Document: NRC Regulatory Guide
Document ID: 96ecfd93-e64a-4f35-93fe-d3b95daac61d
Document Type: regulatory_guide
Title: Monitoring the Effectiveness of Maintenance at Nuclear Power Plants + HISTORY –HISTORY 06/2018 – DG-1336 , Proposed Revision 4 09/2011 – DG-1278 , Proposed Revision 3 08/1996 – DG-1051 , Proposed Revision 2 06/1994 – DG-1031, Proposed Revision 1 11/1992 – DG-1020, Proposed Revision 0 (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1812/ML18129A080.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.160
CFR Part: 
CFR Title: 

Content:
could also take the approach that all (or most) SSCs would be handled under 10 CFR 50.65(a)(1) and none (or very few) would be considered under 10 CFR 50.65(a)(2). Licensees may take either approach. Timeliness NUMARC 93-01 states that activities such as cause determinations and moving SSCs from the 10 CFR 50.65(a)(2) to the (a)(1) category must be performed in a “timely” manner. Some licensees have requested that the NRC staff specify a period that would be considered “timely.” To be consistent with the intent of the Maintenance Rule to provide flexibility to licensees, the NRC staff does not consider providing a specific timeliness criterion appropriate. Licensees should undertake and accomplish activities associated with the Maintenance Rule in a manner commensurate with the safety significance of the SSC and the complexity of the issue being addressed. DG-1336, Page 17 Emergency Diesel Generators Industry- and NRC-sponsored probabilistic risk assessments (PRAs) have shown the safety significance of emergency alternating current (ac) power sources. The station blackout rule (10 CFR 50.63, “Loss of All Alternating Current Power”) requires plant-specific coping analyses to ensure that a plant can withstand a total loss of ac power for a specified duration and to determine appropriate actions to mitigate the effects of a total loss of ac power. During the station blackout reviews, most licensees (1) committed to implementing an emergency diesel generator reliability program in accordance with NRC regulatory guidance but reserved the option to later adopt the outcome of Generic Issue B-56 (Diesel Generator Reliability), Resolution of Generic Safety Issues (Formerly entitled "A Prioritization of Generic Safety Issues"), NUREG-0933 (Ref. 17), resolution, and (2) stated that they had an equivalent program or will implement one. Subsequently, utilities docketed commitments to maintain their selected target reliability values (i.e., maintain the emergency