Document: NUREG-0800
Document ID: 98a045ec-37ef-46fc-9eaa-9e695c2d6e53
Document Type: srp
Title: OFFSITE POWER SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350488.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.2
CFR Part: 
CFR Title: 

Content:
ubstation. The station layout and the grid system layout drawings are reviewed to determine that all *the above events were included in the analysis. The applicant should include in the grid stability analysis the con- sideration of failure modes that could result in frequency variations exceeding the maximum rate of change determined in the accident analysis for loss of reactor coolant flow. (g) During the review of the electrical schematics, it should be deter- mined that loss of standby power will not result in loss of preferred power, loss of one preferred power circuit will not result in loss of the other circuit, and loss of the main generator will not result in loss of either preferred power circuit. (h) The preferred power system must be independent of the onsite power system. The basis for acceptance is that no single event, including a single protective relay, interlock, or switchgear failure, in the event of loss of all standby power sources, will prevent the separa- tion of the preferred power system from the onsite power distribution system or prevent the preferred power system from accomplishing its 8.2-6 Rev. 3 - July 1983 intended functions. In addition, the preferred and standby power supplies should not have common failure modes. An acceptable design must be capable of restoring the preferred power supply after the loss of either circuit in a time period such that the plant can be safely shutdown, taking into account the effects of a single failure in the onsite distribution system. This item is also addressed in SRP Section 8.3.1. 2. To assure that the requirements of General Design Criterion 18 are satis- fied, the electrical schematics should be examined to determine that the design includes provisions for testing the transfer of power to the onsite distribution system from the main generator supply to the preferred power system, or to any other supply. It should also be established that the circuitry required to perform these transfer functions