About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
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Radiation Effects in Metals and Ceramics
|
Presentation Title |
H-30: Equilibrium and Irradiation-induced Point-defect Disorder in ThO2 and U-doped ThO2: Modeling and Ion Irradiation Experiments |
Author(s) |
Maniesha Singh, Tiankai Yao, Lingfeng He, Anter El-Azab |
On-Site Speaker (Planned) |
Anter El-Azab |
Abstract Scope |
A thermodynamic defect disorder model was used to investigate the off-stoichiometry behavior in ThO2 and U-doped ThO2. The model shows that while ThO2 remains mostly hypo-stoichiometric at relevant temperature and oxygen partial pressure conditions, U doping expands the thermodynamics window over which ThO2 becomes hyper-stoichiometric, thus illustrating the impact of 5f electrons introduced by the U doping on defect disorder. For example, U0.52Th0.48O2+x can sustain disorder up to an oxygen off-stoichiometry content of x = 0.4 at high temperatures and high oxygen pressure whereas U0.2Th0.8O2+x can only exist up to an oxygen off-stoichiometry content of x = 0.05. The extent of hyper-stoichiometry in the oxide increases with decreasing temperature and increasing oxygen partial pressure values. Presented also are the results of a cluster dynamics model of vacancy and interstitial cluster formation under irradiation in conjunction with microstructure and chemical analysis of ion-irradiated ThO2 at different temperatures in TEM. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |