Redistribution of radionuclides in irradiated AGR-1 UCO TRISO fuel after 1800 °C safety testing

Gerczak, Tyler J.; Seibert, Rachel; Hunn, John D.; Baldwin, Charles A.; Montgomery, Fred C.; Morris, Robert Noel

doi:10.1016/j.jnucmat.2020.152453

Cited by 5 publications

(2 citation statements)

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“…Regardless, the post‐oxidation microstructure analysis shows that passive oxidation to form amorphous SiO 2 occurs over the bulk of the particle surface and suggests that local active oxidation followed by redeposition of porous, crystalline SiO 2 occurred in these experiments. Similarly, localized SiC reactions were also observed during high‐temperature safety testing of SiC in irradiated TRISO fuel 48 . Here, only local regions of the outer SiC surface appear to decompose.…”

Section: Discussionmentioning

confidence: 54%

“…Similarly, localized SiC reactions were also observed during high-temperature safety testing of SiC in irradiated TRISO fuel. 48 Here, only local regions of the outer SiC surface appear to decompose. This, coupled with the local SiC microstructural variations, would lend support to a potential microstructurally dependent response of the SiC layer to deleterious conditions as observed in the work.…”

Section: The Nature Of Crystalline Sio 2 Nodulesmentioning

confidence: 95%

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High‐temperature oxidation behavior of the SiC layer of TRISO particles in low‐pressure oxygen

et al. 2023

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Surrogate tristructural-isotropic (TRISO)-coated fuel particles were oxidized in 0.2 kPa O 2 at 1200-1600 • C to examine the behavior of the SiC layer and understand the mechanisms. The thickness and microstructure of the resultant SiO 2 layers were analyzed using scanning electron microscopy, focused ion beam, and transmission electron microscopy. The majority of the surface comprised smooth, amorphous SiO 2 with a constant thickness indicative of passive oxidation. The apparent activation energy for oxide growth was 188 ± 8 kJ/mol and consistent across all temperatures in 0.2 kPa O 2 . The relationship between activation energy and oxidation mechanism is discussed. Raised nodules of porous, crystalline SiO 2 were dispersed across the surface, suggesting that active oxidation and redeposition occurred in those locations. These nodules were correlated with clusters of nanocrystalline SiC grains, which may facilitate active oxidation.These findings suggest that microstructural inhomogeneities such as irregular grain size influence the oxidation response of the SiC layer of TRISO particles and may influence their accident tolerance.

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Section: Discussionmentioning

confidence: 54%

Section: The Nature Of Crystalline Sio 2 Nodulesmentioning

confidence: 95%