Resolution of Key Technical Issues for High-Level Waste Disposal

In structuring its pre-licensing program for the proposed geologic respository for the disposal of high-level waste at Yucca Mountain, Nevada, the U.S. Nuclear Regulatory Commission (NRC) focused on the resolution of key technical issues (KTIs), as described in the following topics on this page:


Through the Nuclear Waste Policy Act of 1982 (NWPA) and the Nuclear Waste Policy Amendments Act of 1987, Congress directed the U.S. Department of Energy (DOE) to interact with the NRC in pre-licensing consultation regarding site characterization activities at Yucca Mountain, Nevada. In addition, the NWPA limited the amount of time the NRC would have to evaluate the license application submitted by DOE. Consequently, the purpose of this pre-licensing consultation process was to allow early resolution of the complex technical issues associated with the proposed geologic repository site, so that potential health and safety issues could be identified and receive the attention they deserved. In order to document the pre-licensing consultation, the NRC staff maintained a List and Status of KTIs for High-Level Waste.

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Process Description

The NRC staff closely monitored the resolution of KTIs by DOE to ensure that potential health and safety issues were identified and addressed. The staff also reviewed DOE's work (including analysis model reports) relevant to each issue, and conducted some independent technical work related to each issue.

The NRC documented the status of issue resolution, based on the results of its independent work and the review of the DOE work, in issue resolution status reports. In previous years, NRC reported on the status of issue resolution through individual status reports for each of the KTIs (see the List and Status of KTIs for High-Level Waste). Beginning in Fiscal Year 2001, the NRC staff decided to develop a single integrated issue resolution status report that would clearly and consistently reflect the interrelationships among the various KTI subissues and the overall resolution status. In addition, the integrated status report includes sections on pre-closure topics, performance confirmation, and quality assurance.

In addition to preparing the issue resolution status reports, NRC held meetings and technical exchanges with DOE to advance the issue resolution process. The NRC also conducted a series of meetings related to the KTIs, the NRC's sufficiency review, and the DOE site recommendation since August 2000. The objective of these meetings was to discuss and review the progress in resolving the KTIs. Meeting summaries and agreements between DOE and the NRC for each issue are documented for each meeting. The agreements describe the additional work that the DOE will complete to advance issue resolution.

Staff Evaluation of U.S. Department of Energy Analysis Model Reports, Process Controls, and Corrective Actions

An Evaluation Team of staff from NRC headquarters, NRC's Region IV office, and the Center for Nuclear Waste Regulatory Analyses (CNWRA) performed three targeted audits to evaluate the technical information in selected Analysis Model Reports and supporting information that were considered to be of high or medium significance to repository performance. The team also evaluated the processes for developing and controlling analysis model reports and the effectiveness of recent corrective actions in the areas of models, software, and data. On April 13, 2004, the NRC provided the team's evaluation findings to DOE, as follows:

Risk-Informing the Issue Resolution Process

On March 3, 2003, the NRC staff briefed the Commission on the status of the waste safety programs, performance, and planning in the Office of Nuclear Material Safety and Safeguards. Following the briefing, the Commission directed the staff to provide a report on the risk-significance ranking of the 293 KTI agreements. On June 5, 2003, the staff sent the report to the Commission, as follows:

The staff subsequently revised the Baseline of Risk Insights to reflect the structure of the Yucca Mountain Review Plan . The revised report described the development of the risk insights baseline, discussed the application of risk terminology in the NRC's high-level waste program, and incorporated quantitative analyses to support the risk insights. The staff rated the significance of the individual risk insights to assess the relative importance of staff activities. The risk insights were rated by considering the contribution to, or adverse effect on, the waste isolation capabilities of the repository system. On April 29, 2004, this revised report was sent to the Commission. The revised report subsequently served as a reference to help promote a clearer and more consistent staff position on the relative risk-significance of technical issues in the high-level waste program. In particular, the staff used the information documented in the revised report to help prioritize its pre-licensing activities, focus staff resources, and support risk-informed project management and decisionmaking in the high-level waste program. The staff also expects to use the revised report, together with the Yucca Mountain Review Plan and the integrated issue resolution status report, to conduct a risk-informed review of the license application that DOE submitted on June 3, 2008, requesting authorization to construct a high-level waste repository at Yucca Mountain.

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Current Status

All of the KTIs have been assigned the status "closed-pending."See the List and Status of KTIs for High-Level Waste for the definition of this term, as well as the integrated issue resolution status report.

Public Involvement

An agreement between DOE and NRC governed the interactions between the two agencies during the pre-licensing phase, and discussed the extent of public involvement permitted in these interagency meetings. See the High-Level Waste Disposal Meeting Archive page for meeting summaries and agreements.

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Page Last Reviewed/Updated Friday, August 27, 2021