Abstract: A jet pump which can restrain self-excited vibration in a connection portion between an inlet mixer pipe and a diffuser pipe without inhibiting a structural deformation due to thermal expansion and the like includes a slip joint structure connecting the inlet mixer pipe and the diffuser pipe to each other by inserting the inlet mixer pipe into an upper end opening of the diffuser pipe with a clearance left therebetween; and a self vibration damping structure configured such that when the clearance defined by an outer pipe wall of the inlet mixer pipe and an inner pipe wall of the diffuser pipe is widening or narrowing due to vibration of the inlet mixer pipe or the diffuser pipe, a flow path resistance inside a clearance flow path for pumped coolant water defined by the clearance is not smaller than a fluid inertia force all over the clearance flow path.

Abstract: The present invention provides a vibration monitoring apparatus that monitors vibration of a jet pump disposed in a reactor pressure vessel using ultrasonic wave, including: an ultrasonic sensor that is attached to an outside the reactor pressure vessel, and transmits and receives ultrasonic wave; a reflector that is mounted on a surface of a riser pipe of the jet pump, and includes a planar reflecting surface that can reflect ultrasonic wave; and a signal processing unit that performs signal processing of the ultrasonic wave transmitted by the ultrasonic sensor, reflected by the reflecting surface of the reflector, and received by the ultrasonic sensor, and measures a vibration amplitude of the riser pipe and calculates a vibration waveform.

Abstract: The present invention has an object to provide a jet pump, which can restrain self-excited vibration in a connection portion between an inlet mixer pipe and a diffuser pipe without inhibiting a structural deformation due to thermal expansion and the like. The jet pump includes: a slip joint structure connecting the inlet mixer pipe and the diffuser pipe to each other by inserting the inlet mixer pipe into an upper end opening of the diffuser pipe with a clearance left therebetween; and a self vibration damping structure configured such that when the clearance defined by an outer pipe wall of the inlet mixer pipe and an inner pipe wall of the diffuser pipe is widening or narrowing due to vibration of the inlet mixer pipe or the diffuser pipe, a flow path resistance inside a clearance flow path for pumped coolant water defined by the clearance is not smaller than a fluid inertia force all over the clearance flow path.

Abstract: The present invention provides a vibration monitoring apparatus that monitors vibration of a jet pump disposed in a reactor pressure vessel using ultrasonic wave, including: an ultrasonic sensor that is attached to an outside the reactor pressure vessel, and transmits and receives ultrasonic wave; a reflector that is mounted on a surface of a riser pipe of the jet pump, and includes a planar reflecting surface that can reflect ultrasonic wave; and a signal processing unit that performs signal processing of the ultrasonic wave transmitted by the ultrasonic sensor, reflected by the reflecting surface of the reflector, and received by the ultrasonic sensor, and measures a vibration amplitude of the riser pipe and calculates a vibration waveform.

Abstract: The present invention includes: a plurality of sensors (strain gauge, accelerometer, ultrasonic sensor) that measure data on vibration at a plurality of measurement points on a jet pump; a vibration analysis unit that performs vibration analysis using a numerical structure analysis model of the jet pump, and calculates a vibration state of the jet pump; and an evaluation unit that estimates and evaluates a vibration state in each position on the jet pump using the numerical structure analysis model when an analysis result in a position corresponding to the measurement point by the vibration analysis of the vibration analysis unit matches the data measured by the sensors.