| Abstract Scope |
Blister formation in monolithic U–Mo nuclear fuels is governed by complex, interrelated phenomena, including radiation-induced defect accumulation, phase-specific swelling behaviors, evolving mechanical properties of Zr, UZr₂, and U–Mo phases, and heterogeneous microstructures. These factors collectively influence local stress states, enhance defect transport, and drive gas bubble evolution.
In this work, we develop a mesoscale finite-deformation model focused on a representative volume near the Zr/U–Mo interface. The model incorporates key irradiation-induced phenomena: large volumetric swelling, swelling-dependent mechanical softening in U–Mo, and stress-free strains in Zr, UZr₂, and U–Mo phases. To investigate gas-driven blistering, the model introduces structural defects and accounts for evolving thermo-mechanical properties and defect mobility. We systematically examine the coupling between stress fields, defect transport, and gas bubble pressure under irradiation. The results elucidate critical conditions for blister nucleation and growth, demonstrating the model’s capability to predict fuel performance risks related to structural defects and irradiation effects.
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