Molecular dynamics simulation of energetic uranium recoil damage in zircon |
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Authors: | R. Devanathan L. R. Corrales W. J. Weber A. Chartier C. Meis |
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Affiliation: | 1. Fundamental Science Directorate, Pacific Northwest National Laboratory , Richland, WA, 99352, USA ram.devanathan@pnl.gov;3. Fundamental Science Directorate, Pacific Northwest National Laboratory , Richland, WA, 99352, USA;4. CEA Centre d'Etudes de Saclay , 91191, Gif-Sur-Yvette, France |
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Abstract: | Defect production and amorphisation due to energetic uranium recoils in zircon (ZrSiO4), which is a promising ceramic nuclear waste form, is studied using molecular dynamics (MD) simulations with a partial charge model. An algorithm that distinguishes between undamaged crystal, crystalline defects and amorphous regions is used to develop a fundamental understanding of the primary damage state. The amorphous cascade core is separated from the surrounding crystal by a defect-rich region. Small, chemically inhomogeneous amorphous clusters are also produced around the core. The amorphous regions consist of under-coordinated Zr and polymerised Si leading to amorphisation and phase separation on a nanometer scale into Zr- and Si-rich regions. This separation could play an important role in the experimentally observed formation of nanoscale ZrO2 in ZrSiO4 irradiated at elevated temperatures. |
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Keywords: | Molecular dynamics Amorphisation Nuclear waste form Uranium recoil |
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