Abstract
Actinide nanoparticles (NPs) are widely recognized for their role as a potentially highly mobile form of radioactive contaminants in the environment. In recent years, research has increasingly focused on elucidating their formation mechanisms, atomic structure, and physicochemical properties. The application of synchrotron radiation techniques is central to the detailed characterization of their atomic structure and oxidation state. This review retraces the evolution of actinide NPs research and highlights recent achievements enabled by high-energy-resolution fluorescence-detected X-ray absorption near edge structure, used in correlation with complementary synchrotron-based methods.