Photochemical reprocessing method

At least one specified FP ingredient is removed at first from a solution in which spent nuclear fuels are dissolved. Then, light is irradiated to the aqueous solution to control the atomic valency of at least one An ingredient of U, Pu, Np and Am. Further, the aqueous solution is brought into contact with an organic solvent to distribute each of the ingredients to an aqueous phase and an organic phase, and at least one of the An ingredients is extracted to the organic phase. Namely, removal of a specific FP ingredient reduces the absorption of light at a wavelength of λ to be irradiated to the ingredient. Since the wavelength λ is set to a wavelength value at which the Ann+ of a specified atomic valency of An as an aimed ingredient for adjustment of the atomic valency shows absorption, the removal of the specific FP ingredient increases selective light absorption. Since ions excited by absorbing ions are active compared with base ions, it is suffice to use a moderate oxidant or reducing agent which is not used for other ingredients, and a selective adjustment for atomic valency is enabled. (N.H.)