Nuclear power plant, method for monitoring thermal fatigue of water supply nozzle, and method for operating nuclear power plant

摘要

PPROBLEM TO BE SOLVED: To provide a nuclear power plant capable of enhancing an operation rate. PSOLUTION: A monitor 42 has a computing device 43 and a determination device 44. A temperature detector 41 measures a cooling water temperature in the vicinity of a water supply nozzle 12 provided in an RPV 3. The computing device 43 input with a temperature measured value calculates a non-stationary stress SBalt/SBand a cumulative damage coefficient Uf. The determination device 44 determines whether respective calculated values satisfy respective set values thereof or not. For example, a controller 48 increases an opening degree of an extraction steam flow regulating valve 40, when the cumulative damage coefficient Uf is 1 or more, to increase a water supply temperature. The computing device 43 predicts the cumulative damage coefficient Uf in the future. The determination device 44 determines whether the predicted cumulative damage coefficient Uf is less than 1 or not. The controller 48 increases the water supply temperature, for a period from a time point when the predicted cumulative damage coefficient Uf comes to 1, up to the stop of the plant, when the time point of reaching 1 is before the next periodic inspection. PCOPYRIGHT: (C)2009,JPO&INPIT