Implementation of maintenance rule for structures Original Research Article

The maintenance rule, 10 CFR 50.65, ‘Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants’, was published by the Nuclear Regulatory Commission (NRC) in the Federal Register (56 FR 31324) on July 10, 1991. The rule became effective on July 10, 1996, giving nuclear power plant licensees 5 years to implement it. During 1994–1995, NRC staff visited nine nuclear power plant sites to observe licensees’ preparations for implementation of the rule. The teams found that most of the licensees had not established goals, or performance criteria for monitoring structures at their sites. The licensees contended that the structures were inherently reliable and required no monitoring under the maintenance rule. On the basis of earlier site visits performed by NRC staff to assess the condition of structures, the NRC staff could not accept this contention, and clarified its position in Revision 1 of Regulatory Guide 1.160, ‘Monitoring the Effectiveness of Maintenance at Nuclear Power Plants’. This paper discusses the applicability of the maintenance rule criteria for structures and its usefulness in ensuring that the structures, systems, and components within the scope of the maintenance rule are capable of fulfilling their intended functions. Also discussed are the aspects of maintenance rule efforts that could be useful for license renewal applications.