Cryogenics

The cryoplant supplies supercritical or gaseous He to superconducting magnets, current leads, feeders, various cryo-panels, and the thermal shields.

Refrigerator demand is 7 kW at 4.5K. The plant has four main parts:
•  a helium refrigerator, composed of a warm compressor, oil/water removal system, pressure control, gas management system, refrigerator coldbox, and a local control system - the coldbox supplies 80K helium for thermal shields, 50K helium for high temperature superconductor current leads, and supercritical helium (4.4K) for the magnet system;
•  an auxiliary cold box to supply TF and PF coils at 4.4K and the cryopump at 3.7K;
•  a gas storage and distribution system composed of warm helium storage, liquid He and N storage, cryogenic transfer lines, and warm interconnecting pipework;
•  auxiliary equipment such as pneumatic and vacuum systems for the different cold boxes and cryolines.

A new compressor building will be built in the west side vacant area of the JT-60 experimental building to limit the impact of noise from the compressors. The cold box, liquid He tank, pre-cooler and some other devices will be installed into the refrigerator hall neighbouring the JT-60SA torus hall.