Performance of highly flexible sub-cable for REBCO Cable-In-Conduit conductor at 5.8 T applied field

Due to the high current capability and excellent flexibility, High Flexible REBCO Cables (HFRC) have emerged as an important candidate for composite high-temperature superconducting conductors. The REBCO six around one Cable-In-Conduit Conductor (CICC) concept has been designed for application in the Central Solenoid (CS) coil of the China Fusion Engineering Test Reactor. In the application of fusion devices, the performance of CICC under electromagnetic (EM) loading and thermal stress is very important for reliable and economic operation. Therefore, a 1.22 m long sub-cable with HFRC design for CICC was manufactured and tested at 4.2 K in a background magnetic field up to 5.8 T. The aim is to investigate the stability of the current-carrying properties of the HFRC cable under electromagnetic and thermal cyclic loading. The test results show that the critical current (Ic) of the HFRC cable reached 17.3 kA in a background magnetic field of 5.8 T at 4.2 K. Furthermore, no performance degradation was observed after 24 cycles of 80 kN/m peak load with a background field of 5.8 T and 8 warm-up-cool-down cycles between 77 K and room temperature. The test results provide a good basis for the development of full-size conductors in future magnet applications.