Study of Supercritical Helium Circulation Pump for a Forced-Flow Cooled Magnet Using CICC

A fusion reactor, such as International Thermonuclear Experimental Reactor, should require a large scale forced-flow cooled cable-in-conduit conductor magnet. Such a magnet is operated by forced-flow cooling with a large amount of supercritical helium. A cryogenic pump is effective and reasonable to achieve such a forced-flow cooling for the magnet. A thermodynamic study shows a merit for the cryogenic pump compared to a conventional helium system in which the helium refrigerator supplies supercritical helium through the Joule Thomson line if the adiabatic pump efficiency of the cryogenic pump is more than 60%. A technical base for developing a large scale cryogenic pump is already established through continuous cryogenic pump developing at Japan Atomic Energy Research Institute as reviewed in the paper.