Document: NUREG-0800
Document ID: 805f7e09-51a2-413b-92af-e23bb9073497
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070493.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8
CFR Part: 
CFR Title: 

Content:
Guide 1.9,51 consist of the engine, governor, exhaust system, generator, associated excitation and voltage regulation system, combustion air system, cooling water system up to the supply, fuel supply system, lubricating oil system, starting energy sources, starting system and autostart/load features, autostartmatic controls,and manual controls, test features, protective trip and lockout features, local/remote control transfer features, and the diesel-generator breaker.52 Operating experience (see Reference 5) has shown that there have been incidents where diesel- 53 generator units failed to respond to an automatic start signal because control switches or lockout and shutdown relays (which require manual reset) were left in the shutdown condition without control room operators being aware of their status. The principal reasons for this lack of awareness were the (a) sharing of annunciator stations for both disabling and nondisabling alarm conditions; (b) wording on annunciator windows for disabling conditions that did not speci- fically say a diesel-generator unit was unavailable for an automatic emergency startdemand ; 54 and (c) disabling conditions that were not annunciated in the control room. Examples of bypass or deliberately induced inoperable conditions that can render diesel- generator units incapable of adequate response to an emergency demand include nonreset of trips/lockouts, improper mode or control switch positioning, loss of control voltage, and low starting air pressure.55 In order that the operator can act appropriately to supply emergency power when required in the operation of diesel-generator units, it is essential that he has accurate and sufficient information about the status of the units (e.g., is a unit under test; is a unit locked out for repair, maintenance, or otherwise unavailable) be available on which to base his decisions.56 8A-19 DRAFT Rev. 3 - April 1996 2B. BRANCH TECHNICAL POSITION 2.1. Diesel-generator unit bypass or