抄録
At the Fukushima Dai-ichi Nuclear Power Station (NPS), investigations of NPS condition are conducted to retrieve fuel debris to achieve the decommissioning. In this study, we focused on the ultrasonic measurement technique for the survey, because ultrasonic technique can overcome the environment such as a cloudy and highly-dosed environment. However, when we use ultrasound in air, the attenuation of ultrasound in air is large. Therefore, 3D measurement technology using parametric ultrasound source is expected to long distance measurement. Because it’s characteristics are lower attenuation in the air and lower side robe causing noise signal compared to single frequency ultrasound. For measurement application inside of nuclear reactor using this technique, we investigated the measurable length and conducted measurement of the shapes of simulated the fuel debris models under mist environment.
