Document: NRC Regulatory Guide
Document ID: 8a2332d3-66ca-40af-84e1-507db8b26559
Document Type: regulatory_guide
Title: TRIAL - Acceptability of Probabilistic Risk Assessment Results for Non-Light Water Reactor Risk-Informed Activities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2123/ML21235A008.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.247
CFR Part: 
CFR Title: 

Content:
Appendix A, Page A-43 Table A-11. Staff Position on ASME/ANS RA-S-1.4-2021, Technical Requirements for Seismic PRA Index No. Issue Position Resolution operational phase, demonstrating that generic or conservative assumptions are bounding for the range of anticipated sites helps ensure that these fragilities can reasonably reflect the as-designed or as-to- be-built plant. If such assumptions cannot be shown to be bounding for the range of anticipated sites, the results may not appropriately reflect the expected plant response. the plant. CC-II CALCULATE realistic seismic fragilities for the failure mechanisms of interest identified in Requirement SFR- E1 using plant-specific data, or JUSTIFY (e.g., through the calculation of integrated risk metrics defined in Requirement RI-B3) the use of generic fragility data (e.g., fragility test data, generic seismic qualification test data, and earthquake experience data) or conservative assumptions for any SSCs as being applicable to the SSC and appropriate for the plant or by showing no masking or differences in insights. SFR-E4 The applicability of generic data to a given SSC should be justified. This is because of the potential for SSCs in NLWR designs that may not correspond to established SSC categories and/or may not be in common SSC locations in the plant. When estimating fragilities for PRAs developed for the pre- operational phase, demonstrating that generic or conservative assumptions are bounding for the range of anticipated sites helps ensure that these fragilities can Clarification CC-I ESTIMATE contact chatter seismic fragilities for relays and other similar devices that affect SSCs identified in the Systems Analysis and JUSTIFY the use of generic fragility data or conservative assumptions as being applicable and appropriate for the plant. CC-II CALCULATE contact chatter seismic fragilities using plant- specific data or JUSTIFY the applicability and use of generic fragility data for relays and other similar