Advancement on the procurement of Power Supply systems for JT-60SA

JT-60SA will be provided with a set of power supply systems procured by Europe and Japan under the framework of Broader Approach Agreement. The toroidal circuit is supplied by an ac/dc thyristors converter rated for 25.7 kA in steady state, and the toroidal superconducting coils are protected by three Quench Protection Circuits (QPC) assuring fast dissipation of the stored magnetic energy of about 1 GJ in case of fault. The poloidal circuits are supplied by ten ac/dc thyristor converters, almost all rated for ±20 kA and ±1 kV; ten QPC rated for the same nominal current and ±3.8 kV assure the protection of the poloidal superconducting coils. The high voltage required for the plasma breakdown is generated in the poloidal circuits by four Booster ac/dc converters and by six Switching Network Units (SNU). The Booster converters are rated +4/−14.5 kA and ±5 kV for short time, thus are inserted in the circuits only when needed and then bypassed. The SNU are operated in order to insert in the circuits settable resistors, producing up to 5 kV at the nominal current of 20 kA, and then to by-pass them after plasma initiation phase. Two in-vessel coils for fast control of plasma position are supplied by two independent ac/dc thyristor converters, rated ±5 kA and ±1 kV, and the in-vessel coils for Resistive Wall Mode control are supplied by 18 fast inverters rated for 300 A and 240 V. After a preliminary definition of the reference schemes and main requirements of the components, the procurement of the Power Supply systems has been started by means of contracts awarded to industrial suppliers including detailed design, manufacturing and test. Besides highlighting the main characteristics of Power Supply systems of JT-60SA as resulting after the detailed design, the paper describes the present status of their procurement: the QPC units have been already installed in Japan for the final acceptance test; the manufacture and factory tests of some SNU have been successfully completed; the detailed design of ac/dc converters for toroidal and poloidal circuits has been finalized, and the first units have been manufactured and are ready for factory testing.