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US3668283A
Expired / Lapsed
US
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Process for the fabrication of nuclear fuel elements
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1969-09-11
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Granted: 1972-06-06
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Expires: 1989-09-11
Abstract
Abstract A method of fabrication of nuclear fuel elements having high impermeability to fission gases and made up of refractory fuel particles dispersed in a carbonaceous matrix, said fuel particles being coated with a mixture of graphite and an organic diluent by means of a pelletizing process. An outer jacket for containing the coated particles is fabricated by shaping a paste formed of graphite powder and a binder, then baking and impregnating the jacket with pyrocarbon in a single operation by heating to a temperature between 850* and 1,100* C. in a gaseous hydrocarbon atmosphere.
Inventors
- 👤 Claude Moreau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:00
CPC Classifications
G; G21; G21C; G21C21/00; G21C21/02; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
22 words
A process in accordance with claim 1, wherein the baking and impregnation are carried out at a temperature between 900*C and 1,000*C.
Claim 2
Dependent Claim
26 words
A process in accordance with claim 1 wherein the nuclear fuel particles have a size prior to coating which passes through a 1, 000-micron aperture screen.
Claim 3
Dependent Claim
16 words
A process in accordance with claim 3, wherein the particles pass through a 400-micron aperture screen.
Claim 4
Dependent Claim
29 words
A process in accordance with claim 1 wherein said jacket is filled with a mixture of coated particles and of graphite powder which passes through a 100-micron aperture screen.
Claim 5
Dependent Claim
36 words
A process in accordance with claim 1, wherein the particles are coated with a first layer of graphite then with a pelletizing layer of micronized natural graphite having a thickness between 50 and 100 Mu .
Claim 6
Dependent Claim
124 words
A process of forming nuclear fuel elements comprising the steps of applying an outer coating to refractory nuclear fuel particles, spraying a mixture containing micronized graphite powder and an organic diluent on the coated nuclear fuel particles and forming an overcoating, separately shaping and drying a paste of graphite powder and binder and forming a green jacket and a closing plug for said jacket, filling said jacket with a mixture of said overcoated particles and of graphite powder having a grain size between 50 and 100 Mu , closing said jacket with said plug and then backing the filled jacket and impregnating it with pyrocarbon in a single operation by heating to a temperature between 850* and 1,100*C in an atmosphere of gaseous hydrocarbon.
Claim 7
Dependent Claim
39 words
A process in accordance with claim 7, wherein the nuclear fuel particles are overcoated by spraying onto said particles which are agitated in a rotary drum a mixture of graphite and of coal tar pitch in an organic diluent.
Claim 8
Dependent Claim
30 words
A process in accordance with claim 8, wherein the mixture contains graphite having a particle size on the order of 1 micron and coal tar pitch in suspension in benzene.
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) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |