US3867510A
Expired / Lapsed
US
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Process for recovering uranium and plutonium from irradiated nuclear fuel oxides
Assignee: United States Atomic Energy Commission
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Filing: 1973-04-23
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Granted: 1975-02-18
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Expires: 1993-04-23
Abstract
Abstract This invention relates to a process for recovering uranium and plutonium from liquid-metal-cooled nuclear reactor irradiated fuel assemblies as well as a process for preparing uranium nitride, plutonium nitride and mixed uranium - plutonium nitride reactor fuels. The fuel oxides are separated from the fuel assemblies and reduced in a liquid-metal reduction solvent, thereby forming uranium and plutonium metal dissolved therein. This solvent is then contacted by a bed of particulate calcium nitride or magnesium nitride to react the dissolved uranium and plutonium with the particulate nitride to form insoluble particles of uranium nitride, plutonium nitride, and uranium plutonium nitride mixtures. The bed of reacted particles is then removed from the solvent and retorted to remove any remaining liquid solvent and to volatilize any unconverted calcium nitride or magnesium nitride. This results in recovering the uranium and plutonium in the form of uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures.
Inventors
- 👤 William E Miller
- 👤 John F Lenc
- 👤 Irvin O Winsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:37
CPC Classifications
G; G21; G21C; G21C19/00; G21C19/42; G21C19/44; G21C19/48; C; C01; C01B; C01B21/00; C01B21/06; C01B21/0615; C01B21/063; Y; Y02; Y02E; Y02E30/00; Y02E30/30; Y02W; Y02W30/00; Y02W30/50
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
115 words
A PROCESS FOR RECOVERING URANIUM AND POLUTONIUM FROM IRRADIATED NUCLEAR FUEL OXIDE COMPRISING REDUCING SAID FUEL OXIDE TO URANIUM AND PLUTONIUM METAL BY CONTACTING SAID FUEL OXIDE WITH A LIQUID-METAL REDUCING SOLVENT, SAID URANIUM AND PLUTONIUM METAL BEING DISSOLVED THEREIN; CONTACTING SAID LIQUID-METAL SOLVENT WITH PARTICULATE CALCIUM NITRIDE OR MAGNESIUM NITRIDE TO REACT SAID DISSOLVED URANIUM AND PLUTONIUM WITH THE PARTICULATE NITRIDE TO FORM INSOLUBLE PARTICLES OF URANIUM NITRIDE, PLUTONIUM NITRIDE AND URANIUM - PLUTONIUM NITRIDE MIXTURES; SEPARATING SAID INSOLUBLE PARTICLES FROM SAID LIQUID-METAL SOLVENT; AND VOLATILIZING ANY UREACTED CALCIUM NITRIDE OR MAGNESIUM NITRIDE, THEREBY RECOVERING SAID URANIUM AND PLUTONIUM IN THE FORM OF PARTICULATE URANIUM NITRIDE, PLUTONIUM NITRIDE AND URANIUM - PLUTONIUM NITRIDE MIXTURES.
Claim 2
Dependent Claim
115 words
A PROCESS FOR RECOVERING URANIUM AND POLUTONIUM FROM IRRADIATED NUCLEAR FUEL OXIDE COMPRISING REDUCING SAID FUEL OXIDE TO URANIUM AND PLUTONIUM METAL BY CONTACTING SAID FUEL OXIDE WITH A LIQUID-METAL REDUCING SOLVENT, SAID URANIUM AND PLUTONIUM METAL BEING DISSOLVED THEREIN; CONTACTING SAID LIQUID-METAL SOLVENT WITH PARTICULATE CALCIUM NITRIDE OR MAGNESIUM NITRIDE TO REACT SAID DISSOLVED URANIUM AND PLUTONIUM WITH THE PARTICULATE NITRIDE TO FORM INSOLUBLE PARTICLES OF URANIUM NITRIDE, PLUTONIUM NITRIDE AND URANIUM - PLUTONIUM NITRIDE MIXTURES; SEPARATING SAID INSOLUBLE PARTICLES FROM SAID LIQUID-METAL SOLVENT; AND VOLATILIZING ANY UREACTED CALCIUM NITRIDE OR MAGNESIUM NITRIDE, THEREBY RECOVERING SAID URANIUM AND PLUTONIUM IN THE FORM OF PARTICULATE URANIUM NITRIDE, PLUTONIUM NITRIDE AND URANIUM - PLUTONIUM NITRIDE MIXTURES.
Claim 3
Dependent Claim
68 words
The process according to claim 1 wherein said liquid-metal reducing solvent is a mixture of zinc, magnesium and calcium, and wherein said liquid-metal reducing solvent is contacted with particulate calcium nitride whereby said calcium nitride reacts with said magnesium to form particulate magnesium nitride which subsequently reacts with said dissolved uranium and plutonium to form insoluble particles of uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures.
