CA2248870A1 - Separation of isotopes by ionisation for processing of nuclear fuel materials - Google Patents
Separation of isotopes by ionisation for processing of nuclear fuel materials Download PDFInfo
- Publication number
- CA2248870A1 CA2248870A1 CA 2248870 CA2248870A CA2248870A1 CA 2248870 A1 CA2248870 A1 CA 2248870A1 CA 2248870 CA2248870 CA 2248870 CA 2248870 A CA2248870 A CA 2248870A CA 2248870 A1 CA2248870 A1 CA 2248870A1
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- Prior art keywords
- ionised
- feed
- components
- plasma
- process according
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- 239000000463 material Substances 0.000 title claims abstract description 93
- 238000012545 processing Methods 0.000 title claims abstract description 33
- 238000000926 separation method Methods 0.000 title claims abstract description 31
- 239000003758 nuclear fuel Substances 0.000 title description 7
- 238000000034 method Methods 0.000 claims abstract description 82
- 230000008569 process Effects 0.000 claims abstract description 64
- 239000000126 substance Substances 0.000 claims abstract description 42
- 239000007788 liquid Substances 0.000 claims abstract description 16
- 239000007787 solid Substances 0.000 claims abstract description 16
- 230000005291 magnetic effect Effects 0.000 claims description 45
- 239000000047 product Substances 0.000 claims description 40
- 150000002500 ions Chemical class 0.000 claims description 27
- 229910052751 metal Inorganic materials 0.000 claims description 25
- 239000000446 fuel Substances 0.000 claims description 19
- 239000002184 metal Substances 0.000 claims description 19
- 239000000203 mixture Substances 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 9
- 238000010791 quenching Methods 0.000 claims description 7
- 238000001816 cooling Methods 0.000 claims description 6
- 230000003116 impacting effect Effects 0.000 claims description 5
- 230000000171 quenching effect Effects 0.000 claims description 5
- 239000012265 solid product Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000008188 pellet Substances 0.000 claims description 4
- 230000009471 action Effects 0.000 claims description 2
- 238000009835 boiling Methods 0.000 claims description 2
- 238000001704 evaporation Methods 0.000 claims description 2
- 230000008020 evaporation Effects 0.000 claims description 2
- 230000003993 interaction Effects 0.000 claims description 2
- 229910052755 nonmetal Inorganic materials 0.000 claims description 2
- 238000000859 sublimation Methods 0.000 claims description 2
- 230000008022 sublimation Effects 0.000 claims description 2
- 230000007704 transition Effects 0.000 abstract description 6
- 229910052770 Uranium Inorganic materials 0.000 description 50
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 description 41
- 229910052731 fluorine Inorganic materials 0.000 description 24
- 239000011737 fluorine Substances 0.000 description 24
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 23
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 16
- 239000007789 gas Substances 0.000 description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 13
- 150000001875 compounds Chemical class 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 13
- SANRKQGLYCLAFE-UHFFFAOYSA-H uranium hexafluoride Chemical compound F[U](F)(F)(F)(F)F SANRKQGLYCLAFE-UHFFFAOYSA-H 0.000 description 13
- 229910052757 nitrogen Inorganic materials 0.000 description 12
- 229910052760 oxygen Inorganic materials 0.000 description 12
- 239000001301 oxygen Substances 0.000 description 12
- VEMKTZHHVJILDY-PMACEKPBSA-N (5-benzylfuran-3-yl)methyl (1r,3s)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropane-1-carboxylate Chemical compound CC1(C)[C@@H](C=C(C)C)[C@H]1C(=O)OCC1=COC(CC=2C=CC=CC=2)=C1 VEMKTZHHVJILDY-PMACEKPBSA-N 0.000 description 11
- 229940077390 uranyl nitrate hexahydrate Drugs 0.000 description 11
- -1 piutonium Chemical compound 0.000 description 10
- 125000004429 atom Chemical group 0.000 description 10
- 229910052739 hydrogen Inorganic materials 0.000 description 8
- 239000000919 ceramic Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 229910052778 Plutonium Inorganic materials 0.000 description 5
- 230000004992 fission Effects 0.000 description 5
- OYEHPCDNVJXUIW-UHFFFAOYSA-N plutonium atom Chemical compound [Pu] OYEHPCDNVJXUIW-UHFFFAOYSA-N 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 4
- WZECUPJJEIXUKY-UHFFFAOYSA-N [O-2].[O-2].[O-2].[U+6] Chemical class [O-2].[O-2].[O-2].[U+6] WZECUPJJEIXUKY-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 150000004820 halides Chemical group 0.000 description 4
- 239000011261 inert gas Substances 0.000 description 4
- 238000010587 phase diagram Methods 0.000 description 4
- 238000004064 recycling Methods 0.000 description 4
- 239000002915 spent fuel radioactive waste Substances 0.000 description 4
- 239000010936 titanium Substances 0.000 description 4
- 229910052719 titanium Inorganic materials 0.000 description 4
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 4
- ZSLUVFAKFWKJRC-IGMARMGPSA-N 232Th Chemical compound [232Th] ZSLUVFAKFWKJRC-IGMARMGPSA-N 0.000 description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910052776 Thorium Inorganic materials 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 3
- 229910052801 chlorine Inorganic materials 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910052688 Gadolinium Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000003682 fluorination reaction Methods 0.000 description 2
- 125000001153 fluoro group Chemical group F* 0.000 description 2
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 238000010943 off-gassing Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 238000009877 rendering Methods 0.000 description 2
- 229910000439 uranium oxide Inorganic materials 0.000 description 2
- MZFRHHGRNOIMLW-UHFFFAOYSA-J uranium(4+);tetrafluoride Chemical compound F[U](F)(F)F MZFRHHGRNOIMLW-UHFFFAOYSA-J 0.000 description 2
- 229910002007 uranyl nitrate Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 102000004405 Collectins Human genes 0.000 description 1
- 108090000909 Collectins Proteins 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- HOKDBMAJZXIPGC-UHFFFAOYSA-N Mequitazine Chemical compound C12=CC=CC=C2SC2=CC=CC=C2N1CC1C(CC2)CCN2C1 HOKDBMAJZXIPGC-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- MVXWAZXVYXTENN-UHFFFAOYSA-N azanylidyneuranium Chemical compound [U]#N MVXWAZXVYXTENN-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000002801 charged material Substances 0.000 description 1
- 239000013626 chemical specie Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 150000002221 fluorine Chemical class 0.000 description 1
- 150000002222 fluorine compounds Chemical class 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000000752 ionisation method Methods 0.000 description 1
- 230000005923 long-lasting effect Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910001507 metal halide Inorganic materials 0.000 description 1
- 150000005309 metal halides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000010955 niobium Substances 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 238000006396 nitration reaction Methods 0.000 description 1
- ZQPKENGPMDNVKK-UHFFFAOYSA-N nitric acid;plutonium Chemical compound [Pu].O[N+]([O-])=O ZQPKENGPMDNVKK-UHFFFAOYSA-N 0.000 description 1
- OOAWCECZEHPMBX-UHFFFAOYSA-N oxygen(2-);uranium(4+) Chemical compound [O-2].[O-2].[U+4] OOAWCECZEHPMBX-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 230000027756 respiratory electron transport chain Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- VGBPIHVLVSGJGR-UHFFFAOYSA-N thorium(4+);tetranitrate Chemical compound [Th+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VGBPIHVLVSGJGR-UHFFFAOYSA-N 0.000 description 1
- FCTBKIHDJGHPPO-UHFFFAOYSA-N uranium dioxide Inorganic materials O=[U]=O FCTBKIHDJGHPPO-UHFFFAOYSA-N 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C19/00—Arrangements 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
- G21C19/42—Reprocessing of irradiated fuel
- G21C19/44—Reprocessing of irradiated fuel of irradiated solid fuel
- G21C19/48—Non-aqueous processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D59/00—Separation of different isotopes of the same chemical element
- B01D59/44—Separation by mass spectrography
- B01D59/48—Separation by mass spectrography using electrostatic and magnetic fields
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D59/00—Separation of different isotopes of the same chemical element
- B01D59/50—Separation involving two or more processes covered by different groups selected from groups B01D59/02, B01D59/10, B01D59/20, B01D59/22, B01D59/28, B01D59/34, B01D59/36, B01D59/38, B01D59/44
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
Abstract
Improved processing apparatus and methods are provided which involve the selective ionisation of a feed material and the separation of ionised and non-ionised species. Introduction of a chemical material to cause selective transition to a non-ionised and/or solid or liquid state of part of the feed is provided. The process offers high through puts by virtue of the ionised and non-ionised species being in equilibrium with one another.
Description
wo 97/34684 PCT/GB97/00671 SEPARATION OF ISOTOPES BY IONISATION FOR PROCESSING OF NUCLEAR
FUEL MATERIALS
This invention concerns improvements in and relating to processing, particularly, but not exclusively to the processing of nuclear fuel materials and materials involved in the nuclear fuel indùstry.
The production and recycling of fuel grade nuclear fuel and associated materials involve long and complex processes.
For instance, starting from mined uranium ore, in general terms the process involves taking the ex-mine grade material and gradually converting and enriching it until it is in a form and of a grade suitable for producing fuel pellets.
In~ermediate stages in the overall process route form the starting point for the production of a variety of other materials too.
The basic stages in the overall process are the concentration of the initial uranium oxides as uranyl nitrate hexahydrate; a de-nitration stage to convert the material into UO3; a reduction stage to convert the UO~ to UO~; a hydro-fluorinatlon stage to form UFJ; a further fluorination stage to produce UF~; an enrichment procedure by physical or chemical means; and the conversion of UFh in its enriched form to ceramic grade UO~ which is in a suitable form to be formed into fuel pellets.
Recycling of spent fuel similarly involves a series of complex chemical and physical steps to separate the various fission products from the depleted fuel and to upgrade the 235U
concentration in the material to a stage where once a~ain it can be employed as fuel by separating out other components present in the used fuel.
The complexities of these processes are also present in other production processing lines involved in or relating to fuel cycles, such as thorium, plutonium and gadolinium amonqst other materials. The production of uranium metal, non-enriched, for instance for use in Magnox reactors, also involves complex processing.
.. .. .
Extensive or involved processing is also encountered in the production of other materials outside the immediate nuclear fuel field. for example, the commonly employed production route for titanium, niobium and rhodium metal, amongst others, involves the rendering of the metal containing compounds into an halide form followed by its decomposition from the halide form to the metal.
Substantial processing plants, in terms of their size, capital investment and running costs, are necessary to perform the stages involved in all of these processes. Attendant problems also follow from the various processes and their requirements. For instance, processes involving fluorination involve a complex and hazardous electrolysis process to produce the fluorine required.
The present invention aims to provide an alternative processing route for many processes and/or a process for rendering materials into more useful forms and/or a process for recycling materials, together with apparatus for achieving the processes.
According to a first aspect of the invention we provide a process comprising the steps of:-a) providing a feed, the feed consisting of mixed components;
b) converting said feed into a plasma or ionised form;
c) providing at least one component in at least partially ionised form and at least one different component in at least partially non-ionised form;
d) containing said plasma / ions in 2 magnetic field; and e) separating said ionised components fro~
said non-ionised components.
The component desired may be extracted from a mlxture OL-isotopes and/or elements of both metal and non-metal nature.
The separation may be complete or partial.
The provision of the ~eed in a nitrogen containlng compound is envisaged, but provision of the feed in a fluorine containing form is particularly preferred. Feed material consisting of uranyl nitrate, uranium hexafluoride, plutonium nitrate, thorium nitrate, depleted uranyl nitrate, depleted uranium hexafluoride or mixtures thereof all represent suitable feed materials. Other suitable feed materials include spent nuclear fuel, uranium tetrafluoride and other metals in halide forms, such as titanium tetrachloride. These materials may be in hydrated form.
The mixed components may consist of two or more different elements; two or more different isotopes of the same element;
different elements together with different isotopes of one or more of those elements; or compounds and/or mixtures of compound~ incorporating different elements, different isotopes or different isotopes and different elements, and reference in this application to the term components should be taken to include all such possibilities, amongst others, unless stated to the contrary.
