GB2461370A - Spent nuclear fuel reprocessing methods - Google Patents

Spent nuclear fuel reprocessing methods Download PDF

Info

Publication number
GB2461370A
GB2461370A GB0909309A GB0909309A GB2461370A GB 2461370 A GB2461370 A GB 2461370A GB 0909309 A GB0909309 A GB 0909309A GB 0909309 A GB0909309 A GB 0909309A GB 2461370 A GB2461370 A GB 2461370A
Authority
GB
United Kingdom
Prior art keywords
precipitate
electrolysis
oxalic acid
cathode
uranium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB0909309A
Other versions
GB2461370B (en
GB0909309D0 (en
Inventor
Koji Mizuguchi
Reiko Fujita
Kouki Fuse
Hitoshi Nakamura
K Utsunomiya
Akihiro Kawabe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toshiba Corp filed Critical Toshiba Corp
Publication of GB0909309D0 publication Critical patent/GB0909309D0/en
Publication of GB2461370A publication Critical patent/GB2461370A/en
Application granted granted Critical
Publication of GB2461370B publication Critical patent/GB2461370B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • GPHYSICS
    • G21NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21CNUCLEAR REACTORS
    • G21C19/00Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
    • G21C19/42Reprocessing of irradiated fuel
    • G21C19/44Reprocessing of irradiated fuel of irradiated solid fuel
    • G21C19/46Aqueous processes, e.g. by using organic extraction means, including the regeneration of these means
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25CPROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C1/00Electrolytic production, recovery or refining of metals by electrolysis of solutions
    • C25C1/22Electrolytic production, recovery or refining of metals by electrolysis of solutions of metals not provided for in groups C25C1/02 - C25C1/20
    • GPHYSICS
    • G21NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21FPROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/04Treating liquids
    • G21F9/06Processing
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25CPROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/34Electrolytic production, recovery or refining of metals by electrolysis of melts of metals not provided for in groups C25C3/02 - C25C3/32
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00Energy generation of nuclear origin
    • Y02E30/30Nuclear fission reactors
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/50Reuse, recycling or recovery technologies

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Plasma & Fusion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

A spent fuel reprocessing method comprises: dissolving the spent fuel in a nitric acid solution; reducing the plutonium within the solution to a trivalent state; collecting uranium oxide by bringing the fuel into contact with an organic solvent and extracting hexavalent uranium by means of an extraction agent; and causing the minor actinides and fissure products remaining in the nitric acid solution to precipitate together as oxalic acid precipitate. In a first embodiment, the oxalic acid precipitate is converted into chlorides by adding hydrochloric acid; anhydrous chlorides are then produced by dehydrating the chlorides in a flow of inert gas; before the anhydrous chlorides are dissolved into molten salt. Alternatively, in a second embodiment (see Figure 3), the oxalic acid precipitate is dehydrated and converted into precipitate oxides in an oxidation atmosphere; before being immersed in a mixture of molten salts of chlorides of alkali metals or alkaline earth metals. Uranium, plutonium and minor actinides are subsequently collected by electrolysis.

