| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Advanced Characterization of Materials for Nuclear, Radiation, and Extreme Environments
|
| Presentation Title |
Material Degradation Pathways of UO2 under Oxygen, Humidity, and Temperature Probed by XAFS |
| Author(s) |
Juejing Liu, Aiping Chen, Joanne Stubbs, Peter Eng, Hongwu Xu, Steven Conradson, Xiaofeng Guo |
| On-Site Speaker (Planned) |
Juejing Liu |
| Abstract Scope |
UO2 is the major component material for nuclear fuel rods for LWR or PWR. Understanding uranium oxide – water interfacial structures and chemical reactions are critical for addressing a wide range of high-profile issues in the nuclear fuel cycle, related to reactor fuel safety and geological disposal. Herein, we performed glazing incident X-ray absorption fine structure to probe changes of lattice structures of UO2 thin films under various humidity, oxygen level, and temperature conditions. Our preliminary results show that the UO2 lattice is distorted even in low humidity. Increasing humidity introduces two or three extra O atoms in the interstitial site (2.4~2.8 Å from U), suggesting the gradual formation of non-stoichiometric UO2+x or U4O9. This study provided an insight into the potential impacts of external conditions on UO2 from the atomic scale, which helped unveil all possible material degradation pathways. |