About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Ceramics and Ceramic-Based Composites for Nuclear Applications III
|
| Presentation Title |
Atomistic mechanism of faulted loop formation in fluorite oxide under irradiation |
| Author(s) |
Lin-Chieh Yu, Shuxiang Zhou, Linu Malakkal, Marat Khafizov, David Hurley, Yongfeng Zhang |
| On-Site Speaker (Planned) |
Lin-Chieh Yu |
| Abstract Scope |
Understanding defect evolution is critical for realizing the potential of fluorite oxides in nuclear applications. In UO2 and ThO2, interstitials can aggregate into dislocation loops, degrading thermal conductivity and promoting swelling. However, the loop formation mechanism remains unclear due to limitations in direct observation and modeling at atomic scales. Notably, the low mobility of cation interstitials predicted by density functional theory (DFT) contradicts experimental observations. Using ThO2 as a model system, we employed molecular dynamics (MD) to identify mobile interstitial clusters evolving from isolated thorium and oxygen interstitials. Their thermal stability and mobility were further confirmed via high-accuracy DFT. The results suggest three key steps to faulted loop formation: i) oxygen-assisted diffusion of thorium interstitials, ii) growth of 1D-migrating thorium clusters, and iii) their transformation into faulted loops, which unfault into full loops. This mechanism, distinct from that in metals, offers insights into defect evolution. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Modeling and Simulation, Nuclear Materials, Ceramics |