Plasma-sprayed beryllium on macro-roughened substrates for fusion reactor high heat flux applications

The development of beryllium first wall (FW) plasma facing components for future magnetic confinement fusion experiments, such as the International Thermonuclear Experimental Reactor (ITER), is a topic of great importance as research into long-term energy sources increases in urgency. The FW components must be able to survive the harsh plasma environment for extended periods of time. One proposed method for initial fabrication and repair of FW components is plasma spraying. Previous plasma-sprayed beryllium mock-up FW components had coating separation from the substrate at the edges. The present work describes experiments to produce beryllium mock-up FW components by plasma spray deposition on macro-roughened substrates. Experimental parameters, high heat flux testing and characterization results from the components are presented. No separation of the coating from the substrate was observed. Results of high heat flux testing under electron beam irradiation show performance exceeding that required for ITER FW components. Differences in macro-roughening features result in changes in the threshold absorbed heat flux before damage to the coatings occurs.