Patent US3994822A successfully refreshed from Google Patents.
US3994822A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation for storage of fission products
Assignee: United Kingdom Atomic Energy Authority
•
Filing: 1975-01-29
•
Granted: 1976-11-30
•
Expires: 1995-01-29
Abstract
Abstract A method of preparing waste fission products for storage comprising combining graphite powder and a carbonaceous binder into one component, mixing this component with alpha-silicon carbide, and sprinkling this mixture on to waste fission product particles as the particles are tumbled in the presence of a solvent to form a tacky "overcoating" around the particles. The "overcoated" particles are warm pressed to form a "green" body, then the temperature is raised to carbonize the binder. The body is then heated at an elevated temperature in contact with silicon so as to melt the silicon and impregnate the body, to form a matrix of beta-silicon carbide enclosing the waste fission product particles by reaction-sintering.
Inventors
- 👤 Mario De Bacci
- 👤 Michael Stuart Thomas Price
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:47
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/28; G21F9/34
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
123 words
A method of preparing waste fission products for storage comprising: overcoating waste fission product particles by tumbling the particles and mixing therewith a powder mixture including alpha-silicon carbide, carbon and a carbonaceous thermosetting binder, while a solvent is applied to make the binder tacky; consolidating the overcoated particles at a temperature to thermoset the binder and form a green body; placing the green bodies in contact with silicon in a furnace; and reaction-sintering the green body by heating said body, initially at a temperature to carbonize the binder, and then at a temperature to melt the silicon and thereby impregnate the body therewith and form in reaction with the carbon in said body a matrix of beta-silicon carbide enclosing said waste fission products.
Claim 2
Independent Claim
123 words
A method of preparing waste fission products for storage comprising: overcoating waste fission product particles by tumbling the particles and mixing therewith a powder mixture including alpha-silicon carbide, carbon and a carbonaceous thermosetting binder, while a solvent is applied to make the binder tacky; consolidating the overcoated particles at a temperature to thermoset the binder and form a green body; placing the green bodies in contact with silicon in a furnace; and reaction-sintering the green body by heating said body, initially at a temperature to carbonize the binder, and then at a temperature to melt the silicon and thereby impregnate the body therewith and form in reaction with the carbon in said body a matrix of beta-silicon carbide enclosing said waste fission products.
Claim 3
Dependent Claim
20 words
A method as claimed in claim 1 wherein the waste fission product particles are formed from liquid waste fission products.
Claim 4
Dependent Claim
26 words
A method as claimed in claim 1, wherein the waste fission product particles are coated with one or more layers of pyrocarbon before they are overcoated.
Claim 5
Independent Claim
153 words
A method of preparing waste fission products for storage comprising combining graphite powder and a carbonaceous thermosetting binder into one component, mixing the said component with alpha-silicon carbide, overcoating waste fission product particles by sprinkling the mixed component and alpha-silicon carbide on to the waste fission product particles as the said particles are tumbled in a tumbling means and a solvent for the binder is applied to the tumbled mixture so as to make the binder tacky and the graphite powder adhere to the particles, consolidating the overcoated particles by warm pressing at a relatively low temperature to form a body, raising the temperature of the body so as to carbonise the binder, and then heating the body to about 1600° C in contact with silicon so as to melt the silicon, whereby the silicon impregnates the body and forms a matrix of beta-silicon carbide enclosing the waste fission product particles by reaction-sintering.
Claim 6
Independent Claim
153 words
A method of preparing waste fission products for storage comprising combining graphite powder and a carbonaceous thermosetting binder into one component, mixing the said component with alpha-silicon carbide, overcoating waste fission product particles by sprinkling the mixed component and alpha-silicon carbide on to the waste fission product particles as the said particles are tumbled in a tumbling means and a solvent for the binder is applied to the tumbled mixture so as to make the binder tacky and the graphite powder adhere to the particles, consolidating the overcoated particles by warm pressing at a relatively low temperature to form a body, raising the temperature of the body so as to carbonise the binder, and then heating the body to about 1600° C in contact with silicon so as to melt the silicon, whereby the silicon impregnates the body and forms a matrix of beta-silicon carbide enclosing the waste fission product particles by reaction-sintering.
Claim 7
Dependent Claim
49 words
A method as claimed in claim 4, wherein waste fission product particles are formed from liquid waste fission products by evaporation and calcination of liquid waste fission products, and agglomeration of the particles so formed to a size extending from 0.5 mm diameter to at least 2 mm diameter.
Claim 8
Dependent Claim
26 words
A method as claimed in claim 4, wherein the waste fission product particles are coated with one or more layers of pyrocarbon before they are overcoated.
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) | 1979-11-30 | 1980-05-31 | 1980-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-30 | 1984-05-31 | 1984-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-30 | 1988-05-31 | 1988-11-30 | $7700.00 | Window Closed / Lapsed |