Description

SPENT FUEL REPROCESSING METHOD
FIELD OF THE INVENTION
The present invention relates to a spent fuel reprocessing method comprising a step of collecting uranium (U), plutonium (Pu) and minor actinides (MA) from spent oxide nuclear fuel.
DESCRIPTION OF THE RELATED ART
The Purex process is a known typical process for reprocessing spent fuel produced from nuclear power plants so as to refine and collect useful substances contained in the spent fuel in order to reutilize them as fuel and isolate unnecessary fission products. Spent fuel contains alkali metal (AM) elements, alkaline-earth metal (AEM) elements and platinum group elements as fission products (FP) besides transuranic elements (TRU) such as uranium and plutonium.
In the Purex process, spent fuel is dissolved in nitric acid solution and subsequently fission products are isolated in a first extraction step. Thereafter, U and Pu are separated from each other in a separation step and respectively subjected to a U purification process and a Pu purification process. Then, the Pu solution and the U solution are put together and subjected to mixture and denitration so that it is not possible to collect Pu alone.
Since U and Pu are temporarily separated from each other in the separation step of the Purex process, nuclear non-proliferability is not absolutely secured.
Therefore, there is a demand for a reprocessing process realized by partly modifying the Purex process so as to make it impossible to collect Pu alone and realize a high degree of nuclear non-proliferability.
Meanwhile, the high level liquid waste produced from a Purex process contains U and Pu to a small extent and minor actinides (Np: Neptunium, Am: Americium, Cm: Curium, etc.) to a large extent. The aqua-pyro process is known to collect such transuranic elements (Pu and minor actinides) in combination by applying a technique of oxalic acid precipitation -conversion to chloride -molten salt electrolysis to high-level liquid waste (Patent Documents 1 and 2: Japanese Patent No. 2,809,819 Publication and Japanese Patent No. 3,319,657 Publication). The entire content of which is incorporated herein by reference. With the aqua-pyro process, Pu and U are made to accompany minor actinides and collected in combination with each other. In other words, Pu is not collected alone by itself.
In view of the above-identified problem of the prior art,it is therefore the object of the present invention to provide a spent fuel reprocessing method that can isolate most of the uranium contained in spent fuel solution and collect it as light water reactor fuel and, at the same time, can collect Pu and minor actinides with U so as to make them utilizable as metal fuel for a fast reactor in order to ensure a high degree of nuclear non-proliferability.
SUMMARY OF THE INVENTION
In order to attain the object, according to an aspect of the present invention, there is provided a spent fuel reprocessing method comprising: a disassembly/shear step of disassembling and shearing spent oxide nuclear fuel; a dissolution step of dissolving the fuel subjected to the disassembly/shear step in nitric acid solution; an electrolysis/valence adjustment step of reducing plutonium to trivalent, maintaining the pentavalent of neptunium for the fuel subjected to the dissolution step; a uranium extraction step of collecting uranium oxide by bringing the fuel subjected to the electrolysis/valence adjustment step into contact with organic solvent and extracting hexavalent uranium by means of an extraction agent; an oxalic acid precipitation step of causing the minor actinides and the fissure products remaining in the nitric acid solution after the uranium extraction step to precipitate together as oxalic acid precipitate by means of an oxalic acid precipitation method; a chlorination step of converting the oxalic acid precipitate into chlorides by adding hydrochloric acid to the oxalic acid precipitate; a dehydration step of synthetically producing anhydrous chlorides by dehydrating the chlorides in a flow of reductive inert gas; and a molten sait electrolysis step of dissolving the anhydrous chlorides into molten salt and collecting uranium, plutonium and minor actinides at the cèthode by electrolysis.
According to another aspect of the present invention, there is provided a spent fuel reprocessing method comprising: a disassembly/shear step of disassembling and shearing spent oxide nuclear fuel; a dissolution step of dissolving the fuel subjected to the disassembly/shear step in nitric acid solution; an electrolysis/valence adjustment step of reducing plutonium and neptunium respectively to trivalent and pentavalent for the fuel subjected to the dissolution step; a uranium extraction step of collecting uranium oxide by bringing the fuel subjected to the electrolysis/valence adjustment step into contact with organic solvent and extracting hexavalent uranium by means of an extraction agent; an oxalic acid precipitation step of causing the minor actinides and the fissure products remaining in the nitric acid solution after the uranium extraction step to precipitate together as oxalic acid precipitate by means of an oxalic acid precipitation method; an oxidation/dehydration step of dehydrating the oxalic acid precipitate and subsequently converting it into precipitate oxides in an oxidation atmosphere; and an electrolysis/reduction step of immersing the precipitate oxides in a mixture of molten salts obtained by dissolving alkali metal oxjdes in molten salts of chlorides of alkali metals or a mixture of molten salts obtained by dissolving alkaline-earth metal oxides in molten salts of chlorides of alkaline-earth metals, bringing the precipitate oxides into contact with a cathode to drawn out oxygen ions in the precipitate oxides, removing the oxygen ions as oxygen gas or carbon dioxide gas at the side of an anode in the molten salts and collecting uranium, plutonium and minor actinides in the precipitate oxides at the cathode.
Thus, according to the present invention, it is possible to isolate most of the uranium from spent fuel solution and collect it as light water reactor fuel, while it is possible to collect Pu and minor actinides with U so as to make them utilizable as metal fuel for a fast reactor. As Pu is not collected alone by itself and Pu and minor actinides are collected with U, the present invention can ensure a high degree of nuclear non-proliferability.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of the present invention will become apparent from the discussion hereinbelow of specific, illustrative embodiments thereof presented in conjunction with the accompanying drawings, in which: FIG. I is a flowchart of spent fuel reprocessing method according to a first embodiment of the present invention; FIG. 2 is a schematic sectional elevational view of an apparatus that can be employed for an electrolysis/valence adjustment step of spent fuel reprocessing method according to the first embodiment of the present invention; FIG. 3 is a graph showing some of the results of measurement of the initial value of the electrode potential and that of the current density in the electrolysis/valence adjustment step of spent fuel reprocessing method according to the first embodiment of the present invention; FIG. 4 is a graph showing some of the results of measurement of the change with time of the current density when the electrolysis potential is held to -1 00 mV relative to a reference electrode, which is a silver/silver salt electrode, in the electrolysis/valence adjustment step of spent fuel reprocessing method according to the first embodiment of the present invention; FIG. 5 is a flowchart of spent fuel reprocessing method according to a second embodiment of the present invention; and FIG. 6 is a schematic sectional elevational view of an apparatus that can be employed for the electrolysis/reduction step of spent fuel reprocessing method according to the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, the present invention will be described by referring to the accompanying drawings that illustrate preferred embodiments of spent fuel reprocessing method according to the present invention.
[First Embodiment] The first embodiment of spent fuel reprocessing method according to the present invention will be described below by referring to FIGS. I and 2.
FIG. I is a flowchart of spent fuel reprocessing method according to a first embodiment of the present invention.
Referring to FIG. 1, first, spent oxide fuel 1 is disassembled and sheared in a disassembly/shear step 2. Subsequently, all the spent oxide fuel is dissolved by nitric acid in a dissolution step 3.
At this time, U exists in a hexavalent state whereas Pu exists in a tetravalent state.
Thereafter, Pu is electrolytically reduced to trivalent in an electrolysis/valence adjustment step 4. FIG. 2 is a schematic sectional elevational view of an apparatus that can be employed for the electrolysis/valence adjustment step 4 of the first embodiment.
More specifically, a cathode chamber 27 and an anode chamber 28 are separated from each other by means of a diaphragm 50 in the apparatus. Catholyte 24 is stored in the cathode chamber 27 and a cathode 25 and a reference electrode 30 are dipped in the catholyte 24. Anolyte 51 is stored in the anode chamber 28 and an anode 26 is dipped in the anolyte 28. The cathode 25 and the anode 26 are connected to a power source 29. The cathode 25 and the reference electrode 30 are connected to a potentiometer 31.
The reference electrode 30 may typically be a silver/silver chloride electrode. The cathode chamber 27 is provided with an agitator 52 for agitating the catholyte 24.
With the above-described arrangement, Pu can be reduced to trivalent, while maintaining Np as pentavalent by limiting the cathode potential to not higher than -100 mV or confining the cathode current density within a range between not less than 20 mA/cm2 and 40 mA/cm2. The U that is partly reduced to tetravalent is employed to reduce Pu from tetravalent to trivalent.
Then, U itself is oxidized to become hexavalent.
FIG. 3 is a graph showing some of the results obtained by an experiment, which illustrates the correlation between the cathode potential and the current density observed in an electrolysis/valence adjustment step 4. It is experimentally proved that the cathode potential can be made equal to -0.1 V (-100 mV) by making the current density not less than about 20 mA/cm2.
Since the U is mostly hexavalent, only hexavalent U can be extracted into tributyl phosphate (TBP) -30% dodecane solution by using such a solution in a U extraction step 5. Trivalent ions of Pu and pentavalent ions of Np remain in the aqueous solution with the tetravalent ions of part of U. FIG. 4 is a graph showing some of the results of measurement of the change with time of the current density when the electrolysis potential is held to -1 00 mV relative to the reference electrode, which is a silver/silver salt electrode, in the electrolysis/valence adjustment step 4 and the U extraction step 5.
FIG. 4 shows that the cathode current density is within a range between 20 mA/cm2 and 40 mA/cm2 for the cathode potential of -100 mV.
Thereafter, oxalic acid is added to the aqueous solution that is left after the U extraction step 5 to produce oxalic acid precipitate 7 in an oxalic acid precipitation step 6. The oxalic acid precipitate 7 contains Pu and minor actinides such as Np, Am and Cm, some of rare earth elements (RE) and some of alkaline-earth metal elements. Of the fission products (FP), alkali metal elements and platinum group elements do not precipitate but are dissolved in the filtrate.
U, Pu, minor actinides and rare earth group elements are collected as oxalic acid precipitate 7 in the oxalic acid precipitation step 6.
In a chlorination step 8, hydrochloric acid is added to the oxalic acid precipitate 7 and dissolved at not higher than 100°C and subsequently hydrogen peroxide is added thereto in order to decompose the oxalic acid into water and carbon dioxide. The U, the Pu and the minor actinides in the oxalic acid precipitate 7 are converted into chloride 9 in this chlorination step 8.
Thereafter, the moisture in the hydrochloric acid solution is evaporated and removed in a dehydration step 40 and subsequently the moisture is completely eliminated at about 200°C in a flow of reductive inert gas (e.g., argon and nitrogen). As a result, chlorides (anhydrous chlorides) 41 of U, Pu and minor actinide are produced.
Then, U, Pu and metals. of minor actinides that can be used as fast reactor fuel can be collected in combination with each other as the produced anhydrous chlorides 41 are electrolyzed in a molten salt electrolysis step 10.
Now, a platinum group fission product collection step 14 of collecting platinum group fission products from the oxalic acid precipitate 7 obtained in the oxalic acid precipitation step 6 will be described below by referring to FIGS. 1 and 2. An apparatus having a structure same as the apparatus shown in FIG. 2 that is employed in the electrolysis/valence adjustment step and the U extraction step may be used in the platinum group fission product collection step 14. For example, the same apparatus may be used or another apparatus having the same structure or a similar structure may be used.
The oxalic acid precipitate 7 contains Pu and minor actinides such as Np, Am and Cm, some of rare earth elements and some of alkaline-earth metal elements. Of the fission products, alkali metal elements and platinum group elements are not precipitated by oxalic acid and are dissolved in the filtrate (catholyte) 24. The filtrate 24 that melts the fission products is put into the cathode chamber 27 and the insoluble cathode 25 is immersed in the filtrate 24 for electrolysis in the platinum group fission product collection step 14.
As a voltage is applied to the anode 26 and the cathode 25 from the power source 29, Pd(Palladium), Ru(Ruthenium), Rh(Rhodium), Mo and Tc(Technetium) that are platinum group fission products are deposited and collected out of the fission products contained in the filtrate 24 in the cathode chamber 27.
On the other hand, acidic anolyte 51 is put into the anode chamber 28. Since alkali metal elements such as Cs and alkaline-earth metal elements such as Sr that are contained in the filtrate, which is catholyte 24, remain in the filtrate, they can be separated from the platinum group fission products.
An applied voltage is observed by measuring the potential difference between the reference electrode 30 and the cathode 25 that are immersed in the cathode chamber 27 for the by means of the potentiometer 31. It is important to control the potentials so as to deposit Pd, Ru, Rh, Mo and Tc that are platinum group fission products without generating hydrogen.
Thus, the load of producing nuclear waste glass can be reduced because Pd, Ru, Rh, Mo and Tc that are platinum group -10 -fission products do not move into the high level liquid waste.
Additionally, the rate of producing high level liquid waste can also be reduced.
The hexavalent U that is extracted by TBP -30% dodecane in the U extraction step 5 is washed with nitric acid in a U purification step 11 and subsequently converted into an oxide in a denitration step 12 so as to be collected as high purity U02 13.
The high purity U02 13 can be used as oxide fuel for light water reactors.
[Second Embodiment] Now, the second embodiment of spent fuel reprocessing method according to the present invention will be described below by referring to FIGS. 5 and 6. The parts of this embodiment that same as or similar to those of the first embodiment are denoted respectively by the same reference symbols and will not be described repeatedly.
FIG. 5 is a flowchart of spent fuel reprocessing method according to a second embodiment of the present invention. FIG. 6 is a schematic sectional elevational view of an apparatus that can be employed for the electrolysis/reduction step of the second embodiment.
The sequence down to the oxalic acid precipitation step 6, where the oxalic acid precipitate 7 containing U, Pu, minor actinides and rare earth elements are collected, is same as that of the first embodiment.
This second embodiment has an oxidation/dehydration step -11 -and an electrolysis/reduction step 17 instead of the chlorination step 8, the dehydration step 40 and the molten salt electrolysis step of the first embodiment.
More specifically, the oxalic acid precipitate 7 collected in the oxalic acid precipitation step 6 is heated to remove moisture, while ozone or acidic gas is blown into it, in the oxidation/dehydration step 15 to produce oxides (precipitate oxides) 16 of U, Pu, minor actinides and rare earth elements.
Subsequently, moisture is completely removed from the oxides 16 while drawing oxygen by vacuum. Thereafter, as shown in FIG. 6, the oxides 16 are put into a stainless-steel-made cathode basket 19 and loaded in a molten salt electrolytic cell 22. The cathode basket 19 containing the oxides 16 of U, Pu, minor actinides and rare earth elements is connected to the cathode and an insoluble anode 20 typically made of platinum or grassy carbon is placed in position. As a voltage is applied to the cathode basket 19 and the anode 20 in a molten salt 21, oxygen ions are drawn out from the oxides of U, Pu and minor actinides in the cathode basket 19 to reduce them to make them become metals so that metals 18 of U, Pu and minor actinides can be collected.
The oxides 16.are put into the stainless-steel-made cathode basket 19 in a mixture of molten salts. The mixture of molten salts is preferably prepared by dissolving an oxide of an alkali metal or an alkaline-earth metal into a molten salt of chloride of an alkali metal or an alkaline-earth metal. More specifically, a mixture of molten salts is preferably prepared by dissolving Li20 into a molten -12 -salt of LiCI, dissolving MgO into a molten salt of MgCI2 or dissolving CaO into a molten salt of CaCI2.
After putting the oxides 16 into the cathode basket 19 in the mixture of molten salts, oxygen ions in the oxides 16 are drawn out and the drawn out oxygen ions are removed at the anode as oxygen gas or CO2 gas. Since alkali metal elements such as Cs, alkaline-earth metal elements such as Sr and rare earth elements such as Ce and Nd that are fission products are dissolved in the molten salts from the cathode basket 19 so that they can be separated from metals of U, Pu and minor actinide metals 18.
At this time, the oxides are reduced to become metals at the cathode in a manner as expressed by the formulas shown below.
U02 + 4e -+ U + 202 Pu02 + 4e -Pu + 202 On the other hand, oxygen gas is produced at the anode in a manner as expressed by the formula shown below.
202 -02 + 4e [Other Embodiment] The embodiments of the spent fuel reprocessing method in accordance with the present invention explained above are merely samples, and the present invention is not restricted thereto. It is, therefore, to be understood that, within the scope of the appended claims, the present invention can be practiced in a manner other than as specifically described herein.
-13 -

