JP5467137B2 - Method and apparatus for forming ferrite film on the surface of plant component - Google Patents

Description

  The present invention relates to a method and apparatus for forming a ferrite film on the surface of a plant component, and more particularly to formation of a ferrite film on the surface of a plant component suitable for application to a boiling water nuclear power plant. The present invention relates to a method and a ferrite film forming apparatus.

  As a nuclear power plant, for example, a boiling water nuclear power plant (hereinafter referred to as a BWR plant) and a pressurized water nuclear power plant (hereinafter referred to as a PWR plant) are known. For example, a BWR plant has a nuclear reactor with a core built in a reactor pressure vessel (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, metal impurities are mainly removed by a filtration and desalination apparatus provided in the water supply 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 in contact with water in order to suppress corrosion. In addition, components such as the reactor coolant purification system, residual heat removal system, reactor isolation cooling system, core spray system, feed water system, and condensate system are used from the viewpoint of reducing the required manufacturing cost of the plant or the feed water system and the recovery system. Carbon steel members are mainly used from the viewpoint of avoiding stress corrosion cracking of stainless steel caused by high-temperature water flowing in the water system.

  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 feed water system, and the condensate system also have a water contact portion in contact with water. The wetted parts may corrode. 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, in order to suppress the corrosion of the carbon steel member which is a constituent member of the nuclear power plant, a dense ferrite film (for example, magnetite film, nickel ferrite film) may be formed on the surface of the carbon steel member in contact with water. It has been proposed (see, for example, JP 2007-182604 A). In the formation of the ferrite film, iron (II) ions are converted into a first agent, iron (II) ions are converted into iron (II) ions, a second agent (oxidizing agent), and a third agent (pH adjusting agent) that adjusts pH. ) Is used. Since the ferrite film serves as a protective film for blocking the cooling water from coming into contact with the carbon steel member, corrosion of the surface of the member in contact with the cooling water suitable for application to a nuclear power plant is suppressed.

  The surface of the stainless steel member in contact with water in order to suppress the attachment of the radionuclide to the surface of the stainless steel member that is a component of the nuclear power plant in contact with water (for example, the inner surface of the recirculation piping of the BWR plant) Japanese Patent Application Laid-Open No. 2006-38483 discloses a method for forming a dense ferrite film. In forming the ferrite film, the film containing the first agent containing iron (II) ions, the second agent oxidizing iron (II) ions to iron (II) ions, and the third agent adjusting pH. A forming solution is used.

JP 2007-182604 A JP 2006-38483 A

  When forming a dense ferrite film on the surface of the carbon steel member and stainless steel member in contact with the cooling water, it is necessary to confirm that a ferrite film having a predetermined thickness is formed on each surface. This is important from the viewpoints of corrosion of steel and suppression of adhesion of radionuclides to stainless steel members. Japanese Unexamined Patent Application Publication Nos. 2007-182604 and 2006-38483 do not mention anything about the confirmation of the thickness of the formed ferrite film.

  In order to confirm the thickness of the ferrite film formed on the inner surface of a component of the nuclear power plant, for example, the piping, it is conceivable to use the same test piece as the material of the piping. A method for confirming the thickness of the ferrite film will be described. The test piece is disposed, for example, in a treatment liquid supply pipe of a ferrite film forming apparatus connected to a pipe where a ferrite film is to be formed through a branch pipe. Thereafter, a film forming liquid containing the first chemical, the second chemical, and the third chemical is supplied to the pipe where the ferrite film is to be formed through the treatment liquid supply pipe. Since this film forming liquid contacts not only the inner surface of the pipe on which the ferrite film is to be formed, but also the surface of the test piece, a ferrite film is also formed on the surface of the test piece. When the elapsed time after the start of the supply of the film-forming solution that has been obtained empirically for the formation of a ferrite film with a predetermined thickness is the time that has been empirically known for the formation of a ferrite film with a predetermined thickness Then, supply of the coating solution is stopped and the test piece is taken out from the branch pipe. The weight of the test piece is measured, and the thickness of the ferrite film formed on the inner surface of the pipe is estimated based on the amount of change from the weight when it is first placed in the branch pipe.

  However, the inventors have found that the following two problems arise when estimating the thickness of the ferrite film formed on the surface of the component of the nuclear power plant based on the weight change of the test piece. (1) When the formation of the ferrite film fails and when the amount of the ferrite film does not satisfy the predetermined amount, the test piece is immersed again in the film forming solution, and the film forming solution is used for forming the ferrite film. Needs to be resumed. For this reason, it is necessary to repeat a series of procedures for forming a ferrite film, and it takes time to form a ferrite film having a predetermined thickness. (2) Even when a target ferrite film having a predetermined thickness can be formed in a short time, it is necessary to supply the film forming liquid to the pipe on which the ferrite film is to be formed only for a period of time that is empirically known. In this case, the time after the ferrite film having a predetermined thickness is formed is wasted time.

