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:
s of Operation) 1. Given that shutdown risk may be highly outage-specific, the staff reviews the shutdown PRA insights to confirm that operational assumptions used to develop an average shutdown model (e.g., use of nozzle dams, outage schedule, containment status, procedural requirements) have been clearly documented in the FSAR. If licensee practices deviate dramatically from these assumptions in the future, the insights obtained from the shutdown PRA may no longer be valid. It is the COL applicant’s responsibility to confirm the assumptions made at the DC stage, and if done properly should capture any significant differences. 2. The staff reviews the applicant’s assumptions related to equipment availability and compares them to TS requirements. Risk-significant equipment should be evaluated with respect to 10 CFR 50.36(c)(2)(ii)(D) to determine whether additional TS requirements are needed. The staff may also review the results of sensitivity studies 4 Support from an independent contractor or staff in the Office of Research may be necessary. 19.0-24 Draft Revision 3 – September 2012 performed to demonstrate the risk benefit of equipment that is controlled only by voluntary administrative controls (e.g., maintenance rule implementation). 3. The staff reviews the applicant’s implementation of the applicable expeditious actions outlined in NRC Generic Letter (GL) 88-17 (Reference 23). The staff needs to ensure that the applicant is meeting the expeditious actions consistent with the guidance for meeting the guidelines in GL 88-17 which are described in detail in enclosures 1 and 2 of the GL. Deviation from GL 88-17 guidance could lead to configurations where cold leg penetrations are permitted to be open in Pressurized Water Reactors (PWRs) without the appropriate steam generator (SG) manway open or when nozzle dams are installed in the wrong order. Such configurations may invalidate PRA results. Staff may review NRC Information Notice No. 88-36 (Reference