Mesoscale Benchmark Demonstration, Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO₂ under Post-irradiation Thermal Annealing

Technical Report · Sun Apr 01 00:00:00 EDT 2012

DOI:https://doi.org/10.2172/1049667· OSTI ID:1049667

Li, Yulan ^[1]; Hu, Shenyang Y. ^[1]; Montgomery, Robert ^[1]; Gao, Fei ^[1]; Sun, Xin ^[1]; Tonks, Michael ^[2]; Biner, Bulent ^[2]; Millet, Paul ^[2]; Tikare, Veena ^[3]; Radhakrishnan, Balasubramaniam ^[4]; Andersson, David ^[5]

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1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
2. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
4. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
5. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

A study was conducted to evaluate the capabilities of different numerical methods used to represent microstructure behavior at the mesoscale for irradiated material using an idealized benchmark problem. The purpose of the mesoscale benchmark problem was to provide a common basis to assess several mesoscale methods with the objective of identifying the strengths and areas of improvement in the predictive modeling of microstructure evolution. In this work, mesoscale models (phase-field, Potts, and kinetic Monte Carlo) developed by PNNL, INL, SNL, and ORNL were used to calculate the evolution kinetics of intra-granular fission gas bubbles in UO₂ fuel under post-irradiation thermal annealing conditions. The benchmark problem was constructed to include important microstructural evolution mechanisms on the kinetics of intra-granular fission gas bubble behavior such as the atomic diffusion of Xe atoms, U vacancies, and O vacancies, the effect of vacancy capture and emission from defects, and the elastic interaction of non-equilibrium gas bubbles. An idealized set of assumptions was imposed on the benchmark problem to simplify the mechanisms considered. The capability and numerical efficiency of different models are compared against selected experimental and simulation results. These comparisons find that the phase-field methods, by the nature of the free energy formulation, are able to represent a larger subset of the mechanisms influencing the intra-granular bubble growth and coarsening mechanisms in the idealized benchmark problem as compared to the Potts and kinetic Monte Carlo methods. It is recognized that the mesoscale benchmark problem as formulated does not specifically highlight the strengths of the discrete particle modeling used in the Potts and kinetic Monte Carlo methods. Future efforts are recommended to construct increasingly more complex mesoscale benchmark problems to further verify and validate the predictive capabilities of the mesoscale modeling methods used in this study.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Nuclear Fuel Cycle and Supply Chain. Fuel Cycle Research and Development Program
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1049667
• Report Number(s): PNNL--21295; FCR&D-MDSM-2012-000098; NT0108060
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
ANNEALING
ATOMS
BENCHMARKS
BUBBLE GROWTH
BUBBLES
DEFECTS
DIFFUSION
EFFICIENCY
FISSION
FREE ENERGY
Fission gas bubbles
KINETICS
Kinetic Monte Carlo approach
MICROSTRUCTURE
MONTE CARLO METHOD
Mesoscale benchmark
Phase-field approach
Post-irradiation thermal annealing.
Potts Model
Uranium dioxide
VACANCIES