JP5377147B2 - Method of forming nickel ferrite film on carbon steel member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming nickel ferrite film onto carbon steel member by which a period of time required for forming a nickel ferrite film can be further shortened. <P>SOLUTION: The method of forming nickel ferrite film to carbon steel member comprises: a process (S1) of connecting a film forming device to a water-feed piping made of carbon steel of BWR plant; a process (S4) of injecting chemicals containing nickel ion and formic acid into an aqueous film forming solution heated to a temperature in the range of 60 to 100&deg;C, whereby the aqueous film forming solution is supplied to the water-feed piping and a nickel metal film is formed on the inner surface of the water-feed piping; processes (S5 to S7) of injecting chemicals containing iron(II) ion and formic acid, hydrogen peroxide and hydrazine into an aqueous film forming solution containing nickel ion and formic acid, whereby an aqueous film forming solution containing iron(II) ion, hydrogen peroxide, hydrazine, nickel ion and formic acid is supplied to the water-feed piping and a nickel ferrite film is formed on the surface of the nickel metal film in the water-feed piping. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for forming a nickel ferrite film on a carbon steel member, and more particularly to a method for forming a nickel ferrite film on a carbon steel member suitable for application to a boiling water nuclear power plant.

  As power plants, for example, boiling water nuclear power plants (hereinafter referred to as BWR plants) and pressurized water nuclear power plants (hereinafter referred to as PWR plants) are known. For example, a BWR plant has a nuclear reactor in which a core is built in a nuclear reactor pressure vessel (hereinafter referred to as RPV). The cooling water supplied to the core by the recirculation pump (or internal pump) is heated by heat generated by nuclear fission of nuclear fuel material in the fuel assembly loaded in the core. A part of the heated cooling water becomes steam. This steam is led from the nuclear reactor to the turbine and rotates the turbine. The steam exhausted from the turbine is condensed in a condenser to become water. This water is supplied to the reactor as feed water. In order to suppress the generation of radioactive corrosion products in the nuclear reactor, mainly metal impurities contained in the feed water are removed by a filtration and desalination apparatus provided in the feed water pipe.

  In a power plant such as a BWR plant and a PWR plant, main components such as a reactor pressure vessel use stainless steel, a nickel-based alloy, or the like for a water contact portion with which cooling water contacts in order to suppress corrosion. . However, components such as the reactor coolant purification system, residual heat removal system, reactor isolation cooling system, core spray system, and water supply system are used to reduce the manufacturing cost of the plant or high-temperature water flowing through the water supply system. From the viewpoint of avoiding stress corrosion cracking of stainless steel caused by the above, carbon steel members are mainly used.

  However, the carbon steel members constituting the reactor coolant purification system, the residual heat removal system, the reactor isolation cooling system, the core spray system, the water supply system, and the like also have a water contact portion in contact with water. There is a risk of corrosion. In this case, if the carbon steel member is disposed on the downstream side of the purification device, the corrosion product of the carbon steel member may be a source of the radioactive corrosion product of the nuclear reactor. Moreover, it may cause the heat exchange efficiency of the secondary system of the PWR plant to decrease due to the corrosion products of the carbon steel member.

Therefore, it has been proposed to form a dense ferrite film (for example, a magnetite film or a nickel ferrite film) on the surface of a carbon steel member of a BWR plant (see, for example, JP-A-2007-182604). In this proposal, in the formation of a nickel ferrite film, a first agent containing iron (II) ions, a second agent containing nickel ions, and a third agent (oxidizing agent) that oxidizes iron (II) ions to iron (III) ions ), A film-forming aqueous solution containing a fourth agent (pH adjuster) for adjusting pH. Since the ferrite film serves as a protective film that blocks the cooling water from coming into contact with the carbon steel member, corrosion of the surface of the carbon steel member in contact with the cooling water is suppressed.

  A method of forming a ferrite film on the inner surface of a recirculation piping of a BWR plant manufactured from stainless steel is described in Japanese Patent Application Laid-Open No. 2006-38483.

JP 2007-182604 A JP 2006-38483 A

  A nickel ferrite film forming method described in JP 2007-182604 A, which forms a dense nickel ferrite film on the surface of a carbon steel member of a nuclear power plant, includes a first drug, a second drug, The third drug and the fourth drug are added in the order of the first drug, the second drug, the third drug, and the fourth drug.

  The inventors have examined the formation of a nickel ferrite film on the surface of a carbon steel member described in Japanese Patent Application Laid-Open No. 2007-182604, and found that it takes a long time to form the nickel ferrite film.

  An object of the present invention is to provide a method for forming a nickel ferrite film on a carbon steel member that can further reduce the time required to form the nickel ferrite film on the carbon steel member constituting the plant.

A feature of the present invention that achieves the above-described object is that the surface of the carbon steel member constituting the plant that is in contact with water has a pH adjusted to a value within the range of 4.0 or more and 9.0 or less, and the coating includes nickel ions A forming liquid is contacted to form a nickel metal film on the surface, and a first drug containing iron (II) ions, a second drug containing nickel ions, and iron (II) ions are formed on the surface of the formed nickel metal film. A film-forming solution that contains a third agent that oxidizes and is adjusted to a value that falls within the range of 5.5 to 9.0 by adding a pH adjuster, in the Turkey form a nickel ferrite film.

  By forming the nickel metal film on the surface of the carbon steel member, elution of iron (II) ions from the carbon steel member can be prevented when the nickel ferrite film is formed. For this reason, the time required for forming the nickel ferrite film can be shortened.

adding a first agent containing iron (II) ions and an acid, a second agent containing nickel ions, and a third agent that oxidizes iron (II) ions to iron (III) ions to a liquid containing a pH adjuster;
A liquid containing iron (II) ions, nickel ions, and a third drug and having a pH adjusted to a value within a range of greater than 6.0 and less than or equal to 9.0 is used as water for carbon steel members constituting the plant. The above object can also be achieved by first contacting the contacting surface with a nickel ferrite film on the surface.

  Since a liquid containing iron (II) ions, nickel ions and a third drug and having a pH adjusted to a value within a range of more than 6.0 and not more than 9.0 is brought into contact with the surface thereof, a carbon steel member It is possible to avoid contact with the surface of a liquid whose pH increases to 6.0 or less, in particular, a liquid that is acidic including iron (II) ions and an acid. For this reason, at the time of nickel ferrite film formation, elution of iron (II) ions from the carbon steel member can be prevented, and the time required for forming the nickel ferrite film can be shortened.

  According to the present invention, it is possible to further reduce the time required for forming the nickel ferrite film on the surface of the carbon steel member constituting the plant.

It is a flowchart which shows the procedure of the nickel ferrite membrane | film | coat formation method to the carbon steel member of Example 1 applied to the water supply piping of a BWR plant which is one suitable Example of this invention. It is explanatory drawing which shows the state which connected the film forming apparatus used when implementing the nickel ferrite film forming method shown in FIG. 1 to the water supply piping of a BWR plant. It is a detailed block diagram of the film forming apparatus shown in FIG. It is a characteristic view which shows the relationship between pH of the film formation aqueous solution which contacts a carbon steel member, and the weight change (corrosion amount) of a carbon steel member. It is explanatory drawing which shows the difference in the quantity of the nickel ferrite film formed in three methods from which the method of forming a nickel ferrite film differs on the surface of a carbon steel member. It is explanatory drawing which shows the change of the density | concentration of the element component in the depth direction from the surface of the nickel ferrite membrane | film | coat targeting the membrane | film | coat formed by the method B using the Auger spectrum method. It is explanatory drawing which shows the laser Raman spectrum in the surface of the carbon steel member in which the nickel ferrite film was formed. It is explanatory drawing which shows the inhibitory effect of the corrosion of the carbon steel member which formed the nickel ferrite film in the surface. It is a block diagram of the membrane | film | coat formation apparatus used for the nickel ferrite membrane | film | coat formation method to the carbon steel member of Example 2 applied to the water supply piping of a BWR plant which is another Example of this invention. It is a flowchart which shows the procedure of the nickel ferrite membrane | film | coat formation method to the carbon steel member of Example 3 applied to the water supply piping of a BWR plant which is another Example of this invention. It is a detailed block diagram of the film formation apparatus used for the nickel ferrite film formation method shown in FIG. It is explanatory drawing which shows the state which connected the film formation apparatus to the purification system piping in the nickel ferrite film formation method to the carbon steel member of Example 4 applied to the purification system piping of the BWR plant which is another Example of this invention. . It is a flowchart which shows the procedure of the nickel ferrite membrane | film | coat formation method to the carbon steel member of Example 5 applied to the water supply piping of a BWR plant which is another Example of this invention.

  The inventors have conducted detailed examinations and experiments for determining the cause of the formation of a nickel ferrite film on the surface of a carbon steel member described in JP-A-2007-182604, which takes a long time. Went. As for the order of addition of each drug described in Japanese Patent Application Laid-Open No. 2007-182604, the addition of the first drug (first drug containing iron (II) ions) is the same as the addition of the fourth drug (pH adjusting agent). Have gone before. As a result of the study, the inventors finally came to the conclusion that the order of addition of the drugs is a problem.

The first drug is produced by dissolving iron in formic acid (or carbonic acid) and contains formic acid (or carbonic acid) in addition to iron (II) ions. When this first agent was added to water in an amount necessary for forming the nickel ferrite film, the pH of the aqueous solution of the first agent was about 4. When the carbon steel member used in the BWR plant was immersed in an aqueous solution (dissolved oxygen concentration of 100 ppb) having a pH of 4 and 100 ° C. containing the first drug for 20 hours, the weight of the carbon steel member was as shown in FIG. It decreased by 4 × 10 ⁴ mg / dm ² compared to before immersion. This means that the carbon steel member has been corroded by the action of formic acid contained in its aqueous solution at about pH 4.
As a result, the inventors have taken a long time to form a nickel-nickel ferrite film on the carbon steel member. By first adding the first agent, the surface of the carbon steel member temporarily becomes about It was found that the weight was reduced by corrosion by exposure to an aqueous solution of pH 4.

