Document: NUREG-0800
Document ID: ac43f632-9db1-4857-9f56-bfba45965456
Document Type: srp
Title: * These are modifications to a plant’s design, operations, or other activities that require NRC approval. These modifica
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0232/ML023250195.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19
CFR Part: 
CFR Title: 

Content:
opriate 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. SRP 19-A14 • The licensee has systematically considered the possibility that individual components could be performing more poorly than the average associated with their class, and has avoided relaxation for those components to the point where the unavailability of the poor performers would be appreciably worse than that assumed in the risk analysis. • The changes to the parameter values impacted by the application are both justified and reasonable. • Data used to support changes to the plant's design or operations are supported by an appropriate performance monitoring program. A.7 Modeling of Common Cause