Lessons Learned From Maintenance Rule Baseline Inspections

This report summarizes the lessons learned from 68 maintenance rule (MR) baseline inspections (MRBIs) conducted at plants holding operating licenses in accordance with Title 10, Part 50, of the Code of Federal Regulations (CFR) and 3 MRBIs conducted at plants with decommissioning certifications in accordance with 10 CFR 50.82(a)(2). The MRBIs were conducted between July 15, 1996, and July 10, 1998. In general, these MRBIs revealed that licensees implemented the requirements of the maintenance rule, 10 CFR 50.65, by following the guidance in NUMARC 93-01, "Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," as endorsed by NRC Regulatory Guide 1.160, "Monitoring the Effectiveness of Maintenance at Nuclear Power Plants." Additionally, licensees effectively determined which structures, systems, and components (SSCs) at each site were within the scope of the MR. The use of expert panels was effective in determining which SSCs were risk significant. The results of the MRBIs also indicated that several expert panels performed other MR activities that exceeded the guidance in NUMARC 93-01. When setting goals or performance measures (criteria) in accordance with 10 CFR 50.65(a)(1) or (a)(2), respectively, most licensees considered risk insights from the probabilistic risk assessments (PRAs). However, early MRBIs revealed that some licensees did not have adequate technical justification for deviating from SSC reliability and availability assumptions in the PRAs when establishing goals or performance criteria and did not adequately assess planned and emergent maintenance activities. Most licensees' individual self-assessments were a MR program implementation strength. Most licensees also established reasonable plans and methods to periodically evaluate the effectiveness of equipment performance monitoring and preventive maintenance, including the balance between reliability and availability. Read more