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:
ional engineering evaluations, sensitivity studies, operational experience, engineering judgment, and current regulatory requirements. • The technical information basis was adequate for the scope of the application. In particular, the analysis of success and failure scenarios was adequate to identify the roles played by the SSCs affected by the application, the quantification of the frequency of these scenarios was adequate to establish the safety significance of the SSCs, and the causal models were adequate to establish the effects of the proposed changes in the program. • The safety significance of components affected by the proposed application but not modeled in the PRA was evaluated in a systematic manner. This included a search of components that might contribute to initiating event occurrence, mitigating system components that were not modeled in the PRA because their failure was not expected to dominate system failure in the baseline configuration, and components in systems that do not play a direct role in accident mitigation but do interface with accident mitigating systems. • The process applied by the licensee to overcome limitations of PRA was appropriate. Where decisions were made that do not follow straightforwardly from the PRA, a technical basis was provided that shows how the PRA information and the supplementary information validly combine to support the finding. No findings contradict the PRA in a fundamental way. SRP 19-C1 APPENDIX C CATEGORIZATION OF PLANT ELEMENTS WITH RESPECT TO SAFETY SIGNIFICANCE For several proposed applications in risk-informed regulation, one of the principal activities is the categorization of SSCs and human actions with respect to their safety-significance. This appendix discusses how to review approaches that may be used in this categorization process. The first review consideration is the definition of safety-significance as it applies to SSCs and human actions for a specific application. A related, but not