Dysprosia Doped Uranium Dioxide Fuel and the Lambda Transition

Abstract

Thermodynamic properties of solid and liquid UO₂, at temperatures above 2500 K, are rare and difficult to interpret. Low Void Reactivity Fuel (LVRF) employs Dysprosia in the originally natural Uranium fuel, but sufficient knowledge of solubility at all temperatures is still deficient. This paper describes research into the physical chemistry of UO₂-Dy₂O₃ mixtures, and includes an assessment of Dy₂O₃ effects on UO₂ at high temperatures. Specifically, research was conducted on the Lambda transition occurring at approximately 2670 K. The crystal structure determined by neutron diffraction and its effect on thermodynamic properties is discussed.