US4581162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for solidifying radioactive waste
Assignee: Hitachi Ltd
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Filing: 1983-03-10
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Granted: 1986-04-08
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Expires: 2003-03-10
Abstract
Abstract A solid radioactive waste can be solidified by a process comprising packing a solid radioactive waste in a container, adding to the container an aqueous solution comprising an alkali silicate, a hardening agent and a fluidity-improving agent for the aqueous solution and conducting the solidification of the alkali silicate, the resulting solidified radioactive waste being excellent in weather resistance, showing no cracks and having sufficient strength.
Inventors
- 👤 Fumio Kawamura
- 👤 Tetsuo Fukasawa
- 👤 Naohito Uetake
- 👤 Kiyomi Funabashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:30
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/008; G21F9/28; G21F9/30; G21F9/301; G21F9/302
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
83 words
A process for solidifying a radioactive waste which comprises packing a plurality of solid radioactive waste pellets in a container, adding to the container an aqueous solution comprising an alkali silicate as a filler, a hardening agent for the alkali silicate, and a fluidity-improving agent for the aqueous solution and less than 50% by weight of water, and effecting solidification of the alkali silicate to give a solidified radioactive waste; said fluidity-improving agent being a naphthalenesulfonic acid-formaldehyde high condensate or a salt thereof.
Claim 2
Dependent Claim
83 words
A process for solidifying a radioactive waste which comprises packing a plurality of solid radioactive waste pellets in a container, adding to the container an aqueous solution comprising an alkali silicate as a filler, a hardening agent for the alkali silicate, and a fluidity-improving agent for the aqueous solution and less than 50% by weight of water, and effecting solidification of the alkali silicate to give a solidified radioactive waste; said fluidity-improving agent being a naphthalenesulfonic acid-formaldehyde high condensate or a salt thereof.
Claim 3
Dependent Claim
15 words
A process according to claim 1, wherein the hardening agent is an inorganic phosphate compound.
Claim 4
Dependent Claim
25 words
A process according to claim 1, wherein the salt of naphthalenesulfonic acid-formaldehyde high condensate is an alkali metal salt or alkaline earth metal salt thereof.
Claim 5
Dependent Claim
57 words
A process according to claim 3, wherein the salt of naphthalene-sulfonic acid-formaldehyde high condensate is an alkali metal salt or an alkaline earth metal salt of a mixture containing 8% by weight or less of unreacted naphthalenesulfonic acid salt, and 70% by weight or more of naphthalenesulfonic acid-formaldehyde high condensate salt having 5 or more naphthalene rings.
Claim 6
Dependent Claim
27 words
A process according to claim 1, wherein the container is a drum containing therein a basket with a constant distance from the inner walls of the container.
Claim 7
Dependent Claim
33 words
A process according to claim 1, wherein the aqueous solution is obtained by mixing an alkali silicate powder and a hardening agent powder, followed by addition of the water and the fluidity-improving agent.
Claim 8
Dependent Claim
46 words
A process according to claim 1, wherein the aqueous solution contains 25 to 65%, by weight of the alkali silicate, 3 to 50% by weight of the hardening agent, 10 to 25% by weight of water, and 0.6 to 2.4% by weight of the fluidity-improving agent.
Claim 9
Dependent Claim
38 words
A process according to claim 1, wherein the salt of naphthalenesulfonic acid-formaldehyde high condensate is represented by the formula: ##STR2## wherein M is Na, K, Li, Ca or Mg; and n is an integer of 5 or more.
Claim 10
Dependent Claim
19 words
A process according to claim 1, wherein said aqueous solution contains not more than 40% by weight of water.
Claim 11
Dependent Claim
16 words
A process according to claim 1, wherein said aqueous solution is free of a water absorbent.
Claim 12
Dependent Claim
25 words
A process according to claim 7, wherein said hardening agent is an inorganic phosphate compound, calcium carbonate, a hydrogen-type zeolite, or a strong inorganic acid.
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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) | 1989-04-07 | 1989-10-07 | 1990-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-07 | 1993-10-07 | 1994-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-07 | 1997-10-07 | 1998-04-08 | $7700.00 | Window Closed / Lapsed |