The feed may be introduced to the magnetic field as a gas, liquid, solid or mixture of states. A gas feed to the magnetic field is preferred.
The feed may be introduced to the plasma generation means as a gas, liquid, solid or mixture of states.
The feed may be introduced to the ionisation means as a gas, liquid, solid or mixture of states. A gas feed to the ionisation means is preferred, particularly where a plasma generator is not also provided.
The feed may be provided in gaseous form by boiling and/or evaporation and/or sublimation of a solid or liquid initial feed. The conversion to gaseous state may be effected by a furnace, microwave heater or other form of heater means.
Preferably the gas is introduced prior to ionisation Preferably all, or substantially all, of a given component is ionised. Preferably all, or substantially all, of a given component is not ionised.
Preferably some or all metallic elements present in said feed are ionised. The ionisation of metallic elements with an atomic-weight greater than 90 is particularly preferred.
Preferably some or all non-metallic elements in said feed are not ionised. Preferably all elements with an atomic weight below 90, most preferably below 70 and ideally below ~0, are left in non-ionised form. It is particularly preferred that elements such as uranium and/or plutonium and/or thorium and/or gadolinium are ionised. It is preferred that elements such as hydrogen and/or fluorine and/or oxygen and/or nitrogen are not ionised. Preferably boron is not ionised. Preferably fission products are not ionised.
The ionisation of the components may be caused by the temperature of the plasma. Additionally or alternatively the ionisation of the components may be caused by the interaction of the components with high energy electrons produced by electron cyclotron resonance.
The extent of ionisation and/or components ionised may be controlled by the energy input of and/or residence time in the electron cyclotron resonance unit.
Prefera~ly the ionisation is controlled by the level of energy input. The level of energy input may be controlled by controlling the temperature of the plasma. Preferably the energy input is not selective between components of the feed.
In this way all of the components of the feed are preferably raised to the same energy level. Preferably the ionised and non-ionised feed components are in equilibrium with one another for the prevailing conditions.
The feed material may be converted to a gas and fed to an ECR unit for ionisation. A furnace heater or evaporator may be used to convert the solid or liquid feed to gaseous / vapour form.
In a particular embodiment, therefore, the plasma may convert the feed materials to discrete atoms and electron cyclotron resonance may subsequently 9ive rise to at least partial ionisation, preferably of a selective nature.
The feed may be provided in molecular form and be converted to discrete atoms and/or elemental forms by the plasma generation and/or ionisation means and/or heating means.
The conversion to discrete atoms and/or elemental forms may give rise to partial ionisation of one or more of the resulting species. Thus a uranyl nitrate hexahydrate feed may be converted to U, N and H (discrete atomic forms), together with N2 and 02 (elemental forms), as well as U+ (ionised species).
Preferably the feed is provided in molecular form and selectively separated as discrète atoms and/or elemental forms from ionised discrete atomic forms and/or elemental forms.
This renders the technique applicable to a wider variety of materials than are possible with elemental feed and separation in elemental form or molecular feed followed by separation in molecular form.
The temperature of said plasma may be controlled to provide selective ionisation of the components in the desired way. Thus the plas~a may ionise some components in the feed but leave other components, such as fission products and/or non-metallic elements, un-ionised.
Preferably said plasma is provided at 3000 to 4500K.
Preferably said plasma is generated by microwave or radio frequency means. Preferably the plasma in the generator is operated at between 1000 and 10000 Pa. A value of 2000 +/- 10%
is preferred.
Additionally or alternatively the residence time of the feed within the plasma prior to the separation may be controlled to provide selective ionisation of the components in the desired way.
Preferably the feed is introduced into the containing magn ic field in un-ionised form. Preferably the partial ionisation process occurs within the magnetic field on an uncharged gas. The gas may be in molecular and/or atomic form.
The magnetic field may be configured to define cylindrical active ;volume in which the plasma/ions are processed. Preferabiy the plasma/ions pass along the axis of .. .. . . ..
this containment area from the plasma generation and/or ionisation means to the next, separation, stage.
Preferably the separation of ionised and un-ionised components is affected by removing the un-ionised component from the plasma, most preferably as a gas. The un-ionised components may be pumped away from the ionised component. The ionised component is contained and hence restrained by the magnetic field.
The separation of ionised from non-ionised components may be effected in a number of stàges. Preferably the stages are discrete from one another. The stages maybe separated from one another by a baffle provided with an aperture. Preferably the aperture is entirely within the containment area of the magnetic field. Preferably one or more of the stages are operated at different pressures to one or more other stages.
The pressure level may be maintained by the pumping level employed. Preferably the pressure in one or more stages near to the inlet is higher than one or more further away from the inlet. Preferably the pressure decreases for each zone relative to the preceding stage nearer the inlet. Preferably the pressure in each stage is 30% to 60% of that in the preceding stage, progressing away from the inlet.
Preferably three stages are provided. Each stage may be between 0.5 and 2m in length.
Preferably the first stage is operated at between 10 and 50 Pa. A level of 40 Pa +/- 10% is preferred.
Preferably the second stage is operated at between 5 and 20 Pa. A level of 16 Pa +/- 10% is preferred.
Preferably the third stage is operated at between 2 and 10 Pa. A level of 7 Pa +/- 10% is preferred.
The separated un-charged components may be recycled for subsequent use and/or subjected to further processing. ~his may include further selective ionisation and / or selective processing to separate different components.
The separated charged components are preferably still contained in a ~agnetic field. The separated charged components may be subjected to further processing including selective de-ionising; de-ionising followed by further selective ionisation; or other selective processing to separate differe-nt components.
The charged components may be cooled, and/or discharged to provide a liquid and/or solid uncharged product. The charged components may be collected on an earthed or charged grid, plate, electrode or mass of the product itself. The charged components may be collected in a vessel or container.
A reservoir of liquid may be provided in the vessel or container.
The temperature conditions may be controlled to purify the collected components by vaporising off impurities. The impurities may be vaporised in the form of compounds with the metal and / or collected component. Vaporisation of halides is envisaged.
The collected charged components may be periodically or continuously removed from the collection point.
The method may comprise the further step of introducing a chemical material, preferably at a controlled ~inetic energy level, and contacting this with the remaining charged component(s), the kinetic energy level of the charged component and chemical material being such that an un-charged component or particle results. The component may still be present as a gas.
The chemical material may consist of a material selected to give the desired uncharged particle and / or end product, such as oxygen or an inert gas as the chemical material. The chemical material may be added at a temperature of between lOOK
and 2000K and particularly lOoK to 500K. The component and chemical material may be combined in the resulting particle.
An oxide represents a potential form.
The temperature of the combined form may be controlled so as to provide the particle in the desired form. A temperature of 2500K is preferred with uranium so as to present the uranium as gaseous UO? as the principle torm.
A step may be provided in which a further chemical material is added to the un-char~ed component so as to reduce the kinetic energy level to a stage where a solid product is produced. Alternatively or additionally the kinetic energy level -reduction can be provided by impacting the uncharged component on a surface, preferably a cooled surface. The kinetic energy level reduction for the un-charged particle may occur very rapidly so as to avoid undesired intermediate equilibrium forms of the product. A transition period of <2 ms is preferred.
The further chemical material may be the same or different from the chemical material previously added.
Preferably the product of the process is the desired compound, element or isotope and preferably at the desired grade. Ceramic grade metal oxide is a particularly preferred product of the process although pure metal can also be produced in this way. Uranium, piutonium, thorium and indeed MOX
products can be produced by controlling the process conditions.
According to a second aspect of the invention we provide separation apparatus, said apparatus comprising:
a) a plasma / ion generator;
b) means for selectively ionising a feed material of mixed components;
c) magnetic field generating means producing a magnetic field for containing the plasma / ions; and d) means to remove un-charged components from the magnetic field.
The feed may be provided as a solid, liquid or gas.
A furnace, heater, microwave source, evaporator or other heating means may be used to heat and/or vaporise and/or sublime and/or gasify and/or evaporate the feed.
Preferably the plasma/ions are generated by microwave or radio frequency heating. The ionisation of the components may be caused by the temperature of the plasma.
Preferably the plasma is heated to between 3000 and 4500K
and most preferably 4000K + or - 10%. Preferably the outlet from the plasma / ion generator is between 20 and 40 mm in radius.
The plasma generator may act as the means for selectively ionising the feed material mixed components. Alternatively or additionally high energy electron collisions produced by electron cyclotron resonance means may provide the means for selectively ionising the feed material of mixed components.
The feed may be fed to the ECR as a molecular and/or atomic gas.
Preferably the extent of ionisation and/or components ionised are controlled by the level cf energy input. The energy level may be controlléd by the temperature. Preferably the feed is excited evenly. Preferably t.he energy input is not selective between components present. Preferably the partial ionisation/partial non-ionisation of the feed resulting is at equilibrium for the prevailiny conditions.
The containing magnetic field may be axially aligned.
Preferably the magnetic field generating means comprises one or more solenoids. Preferably the magnets are provided in an annular or cylindrical assembly. In this way a central containment area is defined by the magnetic field, preferably of cylindrical configuration. Preferably the magnetic field is provided as a containment field most preferably in an axial alignment. Field strengths in excess of 0.075 tesla or in excess of 0.1 tesla may be used for this purpose.
Preferably the feed is introduced to the magnetic field before ionisation.
Preferably the separation is affected by removing the un-ionised component from the plasma. Preferably the means for removing un-charged components comprise a pump unit.
Preferabl~ the charged components are retained in the magnetic field.
The un-ionised components may be separated from the feed in one or more stages. Preferably one or more outlets through which the un-ionised components are withdrawn are provided in each stage.
Preferably the;sta~es are separated from one another by a baffle element. Preferably the baffle is provided with a circular aperture throu~h ~hich the feed passes. Preferably .. , . , . , . ., .. ~ .
the apertures in the baffles are axially aligned. The diameter or size of the aperture in one or more baffles may be greater than the aperture in one or more baffles nearer the feed inlet than said aperture. Preferably the apertures increase in diameter sequentially away from the feed inlet.
Preferably the aperture has a radius substantially corresponding to the plasma / ion stream radius at that distance from the inlet. Preferably the apertu~e radius is the same or less than 10% larger than the plasma / ion stream radius at that location. Preferably the radius of one or more of the apertures is approximately proportional to the fourth root of the distance from the inlet or plasma generator nozzle.
Preferably the aperture radius is less than the radius of the containment area defined by the magnetic field at that location.
The apparatus may further provide addition means for a chemical material to the remaining process stream. Preferably the chemical material introduced is oxygen or an inert gas. It is particularly preferred that the chemical material added provides a quenching and/or cooling action to the remaining components. Preferably the chemical material on contacting the remaining components converts it from a charged to an un-charged phase. Most preferably the component is $till retained in the gaseous state following this change.
In a particularly preferred embodiment the addition of oxygen is employed as the chemical material. Preferably this is introduced at lO0 to 5001~ to give an approximate combined temperature of 2500K in combination with the charged component.
At this temperature for instance, U is retained as an un-charged gas primarily in the form U0,.
A still further means for addition of a further chemical material may be provided. Preferably this further addition converts the process stream fronl a gaseous to solid state.
Alternatively or additionally the kinetic energy level reduction can be provided by impacting the uncharged component on a surface, preferably a cooled surface. The conversio" is preferably obtained very rapidly indeed so as to restrict any intervening equilibrium states forming. Preferably the product is a ceramic grade fuel material, such as UO?.
According to a third aspect of the invention we provide a process comprising the steps of:-a) providing a feed, the feed consisting of mixed components;
b) converting said feed into a plasma/ionised form;
c) providing at least one component in at least partially ionised form and at least one component in at least partially non-ionised form;
d) containing said plasma/ions in a magnetic field; and e) separating said ionised components from said non-ionised components; and further comprising converting at least some of the separated ionised component or components to an un-charged form.
