Abstract: Provided is a method that can remove fission products in a spent electrolyte produced in a dry reprocessing process by an easy operation and can vitrify the fission products easily, the fission products including not only the fission products that generate precipitate but also the fission products that generate no precipitate. A spent electrolyte produced in a dry reprocessing process is subjected to a phosphate conversion processing to obtain a processing target substance; the processing target substance is passed through a separating material 10 including an iron phosphate glass at a temperature of not more than a softening point of the iron phosphate glass in order to remove insoluble fission products included in the processing target substance by filtration with the separating material and to sorb fission products in solution to the separating material for separation; and the iron phosphate glass holding the fission products is used as a waste vitrification material.

Abstract: Provided is a method that can remove fission products in a spent electrolyte produced in a dry reprocessing process by an easy operation and can vitrify the fission products easily, the fission products including not only the fission products that generate precipitate but also the fission products that generate no precipitate. A spent electrolyte produced in a dry reprocessing process is subjected to a phosphate conversion processing to obtain a processing target substance; the processing target substance is passed through a separating material 10 including an iron phosphate glass at a temperature of not more than a softening point of the iron phosphate glass in order to remove insoluble fission products included in the processing target substance by filtration with the separating material and to sorb fission products in solution to the separating material for separation; and the iron phosphate glass holding the fission products is used as a waste vitrification material.

Abstract: Fluorine or a fluorine compound is subjected to a reaction with a spent oxide fuel to produce fluorides of uranium and plutonium, and recovering the fluorides using a difference in volatility behavior. The method includes steps of: subjecting a mixture of UO2 and PuO2 with hydrogen fluoride mixed with hydrogen to HF-fluorinate uranium and plutonium into UF4 and PuF3; subjecting UF4 and PuF3 with a fluorine gas to F2-fluorinate uranium and plutonium into UF6 and PuF6; and fractionating UF6 and PuF6 using a difference in phase change of obtained UF6 and PuF6, removing a part of UF6, and volatilizing the remaining UF6 and PuF6 at the same time. By such a reprocessing method, PuF4 hard to undergo a reaction is prevented from being formed as an intermediate fluoride, the material of a reactor is hard to be corroded, and a consumption of expensive fluorine gas is reduced.

Abstract: Fluorine or a fluorine compound is subjected to a reaction with a spent oxide fuel to produce fluorides of uranium and plutonium, and the fluorides are recovered using a difference in volatility behavior. The spent oxide fuel is subjected to a reaction with an HF gas, whereby uranium, plutonium and most impurities are converted into solid fluorides having low valences or remained as oxides to inhibit volatilization thereof, and then in an F2 fluorination step, the HF fluorination product is subjected to a reaction with a fluorine gas in two stages: one at a low temperature and the other at a high temperature, whereby a certain amount of gaseous uranium and volatile impurities are separated with plutonium kept in a solid form in the first stage, and mixed fluorides of remaining uranium and plutonium are fluorinated into hexafluorides at the same time in the second stage. By such a reprocessing method, plutonium enrichment can be adjusted, uranium and plutonium can be purified, and steps are simplified as well.

Abstract: Fluorine or a fluorine compound is subjected to a reaction with a spent oxide fuel to produce fluorides of uranium and plutonium, and recovering the fluorides using a difference in volatility behavior. The method includes steps of: subjecting a mixture of UO2 and PuO2 with hydrogen fluoride mixed with hydrogen to HF-fluorinate uranium and plutonium into UF4 and PuF3; subjecting UF4 and PuF3 with a fluorine gas to F2-fluorinate uranium and plutonium into UF6 and PuF6; and fractionating UF6 and PuF6 using a difference in phase change of obtained UF6and PuF6, removing a part of UF6, and volatilizing the remaining UF6 and PuF6 at the same time. By such a reprocessing method, PuF4 hard to undergo a reaction is prevented from being formed as an intermediate fluoride, the material of a reactor is hard to be corroded, and a consumption of expensive fluorine gas is reduced.

Abstract: Fluorine or a fluorine compound is subjected to a reaction with a spent oxide fuel to produce fluorides of uranium and plutonium, and the fluorides are recovered using a difference in volatility behavior. The spent oxide fuel is subjected to a reaction with an HF gas, whereby uranium, plutonium and most impurities are converted into solid fluorides having low valences or remained as oxides to inhibit volatilization thereof, and then in an F2 fluorination step, the HF fluorination product is subjected to a reaction with a fluorine gas in two stages: one at a low temperature and the other at a high temperature, whereby a certain amount of gaseous uranium and volatile impurities are separated with plutonium kept in a solid form in the first stage, and mixed fluorides of remaining uranium and plutonium are fluorinated into hexafluorides at the same time in the second stage. By such a reprocessing method, plutonium enrichment can be adjusted, uranium and plutonium can be purified, and steps are simplified as well.

Abstract: In a dry chemical reprocessing method, uranium type elements are electrolytically refined continuously. Molten cadmium in which these uranium type elements are dissolved is transferred to a rotating cathode electrolysis tank 30 for performing electrolytic refining. The rotating cathode electrolysis tank 30 is filled with molten cadmium, and a mixture of potassium chloride and lithium chloride. In the salt phase are placed a rotating cathode 32 and a receiving dish 36 for uranium type elements which deposit at the cathode, while in the molten cadmium phase a fixed anode 42 is installed. When uranium type elements deposited at the rotating cathode 32 have grown to at least a predetermined size, they are scraped off by a scraper 34 and collect in a receiving dish 36. These uranium type elements are sent to a U/salt separating tank 50 where uranium is separated from salts.

Abstract: A method of converting uranium dioxide into a metallic uranium lump is provided The method comprises mixing a reducing agent comprised of metallic calcium, a slag solvent comprised of calcium chloride and a eutectic comprised of at least one member selected from the group consisting of barium chloride, lithium chloride, sodium chloride and potassium chloride into uranium dioxide to obtain a mixture, heating the mixture at a temperature not below the melting point of metallic uranium, separating resulting molten metallic uranium from a resulting molten slag based on a difference in specific gravity, and cooling the molten metallic uranium to produce metallic uranium as a solid lump.