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:
ent needed to maintain the plant in a safe condition if an extended loss of offsite power oc- curs. Diesel generator units are the most common source of onsite electric power. High reliability must be designed into the diesel generator units and maintained throughout their ser- vice lifetime by appropriate testing, maintenance, and operating programs. Branch Technical Position EICSB 2, "Diesel-Generator Reliability Qualifica- tion Testing," dated 11/24/75, of the Standard Review Plan (Appendix 7-A of NUREG-75/0871) es- tablishes a reliability goal of 0.99 (at a nominal 50% confidence level) and an acceptable qualification testing program for diesel generator units of a type or size not previously used as standby emergency power sources in nuclear power plants. The preoperational and periodic testing provisions set forth in this guide have been designed to provide a basis for taking those corrective actions needed to maintain high inservice reliability of installed diesel generator units. In addi- tion, the data developed will provide an ongoing demonstration of performance and reliability for all diesel generator, units after installation and in service. Reliability objectives concerning the entire onsite electric power system's probability of failure depend on the interconnections among the system's compo- nents and are not within the scope of this guide. "Failure" is taken here to mean the failure to start, accelerate, and assume the design-rated load within and for the time prescribed during an emergency or a valid test. I NUREG-75/087, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants," U.S. Nuclear Regulatory Commission. Copies may be purchased from the National Technical Information Service, Springfield, Virginia 22161. *- B. DISCUSSION The purposes of onsite electric power systems are (1) to provide power promptly to engineered safety *Lines indicate substantive changes from previous issue. USNRC REGULATORY GUIDES