ИСТИНА

Nuclear waste and fuel processing implies specialized ligands along with other organic compounds at certain steps of the treatment. Despite their auxiliary role in separation, these substances are used in significant concentrations, making their radiation-induced chemistry significantly impactful on the overall efficacy of the process. Most of these compounds are organic acids, particularly carboxylic and hydroxamic acids. For instance, citric and oxalic acids are integral to the CITROX process and other U and Pu separations, as well as soil radiation decontamination. Glycolic acid is employed in Sr and Cs, and actinides separations, while acetohydroxamic and lactic acids are crucial in the advanced PUREX and TALSPEAK processes, respectively. Given that these compounds are used in an aqueous environment, the primary radiation-induced damage likely arises from reactions with water radiolysis products, such as hydrated electrons, hydrogen atoms, and hydroxyl radicals. It is essential for radiation chemistry of the separation process to achieve a thorough understanding of the structures of radicals derived from these substances, as well as their interconversion features and decay rates. This study aims to investigate the structures and decay rates of OH-induced radicals derived from acetohydroxamic (AHA), citric (CA), glycolic (GA), lactic (LA), and oxalic acids (OA) generated by Fenton-like approach in the EPR cavity. The extensive quantum chemical calculations performed to estimate EPR spectral parameters, potential structures, and interconversion between radicals. The obtained experimental data enable an evaluation of the well-established B3LYP functional and the newly devised ab initio LPBE functional, comparing their efficacy in predicting EPR parameters. The role of structure on the decay kinetics of radicals is discussed.