Method of recovering uranium and transuranic elements from spent nuclear fuel

摘要

The steps for recovering uranium and transuranic elements are simplified, and the generation of waste solvent and waste materials is suppressed. Spent nuclear fuel is dissolved in nitric acid (S100) and the resulting solution is subjected to electrolytic oxidation so that U, Np, Pu, Am is oxidized to VI using Ce as oxidation catalyst. The solution is cooled, and nitrates of valence VI thereby deposit as crystals and are separated from the mother liquor (S104). The mother liquor is heated and concentrated (S114). The mixed crystalline deposit is dissolved in nitric acid (S106), uranyl nitrate is deposited alone by cooling (S108), and the crystals are separated from the U, Np, Pu, Am mixed solution (S110). The uranyl nitrate is dissolved in nitric acid (S112), and the heated and concentrated mother liquor is added to it to prepare another mixed solution. This mixed solution is then subjected to electrolytic oxidation to oxidize the remaining U, Np, Pu, Am to valence VI, and the solution is cooled so that U, Np, Pu, Am are coprecipitated with uranyl nitrate as crystals, and can be separated from high level radioactive effluent (S118) .