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

Fusion reactors, which require confinement of a hot plasma at temperatures comparable to that found on the sun, potentially will provide unlimited energy for mankind. In turn, this confinement will require high-field magnets based on superconducting technology. This project will develop and demonstrate an economical Nb3Sn conductor manufacturing process based on multiple-tin-tube (MTT) sources. In particular, sub-elements having a tin core will be replaced by sub-elements having a tin coating. Greater current density and lower magnetization losses are expected. Conductor cost savings of ~20% to 30% will be realized in comparison to the current state-of-the-art internal-tin-core Nb3Sn process. In Phase I, the MTT process was developed and prototype Nb3Sn conductors were fabricated. In Phase II, the MTT process will be optimized for intermediate-size billets. A scaled-up prototype conductor will be produced. The material will be made available to DOE national laboratories for testing purposes, and for building prototype cables and test magnets. Commercial Applications and Other Benefits as described by the awardee: The new MTT Nb3Sn conductor should have an immediate benefit for high field magnet applications. In addition to the fusion application, the material should have application to nuclear magnetic resonance (NMR), which is on the verge of technological explosion with requirements for uses in chemical research, biochemistry, pharmaceutical chemistry, polymer science, petroleum research, agricultural chemistry, and medicine.