Fabrication and Characterization of Uranium Thorium Zirconium Hydride Fuels

摘要

Hydride nuclear fuels (uranium-zirconium hydride) have been successfully utilized in the past in many research and test reactors as well as space programs. The added presence of hydrogen in the fuel provides neutron moderation within the fuel in addition to the traditional moderator. This allows displacement of moderator with fuel, effectively increasing power density. Hydride fuels also enjoy a higher thermal conductivity than oxide fuels and possess thermally-induced hydrogen up-scattering that accompanies Doppler feedback. Uranium-thorium-zirconium hydride fuel has been proposed as an optimized matrix for deep burn of plutonium and minor actinides. The proposed fuel could achieve TRU (transuranic elements) destruction fractions as high as twice realized with the MOX (mixed oxide) fuel. Unlike MOX fuel however, it is possible to realize infinite cycles of partitioning and transmutation with the hydride fuel without the risk of large positive reactivity coefficients as the cycles progress. It is therefore intended to fabricate and characterize two different compositions of uranium-thorium-zirconium hydride fuels in order to gain understanding of the properties and microstructure of the material system.