System design of the demonstration poloidal coils and the test facility

A program of large pulse coils for investigation of superconducting pulse-coil technology required for the Fusion Experimental Reactor (FER) has been conducted. In this program, the pulse coils are separated into three coils (DPC-U1, U2 and EX) with forced-flow superconductor cooled by supercritical helium at 350 g/s under conditions of 10 bar and below 4 K. For this purpose, a new cryogenic pump system, which is composed of a circulation pump and a cold compressor, is developed and installed in the existing Superconducting Engineering Test Facility in order to produce and circulate supercritical helium at 500 g/s in the maximum. A newly developed vapor-cooled current lead with a cable-in conduit shape has been selected for the current leads and its rated current and insulation testing voltage are specified to be 30 kA and AC 16 kV, respectively. In addition, for pulse operation of the coil system, the JT-60 power supply system, which has a maximum capacity of ± 92 kA and ± 2.5 kV, is connected to charge the coils. The latest design and development status of this facility are described in this paper.