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:
wn and cooldown of the remaining units. In ensuring that the proposed design for sharing diesel generators between units meets the requirements of GDCs 5 and 17 as supplemented by GDCs 34, 35, 38, 41, and 44 and satisfies the positions of Regulatory Guide 1.9, the reviewer is guided by Regulatory Guide 1.81. This guide sets forth two principal positions. Position C.3 applies to those construction permit applications docketed after June 1, 1973, and does not recommend the sharing of onsite power systems between units. Conformance of the design with Position C.3 is verified by reviewing the descriptive information, including electrical drawings, to ensure that the onsite power system of each unit is electrically independent with respect to the onsite power system of other units. Position C.2 of Regulatory Guide 1.81 establishes acceptable bases under which sharing of onsite power systems between units is permitted. Conformance with Position C.2 with regard to the adequacy of diesel generator capacity and capability under the sharing mode of operation is verified by following the procedure discussed above for tabulating and summing all loads. In particular, the load tabulation and calculations establishing the diesel generator capacity are examined to ensure that the selected capacity is sufficient to power the minimum engineered safety feature (ESF) loads in any unit and safely shut down the remaining units in the event of an accident in one unit and a single failure or spurious or false accident signal from another unit and loss of preferred power to all the units. In addition, the physical arrangement of instrumentation and control devices on control room panels and consoles in one unit with respect to the other units is examined to ensure that the design minimizes the coordination needed between unit operators to accomplish sharing of the standby power systems. In the absence of specific criteria in IEEE Std 308 governing the connection and disconnection of