Design of the cryogenic loop for the superconducting toroidal-field magnets of the Divertor Tokamak Test

The design of the cryogenic circuit for the toroidal field magnets has a relevant role in the overall costs of the DTT cryogenic plant (or cryoplant), hence numerical tools can be useful to investigate and to compare different configurations for the TF cooling circuit in support of the selection of the most suitable one. The system-level cryogenic circuit module of the validated thermal-hydraulic 4C code is adopted in this work to model the DTT TF cooling system. At first, the model of the reference circuit layout is implemented and simulated during the plasma pulsed operation of the DTT machine, highlighting the necessity to reduce the heat load transferred to the refrigerator due to the large power consumption of the cold compressor. In view of the above, different TF circuit layouts and optimization strategies are presented, including mitigation strategies for the smoothing of the peak heat load to the refrigerator, leading to a reduction of the cold compressor power up to the 66% with respect to that computed for the reference TF cryogenic circuit layout.