Electromagnetic Optimization and Preliminary Mechanical Analysis of the CFETR CS Model Coil

The central solenoid model coil of China Fusion Engineering Test Reactor consists of two modules: 1) the inner module made of Nb
₃
Sn and 2) the outer module made of NbTi. This paper describes an optimization procedure for the electromagnetic design of the model coil by means of a Fortran code written for this purpose. The target of the optimization was the reduction of the length of the Nb3Sn cable-in-conduit conductor, needed to produce a peak magnetic field of 12 T. The optimization constraints are: 1) the maximum magnetic field on the NbTi module should be lower than 6 T and 2) the unit length of one Nb3Sn conductor should be shorter than 1 km. Based on the electromagnetic optimization, the engineering scheme of the model coil is determined. The feasibility of the engineering scheme is investigated using ANSYS finite element code. Accordingly, a mechanical analysis of the structure under the Lorentz force at 4.5 K is performed. The analysis results indicate that the present design is reasonable and fulfills the design requirements.