US4399108A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for reprocessing and separating spent nuclear fuels
Assignee: United States Department of Energy
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Filing: 1982-01-19
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Granted: 1983-08-16
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Expires: 2002-01-19
Abstract
Abstract Spent nuclear fuels, including actinide fuels, volatile and non-volatile fission products, are reprocessed and separated in a molten metal solvent housed in a separation vessel made of a carbon-containing material. A first catalyst, which promotes the solubility and permeability of carbon in the metal solvent, is included. By increasing the solubility and permeability of the carbon in the solvent, the rate at which actinide oxides are reduced (carbothermic reduction) is greatly increased. A second catalyst, included to increase the affinity for nitrogen in the metal solvent, is added to increase the rate at which actinide nitrides form after carbothermic reduction is complete.
Inventors
- 👤 Oscar H. Krikorian
- 👤 John Z. Grens
- 👤 William H. Parrish, Sr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:05
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; Y10; Y10S; Y10S423/00; Y10S423/09; Y10S423/12
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
88 words
A method for reprocessing and separating spent nuclear fuels comprising actinide fuels, volatile and non-volatile fission products, comprising: providing a separation vessel formed of a carbon-containing material, and a molten metal solvent disposed within said separation vessel, said separation vessel including an aperture disposed within a vessel wall member; adding a first catalyst to said metal solvent which increases the solubility of carbon in said solvent; introducing spent nuclear fuels into said separation vessel; and forming CO within said molten metal solvent from actinide fuels which are oxides.
Claim 2
Independent Claim
88 words
A method for reprocessing and separating spent nuclear fuels comprising actinide fuels, volatile and non-volatile fission products, comprising: providing a separation vessel formed of a carbon-containing material, and a molten metal solvent disposed within said separation vessel, said separation vessel including an aperture disposed within a vessel wall member; adding a first catalyst to said metal solvent which increases the solubility of carbon in said solvent; introducing spent nuclear fuels into said separation vessel; and forming CO within said molten metal solvent from actinide fuels which are oxides.
Claim 3
Dependent Claim
19 words
The method according to claim 1, further comprising removing said volatile fission products and CO from said separation vessel.
Claim 4
Dependent Claim
55 words
The method according to claim 2, further comprising: introducing a non-oxidizing nitrogen-containing atmosphere into said separation vessel after said volatile fission products and CO have been removed therefrom; forming solid nitrides from said actinide fuels within said molten metal solvent; and separating said solid actinide nitrides from said molten metal solvent and non-volatile fission products.
Claim 5
Independent Claim
22 words
The method according to claims 1, 2 or 3, wherein said first catalyst is selected from Co, Ni, Fe, and mixtures thereof.
Claim 6
Independent Claim
15 words
The method according to claims 1, 2 or 3, wherein said first catalyst is Co.
Claim 7
Independent Claim
16 words
The method according to claims 1, 2 or 3, wherein said molten metal solvent is tin.
Claim 8
Independent Claim
15 words
The method according to claims 1, 2 or 3, wherein said carbon-containing material is graphite.
Claim 9
Independent Claim
26 words
The method according to claims 1, 2 or 3, wherein the weight percentage of said first catalyst in molten metal solvent is about 5.0 to 10.0.
Claim 10
Independent Claim
244 words
A method for reprocessing and separating spent nuclear fuels comprising actinide fuels, volatile and non-volatile fission products, in a molten tin solvent, comprising: providing a separation vessel formed of a carbon-containing material, said separation vessel defining a reaction region housing said molten tin solvent and a reflux region positioned adjacent to and above said reaction region, said separation vessel including an aperture disposed within a vessel wall member in a position adjacent said reflux region; adding a first catalyst to said tin solvent which increases the solubility of carbon in said solvent; maintaining said reaction region at a temperature sufficient to convert said actinide fuels to a solubilized state; maintaining said reflux region at a temperature sufficient to reflux said tin solvent, said reflux temperature being lower than said reaction region temperature; introducing spent nuclear fuels into said tin solvent; forming CO within said molten tin solvent from actinide fuels which are oxides; allowing CO and volatile fission products within said molten tin solvent, along with some molten tin, to evaporate and flow into said reflux region; removing CO and volatile fission products which are not condensable at said reflux temperature from said reflux region through said vessel aperture, leaving evaporated tin and condensable fission products in said reflux region; and allowing evaporated tin and condensable fission products disposed within said reflux region which are condensable at said reflux temperature to cool sufficiently and return to said molten tin solvent in said reaction region.
Claim 11
Independent Claim
244 words
A method for reprocessing and separating spent nuclear fuels comprising actinide fuels, volatile and non-volatile fission products, in a molten tin solvent, comprising: providing a separation vessel formed of a carbon-containing material, said separation vessel defining a reaction region housing said molten tin solvent and a reflux region positioned adjacent to and above said reaction region, said separation vessel including an aperture disposed within a vessel wall member in a position adjacent said reflux region; adding a first catalyst to said tin solvent which increases the solubility of carbon in said solvent; maintaining said reaction region at a temperature sufficient to convert said actinide fuels to a solubilized state; maintaining said reflux region at a temperature sufficient to reflux said tin solvent, said reflux temperature being lower than said reaction region temperature; introducing spent nuclear fuels into said tin solvent; forming CO within said molten tin solvent from actinide fuels which are oxides; allowing CO and volatile fission products within said molten tin solvent, along with some molten tin, to evaporate and flow into said reflux region; removing CO and volatile fission products which are not condensable at said reflux temperature from said reflux region through said vessel aperture, leaving evaporated tin and condensable fission products in said reflux region; and allowing evaporated tin and condensable fission products disposed within said reflux region which are condensable at said reflux temperature to cool sufficiently and return to said molten tin solvent in said reaction region.
