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arXiv · 2512.11289

Development of a Model for Irradiation-Assisted Grain Growth for Nanocrystalline UO2

Md Ali Muntaha·Larry Aagesen·Michael Tonks
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Abstract

In this work, we have developed a model for irradiation-assisted grain growth in nanocrystalline UO$_2$ using the MARMOT code. We include the impact of irradiation on UO$_2$ grain growth by coupling a phase field grain growth model with a heat conduction simulation that features a random heat source representing thermal spikes. Our model parameters have been calibrated against experimental measurements at 300 K. The calibrated model predicts grain growth in an irradiated UO$_2$ thin film that compares well with experimental data at 50 K. These results suggest that thermal spikes are the major cause of the irradiation-assisted grain growth observed in the UO$_2$ experiments. They also indicate that irradiation-assisted grain growth is only significant with average grain sizes less than 35 nm, and thus can be neglected when considering fuel performance of typical UO$_2$ fuel pellets.

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Md Ali Muntaha, Larry Aagesen, Michael Tonks. 2025-12-12. Development of a Model for Irradiation-Assisted Grain Growth for Nanocrystalline UO2. https://arxiv.org/abs/2512.11289

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