Design of Bi-based superconducting current lead for SMES

2.1 kA-class hybrid-type current leads for superconducting magnetic energy storage (SMES) magnets, consisting of conventional gas-cooled copper leads and high-T/sub c/ superconducting (HTSC) current leads, were designed. The HTSC parts of the leads are made of Bi-2223/99.8%Ag0.2%Au tape. For the design, numerical analysis was performed to find an optimum shape factor and an optimum varying rate of the cross-sectional area of HTSC lead which result in minimum refrigeration power consumption, and then the minimum evaporation rate of LHe. In the present study, the main results of the design are presented.