Beryllium and Tungsten Brush Armor for Plasma Facing Components

196 Beryllium and Tungsten Brush Armor for Plasma Facing Components--Plasma Processes, Inc., 4914 D Moores Mill Road, Huntsville, AL 35811-1558; (205) 851-7653 Dr. Timothy McKechnie, Principal Investigator Ms. Cheri McKechnie, Business Official DOE Grant No. DE-FG02-97ER82458 Amount: $75,000 Robust attachment of plasma-facing component armor is critical to the design and operation of magnetic fusion energy devices. Recent high heat flux testing has shown that when large bonded tiles develop high thermal stresses, the bonds break. Finite element modeling has shown that the thermal stresses between the low expansion armor and the high expansion copper heat sinks are lowered significantly as tile size of the armor is decreased. The theoretical solution is to fabricate a brush structure for the armor. Therefore, the objective of this Phase I project is to develop and fabricate small-scale plasma-facing component armor of tungsten and beryllium to demonstrate brush armor fabrication and properties. The individual brush filaments or bristles can be made 3 millimeters and smaller and packed together such that the heat sink is protected from the fusion plasma better than machining complex tile breaks. Thermal stresses will be minimized by the brush structure as the individual brush members can expand and contract with the heat sink. Using conical tips on the bonded end of the brush members, three-dimensional bond joints will be produced. Increased armor life at high heat flux will then be realized with the brush structure. During Phase II, the fabrication techniques developed during Phase I will be optimized. Finite element modeling of the brush structure will be performed, on tip design and stress concentration at the brush joint. These optimized techniques will then be used to fabricate a medium-scale mockup for high heat flux testing. Commercial Applications and Other Benefits as described by the awardee: This research may have commercial applications in the following areas: fusion reactor plasma-facing components, furnace heat sinks, rocket and jet engines, radiators, satellite thermal management, high-voltage electrical contacts, heat sinks, beam targets, and welding electrodes._