Electromagnetic Design and Challenges for 14 T High-Tc Toroidal Field Superconducting Magnet for CFETR

The design work of the China Fusion Engineering Test Reactor (CFETR) was started in 2012. Related concept design work for its superconducting magnet system was carried out in the past years. In order to get higher plasma operation parameters, the system was optimized with the major radius (R) of 7.2 m, the minor radius (r) of 2.2 m, and the plasma center magnetic field ($B_{t}$) of 6.5 T. With these higher parameters, the fusion power may exceed 1 GW and the maximum magnetic field of the toroidal field superconducting magnet system will reach to 14.3 T. Due to the fact that the performance of the Nb3Sn strand used for ITER project is very difficult to be applied for such a high field of CFETR, new cable-in-conduit conductors (CICC) structure and conductor design work become the key point of CFETR. This paper illustrates the design and electronic magnetic analysis work of the toroidal field (TF) coils of CFETR. In addition, such high operation current and magnetic field bring to huge electromagnetic force, which will cause lots of challenges for the design work of the TF coil such as the stability margin, mechanical safety, and so on. It is not easy to solve all the issues for such a big superconducting coil for the fusion device in a short time, but we hope the analysis results and database can be good references for the next step R&D work.