Design study of HTS current lead using reinforced Bi-2212 tubular bulk

Current leads using HTS material have been developed for large scale superconducting magnet system. Tokai University and NIFS have been investigating characteristics of Bi-2212 tubular bulk which was prepared by a diffusion process. 8 kA of the maximum transport current was achieved at 4 K with the bulk size of 38 mm/30 mm in outer/inner diameters and 200 mm in length, respectively. The tubular bulk was reinforced by using alumina fiber and epoxy resin so that a mechanical strength was improved. Although further improvement was needed for practical use, this type of HTS bulk has a potential for flexible design since Bi-2212 layer can be reacted on the surface of any shapes of substrate. In this paper, a design of a current lead using this type of Bi-2212 tubular bulk was studied with conventional heat exchanger part and low-T_c superconducting bus line.