1-D Electromagnetic and Thermal-Hydraulic Analysis of the Superconducting Proposal for the CS Magnets of FAST

FAST (Fusion Advanced Studies Torus), the Italian proposal of a Satellite Facility to ITER, has been the object of an intense re-design activity aimed at verifying the feasibility of a superconducting solution for its magnet system. One of the most difficult and critical obstacles is represented by the central solenoid (CS) magnet, due to the rapid variation of the current and magnetic field (up to 40 T/s) foreseen so far in the reference scenario. The associated losses induced in the CS magnets should be dissipated by the flow of helium that cools the conductors. Nonetheless, even the losses depend on the conductor design, therefore, not only the thermal-hydraulics of the Cable-in-Conduit Conductors (CICCs) but also the strand properties, should be considered to identify the best design capable to sustain the transient in the CS magnets, keeping the scenario originally foreseen for the resistive configuration of the machine unaltered. The present paper discusses the electromagnetic and thermal-hydraulic behavior of the CICC design envisaged for the FAST CS magnet in the H-mode scenario, and identifies the possible strategies to make a superconducting solution sustainable.