Abstract
Zirconium (Zr) is added to uranium (U) to improve the performance of metallic fuel for fast reactor applications. This paper uses transmission electron microscopy (TEM) and atom probe tomography (APT) to investigate nanoscale clustering and fission product distribution in annular U-10Zr (in weight) metallic fuel irradiated at the Advanced Test Reactor (ATR). The results reveal variations in the shape, size, and chemical composition of clusters at different radial locations in the irradiated fuel cross-section sample. Zr-rich clusters contain higher concentration of fission products (FPs) compared to U-rich clusters, potentially due to the co-precipitation of Zr and FPs in the α-U fuel matrix during cooling at the end of life. This work complements the constituent redistribution at other higher length scale in irradiated U-10Zr metallic fuel.