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:
ted collective experience of the analysis community in the area of PRA for other hazards, an extensive peer review is particularly important for such a PRA. PRA models of other hazards are based on an existing up-to-date internal events PRA that is modified to include the impact of the hazard under consideration. Because of its dependence on the internal events model, the other hazard analysis incorporates the elements of Regulatory Positions C.1.3.1 through C.1.3.7 of this RG, as necessary. The objective of the other hazards analysis PRA is to establish the frequency of occurrence of different intensities of the hazard being analyzed. The analysis uses a site-specific probabilistic evaluation that is based on current generic or site-specific information. Historical data or a phenomenological model, or a mixture of the two is used in the analysis. The characteristics and attributes needed to achieve the objectives of the other hazards analysis element are as follows: • The analysis results in the hazard’s frequency of occurrence at the site. • The analysis is based on site-specific data or justified generic data, as applicable. • The analysis reflects current information. • The analysis uses historical data, or a phenomenological model, or a mixture of the two. • The analysis identifies and characterizes the uncertainties related to other hazards. The objective of the other hazards fragility analysis is to perform an evaluation to estimate the fragility or vulnerability of an SSC (or combination of SSCs) whose failure contributes to plant risk. The fragility analysis uses plant-specific information and an accepted engineering method for evaluating failures. The characteristics and attributes needed to achieve the objectives of the other hazards fragility analysis are as follows: • The analysis is plant-specific. • The analysis uses SSC-specific information. • The analysis uses accepted engineering methods. RG 1.247, Page 43 • Walkdowns or the