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:
sis events), which makes reliability monitoring impractical. DG-1336, Page 13 In accordance with the rule, structural monitoring programs must provide reasonable assurance that in scope structures are capable of fulfilling their intended functions. An acceptable structural monitoring program for the purposes of the Maintenance Rule should have the attributes discussed in Section 9.4.1.4 “Structure Level” of NUMARC 93-01. Structures monitored in accordance with 10 CFR 50.65(a)(1) would continue to be monitored until the degradation and its cause have been corrected. For these structures, there would be additional degradation-specific condition monitoring and increased frequency of assessments until the licensee’s corrective actions are completed and the licensee is assured that the structure can fulfill its intended functions and will not degrade to the point that it cannot fulfill its design basis. Consistent with the intent of the rule, licensees should use their existing structural monitoring programs (e.g., those required by other regulations or codes) to the maximum extent practical. Definition of “Standby System or Train” In NUMARC 93-01, standby SSCs of low safety significance must have SSC-specific performance criteria or goals, similar to SSCs of high safety significance. Appendix B “Maintenance Guideline Definitions” to NUMARC 93-01 provides the following definition of “Standby System or Train:” “A standby system or train is one that is not operating and only performs its intended function when initiated by either an automatic or manual demand signal.” Some licensees have improperly interpreted this definition to mean that SSCs that are energized are normally operating. Normally operating SSCs are those whose failure would be readily apparent (e.g., a pump failure results in loss of flow that causes a trip). Standby SSCs are those whose failure would not become apparent until the next demand, actuation, or surveillance. Only those SSCs