Document: NUREG-0800
Document ID: bc7e4c14-0eaa-4591-a506-23d7893f8a00
Document Type: srp
Title: as establishing acceptable guidance for meeting the requirements of this criterion.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070498.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
g the criteria governing the design of the thermal overload protection for motors of motor-operated safety-related valves, the reviewer is guided by Regulatory Guide 1.106. Regarding the review of the electrical protective trip circuits of the diesel generator sets, Positions 8C.1.7 and 9C.1.8 of Regulatory Guide 1.9 are used as an 106 evaluation guide. The capability of the automatic sequential loading circuits to reset during a sustained 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 must 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. General Design CriterionGDC 5 prohibits sharing unless it can be shown that the diesel generators are capable of performing all required 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 8.3.1-21 DRAFT Rev. 3 - April 1996 units meets the requirements of General Design Criteria 5 and 17 as supplemented by