The component may be converted to uncharged form by reducing its kinetic energy level, i.e. to condense it.
The component may be converted to uncharged form by impacting it on a surface, preferably a cooled surface.
The component may be converted to uncharged form by addition of a chemical material. A combination of one or more of these may be used.
Preferably the chemical material is added at a predetermined kinetic energy level so as to give the desired un-charged form. Most preferably the un-charqed form is in a gaseous form. Conversion of one, or a portion of one or more components to the un-charged form, whilst retaining one or more other components, or a portion of one or more other components and/or a portion of the first component or components in charged form is envisaged.
The addition of the chemical material, or the addltion of further chemical material in a further stage, may be such so as to reduce the kinetic energy level to a stage where a solid product is produced.
_ The chemical material added may react with the component or may simply reduce its kinetic energy level. The component may be produced in elemental or compound form.
Preferably the transition from un-charged gaseous particle to solid product occurs very rapidly. A transition period of less than 2 ms is preferred.
The separation of uranium and fluorine from a uranium hexafluoride feed is one potential use. Additionally the separation of uranium from uranyl nitrate hexahydrate and other feed forms is envisaged.
The further processing and subsequent use of the un-charged components separated from the charged components is envisaged. The production or recycling of fluorine using this route is a particularly preferred form.
This aspect of the invention may of course include any of the features or possibilities discussed elsewhere in this application, including those relating to the ion/plasma generation, its containment, the manner of the separation and others.
According to a fourth aspect of the invention we provide separation apparatus said apparatus comprising:-a) a plas~.a / ion generator;
b) means for selectively ionising the feed material of mixed components;
c) magnetic field generating means producing a containing magnetic field- for the plasma / ions;
d) means for removing un-charged components from the magnetic field; and e) means for converting at least some of the separated charged components to unchar~ed form.
The component may be converted to uncharged form by reducing its ~inetic energy levei, i.e. to condense it.
The component may be converted to uncharged form by impacting it on a surface, preferably a cooled surface.
The component may be converted to uncharged form by addition of a chemical material. ~ combination of one or more of these may be used.
The chemical material may he introduced in a single or in multiple stages. Where multiple stages are used it is preferred that the various inlets oe spaced from one another along the direction of the process stream travel. Thus first means may be provided to effect a transition from a charged to un-charged state and second or further stages may be provided to convert the un-charged component to the solid state or to the desired chemical composition. The production of both elemental and compound forms of the desired product is envisaged.
of course other feat~res of the apparatus or methods discussed elsewhere in this application can be equally relevant to this aspect.
According to a fifth aspect of the invention we provide components, materials, compounds, elements, or isotopes separated according to the first and/or third aspects of the invention and / or using the apparatus of the second and/or fourth aspects of the invention and/or further processed forms thereof.
The separated components may be different elements presented in the feed. Thus the separation of uranium from fluorine is envisaged, as is the separation of other elements present in one or more given compounds from each other. The production of ceramic grade metal oxides suitable for fuel use is envisaged.
The degree of separation between the components may be substantially complete or only partial. Thus processes in which a proportion of the component in the feed is extracted as un-charged components ir, the process whilst the majority of that component continues into the product stream produced from the charged components is envisayed.
of course the un-charyed first or second product stream may constitute the useful and aimed for separated component as much as the final end product from the charqed component.
, W O 97/34684 PC~/GB97/00671 According to an sixth aspect of the invention we provide a fuel pellet, fuel rod or fuel assembly or part for a nuclear reactor- incorporating the product, or a further processed product, of any of the first to fifth aspects of the invention.
Various embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings in which:-Figure 1 illustrates schematically a firstembodiment of the invention;
Figure 2 illuslrates a phase diagram for uranium, oxygen, nitrogen and hydrogen;
Figure 3 is a phase diagram for U+, UO, UO, and UO~;
Figure 4 schematically illustrates a partial view of a second embodiment of the invention;
Figure 5 schematically illustrates a third embodiment of the invention; and Figure 6 schematically illustrates a fourth embodiment of the invention.
The techniques of the present invention offer versatile processing systems which can be successfully employed with a variety of starting materials and states and produce a variety of product materials, states and forms.
Uranyl nitrate hexahydrate feed As illustrated in Figure 1 the feed to be processed is introduced according to arrow 2. In this particular example the feed material consists of a uranyl nitrate hexahydrate feed liquor. The feed liquor passes through a plasma yenerator (4) which rapidly heats the feed liquor to around 4000K. The plasma generator (4) may be a microwave or RF type plasma generator. Control of the plasma temperature can readily be provided.
Conducting solenoids in array (G) produce a high intensity magnetic field whose lines of force are schematically represented (8). By the stage at ~hich the feed is ionised within the plasma generator it is already within the confines of this magnetic field.
~ he conducting solenoids are se~ to produce a field intensity in excess of 0.1 tesla.
As a consequence of the plasma generator (4) the feed material enters chamber (12) at a highly elevated temperature.
At this temperature the uranyl nitrate hexahydrate breaks down into its component atoms. This allows processing of the feed material according to its individual atomic make up rather than needing an elemental feed or processing the feed only according to differences between the molecules which are either subsequently ionised or not.
As can be seen from the phase diagram provided in Figure 2 at 4000K and under the type of conditions experienced in chamber (12) uranium atoms are charged, U+, line 20.
Conversely at this temperature the bulk of the nitrogen, oxygen, and hydrogen are un-charged atoms or molecules as seen by the lines of Figure 2 which represent the nitrogen, N, line 22; oxygen, 0, line ?4; and hydrogen, H, line 26; ions all in gaseous form.
The selective ionisation occurs as a result of the overall energy level of the system. Thus the species which are ionised under the prevailing conditions and the species which are not, are determined by the equilibrium state for that species under those conditions. The selective ionisation obtained is, therefore, stable and long lasting allowing the subsequent processing to be carried out witnout pressure of time.
If energy is only selectively inputted to certain species within the system then selective ionisation can be obtained.
However, collisions between ionised and non-ionised species in such a case result in energy trans~er which can result in the ionisation of the previously non-ionised species and/or the discharge of the previously ionised species. In such a case separation must be performed very rapidly or the selective nature will decay prior tc any significant selectivity being obtained in the separation.
In the equilibrium state plasma of the present system collisions are not only tolerable they are desirable to ensure even distribution of the energy input throughout the plasma.
Collisions, however, have no detrimental effect as, for example, a collision between a U+ ion and an F atom will, under the equilibrium conditions prevailing result in a U+ ion and a F atom as the most probable outcome. The equilibrium conditions do not provide suff~cient energy for the collision to result in electron transfer and discharge of the ion. The potential for allowing collisions also means that the plasma can be operated in a relatively dense state allowing a significant throughput of material. If collisions have to be avoided then as low a density of ions and atoms as possible is desirable to reduce the probabliity of collisions.
As charged particles the uranium ions are contained by the magnetic field and encouraged to pass onward through the super conducting solenoids (6). The uncharged nature of the nitrogen, oxygen and hydrogen atoms allows them to move freely, unfettered by the magnetic field and they can consequently ~e "pumped" out of the chamber (12), stream (14). Vacuum pumps can be used for this purpose.
Subsequent cooling of the stream (14) allows these materials to fall back into a recombined equilibrium typically giving N~, O, and H10 and oxides of nitrogen.
As a consequence of this aspect of the process the uranium has been separated from 'he other elements formi-ng the uranyl nitrate hexahydrate feed. Suhsequent processing of the separated uranium can be conducted as required.
The strong uniform field present in portion (16) of the process strictly confines the uranium ions.
By introducing an oxygen feed (4~) to portion (44) of the process quenching of the U ions occurs. By controlling the quench a reduction in temperature to 2500K can be affected. At this temperature as can be seen from Figure 3 the predominant form of the material is Uo. gas in an uncharged state, although other uranium oxide forms are likely to be present to a lesser degree. Once again a system in equilibrium is provided.
If desired, applying a further quenching stream (52) the temperature can be reduced still further and the uranium oxide rapidly-bro~lght from a gaseous state into a solid state in the form of a ceramic powder, location (54). Thi5 exits as stream (58).
The product can be subjected to further subsequent processing, for instance to upgrade it to fuel grade materials.
The process thus provides in a single modular unit for the conversion of uranyl nitrate hexahydrate feed liquor into uranium dioxide powder. A similar result with other feed compounds and/or mixtures of feed compounds can be obtained.
A single modular unit corresponding to this process having an overall length of approximately 10 m and an active region of about 1 m in diameter can process between 50 and 200 kg/hr of feed uranium.
Residence time within the unit is very low, in the order of 10 ms. This time is a reflection of the theoretical average speed at which uranium ions travel at 4000K i.e. 6 x lO~ cm/s.
Spent fuel feed In addition to converting natural uranyl nitrate hexahydrate into fuel grade materials the technique has application in other proccssing areas including reprocessing products from used fuel rods to extract the desired components.
Spent fuel consists principally of U0, powder in combination with various fission products, generally of less than 60 atomic weight, low levels of --U and plutonium. By processing this material into a nitrate liquor and introducing the liquor to the process described above the following separations can be affected.
Applying the apparatus of Figure l once more, in the initial chamber (12) following plasma generation the -~'U, plutonium isotopes and - U (whicn makes up most of the fuel) all ionise. Most of the fission products, as well as N, H, 0, remain in a non-io;nised state and consequentl~ are not constrained by the magnetic field. Pumping of these ~aterials out into stream (14) is thus possible.
The product stream (14) may be subjected to further processing, including a further process step or steps according to this-invention to separate components, isotopes or elements of interest fro the other species in the stream.
It is then possible to collect and/or subject the product stream (16) remaining in the magnetic field to further processing. The product stream (16) may be quenched as described above to produce a solid product. As far as subsequent processing is concerned the product may be subjected to conventional enrichment téchniques. These may be used to separate adequately the~~U, -'~land plutonium isotopes from one another as desired and so achieve a reactor grade material.
Titanium tetrachloride ~eed As illustrated in an alternative embodiment, partial view, in Figure 4 the feed material may be provided with an additional system to provide or ensure the required ionisation of the selected component or components.
In this particular example the feed material consists of titanium tetrachloride and the desired product is titanium metal, but the technique is equally applicable to a wide range of feed materials.
In this unit the feed (Z) passes through a plasma generator (4) and is contained in a magnetic field (8).
The plasma temperature is such that the feed materials are reduced to discrete atoms and may b~ partially ionised.
In this form the feed then passes-through an electron cyclotron resonance unit (102) which causes further energy input to the plasma due to collision of the high energy electrons with the components. According to the appropriate phase diagrams and at the energy level of collisions provided, as a consequence of the overall energy level of the system certain components, titanium in this case, are ionised whereas others, chlorine, remain in un-ionised form. The selective ionisation is due to the equilibrium states of the species, between ionised and non-ionised, which prevail.
The material then ~asses into chamber (12) where the un-charged chlorine can be removed from the magnetic field as process stream (14). the chlorine can be recycled to earlier stages in the overall process involved in the production of titanium tetrachloride.
The remaining component, titanium, and processing steps may be treated as presented in Figure l or subjected to other processing.
Uranium metal production The technique in another embodiment, as illustrated in Figure 5, also offers a convenient production technique for uranium metal. It is e~ually applica~le for the recovery of other elements by the separation of other feed materials into its constituent elements.
Conventional techniques employ the type of concentration, denitration, reduction and hydrofluorination techniques discussed above before the uranium fluoride is converted to metallic form by reactiny it with magnesium.
The present process on the other hand offers a convenient way for separating the uranium metal from the uranyl nitrate hexahydrate feed.
Uranyl nitrate hexahydrate feed (200) is introduced into the apparatus. The feed consists elementally of uranium, nitrogen, oxygen and hydrogen. The microwave or RF type plasma generator (202) very rapidly subjects the feed to a tempèrature of around 4COOK.
Even with a short re~idence time this is sufficient to break the feed material down into its discrete elemental forms and in many cases down to discrete atoms. Thus the feed is converted to U, N, N., O" H etc. with some U+. The atomised feed is contained in the plasma, the plasma being contained by the magnetic field (204) generated by magnets (206~.
