Design and Test Results of Joints for ITER TF Feeder Current Leads and Superconducting Busbars

The Toroidal Field (TF) coil feeder for the International Thermonuclear Experimental Reactor (ITER) contains a pair of NbTi superconducting cable-in-conduit conductor (CICC) busbars carrying current up to 68 kA. The superconducting busbar is divided into different segments. Several joints are used to connect them electrically. In order to minimize the heat load of the joints to the cryo-system of the feeder, the DC resistance of the joint connection must be lower than 2 ${\rm n}\Omega$ , and the pressure head loss of joint must be also low enough. Meanwhile, the structure of joint should be convenient for assembly on site. In the baseline design, the ‘Twin-Box type’ joint, which was made by copper-stainless steel bimetal plate, has been developed by the ITER Feeder Group in China. Two full scale joints for ITER feeder were manufactured, connected with the 68 kA/52 kA high temperature superconducting current leads (HTSCLs), and tested to the ITER TF feeder operation condition at CASIPP. This paper describes the design and manufacturing procedure of the joint, and presents the experimental results of the DC electrical behavior and pressure head loss of the joint.