Good practices for effective maintenance to manage aging at NPPs

The Nuclear Regulatory Commission's Office of Nuclear Regulatory Research is sponsoring this effort to study maintenance as it relates to aging, under the Nuclear Plant Aging Research (NPAR). Maintenance is the primary means of combating and correcting the effects of aging degradation at nuclear power plants. Maintenance effectiveness directly affects the safety of nuclear power plants. Several recent plant events have shown that improper maintenance or a lack of maintenance can be a significant contributory cause of plant incidents (e.g., transients at Rancho Seco and Davis Besse, and the Salem anticipated transient without scram event). In these, and other events, safety related plant equipment functions have been impaired by poor maintenance practices or a lack of maintenance on the specific equipment or in ancillary equipment that affects the ability of the safety related equipment to function. In some cases, the ancillary equipment has been nonsafety-related equipment, or balance-of-plant equipment that has not received adequate maintenance attention. In addition to the potential for causing safety significant plant transients, poor or lacking maintenance may allow the licensing basis of the plant to be eroded without detection. In some cases, time-related aging degradation of equipment that has not been detected, corrected or managed by the maintenance program has been a significant contributory factor. The NPAR program has developed significant information on aging degradation, detection, mitigation, and correction practices for safety-significant structures, systems and components that can be factored into maintenance programs and their effectiveness