Whilst the plasma itself may have caused partial ionisation of some of the elements present, an electron cyclotron resonance aerial (~08) is provided to cause the desired degree of ionisation. Tlle aerial (208) imparts energy , . ~ . .
to electrons present within the plasma and the increased energy of the electrons is such that on collision with the components of the feed energy is transferred. According to the equilibrium applicable to the species involved in the collision under the prevailing conditions, ionisation occurs for some components, but not for others. The likelihood of ionisation for the various parts of the feed varies in the manner discussed above. Thus uranium for instance is ionised at a lower energy level of electron excitation than oxygen, hydrogen and the like.
As a consequence, by the time the process stream reaches chamber (210) it consists of the ionised and un-ionised components. The un-ionised components can be pumped out of the chamber (210) into product stream (214) as they are not restrained by the magnetic field. The charged co~ponents, principally uranium, continue on in the process stream (212) with the plasma being contained by further magnets (216).
Introduction of a chemical material (218) into the stream (212) effects the desired reaction or phase change on the separated charged components. Thus by providing argon at a relatively low energy level, for instance lOOK the charqed components can be converted to un-charged components and into the product form very rapidly due to the collision between the cool stream (218) and the stream (212). In the embodiment shown this transition is shown as beiny affected by one chemical material introduction stage but a first -stage to convert the material from charged to ~n-charged form and a second to convert it from a gaseous to solid form is also envisaged. The inert nature of the gas added gives cooling without the risk of chemical combination with the uranium.
Uranium metal thus results.
The nature of the chemical material (218) and the energy level at which it is added can be used to control the form, structure, and chemical composition of the product originating in chamber (220) and in the product stream (224). Thus the introduction of oxygèn could be used to convert the uranium for instance into Uo, as an al.ernative to the careful control of the energy level with regard to oxygen introduced or the introduction of an inert gas to reduce the uranium ions to uranium metal forms.
A similar process route can be used to produce uranium metal starting from uranium tetrafluoride produced during the hydrofluorination stage discussed above in relation to the extraction of uranium from primary sources.
Processing of the first product stream (214) to make use of the elemental constituents is also envisaged. For instance, in this case fluorine can be recovered from the stream for subsequent reuse in the earlier stayes of the material processing.
Uranium hexafluoride feed In an alternative process using this technique the feed material (200) consists of uranium hexafluoride. Selective ionisation of this feed leads to charged uranium ions and un-charged fluo~- ne atoms. The separation of these in chamber (210) leads to an uranium ion stream (212) and fluorine stream (214). The subsequent production of uranium metal as product (224) and the re-use of the fluorine either in the nuclear fuel processing cycle or in other applications is possible.
The application of this process is particularly envisaged for treatment of the depleted stream leaving the chemical or physical enrichment process discussed above. The depleted stream contains uranium hexafluoride, the concentration of 235UF6 in which is low, the 235UFG have been extracted as far as possible for further use, the vast majority of the uranium hexafluoride heing 238UF6. Presently this material has no significant use and is stored as uranium hexafluoride over long periods. Uranium hexafluoride is relatively volatile and not an ideal storage form.
The present technique offers the possibility of taking this depleted stream, or stored amounts of this product, and processing it to obtain useful materials. The liberated fluorine can be returned to the processing cycle for reuse, for instance, and the new end product, uranium metal is presented .. ... . .
in a more readily and conveniently stored form or is made available for use.
Fluorine and depleted U metal can therefore be produced.
By controlling the chemical species added to the uranium ions, for instance during a quench, other compounds can also be generated, for instance uranium nitride, uranium carbide and uranium oxide products can all be made.
A further embodiment of the invention is illustrated schematically in Fi~ure 6 in illustrating a further apparatus.
The description of the devicè will be made in relation to separating uranium from uranium hexafluoride feed, but other applications can readily ~e made for this apparatus.
The uranium hexafluoride feed liquor is introduced in stream (300) as a vapour. The feed is rapidly converted to a plasma by a radio frequency plasma generator (302). The plasma generator operates at 2KPa in order to ensure essentially equilibrium ionisation levels for the desired components of the feed due to high levels of collisions.
Contact parts within the plasma generator may ~e formed from ceramic fluorides in order to give the necessary physical properties to withstand the conditions involved. The system may employ copper surface which is cooled by contact with water containing tubes. The water flow is used to lower the temperature of the copper walls and gives rise to condensation of the uranium fluoride forms on the walls. This chemically and thermally insulates the copper. Eventually an e~uil'ibrium state develops with a given thickness of the uranium fluoride deposited on the wall. A self-lining effect is thus provided.
The plasma generated exits the generator (302) through nozzle (304) and is contained by magnetic field, schematically illustrated (306). An approximately 30mm radius nozzle is used to maintain the pressure ~ithin the plasma generator (304) and to give the desired flow rate.
On leaving the plasma generator and entering zone 1 (308) the plasma will expand giving rise to cooling. However, the work done against the magnetic field by the uranium ions will result in partial re-heatinq. If appropriate additional energy W O 97/34684 - PCT/~B97/00671 can be introduced into the plasma during its subsequent progress through the apparatus to maintain the temperature at a leveL on which the desired components remain ionised. This energy may be provided by radio fre~uency means. The desired selectivity based on an equilibrium is thus maintained.
The beam of material leaving the plasma generator tends to fan out as the distance from the plasma generator increases.
The barriers (310, 312) defining the various zones take this expansion into account in their selected aperture diameters.
The containing field is approximately 0.1 tesla in strength. Such levels can be provided by conventional electro magnetics although super conducting magnets may be employed.
A magnetic field of this strength confines the uranium ions to a radius of 180mm or so following a travel distance of 3m from the nozzle. The zones / stages are each lm in length. The radius of the expanding beam is approximately proportional to the fourth route of the distance travelled.
Within zone 1 (308) outlets (314) to a vacuum pump, not shown, are provided. These allow first waste streams to be drawn off from the apparatus, the waste streams comprising non-charged material, principally fluorine. Aluminium may be used for the waste stream lines.
The pressure in zone 1 is around 13Pa and during its travel through that zone the fluorine pressure in the material beam reduces substantially to tnat pressure. The excess fluorine over this is pumped o~f through outlets (314) using commercially available pumps.
The reduced fluorine content beam then passes into zone 2 (316) through the gap (31~) in barrier (310).
The second zone (318) is operated at a lower pressure than the first, approximately 5Pa and once again the fluorine content in the beam reduces towards this pressure as the material passes through the zone.
The beam then passes into zone 3 (320) through gap (322) in barrier (312j.
This zone is again operated at a still lower pressure, approximately 2Pa, with the excess fluorine being pumped off through outlets (324).
The significantly deple~ed fluorine b2am then ~asses on to outlet (326) for subsequent handling.
The ionised, gaseous uranium ma~ be contacted ~ith a grid of some description to discharge the charge and reduce the energy of the uranium to a s~ate in which it is solid or liquid. The introduction of chemical materials to effect a quenching and/or cooling ~ction may be considered. In this regard the u.se of inert gases to cool the uranium may be preferred so that a ohemical combination ~.~ith the ~ases ~oes not occur. Met~ilic uranium arises as a result. The uranium may be cooled sufficient~y to provide it as a solid or alternativeiy may only be partially cooled to leave it in liquid form.
The fluorine remaining in the uranium product stream (326) may be readily vGlatised, as a ur~nium fluorid~, from the bulk of the uranium product and recycled. When the uranium is collected as a liquid the separation may conveniently be carried out in situ. The volatis~d UF will largely be converted to UF~, which can be recycled.
Similar separations are po~si~le for UFJ, TiCl~ and other metal halides.
Provision for collectin~ fluorine releas~d from the liquid by off gassing may be provi~ed.
Ceramic fluoride or graphite materials may be used to form the liquid coll2ction ves~el.
For a 12kg uranium per hour feed a 5.7kg/hr fluorine feed arises. Of this fluorine 3.6);g~hr is e~pected to be pumped off fro -one 1; 1.3kg/hr pumped off from zone 2; 0.5~/hr pumped off from zone 3; and 0.3~g/hr to remain in the ~ranium produc~
stream (326). Off gassing of the fluorine from this product as UF3 and / or UFJ results in a very pure uranium product, ie, a fluorine content in the parts per million ran~e.
~ he various en~bodimen~s set out herein are closel~
related to each other and it stlould be appreciated tha.
features discussed explicitly with reyard to one or more aspects or embodiments are applicable to the others also.
FUEL MATERIALS
This invention concerns improvements in and relating to processing, particularly, but not exclusively to the processing of nuclear fuel materials and materials involved in the nuclear fuel indùstry.
The production and recycling of fuel grade nuclear fuel and associated materials involve long and complex processes.
For instance, starting from mined uranium ore, in general terms the process involves taking the ex-mine grade material and gradually converting and enriching it until it is in a form and of a grade suitable for producing fuel pellets.
In~ermediate stages in the overall process route form the starting point for the production of a variety of other materials too.
The basic stages in the overall process are the concentration of the initial uranium oxides as uranyl nitrate hexahydrate; a de-nitration stage to convert the material into UO3; a reduction stage to convert the UO~ to UO~; a hydro-fluorinatlon stage to form UFJ; a further fluorination stage to produce UF~; an enrichment procedure by physical or chemical means; and the conversion of UFh in its enriched form to ceramic grade UO~ which is in a suitable form to be formed into fuel pellets.
Recycling of spent fuel similarly involves a series of complex chemical and physical steps to separate the various fission products from the depleted fuel and to upgrade the 235U
concentration in the material to a stage where once a~ain it can be employed as fuel by separating out other components present in the used fuel.
The complexities of these processes are also present in other production processing lines involved in or relating to fuel cycles, such as thorium, plutonium and gadolinium amonqst other materials. The production of uranium metal, non-enriched, for instance for use in Magnox reactors, also involves complex processing.
.. .. .
Extensive or involved processing is also encountered in the production of other materials outside the immediate nuclear fuel field. for example, the commonly employed production route for titanium, niobium and rhodium metal, amongst others, involves the rendering of the metal containing compounds into an halide form followed by its decomposition from the halide form to the metal.
Substantial processing plants, in terms of their size, capital investment and running costs, are necessary to perform the stages involved in all of these processes. Attendant problems also follow from the various processes and their requirements. For instance, processes involving fluorination involve a complex and hazardous electrolysis process to produce the fluorine required.
The present invention aims to provide an alternative processing route for many processes and/or a process for rendering materials into more useful forms and/or a process for recycling materials, together with apparatus for achieving the processes.
According to a first aspect of the invention we provide a process comprising the steps of:-a) providing a feed, the feed consisting of mixed components;
b) converting said feed into a plasma or ionised form;
c) providing at least one component in at least partially ionised form and at least one different component in at least partially non-ionised form;
d) containing said plasma / ions in 2 magnetic field; and e) separating said ionised components fro~
said non-ionised components.
The component desired may be extracted from a mlxture OL-isotopes and/or elements of both metal and non-metal nature.
The separation may be complete or partial.
The provision of the ~eed in a nitrogen containlng compound is envisaged, but provision of the feed in a fluorine containing form is particularly preferred. Feed material consisting of uranyl nitrate, uranium hexafluoride, plutonium nitrate, thorium nitrate, depleted uranyl nitrate, depleted uranium hexafluoride or mixtures thereof all represent suitable feed materials. Other suitable feed materials include spent nuclear fuel, uranium tetrafluoride and other metals in halide forms, such as titanium tetrachloride. These materials may be in hydrated form.
The mixed components may consist of two or more different elements; two or more different isotopes of the same element;
different elements together with different isotopes of one or more of those elements; or compounds and/or mixtures of compound~ incorporating different elements, different isotopes or different isotopes and different elements, and reference in this application to the term components should be taken to include all such possibilities, amongst others, unless stated to the contrary.
The feed may be introduced to the magnetic field as a gas, liquid, solid or mixture of states. A gas feed to the magnetic field is preferred.
