SIMULATION OF GRAIN-GROWTH AND PORE MIGRATION IN A THERMAL-GRADIENT

The Potts Monte Carlo simulation was used to simulate microstructural evolution in uranium dioxide fuel rods, During service, grain growth, pore migration, and thermal segregation of the pores and UO2 occur in the rods in a thermal gradient. In this investigation, we developed a model which simulates simultaneous grain growth, pore migration, and t hermal segregation of the pores and UO2 in a temperature gradient, Gra in growth in a thermal gradient was simulated using the Monte Carlo Po tts model technique developed by Anderson, Srolovitz, and co-workers. Pore migration was simulated using conserved dynamics with minimum-ene rgy exchanges at a finite temperature, A temperature gradient was intr oduced into the model via interfacial mobility gradient, Finally, ther mal segregation of the pores and UO2 was achieved by introducing a hea t of migration term, Delta E-t, which biased the motion of porosity to the high-temperature region, The development of this model is describ ed and the incorporation of the proper physics of pore migration and t hermal segregation is discussed.