HIGHLY EFFICIENT HEAT-DISSIPATING FUNCTIONALLY GRADIENT PLASMA FACING MATERIALS

CURRENTLY, NO SINGLE MATERIAL SATISFIES ALL THE DESIGN REQUIREMENTS FOR PLASMA FACING COMPONENTS IN MAGNETIC FUSION DEVICES. THEREFORE COMPLEX DESIGNS HAVE BEEN PROPOSED AND TESTED, BUT OPERATION OF THE DEVICES IS STILL LIMITED. INNOVATIVE TECHNIQUES ARE PLANNED IN THIS PROJECT TO FABRICATE FUNCTIONALLY GRADIENT HIGH-Z (ATOMIC NUMBER) TO LOW-Z PLASMA FACING MATERIALS INCORPORATING ACTIVE COOLING, ALLOWING FOR THE SELECTION OF OPTIMUM MATERIALS IN THE OPTIMUM LOCATIONS. COMPONENTS WILL BE FABRICATED UTILIZING VACUUM PLASMA SPRAY TO FORM A GRADIENT STRUCTURE OF COPPER TO TUNGSTEN TO LOW-Z BORON AND BORON NITRIDE IN CONTINUOUS GRADIENTS. THE GRADIENTS WILL MINIMIZE DIFFERENCES IN THERMAL EXPANSION AND LATTICE MISMATCH. THE BORON SURFACE WILL MINIMIZE HEAVY METAL PARTICLE IMPURITIES AND CAN BE NITRIDED TO INCREASE STABILITY. PLASMA FACING COMPONENTS WILL BE FORMED THAT FEATURE HIGHLY EFFICIENT HEAT DISSIPATION THROUGH INTEGRAL COOLING CHANNELS. THE COMPONENTS WILL BE DESIGNED SO THAT THERE ARE NO BONDLINE INTERRUPTIONS BETWEEN THE PLASMA EXPOSED SURFACE AND THE COOLING MEDIA. THE PHASE I EFFORTS SHOULD DEMONSTRATE THE ABILITY TO FABRICATE THE FUNCTIONAL GRADIENTS OF THE MATERIALS OF INTEREST; INITIAL PARAMETERS WILL BE INVESTIGATED, AND SAMPLE MATERIALS WILL BE FABRICATED FOR PHASE II CHARACTERIZATION.