EP0133449A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for decontamination of a nuclear steam generator
Assignee: Westinghouse Electric Corp
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Filing: 1984-04-27
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Granted: —
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Expires: 2004-04-27
Abstract
Abstract A method for conducting a decontamination solution into a nuclear steam generator for radioactively decontaminating the nuclear steam generator wherein the level of the decontamination solution in the heat exchange tubes of the nuclear steam generator is controlled in a manner to raise and lower, sequentially, the level of the decontamination solution in the tubes so as to replenish the decontamination solution in the tubes and to carry away the radioactive contaminants.
Inventors
- 👤 Robert David Burack
- 👤 August James Friedrich
- 👤 Albert Joseph Dietrich
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 04:30
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/04; G21F9/06; G21F9/001; G21F9/002; G21F9/004
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
A method for radioactively decontaminating a nuclear steam generator wherein a decontamination solution is introduced into a channel head of said steam generator and said channel head and a portion of the heat exchange tubes adjacent to said channel head are filled to a predetermined level with said decontamination solution for removing radioactive contaminants from the surfaces of said channel head and said tubes, characterized in that said decontamination solution is circulated through said channel head while it is maintained in said tubes, the level of said decontamination solution is lowered until said decontamination solution is drained from said tubes while decontamination solution is circulated through said channel head, and the level of said decontamination solution is then again raised until said decontamination solution reaches said predetermined level while the decontamination solution is circulated through said channel head, and the decontamination solution is then finally removed from said steam generator.
Claim 2
Independent Claim
150 words
A method for radioactively decontaminating a nuclear steam generator wherein a decontamination solution is introduced into a channel head of said steam generator and said channel head and a portion of the heat exchange tubes adjacent to said channel head are filled to a predetermined level with said decontamination solution for removing radioactive contaminants from the surfaces of said channel head and said tubes, characterized in that said decontamination solution is circulated through said channel head while it is maintained in said tubes, the level of said decontamination solution is lowered until said decontamination solution is drained from said tubes while decontamination solution is circulated through said channel head, and the level of said decontamination solution is then again raised until said decontamination solution reaches said predetermined level while the decontamination solution is circulated through said channel head, and the decontamination solution is then finally removed from said steam generator.
Claim 3
Dependent Claim
30 words
A method according to claim 1, characterized in that said decontamination solution is circulated through said channel head by simultaneously introducing and withdrawing said decontamination solution from said channel head.
Claim 4
Dependent Claim
32 words
A method according to claim 2, characterized in that the level of said decontamination solution is lowered by discontinuing introduction of said decontamination solution and increasing said withdrawal of said decontamination solution.
Claim 5
Dependent Claim
54 words
A method according to claim 3, characterized in that the level of said decontamination solution is raised by introducing said decontamination solution into said channel head at a predetermined rate while withdrawing said decontamination solution at a rate less than said predetermined rate until said decontamination solution in said tubes reaches said predetermined level.
Claim 6
Dependent Claim
34 words
A method according to claim 4, characterized in that during raising of said level of said decontamina= tion solution decontamination solution is withdrawn at a rate of approximately one half of said predetermined rate.
Claim 7
Dependent Claim
62 words
A method according to claim 5, characterized in that heated water is circulated on the secondary side of said steam generator around said tubes for heating said tubes and said decontamination solution therein to a desired temperature, and the level of said heated water on said secondary side is maintained at approximately said predetermind level of said decontamination solution in said tubes.
Claim 8
Dependent Claim
25 words
A method according to claim 6, characterized in that said heated water is maintained at approximately 930°C and circulated at approximately 100 1 per minute.
Claim 9
Independent Claim
53 words
A method according to any of claims 1 to 7, characterized in that the level of said decontamination solution is raised by introducing said decontamination solution into said channel head at a rate of approximately 400 1 per minute while withdrawing said decontamination solution at a rate of approximately 200 1 per minute.
Claim 10
Dependent Claim
39 words
A method according to claim 8, characterized in that the level of said decontamination solution is lowered by discontinuing said introduction of said decontamination solution and increasing said withdrawal of said decontamination solution to approximately 300 1 per minute.
Claim 11
Dependent Claim
17 words
A method according to claim 7, characterized in that said heated water is deionized and contains hydrazine.
Claim 12
Dependent Claim
18 words
A method according to claim 10, characterized in that said heated water comprises approximately 75-150 ppm of hydrazine.
References Cited (Backward Citations)
No citation records indexed.
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