US4671897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and apparatus for solidification of radioactive waste
Assignee: Hitachi Ltd
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Filing: 1985-02-01
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Granted: 1987-06-09
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Expires: 2005-02-01
Abstract
Abstract Radioactive waste is first converted into hardly water-soluble powder (including a water-insoluble powder) and then solidified with a hydraulic solidifier in a solidification vessel. The radioactive waste may be powdered (including granulated and encapsulated) by incorporating the radioactive waste with a substance which is capable of reacting with the water-soluble salt contained in the radioactive waste to form a hardly water-soluble salt (including a water-insoluble salt) and then powdering the mixture with drying, or by powdering the radioactive waste with drying, granulating the powder with drying and then microencapsulating the granules with a hardly water-soluble substance (including water-insoluble substance). The hardly water-soluble salts are preferably calcium salts, and the additives are preferably calcium hydroxide solution or solvent of combination of dichloromethane solution and hexane.
Inventors
- 👤 Kazuhide Mori
- 👤 Shin Tamata
- 👤 Makoto Kikuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:21
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/28; G21F9/34; G21F9/04; G21F9/06; G21F9/30; G21F9/301; G21F9/302
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
124 words
In a process for solidification of radioactive waste comprising the steps of: drying a water-soluble salts containing radioactive waste; shaping said dried radioactive waste into granules; microencapsulating said granules into water insoluble salts containing radioactive waste in microencapsulation solvents; and solidifying said microencapsulated radioactive waste with a hydraulic solidifier in a solidification vessel; the improvement comprising: said step of microencapsulating employing said microencapsulation solvents that are a dichloromethane solution and a hexane; said microencapsulating step including a first step of mixing the granules with the dichloromethane solution, thereafter the second step of cooling the mixture and removing supernatant and separating the capsules formed, and the third step of hardening the wall membrane of the capsules by adding cold hexane and thereafter drying the capsules.
Claim 2
Dependent Claim
124 words
In a process for solidification of radioactive waste comprising the steps of: drying a water-soluble salts containing radioactive waste; shaping said dried radioactive waste into granules; microencapsulating said granules into water insoluble salts containing radioactive waste in microencapsulation solvents; and solidifying said microencapsulated radioactive waste with a hydraulic solidifier in a solidification vessel; the improvement comprising: said step of microencapsulating employing said microencapsulation solvents that are a dichloromethane solution and a hexane; said microencapsulating step including a first step of mixing the granules with the dichloromethane solution, thereafter the second step of cooling the mixture and removing supernatant and separating the capsules formed, and the third step of hardening the wall membrane of the capsules by adding cold hexane and thereafter drying the capsules.
Claim 3
Dependent Claim
24 words
A process for solidification of radioactive waste according to claim 1, wherein said dichloromethane solution is an ethylcellulose solution, and said hexane is n-hexane.
Claim 4
Dependent Claim
19 words
A process for solidification of radioactive waste according to claim 2, wherein said ethylcellulose solution is about 9% weight.
Claim 5
Dependent Claim
25 words
A process for solidification of radioactive waste according to claim 2, wherein said step of solidifying adds the solidifier up to about 50 WT %.
Claim 6
Dependent Claim
72 words
In a process for solidification of radioactive waste comprising the steps of: drying a water-soluble salts containing radioactive waste; shaping said dried radioactive waste into granules; microencapsulating said granules into water insoluble salts containing radioactive waste in microencapsulation solvents; and solidifying said microencapsulated radioactive waste with a hydraulic solidifier in a solidification vessel; the improvement comprising; said step of microencapsulating employing said microencapsulation solvents that are a dichloromethane solution and a hexane.
Claim 7
Dependent Claim
72 words
In a process for solidification of radioactive waste comprising the steps of: drying a water-soluble salts containing radioactive waste; shaping said dried radioactive waste into granules; microencapsulating said granules into water insoluble salts containing radioactive waste in microencapsulation solvents; and solidifying said microencapsulated radioactive waste with a hydraulic solidifier in a solidification vessel; the improvement comprising; said step of microencapsulating employing said microencapsulation solvents that are a dichloromethane solution and a hexane.
Claim 8
Dependent Claim
24 words
A process for solidification of radioactive waste according to claim 5, wherein said dichloromethane solution is an ethylcellulose solution, and said hexane is n-hexane.
Claim 9
Dependent Claim
19 words
A process for solidification of radioactive waste according to claim 6, wherein said ethylcellulose solution is about 9% weight.
Claim 10
Dependent Claim
25 words
A process for solidification of radioactive waste according to claim 6, wherein said step of solidifying adds the solidifier up to about 50 WT %.
Claim 11
Dependent Claim
25 words
A process for solidification of radioactive waste according to claim 5, wherein said step of solidifying adds the solidifier up to about 50 WT %.
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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) | 1990-06-08 | 1990-12-08 | 1991-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-08 | 1994-12-08 | 1995-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-08 | 1998-12-08 | 1999-06-09 | $7700.00 | Window Closed / Lapsed |