| 摘要 |
PROBLEM TO BE SOLVED: To easily attach a transmitting acoustic sensor and a receiving acoustic sensor which are used for a leak monitoring operation by a method wherein acoustic waves are generated directly, by an electromagnetic means, on the surface of a container in which a medium to be monitored is sealed and the acoustic waves are received by an electromagnetic means. SOLUTION: An electric signal which is generated intermittently by an acoustic-wave generation controller 200 is converted into acoustic waves by a transmitting acoustic sensor 11a to a transmitting acoustic sensor 11c so as to be sent out into an SG container drum 7. The acoustic waves are detected by a receiving acoustic sensor 12a to a receiving acoustic sensor 12c so as to be converted into electric signals, and a change due to a leak in output signals of the receiving acoustic sensors 12a to 12c is detected by a leak detector 300. Sodium as a high-temperature fluid and water as a low-temperature fluid are passed through the inside of the SG container drum 7, and both are separated by the wall of a heat exchanger tube 3. Since the water inside the heat exchanger tube 3 is at a high pressure, the water is leaked to the side of the sodium when a crack or the like is generated in the heat exchanger tube 3. As a result, hydrogen air bubbles are generated due to a chemical reaction. The hydrogen air bubbles attenuate the acoustic waves which are propagated inside the SG container drum 7, and the existence of a leak is detected on the basis of a change in the propagation attenuation of the acoustic waves.
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