  Based on the above problems, the inventors have come to the idea that it is necessary to shorten the time required for forming the ferrite film.

  An object of the present invention is to provide a method for forming a ferrite film on the surface of a plant constituent member and a ferrite film forming apparatus capable of shortening the time required for completing a ferrite film forming operation.

  The feature of the present invention that achieves the above-described object is that the amount of ferrite film formed is measured, and the amount of injection of the chemical solution containing iron (II) ions and the oxidizing agent into the film forming solution is measured. The film formation rate obtained based on the above is controlled so as to be the set formation rate, and the chemical solution containing iron (II) ions and the injection of the oxidizing agent into the film formation solution are performed based on the measured ferrite film formation amount. It is to stop.

  Based on the measured formation amount of the ferrite film, the injection amount of the chemical solution containing iron (II) ions and the oxidizing agent into the film formation solution is controlled. Thereby, a set amount of magnetite film can be formed in a shorter time.

  According to the present invention, the time required for completing the ferrite film forming operation can be shortened.

It is a flowchart which shows the procedure of the formation method of the ferrite membrane | film | coat on the surface of the nuclear power plant structural member of Example 1 applied to the recirculation system 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 formation apparatus used when implementing the formation method of the ferrite film shown in FIG. 1 to the recirculation system piping of a BWR plant. It is a detailed block diagram of the film forming apparatus shown in FIG. It is explanatory drawing which shows the detailed attachment state to the film formation liquid piping shown in FIG. 3 of the crystal oscillator electrode apparatus shown in FIG. It is a characteristic view which shows the measurement result of the weight change measured by the crystal oscillator electrode device in the state which immersed the crystal oscillator electrode device of the ready-made product in the 90 degreeC pure water. It is a longitudinal cross-sectional view of an off-the-shelf crystal resonator electrode device. It is a longitudinal cross-sectional view of the improved crystal oscillator electrode device. It is a characteristic view which shows the measurement result of the weight change measured with the crystal oscillator electrode device in the state which immersed the crystal oscillator electrode device shown in FIG. 7 in the pure water of temperature 90 degreeC. It is a characteristic view which shows the change of the weight increase of the film | membrane measured using the crystal oscillator electrode apparatus shown in FIG. 7 at the time of ferrite film formation. It is a characteristic view which shows the laser Raman spectrum of the structural member surface in which the ferrite membrane | film | coat was formed. It is a detailed block diagram of the membrane | film | coat formation apparatus used for the formation method of the ferrite membrane | film | coat on the surface of the nuclear power plant structural member of Example 2 applied to the recirculation system piping of the BWR plant which is another Example of this invention. It is a detailed block diagram of the membrane | film | coat formation apparatus used for the formation method of the ferrite membrane | film | coat on the surface of the nuclear power plant structural member of Example 3 applied to the recirculation system piping of the BWR plant which is another Example of this invention. It is a flowchart which shows the procedure of the formation method of the ferrite membrane | film | coat on the surface of the nuclear power plant structural member of Example 3 performed using the membrane | film | coat formation apparatus shown in FIG. The state which connected the film formation apparatus to purification system piping in the formation method of the ferrite film to the surface of the nuclear power plant structural member of Example 4 applied to purification system piping of the BWR plant which is another Example of this invention is shown. It is explanatory drawing.

  The inventors have studied in order to find a method for forming a ferrite film on the surface of a nuclear plant constituent member, which can shorten the time required for completing the ferrite film forming operation. The result of this examination will be described below.

  The inventors tackled the problem of whether the thickness of the ferrite film formed on the inner surface of the pipe could be measured while supplying the film forming liquid to the pipe where the ferrite film should be formed. Therefore, the technique that the inventors have paid attention to is the quartz crystal microbalance method (hereinafter referred to as QCM). QCM is a technique for continuously measuring a minute weight in an aqueous solution at 60 ° C. or lower.

  In the method of forming a ferrite film on the surface of a nuclear plant component member, the temperature of the film forming liquid supplied to the pipe on which the ferrite film is to be formed must be 60 ° C to 100 ° C. Preferably, the temperature of the film forming liquid is 90 ° C. There is no example of applying QCM to such a high-temperature liquid.

Therefore, the inventors examined the applicability of QCM in forming a ferrite film on the surface of a component of a nuclear power plant. An off-the-shelf crystal resonator electrode device to which QCM used at 60 ° C. or lower was applied was immersed in pure water at 90 ° C., and the magnitude of noise was confirmed by measurement. For this measurement, an off-the-shelf crystal resonator electrode device that guarantees a resolution of 0.15 (μg / cm ² ), which is necessary for measuring the weight change at the initial stage of ferrite film formation in detail below 60 ° C., is used. It was. FIG. 5 shows the measurement results obtained by this crystal resonator electrode device. However, the off-the-shelf crystal resonator electrode device has a large noise and cannot satisfy the required resolution.

