Theodore Besmann1 Emily Moore1 William Wieselquist2 Srdjan Simunovic2 Jacob McMurray2

1, Univ of South Carolina, Columbia, South Carolina, United States
2, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States

The development of comprehensive, physics-based nuclear fuel performance codes requires integration of the chemical state of the fuel to allow accurate representation of a number of thermophysical properties as well as oxygen and reactive species transport and behavior. A thermodynamic equilibrium solver, Thermochimica, has been successfully coupled with the nuclear fuel performance code BISON to provide that capability. Representing the local fuel chemical state requires an accurate set of thermochemical models and parameters for fuel undergoing burnup, which for LWRs is UO2 together with fission products and relevant transuranics. Such a set of models and parameters has been under development using elemental subsystems and is being integrated into a comprehensive representation of the fuel thermo-chemical state during burnup. In this paper we will discuss the state of the art of modeling the chemistry of nuclear fuel undergoing burnup and its application in modeling of in-reactor phenomena.

This research was supported by the U.S. Department of Energy, Office of Nuclear Energy, Nuclear Energy Advance Modeling and Simulation Program.