Document: NUREG-0800
Document ID: 81256f55-72dd-4777-9472-f373c71c4554
Document Type: srp
Title: AC POWER SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550065.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
ach light-water-cooled nuclear power plant be able to withstand for a specified duration and recover from a station blackout. As required by 10 CFR 50.63, electrical systems that are necessary support systems for station blackout provide sufficient capacity and capability to ensure that core cooling and appropriate containment integrity are maintained in the event of a station blackout. One acceptable means of complying with 10 CFR 50.63 requirements involves the provision of an alternate ac (AAC) source (as defined in 10 CFR 50.2) of sufficient capacity, capability, and reliability for operation of all systems necessary for coping with station blackout and for the time necessary to bring and maintain the plant in safe shutdown that will be available on a sufficiently timely basis. Also pursuant to 10 CFR 50.63, through citation of the definition of AAC source in 10 CFR 50.2, there should be minimum potential for common mode failure (i.e., acceptable independence) between any AAC power source used for station blackout and the offsite power system or onsite power sources. Electrical ties between these systems, as well as the physical arrangement of their interface equipment, should not prevent the use of any AAC power source during loss of the offsite power system and/or onsite power sources. It is also important that provisions for an AAC source not adversely affect performance of offsite or onsite power system functions. AAC power sources located at or near the plant should conform to guidance provided in Regulatory Guide 1.155 concerning their capacity, capability, and physical independence from onsite safety-related systems and the preferred power system. See SRP Section 8.4 for details of the review of AAC power sources for SBO. As specified in 10 CFR 50.63, the reliability and redundancy of emergency onsite ac power sources must be used as a factor in determining the duration for which the plant must be capable of coping with a station blackout event. A