  The inventors examined in detail the cause of the ready-made crystal resonator electrode device that produced the measurement results shown in FIG. 5 in 90 ° C. pure water. As shown in FIG. 6, the ready-made crystal resonator electrode device 16 </ b> A includes a crystal 17, a metal member 18, and an electrode holder 19. The crystal 17 is installed in the recess of the electrode holder 19, and the metal member 18 is attached to one surface that does not contact the electrode holder 19 of the crystal 17. The metal member 18 is a metal member (for example, a stainless steel member or a carbon steel member) made of the same material as the constituent members of the nuclear power plant. A seal member 20 </ b> A is installed along the inner surface of the electrode holder 19 at the periphery of this one surface of the crystal 18. The seal member 20 </ b> A prevents water (or an aqueous solution) in contact with the metal member 18 from entering between the side surface of the crystal 18 and the electrode holder 19. An annular opening 52 is formed between the seal member 20 </ b> A and the metal member 18.

  The inventors of the present invention have the characteristics shown in FIG. 5 in the pure water of 90 ° C. because the ready-made crystal resonator electrode device 16A having the above-described configuration forms the opening 52. I found out what happened. That is, in the crystal resonator electrode device 16A, since the pure water comes into contact with both the crystal 17 and the metal member 18 due to the formation of the opening 52, noise increased in 90 ° C. pure water. Based on this result, the inventors have devised a crystal resonator electrode device 16 having a new structure shown in FIG. In this improved crystal oscillator electrode device 16, the seal member 20 covers the entire surface other than the surface in contact with the metal member 18 and the electrode holder 19 in the direction of the crystal 17 installed in the recess of the electrode holder 19. It covers all over. Since the crystal resonator electrode device 16 is not formed with the opening 52 unlike the crystal resonator electrode device 16A, the crystal 17 comes into contact with water (or an aqueous solution) that contacts one surface of the metal member 18 by the seal member 20. There is nothing to do.

  The change in weight was measured by the crystal resonator electrode device 16 immersed in pure water at 90 ° C. The measurement results are shown in FIG. The measurement result of the crystal resonator electrode device 16 has a weight change substantially zero in pure water in which impurities adhering to the surface of the metal member 18 are hardly present, and is within the required resolution. The crystal resonator electrode device 16 has significantly reduced noise compared to the crystal resonator electrode device 16A, and can be measured in high-temperature 90 ° C. pure water.

  An experiment was conducted in which the amount of ferrite film formation was continuously measured using the crystal resonator electrode device 16 devised by the inventors. A stainless steel member was used as the metal member 18 of the crystal resonator electrode device 16 used in this experiment. In order to make a comparison with the amount of ferrite film formed on the surface of stainless steel, which is a component of a nuclear power plant, a stainless steel test piece (reference test piece) together with the crystal resonator electrode device 16 and the first drug, It was immersed in the film formation liquid containing a 2nd chemical | medical agent and a 3rd chemical | medical agent. The measurement results with the crystal resonator electrode device 16 in this experiment are shown in FIG. A ferrite film was formed on the surface of the crystal member electrode device 16 in contact with the film forming liquid of the metal member (stainless steel) 18, and the weight of the metal member 18 increased. As shown in FIG. 9, the weight of the metal member 18 increased rapidly in the initial stage and then increased linearly. When 3 hours had elapsed since the crystal resonator electrode device 16 and the stainless steel test piece were simultaneously immersed in the film forming solution, the stainless steel test piece was taken out of the film forming solution, and the weight of the stainless steel test piece was measured. The weight of the measured stainless steel test piece is shown by a black circle in FIG. The measured weight of the stainless steel test piece substantially coincided with the weight of the metal member 18 measured by the crystal resonator electrode device 16 when 3 hours had elapsed after being immersed in the film forming solution. The weights of the two agree with each other within 15%. From the measurement result of the crystal unit electrode device 16, the amount of the ferrite film on the surface in contact with the film forming liquid of the stainless steel member that is a component of the nuclear power plant is measured. I found it possible. By efficiently measuring the amount of the ferrite film formed using the crystal resonator electrode device 16, it is possible to efficiently confirm that a predetermined amount (predetermined thickness) of the ferrite film is formed on the surface of the component of the nuclear power plant. As a result, it is now possible to properly determine the end time of the ferrite film forming operation.

