Document: NRC Regulatory Guide
Document ID: 82659041-98b0-4721-b25d-c4fb2ea394d0
Document Type: regulatory_guide
Title: An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1635/ML16358A153.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.174
CFR Part: 
CFR Title: 

Content:
e set forth in RGs will be deemed acceptable if they provide a basis for the findings required for the issuance or continuance of a permit or license by the Commission. Paperwork Reduction Act This RG contains voluntary information collections covered by 10 CFR Parts 50 and 52 that are subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et. seq.). These information collections were approved by the Office of Management and Budget (OMB), under control numbers 3150-0011 and 3150–0151. Send comments regarding this information collection to the Information Services Branch, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0011 and 3150–0151) Office of Management and Budget, Washington, DC 20503. Public Protection Notification The NRC may not conduct or sponsor, and a person is not required to respond to, a collection of information unless the document requesting or requiring the collection displays a currently valid OMB control number. DG-1285, Page 3 B. DISCUSSION Reason for Revision This revision (Revision 3) presents up-to-date defense-in-depth guidance using precise language to assure the defense-in-depth philosophy is interpreted and implemented consistently. Revision 3 contains significant changes including expansion of the guidance on the meaning of, and the process for, assessing the defense-in-depth evaluation factors. In addition, this revision adopts the term “PRA Acceptability,” including related phrasing variants, in place of the terms “PRA quality” and “technical adequacy” to describe the appropriateness of the PRA used to support risk-informed licensing submittals. Other changes in this revision include expanding the discussions on uncertainties, including aggregation of risk results, consistent with NUREG-1855, “Guidance on the Treatment of Uncertainties Associated with PRAs in