Multiscale Mesoscale Modeling of Porosity Evolution in Oxide Fuels

Abstract The behavior of fission gas, notably accommodation within intra- and intergranular bubbles, influences the macroscopic properties and overall performance of oxide fuels. This work discusses progress to capture key fission gas-related phenomena with modern mesoscale techniques: the interaction of grain growth and irradiation by a phase-field crystal (PFC) method; overpressurized intragranular bubble migration in a vacancy gradient by a linearized phase-field model; and intergranular bubble interlinkage and percolation by the included phase model (IPM). An outlook on the impact of these models for the investigation of unit mechanisms of fission gas behavior and integration of them into fuel-performance codes is presented.