  When the metal member 18 is enlarged to increase the surface area in contact with the film forming liquid, the crystal 17 is vibrated through the metal member 18 by the flow of the film forming liquid. For this reason, the frequency of the crystal 17 increases, and it is measured as if the formation amount of the ferrite film on the surface of the metal member 18 is increased. In order to avoid such an increase in noise, the size of the metal member 18 needs to be set appropriately.

The Raman spectrum of the ferrite film formed on the surface of the metal member 18 was measured. FIG. 10 shows the measurement result of the Raman spectrum. As shown in FIG. 10, the Raman spectrum of the ferrite film formed on the surface of the metal member 18 according to the present invention coincided with the standard spectrum of magnetite (Fe ₃ O ₄ ). From the results described above, it was confirmed that the film formed on the surface of the metal member 18 of the crystal resonator electrode device 16 was a magnetite (Fe ₃ O ₄ ) film.

  In the general theory of film formation in an aqueous solution, the film formation rate on the surface of the constituent member is expressed by equation (1).

V = KN (α) (1)
Here, K represents the impurity coefficient of the aqueous solution, N represents the mass transfer coefficient, and α represents the degree of supersaturation. That is, the thickness of the ferrite film formed on the surface of the constituent member of the nuclear power plant can be estimated by determining the formation rate of the ferrite film based on the measured weight change. The degree of supersaturation α is determined by the amount of drug injected into the film-forming solution when forming the ferrite film. For this reason, when the formation rate of the ferrite film is slow, the formation rate of the ferrite film can be increased by adjusting the amount of the agent injected into the film formation solution so that the degree of supersaturation α increases.

  It is desirable that the crystal resonator electrode device 16 is disposed in a film forming liquid pipe of a film forming apparatus connected to a pipe for forming a ferrite film of a nuclear power plant. When the pipe forming the ferrite film is a recirculation system pipe of a BWR plant, a stainless steel member constituting the recirculation system pipe is used for the metal member 18, and the pipe forming the ferrite film is a reactor coolant for the BWR plant. In the case of the purification system pipe, a carbon steel member constituting the reactor coolant purification system pipe is used for the metal member 18. The crystal resonator electrode device 16 can also be used when a ferrite film is formed on the inner surface of the piping of the PWR plant.

  An example of a method for forming a ferrite film on the surface of a nuclear plant component according to the present invention, which reflects the results of the studies by the inventors described above, will be described below.

  A method of forming a ferrite film on the surface of a nuclear plant component of Example 1 applied to a recirculation system piping of a BWR plant, which is a preferred embodiment of the present invention, is shown in FIGS. Will be described below.

  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. In the water supply system, a condensate pump 5, a condensate purification device 6, a feed water pump 7, a low pressure feed water heater 8, and a high pressure feed water heater 9 are installed in this order on a feed water pipe 10 connecting the condenser 4 and the RPV 12. Yes. 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 boosted by the feed water pump 7 is heated by the low pressure feed water heater 8 and the high pressure feed water heater 9 and guided into the RPV 12. Extracted steam extracted from the main steam pipe 2 and the turbine 3 by the extracted pipe 15 is supplied to the low-pressure feed water heater 8 and the high-pressure feed water heater 9, respectively, and serves as a heating source for the feed water.

  A part of the cooling water flowing in the recirculation system pipe 22 flows into the purification system pipe 20 by driving the purification system pump 24, and after being cooled by the regenerative heat exchanger 25 and the non-regenerative heat exchanger 26, the furnace It is purified by the 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.

  After the operation of the BWR plant is stopped in order to carry out the periodic inspection of the BWR plant, one end of the film forming liquid pipe (circulation pipe) 35 of the film forming apparatus 30 which is a temporary facility is connected to the purification system pipe 20. The other end of the forming liquid pipe 35 is connected to the recirculation system pipe 22. Specifically, the bonnet of the valve 23 of the purification system pipe 20 connected to the recirculation system pipe 22 is opened, and the reactor water purification device 27 side of the bonnet is closed. One end of the film forming liquid pipe 35 is connected to the flange of the valve 23. By such an operation, the film forming liquid pipe 35 is connected to the recirculation system pipe 22 downstream of the recirculation pump 21 through a part of the purification system pipe 20. The other end of the film forming liquid pipe 35 is connected to the drain pipe (or instrumentation pipe) connected to the recirculation system pipe 22 downstream of the recirculation pump 21. The film forming apparatus 30 is connected to a recirculation system pipe 22 which is a pipe for forming a ferrite film on the inner surface. By connecting the film-forming liquid pipe 35 as described above, a film-forming liquid circulation channel connected to the film-forming liquid pipe 35, a part of the purification system pipe 20, the recirculation system pipe 22 and the film-forming liquid pipe 35 is formed. Is done.

