US3953286A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic nuclear fuel pellets
Assignee: British Nuclear Fuels Ltd
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Filing: 1974-01-11
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Granted: 1976-04-27
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Expires: 1994-01-11
Abstract
Abstract Sintered nuclear fuel pellets of improved dimensional stability under irradiation are produced by controlling the production of voidage in the pellets during manufacture of the pellets.
Inventors
- 👤 Ronald Henry Watson
- 👤 Gregg Glenn Butler
- 👤 Thomas John Heal
- 👤 James Edgar Littlechild
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:48
CPC Classifications
G; G21; G21C; G21C3/00; G21C3/42; G21C3/58; G21C3/62; G21C3/623; C; C04; C04B; C04B35/00; C04B35/51; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
115 words
A sintered nuclear fuel pellet composed of metal oxide selected from the group consisting of uranium dioxide, plutonium dioxide and uranium dioxide and plutonium dioxide together, the pellet having voidage in the form of randomly distributed closed pores produced by inclusion of a fugitive pore former in the pellet prior to sintering, the mean pore size being substantially above that normally observed after sintering in the absence of a pore former the mean pore size being substantially above that normally observed after sintering, all the pores being near to their equilibrium state at the designated fuel density and each point in the fuel pellet being at most only a few grain diameters from a pore.
Claim 2
Dependent Claim
115 words
A sintered nuclear fuel pellet composed of metal oxide selected from the group consisting of uranium dioxide, plutonium dioxide and uranium dioxide and plutonium dioxide together, the pellet having voidage in the form of randomly distributed closed pores produced by inclusion of a fugitive pore former in the pellet prior to sintering, the mean pore size being substantially above that normally observed after sintering in the absence of a pore former the mean pore size being substantially above that normally observed after sintering, all the pores being near to their equilibrium state at the designated fuel density and each point in the fuel pellet being at most only a few grain diameters from a pore.
Claim 3
Dependent Claim
24 words
A sintered nuclear fuel pellet as claimed in claim 1 wherein each grain of dioxide has at least one face adjacent to a pore.
Claim 4
Dependent Claim
24 words
A sintered nuclear fuel pellet according to claim 1 made from dioxide powder having a matrix density of not less than 97.5% theoretical density.
Claim 5
Dependent Claim
46 words
A sintered nuclear fuel pellet composed of metal oxide selected from the group consisting of uranium dioxide and plutonium dioxide and uranium dioxide and plutonium dioxide together, the pellet having voidage with a mean pore size in the range 6-100 microns and substantially no connected porosity.
Claim 6
Dependent Claim
46 words
A sintered nuclear fuel pellet composed of metal oxide selected from the group consisting of uranium dioxide and plutonium dioxide and uranium dioxide and plutonium dioxide together, the pellet having voidage with a mean pore size in the range 6-100 microns and substantially no connected porosity.
Claim 7
Dependent Claim
23 words
A sintered nuclear fuel pellet as claimed in claim 3 wherein the majority of pores have a size of at least 20 microns.
Claim 8
Dependent Claim
27 words
A sintered nuclear fuel pellet as claimed in claim 3 having at most only 2.5% of the pellet volume as pores less than 5 μm in diameter.
Claim 9
Dependent Claim
55 words
A sintered nuclear fuel pellet composed of metal oxide selected from the group consisting of uranium dioxide and plutonium dioxide and uranium dioxide and plutonium dioxide together, the pellet having a density of 70-94% theoretical density and an equilibrium moisture level in air at 40% relative humidity less than 5 micrograms per gram of dioxide.
Claim 10
Dependent Claim
55 words
A sintered nuclear fuel pellet composed of metal oxide selected from the group consisting of uranium dioxide and plutonium dioxide and uranium dioxide and plutonium dioxide together, the pellet having a density of 70-94% theoretical density and an equilibrium moisture level in air at 40% relative humidity less than 5 micrograms per gram of dioxide.
Claim 11
Dependent Claim
54 words
A sintered nuclear fuel pellet composed of metal oxide selected from the group consisting of uranium dioxide and plutonium dioxide and uranium dioxide and plutonium dioxide together, the pellet having a density 70-94% theoretical density and an equilibrium moisture level in air at 40% relative humidity less than 2 micrograms per gram of dioxide.
Claim 12
Dependent Claim
54 words
A sintered nuclear fuel pellet composed of metal oxide selected from the group consisting of uranium dioxide and plutonium dioxide and uranium dioxide and plutonium dioxide together, the pellet having a density 70-94% theoretical density and an equilibrium moisture level in air at 40% relative humidity less than 2 micrograms per gram of dioxide.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-27 | 1979-10-27 | 1980-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-27 | 1983-10-27 | 1984-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-27 | 1987-10-27 | 1988-04-27 | $7700.00 | Window Closed / Lapsed |