Improved CVD Coatings for Carbide Based Nuclear Thermal Propulsion Fuel Elements

One of the great hurdles to further development and evaluation of nuclear thermal propulsion systems is the issue surrounding the release of radioactive material from the fuel during ground testing and its subsequent impact on test facility siting and operation. Therefore, the development of a crack resistant coating system on nuclear thermal propulsion fuel elements that is insensitive to hydrogen corrosion and erosion is considered enabling. Technology Assessment & Transfer Inc. (TA & T) proposes a systematic approach for CVD deposition and evaluation of a family of niobium carbide (NbC) coating systems for both uranium carbide-zirconium carbide solid solution [(U,Zr)C] and advanced triple carbide (uranium carbide-ziconium carbide-niobium carbide) solid fuel elements designed for use in space nuclear power and propulsion reactors. These refractory metal coating systems will be evaluated in high temperature hydrogen and helium in concert with a preliminary performance modeling effort.