Claim 4
Dependent Claim
48 words
The process according to claim 1 wherein said liquid-metal solvent is contacted with particulate magnesium nitride, and wherein said particulate magnesium nitride is formed by contacting particulate calcium nitride with a molten zinc-magnesium melt, said calcium nitride reacting with the magnesium in said melt to form magnesium nitride.
Claim 5
Dependent Claim
33 words
The process according to claim 1 wherein said particulate calcium nitride or magnesium nitride is in the form of a particle bed contained in a perforated container separately removable from said liquid-metal solvent.
Claim 6
Dependent Claim
175 words
A process for recovering uranium and plutonium from irradiated nuclear fuel oxide comprising contacting a molten zinc-magnesium solvent with a bed of particulate calcium nitride to react said calcium nitride with said magnesium to form a bed of particulate magnesium nitride, the calcium dissolving in said solvent so as to form a molten zinc-magnesium-calcium solvent; removing the bed of particulate magnesium nitride from said zinc-magnesium-calcium solvent; contacting said fuel oxide with said molten zinc-magnesium-calcium solvent to reduce said fuel oxide to dissolved uranium and plutonium metal and calcium oxide; contacting said molten solvent containing the dissolved uranium and plutonium metal with said bed of particulate magnesium nitride to react said uranium and plutonium with said magnesium nitride to form a bed of insoluble particles of uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures; removing said bed of insoluble particles from said molten solvent; and volatilizing any unreacted calcium nitride or magnesium nitride, thereby recovering said uranium and plutonium in the form of particulate uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures.
Claim 7
Dependent Claim
175 words
A process for recovering uranium and plutonium from irradiated nuclear fuel oxide comprising contacting a molten zinc-magnesium solvent with a bed of particulate calcium nitride to react said calcium nitride with said magnesium to form a bed of particulate magnesium nitride, the calcium dissolving in said solvent so as to form a molten zinc-magnesium-calcium solvent; removing the bed of particulate magnesium nitride from said zinc-magnesium-calcium solvent; contacting said fuel oxide with said molten zinc-magnesium-calcium solvent to reduce said fuel oxide to dissolved uranium and plutonium metal and calcium oxide; contacting said molten solvent containing the dissolved uranium and plutonium metal with said bed of particulate magnesium nitride to react said uranium and plutonium with said magnesium nitride to form a bed of insoluble particles of uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures; removing said bed of insoluble particles from said molten solvent; and volatilizing any unreacted calcium nitride or magnesium nitride, thereby recovering said uranium and plutonium in the form of particulate uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures.
Claim 8
Dependent Claim
38 words
The process according to claim 5 wherein said bed of particulate calcium nitride is maintained in contact with said molten zinc-magnesium solvent for at least 1 hour, said solvent being contiNuously agitated at a temperature of about 750*-800*C.
Claim 9
Dependent Claim
39 words
The process according to claim 6 wherein said bed of particulate magnesium nitride is maintained in contact with said molten zinc-magnesium-calcium solvent for at least 6 hours, said solvent being continuously agitated at a temperature of about 750*- 800*C.
Claim 10
Dependent Claim
155 words
A process for recovering uranium and plutonium from irradiated nuclear fuel oxide comprising contacting said fuel oxide with a molten zinc-magnesium-calcium solvent to reduce said fuel oxide to dissolved uranium and plutonium metal and calcium oxide; contacting said molten solvent containing the dissolved uranium and plutonium metal with a bed of particulate calcium nitride to react said uranium and plutonium with the bed of particulate nitride to form a bed of insoluble particles of uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures, the calcium nitride reacting with the magnesium in said molten solvent to form particulate magnesium nitride which subsequently reacts with said uranium and plutonium to form said bed of insoluble particles; removing said bed of insoluble particles from said molten solvent; and volatilizing any unreacted calcium nitride or magnesium nitride, thereby recovering said uranium and plutonium in the form of particulate uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures.
Claim 11
Dependent Claim
155 words
A process for recovering uranium and plutonium from irradiated nuclear fuel oxide comprising contacting said fuel oxide with a molten zinc-magnesium-calcium solvent to reduce said fuel oxide to dissolved uranium and plutonium metal and calcium oxide; contacting said molten solvent containing the dissolved uranium and plutonium metal with a bed of particulate calcium nitride to react said uranium and plutonium with the bed of particulate nitride to form a bed of insoluble particles of uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures, the calcium nitride reacting with the magnesium in said molten solvent to form particulate magnesium nitride which subsequently reacts with said uranium and plutonium to form said bed of insoluble particles; removing said bed of insoluble particles from said molten solvent; and volatilizing any unreacted calcium nitride or magnesium nitride, thereby recovering said uranium and plutonium in the form of particulate uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures.
