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:
Guide 1.206, Section C.I.8.3.1. Regulatory Guide 1.206, Section C.III.1, Chapter 8, provides similar guidance for COL applications that are based on certified ALWR designs. Regarding the review of the electrical protective trip circuits of the diesel generator sets, Positions C.1.7 and C.1.8 of Regulatory Guide 1.9 are used as an evaluation guide. The capability of the automatic sequential loading circuits to reset during a sustained 8.3.1-29 Revision 3 - March 2007 low-voltage condition on the diesel generators is reviewed to ensure that upon restoration of normal voltage, the safety-related loads can be connected in the prescribed sequence. Otherwise, the reconnection of all the loads at the same time could result in an overload condition causing the trip of the respective diesel generator. In ensuring that those safety-related loads being powered through latched-type breakers are capable of being reconnected to their respective buses after restoration of power, the design should provide for resetting the breaker anticycle feature when there is an undervoltage condition. The normal function of this feature is to prevent immediate reclosure of a breaker following a trip. Where the proposed design provides for the sharing of diesel generators between units at the same site, and connection and disconnection of non-Class 1E loads to and from the Class 1E distribution buses, particular attention is given in the review to ensure that the implementation of such design provisions does not compromise the capacity or capability of the standby power supplies. Pursuant to GDC 5, diesel generators may not be shared unless it can be shown that the diesel generators are capable of performing all necessary safety functions in the event of an accident in one unit and an orderly shutdown 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,