Design and technological solutions for the plasma facing components of WENDELSTEIN 7-X

The operation of W7-X stellarator for pulse length up to 30 min with 10 MW input power requires a full set of actively water-cooled plasma facing components. From the lower thermally loaded area of the wall protection system designed for an averaged load of 100 kW/m² to the higher loaded area of the divertor up to 10 MW/m², various design and technological solutions have been developed meeting the high load requirements and coping with the restricted available space and the particular 3D-shaped geometry of the plasma vessel. 80 ports are dedicated alone to the water-cooling of plasma facing components and a complex networking of kilometers of pipework will be installed in the plasma vessel to connect all components to the cooling system. An advanced technology was developed in collaboration with industry for the target elements of the high heat flux (HHF) divertor, the so-called “bi-layer” technology for the bonding of flat tiles made from CFC NB31 onto the CuCrZr cooling structure. The design, R&D and the adopted technological solutions of plasma facing components are presented. At present, except the HHF divertor, most of plasma facing components has been already manufactured.