Development of High Performance Nb3Sn Conductor for Fusion and Accelerator Applications

While the highest field performance is a primary goal of the conductor in the next generation of particle accelerators, emphasis has been focused mainly on the increase in current carrying capacity. The conductor needed for fusion application, however, requires much lower magnetization limit along with a critical current as high as possible. The upgraded strand specifications for the International Thermonuclear Experimental Reactor (ITER) and particle accelerator applications require further improvement of current density at little expense of ac loss or effective filament diameter. A conductor designed to meet such requirements has been fabricated. The effect of heat treatment condition on its properties was investigated to develop an optimized reaction condition. Significant efforts have been made to explore the sub-element design and configuration of the strand to ensure minimum hysteresis of the wire. An attempt was also made to scale up the restack assembly unit for mass production.