Application of noncontact type of ultrasonic flowmeter for high temperature LBE flow

Obayashi, Hironari  ; Yamaki, Kenichi*; Kita, Satoshi*; Ariyoshi, Gen  ; Sasa, Toshinobu   

JAEA developed a non-contact type flowmeter that two ultrasonic sensors were installed on outer surface of a cylindrical-shaped test section. The considerable issue of the realization was multiple reflection of emitted signal in the piping. Furthermore, wettability between LBE and inner surface of the test section was one of the important issue on the ultrasonic technique. To mitigate the multiple reflection, a critical angle as an incident angle not to produce a longitudinal wave on the solid / solid boundary was applied. And fine mirror-finished treatment was applied to the inner surface of the test section to ensure wettability. As a result of experiment at 350 degrees C, the observed correlation value between the non-contact type and the established plug type was 0.9986. Additionally, the developed non-contact type provided its sufficiently stable output during a long-term test more than 1,500 hours.