抄録
Predictive and preventive maintenance management is increasingly of imporatance for the safe operation of nuclear power plants. Utilities has been imporoved the maintenance mangement system based on design base degradation and operation experience. Recently, US NRC introduced proactive approach due to identiy future degradation of materials in light water reactors. Conventional reactive approach based on predictive and preventive maintenance management has maintained the safety of opetrating plants, but has proved to be an inefficient of managing materials degradation issues since Davis-Vesse incident. In order for the realization of more safe operation to be successsful, it is essential that mitigation of "out of scope" incidents. In this paper, one of case that is proactive approch for maintenance based on degradation experience is introdued.
