|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Thermal Property Characterization, Modeling, and Theory in Extreme Environments
||Phonon Transport in ThO2 from Neutron Scattering and First-principles Computation
||Michael E. Manley, Matthew S. Bryan, Chris A. Marianetti, Lyuwen Fu, Krzystof Gofryk
|On-Site Speaker (Planned)
||Michael E. Manley
We are investigating the microscopic origin of thermal transport in advanced oxide nuclear fuels, including thorium dioxide, using inelastic neutron scattering and first-principles calculations. Neutron scattering measurements performed on large single crystals provide a direct measure of the phonon group velocities and lifetimes controlling lattice thermal transport. These quantities enable us to deduce mode specific contributions to thermal transport. Since the phonon scattering processes responsible for lifetime broadening involve anharmonic interactions between multiple branches, a full accounting requires accurate calculations. Density functional theory (DFT) captures the phonon dispersion curves of ThO2 and allows calculations of the anharmonic terms from which phonon lifetimes are derived. The results of these calculations are benchmarked against the inelastic neutron scattering phonon dispersion and linewidth/lifetime measurements as well as thermal transport measurements.