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:
ther, the same threshold may not be applicable to a range of sites and, for such cases, use of a single threshold would need justification. Inappropriate fragility thresholds may result in inadvertent screening out of components from inclusion in an SPRA and/or an underestimation of risk. Clarification SPECIFY the basis and methodologies established for achieving the fragility thresholds defined in Requirement SPR-B5 justifying the applicability to the plant and site or range of sites identified in SHA-A1. RG 1.247, Appendix A, Page A-41 Table A-11. Staff Position on ASME/ANS RA-S-1.4-2021, Technical Requirements for Seismic PRA Index No. Issue Position Resolution Table 4.3.10.2-5 SFR-D1 ------------------------ No objection ---------------------------------- SFR-D2 A walkdown should be performed for post-operational plants as part of an investigation. However, a physical walkdown of a plant in the pre-operational phase of development may not always be possible. Performing an investigation that involves something less than a walkdown for post-operational plant may result in a mischaracterization the plant's as-built design in the PRA. Clarification EVALUATE the seismic capacity of the as-designed, or as-built, or as-operated or as- intended-to-operate plant conditions via walkdowns or, for PRAs performed during the preoperational phase, investigation(s). SFR-D3 and SFR-D4 ------------------------ No objection ---------------------------------- SFR-D5 Pathways for operators to access SSCs or controls outside the control room and potential pathway unavailability should be included in the walkdown evaluation of potential functional and structural failure mechanisms, equipment anchorage, and support load paths to ensure that these unavailabilities are accounted for in the feasibility evaluation of operator actions considered for the SPRA. The Clarification EVALUATE potential functional and structural failure mechanisms, equipment anchorage, and support load path., and