High heat flux tests of the WENDELSTEIN 7-X pre-series target elements: Experimental evaluation of the thermo-mechanical behaviour

The high heat flux (HHF) testing of WENDELSTEIN 7-X pre-series target elements is an indispensable step in the qualification of the manufacturing process. A set of 20 full scale pre-series elements was manufactured by PLANSEE SE to validate the materials and manufacturing technologies prior to the start of the series production. F tests were performed in the ion beam test facility GLADIS. All actively water-cooled elements were tested for about 100 cycles at 10 MW/m2 (10–15 s pulse duration). Several elements were loaded with even higher cycle numbers (up to 1000) and heat loads up to 24 MW/m2. Hot spots were, observed at the edges of several tiles during the HHF tests indicating local bonding problems of the CFC. ermo-mechanical behaviour under HHF loading has been evaluated and compared to the FEM predictions. The measured temperatures and strains confirm the chosen FEM approach. This allows a component optimisation to achieve a successful series production of the W7-X divertor target elements.