CRYOGENIC HELIUM PUMP SYSTEM FOR THE DEVELOPMENT OF SUPERCONDUCTING MAGNETS IN A FUSION EXPERIMENTAL REACTOR

A cryogenic helium pump system is the most effective method so as to cool the forced–flow cooled superconducting magnets in a fusion reactor by using supercritical helium (SHe). Japan Atomic Energy Research Institute has been developing such pump system with a high adiabatic pump efficiency and a large mass flow rate. Two kinds of the centrifugal pump have been developed, each has proved to have adiabatic efficiency of more than 80% at the design point: SHe flow rate of 300 to 400 g/s with the pump head of about 0.15 MPa at the pump inlet condition of around 4.5 K and 0.5 MPa. One was actually used for the magnet experiment and demonstrated advantages of the pump system.