Document: NRC Regulatory Guide
Document ID: cde52d5a-adf9-49be-9d1f-59449dfca895
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:
h an investigation. However, a physical walkdown of a plant in the pre-operational phase of development may not always be possible. Performing an investigation instead of a walkdown when a walkdown is possible may result in a mischaracterization the plant response in the PRA. partitioning elements that define each flood area; (c) any walkdowns or, for PRAs performed during the preoperational phase, investigation(s) performed in support of the plant partitioning; … FLPP-C2 through FLPP-C3 ------------------------ No objection ---------------------------------- Section 4.3.8.2 Section text ------------------------ No objection ---------------------------------- Table 4.3.8.2-1 HLR-FLSO-A and HLR-FLSO-B ------------------------ No objection ---------------------------------- Table 4.3.8.2-2 FLSO-A1 ------------------------ No objection ---------------------------------- FLSO-A2 Fluid sources other than water and steam can produce flooding effects that are unlike water and steam and may result in risk- significant contributors. A lack of consideration of other fluid sources besides water may exclude significant sources of flooding and underestimate risk. Clarification IDENTIFY the potential flood sources that include water, steam, and other liquids (e.g., lubricating oil, fuel oil). RG 1.247, Appendix A, Page A-24 Table A-9. Staff Position on ASME/ANS RA-S-1.4-2021, Technical Requirements for Internal Flood Analysis Index No. Issue Position Resolution FLSO-A3 through FLSO-A6 ------------------------ No objection ---------------------------------- FLSO-A7 A walkdown should be performed for post-operational plants and should not be replaced with an investigation. However, a physical walkdown of a plant in the pre-operational phase of development may not always be possible. Performing an investigation instead of a walkdown when a walkdown is possible may result in a mischaracterization the plant response in the PRA. Clarification … CONFIRM the accuracy of information