2, Idaho National Laboratory, Idaho Falls, Idaho, United States
Alloys of uranium (U), plutonium (Pu), and zirconium (Zr) are likely metal fuel candidates for sodium cooled fast reactors. However, our physical understanding of this ternary system is limited. In this work, we use a combination of mesoscale simulation and experimental characterization to study the U-Pu-Zr system. We present our phase field model that captures the behavior of the 13 dominant phases of the ternary system using published free energies for the system. We then demonstrate where comparison with experiments shows weaknesses in the free energies. Finally, we compare the model predictions with experimental data to show where future work is needed.