Helium cooling for KSTAR [ Return towards  References  ]

Air Liquide was chosen in 2005 to design and implement the Helium Refrigeration System (or HRS).
This ensures that the Helium is kept at a cryogenic temperature, using a closed loop operating process. With a refrigerating capacity of 9 kW at 4.5 K, it consists mainly of a set of screw compressors that compress the Helium at 22 bars abs with its oil separation system, a cold box containing the cryogenic expansion turbines needed to reduce the temperature of the Helium, a liquid Helium storage tank, a valve box for distributing the Helium to the Tokamak, and a gaseous helium recovery and purification system.

Not only was it manufactured in record time (about 6 months) at the Sassenage workshops, but the 100 metric tons of steel, aluminum and stainless steel were assembled with millimeter precision, an outstanding degree of leak tightness for this technology, and are robust enough to withstand a journey by road and sea lasting 10 weeks.