SNF/HLW Disposal Strategy and Adaptive Staging

References:

• National Research Council, Board on Radioactive Waste Management (BRWM). 2002.  Principles and Operational Strategies for Staged Repository Systems: Progress Report. Washington, DC.
• National Research Council, Board on Radioactive Waste Management. 2001. Disposition of High-Level Waste and Spent Nuclear Fuel: The Continuing Societal and Technical Challenges. Washington, D.C.: National Academy Press.
• National Research Council, Board on Radioactive Waste Management. 1990. Rethinking High-Level Radioactive Waste Disposal. Washington, D.C.: National Academy Press.

Prediction, Repository Performance, and Waste Disposal Strategy

• An overview of the history of SNF and HLW waste management in the U.S. reveals a thoroughly pervasive technological optimism concerning the problems facing safe and socially acceptable disposal.  By the late 1970s, it was clear that there were many problems facing the waste disposal program and it would take a great deal of time, effort, and resources to overcome these problems.  While the federal government, through the DOE and the U.S. Congress, might have recognized that fact superficially, they still clung to a certain technical optimism that became evident in the policies and programs laid out for the siting, design, and eventual construction of a permanent waste disposal facility.  By setting rigid timelines, regulatory specifications, and limiting severely the site selection process, the federal government was assuming that any future roadblocks to the eventual construction of a repository could be overcome through technological means.  This assumption continues to be pervasive and is evident in the emphasis on performance assessments as a primary method for evaluating repository safety and communicating confidence in the proposed repository to the public.  The TSPA methodology is heavily technical in nature and to rely on the results from TSPA model is to put a great deal of faith in the underlying scientific data and the proposed repository processes and features and their conceptualizations.  Thus, the use of predictive science in the current manifestation of the waste disposal program, i.e. the Yucca Mountain TSPA, is closely tied to a particular waste disposal strategy.
  
  
• As the reliance on the TSPA for validation of repository safety has been criticized, so has the current waste disposal methodology.  In the three references cited above, the NRC reveals an implicit critique of the current methodology and suggests an alternative, which they term “adaptive staging” (NRC, 2002).
  
  
•  The NRC suggests that the biggest challenges to successful waste disposal programs are societal.  In contrast, the focus of the U.S. program has been on technical issues to the exclusion of social ones.  Thus, erosion of public trust has been and continues to be a central problem as there are few avenues for public discourse and input into decision making.  Without this trust, statements of the safety and need for permanent disposal of radioactive waste are summarily dismissed despite what might be credible and otherwise convincing supporting arguments.  Also, the linear and rigid policy framework employed in past waste disposal programs assumes that society has already collectively approved of the proposed disposal method.  In point of fact, this has not been the case and is evidenced by the vast public opposition to waste repositories as they move towards the construction phase.
  
  
• One factor contributing to public distrust has been the lack of transparency in the waste disposal and management program.  Waste disposal and storage options, site selections, and repository designs have been debated and decided upon in a relatively small community, which communicates to the public infrequently and through highly esoteric channels.  There is a paucity of institutional mechanisms for disseminating technical, policy relevant, and publicly consumable information concerning waste disposal decisions to appropriate communities.  In the past, the federal government has had problems communicating its reasons for particular policy decisions, and technical information used to support those decisions is rarely subjected to public peer-review.
  
  
• In addition, the fact that the scientific community and the public might have different ethical principles has been lost on the federal organizations responsible for drafting and pursuing publicly acceptably waste disposal policies.  For instance, much of the public views nuclear power and nuclear waste warily if not as a serious danger.  Projects associated with nuclear energy, such as geologic repositories, can take on this stigma, which makes them much harder to approve and complete.  Part of the reason behind this nuclear stigma is the government’s inability to effectively communicate risk and to stick to any single waste management policy.  Disagreement among technical experts and policy makers can foster the view that the issue in inherently insoluble.  Thus, non-technical factors may play a large role in the public’s perception of the risks involved in nuclear waste disposal, and scientists and decision makers must factor these judgments into their respective efforts.
  
  
• Another ethical concern is whether the site selection process is equitable.  Some argue that political factors bear too much weight in deciding which sites are suitable while others say that the decision cannot be made on purely technical grounds.  In either case, public involvement must be a central component in the site selection process and there must be institutional mechanisms for insuring some level of fairness.  The NWPA of 1982 attempted to create mechanisms to assure equity in site selection, but when the NWPA Amendments of 1987 limited study to Yucca Mountain, residents of Nevada cried foul as they felt that they had been left out of the site selection process.

Adaptive Staging

• In order to respond to the societal needs detailed above, the NRC recommends that radioactive waste disposal strategy be shifted to an “adaptive staging” methodology (NRC 2002).  Adaptive staging is defined as “a process where the development of geologic repository for high-level waste is divided into stages that are separated by explicit decision points.”  At each decision point, the results of scientific studies, site investigations, and computer models can be evaluated.  The prospect for repository safety can be determined and a final decision made on how to proceed to the next stage.  Thus, the goals and work of each stage are predicated upon the outcomes of previous stages.  This method allows the cost, schedule, and project design to be refined and improved as development proceeds.  Whereas a linear methodology works with a predetermined process towards a single goal, adaptive staging emphasizes flexible management towards a flexible goal.  The general aim of adaptive management is to increase repository safety and acceptability through “systematic incremental learning,” which allows the safety case to be refined and reevaluated at each step.
  
  
• The key advantages to adaptive management when compared with a linear approach are that it provides greater flexibility, transparency, integrity, and responsiveness to stakeholders.  A stepwise decision process also increases confidence is repository performance as continued scientific investigations can reduce some uncertainties at the same time societal uncertainties can be decreased as the public has an opportunity to become familiar with the development process.  Public involvement is increased as each decision point allows outside parties to contribute technical information and concerned citizens to voice their views.  In addition to increasing the mutual trust between stakeholders and federal organizations involved in repository development, adaptive staging can identify technical and political problems early on and compensate by reverting to previous stages.  This reversibility is not possible when most complicated projects move along a linear development process.  Reversibility can also boost confidence in repository design and construction as the negative consequences of making a technical mistake are reduced.