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:
f design load Load-run failures: A load-run failure should be counted when the emergency diesel generator starts but does not pick up the load and run successfully. Any failure during a valid load-run demand should count (see the exceptions below). (For monthly surveillance tests, the emergency diesel generator can be loaded at the rate recommended by the manufacturer to minimize stress and wear.) Any condition identified during maintenance inspections (with the emergency diesel generator in the standby mode) that definitely would have resulted in a load-run failure if a demand had occurred should count as a valid load-run demand and failure. Rev. 4 of RG 1.9, Page 8 Rev. 4 of RG 1.9, Page 9 Exceptions: Unsuccessful attempts to start or load-run should not count as valid demands or failures when they can definitely be attributed to any of the following: • any operation of a trip that would be bypassed in the emergency operation mode (e.g., high cooling-water temperature trip) • malfunction of equipment that is not required to operate during the emergency operating mode (e.g., synchronizing circuitry) • intentional termination of the test because of alarmed or observed abnormal conditions (e.g., small water or oil leaks) that would not have ultimately resulted in significant damage or failure of the emergency generator • component malfunctions or operating errors that did not prevent the emergency diesel generator from being restarted and brought to load within 5 minutes (i.e., without corrective maintenance or significant problem diagnosis) • a failure to start because a portion of the starting system was disabled for test purposes, if followed by a successful start with the starting system in its normal alignment Each diesel generator valid failure that results in declaration of the emergency diesel generator as being inoperable should count as one demand and one failure. Exploratory tests during corrective or preventive maintenance should not count as