  Moreover, the inventors changed the pH of the aqueous solution in which the carbon steel member is immersed, and performed a corrosion test on the carbon steel member. By this corrosion test, the inventors can obtain a new test result that the change in the weight of the carbon steel member is drastically reduced when the pH of the aqueous solution becomes higher than 6, as shown in FIG. did it. This means that when the pH of the aqueous solution in contact with the surface of the carbon steel member becomes higher than 6, the corrosion of the carbon steel member is rapidly reduced.

  As described in Japanese Patent Application Laid-Open No. 2007-182604, a nickel ferrite film forming method includes adding a drug to a film-forming aqueous solution by using a first drug containing iron (II) ions, a second drug containing nickel ions, When the third agent containing the oxidizing agent and the fourth agent containing the pH adjusting agent are performed in this order, the aqueous solution containing the first agent and the second agent contains the third agent and the fourth agent after contacting the carbon steel member. Until the aqueous solution contacts the surface of the carbon steel member, the aqueous solution of about pH 4 will contact the surface of the carbon steel member. The weight loss due to the corrosion of the carbon steel member in the meantime increases the time required for forming the nickel ferrite film on the surface of the carbon steel member. That is, when an aqueous solution having a pH of about 4 comes into contact with the surface of the carbon steel member, iron (II) ions are eluted from the surface of the carbon steel member into the aqueous solution. Due to the elution of the iron (II) ions, the iron (II) ions contained in the first chemical added to the aqueous solution are less likely to be adsorbed on the surface of the carbon steel member. A large amount of iron (II) ions are eluted from the inner surface of the water supply pipe 10 until the second drug containing nickel ions added after the first drug reaches the water supply pipe 10. Under the influence of such a large amount of iron (II) ion elution, the amount of adsorbed iron (II) ions on the member surface decreases. Furthermore, due to the presence of a large amount of iron (II) ions eluted from the inner surface of the water supply pipe 10 and added iron (II) ions, the degree of adsorption of nickel ions on the surface of the carbon steel member is significantly reduced. For the above reasons, the time required for forming the nickel ferrite film on the surface of the carbon steel member becomes longer. The film forming method described in Japanese Patent Application Laid-Open No. 2007-182604 is referred to as Method A for convenience.

  From the experimental results shown in FIG. 4, even when an aqueous solution having a pH of 6.0 or less comes into contact with the surface of the carbon steel member, the corrosion of the carbon steel member increases, and the iron (II) ions eluted from the surface of the carbon steel member. You can see that the amount increases. For this reason, when the aqueous solution whose pH is 6.0 or less contacts the surface of the carbon steel member, the time required for forming the nickel ferrite film on the surface of the carbon steel member becomes long.

Therefore, the inventors examined a method for preventing corrosion of the carbon steel surface. The inventors have devised a method that can suppress corrosion of the carbon steel member during the formation of the nickel ferrite film (elution of iron (II) ions from the carbon steel member) and further reduce the time required for forming the nickel ferrite film. .
Nickel ions contained in the second chemical have a smaller ionization tendency than iron ions contained in the carbon steel member. For this reason, the nickel ions in the aqueous solution adhere to the surface of the carbon steel member before the iron (II) ions. When nickel ions are present on the surface of the carbon steel member, the nickel ions are reduced according to the formula (1) to generate nickel metal on the surface of the carbon steel member. After the nickel metal grows in the form of a film on the surface of the carbon steel member, a nickel ferrite film may be formed on the surface of the nickel metal film. Here, the nickel metal film formed on the surface of the carbon steel member plays a role of an anticorrosion film for the carbon steel member together with the nickel ferrite film.

Fe + Ni ²⁺ → Fe ²⁺ + Ni (1)
After the nickel metal film is formed on the surface of the carbon steel member, nickel ions and iron ions are adsorbed on the surface of the nickel metal film, and by adding an oxidizing agent and a pH adjuster, A nickel ferrite film is formed on the surface of the nickel metal film.

Ni ²⁺ + 2Fe ³⁺ + 4H ₂ O → NiFe ₂ O ₄ + 8H ₂ O (2)
As a result of the examination described above, the inventors added a second agent containing nickel ions and an acid to water when forming a nickel ferrite film on the carbon steel member, and then iron (II) ions. It was thought that the 1st chemical | medical agent containing, the 3rd chemical | medical agent containing an oxidizing agent, and the 4th chemical | medical agent containing a pH adjuster should just be added. The addition of the second drug may be performed before the addition of the first drug or simultaneously with the addition of the first drug. The third drug and the fourth drug may be added at any time after the addition of the second drug. A method of forming a nickel metal film on the surface of the carbon steel member and forming a nickel ferrite film on the surface of the nickel metal film is referred to as method B for convenience.

In addition, as another method for suppressing the corrosion of the carbon steel member at the time of forming the nickel ferrite film, the inventors have added a fourth chemical to water and the pH is larger than 6.0 from the result shown in FIG. It was found that a pH adjuster aqueous solution having a pH value in the range of 0.0 or less was generated, and then the first drug, the second drug, and the third drug may be added to the pH adjuster aqueous solution.
Also by this method, the pH of the aqueous solution in contact with the surface of the carbon steel member becomes alkaline, and the weight loss due to corrosion of the carbon steel member during the formation of the nickel ferrite film is reduced. Therefore, when the nickel ferrite film is formed, the amount of iron (II) ions eluted from the surface of the carbon steel member is reduced, and the time required for forming the nickel ferrite film on the surface of the carbon steel member is shortened. Add a fourth drug to adjust the pH of the aqueous solution to a pH value within the range of greater than 6.0 and less than 9.0, and then add the first drug, the second drug, and the third drug. The method of forming the nickel ferrite film is referred to as Method C for convenience.

  FIG. 5 shows the amount of the nickel ferrite film formed on the surface of the carbon steel member by each method when the formation time of the nickel ferrite film is the same in method A, method B and method C. In the methods B and C, the amount of nickel ferrite film formed on the surface of the carbon steel member is larger than that in the method A. This indicates that the methods B and C can suppress the corrosion of the surface of the carbon steel member during the formation of the nickel ferrite film and can reduce the time required for forming the nickel ferrite film. The thickness of the nickel ferrite film formed by the methods B and C is larger than the thickness of the ferrite film formed on the surface of the stainless steel component described in JP-A-2006-38483.

FIG. 6 shows the result of analyzing the composition in the thickness direction of the film (including the nickel metal film and the nickel ferrite film) formed by the method B on the surface of the carbon steel member by the Auger spectrum method. In FIG. 6, the vertical axis represents the concentration of elemental components in each film and the base material, and the horizontal axis represents the depth from the surface of the nickel ferrite film. As shown in FIG. 6, the film has a two-layer structure, the surface layer is a nickel ferrite film, and the layer between the nickel ferrite film and the base material (carbon steel member) is a nickel metal film. Moreover, the composition of the nickel ferrite film was Ni _0.7 Fe _0.3 Fe ₂ O ₄ . The result of analyzing the nickel ferrite film formed by the method B on the surface of the carbon steel member by the laser Raman method is shown in FIG. In FIG. 7, the solid line shows the change in relative intensity with respect to the frequency in the film formed by Method B, the broken line shows the change in relative intensity with respect to the frequency in magnetite, and the one-point difference line shows the change in relative intensity with respect to the frequency in nickel ferrite. ing. The peak position of the film formed by Method B was different from the peak values of nickel ferrite and magnetite. This is presumably because part of nickel contained in the nickel ferrite was replaced with divalent iron ions in the film formed by the method B. This result coincided with the analysis result of the Auger spectrum.

  Inventors confirmed the corrosion inhibitory effect of the carbon steel member by experiment. The obtained corrosion inhibition effect will be described with reference to FIG. The vertical axis | shaft of FIG. 8 has shown the relative value of each weight change of the samples D, E, and F. FIG. Sample D is a sample obtained by mechanically polishing the surface of a carbon steel member. Sample E is obtained by adding a first drug and a third drug to an aqueous solution having a pH value in the range of greater than 6.0 and less than or equal to 9.0 including the fourth drug. This is a sample in which a magnetite film is formed on the surface of the carbon steel member by a method of forming a magnetite film on the surface of the carbon steel member using an aqueous solution. Sample F is a sample in which a nickel metal film and a nickel ferrite film are formed on the surface of the carbon steel member by the method B described above. As is clear from FIG. 8, the sample F in which the nickel metal film and the nickel ferrite film are formed on the surface by the method B is less reduced in weight than the samples D and E. That is, the sample F is less corroded than the samples D and E.

  The aforementioned aqueous solution having a pH value containing the fourth drug in the range of greater than 6.0 and not more than 9.0 is brought into contact with the surface, and then the first drug, second drug, and In the sample in which the nickel ferrite film is formed on the surface using the aqueous solution (film forming solution) obtained by adding the third agent, the weight decrease is less than that of the samples D and E, and is about the same as the sample F. became.

  Inventors examined the pH of the aqueous solution containing the nickel ion brought into contact with the surface of the carbon steel member when forming the nickel metal film on the surface of the carbon steel member in Method B. In order to form a nickel metal film on the surface of a carbon steel member, it is necessary to elute iron (II) ions from the carbon steel member into an aqueous solution containing nickel ions. The elution of iron (II) ions from the carbon steel member occurs even when the pH of the aqueous solution containing nickel ions is 9.0 or less. However, when the pH of the aqueous solution became smaller than 4.0 by the addition of nickel nitrate, the thickness of the nickel metal film formed on the surface of the carbon steel member became non-uniform. When the pH was 4.0 or more, the thickness of the nickel metal film formed on the surface of the carbon steel member became uniform. For this reason, in order to form a nickel metal film, it is desirable that the pH of the aqueous solution containing nickel ions brought into contact with the surface of the carbon steel member is in the range of 4.0 or more and 9.0 or less.

