CONCEPTUAL DESIGN STUDY OF A STEADY STATE TOKAMAK DEVICE

A steady state tokamak (: JT-60 Super Upgrade) is investigated with maximum utilization of existing JT-60 facility. The goal of the research program is the integrated physics and technology evaluation of high-efficiency steady state operation with high input power. The device uses superconducting TF and PF magnet systems, and long pulse high-heat load divertor plates. The tokamak system is located within an evacuated cryostat & biological shield. A plasma current of 10MA is chosen to investigate extended confinement regimes. Long pulse operation with 100's-1000's of sec will be investigated using non-inductive current drive, mainly by 0.5MeV negative ion beam injection of ~60MW; and with impurity and particle control in reactor-like tokamak environment of 15MW/m 2 divertor heat flux. Because of the long pulse operation, the vessel activation requires in-vessel remote maintenance equipment for short period (~1 month) of in-vessel work even for D-D discharge operation. Low activation materials, such as titanium alloys are chosen as the best candidate material for the water-tank type vacuum vessel, which also serves as the nuclear shield for the superconducting coils. These materials allow human access for repair work after ~1 year of shut-down in case of major device failure.