Present status of Japanese tasks for lithium target facility under IFMIF/EVEDA, 3; Engineering design and fabrication of contact-type liquid level sensor

Kanemura, Takuji; Kondo, Hiroo; Furukawa, Tomohiro  ; Yamaoka, Nobuo*; Suzuki, Sachiko*; Hoashi, Eiji*; Horiike, Hiroshi*; Nakamura, Kazuyuki 

In the Engineering Validation and Engineering Design Activities (EVEDA) of the International Fusion Materials Irradiation Facility (IFMIF) which is one of the Broader Approach (BA) activities, the thickness variation of the liquid lithium (Li) jet simulating the IFMIF Li target is planned to be measured in EVEDA Li Test Loop (ELTL). A contact-type liquid level sensor which will be utilized for thickness measurement was developed. The sensor can detect the contacts between a probe and Li, and by analyzing the contact signals, variation characteristics such as average jet thickness and an amplitude distribution can be obtained. One of the key points of development is to drive the probe by 0.1 mm step with repeat accuracy of 0.01 mm under vacuum condition of 10Pa. To satisfy such a requirement, a powerful motor which has good positioning performance and a friction-reduced ball screw were selected. It is finally confirmed that the sensor performance satisfies the specification.