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:
eful means to identify improvements to current IST practices during the risk-informed application process by identifying components that are high risk contributors which may benefit from more frequent tests or enhanced testing methods. 7. Evaluating the Effect of Proposed Changes on Overall Plant Risk One element in the approval of RI-IST changes is that proposed increases in core damage frequency (CDF) and large early release frequency (LERF) are small and consistent with the intent of the Commission's Safety Goal Policy Statement. In calculating this change in risk, the licensee should have accounted for changes in component reliability/availability as a function of test intervals and test methods. In addition, the affects of program changes on initiating event 3.9.7-4 Rev. 0-August 1998 frequency and common cause failures should have been considered. The use of appropriate data (including generic and plant-specific component failure rates, and human error probabilities and recovery probabilities) should have been justified as part of the calculation of the risk change. 8. Integrated Decisionmaking Justification of changes to the IST program should be based on results from both traditional and probabilistic engineering analyses. These analyses should reflect the current plant design and operating experience. Uncertainties in analysis models should be addressed by a step- wise implementation plan, and a performance monitoring and corrective action plan. The proposed change will be acceptable when all these elements are combined in a complementary fashion to show that an acceptable level of quality and safety is provided. B. IMPLEMENTATION, PERFORMANCE MONITORING, AND CORRECTIVE ACTION 1. Program Implementation The licensee should have an implementation plan and schedule established for testing all high and low safety significant components identified in its RI-IST program. The staff should verify that the plan contains test strategies (i.e., frequencies and