REBCO Coated Conductor Cables for Fusion Magnets

The feasibility for fusion as a practical energy source needs to be enhanced significantly by removing some of the restrictions that low-temperature superconductors put on the fusion magnet systems. This can be done by using high-temperature superconductors, allowing for much larger temperature margins, a higher magnet performance and less mechanical degradation during operation. There are currently no feasible methods to construct HTS cables that have the performance and current homogeneity needed for fusion magnets. Advanced Conductor Technologies will develop high-temperature superconducting `Conductor-on-Round-Core cables, invented by the Principal Investigator, for use in fusion magnets. These cables will have a homogenous current distribution at high current ramp rates, a stable operation at elevated temperatures and high magnetic fields, and will be mechanically robust. During Phase I we have demonstrated the feasibility of Conductor-on-RoundCore cables for fusion applications. Weve shown, both analytically and experimentally, that the current distribution in these cables remains homogeneous at current ramp rates as high as 68,000 amperes per second. We also developed a cable with a record current carrying performance of 5,021 amperes in a background field of 19 teslas. During Phase II we propose to construct a six-aroundone cable, capable of carrying a current of over 60,000 A, by bundling six Conductor-on-RoundCore cables around a central cooling tube. The cable will be optimized to withstand the large forces during operation and to allow for operation at elevated temperatures. We will test the cable in flowing helium gas and at magnetic fields as high as 12 teslas. Commercial Applications and Other Benefits: High-temperature superconducting magnet cables will enable more practical fusion magnets, the next generation of very high field scientific magnets, and magnets for grid energy storage and for proton cancer treatment facilities.