The feed may be introduced to the plasma generation means as a gas, liquid, solid or mixture of states.
The feed may be introduced to the ionisation means as a gas, liquid, solid or mixture of states. A gas feed to the ionisation means is preferred, particularly where a plasma generator is not also provided.
The feed may be provided in gaseous form by boiling and/or evaporation and/or sublimation of a solid or liquid initial feed. The conversion to gaseous state may be effected by a furnace, microwave heater or other form of heater means.
Preferably the gas is introduced prior to ionisation Preferably all, or substantially all, of a given component is ionised. Preferably all, or substantially all, of a given component is not ionised.
Preferably some or all metallic elements present in said feed are ionised. The ionisation of metallic elements with an atomic-weight greater than 90 is particularly preferred.
Preferably some or all non-metallic elements in said feed are not ionised. Preferably all elements with an atomic weight below 90, most preferably below 70 and ideally below ~0, are left in non-ionised form. It is particularly preferred that elements such as uranium and/or plutonium and/or thorium and/or gadolinium are ionised. It is preferred that elements such as hydrogen and/or fluorine and/or oxygen and/or nitrogen are not ionised. Preferably boron is not ionised. Preferably fission products are not ionised.
The ionisation of the components may be caused by the temperature of the plasma. Additionally or alternatively the ionisation of the components may be caused by the interaction of the components with high energy electrons produced by electron cyclotron resonance.
The extent of ionisation and/or components ionised may be controlled by the energy input of and/or residence time in the electron cyclotron resonance unit.
Prefera~ly the ionisation is controlled by the level of energy input. The level of energy input may be controlled by controlling the temperature of the plasma. Preferably the energy input is not selective between components of the feed.
In this way all of the components of the feed are preferably raised to the same energy level. Preferably the ionised and non-ionised feed components are in equilibrium with one another for the prevailing conditions.
The feed material may be converted to a gas and fed to an ECR unit for ionisation. A furnace heater or evaporator may be used to convert the solid or liquid feed to gaseous / vapour form.
In a particular embodiment, therefore, the plasma may convert the feed materials to discrete atoms and electron cyclotron resonance may subsequently 9ive rise to at least partial ionisation, preferably of a selective nature.
The feed may be provided in molecular form and be converted to discrete atoms and/or elemental forms by the plasma generation and/or ionisation means and/or heating means.
The conversion to discrete atoms and/or elemental forms may give rise to partial ionisation of one or more of the resulting species. Thus a uranyl nitrate hexahydrate feed may be converted to U, N and H (discrete atomic forms), together with N2 and 02 (elemental forms), as well as U+ (ionised species).
Preferably the feed is provided in molecular form and selectively separated as discrète atoms and/or elemental forms from ionised discrete atomic forms and/or elemental forms.
This renders the technique applicable to a wider variety of materials than are possible with elemental feed and separation in elemental form or molecular feed followed by separation in molecular form.
The temperature of said plasma may be controlled to provide selective ionisation of the components in the desired way. Thus the plas~a may ionise some components in the feed but leave other components, such as fission products and/or non-metallic elements, un-ionised.
Preferably said plasma is provided at 3000 to 4500K.
Preferably said plasma is generated by microwave or radio frequency means. Preferably the plasma in the generator is operated at between 1000 and 10000 Pa. A value of 2000 +/- 10%
is preferred.
Additionally or alternatively the residence time of the feed within the plasma prior to the separation may be controlled to provide selective ionisation of the components in the desired way.
Preferably the feed is introduced into the containing magn ic field in un-ionised form. Preferably the partial ionisation process occurs within the magnetic field on an uncharged gas. The gas may be in molecular and/or atomic form.
The magnetic field may be configured to define cylindrical active ;volume in which the plasma/ions are processed. Preferabiy the plasma/ions pass along the axis of .. .. . . ..
this containment area from the plasma generation and/or ionisation means to the next, separation, stage.
Preferably the separation of ionised and un-ionised components is affected by removing the un-ionised component from the plasma, most preferably as a gas. The un-ionised components may be pumped away from the ionised component. The ionised component is contained and hence restrained by the magnetic field.
The separation of ionised from non-ionised components may be effected in a number of stàges. Preferably the stages are discrete from one another. The stages maybe separated from one another by a baffle provided with an aperture. Preferably the aperture is entirely within the containment area of the magnetic field. Preferably one or more of the stages are operated at different pressures to one or more other stages.
The pressure level may be maintained by the pumping level employed. Preferably the pressure in one or more stages near to the inlet is higher than one or more further away from the inlet. Preferably the pressure decreases for each zone relative to the preceding stage nearer the inlet. Preferably the pressure in each stage is 30% to 60% of that in the preceding stage, progressing away from the inlet.
Preferably three stages are provided. Each stage may be between 0.5 and 2m in length.
Preferably the first stage is operated at between 10 and 50 Pa. A level of 40 Pa +/- 10% is preferred.
Preferably the second stage is operated at between 5 and 20 Pa. A level of 16 Pa +/- 10% is preferred.
Preferably the third stage is operated at between 2 and 10 Pa. A level of 7 Pa +/- 10% is preferred.
The separated un-charged components may be recycled for subsequent use and/or subjected to further processing. ~his may include further selective ionisation and / or selective processing to separate different components.
The separated charged components are preferably still contained in a ~agnetic field. The separated charged components may be subjected to further processing including selective de-ionising; de-ionising followed by further selective ionisation; or other selective processing to separate differe-nt components.
The charged components may be cooled, and/or discharged to provide a liquid and/or solid uncharged product. The charged components may be collected on an earthed or charged grid, plate, electrode or mass of the product itself. The charged components may be collected in a vessel or container.
A reservoir of liquid may be provided in the vessel or container.
The temperature conditions may be controlled to purify the collected components by vaporising off impurities. The impurities may be vaporised in the form of compounds with the metal and / or collected component. Vaporisation of halides is envisaged.
The collected charged components may be periodically or continuously removed from the collection point.
The method may comprise the further step of introducing a chemical material, preferably at a controlled ~inetic energy level, and contacting this with the remaining charged component(s), the kinetic energy level of the charged component and chemical material being such that an un-charged component or particle results. The component may still be present as a gas.
The chemical material may consist of a material selected to give the desired uncharged particle and / or end product, such as oxygen or an inert gas as the chemical material. The chemical material may be added at a temperature of between lOOK
and 2000K and particularly lOoK to 500K. The component and chemical material may be combined in the resulting particle.
An oxide represents a potential form.
The temperature of the combined form may be controlled so as to provide the particle in the desired form. A temperature of 2500K is preferred with uranium so as to present the uranium as gaseous UO? as the principle torm.
A step may be provided in which a further chemical material is added to the un-char~ed component so as to reduce the kinetic energy level to a stage where a solid product is produced. Alternatively or additionally the kinetic energy level -reduction can be provided by impacting the uncharged component on a surface, preferably a cooled surface. The kinetic energy level reduction for the un-charged particle may occur very rapidly so as to avoid undesired intermediate equilibrium forms of the product. A transition period of <2 ms is preferred.
The further chemical material may be the same or different from the chemical material previously added.
Preferably the product of the process is the desired compound, element or isotope and preferably at the desired grade. Ceramic grade metal oxide is a particularly preferred product of the process although pure metal can also be produced in this way. Uranium, piutonium, thorium and indeed MOX
products can be produced by controlling the process conditions.
According to a second aspect of the invention we provide separation apparatus, said apparatus comprising:
a) a plasma / ion generator;
b) means for selectively ionising a feed material of mixed components;
c) magnetic field generating means producing a magnetic field for containing the plasma / ions; and d) means to remove un-charged components from the magnetic field.
The feed may be provided as a solid, liquid or gas.
A furnace, heater, microwave source, evaporator or other heating means may be used to heat and/or vaporise and/or sublime and/or gasify and/or evaporate the feed.
Preferably the plasma/ions are generated by microwave or radio frequency heating. The ionisation of the components may be caused by the temperature of the plasma.
Preferably the plasma is heated to between 3000 and 4500K
and most preferably 4000K + or - 10%. Preferably the outlet from the plasma / ion generator is between 20 and 40 mm in radius.
The plasma generator may act as the means for selectively ionising the feed material mixed components. Alternatively or additionally high energy electron collisions produced by electron cyclotron resonance means may provide the means for selectively ionising the feed material of mixed components.
The feed may be fed to the ECR as a molecular and/or atomic gas.
Preferably the extent of ionisation and/or components ionised are controlled by the level cf energy input. The energy level may be controlléd by the temperature. Preferably the feed is excited evenly. Preferably t.he energy input is not selective between components present. Preferably the partial ionisation/partial non-ionisation of the feed resulting is at equilibrium for the prevailiny conditions.
The containing magnetic field may be axially aligned.
Preferably the magnetic field generating means comprises one or more solenoids. Preferably the magnets are provided in an annular or cylindrical assembly. In this way a central containment area is defined by the magnetic field, preferably of cylindrical configuration. Preferably the magnetic field is provided as a containment field most preferably in an axial alignment. Field strengths in excess of 0.075 tesla or in excess of 0.1 tesla may be used for this purpose.
Preferably the feed is introduced to the magnetic field before ionisation.
Preferably the separation is affected by removing the un-ionised component from the plasma. Preferably the means for removing un-charged components comprise a pump unit.
Preferabl~ the charged components are retained in the magnetic field.
The un-ionised components may be separated from the feed in one or more stages. Preferably one or more outlets through which the un-ionised components are withdrawn are provided in each stage.
Preferably the;sta~es are separated from one another by a baffle element. Preferably the baffle is provided with a circular aperture throu~h ~hich the feed passes. Preferably .. , . , . , . ., .. ~ .
the apertures in the baffles are axially aligned. The diameter or size of the aperture in one or more baffles may be greater than the aperture in one or more baffles nearer the feed inlet than said aperture. Preferably the apertures increase in diameter sequentially away from the feed inlet.
Preferably the aperture has a radius substantially corresponding to the plasma / ion stream radius at that distance from the inlet. Preferably the apertu~e radius is the same or less than 10% larger than the plasma / ion stream radius at that location. Preferably the radius of one or more of the apertures is approximately proportional to the fourth root of the distance from the inlet or plasma generator nozzle.
Preferably the aperture radius is less than the radius of the containment area defined by the magnetic field at that location.
The apparatus may further provide addition means for a chemical material to the remaining process stream. Preferably the chemical material introduced is oxygen or an inert gas. It is particularly preferred that the chemical material added provides a quenching and/or cooling action to the remaining components. Preferably the chemical material on contacting the remaining components converts it from a charged to an un-charged phase. Most preferably the component is $till retained in the gaseous state following this change.
In a particularly preferred embodiment the addition of oxygen is employed as the chemical material. Preferably this is introduced at lO0 to 5001~ to give an approximate combined temperature of 2500K in combination with the charged component.
At this temperature for instance, U is retained as an un-charged gas primarily in the form U0,.
A still further means for addition of a further chemical material may be provided. Preferably this further addition converts the process stream fronl a gaseous to solid state.
Alternatively or additionally the kinetic energy level reduction can be provided by impacting the uncharged component on a surface, preferably a cooled surface. The conversio" is preferably obtained very rapidly indeed so as to restrict any intervening equilibrium states forming. Preferably the product is a ceramic grade fuel material, such as UO?.
According to a third aspect of the invention we provide a process comprising the steps of:-a) providing a feed, the feed consisting of mixed components;
b) converting said feed into a plasma/ionised form;
c) providing at least one component in at least partially ionised form and at least one component in at least partially non-ionised form;
d) containing said plasma/ions in a magnetic field; and e) separating said ionised components from said non-ionised components; and further comprising converting at least some of the separated ionised component or components to an un-charged form.
The component may be converted to uncharged form by reducing its kinetic energy level, i.e. to condense it.
The component may be converted to uncharged form by impacting it on a surface, preferably a cooled surface.
The component may be converted to uncharged form by addition of a chemical material. A combination of one or more of these may be used.
