Disposal of high-level nuclear waste requires a U. S. Nuclear Regulatory Commission license. Part 63 under Title 10 of the U. S. Code of Federal Regulations ("Disposal of High-Level Radioactive Wastes in a Proposed Geologic Repository at Yucca Mountain, Nevada") is the governing rule. U. S. Nuclear Regulatory Commission authority to regulate a high-level waste repository comes from the Atomic Energy Act of 1954, as amended; the Energy Reorganization Act of 1974, as amended; and the Nuclear Waste Policy Act of 1982, as amended. The Yucca Mountain Review Plan is guidance to the staff for review of any license application from the U. S. Department of Energy for a geologic repository for disposal of high-level radioactive waste. The U. S. Nuclear Regulatory Commission has directed the staff to carry out risk-informed and performance-based regulatory programs. 10 CFR Part 63 is risk-informed, performance-based, because risk of health effects to the reasonably maximally exposed individual is the basis for its performance objectives. 10 CFR Part 63 also requires protection of ground water by limiting the radioactivity in a representative volume of ground water and an assessment of repository performance under conditions of human intrusion. The U. S. Nuclear Regulatory Commission will base its licensing decision on whether the U. S. Department of Energy has demonstrated compliance with the performance objectives. Therefore, the Yucca Mountain Review Plan is risk-informed, performance-based.
The principal purpose of the Yucca Mountain Review Plan is to ensure the quality and uniformity of staff licensing reviews. Yucca Mountain Review Plan sections present the areas of review, review methods, acceptance criteria, evaluation findings, and references the staff will use for its review. There are sections for an acceptance review, reviews of general information, preclosure repository safety, postclosure repository safety, the research and development program to resolve safety questions, the performance confirmation program, and administrative and programmatic requirements. A summary of the risk-informed, performance-based foundation for each section follows.
An acceptance review is the first screening of the U. S. Department of Energy license application. The application must provide enough information to demonstrate compliance with the regulations. The reviewer will evaluate whether the information is sufficient to support a detailed review, and will assess the schedule for any later U. S. Nuclear Regulatory Commission milestones. The acceptance review does not determine the technical adequacy of the submitted information. U. S. Nuclear Regulatory Commission staff will send the results of the acceptance review, with a projected schedule for the rest of the review, to the U. S. Department of Energy within 90 days of receiving the license application. If the license application fails this minimum standard, the staff will tell the U. S. Department of Energy the application will not support a detailed technical review, and will recommend specific corrective action.
The general information material provides a broad overview of the U. S. Department of Energy engineering design concept for the repository and allows the U. S. Department of Energy to demonstrate its understanding of which aspects of the Yucca Mountain site and its environs influence repository design and performance. More detailed technical descriptions are in the Safety Analysis Report sections of the license application. Notable exceptions are the "Physical Protection Plan" and "Material Control and Accountability" sections. The extent to which the general information incorporates risk-informed, performance-based principles varies.
The preclosure safety analysis evaluates compliance with performance objectives to limit levels of doses to workers and the public considering acceptable risk levels. 10 CFR Part 63 requires the U. S. Department of Energy to demonstrate compliance using a preclosure safety analysis. A preclosure safety analysis systematically examines the site, the design, the potential hazards, and initiating events and their consequences, and the potential dose consequences to workers and the public. The preclosure safety analysis considers the probabilities and uncertainties associated with potential hazards. The preclosure review will focus on the U. S. Department of Energy demonstration that the repository design, construction, and operation will meet the performance objectives (exposure limits.) The staff will apply resources proportionately to review high-risk significant systems, structures and components important to safety.
10 CFR Part 63 requires the U. S. Department of Energy to conduct a performance assessment to demonstrate compliance with the postclosure performance objectives. A performance assessment systematically analyzes what can happen, the likelihood, and the consequences. The staff will use risk information to focus on those items most important to performance. The staff will examine the U. S. Department of Energy identification of natural and engineered barriers important to waste isolation. The staff will use risk insights from previous performance assessments for the Yucca Mountain site, detailed process-level modeling efforts, laboratory and field experiments, and natural analog studies. The staff will then evaluate the U. S. Department of Energy scenario analysis. The scenario analysis must consider the risk information from identified barriers and include the identification and screening of features, events, and process and construction scenarios from the retained features, events, and processes of the Yucca Mountain site. Finally, the performance assessment review will examine information of 14 model abstractions. The abstractions arose from engineered, geosphere, and biosphere subsystems shown to be most important to performance, based on previous performance assessments, knowledge of site characteristics, and repository design. Since it is unlikely each of the model abstractions will have equal risk significance, the staff will focus on those with the greatest risk to repository performance. For the postclosure period, "important to performance" means important to meeting the radiation exposure performance objective. The risk of radiation health effects is the basis for the radiation exposure limit. The postclosure performance objectives also protect ground water by limiting the radioactivity in a representative volume of ground water. Postclosure performance objectives also require an assessment of performance under conditions of human intrusion.
The review of the research and development program for resolving safety questions applies to systems, structures, and components important to safety, and engineered and natural barriers important to waste isolation. The program identifies, describes, and discusses safety features or components that require further information to confirm the adequacy of design. This will be a risk-informed review, because it focuses on those items most important to safety or waste isolation.
The review of the performance confirmation program examines the program of tests, experiments, and analyses the U. S. Department of Energy will conduct to evaluate the adequacy of the information used to demonstrate compliance with the performance objectives in 10 CFR Part 63. A performance confirmation program is unique and results from uncertainties in estimating performance over thousands of years. The section is risk-informed, performance-based because it focuses on parameters and engineered and natural barriers important to performance.
10 CFR Part 63 provides no performance objectives for the administrative and programmatic sections of the Yucca Mountain Review Plan. Existing regulatory programs are the basis for acceptance criteria and review methods in this section. The staff considered the expected operations and associates risks, while taking advantage of opportunities to limit prescriptive requirements. The quality assurance section of the Yucca Mountain Review Plan contains review methods and acceptance criteria to support a review of either graded or nongraged program. The staff will conduct a risk-informed review for a graded quality assurance program.