The Effect of Interfacial Material on Tailored Ceramic Nuclear Waste Form Dissolution

Abstract

The long radioactive lifetime of the fission products in nuclear wastes requires that the material be isolated from the biosphere for periods of 10³ to 10⁵ years. One method of accomplishing this is to consolidate the waste into a chemically stable solid form contained within a multiple barrier canister which can be transported to a geologically stable repository for long-term storage. A number of candidate solid waste forms are being assessed to determine their suitability for incorporating various nuclear waste compositions. These include the current reference form (borosilicate glass), ceramics, high silica glasses, and cementitious forms. In this laboratory, research is currently being conducted on chemically immobilizing synthetic nuclear waste in high alumina content tailored ceramics, made by high temperature and pressure consolidation of the waste material with selected additives to produce a fully dense, fine grain ceramic.¹ The specific crystalline phase assemblages produced by tailoring the waste sludge provides chemical host sites for the individual radionuclides in ceramic phases which closely approximate natural mineral assemblages that have proven stability over geologic time scales.