Development of long-length CORC® cables and cable-in-conduit-conductors for compact fusion reactors

The next-generation low-inductance magnets generating magnetic fields exceeding 14-20 T at 20 K for fusion applications require flexible, high-current high temperature superconducting (HTS) cables that can be manufactured in long lengths. Such cables are currently not available. Advanced Conductor Technologies proposes to develop high-current (20-80 kA) Conductor on Round Core (CORC®) cables wound from HTS tapes that can be produced in long lengths for fusion magnet applications. During the Phase I program, CORC® cables and highly transposed cable-in- conduit-conductors (CICC) will be developed that allow straightforward manufacturing at long lengths with the mechanical resilience needed for compact fusion reactors. The technology will be developed to wind long CORC® cables from HTS tapes that contain tape-to-tape joints and use current sharing between tapes to enable cable lengths that are independent of HTS tape single piece lengths. Several CORC® cables containing tape-to-tape joints will be manufactured and their critical current performance will be evaluated as a function of bending and axial tensile load, and their thermal stability will be measured at 20 – 40 K using helium gas cooling. Several methods to manufacture transposed CORC®-CICC at long lengths will be developed, in which the CORC® conductor is provided with sufficient mechanical support against the high Lorenz forces during operation. During Phase II, longer CORC® cables will be manufactured, wound into small coils, and their performance tested. Longer CORC®-CICC will be manufactured using at least one of the approaches developed during the Phase I program, and their performance tested in relevant background magnetic fields. If successful, the program will result in long-length CORC® cables, and highly transposed CORC®-CICC needed to make compact fusion reactors a reality. Long-length CORC® cables and CICC will enable next generation of compact fusion magnets for energy generation, high-energy physics magnets, gantry systems for proton cancer treatment facilities, and scientific magnets. These conductors will also benefit power transmission and magnetic energy storage systems for use in the power grid and within the Department of Defense.