Claims (7)

  1. CLAIMS1. A spent fuel reprocessing method comprising: a disassembly/shear step of disassembling and shearing spent oxide nuclear fuel a dissolution step of dissolving the fuel subjected to the disassembly/shear step in nitric acid solution; an electrolysis/valence adjustment step of reducing plutonium to trivalent, maintaining the pentavalent of neptunium for the fuel subjected to the dissolution step; a uranium extraction step of collecting uranium oxide by bringing the fuel subjected to the electrolysis/valence adjustment step into contact with organic solvent and extracting hexavalent uranium by means of an extraction agent; an oxalic acid precipitation step of causing the minor actinides and the fissure products remaining in the nitric acid solution after the uranium extraction step to precipitate together as oxalic acid precipitate by means of an oxalic acid precipitation method; a chlorination step of converting the oxalic acid precipitate into chlorides by adding hydrochloric acid to the oxalic acid precipitate; a dehydration step of synthetically producing anhydrous chlorides by dehydrating the chlorides in a flow of reductive inert gas; and a molten salt electrolysis step of dissolving the anhydrous -14 -chlorides into molten salt and collecting uranium, plutonium and minor actinides at the cathode by electrolysis.
  2. 2. A spent fuel reprocessing method comprising: a disassembly/shear step of disassembling and shearing spent oxide nuclear fuel; a dissolution step of dissolving the fuel subjected to the disassembly/shear step in nitric acid solution; an electrolysis/valence adjustment step of reducing plutonium and neptunium respectively to trivalent and pentavalent for the fuel subjected to the dissolution step; a uranium extraction step of collecting uranium oxide by bringing the fuel subjected to the electrolysis/valence adjustment step into contact with organic solvent and extracting hexavalent uranium by means of an extraction agent; an oxalic acid precipitation step of causing the minor actinides and the fissure products remaining in the nitric acid solution after the uranium extraction step to precipitate together as oxalic acid precipitate by means of an oxalic acid precipitation method; an oxidation/dehydration step of dehydrating the oxalic acid precipitate and subsequently converting it into precipitate oxides in an oxidation atmosphere; and an electrolysis/reduction step of immersing the precipitate oxides in a mixture of molten salts obtained by dissolving alkali metal oxides in molten salts of chlorides of alkali metals or a -15 -mixture of molten salts obtained by dissolving alkaline-earth metal oxides in molten salts of chlorides of alkaline-earth metals, bringing the precipitate oxides into contact with a cathode to drawn out oxygen ions in the precipitate oxides, removing the oxygen ions as oxygen gas or carbon dioxide gas at the side of an anode in the molten salts and collecting uranium, plutonium and minor actinides in the precipitate oxides at the cathode.
  3. 3. The method according to claim 2, wherein the electrolysis/reduction step is conducted by containing the precipitate oxides in a stainless-steel-made cathode basket, immersing the cathode basket in the molten salts and connecting the cathode to the cathode basket.
  4. 4. The method according to claim 2 or 3, wherein the mixture of molten salts is a mixture of molten salts obtained by dissolving Li20 in molten salt of LiCI, a mixture of molten salts obtained by dissolving MgO in molten salt of MgCI2 or a mixture of molten salts obtained dissolving CaO in molten salt of CaCI2.
  5. 5. The method according to any one of claims I to 4, further comprising: a fission product collection step of putting the filtrate left without precipitating in the oxalic acid precipitation step into a cathode chamber, putting a cathode made of an insoluble material -16 -into the cathode chamber, putting acidic solution into an anode chamber separated from the cathode chamber by a diaphragm for electrolysis and depositing and collecting fission products of the platinum group remaining in the filtrate at the cathode.
  6. 6. The method according to any one of claims I to 5, wherein the electrolysis/valence adjustment step is conducted at or lower than -100 mV relative to a silver/silver chloride electrode operating as reference electrode.
  7. 7. The method according to any one of claims I to 6, wherein the electrolysis/valence adjustment step is conducted with a cathode current density between 20 mA/cm2 and 40 mA/cm2 relative to a silver/silver chloride electrode operating as reference electrode.-17 -
GB0909309A 2008-05-30 2009-05-29 Spent fuel reprocessing method Expired - Fee Related GB2461370B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2008143431A JP5193687B2 (en) 2008-05-30 2008-05-30 Spent fuel reprocessing method