  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 film forming liquid pipe 35, chemical liquid tanks 40, 45, 46, a filter 51, a decomposition apparatus 64, and a cation exchange resin tower 60. The on-off valve 47, the circulation pump 48, the valve 49, the heater 53, the valves 55, 56, 57, the surge tank 31, the circulation pump 32, the valve 33, and the on-off valve 34 are provided in the film forming liquid pipe 35 in this order from the upstream. ing. A valve 50 and a filter 51 are installed in a pipe 71 that bypasses the valve 49 and is connected to the film forming liquid pipe 35. A pipe 66 that bypasses the heater 53 and the valve 55 is connected to the film forming liquid 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 film forming liquid 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 apparatus 64 are installed bypasses the valve 57 and is connected to the film forming liquid 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 film forming liquid 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 film forming liquid pipe 35 between the valve 33 and the circulation pump 32, and further connected to the surge tank 31. In order to reduce and dissolve the potassium permanganate (oxidation decontamination agent) used for oxidizing and dissolving the contaminants on the inner surface of the recirculation system pipe 22 forming the ferrite film, and further, the contaminants in the recirculation system pipe 22 A hopper (not shown) for supplying oxalic acid (reductive decontamination agent) to be used into the surge tank 31 is provided in the ejector 37.

  The iron (II) ion implantation apparatus includes a chemical solution tank 45, an injection pump 43, and an injection pipe 72. The chemical liquid tank 45 is connected to the film forming liquid pipe 35 by an injection pipe 72 having an injection pump 43 and a valve 41. The chemical liquid tank 45 is filled with a medicine 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 includes a chemical tank 46, an injection pump 44, and an injection pipe 73. The chemical liquid tank 46 is connected to the film forming liquid 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 oxidant. The pH adjuster injection device includes a chemical tank 40, an injection pump 39, and an injection pipe 74. The chemical liquid tank 40 is connected to the film forming liquid 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 adjusting agent.

  In the present embodiment, the first connection point (connection point between the injection pipe 74 and the film formation liquid pipe 35) 77 to the film formation liquid pipe 35 of the pH adjusting agent injection apparatus, the film formation liquid pipe of the iron (II) ion implantation apparatus. 35 and a third connection point (injection pipe 73 and film-forming liquid pipe 35 to the film-forming liquid pipe 35 of the oxidizer injection device). The first connection point 77 is located on the most upstream side. The second connection point 78 is located downstream from the first connection point 77, and the third connection point 79 is located downstream from the second connection point 78. The third connection point 78 is preferably located as close as possible to the target site for chemical decontamination and ferrite film formation in the film forming liquid piping 35. A pipe 75 provided with a valve 54 communicates the pipe 73 and the pipe 69. The surge tank 31 is filled with water used for processing. In order to remove oxygen contained in the film forming liquid, 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 the counter anion of the iron (II) ion, an organic acid that can be decomposed into water or 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 decomposition device 64 also decomposes an organic acid (for example, oxalic acid) used for reductive decontamination.

  The film thickness measuring device (film forming amount measuring device) includes the above-described crystal resonator electrode device 16 and the film thickness calculating device (film forming amount calculating device) 29. The metal member 18 of the crystal resonator electrode device 16 is made of stainless steel that constitutes a recirculation piping 22 that is a component of the BWR plant. A structure for attaching the crystal resonator electrode device 16 to the film forming liquid pipe 35 will be described in detail with reference to FIG. The valve bonnet 28 from which the valve body has been removed is attached to the film forming liquid pipe 35 downstream of the third connection point 79. Specifically, the flanges 80 </ b> A and 80 </ b> B of the valve bonnet 28 are connected to the film forming liquid pipe 35. The crystal resonator electrode device 16 is disposed in the valve bonnet 28. A long electrode holder 19 of the crystal resonator electrode device 16 is attached to a flange 81 attached to the valve bonnet 28 using a feedthrough 82. Two wires 83 penetrating through the electrode holder 19 are connected to the crystal 17. These wires 83 are connected to the film thickness calculation device 29.

  In the crystal oscillator electrode device 16, a metal member 18 is directly attached to the crystal 17. However, an oxide such as titanium oxide may be attached to the surface of the crystal 17 and the metal member 18 may be installed on the attached oxide by vapor deposition. In the case of a metal member that is difficult to attach to the crystal 17 using an alloy such as stainless steel, gold, platinum, or the like may be attached to the crystal 17 as a substitute.

  The method for forming a ferrite film in this example will be described in detail with reference to FIG. First, the film forming apparatus 30 is connected to the piping system to be coated (Step S1). After the operation of the BWR plant is stopped for the periodic inspection of the BWR plant, the film forming liquid pipe 35 is connected to the recirculation system pipe 22 which is the pipe system to be formed with the film as described above.

