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:
IST at a plant, additional considerations need to be addressed (e.g., defense-in-depth, common cause, and the single-failure criterion), which may be more constraining than the risk-based criteria in some cases. Consideration should be given to these issues and component performance experience before determining the IST requirements for the various components. IST experience should contribute to an understanding of the important technical bases underlying the existing testing program before it is changed. The critical safety aspects of these bases should not be violated inadvertently in changing over to an RI-IST program, and important plant experience gained through the deterministic IST should be considered during the change. The plant-specific PRA information should include important perspectives with respect to the limitations of PRA modeling and analysis of systems, some of which may not be explicitly addressed within the PRA analysis. An understanding should also be provided about how the proposed changes in pump and valve testing could affect PRA estimates of plant risk. Plant safety experience should provide insights associated with the deterministic analyses (refer to Chapter 15 of the plant final safety analysis report) and any effect that proposed changes in testing might have on the deterministic perspective of overall plant safety. Plant operational input should supplement the insights of plant safety with additional information on the operational importance of components under normal, abnormal, and emergency conditions. There should also be input on operating history, system interfaces, and industry operating experience to supplement information from the IST. DG-1286, Appendix A, Page A-2 Maintenance considerations should provide perspectives on equipment operating history, work practices, and the implementation of the Maintenance Rule (Title 10 of the Code of Federal Regulations (10 CFR) 50.65, “Requirements for Monitoring the Effectiveness of