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
CFR Part: 
CFR Title: 

Content:
maintenance should commence at the time of application for both DC and COL applicants. If the certification is issued, the generic PRA would not need to be updated except as appropriate in connection with a DC amendment request. The NRC staff should confirm that the PRA maintenance process provides that the PRA performed in support of a COL application be updated to reflect plant modifications if there are changes to the design during the design, construction and operation phases of the facility. 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 CDF 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. 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. 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 proposed program includes the