Interdiffusion in uranium-zirconium solid solutions

Interdiffusion coefficients in the (gamma-U, beta-Zr) solid solutions have been measured in the temperature range of 973 to 1223 K and in the Zr concentration range of 0.1 to 0.95 atomic fraction. The data measured at lower temperature than 1223 K have shown notable depression in the Zr concentration range of 0.2 to 0.4 atomic fraction. The dependencies of the obtained data on alloy composition and temperature are consistent with variation of the thermodynamic factor which is calculated based on the evaluation of the activity coefficient in the U-Zr system. The interdifusion coefficient in the neighborhood of the Zr atomic fraction of 0.3 cannot be expressed by a single set of a frequency factor and an activation energy because of the significant influence of the thermodynamic factor on the interdiffusivity in the U-Zr solid solutions.