Dr. Srdjan Simunovic
Computational Sciences and Engineering Division
Oak Ridge National Laboratory

Modeling and Simulation of Oxygen Transport in High Burnup LWR Fuel

ABSTRACT: A formulation for oxygen transport in uranium dioxide nuclear fuel that accounts for the effects of irradiation has been developed. The overall simulation combines the evolving isotopic composition, thermochemistry, and oxygen transport in irradiated fuel. The driving forces for oxygen transport are computed from local thermodynamic equilibrium calculations and account for the effects of temperature gradients and composition, including fission products. The proposed method provides a mechanism for including complex thermodynamic models of nuclear fuel in modeling of mass redistribution, and alleviates difficulties associated with the common thermo-diffusion formulation. The transport model has been implemented within the nuclear fuel performance code BISON utilizing the thermochemistry code Thermochimica, with burnup calculations provided by the ORIGEN isotopic transmutation code.

BIOGRAPHY: Srdjan Simunovic is a distinguished staff member in the Computational Engineering and Energy Sciences Group, Computational Sciences and Energy Division. He has been conducting research and development in the area of computational materials science and continuum mechanics. The scope involved both fundamental and applied research funded by government agencies and private industry. His prior work includes computational modeling of structural crash and impact, modeling of material response at high strain rates, and development of material and structural tests for high speeds of loading. His current research projects are on modeling of additive manufacturing materials and processes, thermodynamics and kinetics of materials, multi-physics modeling of nuclear materials, shell element formulations for structural applications, and development of time-parallel solvers for differential algebraic equations.