Patent Number: 
Section: claims

1. A nuclear reactor vibration surveillance system comprising:a first ultrasonic transducer for transmission which is arranged on the outer surface of a reactor pressure vessel and is configured to convert a transmission signal into an ultrasonic pulse signal and allow the ultrasonic pulse to be transmitted to a reactor internal component;an ultrasonic transmitter which is electrically connected to the first ultrasonic transducer and is configured to transmit the transmission signal;a second ultrasonic transducer for reception which is arranged separately from the first ultrasonic transducer on the outer surface of the reactor pressure vessel and is configured to receive a reflected ultrasonic pulse, which is transmitted by the first ultrasonic transducer and reflected by the reactor internal component, and to convert the received reflected ultrasonic pulse into a reception signal;an ultrasonic receiver which is electrically connected to the second ultrasonic transducer and is configured to receive the reception signal;a signal processor which is electrically connected to the ultrasonic transmitter and ultrasonic receiver and is configured to input a signal to the ultrasonic transmitter and receive a signal from the ultrasonic receiver so as to apply signal processing to the signal; anda display unit which is configured to display vibration information of the reactor internal component obtained as a result of the signal processing by the signal processor. 2. The nuclear reactor vibration surveillance system according to claim 1, wherein the first ultrasonic transducer is configured to change the incident angle of the ultrasonic pulse. 3. The nuclear reactor vibration surveillance system according to claim 1, wherein the second ultrasonic transducer is configured to change the reception angle of the ultrasonic pulse. 4. The nuclear reactor vibration surveillance system according to claim 1, wherein the first ultrasonic transducer is configured to change the incident angle of the ultrasonic pulse, and the second ultrasonic transducer is configured to change the reception angle of the ultrasonic pulse. 5. The nuclear reactor vibration surveillance system according to claim 1, wherein the signal processor performs the frequency analysis for the received signal to calculate the original frequency of the reactor internal component which have no extraordinary frequency, and the display unit displays the temporal change of the difference in frequency.