Document: NUREG-0800
Document ID: 7205f369-90a8-45ce-8b98-8c5831c9ff41
Document Type: srp
Title: Revision 3 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070710497.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8
CFR Part: 
CFR Title: 

Content:
eatures, automatic and manual controls, test features, protective trip and lockout features, local/remote control transfer features, and the diesel-generator breaker. BTP 8-7-2 Revision 3 - March 2007 Operating experience (see Ref. 5) has shown that there have been incidents in which diesel- 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 (1) sharing of annunciator stations for both disabling and nondisabling alarm conditions, (2) wording on annunciator windows for disabling conditions that did not specifically say a diesel-generator unit was unavailable for an emergency demand, and (3) 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 adequately responding to an emergency demand include nonreset of trips/lockouts, improper mode or control switch positioning, loss of control voltage, and low starting air pressure. For the operator to act appropriately to supply emergency power when required in the operation of diesel-generator units, it is essential that accurate and sufficient information about the status of the units (e.g., a unit is under test, a unit is locked out for repair, maintenance, or otherwise unavailable) be available upon which to base decisions. B. BRANCH TECHNICAL POSITION 1. Diesel-generator unit bypass or deliberately induced inoperability status should be automatically indicated in the control room when the bypass or deliberately induced inoperable condition can be expected to occur more frequently than once per year and can render the unit unavailable to adequately respond to an automatic or operator-initiated emergency demand. Manually induced indication may be