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:
k valves, and in Supplement 6 to NRC Generic Letter 89-10 and Section 3.5 of ASME Code Case OMN-1 (Ref. 25) for MOVs, as well as in other NRC-endorsed documents. 3.3 Performance Monitoring Performance monitoring in RI-IST programs refers to the monitoring of IST data for components within the scope of the RI-IST program (i.e., including both HSSCs and LSSCs). The purpose of performance monitoring in an RI-IST program is twofold. First, performance monitoring should help confirm that no insidious failure mechanisms that are related to the revised test strategies become important enough to alter the failure rates assumed in the justification of program changes. Second, performance monitoring should, to the extent practicable, ensure that adequate component capability RG 1.175, Page 24 (i.e., margin) exists, above that required during design basis conditions, so that component operating characteristics over time do not result in reaching a point of insufficient margin before the next scheduled test activity. RG 1.174 provides guidance on performance monitoring when testing under design basis conditions is impracticable. In most cases, component-level monitoring will be expected. Two important aspects of performance monitoring are whether the test frequency is sufficient to provide meaningful data and whether the testing methods, procedures, and analysis are adequately developed to ensure that performance degradation is detected. Component failure rates cannot be allowed to rise to unacceptable levels (e.g., significantly higher than the failure rates used in the risk evaluation to support the RI-IST program) before detection and corrective action take place. The NRC staff expects that licensees will integrate, or at least coordinate, their monitoring for the RI-IST program with existing programs for monitoring equipment performance and other operating experience at their sites and, when appropriate, throughout the industry. In particular, monitoring performed as part