Appendix A
Rethinking High-Level Radioactive Waste Disposal



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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management Appendix A Rethinking High-Level Radioactive Waste Disposal

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management This page in the original is blank.

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management Rethinking High-Level Radioactive Waste Disposal A Position Statement of the Board on Radioactive Waste Management Commission on Geosciences, Environment, and Resources National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1990

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of the appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Samuel O. Thief is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council. The material summarized in this report was the product of a July 1988 retreat sponsored by the Board on Radioactive Waste Management and was supported by the U.S. Department of Energy under Contract No. DE-AC01-86DP48039. Copies of this report are available in limited supply from: Board on Radioactive Waste Management National Research Council 2101 Constitution Avenue NW HA462 Washington DC 20418 Printed in the United States of America

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management BOARD ON RADIOACTIVE WASTE MANAGEMENT Current Members FRANK L. PARKER, Chairman, Vanderbilt University CLARENCE R. ALLEN, California Institute of Technology LYNDA L. BROTHERS, Davis Wright Tremaine PAUL BUSCH, Malcolm Pirnie, Inc. E. WILLIAM COLGLAZIER, University of Tennessee CHARLES FAIRHURST, Vice-Chairman, University of Minnesota ROBERT D. HATCHER, University of Tennessee* G. ROSS HEATH, University of Washington GEORGE M. HORNBERGER, University of Virginia RICHARD K. LESTER, Massachusetts Institute of Technology DAVID H. MARKS, Massachusetts Institute of Technology PERRY L. McCARTY, Stanford University ROGER O. McCLELLAN, Chemical Industry Institute of Toxicology FRED W. McLAFFERTY, Cornell University* D. KIRK NORDSTROM, U.S. Geological Survey* GLENN PAULSON, lit Center for Hazardous Waste Management CHRIS G. WHIPPLE, Clement International SUSAN D. WILTSHIRE, J.K. Associates Participating Former Members JOHN W. HEALY, Los Alamos National Laboratory (retired) KAI N. LEE, University of Washington EVA L. J. ROSINGER, Atomic Energy of Canada, Limited Current Staff PETER B. MYERS, Staff Director JOHN S. SIEG, Senior Staff Officer INA B. ALTERMAN, Senior Staff Officer GERALDINE J. GRUBE, Staff Officer ALEXANDRA N. BERNSTEIN, Research Associate JUDITH L. ESTEP, Administrative Secretary BETTY A. KING, Administrative Secretary PAUL B. PHELPS, Consulting Science Writer Participating Former Staff REMI B. LANGUM, Staff Officer JAN C. KRONENBURG, Administrative Assistant *    New members-Did not participate in report.

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management Invited Guest Participants PER-ERIC AHLSTROEM, Svensk Kaernbraensle-Hantering, Stockholm, Sweden ROBERT M. BERNERO, U.S. Nuclear Regulatory Commission, Washington, D.C. NEIL CHAPMAN, British Geological Survey, Nicker Hill, United Kingdom GHISLAIN DE MARSILY, Paris School of Mines, Paris, France CRITZ GEORGE, U.S. Department of Energy, Germantown, Maryland RICHARD J. GUIMOND, U.S. Environmental Protection Agency, Washington, D.C. RACHELLE HOLLANDER, National Science Foundation, Washington, D.C. THOMAS ISAACS, U.S. Department of Energy, Washington, D.C. ROGER E. KASPERSON, Clark University, Worcester, Massachusetts CHARLES E[D] KAY, U.S. Department of Energy, Washington, D.C. RONALD W. KIEHN, EG&G (retired), Idaho Falls, Idaho RICHARD MEEHAN, Expert Consultant on Scientific Evidence and Uncertainty, Palo Alto, California ROBERT MORGAN, U.S. Department of Energy (retired), Aiken, South Carolina TOENIS PAPP, Svensk Kaernbraensle-Hantering, Stockholm, Sweden JEROME RAVETZ, The University, Leeds, United Kingdom LEONARD SAYLES, Columbia University, New York, New York ANTHONY M. STARFIELD, University of Minnesota, Minneapolis, Minnesota

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management Contents     ABSTRACT   27     SUMMARY   29     Current U.S. Policy and Program   29     Scientific Consensus on Geological Isolation   30     Treatment of Uncertainty   31     Modeling of Geological Processes   32     Moral and Ethical Questions   34     An Alternative Approach   35     The Risk of Failing to Act   36     INTRODUCTION   38     The Origins and Purpose of This Document   38     High-Level Waste in Context   39     Radioactive Waste Management Policy   40     FINDINGS   41     The Limitations of Analysis   41     Overview   41     Uncertainty and Significant Risk   41     Perceptions of Risk   44     Moral and Value Issues   45     Overview   45     Three Issues of Equity   46     Five Issues of Policy   47     Modeling and Its Validity   49     Overview   49     Models and Modeling Problems   51     Appropriate Uses for Geophysical Models   51     Sources of Uncertainty in Geophysical Models   52     Modeling Limitation—An Example   53     Appropriate Objectives of Modeling   54     Using Models to Reduce Uncertainty   54     Supplements to Modeling   55     Implications for Program Management   56

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management     Strategic Planning   56     Overview   56     Policy Context   57     Alternative Management Strategies   58     The Elements of A More Flexible System   61     RECOMMENDATIONS   63     NOTES   65

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management ABSTRACT There is a worldwide scientific consensus that deep geological disposal, the approach being followed in the United States, is the best option for disposing of high-level radioactive waste (HLW). There is no scientific or technical reason to think that a satisfactory geological repository cannot be built. Nevertheless, the U.S. program, as conceived and implemented over the past decade, is unlikely to succeed. For reasons rooted in the public's concern over safety and in the implementing and regulatory agencies' need for political credibility, the U.S. waste disposal program is characterized by a high degree of inflexibility with respect to both schedule and technical specifications. The current approach, in which every step is mandated in detail in advance, does have several advantages: it facilitates rigorous oversight and technical auditing; its goals and standards are clear; it is designed to create a sense of confidence in the planning and operation of the repository; and if carried out according to specifications, it is robust in the face of administrative or legal challenge. This approach is poorly matched to the technical task at hand. It assumes that the properties and future behavior of a geological repository can be determined and specified with a very high degree of certainty. In reality, however, the inherent variability of the geological environment will necessitate frequent changes in the specifications, with resultant delays, frustration, and loss of public confidence. The current program is not sufficiently flexible or exploratory to accommodate such changes. The Board on Radioactive Waste Management is particularly concerned that geological models, and indeed scientific knowledge generally, have been inappropriately applied. Computer modeling techniques and geophysical analysis can and should have a key role in the assessment of long-term repository isolation. In the face of public concerns about safety, however, geophysical models are being asked to predict the detailed structure and behavior of sites over thousands of years. The Board believes that this is scientifically unsound and will lead to bad engineering practice. The United States appears to be the only country to have taken the approach of writing detailed regulations before all of the dam are in. As a result, the U.S. program is bound by requirements that may be impossible to meet. The Board believes, however, that enough has been learned to formulate an approach that can succeed. This alternative approach emphasizes flexibility:

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management time to assess performance and a willingness to respond to problems as they are found, remediation if things do not turn out as planned, and revision of the design and regulations if they are found to impede progress toward the health goal already defined as safe disposal. To succeed, however, this alternative approach will require significant changes in laws and regulations, as well as in program management.

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management SUMMARY Since 1955, the National Research Council (NRC) has been advising the U.S. government on technical matters related to the management of radioactive waste. Today, this advice is provided by the Board on Radioactive Waste Management (BRWM or ''the Board''), a permanent committee of the NRC. The conclusions presented in this position statement are the result of several years of discussions within the Board, whose members possess decades of professional experience in relevant scientific and technical fields. In July 1988, the Board convened a week-long study session in Santa Barbara, California, where experts from the United States and abroad joined BRWM in intensive discussions of current U.S. policies and programs for high-level radioactive waste (HLW) management. The group divided its deliberations into four categories: (1) the limitations of analysis; (2) moral and value issues; (3) modeling and its validity; and (4) strategic planning. A summary of the findings of these discussions, from which this position statement hasy been developed, follows the Summary. Current U.S. Policy and Program In the Nuclear Waste Policy Act of 1982 (NWPA), Congress assigned responsibility to the Department of Energy (DOE) for designing and eventually operating a deep geological repository for high-level radioactive waste. The repository must be licensed by the U.S. Nuclear Regulatory Commission (USNRC) and must meet radionuclide release limits, based on a generic repository, that would result in less than 1000 deaths in 10,000 years as specified in a Standard established by the Environmental Protection Agency (EPA) (40 CFR 191). The U.S. program is unique among those of all nations in its rigid schedule, in its insistence on defining in advance the technical requirements for every part of the multibarrier system, and in its major emphasis on the geological component of the barrier as detailed in 10 CFR 60. Because one is predicting the fate of the HLW into the distant future, the undertaking is necessarily full of uncertainties. In this sense the government's HLW program and its regulation may be a "scientific trap" for DOE and the U.S. public alike, encouraging the public to expect absolute certainty about the safety of the repository for 10,000 years and encouraging DOE program managers to pretend that they can provide it. For historical and institutional reasons, DOE managers tend to feel compelled to do things perfectly the first time, rather than to make changes in concept and design as unexpected geological features are encountered and

