In-Vessel Components

The major in-vessel components are the divertor cassettes (and cryopanels for particle pumping), the inboard first wall, the stabilizing baffle plate and outboard first wall, the fast plasma position control coils, the sector coils for resistive wall mode (RWM) control, the magnetic diagnostic coils, both inside and outside the vessel, and error correction coils mounted on the external vessel surface.

Initially only a lower divertor will be installed, optimised to allow ITER-shape and high-triangularity plasmas. A fully equipped upper divertor is planned at the start of the extended research phase. A mono-block type CFC divertor armour is planned for the outboard side to withstand a heat load of ~15 MW/m². This will be replaced with a flat tile type divertor armour during the initial research phases due to the smaller expected heat load once operation is better understood.

Full remote handling compatibility will be built up during the initial phases of operation, ready for full remote divertor tile replacement before the extended research phase.

Cryopanels will be installed behind the divertor to improve pumping capability. A water-cooled chevron is installed in front of the pumping hole to reduce heat load on the cryopanels.

Two in-vessel coils will be used for fast plasma position control. Independent power supplies will be connected to each coil block to control vertical and horizontal field at the same time.

The primary function of the stabilizing baffle plates is to enhance the ideal beta limit and to improve plasma positional stability. They have been designed as a double-wall structure and are covered with a bolted carbon-armoured first wall.

The sector coils for the RWM control will be installed around the openings of the stabilizing baffle plate to minimize the control response time. Since each sector coil has its own current leads, the magnetic field mode of m/n = 3/1 or 3/2 can be controlled depending on the configuration of the power supply connections.