Performance and statistical quality assessment of CFC tile bonding on the pre-series elements of the Wendelstein 7-X divertor

Extensive high heat flux (HHF) testing of pre-series IV targets was performed to establish the industrial process for the ongoing production of the actively water-cooled target elements which will be needed for the installation of the Wendelstein 7-X (W7-X) divertor. Finally, 890 components covered with about 18,000 CFC tiles will be installed. aminations of the elements with 10 MW/m2 cycling up to 10,000 pulses, 16 MW/m2 cycling and screening tests up to 32 MW/m2, confirm the robustness of the design and in particular of the applied CFC bonding technology. The results of the IR examination of the initial tests have been assessed statistically. The paper presents a detailed statistical analysis based on the Six-Sigma method of the surface temperature increase of the CFC tiles tested for 100 cycles at 10 MW/m2. Assuming that the series elements will behave in a similar fashion to the pre-series elements this statistical assessment can also be performed for the series elements.