Preferably the chemical material is added at a predetermined kinetic energy level so as to give the desired un-charged form. Most preferably the un-charqed form is in a gaseous form. Conversion of one, or a portion of one or more components to the un-charged form, whilst retaining one or more other components, or a portion of one or more other components and/or a portion of the first component or components in charged form is envisaged.
The addition of the chemical material, or the addltion of further chemical material in a further stage, may be such so as to reduce the kinetic energy level to a stage where a solid product is produced.
_ The chemical material added may react with the component or may simply reduce its kinetic energy level. The component may be produced in elemental or compound form.
Preferably the transition from un-charged gaseous particle to solid product occurs very rapidly. A transition period of less than 2 ms is preferred.
The separation of uranium and fluorine from a uranium hexafluoride feed is one potential use. Additionally the separation of uranium from uranyl nitrate hexahydrate and other feed forms is envisaged.
The further processing and subsequent use of the un-charged components separated from the charged components is envisaged. The production or recycling of fluorine using this route is a particularly preferred form.
This aspect of the invention may of course include any of the features or possibilities discussed elsewhere in this application, including those relating to the ion/plasma generation, its containment, the manner of the separation and others.
According to a fourth aspect of the invention we provide separation apparatus said apparatus comprising:-a) a plas~.a / ion generator;
b) means for selectively ionising the feed material of mixed components;
c) magnetic field generating means producing a containing magnetic field- for the plasma / ions;
d) means for removing un-charged components from the magnetic field; and e) means for converting at least some of the separated charged components to unchar~ed form.
The component may be converted to uncharged form by reducing its ~inetic energy levei, i.e. to condense it.
The component may be converted to uncharged form by impacting it on a surface, preferably a cooled surface.
The component may be converted to uncharged form by addition of a chemical material. ~ combination of one or more of these may be used.
The chemical material may he introduced in a single or in multiple stages. Where multiple stages are used it is preferred that the various inlets oe spaced from one another along the direction of the process stream travel. Thus first means may be provided to effect a transition from a charged to un-charged state and second or further stages may be provided to convert the un-charged component to the solid state or to the desired chemical composition. The production of both elemental and compound forms of the desired product is envisaged.
of course other feat~res of the apparatus or methods discussed elsewhere in this application can be equally relevant to this aspect.
According to a fifth aspect of the invention we provide components, materials, compounds, elements, or isotopes separated according to the first and/or third aspects of the invention and / or using the apparatus of the second and/or fourth aspects of the invention and/or further processed forms thereof.
The separated components may be different elements presented in the feed. Thus the separation of uranium from fluorine is envisaged, as is the separation of other elements present in one or more given compounds from each other. The production of ceramic grade metal oxides suitable for fuel use is envisaged.
The degree of separation between the components may be substantially complete or only partial. Thus processes in which a proportion of the component in the feed is extracted as un-charged components ir, the process whilst the majority of that component continues into the product stream produced from the charged components is envisayed.
of course the un-charyed first or second product stream may constitute the useful and aimed for separated component as much as the final end product from the charqed component.
, W O 97/34684 PC~/GB97/00671 According to an sixth aspect of the invention we provide a fuel pellet, fuel rod or fuel assembly or part for a nuclear reactor- incorporating the product, or a further processed product, of any of the first to fifth aspects of the invention.
Various embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings in which:-Figure 1 illustrates schematically a firstembodiment of the invention;
Figure 2 illuslrates a phase diagram for uranium, oxygen, nitrogen and hydrogen;
Figure 3 is a phase diagram for U+, UO, UO, and UO~;
Figure 4 schematically illustrates a partial view of a second embodiment of the invention;
Figure 5 schematically illustrates a third embodiment of the invention; and Figure 6 schematically illustrates a fourth embodiment of the invention.
The techniques of the present invention offer versatile processing systems which can be successfully employed with a variety of starting materials and states and produce a variety of product materials, states and forms.
Uranyl nitrate hexahydrate feed As illustrated in Figure 1 the feed to be processed is introduced according to arrow 2. In this particular example the feed material consists of a uranyl nitrate hexahydrate feed liquor. The feed liquor passes through a plasma yenerator (4) which rapidly heats the feed liquor to around 4000K. The plasma generator (4) may be a microwave or RF type plasma generator. Control of the plasma temperature can readily be provided.
Conducting solenoids in array (G) produce a high intensity magnetic field whose lines of force are schematically represented (8). By the stage at ~hich the feed is ionised within the plasma generator it is already within the confines of this magnetic field.
~ he conducting solenoids are se~ to produce a field intensity in excess of 0.1 tesla.
As a consequence of the plasma generator (4) the feed material enters chamber (12) at a highly elevated temperature.
At this temperature the uranyl nitrate hexahydrate breaks down into its component atoms. This allows processing of the feed material according to its individual atomic make up rather than needing an elemental feed or processing the feed only according to differences between the molecules which are either subsequently ionised or not.
As can be seen from the phase diagram provided in Figure 2 at 4000K and under the type of conditions experienced in chamber (12) uranium atoms are charged, U+, line 20.
Conversely at this temperature the bulk of the nitrogen, oxygen, and hydrogen are un-charged atoms or molecules as seen by the lines of Figure 2 which represent the nitrogen, N, line 22; oxygen, 0, line ?4; and hydrogen, H, line 26; ions all in gaseous form.
The selective ionisation occurs as a result of the overall energy level of the system. Thus the species which are ionised under the prevailing conditions and the species which are not, are determined by the equilibrium state for that species under those conditions. The selective ionisation obtained is, therefore, stable and long lasting allowing the subsequent processing to be carried out witnout pressure of time.
If energy is only selectively inputted to certain species within the system then selective ionisation can be obtained.
However, collisions between ionised and non-ionised species in such a case result in energy trans~er which can result in the ionisation of the previously non-ionised species and/or the discharge of the previously ionised species. In such a case separation must be performed very rapidly or the selective nature will decay prior tc any significant selectivity being obtained in the separation.
In the equilibrium state plasma of the present system collisions are not only tolerable they are desirable to ensure even distribution of the energy input throughout the plasma.
Collisions, however, have no detrimental effect as, for example, a collision between a U+ ion and an F atom will, under the equilibrium conditions prevailing result in a U+ ion and a F atom as the most probable outcome. The equilibrium conditions do not provide suff~cient energy for the collision to result in electron transfer and discharge of the ion. The potential for allowing collisions also means that the plasma can be operated in a relatively dense state allowing a significant throughput of material. If collisions have to be avoided then as low a density of ions and atoms as possible is desirable to reduce the probabliity of collisions.
As charged particles the uranium ions are contained by the magnetic field and encouraged to pass onward through the super conducting solenoids (6). The uncharged nature of the nitrogen, oxygen and hydrogen atoms allows them to move freely, unfettered by the magnetic field and they can consequently ~e "pumped" out of the chamber (12), stream (14). Vacuum pumps can be used for this purpose.
Subsequent cooling of the stream (14) allows these materials to fall back into a recombined equilibrium typically giving N~, O, and H10 and oxides of nitrogen.
As a consequence of this aspect of the process the uranium has been separated from 'he other elements formi-ng the uranyl nitrate hexahydrate feed. Suhsequent processing of the separated uranium can be conducted as required.
The strong uniform field present in portion (16) of the process strictly confines the uranium ions.
By introducing an oxygen feed (4~) to portion (44) of the process quenching of the U ions occurs. By controlling the quench a reduction in temperature to 2500K can be affected. At this temperature as can be seen from Figure 3 the predominant form of the material is Uo. gas in an uncharged state, although other uranium oxide forms are likely to be present to a lesser degree. Once again a system in equilibrium is provided.
If desired, applying a further quenching stream (52) the temperature can be reduced still further and the uranium oxide rapidly-bro~lght from a gaseous state into a solid state in the form of a ceramic powder, location (54). Thi5 exits as stream (58).
The product can be subjected to further subsequent processing, for instance to upgrade it to fuel grade materials.
The process thus provides in a single modular unit for the conversion of uranyl nitrate hexahydrate feed liquor into uranium dioxide powder. A similar result with other feed compounds and/or mixtures of feed compounds can be obtained.
A single modular unit corresponding to this process having an overall length of approximately 10 m and an active region of about 1 m in diameter can process between 50 and 200 kg/hr of feed uranium.
Residence time within the unit is very low, in the order of 10 ms. This time is a reflection of the theoretical average speed at which uranium ions travel at 4000K i.e. 6 x lO~ cm/s.
Spent fuel feed In addition to converting natural uranyl nitrate hexahydrate into fuel grade materials the technique has application in other proccssing areas including reprocessing products from used fuel rods to extract the desired components.
Spent fuel consists principally of U0, powder in combination with various fission products, generally of less than 60 atomic weight, low levels of --U and plutonium. By processing this material into a nitrate liquor and introducing the liquor to the process described above the following separations can be affected.
Applying the apparatus of Figure l once more, in the initial chamber (12) following plasma generation the -~'U, plutonium isotopes and - U (whicn makes up most of the fuel) all ionise. Most of the fission products, as well as N, H, 0, remain in a non-io;nised state and consequentl~ are not constrained by the magnetic field. Pumping of these ~aterials out into stream (14) is thus possible.
The product stream (14) may be subjected to further processing, including a further process step or steps according to this-invention to separate components, isotopes or elements of interest fro the other species in the stream.
It is then possible to collect and/or subject the product stream (16) remaining in the magnetic field to further processing. The product stream (16) may be quenched as described above to produce a solid product. As far as subsequent processing is concerned the product may be subjected to conventional enrichment téchniques. These may be used to separate adequately the~~U, -'~land plutonium isotopes from one another as desired and so achieve a reactor grade material.
Titanium tetrachloride ~eed As illustrated in an alternative embodiment, partial view, in Figure 4 the feed material may be provided with an additional system to provide or ensure the required ionisation of the selected component or components.
In this particular example the feed material consists of titanium tetrachloride and the desired product is titanium metal, but the technique is equally applicable to a wide range of feed materials.
In this unit the feed (Z) passes through a plasma generator (4) and is contained in a magnetic field (8).
The plasma temperature is such that the feed materials are reduced to discrete atoms and may b~ partially ionised.
In this form the feed then passes-through an electron cyclotron resonance unit (102) which causes further energy input to the plasma due to collision of the high energy electrons with the components. According to the appropriate phase diagrams and at the energy level of collisions provided, as a consequence of the overall energy level of the system certain components, titanium in this case, are ionised whereas others, chlorine, remain in un-ionised form. The selective ionisation is due to the equilibrium states of the species, between ionised and non-ionised, which prevail.
The material then ~asses into chamber (12) where the un-charged chlorine can be removed from the magnetic field as process stream (14). the chlorine can be recycled to earlier stages in the overall process involved in the production of titanium tetrachloride.
The remaining component, titanium, and processing steps may be treated as presented in Figure l or subjected to other processing.
Uranium metal production The technique in another embodiment, as illustrated in Figure 5, also offers a convenient production technique for uranium metal. It is e~ually applica~le for the recovery of other elements by the separation of other feed materials into its constituent elements.
Conventional techniques employ the type of concentration, denitration, reduction and hydrofluorination techniques discussed above before the uranium fluoride is converted to metallic form by reactiny it with magnesium.
The present process on the other hand offers a convenient way for separating the uranium metal from the uranyl nitrate hexahydrate feed.
Uranyl nitrate hexahydrate feed (200) is introduced into the apparatus. The feed consists elementally of uranium, nitrogen, oxygen and hydrogen. The microwave or RF type plasma generator (202) very rapidly subjects the feed to a tempèrature of around 4COOK.
Even with a short re~idence time this is sufficient to break the feed material down into its discrete elemental forms and in many cases down to discrete atoms. Thus the feed is converted to U, N, N., O" H etc. with some U+. The atomised feed is contained in the plasma, the plasma being contained by the magnetic field (204) generated by magnets (206~.
