Thermal–hydraulic analysis of the cool-down for the ITER magnets

• A 3D transient model has been applied to simulate cool-down of ITER magnet system.
• For cool-down to 6 K, we embed the refrigerator model in cool-down model.
• An improved cool-down strategy for ITER magnet system is found.
• The results show that gradual cool-down to 80 K can be achieved in 500 h.
• The results show that fast cool-down to 6 K can be achieved in 250 h.

A 3D time-dependent cool-down simulation for the ITER magnet system has been performed. The total cold mass of the magnet system is about 10,130 ton, namely 18 Toroidal Field Winding Packs and their mechanical Cases, 6 Poloidal Field coils, Central Solenoid and a set of Correction Coils. All ITER coils are made from cable-in-conduit conductor superconductors. This paper presents the simplified flow scheme of the magnet system and the simulation models. The simulated temperature evolutions of entire processes of cool-down are showed. The functions of the inlet temperature for cool-down are summarized. The simulation results indicate that it is possible to cool down the entire ITER magnet system to 6 K within 750 h.