Document: NUREG-0800
Document ID: 33d57664-26a3-4d30-807d-2ce020de062a
Document Type: srp
Title: STATION BLACKOUT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740424.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.4
CFR Part: 
CFR Title: 

Content:
- May 2010 $ 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 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 the plant. The following summarizes this process: A. Characteristics of the offsite power system that have been found to contribute to the expected frequency of a LOOP are examined and an appropriate AOffsite Power Configuration Group@ (designated P1, P2, and P3) is selected from Table 4 of RG 1.155. The assumptions used in meeting 10 CFR 50.63 should remain valid for the life of the NPP. B. The redundancy of the onsite EAC power sources (i.e., the number available for decay heat removal minus the number needed for decay heat removal) is determined and an appropriate AEmergency AC Power Configuration Group@ (designated A, B, C, or D) is selected from Table 3 of RG 1.155. The number of EAC power supplies needed for SBO should be based on the ac loads necessary at each unit to achieve and maintain safe shutdown with offsite power unavailable. For single unit or multiunit sites having normally dedicated power supplies, the number of EAC power sources needed is determined by counting the number of EAC power supplies on a per-unit basis that are necessary to operate safe-shutdown equipment following a LOOP. For multiunit sites having shared power supplies, the number of EAC power sources needed is determined by counting the total number of standby power supplies necessary to operate safe-shutdown equipment following a LOOP. The determination of EAC power configuration groups does not count special-purpose