Development program of a 60 kA current lead using high temperature superconductors

The use of high temperature superconductors in current leads to reduce the refrigerator power consumption has been investigated in the last few years by many groups. Potential candidates are Y-123 and Bi-2212 bulk material as well as Bi-2223 tapes sheathed with an Ag/Au alloy. In the frame of the European Fusion Technology Programme, FZK Karlsruhe and CRPP Villigen have started a development program for design and construction of a 60 kA current lead for the ITER Toroidal Field Coils. The task composes of three parts: material selection based on test results of 1 kA current leads, construction and test of 10 and 20 kA leads using the selected HTSC material giving proof of the modularity and scale-ability of the design, and finally construction and test of a 60 kA current lead which will replace an existing conventional lead in the superconducting coil test facility TOSKA at FZK. The paper describes the status of the development program. Experimental results of the first step and a first approach of the realisation of the 10 kA HTSC lead are given.