F. Werner

Completion of Assembly and Start of Technical Operation of ASDEX Upgrade

The last important steps of the tokamak machine assembly are described. A survey of precision and tolerances is given achieved for the vacuum vessel, the toroidal field (TF) magnet and the poloidal field (PF) coils. The first commissioning tests of vacuum vessel, TF magnet and PF coils are described together with certain features of the control and technical supervisory system. Remarks on improvements of the electric power supply system and the fast plasma control system follow. Finally the programme of the next future is briefly outlined.

THE TECHNICAL CONCEPT OF THE ASDEX UG POLOIDAL FIELD COILS

The ASDEX UG tokamak poloidal field coil system will comprise three ohmic heating coils and three vertical field coils. The ohmic heating coils consist of a highly excited coil in the central bore of the toroidal field magnet and coils outside the toroidal magnet arranged in pairs symmetric to the torus mid-plane. This coil arrangement is expected to generate a magnetic flux swing of about 9.5 Vs for a total discharge time of the plasma of 10s. The vertical field coils can be arranged a) all outside the toroidal magnet system, and b) partially between the toroidal magnet system and the vacuum vessel, likewise in pairs symmetric to the torus midplane.

The ZEPHYR poloidal field coils

The magnetic field of the poloidal coils creates plasma equilibrium conditions, plasma breakdown and heating and may be formed by two separate coil systems (OH; V). All coils without the central OH coil (OH 1) are normally stressed; less than 100 MPa. The extremely stressed OH central coil (350 MPa)must be specially designed for keeping stress and temperature rise low. The start temperature of OH 1 has to be less than 80 K for keeping the temperature rise i=9.1 \frac{KA}{cm^{2}} ; t pulse = 4.5 s. All coils are designed for direct cooling. Cool medium can be Li N2 or supercritical He at high pressure.

Technical Concept for the Multipole Coils of ASDEX

The axisymmetric divertor field of the ASDEX Tokamak is induced by two triplets of multipole coils situated within the vacuum vessel above and below the plasma region. One coil of a triplet is wound with eight turns and two coils with four turns. The installation of the multipole coils requires, that the coils must be divided into two halves connected by demountable joints. The windings isolated with structural reinforced resin and placed in vacuum-tight stainless steel bellows are fixed to the vacuum vessel by 16 holdings.