About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
Phonon and Thermodynamic Properties of Defected-ThO<sub>2</sub> and (U,Th)O<sub>2</sub> |
Author(s) |
Maniesha Singh, Tomohisa Kumagai, Anter El-Azab |
On-Site Speaker (Planned) |
Maniesha Singh |
Abstract Scope |
The effect of point defects with varying charge states on phonon and thermodynamics properties of nuclear oxides, ThO<sub>2</sub> and (U,Th)O<sub>2</sub>, is investigated through the density functional theory (DFT) simulations. Firstly, two methods, zero pressure and constant volume, are used to perform DFT simulations where the results show that the vibrational entropy and formation energy of point defects in ThO<sub>2</sub> is under- and over-estimated, respectively. Secondly, the change in volume of supercell due to point defects is studied. When the charge state of an anionic vacancy or a cationic interstitial defect is increased from neutral to its maximum, a supercell contraction is observed. On the contrary, in the case of an anionic interstitial or a cationic vacancy defect, a supercell expansion is found. Lastly, the effect of defects on the phonon dispersions and density of states is examined. |
Proceedings Inclusion? |
Planned: |
Keywords |
Computational Materials Science & Engineering, High-Temperature Materials, Nuclear Materials |