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:
I-IST program should appropriately consider both plant-specific and generic data. The licensee should determine whether individual components affected by the change are performing more poorly than the average associated with their class; the licensee should avoid relaxing IST for those components to the point that the unavailability of the poor performers would be appreciably worse than that assumed in the risk analysis. In addition, the licensee should review those components that have experienced repeated failures to see whether the testing scheme (interval and methods) would be considered adequate to support the performance credited to them in the risk analysis. e. The evaluation should consider the truncation of LSSCs. It is preferred that solutions be obtained from a re-solution of the model rather than a requantification of CDF and LERF cut sets. f. The cumulative impact of all RI-IST program changes (initial approval plus later changes) should comply with the guidance given in this section. 2.3 Integrated Decisionmaking In accordance with Section C.2.6 of RG 1.174, the results of the evaluations under Sections C.1, C.2, and C.3 should be considered in an integrated manner to determine whether the licensee considers it acceptable to submit an alternative request to implement a proposed RI-IST program in accordance with 10 CFR 50.55a(z)(1). PRA results are compared to numerical acceptance guidelines, along with other deterministic considerations, operating experience, lessons learned from previous changes, and the implementation and monitoring program. The licensee’s determination of the acceptability of submitting the proposed change to implement an RI-IST program in accordance with 10 CFR 50.55a(z)(1) should be based on all these considerations and not solely on the numerical results of the PRA. Numerical PRA results should be just one input into the decisionmaking and help in building an overall picture of the risk RG 1.175, Page 19 implications of the