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management posits of radioactive elements and groundwater systems, in order to illuminate the behavior of the geologic environment. Professional Judgment. A second approach is to use the professional judgment of technical experts as an input to modeling in areas where there is uncertainty as to parameters, structures, or even future events. Such judgments, which may differ from those of DOE program managers and their staffs, should be incorporated early in the process. A model created by this process can redirect the DOE program substantially. It is important to bear in mind that all uses of technical information entail judgments of what is important and what is less so. If the technical community is to learn from the successes and failures of the DOE program, it is essential that these technical judgments be documented. Setting out the reasoning of DOE staff and of independent outside experts contributes to learning and builds credibility in the process even when the experts disagree with DOE staff and among themselves. Implications for Program Management The Board has concluded that geological models, and indeed scientific knowledge generally, are being inappropriately applied in the U.S. radioactive waste repository program. That misapplication prompts this Board to outline an alternative management strategy. The next section describes an alternative management approach that employs natural analogues and professional judgment in a program design that uses science appropriately in the search for a safe disposal system. Putting such an approach into effect, however, would require major changes in the way Congress, the regulatory agencies, and DOE conduct their business. Such changes will be difficult to achieve, but the Board has reluctantly concluded that nothing else will put to rest the problems that plague the national program today. Strategic Planning Overview There is no scientific reason to think that an acceptable HLW repository cannot be built and licensed. For historic and institutional reasons, however, DOE managers often feel compelled to "get it right the first time." This management strategy runs the risk of encountering "show-stopping" problems that may delay licensing and will certainly cause further deterioration of public and scientific trust. The alternative would be a more flexible, experimental strategy that embodies the following principles:

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management respond with conservative design changes as site attributes are discovered; use modeling to identify areas where more information is needed; and allow for remediation if things do not turn out as planned. Implicit in this approach is the need to revise both technical design and regulatory criteria as more information is discovered. This is difficult to achieve in a governmental structure that disperses authority among legislative and executive agencies and separates regulation from implementation. When presented with intense controversy, such an institutional arrangement breeds distrust among governmental units and the public. In that setting, partial remedies further entangle the procedural morass. More practically, however, DOE can enhance the credibility of the program and reduce the likelihood of late-stage surprises by (1) encouraging effective communication within its complex management structure; and (2) providing incentives for field personnel to identify and solve problems. DOE and the USNRC can also enhance credibility by encouraging periodic external reviews of the repository design, construction, and licensing requirements and associated processes. Policy Context The present U.S. approach to HLW disposal is increasingly vulnerable to being derailed by minor surprises. This vulnerability does not arise from a lack of talent or effort among the federal agencies and private contractors working on the program. Nor does the design or construction of the repository represent an unusually difficult technical undertaking. Instead, the program is at risk because it is following the wrong approach to implementation. The current predetermined process, in which every step is mandated in detail as in the more than 6,000-page "Site Characterization Plan,"15 is inappropriate. The current policy calls for a sequential process in which EPA and the USNRC first establish the criteria for safe disposal, and then DOE describes in detail what steps will be taken to move through site characterization, licensing, and operation of the facility. The result of this approach is that any late change, by any of the participating agencies, is taken as an admission of error. And late changes are bound to happen. One worker was killed and five injured in an HLW repository under construction in West Germany when a support ring failed unexpectedly. At the Waste Isolation Pilot Plant (WIPP) in New Mexico, the discovery of pockets of pressurized brine in formations below the repository level led to public outcries and a continual National Research Council review of the suitability of the site. The United States seems to be the only country that has taken the approach of writing detailed regulations before all of the data are in. Almost

