Document: NRC Regulatory Guide
Document ID: 8a2332d3-66ca-40af-84e1-507db8b26559
Document Type: regulatory_guide
Title: TRIAL - Acceptability of Probabilistic Risk Assessment Results for Non-Light Water Reactor Risk-Informed Activities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2123/ML21235A008.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.247
CFR Part: 
CFR Title: 

Content:
eptember 1993. 41. NRC, Management Directive 8.4, “Management of Facility-Specific Backfitting and Information Collection,” Washington, DC. (ADAMS Accession No. ML120159A460) RG 1.247, Appendix A, Page A-1 APPENDIX A NRC REGULATORY POSITION ON ASME/ANS RA-S-1.4-2021 Introduction The American Society of Mechanical Engineers (ASME) and the American Nuclear Society (ANS) have published ASME/ANS RA-S-1.4-2021, “Probabilistic Risk Assessment Standard for Advanced Non-Light Water Reactor Nuclear Power Plants” (Ref. 1). The standard gives the requirements1 for use of probabilistic risk assessments (PRAs) to support risk-informed decisions for non- light water reactor (NLWR) nuclear power plants (NPPs) and prescribes a method applying these requirements for specific applications. The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed ASME/ANS RA-S-1.4-2021 against the characteristics and attributes of an acceptable PRA as discussed in Regulatory Positions C.1 and C.2 of this regulatory guide (RG). The staff’s position on each requirement (referred to in the standard as a requirement, a high-level requirement, or a supporting requirement) in ASME/ANS RA-S-1.4-2021 is categorized as “no objection,” “no objection with clarification,” or “no objection subject to the following qualification.” These categories are defined as follows: • No objection. The staff has no objection to the requirement. • No objection with clarification. The staff has no objection to the requirement. However, certain requirements, as written, are either unclear or ambiguous, and therefore the staff has provided its understanding of these requirements. • No objection subject to the following qualification. The staff has a technical concern with the requirement and has provided a qualification to resolve the concern. ASME/ANS RA-S-1.4-2021 includes the following risk assessment technical requirements: • Plant Operating State Analysis • Initiating Event Analysis •