Document: NRC Regulatory Guide
Document ID: 1731a882-b0c5-418d-b65e-55646c26be5c
Document Type: regulatory_guide
Title: 03/2007
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0703/ML070380553.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.9
CFR Part: 
CFR Title: 

Content:
er cooling at certain temperatures (or both) are normally in operation, this would constitute normal standby conditions for the given plant. 1.6 Design provisions should include the capability to test each emergency diesel generator independently of the redundant units. Test equipment should not cause a loss of independence between redundant diesel generators or between diesel generator load groups. Testability should be considered in selecting and locating instrumentation sensors and critical components (e.g., governor, starting system components). Instrumentation sensors should be readily accessible and designed so that their inspection and calibration can be verified in place. The overall design should include status indication and alarm features. 1.7 Clause 4.5.3.1 of IEEE Std 387-1995 pertains to status indication of diesel generator unit conditions. The following paragraphs should supplement the guidance in this clause: 1.7.1 A surveillance system should be provided with a remote indication in the control room to display emergency diesel generator status (i.e., under test, ready-standby, lockout). A means of communication should also be provided between diesel generator testing locations and the main control room to ensure that the operators know the status of the diesel generator under test. 1.7.2 To facilitate the diagnosis of failure or malfunction, the surveillance system should indicate which of the emergency diesel generator protective trips has been activated first. 1.8 The following should supplement Clause 4.5.4 of IEEE Std 387-1995, which pertains to bypassing emergency diesel generator protective trips during emergency conditions: The emergency diesel generator should be tripped automatically on engine overspeed and generator-differential overcurrent. A trip should be implemented with two or more measurements for each trip parameter with coincident logic provisions for trip actuation. The design of the coincident logic trip circuitry should include