  Chemical decontamination is performed on the film formation target portion (step S2). An oxide film containing a radionuclide is formed on the inner surface of the recirculation pipe 22 that contacts the cooling water in the RPV 12. The formation of the ferrite film on the inner surface of the recirculation system pipe 22 is intended to suppress adhesion of radionuclides on the inner surface, but in the formation, chemical decontamination is previously performed on the inner surface of the recirculation system pipe 22. It is preferable to carry out.

  The chemical decontamination applied in step S2 is performed using a known method (see Japanese Patent Laid-Open No. 2000-105295) as described in Japanese Patent Laid-Open No. 2007-182604. With the valves 34, 33, 57, 56, 55, 49, 47 opened and the other valves closed, the circulation pumps 32, 48 are driven. Thereby, the water in the surge tank 31 is circulated in the recirculation system pipe 22. The temperature of the circulating water is raised to about 90 ° C. by the heater 53 and the valve 36 is opened. A required amount of potassium permanganate supplied from a hopper connected to the ejector 37 is introduced into the surge tank 31 through the pipe 70 and is dissolved therein. The oxidative decontamination solution (potassium permanganate aqueous solution) generated in the surge tank 31 is supplied into the recirculation piping 22 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 recirculation pipe 22.

  After the oxidative decontamination is completed, oxalic acid is injected into the surge tank 31 from the hopper. This oxalic acid decomposes potassium permanganate. Thereafter, the reductive decontamination liquid (oxalic acid aqueous solution) generated in the surge tank 31 and adjusted in pH is supplied into the recirculation system pipe 22 by the circulation pump 32. Corrosion products present on the inner surface of the recirculation piping 22 are removed by the reducing decontamination solution. The pH of the reductive decontamination liquid is adjusted by hydrazine supplied from the chemical liquid tank 40 into the film forming liquid pipe 35. A part of the reductive decontamination liquid discharged from the recirculation system pipe 22 is guided to the cation exchange resin tower 60 in order to remove metal cations.

  After the completion of the reductive decontamination, a part of the reductive decontamination liquid flowing in the film forming liquid 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.

  When a ferrite film is formed in piping (such as recirculation piping and water supply piping) of a new plant, for example, a new BWR plant, it is not necessary to perform the chemical decontamination process in step S2.

  After chemical decontamination of the recirculation system pipe 22 is completed, a ferrite film forming process is executed.

  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 film forming liquid 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 water flow through the filter 51 is for removing fine solids remaining in the water. If this solid substance remains, a ferrite film is also formed on the surface of the solid substance when the ferrite film is formed at the film formation target site, and the drug is wasted. By removing the solid matter, the drug contained in the film-forming aqueous solution can be used effectively. 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. Further, by opening the valve 56 and closing the valve 63, the water flow to the mixed bed resin tower 62 used in the purification system operation is stopped.

  The predetermined temperature of the film-forming aqueous solution is preferably about 90 ° C., but is not limited thereto. The point is that the film structure such as crystals of the formed ferrite film can be formed densely enough to suppress the attachment of the radionuclide to the inner surface of the stainless steel recirculation pipe 22 during the operation of the nuclear reactor. is there. Therefore, the temperature of the film-forming aqueous solution is preferably 200 ° C. or lower. The lower limit of the temperature of the film-forming aqueous solution may be 20 ° C., but is preferably 60 ° C. or more, at which the ferrite film formation rate is within the practical range. When the temperature is higher than 100 ° C., the boiling of the aqueous solution for forming a film is suppressed, so that pressure must be applied and the pressure resistance of the temporary equipment is required. Therefore, the temperature of the film-forming aqueous solution in the film-forming treatment is more preferably 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 pH adjuster (third drug) is injected into the film-forming aqueous solution (step S4). By opening the valve 38 and driving the injection pump 39, a pH adjusting agent (for example, hydrazine) is formed into a film at a predetermined temperature (for example, 90 ° C.) flowing from the chemical liquid tank 40 through the film forming liquid pipe 35. Inject into an aqueous solution (water when the pH adjuster is injected for the first time). A pH meter (pH measuring device) 76 is installed in the film forming liquid pipe 35 downstream from the third connection point 79. The pH meter 76 measures the pH of the film forming aqueous solution flowing through the film forming liquid pipe 35. A control device (not shown) adjusts the rotation speed of the infusion pump 39 (or the opening of the valve 38) based on the measured pH value, and adjusts the pH of the film-forming aqueous solution to a range of 6.0 to 9.0. For example, it is adjusted to 7.0.

