Document: NUREG-0800
Document ID: 2dc4ec7e-926d-4aba-8a72-19deee03b06d
Document Type: srp
Title: DETERMINING THE TECHNICAL ADEQUACY OF PROBABILISTIC RISK
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0717/ML071700657.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.1
CFR Part: 
CFR Title: 

Content:
risk assessment (PRA) standards have been developed by the American Society of Mechanical Engineers (ASME) and American Nuclear Society (ANS). On April 5, 2002, ASME issued a standard (ASME RA-S-2002) for a full-power, internal events (excluding fire) Level 1 and a limited Level 2 PRA. Addenda A and B to the Standard were issued in December, 2003 and December, 2005 respectively. In December 2003, ANS issued a standard for external events (ANSI/ANS-58.21-2003). ANS is developing Level 1 and limited Level 2 PRA standards for internal fire, the low power and shutdown modes of operation, and Level 2 and Level 3 PRAs. In parallel, reactor owners' groups developed a PRA peer review program documented in NEI-00-02, "Probabilistic Risk Assessment Peer Review Process Guidance," Revision A3. Over the course of several years, this peer review program was applied at all the U.S. nuclear power plants. For all but one of the plants, the criteria used to assess the technical adequacy of the PRAs had been developed to some extent independently of the development of the ASME PRA standard. Therefore, the results of the peer review could not be used directly to assess whether the PRA was in conformance with the ASME PRA standard. On August 16, 2002, NEI submitted draft industry guidance for self-assessments (Letter A. Pietrangelo to S. Newberry) to address the use of industry peer review results in demonstrating conformance with the ASME PRA standard. This additional guidance contains: 1. Self-assessment guidance document 2. Appendix 1, actions for industry self assessment 3. Appendix 2, industry peer review subtier criteria. Concerns regarding PRA quality and the standards development effort were discussed during the March 31, 2000, Commission briefing on the Risk-Informed Regulation Implementation Plan. The Commission, in their April 18, 2000, Staff Requirements Memorandum (SRM) on that briefing, indicated that the staff "should provide its recommendations to the Commission for