  After the nickel metal film is formed on the surface of the carbon steel member, the nickel metal film prevents corrosion of the carbon steel member. For this reason, in order to form a nickel ferrite film, the pH of the film forming liquid brought into contact with the nickel metal film formed on the surface of the carbon steel member can be adjusted to pH 6.0 or less. However, the pH of the film-forming solution needs to be adjusted to a range of 5.5 to 9.0 that causes a nickel ferrite film formation reaction to proceed on the surface of the nickel metal film. Even if the pH of the film forming solution used for forming the nickel ferrite film is 5.5, the nickel metal film that forms the nickel ferrite film on the surface is not adversely affected.

  Examples of the present invention reflecting the above-described examination results will be described below.

  A method for forming a nickel ferrite film on a carbon steel member of Example 1 applied to a water supply pipe of a BWR plant, which is a preferred example of the present invention, will be described with reference to FIGS. 1, 2, and 3.

A BWR plant, which is a nuclear power plant, includes a nuclear reactor 1, a turbine 3, a condenser 4, a recirculation system, a nuclear reactor purification system, a water supply system, and the like. The nuclear reactor 1 has a nuclear reactor pressure vessel (hereinafter referred to as RPV) 12 containing a core 13, and a jet pump 14 is installed in the RPV 12. The core 13 is loaded with a large number of fuel assemblies (not shown). The fuel assembly includes a plurality of fuel rods filled with a plurality of fuel pellets made of nuclear fuel material. The recirculation system includes a recirculation system pipe 22 and a recirculation pump 21 installed in the recirculation system pipe 22. The water supply system includes a condensate pump 5, a condensate purification device (for example, a condensate demineralizer) 6, a low-pressure feed water heater 8, a feed water pump 7, and a high-pressure feed water in a feed water pipe 10 that connects the condenser 4 and the RPV 12. The heater 9 is installed from the condenser 4 toward the RPV 12 in this order. In the reactor purification system, a purification system pipe 24 that connects the recirculation system pipe 22 and the feed water pipe 10 is connected to a purification system pump 24, a regenerative heat exchanger 25, a non-regenerative heat exchanger 26, and a reactor water purification device 27 in this order. It is installed. The purification system pipe 20 is connected to the recirculation system pipe 22 upstream of the recirculation pump 21.
The nuclear reactor 1 is installed in a nuclear reactor containment vessel 11 arranged in a nuclear reactor building (not shown).

  The cooling water in the RPV 12 is boosted by the recirculation pump 21, and jetted into the jet pump 14 through the recirculation system pipe 22. Cooling water existing around the nozzles of the jet pump 14 is also sucked into the jet pump 14 and supplied to the core 13. Cooling water supplied to the core 13 is heated by heat generated by fission of nuclear fuel material in the fuel rods. Some of the heated cooling water becomes steam. This steam is guided from the RPV 12 through the main steam pipe 2 to the turbine 3 to rotate the turbine 3. A generator (not shown) connected to the turbine 3 rotates to generate electric power. The steam discharged from the turbine 3 is condensed by the condenser 4 to become water. This water is supplied into the RPV 12 through the water supply pipe 10 as water supply. The feed water flowing through the feed water pipe 10 is boosted by the condensate pump 5, impurities are removed by the condensate purification device 6, and further boosted by the feed water pump 7. The feed water is heated by the low pressure feed water heater 8 and the high pressure feed water heater 9 and guided into the RPV 12. The extraction steam extracted from the turbine 3 by the extraction piping 15 is supplied to the low-pressure feed water heater 8 and the high-pressure feed water heater 9 respectively, and becomes a heating source of the feed water.

  A part of the cooling water flowing in the recirculation system pipe 22 flows into the purification system pipe 20 of the reactor purification system by driving the purification system pump 24 and is cooled by the regenerative heat exchanger 25 and the non-regenerative heat exchanger 26. Then, the water is purified by the reactor water purification device 27. The purified cooling water is heated by the regenerative heat exchanger 25 and returned to the RPV 12 through the purification system pipe 20 and the water supply pipe 10.

  Within the operation stop period of the BWR plant after the operation of the BWR plant is stopped, both ends of the circulation pipe (film forming liquid pipe) 35 of the film forming apparatus 30 which is a temporary facility are water supply pipes made of carbon steel (carbon steel). Member) 10. The operation of connecting the circulation pipe 35 to the water supply pipe 10 will be specifically described. After the operation of the BWR plant is stopped, for example, the bonnet of the valve 28 installed at the outlet of the condensate purification apparatus 6 is opened to close the condensate purification apparatus 6 side. One end of the circulation pipe 35 of the film forming apparatus 30 is connected to the flange of the valve 28. Thereby, one end of the circulation pipe 35 is connected to the water supply pipe 10 upstream of the low-pressure feed water heater 8. At the same time, a branch pipe (for example, a drain pipe or a sampling pipe) connected to the water supply pipe 10 downstream from the high-pressure feed water heater 9 is cut off by a flange or the like, and the other end of the circulation pipe 35 is branched to the water supply pipe 10 side. Connect to the flange of the tube. By connecting the circulation pipe 35 to the water supply pipe 10, a closed loop including the circulation pipe 35 and the water supply pipe 10 is formed. The film forming apparatus 30 is removed from the water supply pipe 10 after the nickel ferrite film is formed on the inner surface of the water supply pipe 10 and the processing of the solution used for forming the nickel ferrite film is completed and within the operation stop period of the BWR plant. It is. Thereafter, the operation of the BWR plant is started.

  The film forming apparatus 30 is used for both the formation of the nickel ferrite film on the inner surface of the water supply pipe 10 and the treatment of the solution used for the formation of this film. Furthermore, the film forming apparatus 30 is also used when chemical decontamination of the inner surface of the water supply pipe 10 is performed. The film forming apparatus 30 connected to the water supply pipe 10 is arranged in a turbine building (not shown) which is a radiation management area in the BWR plant.

  A detailed configuration of the film forming apparatus 30 will be described with reference to FIG. The film forming apparatus 30 includes a surge tank 31, a circulation pipe 35, an iron (II) ion implantation apparatus 85, an oxidant injection apparatus 86, a pH adjuster injection apparatus 87, a nickel ion implantation apparatus 88, a filter 51, a decomposition apparatus 64, and a cation. An exchange resin tower 60 is provided.

  The on-off valve 47, the circulation pump 48, the valve 49, the heater 53, the valves 55, 56 and 57, the surge tank 31, the circulation pump 32, the valve 33 and the on-off valve 34 are provided in the circulation pipe 35 in this order from the upstream. . A valve 50 and a filter 51 are installed in a pipe 71 that bypasses the valve 49 and is connected to the circulation pipe 35. A pipe 66 that bypasses the heater 53 and the valve 55 is connected to the circulation pipe 35. A cooler 58 and a valve 59 are installed in the pipe 66. A cation exchange resin tower 60 and a valve 61 are installed in a pipe 67 having both ends connected to the circulation pipe 35 and bypassing the valve 56. A mixed bed resin tower 62 and a valve 63 are installed in a pipe 68 having both ends connected to the pipe 67 and bypassing the cation exchange resin tower 60 and the valve 61.

  A pipe 69 in which the valve 65 and the decomposition device 64 are installed bypasses the valve 57 and is connected to the circulation pipe 35. The decomposition apparatus 64 is filled with, for example, an activated carbon catalyst in which ruthenium is impregnated on the surface of the activated carbon. A surge tank 31 is installed in the circulation pipe 35 between the valve 57 and the circulation pump 32. A pipe 70 provided with the valve 36 and the ejector 37 is connected to the circulation pipe 35 between the valve 33 and the circulation pump 32, and further connected to the surge tank 31. Potassium permanganate (oxidative decontamination agent) used to oxidize and dissolve contaminants on the inner surface of the water supply pipe 10 forming the nickel ferrite film, and Shu used to reduce and dissolve contaminants on the inner surface of the water supply pipe 10. A hopper (not shown) for supplying an acid (reductive decontamination agent) into the surge tank 31 is provided in the ejector 37.

  The iron (II) ion implantation apparatus 85 includes a chemical liquid tank 45, an injection pump 43, and an injection pipe 72. The chemical tank 45 is connected to the circulation pipe 35 by an injection pipe 72 having an injection pump 43 and a valve 41. The chemical tank 45 is filled with a drug (first drug) containing divalent iron (II) ions prepared by dissolving iron with formic acid. This drug contains formic acid. In addition, as a chemical | medical agent which dissolves iron, the organic acid or carbonic acid which becomes a counter anion of iron (II) ion can be used not only formic acid. The oxidant injection device 86 includes a chemical liquid tank 46, an injection pump 44, and an injection pipe 73. The chemical tank 46 is connected to the circulation pipe 35 by an injection pipe 73 having an injection pump 44 and a valve 42. The chemical tank 46 is filled with hydrogen peroxide which is an oxidizing agent (third chemical). The pH adjuster injection device 87 includes a chemical tank 40, an injection pump 39, and an injection pipe 74. The chemical tank 40 is connected to the circulation pipe 35 by an injection pipe 74 having an injection pump 39 and a valve 38. The chemical tank 40 is filled with hydrazine which is a pH adjuster (fourth drug).

  The nickel ion implanter 88 has a chemical tank 80, an injection pump 81, and an injection pipe 83. The chemical tank 80 is connected to the circulation pipe 35 by an injection pipe 83 having an injection pump 81 and a valve 82. The chemical tank 80 is filled with a drug (second drug) containing divalent nickel ions prepared by dissolving nickel formate with formic acid. This drug contains formic acid. In addition, as a chemical | medical agent which dissolves nickel, not only formic acid but the organic acid or carbonic acid which becomes a counter anion of iron (II) ion can be used. The inventors examined a method for dissolving nickel in formic acid. As a result, by adding a small amount of formic acid to solid nickel formate, nickel formate is completely dissolved, and a drug (second drug) containing nickel (II) ions that can be used to form a nickel ferrite film can be obtained. It was.

