Abstract: A vibration measuring apparatus for nuclear reactor internal structure includes a holder which has an opening contact on a surface of a pressure vessel of a nuclear reactor; a vibrator accommodated in the holder so as to transmit or receive an ultrasonic wave; a couplant with which the holder is filled up; and, a bias component applies a biasing force to the vibrator in the direction of the opening; The couplant is a solid state of metal material at normal temperature and change to liquid stage by heat transfer from the pressure vessel.

Abstract: A vibration measuring apparatus for nuclear reactor internal structure includes a holder which has an opening contact on a surface of a pressure vessel of a nuclear reactor; a vibrator accommodated in the holder so as to transmit or receive an ultrasonic wave; a couplant with which the holder is filled up; and, a bias component applies a biasing force to the vibrator in the direction of the opening; The couplant is a solid state of metal material at normal temperature and change to liquid stage by heat transfer from the pressure vessel.

Abstract: A method for inspection and maintenance of an inside of a nuclear power reactor is provided, which can perform positioning of a remote operated vehicle relative to an inspection target surface in a nuclear power reactor in a short period of time with high accuracy, and enhance the positioning repeatability for the remote operated vehicle, thereby enabling performance of the inspection and maintenance for the inspection target surface securely and satisfactorily. For the inspection or maintenance for the inspection target surface 1a in a nuclear power reactor by using the remote operated vehicle 30, a detection mark 3 is formed in advance by providing a notching, marking, punching or engraving process to the inspection target surface 1a before performing inspection or maintenance of the inside of the nuclear power reactor by using the remote operated vehicle 30. Then, the remote operated vehicle 30 is driven to move in the nuclear power reactor filled with water.