Abstract: Due to the strong radioactivity of spent nuclear fuel, radiation chemistry is accompanied in spent fuel reprocessing. Although the direct effects of ionizing radiation on the extractant itself are usually not significant, the reactive radicals generated by the interaction of ionizing irradiation with the solvent molecules in water or oil phases may attack the extractant. The transient species produced by solvent radiolysis may react with metal ions and change their oxidation state, resulting in the decrease of their extraction efficiencies or partition ratios. The nitrous acid produced by nitric acid radiolysis in the aqueous phase has an important influence on the oxidation state of the metal ion, and other radicals such as •NO  ₃ also can deteriorate the solvent. In advanced nuclear energy systems, the radioactivity is stronger because of the higher burnup of the nuclear fuel. The concentration of nitric acid used to dissolve spent fuel is also increased. Therefore, it is now a good opportunity to carry out radiation chemistry studies for advanced fuel cycles, but obviously with great challenge too. This review aims to discuss radiation chemistry related to researches on reprocessing (solvent extraction) in the past decade, especially the radiolysis of diluent and the radiation stability of new extractants.