Qualification of the TIC conductor for the in-vessel coils in ASDEX upgrade

ASDEX Upgrade will be evolved by installing a new upper divertor with two in-vessel coils allowing the investigation of alternative magnetic configurations. The in-vessel coils will be bended inside the torus. The co-axial conductor consists of a Tefzel insulated water cooled copper core embedded into a stainless steel protection shield. To test the conductor concept and to qualify the electrical and thermal properties of the Tefzel insulated conductor (TIC), prototype conductors of 3 and 8 m length were used. These conductors undergo electrical and thermal tests accompanied by FEM calculations. The electrical tests include high voltage and partial discharge tests. For thermo-mechanical tests the prototype conductors were fed with up to 13 kA for 5 s. During the test the copper conductor was heated up by 60 K. The Tefzel cladding and the protection tube are warmed up with a delay given by the thermal heat conduction and capacity. The thermo-mechanical behaviour of the TIC during the heating and cooling phase could be confirmed by the FEM-models. As part of the qualification, the conductor was thermally overloaded by a factor of 3, without degradation.

spara010^>The paper presents the electrical and thermal tests as well as the results of the related FEM calculations.