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:
vered by the requirements of 10 CFR Part 50 and 10 CFR Part 21, “Reporting of Defects and Noncompliance” (Ref. 2), which the Office of Management and Budget (OMB) approved under OMB control number 3150-0011 and 3150-0035, respectively. The NRC may neither conduct nor sponsor, and a person is not required to respond to, an information collection request or requirement unless the requesting document displays a currently valid OMB control number. B. DISCUSSION An emergency diesel generator selected for use in an onsite electric power system should have the capability to (1) start and accelerate a number of large motor loads in rapid succession, while maintaining voltage and frequency within acceptable limits, (2) provide power promptly to engineered safety features if a loss of offsite power (LOOP) and a design-basis event occur during the same time period, and (3) supply power continuously to the equipment needed to maintain the plant in a safe condition if an extended (e.g., 30-day period should be considered with refueling every 7 days) LOOP occurs. The Institute of Electrical and Electronics Engineers (IEEE) Standard 387, “IEEE Standard Criteria for Diesel-Generator Units Applied as Standby Power Supplies for Nuclear Power Generating Stations” (IEEE Std 387-1995), issued in 1995 (Ref. 3), delineates principal design criteria and qualification and testing guidelines to ensure that selected diesel generators meet performance requirements. Working Group SC 4.2 of Subcommittee 4 (Auxiliary Power) of the IEEE Nuclear Power Engineering Committee developed IEEE Std 387-1995, and the IEEE Standards Board approved the standard on December 12, 1995. A knowledge of the characteristics of each load is essential to establish the bases for selection of an emergency diesel generator that is able to accept large loads in rapid succession. The majority of these emergency loads are large induction motors. At full voltage, this type of motor draws a starting current of five