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:
y as described in the final safety analysis report (FSAR), the subject of 10 CFR 50.59, “Changes, tests and experiments” (Ref. 13)). This RG also makes use of the Commission’s Safety Goal Policy Statement (Ref. 14). As discussed in Section C, one key principle in risk-informed regulation is that proposed increases in risk are small and are consistent with the intent of the Commission’s Safety Goal Policy Statement. The safety goals and associated quantitative health objectives (QHOs) define an acceptable level of risk that is a small fraction (0.1 percent) of other risks to which the public is exposed. The risk acceptance guidelines provided in Section C.2.4 of this RG are defined for LWRs in terms of CDF, LERF, and the change in CDF and LERF (i.e., ΔCDF and ΔLERF) risk metrics. These risk metrics are based on subsidiary objectives derived from the safety goals and their QHOs. In particular, the CDF risk metric is used as a surrogate for the individual latent cancer fatality risk and the LERF risk metric is used as a surrogate for the individual early fatality risk. As discussed in Section A of this RG, RG 1.200 is an important related guidance document that describes one acceptable approach for determining whether the base PRA, in total or the parts that are used to support an application, is acceptable such that the base PRA can be used in regulatory 1 The NRC’s Risk-Informed Activities webpage can be accessed at https://www.nrc.gov/about-nrc/regulatory/risk- informed/rpp.html. DG-1285, Page 5 decisionmaking for LWRs. Figure 1, which is taken from RG 1.200, is intended to illustrate the relationship of this RG to some risk-informed activities, other application-specific guidance, RG 1.200, consensus PRA standards, and industry programs. Figure 1. Relationship of Regulatory Guide 1.174 to other risk-informed guidance This regulatory guide describes an acceptable approach for assessing the nature and impact of proposed licensing basis (LB) changes by