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management all other countries have established limitations on the allowable levels of radiation dose to individuals or populations resulting from repository establishment–but have taken a "wait and see" approach on design, while collecting data that may be of use in setting design. The United States, on the other hand, seems to have felt that detailed regulations can be, in fact must be, written without regard to any particular geological setting or other circumstance. As a direct consequence, the U.S. HLW program is bound by requirements that may be impossible to meet, even though overall dose limits can be achieved. Alternative Management Strategies The preceding sections have shown that there are a number of unresolved issues in the U.S. radioactive waste disposal program, as well as (and in part because of) high levels of uncertainty and public unease about the performance of the repository. The Board's consideration of these subjects indicates that the proper response to distrust is greater openness in the process, and that the proper response to uncertainty is greater knowledge and flexibility, as well as redundancy of barriers to nuclide transport. The U.S. program will continue to face controversy until it adopts a management strategy based on these principles. The current approach to the design, construction, and licensing of the Nevada site is derived from the philosophy and procedures used for licensing nuclear power plants. The characteristics of the repository and its geological setting are carefully determined and specified as a basis for a complex set of calculations that describes the behavior of the system. This model is used to generate predictions of the migration of radioactive elements into the biosphere and analyzes the consequences of various events ("scenarios") that might affect the site over the next 10,000 years, in order to demonstrate that the repository site meets regulatory requirements (i.e., is "safe"). Based on the model and geologic studies of the site, the construction of the repository is specified in detail and then carried out under an aggressive quality assurance program, which is designed to withstand regulatory review and legal challenge. Within these requirements it is the geological setting that ensures isolation, not the engineered characteristics of the system; closure aims for complete entombment and discourages subsequent remediation. For all the reasons discussed above, a management process based on the regulation of nuclear power stations (a Region 3 type problem: see Figure 1) is inappropriate to the development of a waste repository. A well-documented alternative to this approach is being followed, to various degrees, by countries such as Canada and Sweden. The exploration and construction of a geological test facility and a low-level waste repository, respectively, follow a flexible path, allowing each step in the characterization

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management and design to draw on the information and understanding developed during the prior steps, and from prior experience with similar underground construction projects. During and subsequent to the closing of the repository, the emphasis will be on monitoring and on the ability to repair, in order to minimize the possibility that unplanned or unexpected events will compromise the integrity of the disposal system. Engineered modifications can be incorporated (e.g., in the waste containers or in the material used to backfill the repository) if the computer models suggest unacceptable or irreducible uncertainties in the performance of the unmodified containment system. The Canadian experience at their Underground Research Laboratory provides a good example. All of the major rock structures and groundwater conditions were defined from surface and borehole observations before shaft construction began. Detailed geological structure can never be totally determined from surface information, however, and the final details of the facility design were modified to take account of information gathered during shaft construction. What are the risks and benefits of the two approaches? The U.S. approach facilitates rigorous oversight and technical auditing. Its goals and standards are clear, and, if carried out according to specifications, this approach is robust in the face of administrative or legal challenge. It is designed to create a sense of confidence in the planning and operation of the repository, and it facilitates precise answers to specific technical questions. However, such an approach is not consistent with normal geologic or mining practice. It assumes that the properties of the geologic medium can be determined and specified in advance to a degree analogous to that required for man-made components, such as reinforcing rods, structural concrete, or pipes. In reality, geologic exploration and mine construction never proceed in this way. Most underground construction projects are more qualitative, using a "design (and improve the design) as you go" principle. New sections of drill core often reveal surprises that must be incorporated into the geologists' concept of the site, integrated with past experience, and used to modify the exploration plan or mine design. In a project where adherence to predetermined specifications is paramount, the inherent variability of the geologic environment will result in endless changes in the specifications, with resultant delays, frustration for field personnel, high overhead costs, and loss of public confidence in both the suitability of the site and the competence of the professionals working on the project. The second approach has more in common with research than with conventional engineering practice. This approach continually integrates new data into the expert judgments of geologists and engineers. It makes heavy use of natural analogues, such as undisturbed natural deposits of radioactive elements and groundwater systems, in order to illuminate the behavior of the geologic environment. It can immediately take advantage of favorable surprises and compensate for unfavorable ones. That this approach works

