Document: NRC Regulatory Guide
Document ID: 22ccfd5e-c5d8-4615-a02c-32369aa9f533
Document Type: regulatory_guide
Title: Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1930/ML19308B636.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.200
CFR Part: 
CFR Title: 

Content:
------------------- SFR-D6 In 2009 (SFR-E3) indicates that if component screened out during or following the walkdowns, document anchorage calculation and provide the basis. However, this statement is removed in the code case and it is not clear if screening out equipment during walkdowns is allowed. Qualification Add the following or equivalent as a new SFR-D6: IDENTIFY credible seismic-induced failure for the fire sources provided in SPR-C4. If components are screened out during or following the walkdown, PROVIDE the basis justifying such a screening. SFR-D7 This supporting requirement appears to prejudge which seismic interactions have the potential to be “risk- significant” prior to the walkdown. If the intent is that such information will be provided to the walkdown team by the plant-systems analyst it appears to be premature to expect such Clarification IDENTIFY potential risk-significant credible seismic interactions including proximity impacts, falling hazards, and differential displacements (e.g., failure and falling of masonry walls and nonseismically designed SSCs, impact between cabinets, differential building displacements), and EVALUATE the consequences of such interactions on SSCs contained in the systems model and on the credited operator actions. (See HLR-SPR- D.) DG-1362, Appendix B, Page B-16 Table B-1. Staff Position on ASME/ANS RA-S Case 1, “Case for ASME/ANS RA-Sb-2013 Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment of Nuclear Power Plant Applications,” Technical and Peer Review Requirements of a Level 1, Seismic PRA for the At-Power Operating Mode Index No Issue Position Resolution information to be available at the time of walkdown. Further, such an intent or appearance of intent can lead to an argument for excluding the plant-systems analyst from the walkdown. The second part of the SR starting with “EVALUATE the consequences…” is expected to capture the “risk-importance” of the identified