Manufacture and Testing of Pre-prototype HTS Twisted Stack Slotted-core Cable

REBCO, the second generation of high-temperature superconducting (HTS) tape, has broad application prospects in nuclear fusion and high-field magnetic devices due to its excellent critical current density, superior mechanical properties, and electromagnetic characteristics. The REBCO-based six around one Cable-In-Conduit Conductor (CICC) for application in the toroidal field magnet of the China Fusion Engineering Test Reactor (CFETR) has been proposed. In this paper, two 1-m-long preliminary Twisted Stack Slotted-core Cables (TSSC) stacked by REBCO and copper tapes were fabricated. Subsequently, the critical current characteristics were tested at 77 K and self-field, and compared with the results simulated by the self-consistent model. The calculated values of the critical current are in high agreement with the experimental values, which proves the accuracy of the finite element model. The results of cross-section scanning after cutting the samples indicate that the gaps are uniformly filled with solder and the fabrication process is performed reliably. This study is of great importance for future applications of high-field fusion magnets.