Document: NUREG-0800
Document ID: 4e1d86bd-74a5-4678-8bc0-ffce3ba28ea0
Document Type: srp
Title: RISK-INFORMED INSERVICE TESTING
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0428/ML042880272.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.7
CFR Part: 
CFR Title: 

Content:
an 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 3.9.7-1 1 Rev. 0-August 1998 addition, components that have experienced repeated failures should be reviewed to see whether the testing scheme (interval and methods) would be considered adequate to support the performance credited to them in the risk analysis. * The evaluation should be performed so that the truncation of LSSCs is considered. It is preferred that solutions be obtained form a re-solution of the model, rather than a requantification of CDF and LERF cutsets. * The cumulative impact of all RI-IST program changes (initial approval plus later changes) should comply with the guidance in Regulatory Position 2.3.3 of Regulatory Guide 1.175 and Section 2.2.4 of Regulatory Guide 1.174. 8. Integrated Decisionmaking The licensee's RI-IST program submittal should meet the acceptance guidelines contained in Sections II.A.1 through 7 (above) or should justify why an alternate approach is acceptable. Proposed changes to IST strategies should be evaluated in an integrated fashion which takes into account traditional and probabilistic engineering information, supplemented by a step-wise implementation plan and a performance monitoring and corrective action plan. General acceptance guidelines for this integrated decision process are provided in Regulatory Guide 1.174, and they consist of the following key principles: 1) The proposed change meets the current regulations unless it is explicitly related to the requested exemption or rule change. 2) The proposed change is consistent with the defense in depth philosophy. 3) The proposed change maintains sufficient safety margins. 4) When proposed changes result in an increase in core damage frequency and/or risk, the increases should be small and consistent with the intent of the Commission's