J0420103 地下埋設タンクの健全性モニタリングのためのAEセンサの開発

抄録

Underground storage tanks have passed for many years after they were installed. Therefore, corrosion progresses occur on the wall of tanks and cause leak accidents. These tanks are generally monitored and checked by pressure tests or observation tests. However, it is difficult to detect the corrosion before tank leakage occurred at present. We employ the acoustic emission (AE) method to monitor the corrosion by detecting breakage and exfoliation of the rust. Immersion-type sensor for monitoring underground storage tank was developed using optical fiber sensor and rectangular sensor box. In this study, elastic wave propagated in underground storage tank composed of gas-liquid phase portion and outer wall was simulated by using the fmite-difference time-domain (FDTD) method. The sensor shape was determined by using the result of simulation. It was considered that optical fiber sensor should be mounted on the upper and lower parts of the sensor box to detect signals from side wall of the tank, and on the bottom parts of sensor box to detect signals below the sensor.