Realisation of the cooling system of the non-planar coils for W7-X

During the design phase of the Wendelstein 7-X coils it was found that the foreseen full coating by copper plates can no longer be applied. Other methods therefore had been investigated for realisation of the copper coating (IEEE Trans. Appl. Superconductivity 12, 1261). Taking into account all existing boundary conditions it turned out that thermal spraying is the best solution for this task. In addition to the coating, the coils should be equipped with sheets of high conductivity copper in thermally high loaded regions. We report in this paper about our investigations to characterise the thermal sprayed copper coating with respect to its physical properties and the necessary tests and procedures for the realisation of the cooling system.