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:
describe their approach for maintaining and periodically upgrading the PRA in accordance with RG 1.206, Section C.I.19.7 and RG 1.200. For purposes of reporting the effects of plant modifications and changes to the NRC in accordance with the requirements of 10 CFR 50.71(e), the NRC expects the following when changes affect the PRA: A. PRA numerical changes should be reported when the cumulative risk impact of the changes resulting from the plant modifications, design changes or departures from the DC is more than a 10% change (either positive or negative) in the total core-damage frequency or total LRF from what was previously reported. B. All changes in key assumptions per RG 1.200 and all changes in risk insights as defined in RG 1.206 including differences between the updated risk insights and the certified design risk insights should also be reported to the NRC in accordance with the guidance in Section C.III of RG 1.206. C. All changes or departures from the design that result in a revision of PRA-based qualitative results should also be reported to the NRC. 19.0-16 Draft Revision 3 – September 2012 19. 10 CFR 50.71(h)(2) states that each COL holder must maintain and upgrade the PRA required by 10 CFR 50.71(h)(1). This means that COL holders, in accordance with 10 CFR 50.71(h), must upgrade the PRA used to support the COL to cover those initiating events and modes of operation contained in NRC-endorsed consensus standards that exist one year prior to each required upgrade. The ASME PRA Standard describes “PRA upgrade” as the incorporation into a PRA model of a new methodology or significant changes in the scope or capability. This could include items such as new human error analysis methodology, new data, updated methods, new approaches to quantification or truncation, or new treatment of CCF. 20. RG 1.200 describes the elements of a PRA maintenance and update program that is acceptable to the staff. If the staff can confirm that the applicant’s