Novel Low-Cost Method of Manufacturing Nb3Sn Multifilamentary Superconductors with Multiple-Tin-Tube Sources

In order to successfully sustain a fusion reaction, peak magnetic fields on the order of 12-13 Tesla will be required. Magnetic fields of this magnitude can only be accomplished by advanced superconductors such as Nb3Sn. However, the economic success of a fusion machine will depend on further improvements in the cost-performance of the Nb3Sn conductor. This project will develop a novel, low-cost, multiple-tin-tube process as a new manufacturing approach for large-scale Nb3Sn-conductor production. The process will be suitable for the efficient production of larger strands (0.83 mm), consistent with ITER (International Thermonuclear Experimental Reactor) specifications. In Phase I, Cu/Nb composites will manufactured and shaped into sub-elements. These sub-elements will be tin-coated by electroplating, assembled into a precise-fit restack billet tube, and drawn to 0.83 mm diameter. In Phase II, the process will be scaled-up to full production levels. Commercial Applications and Other Benefits as described by the awardee: The improved Nb3Sn conductor should have an immediate benefit for high-field magnet applications. A prototype fusion machine, based on acost effective Nb3Sn conductor, would have enormous economic and social benefits. In addition, the conductor should be applicable to nuclear magnetic resonance (NMR), which has requirements for use in chemical research, biochemistry, pharmaceutical chemistry, polymer science, petroleum research, agricultural chemistry, and medicine.