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:
ed and blacked-out unit’s onsite EAC power supplies, for valve position indication and closure for containment isolation valves that may be in the open position at the onset of an SBO. This does not include the following valves: i. Valves normally locked closed during operation ii. Valves that fail closed on a loss of power iii. Check valves 8.4-11 March 2007 iv. Valves in nonradioactive closed-loop systems not expected to be breached in an SBO (not including lines that communicate directly with containment atmosphere) v. Valves of less than 3-inch nominal diameter 3. AAC Power Sources. One acceptable means of complying with the requirements in 10 CFR 50.63 involves the provision of an AAC source of sufficient capacity, capability, and reliability (for operation of all systems necessary for coping with SBO and for the time necessary to bring the plant to, and maintain it in, safe-shutdown condition (non-DBA)) that will be available on a sufficiently timely basis. For new ALWR plants, the Commission has established a policy (Ref. 23) that such plants should have an AAC power source of diverse design and capable of powering at least one complete set of normal shutdown loads. In SECY-94-084 and SECY-95-132 (Ref. 26), the Commission modified this criteria for ALWRs that use passive safety systems. Specifically, an AAC power source is not necessary for passive plant designs (such as the AP1000) that (a) do not need ac power to perform safety-related functions for 72 hours following the onset of an SBO and (b) meet the guidelines in Section C.IV.10 of RG 1.206 regarding RTNSS. EDGs in excess of minimum redundancy criteria for NPP onsite power systems, nearby or onsite gas turbine generators, portable or other available compatible diesel generators, or hydrogenerators may serve as AAC power sources. The design should meet the recommendations in Sections C.3.2.5, C.3.3, and C.3.5 and Appendices A and B to RG 1.155. It is acceptable for AAC power sources to be normally