Evaluation of The Thermophysical Properties and Microstructure of UPu₂₄Zr₁₅ Metallic Fuel

Featuring high burn-up, high fissile and fertile isotopic density, inherent safety characteristics, and favorable thermal response, actinide transmutation metallic fuels are considered to be among the most promising fuel classes for next generation fast reactors. During reactor operation, it is anticipated that fluctuations in chemical potential along the temperature gradient will lead to migration and redistribution of constituents between radial zones of the cylindrical fuel pin, resulting in compositional inhomogeneity and hence unpredictable fuel performance. Limited experimental fuel performance data is available for fuel selection and certification, therefore different compositions of options uranium-plutonium-zirconium (UPu- Zr) alloys have been investigated. Several complementary techniques, including scanning and transmission electron microscopy (SEM and TEM, respectively), differential scanning calorimetry (DSC), and laser flash diffusivity (LFD) techniques were used to characterize the phase distribution, microstructure, and thermophysical properties of unirradiated U-Pu-Zr fuels in both the as-cast and annealed condition. This information is necessary to understand the irradiated microstructure, properties, and performance of U-Pu-Zr fuels