Performance test results of cryogenic pump system for Demonstration Poloidal Coil

The system, composed of a circulation pump and a cold compressor, is designed to produce supercritical helium with a mass flow rate of 350 g/sec at 10 bar below 4 K in normal operation. The circulation pump uses a reciprocating-pump design with double-acting bellows. The cold compressor uses a centrifugal compressor design with dynamic gas bearings. In performance tests using real cryogenic pumps for the Japan Atomic Energy Research Institute Demonstration Poloidal Coil program, it was found that the measured maximum flow rate is around 680 g/sec at a pressure head of 1.1 bar with adiabatic compression efficiency of more than 60%.