Whilst the plasma itself may have caused partial ionisation of some of the elements present, an electron cyclotron resonance aerial (~08) is provided to cause the desired degree of ionisation. Tlle aerial (208) imparts energy , . ~ . .
to electrons present within the plasma and the increased energy of the electrons is such that on collision with the components of the feed energy is transferred. According to the equilibrium applicable to the species involved in the collision under the prevailing conditions, ionisation occurs for some components, but not for others. The likelihood of ionisation for the various parts of the feed varies in the manner discussed above. Thus uranium for instance is ionised at a lower energy level of electron excitation than oxygen, hydrogen and the like.
As a consequence, by the time the process stream reaches chamber (210) it consists of the ionised and un-ionised components. The un-ionised components can be pumped out of the chamber (210) into product stream (214) as they are not restrained by the magnetic field. The charged co~ponents, principally uranium, continue on in the process stream (212) with the plasma being contained by further magnets (216).
Introduction of a chemical material (218) into the stream (212) effects the desired reaction or phase change on the separated charged components. Thus by providing argon at a relatively low energy level, for instance lOOK the charqed components can be converted to un-charged components and into the product form very rapidly due to the collision between the cool stream (218) and the stream (212). In the embodiment shown this transition is shown as beiny affected by one chemical material introduction stage but a first -stage to convert the material from charged to ~n-charged form and a second to convert it from a gaseous to solid form is also envisaged. The inert nature of the gas added gives cooling without the risk of chemical combination with the uranium.
Uranium metal thus results.
The nature of the chemical material (218) and the energy level at which it is added can be used to control the form, structure, and chemical composition of the product originating in chamber (220) and in the product stream (224). Thus the introduction of oxygèn could be used to convert the uranium for instance into Uo, as an al.ernative to the careful control of the energy level with regard to oxygen introduced or the introduction of an inert gas to reduce the uranium ions to uranium metal forms.
A similar process route can be used to produce uranium metal starting from uranium tetrafluoride produced during the hydrofluorination stage discussed above in relation to the extraction of uranium from primary sources.
Processing of the first product stream (214) to make use of the elemental constituents is also envisaged. For instance, in this case fluorine can be recovered from the stream for subsequent reuse in the earlier stayes of the material processing.
Uranium hexafluoride feed In an alternative process using this technique the feed material (200) consists of uranium hexafluoride. Selective ionisation of this feed leads to charged uranium ions and un-charged fluo~- ne atoms. The separation of these in chamber (210) leads to an uranium ion stream (212) and fluorine stream (214). The subsequent production of uranium metal as product (224) and the re-use of the fluorine either in the nuclear fuel processing cycle or in other applications is possible.
The application of this process is particularly envisaged for treatment of the depleted stream leaving the chemical or physical enrichment process discussed above. The depleted stream contains uranium hexafluoride, the concentration of 235UF6 in which is low, the 235UFG have been extracted as far as possible for further use, the vast majority of the uranium hexafluoride heing 238UF6. Presently this material has no significant use and is stored as uranium hexafluoride over long periods. Uranium hexafluoride is relatively volatile and not an ideal storage form.
The present technique offers the possibility of taking this depleted stream, or stored amounts of this product, and processing it to obtain useful materials. The liberated fluorine can be returned to the processing cycle for reuse, for instance, and the new end product, uranium metal is presented .. ... . .
in a more readily and conveniently stored form or is made available for use.
Fluorine and depleted U metal can therefore be produced.
By controlling the chemical species added to the uranium ions, for instance during a quench, other compounds can also be generated, for instance uranium nitride, uranium carbide and uranium oxide products can all be made.
A further embodiment of the invention is illustrated schematically in Fi~ure 6 in illustrating a further apparatus.
The description of the devicè will be made in relation to separating uranium from uranium hexafluoride feed, but other applications can readily ~e made for this apparatus.
The uranium hexafluoride feed liquor is introduced in stream (300) as a vapour. The feed is rapidly converted to a plasma by a radio frequency plasma generator (302). The plasma generator operates at 2KPa in order to ensure essentially equilibrium ionisation levels for the desired components of the feed due to high levels of collisions.
Contact parts within the plasma generator may ~e formed from ceramic fluorides in order to give the necessary physical properties to withstand the conditions involved. The system may employ copper surface which is cooled by contact with water containing tubes. The water flow is used to lower the temperature of the copper walls and gives rise to condensation of the uranium fluoride forms on the walls. This chemically and thermally insulates the copper. Eventually an e~uil'ibrium state develops with a given thickness of the uranium fluoride deposited on the wall. A self-lining effect is thus provided.
The plasma generated exits the generator (302) through nozzle (304) and is contained by magnetic field, schematically illustrated (306). An approximately 30mm radius nozzle is used to maintain the pressure ~ithin the plasma generator (304) and to give the desired flow rate.
On leaving the plasma generator and entering zone 1 (308) the plasma will expand giving rise to cooling. However, the work done against the magnetic field by the uranium ions will result in partial re-heatinq. If appropriate additional energy W O 97/34684 - PCT/~B97/00671 can be introduced into the plasma during its subsequent progress through the apparatus to maintain the temperature at a leveL on which the desired components remain ionised. This energy may be provided by radio fre~uency means. The desired selectivity based on an equilibrium is thus maintained.
The beam of material leaving the plasma generator tends to fan out as the distance from the plasma generator increases.
The barriers (310, 312) defining the various zones take this expansion into account in their selected aperture diameters.
The containing field is approximately 0.1 tesla in strength. Such levels can be provided by conventional electro magnetics although super conducting magnets may be employed.
A magnetic field of this strength confines the uranium ions to a radius of 180mm or so following a travel distance of 3m from the nozzle. The zones / stages are each lm in length. The radius of the expanding beam is approximately proportional to the fourth route of the distance travelled.
Within zone 1 (308) outlets (314) to a vacuum pump, not shown, are provided. These allow first waste streams to be drawn off from the apparatus, the waste streams comprising non-charged material, principally fluorine. Aluminium may be used for the waste stream lines.
The pressure in zone 1 is around 13Pa and during its travel through that zone the fluorine pressure in the material beam reduces substantially to tnat pressure. The excess fluorine over this is pumped o~f through outlets (314) using commercially available pumps.
The reduced fluorine content beam then passes into zone 2 (316) through the gap (31~) in barrier (310).
The second zone (318) is operated at a lower pressure than the first, approximately 5Pa and once again the fluorine content in the beam reduces towards this pressure as the material passes through the zone.
The beam then passes into zone 3 (320) through gap (322) in barrier (312j.
This zone is again operated at a still lower pressure, approximately 2Pa, with the excess fluorine being pumped off through outlets (324).
The significantly deple~ed fluorine b2am then ~asses on to outlet (326) for subsequent handling.
The ionised, gaseous uranium ma~ be contacted ~ith a grid of some description to discharge the charge and reduce the energy of the uranium to a s~ate in which it is solid or liquid. The introduction of chemical materials to effect a quenching and/or cooling ~ction may be considered. In this regard the u.se of inert gases to cool the uranium may be preferred so that a ohemical combination ~.~ith the ~ases ~oes not occur. Met~ilic uranium arises as a result. The uranium may be cooled sufficient~y to provide it as a solid or alternativeiy may only be partially cooled to leave it in liquid form.
The fluorine remaining in the uranium product stream (326) may be readily vGlatised, as a ur~nium fluorid~, from the bulk of the uranium product and recycled. When the uranium is collected as a liquid the separation may conveniently be carried out in situ. The volatis~d UF will largely be converted to UF~, which can be recycled.
Similar separations are po~si~le for UFJ, TiCl~ and other metal halides.
Provision for collectin~ fluorine releas~d from the liquid by off gassing may be provi~ed.
Ceramic fluoride or graphite materials may be used to form the liquid coll2ction ves~el.
For a 12kg uranium per hour feed a 5.7kg/hr fluorine feed arises. Of this fluorine 3.6);g~hr is e~pected to be pumped off fro -one 1; 1.3kg/hr pumped off from zone 2; 0.5~/hr pumped off from zone 3; and 0.3~g/hr to remain in the ~ranium produc~
stream (326). Off gassing of the fluorine from this product as UF3 and / or UFJ results in a very pure uranium product, ie, a fluorine content in the parts per million ran~e.
~ he various en~bodimen~s set out herein are closel~
related to each other and it stlould be appreciated tha.
features discussed explicitly with reyard to one or more aspects or embodiments are applicable to the others also.
Claims (37)
1. A process comprising the steps of:
a) providing a feed, the feed consisting of mixed components;
b) converting said feed into a plasma or ionised form;
c) providing at least one component in at least partially ionised form and at least one different component in at least partially non-ionised form;
d) containing said plasma / ions in a magnetic field; and e) separating said ionised components from said non-ionised components.
a) providing a feed, the feed consisting of mixed components;
b) converting said feed into a plasma or ionised form;
c) providing at least one component in at least partially ionised form and at least one different component in at least partially non-ionised form;
d) containing said plasma / ions in a magnetic field; and e) separating said ionised components from said non-ionised components.
2. A process according to claim 1 in which the component desired is extracted from a mixture of isotopes and/or elements of both metal and non-metal nature.
3. A process according to claim 1 or claim 2 in which the feed is provided in gaseous form by boiling and/or evaporation and/or sublimation of a solid or liquid initial feed.
4. A process according to any of claims 1 to 3 in which some or all metallic elements present in said feed are ionised.
5. A process according to claim 4 in which metallic elements with an atomic weight greater than 90 are ionised.
6. A process according to any of claims 1 to 5 in which the ionisation of the components is caused by the temperature of the plasma and/or by the interaction of the components with high energy electrons produced by electron cyclotron resonance.
7. A process according to any of claims 1 to 6 in which the ionisation is controlled by the level of energy input.
8. A process according to any of claims 1 to 7 in which the energy input is not selective between components of the feed.
9. A process according to any of claims 1 to 8 in which the ionised and non-ionised feed components are in equilibrium states for the prevailing conditions.
10. A process according to any of claims 1 to 9 in which the feed is provided in molecular form and selectively separated as discrete atoms.
11. A process according to any of claims 1 to 10 in which the feed is introduced into the containing magnetic field in un-ionised form.
12. A process according to any of claims 1 to 11 in which the separation of ionised and un-ionised components is affected by removing the un-ionised component from the plasma, whereas the ionised component is restrained by the magnetic field.
13. A process according to any of claims 1 to 12 in which separation is affected in a plurality of stages and in which the stages are operated at different pressures to one another, the pressure in one or more stages near to the inlet being higher than one or more further away from the inlet.
14. A process according to claim 13 in which three stages are provided, the first zone is operated at between 10 and 50 Pa, the second zone is operated at between 5 and 20 Pa and the third zone is operated at between 2 and 10 Pa.
15. A process according to any of claims 1 to 14 in which the separated un-charged components are recycled for subsequent use and / or subjected to further processing.
16. A process according to any of claims 1 to 15 in which the charged components are cooled, and / or discharged to provide a liquid or solid uncharged product.
17. A method according to any of claims 1 to 16 in which the method comprises the further step of introducing a chemical material, at a given kinetic energy level, and contacting this with the remaining charged component(s), the kinetic energy level of the charged component and chemical material being such that an un-charged component or particle results.
18. A method according to claim 17 in which the components and further chemical material are combined in the resulting particle.
19. Separation apparatus, said apparatus comprising:
a) a plasma / ion generator;
b) means for selectively ionising the feed material of mixed components;
c) magnetic field generating means for producing a magnetic field for containing the plasma / ions; and d) means to remove un-charged components from the magnetic field.
a) a plasma / ion generator;
b) means for selectively ionising the feed material of mixed components;
c) magnetic field generating means for producing a magnetic field for containing the plasma / ions; and d) means to remove un-charged components from the magnetic field.
20. Apparatus according to claim 19 in which the plasma /
ions are generated by microwave or radio frequency heating.
ions are generated by microwave or radio frequency heating.
21. Apparatus according to claim 19 or claim 20 in which a furnace, heater, microwave source or evaporator are used to heat and / or vaporise the feed.
