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:
element) is added to yield the total risk values DG-1362, Page 24 Table 5. Summary of Technical Characteristics and Attributes of an Internal Fire PRA for the At-Power Operating Mode Element Technical Characteristics and Attributes Seismic/Fire Interactions • Potential interactions resulting from an earthquake and a resulting fire that might contribute to plant risk are reviewed qualitatively • Qualitative assessment verifies that such interactions have been considered and that steps are taken to ensure that the potential risk contributions are mitigated Technical Elements for Seismic, At-Power PRA This section identifies the technical elements for a seismic, at-power PRA. The objective for each technical element is briefly described and the characteristics and attributes needed to achieve the objective are provided in Table 6. It is assumed that the seismic PRA is based on modifications made to an existing up-to-date internal events, at-power PRA. The technical elements for a seismic, at-power PRA are: • Seismic hazard analysis • Seismic fragility analysis • Seismic Plant response analysis Earthquakes can cause different initiating events than those considered in an internal-event PRA, and can cause simultaneous failures of multiple redundant components, an important common-cause effect that is included in a probabilistic seismic analysis. All possible levels of earthquakes along with their frequencies of occurrence and consequential damage to plant systems and components are considered in a probabilistic seismic analysis. Because of its dependence on the internal events model, the seismic PRA incorporates the elements of regulatory positions C.1.2.1 and C.1.2.2, as necessary. Seismic Hazard Analysis is used to express the seismic hazard in terms of the frequency of exceedance for selected ground motion parameters during a specified time interval using a site-specific probabilistic hazard analysis that incorporates the available recent site-specific