Under sodium visualization technique using ultrasonic and its application

Takahashi, Keita; Yamaguchi, Toshihiko ; Saito, Junichi  ; Ueda, Masashi ; Nakaishi, Sumitaka*

In order to visualize the phenomenon under opaque liquid sodium, which is coolant of fast reactors, we tried to made an ultrasonic visualization device. A buffer rod was implemented to cope with high temperatures, and as a result of improvements in frequency, shape, etc., a resolution of 0.5 mm was obtained under sodium. Using this device, the transmittance of ultrasonic waves at the interface between liquid sodium and stainless steel was investigated. As the result, it was confirmed that the temperature of sodium and the roughness of the surface of stainless steel affect the transmitting behavior of ultrasonic waves.