22. Apparatus according to claims 19, 20 or 21 in which the partial ionisation / partial non-ionisation of the feed resulting is at equilibrium.
23. Apparatus according to any of claims 19 to 22 in which the means for removing un-charged components comprise a pump unit.
24. Apparatus according to any of claims 19 to 23 in which the un-ionised components are separated from the feed in one or more stages.
25. Apparatus according to claim 24 in which the stages are separated from one another by a baffle element provided with an aperture.
26. Apparatus according to claim 25 in which the aperture has a radius substantially corresponding to the plasma / ion stream radius at that distance from the inlet, and where the radius of one or more of the apertures is approximately proportional to the fourth root of the distance from the inlet or plasma generator nozzle.
27. Apparatus according to any of claims 19 to 26 in which the apparatus further provides means for addition of a chemical material to the remaining process stream to provide a quenching and/or cooling action to the remaining components.
28. A process comprising the steps of:
a) providing a feed, the feed consisting of mixed components;
b) converting said feed into a plasma /
ionised form;
c) providing at least one component in at least partially ionised form and at least one component in at least partially non-ionised form;
d) containing said plasma / ions in a magnetic field; and e) separating said ionised components from said non-ionised components; and further comprising converting at least some of the separated ionised component or components to an un-charged form.
a) providing a feed, the feed consisting of mixed components;
b) converting said feed into a plasma /
ionised form;
c) providing at least one component in at least partially ionised form and at least one component in at least partially non-ionised form;
d) containing said plasma / ions in a magnetic field; and e) separating said ionised components from said non-ionised components; and further comprising converting at least some of the separated ionised component or components to an un-charged form.
29. A process according to claim 28 in which the component is converted to uncharged form by reducing its kinetic energy level.
30. A process according to claim 28 or 29 in which the component is converted to uncharged form by impacting it on a surface, preferably a cooled surface.
31. A process according to any of claims 20 to 30 in which the component is converted to uncharged form by addition of a chemical material.
32. A process according to claim 31 in which the chemical material is added at a predetermined kinetic energy level so as to give the desired un-charged form in a gaseous form.
33. A process according to claim 31 or 32 in which the addition of the chemical material, or the addition of further chemical material in a further stage, is such so as to reduce the kinetic energy level to a stage where a solid product is produced.
34. Separation apparatus said apparatus comprising:
a) a plasma / ion generator;
b) means for selectively ionising the feed material of mixed components;
c) magnetic field generating means producing a containing magnetic field for the plasma / ions;
d) means for removing un-charged components from the magnetic field; and e) means for converting at least some of the separated charged components to uncharged form.
a) a plasma / ion generator;
b) means for selectively ionising the feed material of mixed components;
c) magnetic field generating means producing a containing magnetic field for the plasma / ions;
d) means for removing un-charged components from the magnetic field; and e) means for converting at least some of the separated charged components to uncharged form.
35. Separation apparatus according to claim 34 in which the chemical material is introduced in multiple stages, the various inlets being spaced from one another along the direction of the process stream travel.
36. Components, materials, elements, or isotopes separated according to any of claims 1 to 35.
37. A fuel pellet, fuel rod or fuel assembly for a nuclear reactor incorporating the product, or a further processed product according to any of claims 1 to 36.
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
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GBGB9605435.8A GB9605435D0 (en) | 1996-03-15 | 1996-03-15 | Improvements in and relating to processing |
GBGB9610606.7A GB9610606D0 (en) | 1996-03-15 | 1996-05-21 | Improvements in and relating to processing |
GB9704078A GB9704078D0 (en) | 1996-03-15 | 1997-02-23 | Improvements in and relating to processing |
GB9610606.7 | 1997-02-27 | ||
GB9605435.8 | 1997-02-27 | ||
GB9704078.6 | 1997-02-27 |
Publications (1)
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CA2248870A1 true CA2248870A1 (en) | 1997-09-25 |
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CA 2248870 Abandoned CA2248870A1 (en) | 1996-03-15 | 1997-03-12 | Separation of isotopes by ionisation for processing of nuclear fuel materials |
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US (1) | US6267850B1 (en) |
EP (1) | EP0904146B1 (en) |
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BR (1) | BR9708204A (en) |
CA (1) | CA2248870A1 (en) |
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SK (1) | SK126398A3 (en) |
TR (1) | TR199801834T2 (en) |
WO (1) | WO1997034684A1 (en) |
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DE69806730T2 (en) * | 1997-02-25 | 2002-11-28 | British Nuclear Fuels Plc | METHOD AND DEVICE FOR SEPARATING AND / OR COLLECTING IONIZED SPECIES |
US6203669B1 (en) | 1997-11-14 | 2001-03-20 | Archimedes Technology Group, Inc. | Nuclear waste separator |
GB9900836D0 (en) * | 1999-01-15 | 1999-03-31 | British Nuclear Fuels Plc | Improvements in and relating to processing materials |
US7064740B2 (en) * | 2001-11-09 | 2006-06-20 | Sharp Laboratories Of America, Inc. | Backlit display with improved dynamic range |
US7571814B2 (en) * | 2002-02-22 | 2009-08-11 | Wave Separation Technologies Llc | Method for separating metal values by exposing to microwave/millimeter wave energy |
JP4757201B2 (en) * | 2003-12-18 | 2011-08-24 | シャープ株式会社 | Dynamic gamma for liquid crystal displays |
US8395577B2 (en) | 2004-05-04 | 2013-03-12 | Sharp Laboratories Of America, Inc. | Liquid crystal display with illumination control |
US7602369B2 (en) | 2004-05-04 | 2009-10-13 | Sharp Laboratories Of America, Inc. | Liquid crystal display with colored backlight |
US7872631B2 (en) | 2004-05-04 | 2011-01-18 | Sharp Laboratories Of America, Inc. | Liquid crystal display with temporal black point |
US7777714B2 (en) | 2004-05-04 | 2010-08-17 | Sharp Laboratories Of America, Inc. | Liquid crystal display with adaptive width |
US7898519B2 (en) | 2005-02-17 | 2011-03-01 | Sharp Laboratories Of America, Inc. | Method for overdriving a backlit display |
US8050511B2 (en) | 2004-11-16 | 2011-11-01 | Sharp Laboratories Of America, Inc. | High dynamic range images from low dynamic range images |
US8050512B2 (en) | 2004-11-16 | 2011-11-01 | Sharp Laboratories Of America, Inc. | High dynamic range images from low dynamic range images |
US20060233685A1 (en) * | 2005-04-15 | 2006-10-19 | Janes Clarence W | Non-aqueous method for separating chemical constituents in spent nuclear reactor fuel |
US8121401B2 (en) | 2006-01-24 | 2012-02-21 | Sharp Labortories of America, Inc. | Method for reducing enhancement of artifacts and noise in image color enhancement |
US9143657B2 (en) | 2006-01-24 | 2015-09-22 | Sharp Laboratories Of America, Inc. | Color enhancement technique using skin color detection |
US9056272B2 (en) * | 2006-02-28 | 2015-06-16 | Tarek A. Z. Farag | Isotopes separation and purification in an electrolytic medium |
US8941580B2 (en) | 2006-11-30 | 2015-01-27 | Sharp Laboratories Of America, Inc. | Liquid crystal display with area adaptive backlight |
RU2453620C1 (en) * | 2011-05-26 | 2012-06-20 | Федеральное государственное бюджетное учреждение Национальный исследовательский центр "Курчатовский институт" | Procedure for processing uranium hexafluoride and device of implementing same |
EP3036197B1 (en) * | 2013-08-23 | 2018-12-19 | P&T Global Solutions, LLC | Systems and methods for isotopic water separation |
CN113118449A (en) * | 2019-12-31 | 2021-07-16 | 有研工程技术研究院有限公司 | Physical separation method and device for multi-component metal substance |
CN115845610A (en) * | 2023-02-20 | 2023-03-28 | 北京核力同创科技有限公司 | Separation method and system of titanium isotope, electronic device and storage medium |
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DE1943588C1 (en) * | 1969-08-27 | 1977-12-22 | Kernverfahrenstechnik Gmbh | Method and device for separating an at least partially ionized gas mixture into a lighter and a heavier fraction |
US4093856A (en) | 1976-06-09 | 1978-06-06 | Trw Inc. | Method of and apparatus for the electrostatic excitation of ions |
FR2363364A1 (en) * | 1976-09-07 | 1978-03-31 | Thomson Csf | ISOTOPIC SEPARATION PROCESS AND INSTALLATION FOR ITS IMPLEMENTATION |
US4213043A (en) | 1977-07-20 | 1980-07-15 | Trw Inc. | Method for flowing a large volume of plasma through an excitation region |
US4208582A (en) * | 1977-12-05 | 1980-06-17 | Trw Inc. | Isotope separation apparatus |
JPS5811026A (en) * | 1981-07-04 | 1983-01-21 | ジエイ・エル・ハツシユフエルド | Method and device for separating substance having different atomic weight |
US4786478A (en) * | 1984-07-26 | 1988-11-22 | Conoco Inc. | Method and apparatus for isotope separation |
FR2705584B1 (en) * | 1993-05-26 | 1995-06-30 | Commissariat Energie Atomique | Isotopic separation device by ion cyclotron resonance. |
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1997
- 1997-02-23 GB GB9704078A patent/GB9704078D0/en active Pending
- 1997-03-12 JP JP53322397A patent/JP2000506776A/en not_active Ceased
- 1997-03-12 BR BR9708204A patent/BR9708204A/en not_active Application Discontinuation
- 1997-03-12 AU AU19326/97A patent/AU1932697A/en not_active Abandoned
- 1997-03-12 RU RU98118698A patent/RU2216390C2/en not_active IP Right Cessation
- 1997-03-12 EP EP97907180A patent/EP0904146B1/en not_active Expired - Lifetime
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- 1997-03-12 CZ CZ982933A patent/CZ293398A3/en unknown
- 1997-03-12 ES ES97907180T patent/ES2182034T3/en not_active Expired - Lifetime
- 1997-03-12 AT AT97907180T patent/ATE222140T1/en not_active IP Right Cessation
- 1997-03-12 CA CA 2248870 patent/CA2248870A1/en not_active Abandoned
- 1997-03-12 WO PCT/GB1997/000671 patent/WO1997034684A1/en not_active Application Discontinuation
- 1997-03-12 TR TR1998/01834T patent/TR199801834T2/en unknown
- 1997-03-12 CN CNB971943702A patent/CN1161178C/en not_active Expired - Fee Related
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- 1997-03-12 SK SK1263-98A patent/SK126398A3/en unknown
- 1997-03-12 US US09/142,781 patent/US6267850B1/en not_active Expired - Fee Related
- 1997-03-12 PL PL32892797A patent/PL328927A1/en unknown
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1998
- 1998-09-14 NO NO984253A patent/NO984253L/en not_active Application Discontinuation
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DE69714730T2 (en) | 2003-04-24 |
US6267850B1 (en) | 2001-07-31 |
DE69714730D1 (en) | 2002-09-19 |
EP0904146A1 (en) | 1999-03-31 |
PL328927A1 (en) | 1999-03-01 |
CN1217671A (en) | 1999-05-26 |
BR9708204A (en) | 1999-07-27 |
AU1932697A (en) | 1997-10-10 |
GB9704078D0 (en) | 1997-04-16 |
ATE222140T1 (en) | 2002-08-15 |
NO984253L (en) | 1998-11-16 |
CN1161178C (en) | 2004-08-11 |
NO984253D0 (en) | 1998-09-14 |
ES2182034T3 (en) | 2003-03-01 |
NZ331896A (en) | 2000-05-26 |
RU2216390C2 (en) | 2003-11-20 |
EP0904146B1 (en) | 2002-08-14 |
WO1997034684A1 (en) | 1997-09-25 |
SK126398A3 (en) | 1999-04-13 |
TR199801834T2 (en) | 1998-12-21 |
CZ293398A3 (en) | 1999-05-12 |
JP2000506776A (en) | 2000-06-06 |
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