US4659511A
Expired / Lapsed
US
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Method for solidifying radioactive waste
Assignee: Hitachi Ltd
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Filing: 1984-05-18
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Granted: 1987-04-21
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Expires: 2004-05-18
Abstract
Abstract PCT No. PCT/JP84/00250 Sec. 371 Date Jan. 16, 1985 Sec. 102(e) Date Jan. 16, 1985 PCT Filed May 18, 1984 PCT Pub. No. WO84/04624 PCT Pub. Date Nov. 22, 1984.A process for solidifying radioactive wastes, which comprises adding, to pellet or dissolved radioactive wastes, an alkali metal silicate as a filler, silicic acid, carbonic acid or an alkaline earth metal or polyvalent metal salt thereof as a hardener, and cement as an absorbent for absorbing water to be released with the progress of the reaction and, if necessary, water and mixing and solidifying the resulting mixture to thereby prevent deterioration of water-proofness due to precipitation of readily soluble salts on the surface of a solidified substance.
Inventors
- 👤 Tetsuo Fukasawa
- 👤 Masaharu Ohtsuka
- 👤 Naohito Uetake
- 👤 Yoshihiro Ozawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:22
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/04; G21F9/06; G21F9/16; G21F9/162; G21F9/165; G21F9/28; G21F9/30; G21F9/301; G21F9/302; G21F9/304
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
185 words
A method for solidifying radioactive waste which comprises mixing the radioactive waste with a solidifying agent prepared by mixing an alkali metal silicate as a solidifying filler; an inorganic compound as a hardening agent for reacting with said alkali metal silicate; cement as a water absorbent for absorbing liberated water generated in the course of the hardening reaction between said alkali metal silicate and said inorganic compound; and water; wherein said inorganic compound contains an ion able to bind with an alkali metal in said alkali metal silicate to form a low-solubility salt, said inorganic compound being a compound of a polyvalent metal ion selected from the group consisting of Ca 2+ , Mg 2+ , Al 3+ , and Fe 3+ or an H + ion and an ion selected from the group consisting of TaO 3 - , AlF 6 3- , NbO 3 - , SiF 6 2- , SiO 3 2- , BeF 4 2- , B 4 O 7 2- , F - , IO 4 - , ClO 4 - , BF 4 - and ReO 4 - .
Claim 2
Independent Claim
185 words
A method for solidifying radioactive waste which comprises mixing the radioactive waste with a solidifying agent prepared by mixing an alkali metal silicate as a solidifying filler; an inorganic compound as a hardening agent for reacting with said alkali metal silicate; cement as a water absorbent for absorbing liberated water generated in the course of the hardening reaction between said alkali metal silicate and said inorganic compound; and water; wherein said inorganic compound contains an ion able to bind with an alkali metal in said alkali metal silicate to form a low-solubility salt, said inorganic compound being a compound of a polyvalent metal ion selected from the group consisting of Ca 2+ , Mg 2+ , Al 3+ , and Fe 3+ or an H + ion and an ion selected from the group consisting of TaO 3 - , AlF 6 3- , NbO 3 - , SiF 6 2- , SiO 3 2- , BeF 4 2- , B 4 O 7 2- , F - , IO 4 - , ClO 4 - , BF 4 - and ReO 4 - .
Claim 3
Dependent Claim
35 words
A method for solidifying radioactive waste according to claim 1, wherein the content of said inorganic compound in the solidifying agent is not less than 3% by weight but not greater than 50% by weight.
Claim 4
Dependent Claim
34 words
A method for solidifying radioactive waste according to claim 1, wherein the content of said cement in the solidifying agent is not less than 3% by weight but not greater than 35% by weight.
Claim 5
Dependent Claim
34 words
A method for solidifying radioactive waste according to claim 1, wherein the content of said water in the solidifying agent is not less than 15% by weight but not greater than 40% by weight.
Claim 6
Dependent Claim
29 words
A method for solidifying radioactive waste according to claim 1, wherein said alkali metal silicate is selected from the group consisting of sodium silicate, potassium silicate and lithium silicate.
Claim 7
Dependent Claim
18 words
A method for solidifying radioactive waste according to claim 1, wherein said inorganic compound is CaSiO 3 .
Claim 8
Dependent Claim
18 words
A method for solidifying radioactive waste according to claim 1, wherein said alkali metal silicate is sodium silicate.
Claim 9
Dependent Claim
18 words
A method for solidifying radioactive waste according to claim 7, wherein said inorganic compound is CaSiO 3 .
Claim 10
Dependent Claim
31 words
A method for solidifying radioactive waste according to claim 2, wherein the content of said alkali metal silicate as a solidifying filler in the solidifying agent is about 37.5% by weight.
Claim 11
Dependent Claim
31 words
A method for solidifying radioactive waste according to claim 3, wherein the content of said alkali metal silicate as a solidifying filler in the solidifying agent is about 37.5% by weight.
Claim 12
Dependent Claim
31 words
A method for solidifying radioactive waste according to claim 4, wherein the content of said alkali metal silicate as a solidifying filler in the solidifying agent is about 37.5% by weight.
Claim 13
Dependent Claim
27 words
A method for solidifying radioactive waste according to claim 1, wherein the viscosity of the solidifying agent before it is hardened is less than about 3,000 cP.
Claim 14
Dependent Claim
26 words
A method for solidifying radioactive waste according to claim 1, wherein the radioactive waste and the solidifying agent are mixed in approximately equal amounts by weight.
Claim 15
Dependent Claim
98 words
A method for solidifying radioactive waste according to claim 1, wherein the content of said inorganic compound in the solidifying agent is not less than 3% by weight but not greater than 50% by weight; the content of said cement in the solidifying agent is not less than 3% by weight but not greater than 35% by weight; the content of said water in the solidifying agent is not less than 15% by weight but no greater than 40% by weight; and the content of said alkali metal silicate in the solidifying agent is about 37.5% by weight.
Claim 16
Dependent Claim
98 words
A method for solidifying radioactive waste according to claim 8, wherein the content of said inorganic compound in the solidifying agent is not less than 3% by weight but not greater than 50% by weight; the content of said cement in the solidifying agent is not less than 3% by weight but not greater than 35% by weight; the content of said water in the solidifying agent is not less than 15% by weight but not greater than 40% by weight; and the content of said alkali metal silicate in the solidifying agent is about 37.5% by weight.
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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) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |