Development of a 10 kA-class high-Tc superconducting bus bar

In order to investigate the applicability of high-Tc materials for bus lines between magnets and power supplies in a fusion reactor, a 10 kA-class bus bar has been fabricated and tested at 77 K. The bus bar consists of 10 conductor units which are prepared by stacking 250 Bi-2223 superconductor tapes which are made by a powder-in-tube method. The 10 conductor units are installed into the grooves on a decagonal FRP structure and the current for each unit conductor is carried in the opposite direction for the current of neighboring unit conductor to reduce the self magnetic field. The bus bar was immersed in liquid nitrogen and was successfully operated up to 10.3 kA with the alternative go-and-return structure.<>