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:
ing system were within the scope of the Maintenance Rule. However, none of the three plant- level performance criteria described in NUMARC 93-01 (unplanned scrams, unplanned capability loss factor, or unplanned safety system actuations) would monitor the effectiveness of maintenance on these systems. Therefore, the licensee established additional plant-level performance criteria and system- specific performance criteria. Other licensees should consider similar steps under similar situations. Clarification of Maintenance Preventable Functional Failures Related to Design Deficiencies The third paragraph of Section 9.4.5 “Maintenance Preventable Functional Failures (MPFFs)” of NUMARC 93-01 provides guidance on the licensee’s options following a failure and on whether, as a result of the licensee’s corrective actions, subsequent failures would be considered MPFFs. Among other things, this paragraph addresses failures caused by design deficiencies. Ideally, licensees would modify the design to eliminate the poorly designed equipment. However, if the licensee determines that such an approach is not cost effective (e.g., the cost of modification is prohibitive), the licensee has two options: (1) Replace or repair the failed equipment and adjust the preventive maintenance program and inspection activities as necessary to prevent recurrence of the failure. Subsequent failures of the same type that are caused by inadequate corrective or preventive maintenance are MPFFs, and could be repetitive MPFFs. DG-1336, Page 15 (2) Perform an evaluation that demonstrates that the equipment can be run to failure (as described in Section 9.3.3 of NUMARC 93-01). If the equipment can be run to failure, the licensee may replace or repair the failed equipment, but adjustments to the preventive maintenance program are not necessary and subsequent failures would not be MPFFs. Scope of the Hazards to be Considered During Power Operations NUMARC 93-01 provides guidance to licensees on the