Reactor pressure vessel (RPV) steels are subjected to neutron irradiation that can lead to loss of fracture toughness. One of the critical issues for RPV structural integrity is related to the pressurized thermal shock (PTS) event. Risk assessment is important for safety evaluation and maintenance planning of a nuclear power plant. In this study, a new method was developed to assess a failure risk of RPV at PTS event for the risk-based maintenance. The failure risk was caused by fluctuations of stress...
英字タイトル:
Risk-based Optimization of Reactor Pressure Vessel Maintenance

The structural integrity of a reactor pressure vessel (RPV) is important part of nuclear power plant safety. Pressurized thermal shock (PTS) takes place when the emergency core cooling system (ECCS) is operated and the coolant water is injected into the RPV due to a loss-of-coolant accident (LOCA). With the neutron irradiation, PTS loading may lead a RPV to fracture. In the present study, optimization of RPV maintenance is considered, where two different attempts are made to investigate the RPV integri...
英字タイトル:
From the Viewpoint of Maintenance, the Probabilistic Integrity Evaluation of Reactor Pressure Vessel

In Japan, the government decided that nuclear power was used as one of the energy sources for base load energy. Nuclear power plants are required more safety. The plant safety have kept since the start of operation due to the maintenance. Since the maintenance plan should be continued improving, there is still issues for improvement in the plan. In this study, we systematize the methods of the plant maintenance. We review the maintenance plan of reactor pressure vessel and fuel cladding tube and indic...
英字タイトル:
Advanced maintenance methodology was developed for the keeping integrity of reactor pressure vessel