  In this embodiment, the first connection point (connection point between the injection pipe 74 and the circulation pipe 35) 77 to the circulation pipe 35 of the pH adjusting agent injection device 87 and the first connection point to the circulation pipe 35 of the iron (II) ion implantation apparatus 85 are used. 2 connection points (connection point between the injection pipe 72 and the circulation pipe 35) 78, a third connection point (connection point between the injection pipe 83 and the circulation pipe 35) 84 to the circulation pipe 35 of the nickel ion implantation apparatus 88, and an oxidant injection apparatus. Of the fourth connection points (connection points between the injection pipe 73 and the circulation pipe 35) 79 to the circulation pipe 35 of 86, the first connection point 77 is located on the most downstream side. The other connection points are arranged in the order of the third connection point 84, the second connection point 78, and the fourth connection point 79 upstream from the first connection point 77, that is, toward the circulation pump 32. The first connection point 77 is preferably located in the circulation pipe 35 as close as possible to the target site for chemical decontamination and nickel ferrite film formation. A pipe 75 provided with a valve 54 communicates the pipe 73 and the pipe 69. A pH meter 76 is installed in the circulation pipe 35 downstream of the first connection point 77. Before each medicine is injected into the circulation pipe 35, the surge tank 31 is filled with water used for processing. In order to remove oxygen contained in the aqueous solution, it is preferable to bubble an inert gas such as nitrogen or argon into the chemical tank 45 and the surge tank 31.

  The decomposition device 64 can decompose an organic acid (for example, formic acid) used as a counter anion of iron (II) ions and a hydrazine as a pH adjusting agent. That is, as a counter anion of iron (II) ion, an organic acid that can be decomposed into water and carbon dioxide in consideration of reduction of the amount of waste, or carbonic acid that can be released as a gas and does not increase waste is used.

The method for forming a nickel ferrite film in the present embodiment will be described in detail with reference to FIG.
The procedure shown in FIG. 1 includes not only the formation of a nickel ferrite film, but also a chemical decontamination process and a treatment process of a film-forming aqueous solution used for forming the nickel ferrite film. First, the film forming apparatus 30 is connected to the piping system to be coated (Step S1). That is, in the operation stop period of the BWR plant after the operation of the BWR plant is stopped for the periodic inspection of the BWR plant, as described above, the circulation pipe 35 is connected to the water supply pipe 10 which is a pipe system to which a film is formed. Is done.

  Chemical decontamination is performed on the film formation target portion (step S2). An oxide film is formed on the inner surface of the water supply pipe 10 in contact with the water supply. In the BWR plant, this oxide film contains a radionuclide. An example of step S2 is a process of removing the oxide film from the inner surface of the water supply pipe 10 which is a film formation target part by a chemical process. The formation of the nickel ferrite film on the piping system to be coated is intended to suppress corrosion of the inner surface of the water supply pipe, but the inner surface of the water supply pipe 10 is subjected to chemical decontamination in advance. It is preferable to keep it. Since it is sufficient that the surface of the carbon steel member to be coated is exposed before the nickel ferrite film is formed, it is possible to apply mechanical decontamination treatment instead of chemical decontamination.

  The chemical decontamination applied in step S2 is a known method (see Japanese Patent Laid-Open No. 2000-105295), but will be briefly described. First, the valves 34, 33, 57, 56, 55, 49 and 47 are opened, and the circulation pumps 32 and 48 are driven with the other valves closed. Thereby, the water in the surge tank 31 is circulated in the water supply pipe 10. The circulating water is heated by the heater 53, and the valve 36 is opened when the temperature of the water reaches 90 ° C. A necessary amount of potassium permanganate supplied from a hopper connected to the ejector 37 is guided into the surge tank 31 by water flowing in the pipe 70. Potassium permanganate is dissolved in water in the surge tank 31, and an oxidative decontamination solution (potassium permanganate aqueous solution) is generated. The oxidative decontamination liquid is supplied from the surge tank 31 through the circulation pipe 35 into the water supply pipe 10 by driving the circulation pump 32. The oxidative decontamination solution oxidizes and dissolves contaminants such as an oxide film formed on the inner surface of the water supply pipe 10.

After the oxidative decontamination is completed, oxalic acid is injected into the surge tank 31 from the hopper.
This oxalic acid decomposes potassium permanganate contained in the oxidative decontamination solution. Thereafter, the reductive decontamination liquid (oxalic acid aqueous solution) generated in the surge tank 31 and adjusted in pH is supplied into the water supply pipe 10 by the circulation pump 32, and the corrosion products present on the inner surface of the water supply pipe 10. Perform reductive dissolution. The pH of the reductive decontamination liquid is adjusted by hydrazine supplied from the chemical liquid tank 40 into the circulation pipe 35. A part of the reductive decontamination liquid discharged from the water supply pipe 10 and returned to the circulation pipe 35 is guided to the cation exchange resin tower 60 by a necessary valve operation in order to remove metal cations.

  After completion of the reductive decontamination, the valve 65 is opened to adjust the opening degree of the valve 57, and a part of the reductive decontamination liquid flowing in the circulation pipe 35 is supplied to the decomposition device 64. Oxalic acid and hydrazine contained in the reductive decontamination solution are decomposed by the action of hydrogen peroxide introduced from the chemical solution tank 46 to the decomposition device 64 through the pipe 75 and the activated carbon catalyst in the decomposition device 64. After decomposition of oxalic acid and hydrazine, the valve 55 is closed to stop the heating by the heater 53, and at the same time, the valve 59 is opened to cool the decontamination solution by the cooler 58. The cooled decontamination liquid (for example, 60 ° C.) is supplied to the mixed bed resin tower 62 in order to remove impurities.

In the case where a nickel ferrite film is formed in piping (new water supply piping or the like) of a new plant, for example, a new BWR plant, it is not necessary to perform the chemical decontamination process in step S2.
The chemical decontamination step in step S2 is performed when a nickel ferrite film is formed in the existing BWR plant piping (water supply piping or the like).

  After the chemical decontamination of the carbon steel member is completed, a nickel ferrite film forming process is performed.

  After the decontamination of the film forming target portion is completed, the temperature of the film forming aqueous solution is adjusted (step S3). After the decontamination of the film formation target portion, that is, after the final purification operation by the film forming apparatus 30 is completed, the following valve operation is performed. The valve 50 is opened, the valve 49 is closed, and water flow to the filter 51 is started. By opening the valve 56 and closing the valve 63, water flow to the mixed bed resin tower 62 is stopped. Further, the valve 55 is opened and the water in the circulation pipe 35 is heated to a predetermined temperature by the heater 53. Valves 47, 57, 33 and 34 are open and valves 36, 59, 61, 65, 38, 41, 42 and 54 are closed. The flow of water through the filter 51 is to remove fine solids remaining in the water, and to prevent the use of chemicals due to the formation of a ferrite film on the surface of the solids. In addition, when supplying the film-forming aqueous solution to the filter 51 during chemical cleaning, it is appropriate because the pressure loss of the filter may increase due to hydroxide resulting from high-concentration iron generated by dissolution. Absent.

  The temperature of the film-forming aqueous solution is preferably maintained at about 75 ° C. while the film is formed on the inner surface of the water supply pipe 10, but is not limited to this temperature. The point is that the film structure such as crystals of the formed nickel ferrite film can be formed densely enough to suppress the corrosion of the carbon steel member during the operation of the nuclear reactor. Therefore, the temperature of the film-forming aqueous solution is preferably equal to or lower than the maximum operating temperature of the water supply pipe 10, that is, 200 ° C. or lower. The temperature of the film-forming aqueous solution is preferably at least 200 ° C. and the lower limit may be 20 ° C., but preferably 60 ° C. or more, at which the nickel ferrite film formation rate is within the practical range. When the temperature is 100 ° C. or higher, pressure must be applied in order to suppress boiling of the film-forming aqueous solution, and the pressure resistance of the temporary equipment is required. Therefore, the temperature of the aqueous solution for film formation in the film formation treatment is more preferably 100 ° C. or lower, and it is desirable to control the temperature within the range of 60 ° C. or higher and 100 ° C. or lower.

  In order not to oxidize iron (II) ions contained in the first agent to produce ferric hydroxide, it is necessary to remove dissolved oxygen in the film-forming aqueous solution. For this reason, it is preferable to perform bubbling of inert gas or vacuum deaeration in the surge tank 31 and the chemical solution tank 45.

  A drug (second drug) containing nickel ions is injected into the film-forming aqueous solution (step S4). By opening the valve 82 and driving the injection pump 81, a chemical solution (second chemical) containing nickel ions and formic acid flows from the chemical solution tank 80 through the injection pipe 83 into the circulation pipe 35 (for example, 75). ° C) in a film-forming aqueous solution (water when the second drug is injected for the first time). For example, an aqueous solution containing nickel ions and formic acid, which is a film-forming aqueous solution having a pH of 4.0, is supplied into the water supply pipe 10 through the circulation pipe 35. This aqueous solution discharged from the water supply pipe 10 is returned to the recirculation pipe 35.

