Defect cluster and nonequilibrium gas bubble associated growth in irradiated UMo fuels – a cluster dynamics and phase field model

Journal Article · Tue Dec 15 04:00:00 EST 2020 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2020.152441· OSTI ID:1668710

Hu, Shenyang ^[1]; Setyawan, Wahyu ^[1]; Beeler, Benjamin ^[2]; Burkes, Douglas ^[1]

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1. BATTELLE (PACIFIC NW LAB)
2. Idaho national laboratory

Irradiation examination shows that gas bubble swelling kinetics is much faster after irradiation-induced recrystallization than that prior recrystallization in UMo fuels. It implies that gas bubbles in coarse grains and small recrystallized grains have different growth behavior. In this work, a phase-field model of gas bubble evolution integrating microstructure dependent cluster dynamics has been developed, for the first time, to study the gas bubble swelling behavior in the recrystallization zone of UMo fuels. Generation, diffusion, reaction, sink, emission and clustering of vacancies and interstitials are described by the cluster dynamics model while a phase-field model is used to describe the evolution of non-equilibrium gas bubbles including nucleation and growth. With the coupled model, the effect of defect generation rate, clustering rate, interstitial emission and sink rates on grain boundaries on the gas bubble evolution are systematically simulated. A set of model parameters (defect generation rate, clustering rate, interstitial emission and sink rates) is determined by comparing measured and simulated gas bubble swelling kinetics. The results demonstrate that interstitial clustering is one of the important physical mechanisms which results in a fast gas bubble swelling kinetics in the recrystallization zone. The developed model can also be extended to study the associated growth of defect and second phase precipitates often observed in irradiated materials.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1668710
• Report Number(s): PNNL-SA-149433
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Vol. 542
• Country of Publication: United States
• Language: English