  A chemical solution (first drug) containing iron (II) ions is injected into the film-forming aqueous solution (step S5). The valve 41 is opened and the infusion pump 43 is driven, and the chemical liquid (first chemical) containing iron (II) ions and formic acid flows from the chemical liquid tank 45 through the film forming liquid pipe 35 and contains hydrazine. Pour into the forming aqueous solution. The first drug injected here contains, for example, iron (II) ions prepared by dissolving iron with formic acid. Part of the implanted iron (II) ions becomes ferrous hydroxide in the film-forming aqueous solution.

  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 hydrogen peroxide as an oxidant flows from the chemical tank 46 through the film forming liquid pipe 35 and contains hydrazine, iron (II) ions and ferrous hydroxide. Pour into the forming aqueous solution. As the oxidizing agent, in addition to hydrogen peroxide, a chemical in which ozone or oxygen is dissolved may be used.

  Since the circulation pumps 32 and 48 are driven by a pH 7.0 film-forming aqueous solution containing hydrazine, iron (II) ions, ferrous hydroxide and hydrogen peroxide, the valve 34 is controlled by the film-forming liquid pipe 35. Through the recirculation system pipe 22. This film-forming aqueous solution flows in the recirculation system pipe 22, is returned to the valve 47 side of the film-forming liquid pipe 35, supplied with a chemical solution containing hydrazine, iron (II) ions and formic acid, and hydrogen peroxide again. It is guided into the recirculation piping 22. When the film-forming aqueous solution (film-forming liquid) comes into contact with the inner surface of the recirculation system pipe 22, iron (II) ions are adsorbed on the inner surface of the recirculation system pipe 22 that is a stainless steel member. The adsorbed iron (II) ions are ferritized by the action of hydrogen peroxide. Ferrous hydroxide in the film-forming aqueous solution reacts with hydrogen peroxide to generate magnetite. This magnetite is adsorbed on the inner surface of the recirculation system pipe 22 through an interfacial reaction. As described above, a ferrite film containing magnetite as a main component (hereinafter referred to as a magnetite film) is formed on the inner surface of the recirculation piping 22 that contacts the film-forming aqueous solution. That is, the inner surface of the recirculation piping 22 that contacts the film-forming aqueous solution is covered with the magnetite film.

  Steps S4, S5 and S6 are preferably carried out continuously. More specifically, when the film-forming aqueous solution into which the pH adjusting agent is injected at the first connection point 77 reaches the second connection point 78, injection of a chemical solution containing iron (II) ions into the film-forming aqueous solution is performed. It is preferable to start. When the film forming aqueous solution containing the pH adjusting agent and iron (II) ions reaches the third connection point 79, it is preferable to immediately inject the oxidizing agent into the film forming aqueous solution.

  When an oxidizing agent is supplied to a film-forming aqueous solution containing iron (II) ions, the oxidation reaction of iron (II) ions starts, so the iron (II) ions and iron (III) ions in the film-forming aqueous solution The abundance ratio is a condition suitable for the formation reaction of the ferrite film. In the film-forming aqueous solution, iron (II) ions and ferrous hydroxide exist in an equilibrium constant state. For this reason, if iron (II) ions in the film-forming aqueous solution decrease, iron (II) ions are supplied from ferrous hydroxide in the film-forming aqueous solution. In order to prevent the formation of a useless magnetite film on the inner surface of the film forming liquid pipe 35, the injection point of the oxidizing agent into the film forming liquid pipe 35 is a position close to the recirculation system pipe 22 that is the film forming position, that is, A position close to the connection point between the valve 34 and the film-forming liquid pipe 35 is preferable.

  The formation amount of the ferrite film formed at the film formation target location is measured (step S7). While the film-forming aqueous solution is supplied to the recirculation system pipe 22 through the film formation liquid pipe 35 and the magnetite film is formed on the inner surface of the recirculation system pipe 22, the crystal resonator electrode device 16 disposed in the valve bonnet 28. The surface of the metal member 18 is also in contact with a film-forming aqueous solution containing iron (II) ions, hydrogen peroxide and hydrazine. For this reason, a magnetite film is also formed on the surface of the metal member 18, which is the same material as the recirculation system pipe 22, similarly to the inner surface of the recirculation system pipe 22. The thickness of the magnetite film formed on the surface of the metal member 18 is substantially the same as the thickness of the magnetite film formed on the inner surface of the recirculation system pipe 22. By measuring the thickness of the magnetite film formed on the surface of the metal member 18, the thickness of the magnetite film formed on the inner surface of the recirculation system pipe 22 can be known.

