The DTT cryogenic system provides supercritical Helium at three different temperatures: 4.3K, for the superconducting magnets, cold structures and cryopump panels; 50K, for the High Temperature Superconducting current leads; finally, 80K, for the thermal shields. The overall cryogenic capacity is estimated around 11 kW equivalent power at 4.5K.

The DTT cryogenic system (see figg. 1 and 2) includes: Helium and Liquid Nitrogen storage tanks; the Helium Compression Station; a Refrigerating Cold Box, housing the main components to refrigerate the helium (LN2 pre-cooling, heat exchangers, turbines); an Auxiliary Cold Box (containing a liquid helium bath (at 4.2K), acting as a damper to handle the variable loads, and the cold circulators; the Cryogenic Valve Boxes and the cryo-distribution network.

A collaboration agreement with the CEA (French Alternative Energies and Atomic Energy Commission) was activated in February 2023 and recently concluded its first phase providing important contributions to identify the conceptual design and provide the technical documentation for the tender of the cryogenic system supply

Figure 1: Layout of the DTT cryo-distribution system.

Figure 2: Layout of the overall DTT cryogenic system (pictures are taken from similar plants).