Document: NUREG-0800
Document ID: ac4cde5a-7464-48b8-9067-860c672cbb68
Document Type: srp
Title: STATION BLACKOUT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550061.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.4
CFR Part: 
CFR Title: 

Content:
thstand and recover from an SBO (coping capability) and, if necessary, make modifications to improve the coping ability. 3. Establish minimum reliability goals for onsite EAC power supplies (typically EDGs) and establish a program to ensure the reliability goals are maintained. 4. Develop procedures and training to cope with and recover from an SBO. The analyses performed to demonstrate compliance with 10 CFR 50.63 should remain valid for the life of the NPP. If the underlying assumptions change during the life of the NPP, licensees are expected to reevaluate the specified coping duration of their NPPs and the accompanying coping analyses using RG 1.155 or NUMARC-8700, Revision 0. To ensure that the requirements of 10 CFR 50.63 are satisfied, the staff should take the following review steps: 1. SBO Coping Duration. The SBO rule requires each plant to justify its specified coping duration by an analysis of site- and plant-specific factors that contribute to the likelihood and duration of an SBO. Because passive plants will not have EAC power sources, applicants for such plants need not evaluate SBO coping duration as long as they are able to demonstrate that the design selected is capable of performing safety-related functions for 72 hours. The 72 hour approach is consistent with the duration approved by the NRC staff for the AP 1000 design. The rule identifies these factors as follows: • The redundancy of the onsite EAC power sources • The reliability of the onsite EAC power sources • The expected frequency of a LOOP • The probable time needed to restore offsite power 8.4-8 March 2007 The staff will review applicant submittals on SBO (i.e., SBO analysis) to determine that the selected coping duration conforms to the guidance provided in Section C.3.1 of RG 1.155, as supplemented by the criteria contained herein. A series of tables in RG 1.155 define each of the above factors and provide a method for determining an acceptable minimum SBO coping duration for