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management well is evidenced by the enormous number of underground construction projects in diverse geologic settings that have been completed successfully around the world. These projects were not designed to contain radioactive waste for thousands of years, but many of them faced technical problems of comparable magnitude, such as crossing active faults, sealing out massive groundwater flows, or stabilizing highly fractured and structurally weak rock masses. The second approach, with its reliance on continuous adaptation, would be much more difficult to document, audit, and defend before a licensing authority or court of law than is the more prescriptive approach. Some aspects of quality assurance can work well, such as document and sample control, the use of standard procedures and tools, and personnel qualifications. Other quality assurance techniques are likely to be contentious and may be impossible to implement in the same way they are implemented in nuclear power plants, including design control, instructions, procedures, drawings, inspections, and control of nonconforming items. An alternative is to use an aggressive and independent peer review system to appraise the decisions made and the competence of the technical personnel and managers responsible. The legal system is able to accept expert opinion as a basis for action or assessments of action, but one cannot predict whether a repository could ever be licensed in the face of the batteries of opposing "experts" who would inevitably be called on to assess a flexibly designed and constructed repository for HLW disposal. The debate will hinge in part on a clear understanding of the alternatives against which a proposed "solution" will be judged. By contrast, the EPA standards and USNRC regulations define requirements that, if met, form the basis for the presumption that the facility is "safe." Given the unhappy history of radioactive waste disposal in the United States, however, one very real and likely alternative is that nothing at all will be done. In judging disposal options, therefore, one should also adopt inaction or some other likely scenario as a default option, so that comparisons can be made and progress consistently assessed over time. The combination of a conservative engineering approach and designed-in maximum flexibility, to allow unanticipated problems to be corrected, should reassure both technical experts and concerned nonexperts. The barrier is not logical but institutional, and the prescriptive approach in the U.S. program is dictated by a governmental structure that separates regulation from implementation. Within the present program, for example, "quality assurance" has become the bête noire of frustrated field personnel, who are trying to work within a system that is hostile to surprises in a world that is full of them. Because almost any geologic phenomenon has more than one possible cause, flexibility (including the recognition that uncertainty is inevitable and must be accommodated) is more likely to lead to the design and construction of a

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management safe repository system than are rigid, predetermined protocols. In employing and evaluating such an adaptive approach to construction, emphasis focuses on those decisions that have irreversible or noncorrectable consequences on disposal, rather than on the myriad small adjustments that do not affect the basic flexibility and robustness of a repository. The Elements of a More Flexible System In a program governed by this alternative approach, change would not be seen as an admission of error; the system would be receptive and responsive to a continuing stream of information from site characterization. The main actors would reduce their reliance on detailed preplanning during initial site characterization, making it possible to debug the preliminary design during rather than before characterization.16 But the necessary conditions of the system are flexibility and resiliency—flexibility to respond rapidly to ongoing findings in the geology, geohydrology, and geochemistry (within broad constraints); and resiliency to continuously adjust the performance assessment to reflect new information, especially where such information indicates possible precursors of substantial increases in risk. These qualities could be developed through the following steps: Iterative performance assessment. The basic approach outlined here would start with a simplified performance assessment, based on known data and methods of interpretation. Given the inherent uncertainties and technical difficulties of the process, the present system may well expend large efforts on small risks, and vice versa. An iterative approach, on the other hand, could allow characterization efforts to give priority to major uncertainties and risks, while there is still time and money left to do something about them. As in probabilistic risk assessment, analysis focuses on efforts to reduce the important risks and uncertainties. In this case, that means acquiring information on the design features and licensing criteria that are most likely to determine whether the site is suitable or should be abandoned. Fixing problems vs. anticipating problems. The underlying concept of the present, anticipatory U.S. management strategy is "Get it right the first time." One result is a 6,300-page "Site Characterization Plan" for Yucca Mountain. For the reasons described above, however, a process based on getting all of the needed measurements and analysis on the first pass, with acceptably high quality, is not likely to succeed. The geological environment will always produce surprises, like the pockets of pressurized brine at WIPP. No matter what technical approach is initially adopted, the design can be improved by matching it with specific features of the site. Experiments are now being conducted at WIPP with backfill material and other engineered barriers that were not part of the original design. These

