|About this Abstract
||MS&T23: Materials Science & Technology
||Ceramics for New Generation Nuclear Energy System Application
||Modeling the Effect of Point Defect Scattering on the Thermal Conductivity of ThO2
||Erika Nosal, Saqeeb Adnan, Miaomiao Jin, Linu Malakkal, Marat Khafizov
|On-Site Speaker (Planned)
The thermal conductivity of nuclear fuels governs the temperature distribution within fuel rods, which determines the fuel’s ability to maintain its mechanical integrity and retain fission products. This work implements first-principles based calculations to investigate the impact of point defects on the thermal conductivity of ThO2 used as a model for fluorite oxides. We analyze the impact of vacancies and interstitials within the Boltzmann transport formalism. Phonon defect scattering is calculated using the Born approximation, which accounts for changes to the interatomic forces around the defect site as a first-order perturbation. The interatomic interactions needed to evaluate 3-phonon and phonon-defect interactions are derived from density-functional calculations. Results indicate that thorium sublattice defects contribute to the largest reduction in conductivity, compared to their oxygen counterparts. We compare the Born approximation results to phonon scattering predicted by the Tamura model, nonequilibrium molecular dynamics simulations, and experimental measurements of ion irradiated ThO2.