Abstract
Tri structural isotropic (TRISO)-coated fuel particles are designed for use in high-temperature gas-cooled nuclear reactors, featuring a structural SiC layer that may be exposed to oxygen-rich environments over 1000 °C. Surrogate TRISO particles were tested in 0.2–20 kPa O2 atmospheres to observe the differences in oxidation behavior. Oxide growth mechanisms remained consistent from 1200–1600 °C for each PO2, with activation energies of 228 ± 7 kJ/mol for 20 kPa O2 and 188 ± 8 kJ/mol for 0.2 kPa O2. At 1600 °C, kinetic analysis revealed a change in oxide growth mechanisms between 0.2 and 6 kPa O2. In 0.2 kPa O2, oxidation produced raised oxide nodules on pockets with nanocrystalline SiC. Oxidation mechanisms were determined using Atom probe tomography. Active SiC oxidation occurred in C-rich grain boundaries with low PO2, leading to SiO2 buildup in porous nodules. This phenomenon was not observed at any temperature in 20 kPa O2 environments.
Recommended Citation
V. Jalan et al., "Influence of Temperature, Oxygen Partial Pressure, and Microstructure on the High-temperature Oxidation Behavior of the SiC Layer of TRISO Particles," Journal of the European Ceramic Society, vol. 45, no. 2, article no. 116913, Elsevier, Feb 2025.
The definitive version is available at https://doi.org/10.1016/j.jeurceramsoc.2024.116913
Department(s)
Materials Science and Engineering
Keywords and Phrases
Atom probe tomography; Electron microscopy; Oxidation; Silicon carbide; TRISO particle
International Standard Serial Number (ISSN)
1873-619X; 0955-2219
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2025 Elsevier, All rights reserved.
Publication Date
01 Feb 2025
Comments
Oak Ridge National Laboratory, Grant DE-NE0008753