Document: 10 CFR Part 50
Document ID: eca31a68-f139-47aa-918c-e7269c395ee0
Document Type: cfr
Title: Loss of all alternating current power.
Source: 10 CFR Part 50
Source URL: https://www.ecfr.gov/current/title-10/part-50/section-50.63
Revision Date: 
Chapter: 
Section ID: 50.63
CFR Part: 50
CFR Title: 10

Content:
ere onsite emergency ac sources are shared between units, the alternate ac source(s) must have the capacity and capability as required to ensure that all units can be brought to and maintained in safe shutdown (non-DBA) as defined in § 50.2 . If the alternate ac source(s) meets the above requirements and can be demonstrated by test to be available to power the shutdown buses within 10 minutes of the onset of station blackout, then no coping analysis is required. ( 3 ) Regulatory Assessment: After consideration of the information submitted in accordance with paragraph (c)(1) of this section, the Director, Office of Nuclear Reactor Regulation, will notify the licensee of the Director's conclusions regarding the adequacy of the proposed specified station blackout duration, the proposed equipment modifications and procedures, and the proposed schedule for implementing the procedures and modifications for compliance with paragraph (a) this section. [ 53 FR 23215 , June 21, 1988, as amended at 63 FR 50480 , Sept. 22, 1998; 72 FR 49501 , Aug. 28, 2007; 86 FR 43402 , Aug. 9, 2021]