Development and Manufacturing of Bronze-Processed Ta-Added Nb3Sn Wires for the ITER.

Development work to produce a high-performance Nb3Sn superconducting wire for the center solenoid coil of the ITER was carried out. The effects of concurrently adding Ti and Ta to bronze-processed Nb3Sn wires were examined. In addition, a high-Sn-concentration bronze matrix was applied. Then, the relation between hysteresis loss and filament diameter was examined. Moreover, the cause of wire breakage during processing was elucidated. As a result, a reliable manufacturing process for high-performance Nb3Sn superconducting wire was established.