Structural and phase evolution in U\(_3\)Si\(_2\) during steam corrosion

U\(_3\)Si\(_2\) nuclear fuel is corroded in deuterated steam with in situ neutron diffraction. Density functional theory is coupled with rigorous thermodynamic description of the hydride including gas/solid entropy contributions. H absorbs in the 2\(b\) interstitial site of U\(_3\)Si\(_2\)H\(_x\) an...

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Bibliographic Details
Published in:arXiv.org 2022-02
Main Authors: Liu, Jiatu, Burr, Patrick A, White, Joshua T, Peterson, Vanessa K, Dayal, Pranesh, Baldwin, Christopher, Wakeham, Deborah, Gregg, Daniel J, Sooby, Elizabeth S, Obbard, Edward G
Format: Article
Language:English
Subjects:
Corrosion
Density functional theory
Deuteration
Germanium
Grain boundaries
Neutron diffraction
Neutrons
Nuclear fuels
Silicon
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Summary:U\(_3\)Si\(_2\) nuclear fuel is corroded in deuterated steam with in situ neutron diffraction. Density functional theory is coupled with rigorous thermodynamic description of the hydride including gas/solid entropy contributions. H absorbs in the 2\(b\) interstitial site of U\(_3\)Si\(_2\)H\(_x\) and moves to 8\(j\) for \(x\ge 0.5\). Hydriding forces lattice expansion and change in \(a/c\) ratio linked to site preference. Rietveld refinement tracks the corrosion reactions at 350-500 \deg C and preference for the 8j site. Above 375 \deg C, formation of UO\(_2\), U\(_3\)Si\(_5\) and USi\(_3\) take place in the grain boundaries and bulk. Hydriding occurs in bulk and precedes other reactions.
ISSN:2331-8422