Document: NUREG-0800
Document ID: 0d034ca5-ee9b-43ca-a6d6-b08e537d605b
Document Type: srp
Title: Determining the Technical Adequacy of Probabilistic Risk
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0625/ML062510220.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.1
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e with the relevant documents with the exceptions and clarifications found in the Appendices to RG 1.200. The reviewer is to focus on the elements that have deviations from, or discrepancies with, the technical requirements of the endorsed documents. The reviewer may make a judgment that the deviation or discrepancy leads to an acceptable equivalent to the requirements of the endorsed documents. Alternatively, the reviewer may determine that the issue has been addressed adequately if the licensee has given reasons as to why the discrepancies are not important, or provided a demonstration that the discrepancy has no significant impact on the results used in the decision. III.2.3 Assessment of Engineering Analyses, Assumptions, and Approximations Since the standards and industry PRA programs are not (or are not expected to be) prescriptive, there is some freedom on how to model certain issues in the PRA, so that different analysts may make different assumptions regarding these issues, yet the issues still meet the requirements of the standard or have been accepted by the peer review. The choice of a specific assumption or a particular approximation may, however, influence the results of the PRA. The NRC staff needs to be confident that the conclusions drawn from the PRA are not invalidated by the use of specific assumptions. This is addressed primarily in the application-specific assessment through the use of sensitivity analyses. The identification of the important assumptions is addressed in the application-specific regulatory guides and SRP chapters. However, the staff should review the licensee’s basis for those assumptions and their justification, taking into account the peer reviewers’ assessment. The staff’s focus should be on determining that the assumptions have been characterized appropriately so that there is sufficient information to conclude that the sensitivity studies performed to test the robustness of the conclusions are reasonable with respect