Document: NUREG-0800
Document ID: b8d2b8f5-432a-4c0a-81ab-20231f7d0f28
Document Type: srp
Title: PROBABILISTIC RISK ASSESSMENT AND SEVERE ACCIDENT EVALUATION FOR
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1508/ML15089A068.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.0
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Content:
ion 3 – December 2015 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 NRC staff reviews the findings of the peer review to Part 4 of the ASME/ANS PRA Standard, if available. The reviewer reviews the applicant’s assessment of the risk associated with internal fires. NUREG/CR-6850 (EPRI 1011989), “Fire PRA Methodology for Nuclear Power Facilities,” issued September 2005 and EPRI TR-100370, “Fire-Induced Vulnerability Evaluation (FIVE),” EPRI, April 1992 are methods acceptable to the staff for performing fire PRA in support of certification of a new reactor design or initial licensing of a new reactor. The FIVE methodology is considered to be a simplified method suitable for identifying fire vulnerabilities and performing screening evaluations. NUREG/CR-6850 is considered to be a preferable method for performing fire PRA to support applications for design certification or a COL because methodological issues raised in past fire risk analyses, including individual plant examination of fire analyses, have been addressed in NUREG/CR-6850. Reviewers may 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 may be acceptable if conservative assumptions are used such that it is reasonable to conclude that the results bound those expected with the more detailed approach described in