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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Content:
technical adequacy. Implementation of RG 1.200 should obviate the need for staff review of the base PRA for the risk scope for which a standard and a corresponding appendix to RG 1.200 exist. A staff review of PRAs the risk scope significant to the decision for which no standard has been endorsed in RG 1,200 will be necessary to the extent needed to support the decision. However, even for the risk scope addressed by standards, the staff may, under certain circumstances, decide to perform an audit to verify the technical adequacy of the PRA. An audit may be initiated for a number of reasons, some of which are identified below: • Lack of evidence that the self-assessment actions that are most relevant to the application have been adequately performed. • Concerns about the resolution of peer review findings associated with the technical requirements that are most relevant to the application. • Contributors (e.g., accident sequences, cutsets, operator actions) to the results that differ from those seen at other, similar plants, and for which no plant specific design features can be identified that would explain the differences. • Results that seem to be counterintuitive, e.g., a decrease in CDF when equipment is taken out of service. • Estimates of CDF or LERF that differ significantly from those in prior submittals from the same licensee, without a sufficient explanation. It is expected that a licensee using a PRA standard or standards, and/or the industry peer review process has taken account of the exceptions and clarifications found in the appendices of 8 Regulatory Guide 1.200 and has documented the comparison with the relevant documents as endorsed. The reviewer should determine that the peer review and self-assessment have been performed in conformance 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