Corrosion-resistant structure for high-temperature water system and corrosion-preventing method thereof

Patent metadata

Field	Value
Publication number	US-9771482-B2
Application number	US-201514692256-A
Country	US
Kind code	B2
Filing date	Apr 21, 2015
Priority date	Nov 16, 2009
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

The present invention provides a corrosion-resistant structure for a high-temperature water system comprising: a structural material 1 ; and a corrosion-resistant film 3 formed from a substance containing at least one of La and Y deposited on a surface in a side that comes in contact with a cooling water 4 , of the structural material 1 which constitutes the high-temperature water system that passes a cooling water 4 of high temperature therein. Due to above construction, there can be provided the corrosion-resistant structure and a corrosion-preventing method capable of operating a plant without conducting a water chemistry control of cooling water by injecting chemicals.

First claim

The invention claimed is:

1. A corrosion-preventing method for a high-temperature water system of a secondary cooling system of a pressurized-water type nuclear power plant for preventing a corrosion of a structural material constituting the high-temperature water system which passes a cooling water of high temperature therein, the method comprising:
preparing a corrosion inhibitor comprising at least one substance selected from the group consisting of a La compound and a Y compound; and
depositing a prepared corrosion inhibitor on a surface in a side of the structural material which comes in contact with the cooling water having a temperature of 20° C. or higher and 350° C. or lower to form a corrosion-resistant film consisting of at least one selected from the group consisting of La 2 (CO 3 ) 3 and La 2 (C 2 O 4 ) 3 .

2. The corrosion-preventing method for the high-temperature water system according to claim 1 , further comprising
previously subjecting the surface in the side of the structural material which comes in contact with the cooling water to any one of a treatment selected from the group consisting of machining treatment, immersion treatment in high-temperature water and chemical cleaning treatment, before depositing the corrosion inhibitor.

3. The corrosion-preventing method for the high-temperature water system according to claim 1 , wherein the structural material is at least one structural material selected from the group consisting of a carbon steel, a copper alloy and a Ni-based alloy.

4. The corrosion-preventing method for the high-temperature water system according to claim 1 , wherein a deposition amount of the substance is 1 μg/cm 2 or more and 200 μg/cm 2 or less.

5. The corrosion-preventing method for the high-temperature water system according to claim 1 , further comprising
forming an oxide film of the structural material on a surface of the structural material, and then
depositing the corrosion inhibitor on a surface of the oxide film.

6. The corrosion-preventing method for the high-temperature water system according to claim 1 , wherein the corrosion-resistant film consists of La 2 (CO 3 ) 3 .

7. The corrosion-preventing method for the high-temperature water system according to claim 1 , wherein the corrosion-resistant film consists of La 2 (C 2 O 4 ) 3 .

8. A method for preventing corrosion of a secondary cooling system of a pressurized-water type nuclear power plant high-temperature water system, comprising:
depositing a corrosion inhibitor comprising at least one substance selected from the group consisting of a La compound and a Y compound on a water-contact surface of the secondary cooling system to form a corrosion resistant film on the water-contact surface of the secondary cooling system, wherein the corrosion resistant film consists of at least one selected from the group consisting of La 2 (CO 3 ) 3 and La 2 (C 2 O 4 ) 3 ,
wherein the secondary cooling system passes cooling water having a temperature of 20° C. or higher and 350° C. or lower during operation.

9. The method according to claim 8 , further comprising:
before the depositing, subjecting the water-contact surface to any one treatment selected from the group consisting of a machining treatment, an immersion treatment in high-temperature water and a chemical cleaning treatment.

10. The method according to claim 8 , wherein the structural material is at least one selected from the group consisting of a carbon steel, a copper alloy and a Ni-based alloy.

11. The method according to claim 8 , wherein a deposition amount of the substance is 1 μg/cm 2 or more and 200 μg/cm 2 or less on the water-contact surface of the structural material.

12. The method according to claim 8 , further comprising:
forming an oxide film on the water-contact surface of the structural material, then
depositing the substance on the oxide film.

13. The method according to claim 8 , wherein the corrosion-resistant film consists of La 2 (C 2 O 4 ) 3 .

14. The method according to claim 8 , wherein the depositing forms a corrosion-resistant film consisting of La 2 (CO 3 ) 3 .

Assignees

• Toshiba Kk

Inventors

• Okamura Masato
• Shibasaki Osamu
• Negishi Koji
• Yamamoto Seiji
• Hirasawa Hajime
• Yamazaki Kenji
• Kaneko Tetsuji

Classifications

• F22B37/025

  Devices and methods for diminishing corrosion, e.g. by preventing cooling beneath the dew point · CPC title

• C08K5/098 Primary

  Metal salts of carboxylic acids · CPC title

• C08K3/26

  Carbonates; Bicarbonates · CPC title

• C09D5/08 Primary

  Anti-corrosive paints · CPC title

• C23F11/18

  using inorganic inhibitors · CPC title