When this aqueous solution contacts the inner surface of the water supply pipe 10, iron contained in the base material of the water supply pipe (carbon steel member) 10 from the inner surface of the water supply pipe 10 by the action of formic acid contained in the aqueous solution is iron (II). It becomes ions and elutes in the aqueous solution. When iron (II) ions are eluted, electrons (2e ⁻ ) are emitted. Nickel ions contained in the aqueous solution and present near the inner surface of the water supply pipe 10 capture the electrons to become nickel metal, and the nickel metal adheres to the inner surface of the water supply pipe 10 that contacts the aqueous solution. That is, since the nickel ion contained in the aqueous solution has a smaller ionization tendency than the iron (II) ion eluted from the water supply pipe 10, it becomes nickel metal by the reaction of the formula (1), and this nickel metal becomes the inner surface of the water supply pipe 10. Adhere to. Eventually, a nickel metal film as an anticorrosion film is formed over the entire area of the inner surface of the water supply pipe 10 where the aqueous solution containing nickel ions and formic acid comes into contact. Nickel metal adheres to the inner surface of the water supply pipe 10 while iron (II) ions are eluted from the water supply pipe 10 into the aqueous solution. When a nickel metal film is formed on the entire inner surface of the pipe 10 where the aqueous solution containing nickel ions and formic acid comes into contact, the nickel metal film prevents the elution of iron (II) ions from the water supply pipe 10 into the aqueous solution. Therefore, the adhesion of nickel metal to the inner surface of the water supply pipe 10 is stopped. The injection of the chemical solution containing nickel ions and formic acid into the film-forming aqueous solution is continuously performed until the formation of the nickel metal film is completed.

  A chemical solution (first drug) containing iron (II) ions is injected into the film-forming aqueous solution (step S5). The valve 41 is opened to drive the injection pump 43, and the chemical liquid (first chemical) containing iron (II) ions and formic acid is discharged from the chemical liquid tank 45 through the injection pipe 72 and nickel ions flowing in the circulation pipe 35. Inject into the film-forming aqueous solution. The first drug to be injected here contains, for example, iron (II) ions prepared by dissolving iron with formic acid and this formic acid. Part of the implanted iron (II) ions becomes ferrous hydroxide in the film-forming aqueous solution. It is desirable to add the first chemical immediately after the nickel metal film is formed on the inner surface of the water supply pipe 10 (the surface in contact with the water supply of the carbon steel member). The nickel metal film is formed on the entire inner surface of the water supply pipe 10 in contact with the film-forming aqueous solution. Formation of the nickel metal film is confirmed by measuring the corrosion current of the water supply pipe 10. When the nickel metal film is formed on the inner surface of the water supply pipe 10, the corrosion current of the water supply pipe 10 decreases. The formation of the nickel metal film can be confirmed by the decrease in the corrosion current. Alternatively, the first drug may be injected when the elapsed time after the start of injection of the drug containing nickel ions has passed a set time (for example, 5 minutes). This set time is obtained in advance by an experiment or the like as the time required to complete the formation of the nickel metal film. The start of the injection of the first drug may be at a time other than when the nickel metal film is formed on the entire inner surface of the water supply pipe 10 in contact with the aqueous solution, as long as it is after the injection of the second drug.

  An oxidizing agent is injected into the film-forming aqueous solution (step S6). The valve 42 is opened to drive the injection pump 44, and the hydrogen peroxide, which is an oxidant, flows from the chemical solution tank 46 through the injection pipe 73 into the circulation pipe 35 through the nickel ion, iron (II) ion, and hydroxylation. Pour into a film-forming aqueous solution containing ferrous iron. As the oxidizing agent, in addition to hydrogen peroxide, a chemical in which ozone or oxygen is dissolved may be used.

  A pH adjuster (fourth drug) is injected into the film-forming aqueous solution (step S7). By opening the valve 38 and driving the injection pump 39, a pH adjuster (for example, hydrazine) is injected from the chemical solution tank 40 into the film-forming aqueous solution flowing through the circulation pipe 35 through the injection pipe 74. The pH meter 76 measures the pH of the film-forming aqueous solution flowing through the circulation pipe 35. A control device (not shown) controls the rotational speed of the injection pump 39 (or the opening of the valve 38) based on the measured pH value to adjust the injection amount of hydrazine, thereby adjusting the pH of the film-forming aqueous solution to 5. Within the range of 0.5 or more and 9.0 or less, for example, it is adjusted to 7.0. That is, the pH of the film-forming aqueous solution containing hydrazine, iron (II) ions, nickel ions, ferrous hydroxide, formic acid and hydrogen peroxide is adjusted to 7.0.

  A film-forming aqueous solution containing nickel ions, iron (II) ions, ferrous hydroxide and hydrogen peroxide adjusted to 7.0 within a range of pH 5.5 to 9.0, for example. Since it flows through the water supply pipe 10, nickel ions, iron (II) ions adsorbed on the surface of the nickel metal film formed on the inner surface of the water supply pipe 10, which is a carbon steel member (the surface in contact with the film-forming aqueous solution), and Ferrous hydroxide is converted to nickel ferrite. Thereby, a nickel ferrite film is formed on the surface of the nickel metal film. Hydrogen peroxide, which is an oxidizing agent contained in the film-forming aqueous solution, causes a reaction to oxidize iron (II) ions and ferrous hydroxide, which are contained in the film-forming aqueous solution, to form nickel ferrite. Since the pH of the film-forming aqueous solution is adjusted to 7.0 within the range of 5.5 to 9.0 that causes the nickel ferrite film formation reaction to proceed with hydrazine, as described above, the surface of the nickel metal film has nickel ferrite. A film is formed.

  Since the circulation pumps 32 and 48 are driven, a film-forming aqueous solution containing hydrazine, nickel ions, iron (II) ions, ferrous hydroxide and hydrogen peroxide is passed through the on-off valve 34 by the circulation pipe 35. It is supplied into the water supply pipe 10. This film-forming aqueous solution flows through the water supply pipe 10 and is returned to the valve 47 side of the circulation pipe 35. Chemical solution containing iron (II) ions and formic acid (first drug), chemical solution containing nickel ions and formic acid (second drug), hydrogen peroxide (third drug) and hydrazine (fourth drug) ) Is injected, and this film-forming aqueous solution is introduced into the water supply pipe 10 again. Nickel formed on the inner surface of the water supply pipe 10 in which nickel ions, iron (II) ions and ferrous hydroxide are carbon steel members when the film-forming aqueous solution (film-forming liquid) contacts the inner surface of the water supply pipe 10 Since the nickel ions, iron (II) ions and ferrous hydroxide adsorbed on the surface of the metal film are converted to nickel ferrite by hydrogen peroxide, and the pH is adjusted to 7.0 by the action of hydrazine. A ferrite film mainly composed of nickel ferrite (nickel ferrite film) is formed on the inner surface of the water supply pipe 10 on the surface of the nickel metal film.

  After the nickel metal film is formed on the surface of the carbon steel member by carrying out step S4, the chemical solution containing iron (II) ions (first drug), hydrogen peroxide (third drug), and hydrazine (fourth drug) ) Is injected into a film-forming aqueous solution containing nickel ions. In particular, after the formation of the nickel metal film, it is preferable to continuously inject each agent in steps S5, S6, and S7. More specifically, after the nickel metal film is formed on the surface of the carbon steel member, when the film-forming aqueous solution in which the oxidizing agent is injected at the fourth connection point 79 reaches the second connection point 78, iron (II) A chemical solution containing ions is injected. When the film-forming aqueous solution containing these oxidizing agents and iron (II) ions reaches the third connection point 84, a chemical solution containing nickel ions is injected. When the film-forming aqueous solution containing these oxidizing agents, iron (II) ions, and nickel ions reaches the first connection point 77, the pH adjusting agent is injected into the film-forming aqueous solution.

  In order to prevent the formation of a useless nickel ferrite film on the inner surface of the circulation pipe 35, the injection point of the pH adjusting agent into the circulation pipe 35 is a position close to the water supply pipe 10 where the film is formed, that is, the on-off valve 34 and A position close to the connection point of the circulation pipe 35 is preferable.

  It is determined whether the formation process of the nickel ferrite film has been completed (step S8). This determination is made at the elapsed time after the start of the nickel ferrite film forming process, that is, the injection of the first agent and the injection of the oxidizing agent and the pH adjusting agent. Until this elapsed time reaches the time required to form a nickel ferrite film having a predetermined thickness on the inner surface of the water supply pipe 10, the determination in step S8 is “NO”. The operations in steps S4 to S7 are repeated. When the determination in step S8 is “YES”, the control device (not shown) stops the infusion pumps 39, 43, 44, and 81 (or closes the valves 38, 41, 42, and 82), and each medicine. The injection into the circulating film-forming aqueous solution is stopped. Thereby, the formation work of the nickel ferrite film on the inner surface of the water supply pipe 10 is completed.

  A chemical solution containing iron (II) ions (first drug), a chemical solution containing nickel ions (second drug), hydrogen peroxide (third drug), and hydrazine (fourth drug) into a film-forming aqueous solution The injection is continued until a nickel ferrite film having a set thickness is formed.

  Then, decomposition | disassembly of the chemical | medical agent contained in film formation aqueous solution is implemented (step S9). The film-forming aqueous solution used for forming the nickel ferrite film on the inner surface of the water supply pipe 10 contains hydrazine and formic acid, which is an organic acid, even after the formation of the nickel ferrite film is completed. Hydrazine and formic acid contained in the film-forming aqueous solution are decomposed by the decomposition apparatus 64 in the same manner as oxalic acid, which is a reducing decontamination agent. In the chemical decomposition treatment, the opening degree of the valves 57 and 65 is adjusted, and a part of the film-forming aqueous solution in the circulation pipe 35 is supplied to the decomposition device 64. By opening the valve 54, hydrogen peroxide is supplied from the chemical tank 46 through the pipe 75 to the decomposition device 64. Hydrazine and formic acid are decomposed in the decomposition apparatus 64 by the action of hydrogen peroxide and activated carbon catalyst. Hydrazine decomposes into nitrogen and water, and formic acid decomposes into carbon dioxide and water. After the decomposition of the chemical contained in the film-forming aqueous solution is completed, the circulation pipe 35 is removed from the water supply pipe 10, and the valve 28 and the like are restored to the original state. Thereby, the operation of the BWR plant can be started.

  It is also possible to use an ultraviolet irradiation device instead of the decomposition processing device 64 using a catalyst. An ultraviolet irradiation device can also decompose hydrazine, formic acid and oxalic acid in the presence of an oxidizing agent.

  By decomposing hydrazine and formic acid into gas and water in the decomposition device 64 as described above, removal of hydrazine and formic acid by the mixed bed resin tower 62 by the cation exchange resin tower 60 can be avoided. The amount of used ion exchange resin can be significantly reduced.

  In this embodiment, after the nickel metal film is formed on the entire inner surface of the water supply pipe 10 where the drug containing nickel ions contacts the film forming aqueous solution, the chemical liquid containing iron (II) ions is injected into the film forming aqueous solution. doing. For this reason, in this embodiment, the pH of the film-forming aqueous solution supplied into the water supply pipe 10 is influenced by the formic acid contained in the first drug after the injection of the first drug before the injection of hydrazine. Even if it becomes 0.0, since the nickel metal film is formed on the carbon steel member surface, corrosion of the inner surface of the water supply pipe 10, that is, the surface of the carbon steel member can be suppressed.

  In this embodiment, the corrosion of the inner surface of the water supply pipe 10 can be suppressed by the nickel metal film at the time of forming the nickel ferrite film, so that iron (II) ions and nickel ions are the inner surface of the water supply pipe 10, specifically nickel. It becomes easy to adhere to the surface of the metal film. For this reason, the time required for forming the nickel ferrite film having the set thickness on the inner surface of the water supply pipe 10 can be further shortened. In this embodiment, the total time obtained by adding the time required for forming the nickel metal film to the time required for forming the nickel ferrite film is the same as that disclosed in JP-A-2007-182604. The time required for forming a nickel ferrite film having a set thickness by the method is shortened.

  The nickel ferrite film is denser than the nickel metal film, and the corrosion protection effect of the carbon steel member is greater than that of the nickel metal film. The present embodiment in which the nickel ferrite film and the nickel metal film, which are two anticorrosion films, are formed on the inner surface of the water supply pipe 10, significantly suppresses corrosion of the inner surface of the water supply pipe 10 that is a carbon steel member during operation of the BWR plant. be able to. In particular, since the nickel ferrite film covers the nickel metal film, the corrosion can be further reduced.

The iron (II) ions eluted from the water supply pipe 10 to the film-forming aqueous solution during the formation of the nickel metal film are used to form a nickel ferrite film on the surface of the nickel metal film.
For this reason, at the time of nickel ferrite film formation, the quantity of the chemical | medical solution containing iron (II) ion and formic acid inject | poured into the film formation aqueous solution which is flowing in the circulation piping 35 with the iron (II) ion implantation apparatus 85 can be reduced.

  In this example, the nickel metal film is formed so that the nickel ferrite film is thicker than when the nickel metal film is not formed. For this reason, according to the present Example, corrosion of the feed water piping 10 which is a carbon steel member can further be reduced.

  In this example, the same kind of hydrogen peroxide is used as the oxidizing agent necessary for forming the nickel ferrite film and the oxidizing agent used when decomposing hydrazine and formic acid contained in the aqueous solution for forming the film. The chemical liquid tank 46 to be filled and the infusion pump 44 for transferring it can be shared. For this reason, the structure of the film forming apparatus 30 can be simplified.

  In this embodiment, since a chemical containing chlorine is not used as the chemical used for forming the nickel ferrite film, the soundness (for example, corrosion resistance) of the constituent members of the BWR plant is not impaired. In order to suppress the amount of drug used, it is preferable to separate and remove excess reaction products, collect unreacted drug, and reuse the unreacted drug after recovery.

  When a chemical solution containing iron (II) ions and formic acid is injected into the film forming aqueous solution containing nickel ions before the nickel metal film is formed on the entire inner surface of the water supply pipe 10 in contact with the film forming aqueous solution, Hydrogen peroxide (third drug) and hydrazine (fourth drug) are injected after the nickel metal film is formed on the entire inner surface.

In this case, before the nickel metal film is formed on the entire inner surface of the water supply pipe 10 in contact with the film forming aqueous solution, the film forming aqueous solution containing nickel ions and iron (II) ions is supplied into the water supply pipe 10. There is a period to be played. During this period, a chemical solution containing nickel ions and formic acid (second drug) and a chemical solution containing iron (II) ions and formic acid (first drug) are injected, respectively, but the pH of the film-forming aqueous solution is 4.0. is there. If, when the p H is less than 4.0, it is adjusted to 4.0 pH by injecting hydrazine. Even when a chemical solution containing iron (II) ions and formic acid is injected into the film forming aqueous solution containing nickel ions before the nickel metal film is formed on the entire inner surface of the water supply pipe 10 in contact with the film forming aqueous solution, Electrons (2e ⁻ ) generated when iron (II) ions are eluted from the inner surface of the water supply pipe 10 are captured by nickel ions in the film-forming aqueous solution, and nickel metal is generated. The nickel metal adheres to the inner surface of the water supply pipe 10 that contacts the aqueous solution, and a nickel metal film is formed on the inner surface of the water supply pipe 10.

  A method for forming a nickel ferrite film on a carbon steel member of Example 2 applied to a water supply pipe of a BWR plant, which is another example of the present invention, will be described with reference to FIG. In this embodiment, a nickel metal film and a nickel ferrite film are formed on the inner surface of the water supply pipe 10 by using the film forming apparatus 30A shown in FIG. 9 instead of the film forming apparatus 30 used in the first embodiment.

  The film forming apparatus 30 </ b> A is provided with an implantation apparatus 89 that combines the iron (II) ion implantation apparatus 85 and the nickel ion implantation apparatus 88 in the film formation apparatus 30. Other configurations of the film forming apparatus 30A are the same as those of the film forming apparatus 30. The injection device 89 includes a chemical tank 90, an injection pump 91, and an injection pipe 93. The chemical tank 90 is connected to the circulation pipe 35 by an injection pipe 93 having an injection pump 91 and a valve 92. A connection point 94 between the injection pipe 93 and the circulation pipe 35 is disposed between the first connection point 77 and the fourth connection point 79. The chemical solution tank 90 is provided with a nitrogen gas or inert gas bubbling device (or a device for exhausting the chemical solution tank 90) in order to prevent the oxidation of the chemical agent.

  In this example, in a non-radiation control area (for example, a factory) outside the radiation control area, a chemical solution containing iron (II) ions and formic acid (first drug) and a chemical solution containing nickel ions and formic acid (second drug) Are prepared, and these chemical solutions are mixed in advance to produce a new chemical solution (fifth drug) containing iron (II) ions, nickel ions and formic acid. The transport container storing the chemical solution is transported to the turbine building where the film forming apparatus 30A is disposed. Similar to the first embodiment, both ends of the circulation pipe 35 of the film forming apparatus 30A are connected to the water supply pipe 10 to be coated. A chemical solution containing iron (II) ions, nickel ions and formic acid conveyed in the conveyance container is filled in the chemical solution tank 90.

  A method for forming a nickel ferrite film on the carbon steel member of this example using the film forming apparatus 30A will be described. In this embodiment, the operations of Steps S1 to S3 and Steps S6 to S9 shown in FIG. 1 are performed, and iron (II) ions, nickel ions, and formic acid in the chemical tank 90 are added between Steps S3 and S6. The contained chemical solution is injected into the circulation pipe 35. The injection of the chemical solution (fifth drug) is performed by opening the valve 92 and driving the injection pump 91 after the operation of step S3 is completed. When the injection pump 91 is driven, a chemical solution containing iron (II) ions, nickel ions and formic acid flows from the chemical solution tank 90 through the injection pipe 83 through the circulation pipe 35 at a predetermined temperature (for example, 75 ° C.). (When the fifth medicine is injected for the first time, inject water). This aqueous film-forming solution containing iron (II) ions, nickel ions and formic acid is supplied through the circulation pipe 35 into the film-forming location of the water supply pipe 10. Similar to the first embodiment, a nickel metal film is formed on the inner surface of the water supply pipe 10. In the present embodiment, steps S4 and S5 of the first embodiment are performed simultaneously.

  Thereafter, operations in steps S6 and S7 are performed, and the film-forming aqueous solution having a pH of 7.0 containing iron (II) ions, nickel ions, and hydrogen peroxide is put in the water supply pipe 10 as in the first embodiment. Supplied. For this reason, a nickel ferrite film is formed on the surface of the nickel metal film formed in the water supply pipe 10. In this embodiment, after the nickel metal film is formed on the entire inner surface of the water supply pipe 10 that is in contact with the film forming aqueous solution, the oxidizing agent and the pH adjuster are added to the film forming aqueous solution. A two-layer anticorrosion film including a nickel metal film and a nickel ferrite film can be formed on the inner surface.

  In the present embodiment, each effect produced in the first embodiment can be obtained. Since the present embodiment uses an injection device 89 for injecting iron (II) ions and nickel ions, the configuration of the film forming apparatus 30A can be simplified compared to the film forming apparatus 30, and the film forming procedure is also the same as in the first embodiment. Than can be simplified.

  A nickel ferrite film forming method on a carbon steel member of Example 3 applied to a water supply pipe of a BWR plant, which is another example of the present invention, will be described with reference to FIGS. The above-mentioned method C is applied to the nickel ferrite film forming method of this example. In this example, first, the corrosion of the carbon steel member during the formation of nickel ferrite is reduced by controlling the pH of the aqueous solution for film formation to a pH value in the range of more than 6.0 and 9.0 or less. Example 1 and 2 are different in that a nickel ferrite film is formed.

  The film forming apparatus 30B used in the present embodiment has the same components as the film forming apparatus 30 used in the first embodiment, but includes an iron (II) ion implantation apparatus 85, an oxidant implantation apparatus 86, and a pH. The position of each connection point with respect to the circulation pipe 35 of the adjusting agent injection device 87 and the nickel ion implantation device 88 is different. That is, the 1st connection point 77, the 2nd connection point 78, the 3rd connection point 84, and the 4th connection point 79 are arrange | positioned toward the on-off valve 34 from the circulation pump 32 in this order. When the pH adjusting agent is injected into the aqueous solution for film formation prior to the oxidizing agent, the fourth connection point 79 of the nickel ion implanter 88 may be disposed at a position close to the water supply pipe 10 that is a film formation countermeasure location. preferable.

  When carrying out the method of forming the nickel ferrite film on the carbon steel member of the present embodiment using the film forming apparatus 30B, both ends of the circulation pipe 35 of the film forming apparatus 30B are in the period of stopping the operation of the BWR plant as in the first embodiment. And connected to the water supply pipe 10. The nickel ferrite film forming method of the present embodiment implements steps S1 to S3 performed in the first embodiment. After step S3 is completed, a pH adjuster (fourth drug) is injected into the film-forming aqueous solution (step S4). Similarly to step S7 of the first embodiment, the valve 38 is opened and the injection pump 39 is driven, so that the pH adjusting agent (for example, hydrazine) flows from the chemical solution tank 40 through the injection pipe 74 through the circulation pipe 35. Injected into a film-forming aqueous solution (water when the fourth drug is injected for the first time). The pH of the film-forming aqueous solution flowing through the circulation pipe 35 is measured by a pH meter 76. A control device (not shown) controls the rotational speed of the injection pump 39 (or the opening of the valve 38) based on the measured pH value to adjust the injection amount of hydrazine into the circulation pipe 35, thereby forming a film-forming aqueous solution. The pH is adjusted to 7.0, for example, within a range greater than 6.0 and less than or equal to 9.0.

  A chemical solution (first drug) containing iron (II) ions is injected into the film-forming aqueous solution (step S5). When the film-forming aqueous solution whose pH is adjusted to 7.0 flows through the second connection point 78, a chemical solution containing iron (II) ions and formic acid (first drug) is the same as in Step S5 of Example 1. Is injected from the iron (II) ion implantation apparatus 85 into the film-forming aqueous solution. A drug containing nickel ions (second drug) is injected into the film-forming aqueous solution (step S6). When the pH is adjusted to 7.0 and the film-forming aqueous solution containing iron (II) ions flows through the third connection point 84, the chemical solution containing nickel ions and formic acid (step S4 in Example 1) The second drug) is injected from the nickel ion implanter 88 into the film-forming aqueous solution. An oxidizing agent is injected into the film-forming aqueous solution (step S7). When the pH is adjusted to 7.0 and the film-forming aqueous solution containing iron (II) ions and nickel ions flows through the fourth connection point 79, hydrogen peroxide (second step) is obtained as in step S6 of Example 1. 3 chemicals) are injected into the film-forming aqueous solution from the oxidizing agent injection device 86. The pH is adjusted to 7.0, and iron (II) ions, nickel ions, and hydrogen peroxide, for example, a 75 ° C. film-forming aqueous solution is supplied from the circulation pipe 35 into the water supply pipe 10. Contact the inner surface.

  By performing the operations in steps S4 to S7, the film-forming aqueous solution containing iron (II) ions, nickel ions and hydrogen peroxide and having a pH of 7.0 is continuously supplied to the circulation pipe 35. It is supplied into the pipe 10. For this reason, a nickel ferrite film is formed over the entire inner surface of the water supply pipe 10 in contact with the film-forming aqueous solution. The nickel ferrite film is formed by adjusting the pH to 7.0 and injecting hydrogen peroxide into a film-forming aqueous solution containing iron (II) ions and nickel ions, thereby forming a nickel ferrite reaction in the water supply pipe 10. Is done by happening.

  After the operation in step S7 is completed, the determination in step S8 is performed. When this determination is “NO”, the operations in steps S4 to S8 are repeated. When the determination in step S8 is “YES”, the process in step S9 is performed, and the formation work of the nickel ferrite film on the inner surface of the water supply pipe 10 is completed. When the process of step S9 is completed, the circulation pipe 35 is removed from the water supply pipe 10 within the operation stop period of the BWR plant.

  In this example, the pH adjuster is first injected into the film-forming aqueous solution, and the pH of the film-forming aqueous solution is adjusted to a pH value within the range of more than 6.0 and 9.0 or less. The film-forming aqueous solution containing iron (II) ions and formic acid without pH and having a pH of 4.0 can be prevented from coming into contact with the inner surface of the water supply pipe 10. For this reason, when the nickel ferrite film is formed on the inner surface of the water supply pipe 10, the elution of iron (II) ions does not occur from the inner surface of the water supply pipe 10. Since this elution of iron (II) ions does not occur, the nickel ferrite generated on the inner surface of the water supply pipe 10 by the nickel ferrite reaction is firmly attached to the inner surface of the water supply pipe 10. Therefore, the time required to form the nickel ferrite film having the set thickness on the inner surface of the water supply pipe 10 is shortened.

  The order of injecting the other chemicals into the film-forming aqueous solution after injecting the pH adjuster for the first time may be any injection order.

  A liquid whose pH is adjusted to a pH value greater than 6.0 and less than or equal to 9.0 by adding a pH adjuster is supplied into the water supply pipe 35 through the circulation pipe 35, and then iron (II ) Even if a liquid containing ions, nickel ions, and hydrogen peroxide and having a pH of 7.0 is supplied into the water supply pipe 10, the above-described effects can be obtained.

  The nickel ferrite film forming method on the carbon steel member of Example 4 applied to the purification system piping 20 of the BWR plant, which is another example of the present invention, will be described below with reference to FIG. Corrosion becomes a problem in the reactor purification system in the regenerative heat exchanger 25 into which high-temperature cooling water from the RPV 12 flows. Valves 96 and 97 are provided in the purification system pipe 20 upstream and downstream of the regenerative heat exchanger 25 made of carbon steel.

  Within the period of shutdown of the BWR plant, the bonnet of the valve 96 is opened and one end of the circulation pipe 35 of the film forming apparatus 30 is connected to the flange of the bonnet where the valve 96 is opened. The valve 23 provided in the purification system pipe 20 is closed. The bonnet of the valve 97 is opened to seal the flange on the non-regenerative heat exchanger 26 side. The other end of the circulation pipe 35 of the film forming apparatus 30 is connected to the flange of the bonnet where the valve 97 is opened. In this way, the film forming apparatus 30 is connected to the purification system pipe 20, and a circulation path of the film forming aqueous solution is formed by the purification system pipe 20 and the circulation pipe 35.

  Also in the present embodiment, the operations and processes of steps S1 to S9 in the first embodiment are executed. As a result, a nickel metal film is formed on the inner surface (the inner surface of the shell) of the non-regenerative heat exchanger 25 in contact with the film-forming aqueous solution, as in Example 1, and the nickel ferrite film is formed on the surface of the nickel metal film. It is formed. After the process of step S9 is completed, and within the operation stop period of the BWR plant, the circulation pipe 35 is removed from the purification system pipe 20.

  Also in this embodiment, each effect produced in the first embodiment can be obtained.

  When the valve 87 does not exist between the regenerative heat exchanger 25 and the non-regenerative heat exchanger 26, an isolation valve provided in the purification system pipe 20 between the non-regenerative heat exchanger 26 and the reactor water purification device 27 is provided. The other end of the circulation pipe 35 of the film forming apparatus 30 may be connected.

  In this embodiment, instead of the film forming apparatus 30, the above-described film forming apparatus 30A or 30B may be used. When the film forming apparatus 30B is used, each operation of steps S1 to S19 shown in FIG. 10 is executed, and each effect produced in the third embodiment can be obtained.

  Any one of the film forming devices 30, 30A and 30B is a carbon steel member in a BWR plant, for example, a residual heat removal system pipe, a reactor isolation cooling system pipe, a core spray system pipe, an auxiliary machine cooling water The nickel ferrite film forming method according to any one of the first, second, and third embodiments may be applied by connecting to the piping of the system and the piping of the cooling water system using the cooling tower.

  Further, the nickel ferrite film forming method on the carbon steel members of Examples 1, 2 and 3 is applied not only to the BWR plant but also to the carbon steel water supply pipe of the PWR plant and the carbon steel water supply pipe of the thermal power plant. be able to. At this time, any one of the film forming apparatuses 30, 30A, and 30B is connected to the water supply pipe of the corresponding plant.

  A method for forming a nickel ferrite film on a carbon steel member of Example 5 applied to a water supply pipe of a BWR plant, which is another example of the present invention, will be described with reference to FIG. In this embodiment, a nickel metal film and a nickel ferrite film are formed on the inner surface of the water supply pipe 10 using the film forming apparatus 30 used in the first embodiment.

  The nickel ferrite film forming method of this embodiment is obtained by adding “injection of pH adjusting agent” in step S10 to the steps S1 to S9 performed in the first embodiment. The process of step S10 is performed between step S4 and step S5 in the first embodiment.

  While the temperature of the film-forming aqueous solution supplied from the circulation pipe 35 to the water supply pipe 10 to which the circulation pipe 35 is connected is heated to 75 ° C. and a film is formed on the inner surface of the water supply pipe 10 in step S3, Held at temperature. In step S4, a film-forming aqueous solution (second drug) at a predetermined temperature (for example, 75 ° C.) in which a chemical solution (second drug) containing nickel ions and formic acid flows through the circulation pipe 35 from the chemical liquid tank 80 through the injection pipe 83. Is first injected into the water). Thereafter, a pH adjuster (fourth drug) is injected into the film-forming aqueous solution (step S10). By opening the valve 38 and driving the injection pump 39, a pH adjuster (for example, hydrazine) is injected from the chemical solution tank 40 into the film-forming aqueous solution flowing through the circulation pipe 35 through the injection pipe 74. The pH meter 76 measures the pH of the film-forming aqueous solution flowing through the circulation pipe 35. A control device (not shown) controls the rotational speed of the injection pump 39 (or the opening degree of the valve 38) based on the measured pH value to adjust the injection amount of hydrazine, thereby adjusting the pH of the film-forming aqueous solution to 4. Within the range of not less than 0.0 and not more than 9.0, for example, it is adjusted to 5.0.

  By injecting the chemical solution in steps S4 and S10, a chemical solution containing nickel ions and formic acid (second drug) and a pH 5.0 film-forming aqueous solution containing hydrazine are supplied from the circulation pipe 35 into the water supply pipe 10. By supplying the aqueous solution for forming a film, a nickel metal film is formed on the inner surface of the water supply pipe 10 by the reaction of the expression (1) as in the first embodiment.

In this example, since hydrazine is contained in the aqueous solution for forming a nickel metal film, only electrons (2e ⁻ ) emitted when iron (II) ions are eluted from the water supply pipe 10 by the action of formic acid. In addition, electrons (4e ⁻ ) generated by the oxidation reaction of hydrazine represented by the formula (3) also act, and a nickel metal film is formed on the inner surface of the water supply pipe 10.

N ₂ H ₄ + 4OH ⁻ → N ₂ + 4H ₂ O + 4e ⁻ (3)
After the nickel metal film is formed on the entire inner surface of the water supply pipe 10 in contact with the film-forming aqueous solution, a nickel ferrite film is formed on the surface of the nickel metal film. In order to form this nickel ferrite film, in the same manner as in Example 1, injection of a chemical solution (first agent) containing iron (II) ions and formic acid in Step S5, and injection of hydrogen peroxide as an oxidizing agent in Step S6 And injection of hydrazine as a pH adjusting agent in step S7 is performed. Injection of a chemical solution (second drug) containing nickel ions and formic acid from the chemical solution tank 80 is also continuously performed. The injection of hydrazine in step S7 requires the pH of the film-forming aqueous solution containing nickel ions, iron (II) ions, formic acid and hydrogen peroxide supplied to the water supply pipe 10 to be 5.5 necessary for forming the nickel ferrite film. Adjust within the range of 9.0 to, for example, 7.0. Adjustment of the pH of this film-forming aqueous solution is performed by controlling the rotational speed of the injection pump 39 (or the opening of the valve 38) based on the pH measurement value measured by the pH meter 76, and hydrazine into the circulation pipe 35. This is done by adjusting the injection amount.

  A film-forming aqueous solution containing nickel ions, iron (II) ions, formic acid and hydrogen peroxide having a pH of 7.0 is supplied from the circulation pipe 35 into the water supply pipe 10. As a result, as in Example 1, a nickel ferrite film is formed on the surface of the nickel metal film formed on the inner surface of the water supply pipe 10. Since nickel ferrite is more stable than nickel metal in an aqueous solution, a nickel ferrite film is preferentially formed after all agents are added.

  When the determination in step S8 is “YES”, the infusion pumps 39, 43, 44 and 81 are stopped, and the injection of each drug into the circulating film-forming aqueous solution is stopped. Thereby, the formation work of the nickel ferrite film on the inner surface of the water supply pipe 10 is completed. Then, the chemical | medical agent contained in the film formation aqueous solution in step S9 is performed.

  In the present embodiment, each effect produced in the first embodiment can be obtained. In this embodiment, since the film-forming aqueous solution for forming the nickel metal film contains hydrazine, electrons generated by the oxidation reaction of hydrazine of the formula (3) can be used for forming the nickel metal film. For this reason, the time required for forming the nickel metal film can be reduced as compared with the first embodiment.

  The present invention can be applied to carbon steel piping of nuclear power plants and thermal power plants.

  DESCRIPTION OF SYMBOLS 1 ... Reactor, 3 ... Turbine, 4 ... Condenser, 10 ... Feed water piping, 12 ... Reactor pressure vessel, 30, 30A, 30B ... Film formation apparatus, 31 ... Surge tank, 32, 48 ... Circulation pump, 35 ... circulation piping, 37 ... ejector, 39,43,44,81,91 ... infusion pump, 40,45,46,80,90 ... chemical tank, 51 ... filter, 53 ... heater, 58 ... cooler, 60 ... Cation exchange resin tower, 62 ... Mixed bed resin tower, 64 ... Decomposition device, 72, 73, 74, 83, 93 ... Injection pipe, 85 ... Iron (II) ion injection device, 86 ... Oxidant injection device, 87 ... pH Conditioner injection device, 88 ... Nickel ion implantation device, 89 ... Injection device.

Claims (14)

  The surface of the carbon steel member constituting the plant in contact with water is contacted with a film forming solution containing nickel ions, the pH of which is adjusted to a value within the range of 4.0 or more and 9.0 or less. On the surface of the nickel metal film formed, a first agent containing iron (II) ions, a second agent containing nickel ions, and a third agent that oxidizes the iron (II) ions, A nickel ferrite film is formed on the surface of the nickel metal film by contacting a film forming solution whose pH is adjusted to a value within the range of 5.5 to 9.0 by adding a regulator. A method for forming a nickel ferrite film on a carbon steel member. The method for forming a nickel ferrite film on a carbon steel member according to claim 1, wherein the film forming liquid for forming the nickel metal film contains a pH adjuster.   The film forming liquid for forming the nickel metal film contains iron (II) ions, and after the formation of the nickel metal film, the third agent and the pH adjuster are used to form the nickel metal film. The method for forming a nickel ferrite film on a carbon steel member according to claim 1, wherein the film forming liquid is formed by injecting into a forming liquid to form the nickel ferrite film. The film-forming solution, a nickel ferrite film formation method of the carbon steel member according to any one of claims 1 comprises formic acid 3 to form a pre-Symbol nickel metal film.   The method for forming a nickel ferrite film on a carbon steel member according to any one of claims 1 to 3, wherein the formation of the nickel metal film and the nickel ferrite film is performed within a period in which the operation of the plant is stopped. .   The temperature of the said film formation liquid which forms the said nickel ferrite film is adjusted to the temperature contained in the range of 60 to 100 degreeC, The nickel ferrite to the carbon steel member of any one of Claim 1 thru | or 4 Film formation method. In a period in which the operation of the plant is stopped, a pipe having a pump is connected to a pipe system including the carbon steel member constituting the plant,
The piping system is configured by supplying a first film forming liquid containing nickel ions, whose pH is adjusted to a value in the range of 4.0 or more and 9.0 or less, from the piping into the piping system. Forming a nickel metal film on the surface of the carbon steel member;
A first drug containing iron (II) ions, a second drug containing nickel ions, and a third drug that oxidizes the iron (II) ions, and a pH of 5.5 or more by adding a pH adjuster to 9.0 By supplying a second film forming liquid adjusted to a value included in the following range from the pipe into the pipe system, nickel ferrite is formed on the surface of the nickel metal film formed on the surface of the carbon steel member. Forming a film,
A method for forming a nickel ferrite film on a carbon steel member, wherein the piping is removed from the piping system within the period.   The first film forming liquid contains the iron (II) ions, and after the formation of the nickel metal film, the third chemical agent and the pH adjuster are injected into the first film forming liquid in the pipe. The method for forming a nickel ferrite film on a carbon steel member according to claim 7, wherein the second film forming liquid is generated in a pipe.   The carbon according to claim 7 or 8, wherein the first film forming liquid and the second film forming liquid are adjusted to a temperature within a range of 60 ° C to 100 ° C by a heating device provided in the pipe. A method for forming a nickel ferrite film on a steel member.   The both ends of the piping are connected to the piping system to form a closed loop by the piping and the piping system, and the first film forming liquid and the second film forming liquid are circulated in the closed loop. The nickel ferrite film formation method to the carbon steel member of description. A liquid containing a pH adjuster flowing in a pipe connected to a pipe system including a carbon steel member constituting a plant, a first drug containing iron (II) ions and an acid, a second drug containing nickel ions, and the above Adding a third agent that oxidizes iron (II) ions to iron (III) ions;
Iron (II) ions, contain nickel ions and the third agent, and a pH of greater than 6.0 9. A nickel ferrite film is formed on the surface by supplying the liquid adjusted to a value included in the range of 0 or less to the surface of the carbon steel member in contact with water by supplying the liquid from the piping to the piping system. A method for forming a nickel ferrite film on a carbon steel member. The first chemical containing iron (II) ions and acid, the second chemical containing nickel ions, and the iron (II) ions flowing through the piping connected to the piping system including the carbon steel member constituting the plant are converted into iron. (III) greater than pH 6.0 by the pH adjusting agent without including a third agent which is oxidized to ions 9. The first liquid adjusted to a value included in the range of 0 or less is supplied from the pipe to the pipe system and brought into contact with the surface of the carbon steel member in contact with water,
After the first liquid is in contact with said surface, in said pipe, iron (II) ions, wherein the two Kkeruion及Beauty third agent, 9.0 to a pH of greater than 6.0 by the pH adjusting agent Producing a second liquid adjusted to a value included in the range of
A method of forming a nickel ferrite film on a carbon steel member, comprising forming the nickel ferrite film on the surface by supplying the second liquid flowing in the pipe to the pipe system and bringing it into contact with the surface .   The carbon according to claim 11 or 12, wherein the temperature of the liquid forming the nickel ferrite film that is brought into contact with the surface of the carbon steel member is adjusted to a temperature within a range of 60 ° C to 100 ° C. A method for forming a nickel ferrite film on a steel member.   The method for forming a nickel ferrite film on a carbon steel member according to any one of claims 11 to 13, wherein the formation of the nickel ferrite film is performed within a period in which the operation of the plant is stopped.

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