Development of plug-in type ultrasonic flowmeter for lead-bismuth spallation target system

溶融鉛ビスマス核破砕ターゲットシステム用プラグ液浸型超音波流量計の開発

大林 寛生  ; 平林 勝; 佐々 敏信   ; 荒 邦章 

Obayashi, Hironari; Hirabayashi, Masaru; Sasa, Toshinobu; Ara, Kuniaki

The purpose of this study is to develop a long lasting and a reliable flowmeter for a lead-bisbuth eutectic alloy (LBE) target system. To measure the flowrate of high temperature liquid metal, JAEA has been developed a special flow-monitoring device using ultrasonic. To overcome the limitation of temperature, we tried to apply the lithium niobate crystal. It is also known that the output signal from lithium niobate is poor. So, we made modification to the sensor arrangement to realize the effective signal transmission and the developed system works poor signal condition hence it can use lithium niobate. And we realizes a very high heat resistance up to 500C. To increase the wettability, high chromium steel was selected as a plug into LBE. As a result of competitive examination with calibrated electromagnetic flowmeter (EMF), the measured value obtained by ultrasonic flowmeter showed good agreement with the data taken by EMF and theoretical flowrate determined by electromagnetic pump. The durability test over 4,500 hrs was also performed. As a result, our developed ultrasonic flowmeter measuring system satisfactory results with error of less than 3% in high temperature and flowing LBE environment.