Claim 12
Dependent Claim
39 words
The process according to claim 8 wherein said bed of particulate calcium nitride is maintained in contact with said molten zinc-magnesium-calcium solvent for at least 6 hours, said solvent being continuously agitated at a temperature of about 750*- 800*C.
Claim 13
Dependent Claim
27 words
The process according to claim 9 wherein said zinc-magnesium-calcium solvent contains less than 4 weight percent calcium when in contact with said bed of particulate calcium nitride.
Claim 14
Dependent Claim
151 words
In a pyrochemical process for reprocessing irradiated nuclear fuel assemblies containing uranium and plutonium oxides comprising decladding said assemblies in a molten metal, separating the uranium and plutonium oxides therefrom, contacting said oxides with a liquid-metal reducing solvent containing zinc and magnesium to reduce said oxides to uranium and plutonium metal dissolved therein, and recovering said dissolved uranium and plutonium metal from said liquid-metal reducing solvent, the improvement therein comprising contacting said liquid-metal reducing solvent containing dissolved uranium and plutonium metal with particulate calcium nitride or magnesium nitride to react said uranium and plutonium with the particulate nitride to form insoluble particles of uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures; separating said insoluble particles from said liquid-metal reducing solvent; and volatilizing any unreacted calcium nitride or magnesium nitride, thereby recovering said uranium and plutonium in the form of particulate uranium nitride, plutonium nitride and uranium -plutonium nitride mixtures.
Claim 15
Dependent Claim
151 words
In a pyrochemical process for reprocessing irradiated nuclear fuel assemblies containing uranium and plutonium oxides comprising decladding said assemblies in a molten metal, separating the uranium and plutonium oxides therefrom, contacting said oxides with a liquid-metal reducing solvent containing zinc and magnesium to reduce said oxides to uranium and plutonium metal dissolved therein, and recovering said dissolved uranium and plutonium metal from said liquid-metal reducing solvent, the improvement therein comprising contacting said liquid-metal reducing solvent containing dissolved uranium and plutonium metal with particulate calcium nitride or magnesium nitride to react said uranium and plutonium with the particulate nitride to form insoluble particles of uranium nitride, plutonium nitride and uranium - plutonium nitride mixtures; separating said insoluble particles from said liquid-metal reducing solvent; and volatilizing any unreacted calcium nitride or magnesium nitride, thereby recovering said uranium and plutonium in the form of particulate uranium nitride, plutonium nitride and uranium -plutonium nitride mixtures.
Claim 16
Dependent Claim
33 words
The improvement according to claim 11 wherein said particulate calcium nitride or magnesium nitride is in the form of a particle bed contained in a perforated container separately removable from said liquid-metal solvent.
Claim 17
Dependent Claim
112 words
A process for preparing uranium mononitride, plutonium mononitride or mixed uranium - plutonium mononitride nuclear reactor fuels comprising dissolving substantially pure uranium, plutonium or mixtures thereof in a molten metal solvent; contacting said molten metal solvent with particulate calcium nitride or magnesium nitride to react said uranium, plutonium or mixtures thereof with the particulate nitride to form insoluble particles or uranium mononitride, plutonium mononitride or uranium - plutonium mononitride mixtures; separating said insoluble particles from said molten metal solvent; and volatilizing any unreacted calcium nitride or magnesium nitride, resulting thereby in substantially pure particles of uranium mononitride, plutonium mononitride or uranIum - plutonium mononitride mixtures for use as fuel in nuclear reactors.
Claim 18
Dependent Claim
112 words
A process for preparing uranium mononitride, plutonium mononitride or mixed uranium - plutonium mononitride nuclear reactor fuels comprising dissolving substantially pure uranium, plutonium or mixtures thereof in a molten metal solvent; contacting said molten metal solvent with particulate calcium nitride or magnesium nitride to react said uranium, plutonium or mixtures thereof with the particulate nitride to form insoluble particles or uranium mononitride, plutonium mononitride or uranium - plutonium mononitride mixtures; separating said insoluble particles from said molten metal solvent; and volatilizing any unreacted calcium nitride or magnesium nitride, resulting thereby in substantially pure particles of uranium mononitride, plutonium mononitride or uranIum - plutonium mononitride mixtures for use as fuel in nuclear reactors.
Claim 19
Dependent Claim
34 words
The process according to claim 13 wherein said particulate calcium nitride or magnesium nitride is in the form of a particle bed contained in a perforated container separately removable from said molten metal solvent.
References Cited (Backward Citations)
US3510434A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |