Phase Relations in Crystalline Ceramic Nuclear Waste Forms: The System UO2+x‐CeO2‐ZrO2‐ThO2 at 1200°C in Air

Abstract

Steady‐state phase relations in the system UO2+x‐CeOz‐ZrO2‐ThO2 were determined for application to phase relations in high‐level crystalline ceramic nuclear waste forms. Samples were treated at 1200°C at an oxygen partial pressure of 21.3 kPa and a total pressure of 101.3 kPa. Phase assemblages were found to be comprised of cubic solid solutions of the fluorite‐structure type, solid solutions based on ZrO2, and orthorhombic solid solutions based on U3O8.