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management are being tried as ways to make the disposal system as a whole robust in the face of newly discovered uncertainties in the geology. Define the problem broadly. As characterization proceeds, especially if it is done without the guidance of iterative performance assessment, DOE may eventually find it difficult or impossible to meet some of the criteria set by the USNRC and/or EPA. This will not mean that Yucca Mountain is unsuitable for a repository—the problem could be with the detailed criteria. This is no reason to arbitrarily abandon the release limits—it is the more detailed requirements that may need to be reconsidered, since they ultimately affect the release limits and the imputed dose. However, one should not take EPA's release standards or the USNRC's detailed licensing requirements as immutable constraints. They are roadmarkers to, and surrogates for, dose limits. Although the EPA standards and the USNRC regulations recognize and accept a certain level of uncertainty, the discussion to date of the application of these standards and regulations does not warrant confidence in the acceptance of uncertainty in licensing procedures. Some process is needed in order to determine whether DOE's inability to meet a particular requirement is due to a disqualifying deficiency in the site or to an unreasonable regulatory demand, one that is unlikely to be met at any site and is unnecessary to protect public health. And to the extent that regulatory criteria can be corrected earlier instead of later in the process, they are more likely to be perceived as technical adjustments rather than as a diminution of public safety. Given the history of U.S. efforts to dispose of radioactive waste, current plans for the program have little chance of progressing without major modification in the 20 years or more that will be required to get a repository into operation.

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management RECOMMENDATIONS The Board's conclusions are explicit or implicit throughout this document, as are many of the actions it would recommend to the various players. These recommendations are summarized below. Congress should reconsider the rigid, inflexible schedule embodied in NWPA and the 1987 amendments. It may be appropriate to delay the licensing application, or even the scheduled opening of the repository, until more of the uncertainties can be resolved. The Secretary of Energy's recent announcement of a more realistic schedule, with the repository opening in 2010 rather than 2003, is a welcome step. The Environmental Protection Agency, during its revision of the remanded 40 CFR Part 191, should reconsider the detailed performance standards to be met by the repository, to determine how they affect the level of health risks that will be considered acceptable. In addition, EPA should reexamine the use of quantitative probabilistic release criteria in the standard and examine what will constitute a reasonable: level of assurance (i.e., by what combination of methods and strategies can DOE demonstrate that those standards will be met?). All other countries use only a dose requirement. In setting regulatory standards and licensing requirements, the EPA should consider using only dose requirements.  The U.S. Nuclear Regulatory Commission, likewise, should reconsider the detailed licensing requirements for the repository. For example: What level of statistical or modeling evidence is really necessary, obtainable, or even feasible? To what extent is it necessary to prescribe engineering design, rather than allowing alternatives that accomplish the same goal? What can be done to accommodate design changes necessitated by surprises during construction? What new strategies (e.g., engineered features like copper containers) might be allowed or encouraged as events dictate?  The Department of Energy, for its part, should continue and also expand its current efforts to become a more responsive player in these regulatory issues. The following activities should be included: publicly negotiated prelicensing agreements with the USNRC on how to deal with the high levels of uncertainty arising from numerical predictions of repository performance;

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management publicly negotiated prelicensing agreements with the USNRC on improved strategies for performance assessment; active negotiations with EPA and the USNRC on the real goals and precise definitions of their standards and requirements; an extramural grant program, in cooperation with the National Science Foundation, for the development of improved modeling methodology, in combination with training programs and public education efforts; expanded use of expert scientists from outside the program to review and critique detailed aspects and to provide additional professional judgment; greatly expanded risk communication efforts, aimed at reaching appropriate and achievable goals acceptable to the U.S. public; meaningful dialogue with state and local governments, Indian tribes, environmental public interest groups, and other interested organizations. The Department of Energy should make greater use of conservative engineering design instead of using unproven engineering design based on scientific principles. The Department of Energy should participate more actively in international studies and forums, such as those sponsored by the International Atomic Energy Agency, the Nuclear Energy Agency, and the Commission of European Communities, and should subject its plans and procedures to international scientific review, as Sweden, Switzerland, and the United Kingdom have already done.  Although geologic disposal has been the national policy for many years, and the Board believes it to be feasible, contingency planning for other sites and options (for example Subseabed Disposal of spent fuel and high-level radioactive waste) should be pursued. The nation, the Congress, the federal government, utilities, and the nuclear industry should recognize the importance of contingency planning in the event that some issue should make it impossible to license a geologic repository.

