DescriptionFor decades cerium dioxide (CeO2 or ceria) has been widely studied for its applications in green technologies. Ceria is commonly used as a simulant material for PuO2 in mixed oxide (MOX) fuels as both species share the fluorite structure and similar thermal conductivities in addition to Ce and Pu both occupying the 3+ and 4+ oxidation states. The advantage of ceria as a surrogate is that plutonia is toxic and radioactive which CeO2 is not. Ceria also requires less computational resources when utilising modelling techniques such as density functional theory as spin-orbit coupling and non-collinear magnetic do not need to be employed. The high temperatures nuclear fuels experience during their operation result in the formation intrinsic Frenkel and Schottky defects. These defects impact the redox cycle, oxygen storage capacity and thermal properties, for example the thermal conductivity of the defect models of ThO2reduced by 90% compared to the pristine model. We used DFT to study the structural dynamics and thermal properties of the Frenkel and Schottky defect models of ceria finding the defects broaden the main branches in the phonon dispersions, have characteristic features in the IR spectrums and significantly reduce the thermal conductivity compared to the pristine structure. This methodology can be applied to any nuclear materials to model thermal properties.
|7 Sep 2022
|CCP5 Annual General Meeting 2022, 42nd edition
|Huddersfield, United Kingdom
|Degree of Recognition