Document: NRC Regulatory Guide
Document ID: 47b09be1-4bf8-45f9-a099-7fed871c09bd
Document Type: regulatory_guide
Title: Plant-Specific, Risk-Informed Decisionmaking: Inservice Testing (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2114/ML21140A055.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.175
CFR Part: 
CFR Title: 

Content:
and is included as one of the key principles in Regulatory Position C.2 of RG 1.174. Regulatory Position C.2.1.2 of RG 1.174 states “[w]ith sufficient safety margins, (1) the codes and standards or their alternatives approved for use by the NRC are met and (2) safety analysis acceptance criteria in the licensing basis (e.g., FSAR, supporting analyses) are met or proposed revisions provide sufficient margin to account for uncertainty in the analysis and data.” The categorization process might identify components currently not included in the IST program, and their addition as HSSCs will clearly improve safety margins. It is also important that the performance-monitoring program be capable of quickly identifying significant degradation in performance so that, if necessary, corrective measures can be implemented before the margin to failure is significantly reduced. The improved understanding of the relative importance of plant components to risk resulting from the development of the RI-IST program should promote an improved understanding of how the components in the IST program contribute to a plant’s margin of safety, and this should be discussed in the application. 2.2.3 Evaluation of Risk Impact This section discusses issues specific to the RI-IST process. RG 1.174 contains much of the general guidance that is applicable to this topic. The licensee may use its PRA to address the principle that proposed increases in CDF and LERF are small and are consistent with the intent of the Commission’s Safety Goal Policy Statement. A PRA used in a risk-informed application should be performed correctly, in a manner consistent with accepted practices. RG 1.200 describes one acceptable approach for determining whether the acceptability of the PRA, in total or the parts that support an RG 1.175, Page 13 application, is sufficient to provide confidence in the results, such that the PRA can be used in regulatory decisionmaking for LWRs. In an RI-IST program, information