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management NOTES 1. Report on the Review of Proposed Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High Level and Transuranic Radioactive Wastes (40 CFR 191) by the High-Level Radioactive Waste Disposal Subcommittee of the Science Advisory Board, U.S. Environmental Protection Agency, (January 1984) pp. 10–14. 2. May 10, 1983 letter from John G. Davis to EPA transmitting USNRC staff comments on the proposed High-Level Waste Standard (40CFR 191). 3. Roger E. Kasperson and Samuel Ratick, ''Assessing the State/Nation Distributional Equity Issues Associated with the Proposed Yucca Mountain Repository: A Conceptual Approach,'' a technical report prepared for the Nevada Nuclear Waste Project Office and Mountain West Research, Inc., (June 1988) pp. 1–22. 4. Each generation must not only preserve the gains of culture and civilization, and maintain intact those just institutions that have been established, but it must also put aside in each period of time a suitable amount of real capital accumulation." J. Rawls, "A Theory of Justice," (Harvard University Press, 1971) p. 284. 5. Sheldon J. Reaven, "How Sure is Sure Enough," Department of Technology and Society, State University of New York at Stony Brook, draft paper prepared for the project referenced in Colglazier (note 7), (1988). 6. Sheila Jasanoff, draft chapter "Acceptable Evidence in a Pluralistic Society," in Acceptable Evidence: Science and Values in Hazard Management , Deborah G. Mayo and Rachelle Hollander, eds. (Oxford University Press, 1990, in press). 7. This project, supported by the National Science Foundation, included the following researchers: E. William Colglazier, David Dungan, and Mary English of the University of Tennessee; Sheldon Reaven of the State University of New York at Stony Brook; and John Stucker of Carter Goble Associates. Some of the project papers published to date by Colglazier include: "Evidential, Ethical, and Policy Disputes: Admissible Evidence in Radioactive Waste Management," in Acceptable Evidence: Science and Values in Hazard Management, Deborah G. Mayo and Rachelle Hollander, eds. (Oxford University Press, 1990, in press); "The Relation of Equity Issues to Risk Perceptions and Socioeconomic Impacts of a High Level Waste Repository," Waste Management '89, proceedings of the Waste Management '89 Conference (University of Arizona, 1989); "The Policy Conflicts in the Siting of Nuclear Waste Repositories," Annual Review of Energy, Vol. 13 (1988), pp. 317–357; and "Value Issues and Stakeholders' Views in Radioactive Waste Management," Waste Management '87, proceedings of the Waste Management '87 Conference (University of Arizona, 1987). 8. Anthony M. Starfield and P. A. Cundall, "Towards a Methodology for Rock Mechanics Modeling," International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, special issue, C. Fairhurst, ed., Vol. 25, No. 3 (June 1988) pp. 99–106. 9. C.S. Holling, ed., Adaptive Environmental Assessment and Management , (Wiley, Chichester, 1978).

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Radioactive Waste Repository Licensing: Synopsis of a Symposium sponsored by the Board on Radioactive Waste Management 10. L.F. Konikow, "Predictive Accuracy of a Ground-Water Model: Lessons from a Post Audit," Ground Water, Vol. 24, No. 2 (March–April 1986) pp. 173–184. 11. R.A. Freeze, G. de Marsily, et al., "Some Uncertainties About Uncertainty," paper presented at the DOE/AECL symposium on the use of geostatistics in nuclear waste disposal, San Francisco (September 1987). 12. George M. Hornberger and R. C. Spear, "An Approach to the Preliminary Analysis of Environmental Systems," Journal of Environmental Management , Vol. 12 (1981), pp. 7–18; J. N. R. Jeffers, "The Challenge of Modern Mathematics to the Ecologist," in Mathematical Models in Ecology, J. N. R. Jeffers, ed. (Blackwell Scientific, Oxford, 1972). 13. Freeze, de Marsily, et al., op. cit. 14. G. M. Hornberger, B. J. Cosby, and J. N. Galloway, "Modeling the Effects of Acid Deposition: Uncertainty and Spatial Variability in Estimations of Long-Term Sulfate Dynamics of a Region," Water Resources Research, Vol. 22, No. 8 (August 1986) pp. 1293–1302. 15. Department of Energy, Office of Civilian Radioactive Waste Management, Site Characterization Plan: Yucca Mountain Site, Nevada Research and Development Area, Nevada, DOE/RW-0199 (U.S. Department of Energy, Oak Ridge, TN, December 1988). 16. C.G. Whipple, "Reinventing Radioactive Waste Management: Why 'Getting It Right the First Time' Won't Work," Waste Management '89 , proceedings of the Waste Management '89 Conference (University of Arizona, 1989).