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:
ed under the internal events, internal flood, internal fire, seismic, high wind or external flood hazards groups and cannot be screened out by a screening analysis, as described in regulatory position C.1.2.6. The objective for each technical element is briefly described and the characteristics and attributes needed to achieve the objective are provided in Table 10. The technical elements for an Other Hazards, at-power PRA are: • Other Hazard analysis • Other Hazard fragility analysis • Other Hazard plant response analysis Screening methods can often be employed to show that the contribution of a hazard to CDF and/or LERF/LRF is insignificant. The considerations in this section apply to those hazards identified in Table D-1 of Appendix D that are not screened out based on a screening and conservative analysis. It should be noted that because of the limited collective experience of the analysis community in the area of Other Hazards PRA, 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, at-power PRA which 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.1.2.1 and C.1.2.2, as necessary. Other Hazard Analysis establishes the frequency of occurrence of different intensities of the hazard being analyzed and uses a site-specific probabilistic evaluation that is based on recent available data and site-specific information. Historical data or a phenomenological model, or a mixture of the two is used in the analysis. Other Hazard Fragility Analysis is an evaluation that is performed to estimate the fragility or vulnerability of a structure, or system, or component (or their combination) whose failure contributes to core damage or large early release (or large release). The fragility analysis uses plant-specific