Microstructural evolution of gas bubbles and thermal conductivity in UO.sub.2-BeO bicrystal

UO.sub.2-BeO is an important composite nuclear fuel with high thermal conductivity. The impact of grain boundaries between UO.sub.2-UO.sub.2 and phase boundaries between UO2-BeO on the bubble evolution and the thermal conductivity in nuclear fuels is significant. In this study, we utilize a 3D phase...

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Bibliographic Details
Published in:Journal of materials science 2023-08, Vol.58 (29), p.11944
Main Authors: Liang, Chuanxin, Su, Yunting, Hao, Mengyuan, Dong, Tianjiao, Gong, Hengfeng, Liu, Wenbo, Wang, Dong
Format: Article
Language:English
Subjects:
Analysis
Grain boundaries
Nuclear energy
Nuclear industry
Online Access:Get full text
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Summary:UO.sub.2-BeO is an important composite nuclear fuel with high thermal conductivity. The impact of grain boundaries between UO.sub.2-UO.sub.2 and phase boundaries between UO2-BeO on the bubble evolution and the thermal conductivity in nuclear fuels is significant. In this study, we utilize a 3D phase field model to examine the influence of these boundaries on the nucleation and growth of bubbles in a bicrystalline UO.sub.2-BeO. Our simulations reveal that the diffusion of vacancies and gas atoms towards the phase boundaries results in bubbles preferentially forming at the phase boundaries. Intergranular bubbles possess an asymmetrical lectical shape due to the long-range diffusion-controlled boundary migration and the different defect production rate on the both sides. Spherical intragranular bubbles appear after the intergranular bubbles with high defects production rates and large grain size. The effective thermal conductivity decreases with the irradiation time and shows three distinct stages for systems that have both inter- and intragranular bubbles.
ISSN:0022-2461
DOI:10.1007/s10853-023-08766-z