Document: NUREG-0800
Document ID: 7916b088-fb90-4163-84fe-027bd315bcc5
Document Type: srp
Title: REVIEW OF RISK INFORMATION USED TO SUPPORT PERMANENT PLANT-
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0717/ML071700658.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.2
CFR Part: 
CFR Title: 

Content:
resenting modes of unavailability of SSCs, reviewers should focus on whether the change in parameter values is appropriate and reasonable. The licensee is expected to document the rationale behind the change in parameter values, and that rationale should be carefully reviewed. If generic values are used for the base case parameter values that are candidates for change, reviewers should verify that the conditions under which the generic data apply do not correspond to those which would be more appropriate for a plant with the change incorporated. This should only be a real concern if the plant being changed is somewhat atypical with respect to the issue being addressed by the change. This would not be a concern if plant-specific data were used. Finally, to validate the data used to justify changes in risk-informed applications, it is important for licensees to monitor the performance of components affected by the application. This monitoring should be performed as the proposed application is phased in. For very reliable SSCs, it may be necessary for the licensee to review available operating experience at other plants for applicability to the licensee’s plant to expand the operating experience database. Reviewers should ascertain that the monitoring program is capable of demonstrating that the performance of the components or systems is in accordance with what has been assumed. c. Evaluation Findings Reviewers should verify that information provided and review activities conducted support the following conclusions: • The failure rates and probabilities used, especially those that directly affect the proposed application, appropriately consider both plant-specific and generic data that are consistent with generally accepted values from PRAs of similar plants, and deviations (if any) have been justified on the basis of plant-specific factors. • The licensee has systematically considered the possibility that individual components could be performing more poorly