Document: NRC Regulatory Guide
Document ID: 08964ae0-0fa8-4e51-af44-0c6a1ee6e94c
Document Type: regulatory_guide
Title: Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power Plants
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1221/ML12216A011.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.108
CFR Part: 
CFR Title: 

Content:
mponents). Instrumentation sensors should be readily accessible and designed so that their inspec- tion and calibration can be verified in place. Testability should be considered in selecting critical components, and the overall design should include status indication and alarm features. (3) Periodic testing of diesel generator units should not impair the capability of the unit to supply emergency power within the required time. Where necessary, diesel generator unit design should include an emergency override of the test mode to permit response to bona fide signals. (4) A surveillance system should be provided with remote indication in the control room as to diesel generator unit status, i.e., under test, ready- standby, lockout. A means of communication should also be provided between diesel generator unit testing locations and the main control room to ensure that the operators are cognizant of the status of the unit under test. (5) The surveillance system should indicate which of the diesel generator protective trips is ac- tivated first in order to facilitate trouble diagnosis. (6) All diesel generator protective trips should be in force during diesel generator unit testing. c. Detailed step-by-step procedures should be provided for each test under Regulatory Position C.2. The procedures should identify those special arrange- ments or changes in normal system configuration that must be made to put the diesel generator unit un- der test. Jumpers and other nonstandard configura- tions or arrangements should not be used subsequent to initial equipment startup testing. d. Subsequent to any failure, the cause should be determined and corrective action taken in a timely manner, with emphasis on preventing reoccurrence of the failure. 2. Testing a. Testing of diesel generator units during the plant preoperational test program and at least once every 18 months should: (1) Demonstrate proper startup operation by simulating loss of all a.c. voltage and demonstrate that