Patent US4686067A successfully refreshed from Google Patents.
US4686067A
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Process for eliminating deposits formed in a steam generator of a pressurized water nuclear reactor
Assignee: Electricite de France SA
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Filing: 1984-12-28
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Granted: 1987-08-11
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Expires: 2004-12-28
Abstract
Abstract Process for the elimination of corrosion products formed on the tube plate and in the gaps between the tubes and the spacer plates of a steam generator of a pressurized water nuclear reactor, in order to prevent the appearance of a corrosion phenomena, which can lead to necking or denting of tubes by oxide growth. The process consists of reacting with said oxides at between 50° and 100° C., an aqueous solution containing 6 to 8% gluconic acid, 3 to 5% citric acid, approximately 0.5% of a corrosion inhibitor and ammonia until a pH between approximately 3 and 9.5 is obtained.
Inventors
- 👤 Jean-Paul Veysset
- 👤 Jean-Jacques Camp
- 👤 Didier Noel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:12
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/001; G21F9/002; G21F9/004
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
111 words
A process for the elimination of corrosion products formed on the tube plate and in the gaps between tubes and spacer plates of a steam generator of a pressurized water nuclear reactor, in order to avoid the appearance of a corrosion phenomenon which can lead to necking or denting of tubes through oxide growth, comprising reacting with said oxides at a temperature between 50° and 100° C., an aqueous washing solution containing 6 to 8% gluconic acid, 3 to 5% citric acid, approximately 0.5% corrosion inhibitor and ammonia until a pH between approximately 3 and 9.5 is obtained and the potential of the solution is regulated to approximately 200 m V/SEC.
Claim 2
Dependent Claim
111 words
A process for the elimination of corrosion products formed on the tube plate and in the gaps between tubes and spacer plates of a steam generator of a pressurized water nuclear reactor, in order to avoid the appearance of a corrosion phenomenon which can lead to necking or denting of tubes through oxide growth, comprising reacting with said oxides at a temperature between 50° and 100° C., an aqueous washing solution containing 6 to 8% gluconic acid, 3 to 5% citric acid, approximately 0.5% corrosion inhibitor and ammonia until a pH between approximately 3 and 9.5 is obtained and the potential of the solution is regulated to approximately 200 m V/SEC.
Claim 3
Dependent Claim
24 words
A process according to claim 1, wherein said corrosion inhibitor is soluble in said aqueous washing solution and comprises a mixture of several amines.
Claim 4
Dependent Claim
45 words
A process according to either claim 1 or claim 2, wherein said washing solution contains 7.5% by weight of gluconic acid 4% by weight of citric acid, 0.4% by weight of corrosion inhibitor and ammonia in a quantity sufficient to establish a pH of 3.1.
Claim 5
Dependent Claim
24 words
A process according to claim 1, wherein in order to eliminate any existant cupric ions, the reaction temperature is kept at about 50° C.
Claim 6
Dependent Claim
23 words
A process according to claim 1, wherein the potential is regulated by adding hydrogen peroxide to or by bubbling air through the solution.
Claim 7
Dependent Claim
36 words
A process according to claim 1, wherein the temperature of said aqueous washing solution is kept at betwen 80° and 95° C. to dissolve said oxides, in particular iron oxide but other than those of copper.
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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) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |