About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Ceramics and Ceramic-Based Composites for Nuclear Applications III
|
| Presentation Title |
Oxygen diffusion mediated by multi-dimensional defects in ThO2 |
| Author(s) |
Miaomiao Jin, Jilang Miao, Beihan Chen, Marat Khafizov, Yongfeng Zhang, David Hurley |
| On-Site Speaker (Planned) |
Miaomiao Jin |
| Abstract Scope |
Oxygen self-diffusion governs stoichiometry and defect evolution in oxide nuclear fuels. Understanding oxygen diffusion in ThO2 is essential for predicting its properties. In this talk, we will consider how multi-dimensional defects, including 1D (dislocation), 2D (grain boundary), and 3D (void) defects, contribute to the ionic conductivity. While they generally enhance oxygen transport via increased free volume, our atomistic simulations reveal a more complex picture depending on their structural characteristics. In particular, we find that grain boundaries, especially the Σ3(111) coherent twin boundary, exhibit unexpectedly high oxygen conductivity despite its compact structure. This behavior is attributed to a superionic state that exhibits highly efficient correlated oxygen motion, contrasting with conventional pipe diffusion observed at more open GBs. Our findings highlight that enhanced oxygen transport depends not solely on defect dimensionality or free volume but also on specific structural motifs, offering new insights for defect-engineered oxide materials. |
| Proceedings Inclusion? |
Planned: |