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:
Nuclear Regulatory Commission, Washington, D.C. 20555, Attention: Director, Division of Document Control. The testing of the diesel generator unit should simulate, where practicable, the parameters of opera- tion (automatic start, load sequencing, load shed- ding, operation time, etc.) and environments (temperature, humidity, etc.) that would be expected if actual demand were to be placed on the system. This guide provides design and operational provi- sions for the performance of periodic testing of diesel generator units used for onsite electric power for nuclear power plants. A "diesel generator unit" con- sists of the engine, generator, combustion air system, cooling water system up to the supply, fuel supply system, lubricating oil system, starting energy sources, autostart controls, manual controls, and diesel generator breaker. C. REGULATORY POSITION 1. General a. The design of a diesel generator unit should be such that it can accommodate diesel generator testing as defined in Regulatory Position C.2. b. Diesel generator units should be designed to be testable during operation of the nuclear power plant, as well as while the plant is shut down. The design should include provisions so that the testing of the units will simulate the parameters of operation (outlined in Regulatory Position C.2) that would be expected if actual demand were to be placed on the system. (1) Capability should be provided to test each diesel generator unit independently of redundant un- its. Test equipment should not cause a loss of in- dependence between redundant diesel generator units or between diesel generator load groups. (2) Testability should be considered in the selec- tion and location of instrumentation sensors and critical components (e.g., governor, starting system components). 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