Publications (3)

Publication Number Publication Date
GB0909309D0 GB0909309D0 (en) 2009-07-15
GB2461370A true GB2461370A (en) 2010-01-06
GB2461370B GB2461370B (en) 2010-10-20

Family

ID=40902333

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0909309A Expired - Fee Related GB2461370B (en) 2008-05-30 2009-05-29 Spent fuel reprocessing method

Country Status (6)

Country Link
US (1) US20090294299A1 (en)
JP (1) JP5193687B2 (en)
CN (1) CN101593566B (en)
FR (1) FR2931989A1 (en)
GB (1) GB2461370B (en)
RU (1) RU2403634C1 (en)

Families Citing this family (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2960690B1 (en) * 2010-05-27 2012-06-29 Commissariat Energie Atomique PROCESS FOR PROCESSING NUCLEAR FUELS USING NO PLUTONIUM REDUCING EXTRACTION OPERATION
FR2971948B1 (en) * 2011-02-28 2013-03-29 Commissariat Energie Atomique PROCESS FOR PRECIPITATION OF ONE OR MORE SOLUTES
JP5758209B2 (en) * 2011-06-14 2015-08-05 株式会社東芝 Spent fuel reprocessing method
CN102412002B (en) * 2011-09-06 2013-10-30 中国原子能科学研究院 N2O4Device for oxidation regulation of plutonium valence state
FR2980468B1 (en) * 2011-09-26 2014-01-24 Commissariat Energie Atomique PROCESS FOR THE PREPARATION OF AN OXYHALIDE AND / OR ACTINIDE OXIDE (S) AND / OR LANTHANIDE (S) FROM A MEDIUM COMPRISING AT LEAST ONE MELT SALT
JP5784476B2 (en) * 2011-12-09 2015-09-24 株式会社東芝 Uranium recovery method
JP5944237B2 (en) * 2012-06-15 2016-07-05 株式会社東芝 Method for recovering nuclear fuel material
FR2992330B1 (en) * 2012-06-26 2014-08-08 Commissariat Energie Atomique PROCESS FOR SEPARATING AT LEAST ONE FIRST E1 CHEMICAL ELEMENT OF AT LEAST ONE SECOND E2 CHEMICAL ELEMENT INVOLVING THE USE OF A MEDIUM COMPRISING A SPECIFIED MELT SALT
KR101316925B1 (en) * 2012-10-08 2013-10-18 한국수력원자력 주식회사 Treatment method of spent uranium catalyst
RU2561065C1 (en) * 2014-03-31 2015-08-20 Открытое акционерное общество "Радиевый институт имени В.Г. Хлопина" METHOD OF PRODUCING COMBINED SOLUTION OF U AND Pu
CN104008785B (en) * 2014-06-16 2016-08-17 中国工程物理研究院核物理与化学研究所 A kind of metal mold spentnuclear fuel after-treatment device
CN104143365B (en) * 2014-07-08 2017-02-01 中国核电工程有限公司 Neutron poison sandwich structure with openings in continuous dissolver
US9818496B2 (en) * 2014-08-18 2017-11-14 De Nora Permelec Ltd Method for treating tritium-water-containing raw water
CN104562089B (en) * 2014-10-17 2017-03-22 中国原子能科学研究院 Method for preparing initial molten salt system in molten salt electrolysis dry after-treatment process
GB2545934A (en) * 2016-01-02 2017-07-05 Richard Scott Ian Single stage reprocessing of spent nuclear fuel
CN108389641B (en) * 2017-12-28 2019-07-26 中国科学院近代物理研究所 A kind of preparation facilities and preparation method of nuclear fuel bead
CN109324070B (en) * 2018-08-08 2021-04-02 中国原子能科学研究院 Passive neutron analysis method for uranium plutonium content in waste cladding
JP7074615B2 (en) * 2018-08-27 2022-05-24 株式会社東芝 Neutron supply device and neutron supply method
CN109402413B (en) * 2018-10-30 2020-11-03 中国工程物理研究院核物理与化学研究所 Method for recovering palladium in fission product of spent fuel element
CN111188084B (en) * 2020-01-09 2021-04-02 中国原子能科学研究院 Replaceable integral electrode suitable for hot chamber application and electrode replacing device
GB2606640A (en) * 2020-10-14 2022-11-16 China Nuclear Power Technology Res Inst Co Ltd Dry aftertreatment method for spent fuel employing plasma
CN113684504B (en) * 2021-07-27 2022-12-09 西安交通大学 Electrolytic refining waste molten salt treatment method for spent fuel dry-process post-treatment
CN114752783B (en) * 2022-04-22 2023-10-03 厦门稀土材料研究所 High-efficiency Sr separation 2+ And Cs + Is a method of (2)
CN116665942B (en) * 2023-05-29 2024-01-23 西安交通大学 Spent fuel nuclide pre-separation method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2833800A (en) * 1947-12-19 1958-05-06 Donald F Mastick Process for purifying plutonium
US3361651A (en) * 1965-01-22 1968-01-02 Atomic Energy Authority Uk Electrolytic reduction of uranyl solutions
JPH07140293A (en) * 1993-11-16 1995-06-02 Toshiba Corp Recovery method of transuranic element from high level radioactive waste liquid
JPH0843584A (en) * 1994-07-26 1996-02-16 Toshiba Corp Method of turning oxalate of transuranium elements into chloride

