Structural Design and Mechanical Analysis of HTS CICC Made From Twisted Stack Slotted-Core Cable

To meet the parameters of the toroidal field (TF) magnet of the China Fusion Engineering Test Reactor, this article proposes a high-temperature superconducting cable-in-conduit conductor with two support structures composed of six twisted stack slotted-core cables (TSSC), which is designed to target current 100 kA at 4.2 K temperature in a background magnetic field of up to 20 T. Therefore, the enormous transverse electromagnetic load must be considered in the design process to ensure the operation safety and stability of the conductor. The influence of transverse Lorentz force on the cable stress distribution and deformation displacement is analyzed based on finite-element analysis. The improved 2-D numerical model is established to reduce the problem of long computation time so that the mechanical feasibility of the conductor structure can be quickly evaluated. The calculation results show that the outermost layer of the REBCO tapes, where the tape stack is in contact with the solder, is subjected to the highest stresses (less than 35 MPa), and the conductors with two different support structures do not plastically deform under transverse electromagnetic load. The experimental results indicate that the maximum transverse load applied reaches 140 MPa, and the critical current of the TSSC cable does not show any recession, which provides a potential solution for the application of high-field magnets.