Coatings on a First Wall Plasma-Facing Surface: Analysis and High Heat Flux Testing on the Tsefey-M E-Beam Facility

Some aspects of the use of coatings for various functional purposes on the first wall plasma-facing surface of a thermonuclear reactor are considered. An important characteristic of coatings is adhesive and fatigue strength under cyclic impact of quasi-stationary heat loads, as well as resistance to high pulsed thermal loads. This paper describes thermal cyclic tests with surface thermal load of water-cooled mockups with various coatings on the heat-receiving surface. The B4C coating, made by atmospheric plasma spraying on a tungsten substrate, demonstrated excellent durability over 1400 thermal cycles at 4.7 MW/m2. CVD tungsten coating on a copper substrate demonstrated good results after 1000 thermal cycles at 3.3 MW/m2, but after a similar number of cycles at 5 MW/m2, cracks were detected on the surface. The stainless steel coating on a copper substrate demonstrated resistance to loads up to 11.9 MW/m2, as well as excellent durability over 1000 thermal cycles at 8.2 MW/m2.