Document: NUREG-0800
Document ID: 8dd882f4-a34f-4415-acd1-ebb441c72786
Document Type: srp
Title: PROBABILISTIC RISK ASSESSMENT AND SEVERE ACCIDENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1213/ML12132A481.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.0
CFR Part: 
CFR Title: 

Content:
(2) the applicant’s determination of plant-level HCLPF in accordance with the acceptance criteria given in Section II of this SRP. The staff reviewing the plant system and accident sequence analysis verifies that the applicant has considered random equipment failures, seismic interactions, as well as operator actions in the plant system and accident sequence analysis as applicable. It is important that the plant systems analysis focus on those sequences leading to core damage or containment failures, including applicable sequences leading to the following containment failures: (1) loss of containment integrity, (2) loss of containment isolation, and (3) loss of function for prevention of containment bypass. The applicant should address the following operating modes in the analysis: (1) at power (full power), (2) low power, and (3) shutdown. Design-Specific PRA (Treatment of Internal Fires ) 1. The reviewer considers the extent to which applicant’s assessment of the risk associated with internal fires conforms to the guidance in NUREG/CR-6850 (EPRI 1011989), “Fire PRA Methodology for Nuclear Power Facilities,” issued September 2005. The NRC considers the NUREG/CR-6850 approach to be a state-of-the-art fire risk analysis approach because methodological issues raised in past fire risk analyses, including individual plant examination of fire analyses, have been addressed in NUREG/CR-6850 to the extent allowed by the current state-of-the-art. NUREG/CR-6850 is therefore an acceptable method for performing fire PRA to support applications for design certification or a COL. Reviewers my find that applicants for design certification use an approach to implementing the analysis tasks in NUREG/CR-6850 that is simpler than that suggested in NUREG/CR-6850. This can occur when the specifics of cable routings, ignition sources, and target locations in each fire zone of the plant are not known at the time the design certification application is submitted. Such an approach