Document: NRC Regulatory Guide
Document ID: 9a8db182-3194-4663-aeb3-64f2e4edd6aa
Document Type: regulatory_guide
Title: Availability of Electric Power Sources (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1008/ML100840581.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.93
CFR Part: 
CFR Title: 

Content:
cation of the capability of the restored sources. Similarly, whenever the technical specifications allow power operation to continue during a specific degradation level, such continued power operation should be contingent upon the plant-specific technical specification requirement(s) and the following: a. Immediately verify the availability and capability of the remaining sources. b. Verify that the required maintenance activities do not further degrade the power system or in any way jeopardize plant safety. c. Comply with the required actions stipulated for each LCO specified in the plant-specific technical specifications. The conduct of maintenance or surveillance activities should be evaluated to determine compliance with 10 CFR 50.65. The NPP operator should refer to the interface requirements specified in North American Electric Reliability Corporation Standard NUC-001-2, “Nuclear Plant Interface Coordination,” issued January 22, 2010 (Ref. 9), for coordination between the NPP operators and transmission entities for the purpose of ensuring the safe operation and shutdown of the NPP. The NPP operator should validate the accuracy and conservatism of the post-trip voltages predicted by the online grid analysis tool. If notified by the TSO that a trip of the NPP would result in inadequate offsite power post-trip voltages or in other transmission contingencies that would result in offsite power voltages less than the NPP design requirements, the NPP operator should declare the offsite power inoperable and then follow the actions specified in the plant-specific technical specifications. 1. The available offsite ac power sources are one less than the LCO. If the available offsite ac power sources are one less than the LCO, power operation may continue for a period that should not exceed 72 hours if the electric grid system capability and reserves are such that a subsequent single failure (including a trip of the unit’s generator but excluding an unrelated