Paper
Development of a Model for Irradiation-Assisted Grain Growth for Nanocrystalline UO2
Authors
Md Ali Muntaha, Larry Aagesen, Michael Tonks
Abstract
In this work, we have developed a model for irradiation-assisted grain growth in nanocrystalline UO using the MARMOT code. We include the impact of irradiation on UO 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 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 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 fuel pellets.