TY - JOUR
T1 - Phase-field modeling of fission gas bubble growth on grain boundaries and triple junctions in UO 2 nuclear fuel
AU - Aagesen, Larry K.
AU - Schwen, Daniel
AU - Tonks, Michael R.
AU - Zhang, Yongfeng
N1 - Funding Information:
This work was funded by the Department of Energy Nuclear Energy Advanced Modeling and Simulation program. This manuscript has been authored by Battelle Energy Alliance, LLC under Contract No. DE-AC07-05ID14517 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.
Publisher Copyright:
© 2019
PY - 2019/4/15
Y1 - 2019/4/15
N2 - A phase-field model of fission gas bubble evolution was developed and applied to gain an improved understanding of the microstructure-level processes leading to fission gas release from nuclear fuel, and to inform engineering-scale fission gas release models. The phase-field model accounts for multiple fuel grains and fission gas bubbles and tracks the local concentration of vacancies and gas atoms. The model was used to simulate the growth of grain boundary and triple junction bubbles in a hexagonal periodic 3D grain structure. The fractional coverage of the triple junctions and the number of fully saturated triple junctions (that is, triple junctions fully covered by the gas phase) was calculated, and correlations were developed between these quantities and the grain boundary coverage. The effects of initial triple junction bubble density, vacancy source strength, and bubble semi-dihedral angle on triple junction coverage and saturation were evaluated. High initial triple junction coverage and high bubble semi-dihedral angle can lead to triple junction saturation well before grain boundary percolation. The implications of these findings for engineering-scale fuel performance modeling are discussed.
AB - A phase-field model of fission gas bubble evolution was developed and applied to gain an improved understanding of the microstructure-level processes leading to fission gas release from nuclear fuel, and to inform engineering-scale fission gas release models. The phase-field model accounts for multiple fuel grains and fission gas bubbles and tracks the local concentration of vacancies and gas atoms. The model was used to simulate the growth of grain boundary and triple junction bubbles in a hexagonal periodic 3D grain structure. The fractional coverage of the triple junctions and the number of fully saturated triple junctions (that is, triple junctions fully covered by the gas phase) was calculated, and correlations were developed between these quantities and the grain boundary coverage. The effects of initial triple junction bubble density, vacancy source strength, and bubble semi-dihedral angle on triple junction coverage and saturation were evaluated. High initial triple junction coverage and high bubble semi-dihedral angle can lead to triple junction saturation well before grain boundary percolation. The implications of these findings for engineering-scale fuel performance modeling are discussed.
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U2 - 10.1016/j.commatsci.2019.01.019
DO - 10.1016/j.commatsci.2019.01.019
M3 - Article
AN - SCOPUS:85060651490
VL - 161
SP - 35
EP - 45
JO - Computational Materials Science
JF - Computational Materials Science
SN - 0927-0256
ER -