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:
c technical guidelines and emergency operating procedures should incorporate corresponding procedures. Load shedding should not commence during the first 30 minutes of the SBO event. M. The ability to maintain appropriate containment integrity should be addressed. Appropriate containment integrity for SBO means that adequate containment integrity is ensured by providing the capability, independent of the preferred 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 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 criterion 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.