Abstract: A system and method for stabilizing fission products in a cermet for long term storage. The method includes forming a metal oxide precipitate, combining the metal oxide precipitate with an undissolved solid, and densifying the combined metal oxide precipitate and the undissolved solid to provide a cermet having a ceramic dispersed phase and a metallic matrix phase, wherein the metallic matrix phase includes metallic content from the undissolved solid. The undissolved solid can include fission product metals from the reprocessing of irradiated nuclear fuel. The cermet waste loading can be greater than approximately 30 percent, reducing waste volume by 50 percent or more when compared to baseline glassified articles.

Abstract: The present invention is directed to a method for making a wide variety of general-purpose cermets and for radioactive waste disposal from ceramic powders prepared from urea-dispersed solutions containing various metal values. The powders are formed into a compact and subjected to a rapid temperature increase in a reducing atmosphere. During this reduction, one or more of the more readily reducible oxides in the compact is reduced to a selected substoichiometric state at a temperature below the eutectic phase for that particular oxide or oxides and then raised to a temperature greater than the eutectic temperature to provide a liquid phase in the compact prior to the reduction of the liquid phase forming oxide to solid metal. This liquid phase forms at a temperature below the melting temperature of the metal and bonds together the remaining particulates in the cermet to form a solid polycrystalline cermet.