Lessons learned from the design and fabrication of the baffles and heat shields of Wendelstein 7-X

The baffles and heat shields of the wall protection of the Wendelstein 7-X stellarator are actively water cooled components based on the same technology. Fine grain graphite tiles are clamped onto a CuCrZr heat sink, which is vacuum brazed to a stainless steel tube. The baffles are part of the divertor and improve the divertor pumping efficiency. The heat shields protect the plasma vessel wall, water piping, cables and the integrated diagnostics. The 170 baffles with 25 variants and 162 heat shield modules with 85 variants comprise a total surface of 33 m2 and 51 m2, respectively. Design guidelines enabled as much as possible the standardization of the fabrication to allow for a more efficient work organization. Individual jigs have been manufactured for each variant in order to weld, bend and mill the different parts of the baffles and heat shields to the required 3D accuracy. At the end of the manufacturing process, each component has been checked and documented according to a detailed quality plan.