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:
ign,” issued January 2012 (Ref. 17). • IAEA Safety Standard SF-1, “Fundamental Safety Principles,” issued November 2006 (Ref. 18). These safety guides provide recommendations for performing or managing a probabilistic safety assessment project for nuclear power plants and using it to support safe design and operation. This RG discusses some of the same principles with respect to changes to a plant’s licensing basis. NUREG/KM-0009, “Historical Review and Observations of Defense-in-Depth” (Ref. 19), provides a summary of the various descriptions, discussions, and definitions of defense-in-depth that have been used in literature as well as historical observations on the concept of defense-in-depth. It also references international technical documents relevant to this RG including those that provide different perspectives on and interpretations of defense-in-depth philosophy, which were considered as part of the development of related guidance in this RG. DG-1285, Page 7 C. STAFF REGULATORY GUIDANCE In its approval of the policy statement on the use of PRA methods in nuclear regulatory activities, the Commission stated its expectation that “the use of PRA technology should be increased in all regulatory matters ... in a manner that complements the NRC’s deterministic approach and supports the NRC’s traditional defense-in-depth philosophy.” The use of risk insights in licensee submittals requesting LB changes will assist the staff in the disposition of such licensee proposals. The staff has defined in this RG an acceptable approach to analyzing and evaluating proposed licensing basis changes. This approach supports the NRC’s desire to base its decisions on the results of traditional engineering evaluations, supported by insights (derived from the use of PRA methods) about the risk significance of the proposed changes. Decisions concerning proposed changes are expected to be reached in an integrated fashion, considering traditional engineering and