. . . . . . . . . .    ANM 2010     3rd International Conference on Advanced Nano Materials     12-15 September 2010 - Agadir, Morocco Back    Abstract ANMM337 MESO-SCALE PHASE-FIELD MODELING ON IRRADIATION DAMAGED MATERIALS: VOID MIGRATION AND SWELLING UNDER A TEMPERATURE GRADIENT M.A. Khaleel, Yulan Li, Shenyang Hu, Xin Sun and Fei Gao  Pacific Northwest National Laboratory, Richland, WA USA . Vacancy and interstitial are two major defects produced by fission fragment and neutron irradiation in nuclear reactor components such as nuclear fuels and cladding materials. With the accumulation of these defects and their interactions with microstructures, void nucleation, growth, and volume swelling take place. At the presence of temperature gradient, voids might migrate.  In fuel cladding materials, the formation and evolution of void lattices are often observed in body-centered cubic (BCC), face-centered cubic (FCC) and hexagonal-close-packed (HCP) structural materials. These microstructure changes result in changes of thermo-mechanical properties such as thermal conductivity, elasticity, plasticity as well as structure instability including volume swelling and cracking.  In this study, we employed the meso-scale phase-field approach to investigate the migration of vacancies, interstitials and voids, and volume swelling in materials under irradiation and a temperature gradient. A phase-field model has been developed to take into account the generation rates of irradiation-induced vacancies and interstitials, their recombination, and the different mobilities of vacancies along void surface and in bulk. The dependence of single void migration velocity on surface diffusion and recombination rates, the volume swelling on interstitial mobilities and the generation rate of both vacancies and interstitials will be presented. Comparison with experimental observations will be discussed. . © nanoAC . . . . . . . . . .

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