Document: NUREG-0800
Document ID: a2680f96-0e15-402d-89ab-688ff09806a8
Document Type: srp
Title: with respect to the specified station blackout event/duration.13
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070497.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.2
CFR Part: 
CFR Title: 

Content:
mon cause applicability and that corrective action has been taken to reduce subsequent failures. j. The AAC power system is capable of operating during and after a station blackout without any support system being powered from the preferred power supply or the blacked-out unit's emergency ac power sources. k. The portions of the AAC power system subjected to maintenance activities are/will be tested prior to returning the AAC power system to service. l. Plant-specific technical guidelines and emergency operating procedures will be implemented (or are in place, as applicable) that identify those actions necessary for placing the AAC power source in service. m. The AAC power system will be inspected, maintained, and tested periodically to demonstrate operability and reliability. The reliability of the AAC power system should meet or exceed 95 percent as determined in accordance with NSAC-108 (Reference 5) or equivalent methodology. n. Use of EDGs for AAC Power Sources: Where EDGs are identified as AAC power sources, they should meet the criteria listed below: (1) At single unit sites, any emergency ac power source(s) in excess of the number required to meet the minimum redundancy requirements (i.e., single failure) for safe shutdown may be assumed to be available. These emergency ac power sources may be designated as AAC power sources, provided the criteria identified in Position C.3.3.5 of Regulatory Guide 1.155 are met. (2) A single unit that requires one emergency ac source to place the plant in safe shutdown requires one redundant emergency ac power source. For station blackout, both the emergency ac power source and the redundant emergency ac power source are unavailable. An EDG may be designated as an AAC power source only if that EDG is neither the required emergency ac power source nor the redundant emergency ac power source. Therefore, a single unit requiring one emergency ac source for safe shutdown should have at least three EDGs, with one EDG that may be