METHOD FOR RECOVERING TRANSURANIUM ELEMENT FROM SPENT NUCLEAR FUEL

• Main Authors: KIHARA YOSHIYUKI, TSUDOKORO AKIO, OKADA TAKASHI
• Format: Patent
• Language: English
• Published: 23.10.1998
• Edition: 6
• Subjects: APPARATUS THEREFOR; CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATERTREATMENT OR WASTE MANAGEMENT; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; DECONTAMINATION ARRANGEMENTS THEREFOR; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTIONOF COMPOUNDS OR NON-METALS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INORGANIC CHEMISTRY; METALLURGY; NUCLEAR ENGINEERING; NUCLEAR PHYSICS; NUCLEAR REACTORS; PHYSICS; PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULARRADIATION OR PARTICLE BOMBARDMENT; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; TREATING RADIOACTIVELY CONTAMINATED MATERIAL

PROBLEM TO BE SOLVED: To simplify the recovery step of transuraunium element and reduce waste solvent and wastes. SOLUTION: A spent nuclear fuel is dissolved in a nitrate acid (S100), the dissolved liquid is subject to electrolitic oxidation, and U, Np, Pu, and Am are oxidized at hexa valence by using Ce as an oxidizing catalyst, and further they are cooled to crystallize a hexavalent nitrate salt and separate it from a mother liquor (S104). The mother liquor is heated and condensed (S114). The separated mixed deposit is dissolved in a nitrate once (S106) and only an uranyl nitrate is deposited by cooling it (S108), and then it is separated from a mixing liquid of U, Np, Pu, and Am (S110). The uranyl nitrate is dissolved in a nitrate acid (S112). The nitrate solution is added with the heated and condensed mother liquor to prepare a mixing solution. The mixing solution is electrolytically oxidixed so as to oxidize the remaining U, Np, Pu, and Am at hexa valence and cool them, thereby precipitate the remaining U, Np, Pu, and Am together thanks to uranyl nitrate and separating them from high-level radiation waste.