, so national programs will be pioneering a complex technological effort, and technical and societal surprises are inevitable. Stepwise program implementation (“doing what is decided” in a timely, effective manner) is appropriate for the management system. There are two interrelated reasons for this. One is the previously mentioned argument that the scientific and technical basis develops in stages, each giving increased confidence in the reliability of the concepts, data, specific designs, and system analyses or else showing where the scientific and technical basis is in need of further improvement. The other reason is that society needs time to become familiar with the developing technical systems and appears to favor discrete development stages, each of which is preferably reversible. Adaptive management is discussed in Chapter 8, and involving the public and technical communities in decision making is discussed in Chapter 5 and Chapter 6. INTERNATIONAL COOPERATION CAN HELP ACHIEVE NATIONAL SOLUTIONS International cooperation can bring benefits for all countries. International collaboration at the technical level already is extensive, but there are needs for better coordination at the strategic and political levels. Identical strategies will not result; national solutions will reflect different cultures, priorities, and legal systems. Cooperation especially can help less advantaged nations, for example, those with more limited financial means, small nuclear programs, or unfavorable geology. The cooperation can range from shared research programs to shared storage or disposal facilities offered by a host country to other nations. Sharing technology and facilities will reduce the cost burden for all of the cooperating nations and will greatly facilitate the establishment of internationally accepted standards. The management and eventual disposal of HLW present common challenges worldwide. Although how a country manages its waste is a national decision, the committee found that international cooperation is a significant asset to national programs. It is not necessary that every country tackle every problem independently or have national facilities for all waste management activities. In practice, cooperation in waste management among countries has been very active for many years. The nuclear fuel cycle already is international, with relatively few countries providing services by supplying uranium, enrichment services,

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Page 38 and fuel fabrication to a wide range of customer countries. There are established procedures and mechanisms for keeping appropriate oversight and control of international activities—particularly in the transport and safeguards areas. For long-term management of wastes, an international context is even more appropriate because the time scales in question exceed those for which the stability of any national border can be guaranteed. The IAEA Convention on the Safety of Spent Fuel and on the Safety of Radioactive Waste Management accordingly contains explicit requirements for adjacent countries (IAEA, 1997a). International cooperation originally concentrated on technical issues such as sharing methodological developments or data. Later, efforts were extended into the area of public information and communication—although this was more difficult because of cultural differences. The most urgent need for improvement today may be in the area of policy decisions. These need not be common to different national programs, but a common understanding of the justification for individual policy choices can improve communication and help make different approaches more explicable to the public in various countries. Progress in adopting a solution in one country serves as a positive example to other countries. There is no reason that all countries must be self-sufficient in all aspects of the nuclear fuel cycle. Many countries import uranium, and some share reprocessing services, as noted in Chapter 4 . There is international agreement that close cooperation in waste management is to be encouraged (IAEA, 2000b). Although multi-barrier repository concepts have been developed that could provide safety in well-chosen sites in most countries, not all countries utilizing nuclear power are equally suited for storing or disposing of HLW. Some countries are limited in area or have no suitable sites for repositories. Some small countries may not have sufficient waste quantities to justify a dedicated HLW repository. Some may not have the resources to develop repositories or facilities that can assure safe and secure ongoing storage. In any case, the establishment of many small repositories is not an ideal approach from either an economic or safeguards point of view. In the current climate of growing concern over potential increases in the risks of proliferation of weapons or of misuse of nuclear materials by terrorists, the importance of maintaining rigorous controls over fissile materials is increasing. Given the resources, the technical expertise and the geological and environmental prerequisites for implementing a geological repository, the committee believes that not every country with long-lived wastes will be able to implement a national repository. Even a surface storage facility could pose problems for some countries. Accordingly, the committee believes that some regionally or internationally shared surface storage facilities or repositories eventually will become a reality.

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Page 39 Although much is to be gained by international cooperation at all of the levels mentioned, a uniform approach to radioactive waste disposition is not expected. Differences in national waste management policies will result from the diversity of cultures, of specific problems, and of priorities. Some issues (e.g., those concerned with safeguarding fissile materials) demand a high degree of international conformity to agreed procedures. Other issues, such as the choice of method and the timing, can legitimately be treated differently in different nations.