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3276850A (en) * 1965-03-10 1966-10-04 Robert H Rainey Method of selectively reducing plutonium values
US2990240A (en) * 1952-08-11 1961-06-27 Charles V Ellison Process for segregating uranium from plutonium and fission-product contamination
US4131527A (en) * 1977-03-30 1978-12-26 The United States Of America As Represented By The United States Department Of Energy Method for selectively reducing plutonium values by a photochemical process
US4162230A (en) * 1977-12-28 1979-07-24 The United States Of America As Represented By The United States Department Of Energy Method for the recovery of actinide elements from nuclear reactor waste
US4278559A (en) * 1978-02-16 1981-07-14 Electric Power Research Institute Method for processing spent nuclear reactor fuel
DE3345199A1 (en) * 1983-12-14 1985-06-27 Kernforschungszentrum Karlsruhe Gmbh, 7500 Karlsruhe METHOD FOR REDUCTIVE PLUTONIUM RETURN EXTRACTION FROM AN ORGANIC REPROCESSING SOLUTION IN AN AQUEOUS, Nitric Acid Solution Using an Electrolysis Stream
CN1037914C (en) * 1993-03-04 1998-04-01 清华大学 Method for separating actinide elements from concentrated high-radioactive waste liquid
JP2726375B2 (en) * 1993-08-13 1998-03-11 動力炉・核燃料開発事業団 Method for separating and recovering Pu and Np from nitric acid solution containing Pu and Np
JP2948166B2 (en) * 1997-04-04 1999-09-13 核燃料サイクル開発機構 Recovery method of transuranium element from spent nuclear fuel
JPH1184073A (en) * 1997-09-11 1999-03-26 Hitachi Ltd Method and device for reprocessing spent nuclear fuel
FR2803283B1 (en) * 2000-01-03 2002-03-29 Cogema PROCESS AND DEVICE FOR THE CONTINUOUS CONVERSION OF PLUTONIUM OXALATE TO PLUTONIUM OXIDE
JP3549865B2 (en) * 2001-11-28 2004-08-04 核燃料サイクル開発機構 Separation and recovery method of rare element FP in spent nuclear fuel and nuclear power generation-fuel cell power generation symbiosis system using the same
WO2006027612A2 (en) * 2004-09-09 2006-03-16 Cambridge Enterprise Limited Improved electro-deoxidation method, apparatus and product
FR2880180B1 (en) * 2004-12-29 2007-03-02 Cogema IMPROVEMENT OF THE PUREX PROCESS AND ITS USES
FR2901627B1 (en) * 2006-05-24 2009-05-01 Commissariat Energie Atomique PROCESS FOR THE REHABILITATION OF USEFUL NUCLEAR FUEL AND THE PREPARATION OF A MIXED OXIDE OF URANIUM AND PLUTONIUM
WO2008105928A2 (en) * 2006-09-08 2008-09-04 Michael Ernest Johnson Process for treating compositions containing uranium and plutonium
JP4928917B2 (en) * 2006-11-27 2012-05-09 株式会社東芝 Spent oxide nuclear fuel reduction device and lithium regenerative electrolysis device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2833800A (en) * 1947-12-19 1958-05-06 Donald F Mastick Process for purifying plutonium
US3361651A (en) * 1965-01-22 1968-01-02 Atomic Energy Authority Uk Electrolytic reduction of uranyl solutions
JPH07140293A (en) * 1993-11-16 1995-06-02 Toshiba Corp Recovery method of transuranic element from high level radioactive waste liquid
JPH0843584A (en) * 1994-07-26 1996-02-16 Toshiba Corp Method of turning oxalate of transuranium elements into chloride

Also Published As

Publication number Publication date
CN101593566B (en) 2012-08-29
CN101593566A (en) 2009-12-02
RU2403634C1 (en) 2010-11-10
FR2931989A1 (en) 2009-12-04
GB2461370B (en) 2010-10-20
US20090294299A1 (en) 2009-12-03
JP2009288178A (en) 2009-12-10
JP5193687B2 (en) 2013-05-08
GB0909309D0 (en) 2009-07-15

Similar Documents

Publication Publication Date Title
US20090294299A1 (en) Spent fuel reprocessing method
US7749469B2 (en) Process for recovering isolated uranium from spent nuclear fuel using a highly alkaline carbonate solution
Malmbeck et al. Advanced fuel cycle options
JP4049324B2 (en) Real-time measurement method of uranium oxide reduction process with metallic lithium
Swain et al. Separation and recovery of ruthenium from nitric acid medium by electro-oxidation
EP1240647B1 (en) Actinide production
Kim et al. In situ analysis for spontaneous reduction of Eu 3+ in LiCl pyroprocessing media at 923 K
JP2002055196A (en) Method for disposal of radioactive waste
Hur et al. Chemical behavior of fission products in the pyrochemical process
Palamalai et al. Development of an electro-oxidative dissolution technique for fast reactor carbide fuels
JP5758209B2 (en) Spent fuel reprocessing method
JP4679070B2 (en) Method for reprocessing spent oxide fuel
JP3519557B2 (en) Reprocessing of spent fuel
JP2997266B1 (en) Method for separating and recovering platinum group elements, technetium, tellurium and selenium
JPWO2004036595A1 (en) Light water reactor spent fuel reprocessing method and apparatus
RU2499306C1 (en) Method of cleaning irradiated nuclear fuel
Park et al. Behavior of diffusing elements from an integrated cathode of an electrochemical reduction process
RU2493295C1 (en) Method for electrochemical deposition of actinides
JP6515369B1 (en) Insoluble residue treatment process
JP3030372B2 (en) How to separate fission-generated noble metals
WO2011144937A1 (en) Novel reprocessing method
JPH07140293A (en) Recovery method of transuranic element from high level radioactive waste liquid
US2834722A (en) Electrochemical decontamination and recovery of uranium values
González Voltammetric Analysis of Moisture-Induced Impurities in LiCl-Li2O Used for Direct Electrolytic Reduction of UO2 and Demonstration of Purification Process
CN118222857A (en) Method for efficiently separating actinides and lanthanoids

Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20220529