Oxide Evolution on the SiC Layer of TRISO Particles during Extended Air Oxidation


Tristructural isotropic (TRISO) fuel particles have been primarily developed for high-temperature gas-cooled nuclear reactors and can be subjected to oxidizing environments for extended periods in an off-normal accident scenario. Surrogate TRISO fuel particles were oxidized in air at 1,000 or 1,100 °C for up to 120 h. The oxide scale morphology and thickness were studied via scanning electron microscopy, focused ion beam, and atomic force microscopy. TRISO particles oxidized at 1,100 °C exhibited a highly crystalline oxide scale, which led to significant cracking and irregularly shaped closed porosity, whereas those oxidized at 1,000 °C possessed a primarily amorphous oxide scale, which contained small, rounded internal pores and no larger defects. The observed phenomena deviated from the expected behavior based on models for oxide growth on flat-plate and fiber SiC. The oxidation kinetics of TRISO fuel particles in high-temperature air were investigated without mechanically deforming the surface and were analyzed with respect to oxide morphology.


Materials Science and Engineering


This study was financially supported by the Nuclear Energy University Program (award number DE-NE0008753) under the Office of Nuclear Energy of the US Department of Energy.

Keywords and Phrases

FIB; Microstructure; Oxidation; SiC; TRISO

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Article - Journal

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Publication Date

01 Jan 2022