Mechanism of Oxygen Diffusion in UO₂-Zr Dispersion Plate-type Fuel

The oxidation of UO₂-Zr dispersion plate-type fuel consists of two processes: Zr-water chemical reaction and oxygen diffusion from dispersed UO₂ fuel particles in fuel meat at high temperature. The oxygen diffusion equation in one-dimensional spherical coordinate was calculated directly in this paper to acquire analytical solution of diffusion intensity from UO₂ fuel particles to Zr fuel matrix, and analytical solutions suit well with experimental results. A new UO₂-Zr oxidation model which combines Zr-water chemical reaction and oxygen diffusion process in plate-type fuel was developed in this paper and the calculation results indicate different oxidation structures, larger oxygen concentration and smaller oxygen absorption from water in plate-type fuel supply theoretical fundamental for severe accident research on the early phase performance of UO₂-Zr dispersion plate-type fuel.