The development of beryllium first wall components for future magnetic confinement fusion experiments such as the International Thermonuclear Experimental Reactor (ITER) is a topic of great importance as the ITER construction phase is about to begin. The beryllium components must be able to survive the harsh plasma environment for extended periods of time during operation. Furthermore, cost and detrimental health effects must be kept to a minimum during the fabrication and operation processes. The work described here details the requirements for ITER first wall components and describes experiments to produce beryllium high heat flux components by plasma spray deposition. Experimental parameters and characterization results from the components are presented. Results of initial high heat flux testing under electron beam irradiation show performance exceeding that required for ITER first wall components.

Transferred-arc cleaning is being investigated as a solvent-free cleaning method for various metallic substrates. With the recent increase in attention given the hazards involved in the storage, use and disposal of organic solvents, cleaning methods which promise comparable cleaning effectiveness with reduced hazards are being sought. Transferred-arc cleaning of tungsten substrates has been studied to identify the effect of processing conditions on cleaning and roughening characteristics. A Box-Behnken response surface designed experiment varying the chamber pressure, substrate standoff distance and plasma torch arc current while observing the transferred-arc voltage, current, surface cleanliness and surface roughness was performed. The results of the analysis show the effect of the various independent variables on the measured responses. Particular difficulties in roughening tungsten are due to its exceptionally high arc voltage for metal arc attachment. The results presented here provide an enhanced understanding of the arcing properties of various cathode materials. Such information is useful in obtaining the desired cleaning and/or roughening of the substrate.