Claim 12
Dependent Claim
77 words
The method according to claim 9, further comprising: raising said reflux temperature to said reaction region temperature after CO and said non-condensable volatile fission products have been removed from said reflux region; distilling said condensable volatile fission products and some tin from said molten tin solvent; removing said distilled volatile fission products and some tin from said reflux and reactive region of said separation vessel; and lowering the temperature of said reflux region to said reflux temperature.
Claim 13
Dependent Claim
38 words
The method according to claim 10, further comprising: introducing a non-oxidizing nitrogen-containing atmosphere into said separation vessel; and forming solid actinide nitrides from actinide fuels within said molten tin solvent, while substantially leaving non-volatile fission products in solution.
Claim 14
Dependent Claim
21 words
The method according to claim 11, further comprising: separating said actinide nitrides from said molten tin solvent and non-volatile fission products.
Claim 15
Independent Claim
23 words
The method according to claims 9, 10, 11 or 12, wherein said first catalyst is selected from Co, Ni, Fe, and mixtures thereof.
Claim 16
Independent Claim
16 words
The method according to claims 9, 10, 11 or 12, wherein said first catalyst is Co.
Claim 17
Independent Claim
16 words
The method according to claims 9, 10, 11 or 12, wherein said carbon-containing material is graphite.
Claim 18
Independent Claim
26 words
The method according to claims 9, 10, 11 or 12, wherein the weight percentage of first catalyst in molten tin solvent is about 5.0 to 10.0.
Claim 19
Independent Claim
21 words
The method according to claims 9, 10, 11 or 12, wherein said reaction region temperature is about 1500° to 1700° C.
Claim 20
Independent Claim
20 words
The method according to claims 9, 10, 11 or 12, wherein said reflux temperature is about 950° to 1050° C.
Claim 21
Dependent Claim
41 words
The method according to claim 11, further comprising adding a nitriding catalyst to said molten metal solvent prior to introducing said non-oxidizing nitrogen-containing gas into said separation vessel, said nitriding catalyst increasing the affinity of nitrogen in said molten metal solvent.
Claim 22
Dependent Claim
24 words
The method according to claim 19, wherein said nitriding catalyst is selected from magnesium, calcium, strontium, barium, aluminum, manganese, vanadium, chromium, and mixtures thereof.
Claim 23
Dependent Claim
12 words
The method according to claim 19, wherein said nitriding catalyst is calcium.
Claim 24
Dependent Claim
22 words
The method according to claim 19, wherein the weight percentage of said nitriding catalyst to metal solvent is about 1.8 to 2.5.
Claim 25
Independent Claim
129 words
A method for reprocessing and separating spent nuclear fuels comprising actinide fuels, volatile and non-volatile fission products, comprising: providing a separation vessel formed from a carbon-containing material housing a molten metal solvent, said separation vessel including an aperture disposed within a vessel wall member; introducing spent nuclear fuels into said separation vessel; forming CO within said molten metal solvent from actinide fuels which are oxides; removing CO and volatile fission products from said separation vessel; introducing a nitriding catalyst into said vessel which increases the affinity for nitrogen in said molten metal solvent; introducing a non-oxidizing nitrogen-containing atmosphere into said separation vessel; forming solid nitrides from said actinide fuels within said molten metal solvent; and separating said solid actinide nitrides from said molten metal solvent and non-volatile fission products.
Claim 26
Independent Claim
129 words
A method for reprocessing and separating spent nuclear fuels comprising actinide fuels, volatile and non-volatile fission products, comprising: providing a separation vessel formed from a carbon-containing material housing a molten metal solvent, said separation vessel including an aperture disposed within a vessel wall member; introducing spent nuclear fuels into said separation vessel; forming CO within said molten metal solvent from actinide fuels which are oxides; removing CO and volatile fission products from said separation vessel; introducing a nitriding catalyst into said vessel which increases the affinity for nitrogen in said molten metal solvent; introducing a non-oxidizing nitrogen-containing atmosphere into said separation vessel; forming solid nitrides from said actinide fuels within said molten metal solvent; and separating said solid actinide nitrides from said molten metal solvent and non-volatile fission products.
Claim 27
Dependent Claim
13 words
The method according to claim 23, wherein said molten metal solvent is tin.
Claim 28
Dependent Claim
24 words
The method according to claim 23, wherein said nitriding catalyst is selected from magnesium, calcium, strontium, barium, aluminum, manganese, vanadium, chromium, and mixtures thereof.
Claim 29
Dependent Claim
12 words
The method according to claim 23, wherein said nitriding catalyst is calcium.
Claim 30
Dependent Claim
22 words
The method according to claim 23, wherein the weight percentage of said nitriding catalyst to metal solvent is about 1.8 to 2.5.
Claim 31
Dependent Claim
30 words
The method according to claim 23, further comprising including a another and different catalyst to said molten metal solvent which increases the solubility of carbon in said molten metal solvent.
Claim 32
Dependent Claim
21 words
The method according to claim 28, wherein said another and different catalyst is selected from cobalt, nickel, iron, and mixtures thereof.
Claim 33
Dependent Claim
14 words
The method according to claim 28, wherein said another and different catalyst is cobalt.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |