Multiscale Model for Simulating Fission-Induced Recrystallization in U-Mo Alloy

Journal Article · Wed Jun 15 04:00:00 EDT 2016 · Transactions of the American Nuclear Society

OSTI ID:22992102

Liang, Linyun; Mei, Zhi-Gang; Yacout, Abdellatif M. ^[1]

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1. Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

U-Mo alloy is one of the most promising fuels for the future high performance research and test reactors due to its high uranium loading density and stable irradiation behavior. However, a major concern to its qualification is the fuel swelling at high fission density due to the formation of large fission-gas bubbles. The fission-induced recrystallization further expedites the formation and growth of gas bubbles. So far, the exact mechanism of recrystallization is still unclear. One possible driving force for recrystallization is the production of point defects and interstitial loops due to irradiation. Following this, we developed a multi-scale model by integrating the rate-theory and phase-field models to study microstructural evolutions in irradiated U-Mo alloy, i.e., fission-induced gas bubble evolution and recrystallization. Density function theory (DFT) calculations are utilized to predict the defect formation energies, diffusivities of defects, the interfacial energy of gas bubble, and the elastic constants of U-Mo alloy, etc. The dislocation density evolution is predicted by the rate-theory developed by Jeff. The grain subdivision occurs once the dislocation density is above a critical value. The grain growth coupled with gas bubbles evolution is modeled using a multi-phase phase-field model. The effects of fission rate and initial grain microstructure on the recrystallization process are systematically investigated. The simulated dislocation density, sub-grain size distribution, and volume fraction of the recrystallization grains under different fission density are comparable with experimental data. (authors)

• OSTI ID: 22992102
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Journal Issue: 1 Vol. 114; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
97 MATHEMATICS AND COMPUTING
DISLOCATIONS
FISSION
FISSION PRODUCTS
FORMATION HEAT
GRAIN GROWTH
GRAIN SIZE
INTERSTITIALS
IRRADIATION
PERFORMANCE
RECRYSTALLIZATION
RESEARCH AND TEST REACTORS
SCALE MODELS
SIMULATION
URANIUM