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
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rate compliance with any technically relevant portions of the Three Mile Island requirements set forth in 10 CFR 50.34(f), except paragraphs (f)(1)(xii), (f)(2)(ix), and (f)(3)(v). 10 CFR 52.47(a)(23) states that a DC application for light-water reactor (LWR) designs must contain an FSAR that includes a description and analysis of design features for the prevention and mitigation of severe accidents, e.g., challenges to containment integrity caused by core-concrete interaction, steam explosion, high-pressure core melt ejection, 19.0-6 Draft Revision 3 – September 2012 hydrogen combustion, and containment bypass. With respect to this regulation, the following items are noted: A. The Statement of Consideration (72 FR 49380) for the revised Part 52 states that postulated severe accidents are not design-basis accidents (DBA) and the severe accident design features do not have to meet the requirements for DBA (see SECY-93-087, “Policy, Technical, and Licensing Issues Pertaining to Evolutionary and Advanced Light-Water Reactor Designs,” dated April 2, 1993). However, the severe accident design features are part of a plant’s design-basis information. B. The Statement of Consideration (72 FR 49394) for the revised Part 52 states that the Commission codified separate criteria in paragraph B.5.c of Section VIII of each DCR for determining if a departure from design information that resolves these severe accident issues would require a license amendment. The final rule amends paragraph B.5.c to clarify that the special process applies to ex-vessel severe accident design features that are described in the plant-specific DCD. C. For purposes of applying the special criteria in paragraph B.5.c of Section VIII, severe accident resolutions are limited to those design features where the intended function of the design feature is relied upon to resolve postulated accidents when the reactor core has melted and exited the reactor vessel (ex- vessel severe accidents) and the