  The measurement of the thickness of the magnetite film formed on the surface of the metal member 18 of the crystal resonator electrode device 16 will be described in detail. While supplying the film-forming aqueous solution to the recirculation pipe 22, a voltage is applied to the crystal 17 from the film thickness calculation device 29 through one wire 83. By applying this voltage, the crystal 17 is vibrated. The metal member 18 also vibrates together with the crystal 17. The frequencies of the crystal 17 and the metal member 18 are transmitted to the film thickness calculation device 29 through another wiring 83 connected to the crystal 17. Since the metal member 18 becomes heavier as the thickness of the magnetite film formed on the surface of the metal member 18 increases, the frequency of the crystal 17 including the metal member 18 is such that the metal member 18 is not in contact with the film-forming aqueous solution. The frequency of the crystal 17 including the metal member 18, that is, the frequency of the crystal 17 including the metal member 18 when the magnetite film is not formed on the surface of the metal member 18 is decreased. The difference between these frequencies represents the weight of the metal member 18 increased by forming a magnetite film on the surface of the metal member 18. Based on the input frequency, the film thickness calculation device 29 calculates the difference in frequency, that is, the increase in the weight of the metal member 18 due to the formation of the magnetite film. This increase in weight is the weight of the magnetite film formed on the surface of the metal member 18.

  The film thickness calculation device 29 obtains the thickness of the magnetite film on the surface of the metal member 18 based on the calculated weight of the magnetite film. The thickness of the magnetite film is calculated by the film thickness calculation device 29 as follows. The film thickness calculation device 29 calculates the volume of the magnetite film formed on the surface of the metal member 18 by dividing the calculated weight of the magnetite film by the density of the magnetite film. The film thickness calculation device 29 calculates the thickness of the magnetite film formed on the surface of the metal member 18 by dividing the obtained volume of the magnetite film by the area of the metal member 18. As described above, the thickness of the magnetite film formed on the surface of the metal member 18 is continuously measured by the film thickness calculating device 29 while supplying the film forming aqueous solution to the recirculation system pipe 22. .

  It is determined whether the ferrite film formation process is completed (step S8). The control device 84 inputs the thickness of the magnetite film formed on the surface of the metal member 18 obtained by the film thickness calculation device 29 and compares it with the set thickness of the magnetite film. The set thickness of the magnetite film is the thickness of the magnetite film to be formed on the inner surface of the recirculation pipe 22. When the control device 84 determines that the thickness of the calculated magnetite film is thinner than the set thickness of the latter magnetite (the determination result of step S8 is “NO”), the processes of steps S3 to S8 are repeated. . When the calculated thickness of the magnetite film reaches the set thickness of the latter magnetite film, the controller 84 stops the injection pumps 39, 43 and 44. Thereby, supply to the chemical | medical solution containing an iron (II) ion in the film formation liquid piping 35, an oxidizing agent, and a pH adjuster is stopped, and the formation operation of a magnetite film | membrane is complete | finished. Instead of stopping the infusion pumps 39, 43 and 44, the valves 38, 41 and 42 may be closed by the controller 84.

  When the thickness of the magnetite film formed on the surface of the metal member 18 obtained by the film thickness calculation device 29 reaches the set thickness of the magnetite film, the operator stops driving the injection pumps 39, 43 and 44. Also good. In this case, a control device is unnecessary. The thickness of the magnetite film formed on the surface of the metal member 18 obtained by the film thickness calculation device 29 is displayed on the display device, and the operator sees the thickness displayed on the display device, and the infusion pumps 39, 43 and 44 It is determined whether or not the drive can be stopped. When the displayed thickness reaches the set thickness, the worker stops the infusion pumps 39, 43 and 44 as described above.

  In order to stop the formation of the magnetite film on the inner surface of the recirculation system pipe 22, the injection pumps 43 and 44 are stopped to inject the chemical solution containing iron (II) ions and the oxidizing agent into the film forming aqueous solution. Just stop. Instead of stopping the infusion pumps 43 and 44, the valves 41 and 42 may be closed. Stopping the injection pump 39 at the end of the magnetite film forming operation can prevent excess hydrazine from being injected into the film forming aqueous solution, and can shorten the time required for the decomposition of hydrazine in step S9 described later.

  After completion of the magnetite film forming operation, the chemical contained in the film-forming aqueous solution is decomposed (step S9). The film-forming aqueous solution used for forming the magnetite film on the inner surface of the recirculation piping 22 contains hydrazine and formic acid, which is an organic acid, even after the formation of the magnetite 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 film-forming liquid 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. 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, the quartz resonator electrode device 16 is disposed in the film forming liquid pipe 35 and the thickness of the magnetite film formed on the inner surface of the recirculation system pipe 22 which is the film forming target location is detected. The thickness can be measured while supplying the film-forming aqueous solution to the recirculation pipe 22. And the measurement result of the thickness can be obtained continuously during the supply period of the film-forming aqueous solution. For this reason, in this embodiment, when the thickness of the magnetite film measured by the crystal resonator electrode device 16 reaches the set thickness during the period when the film-forming aqueous solution is supplied to the recirculation system pipe 22, at least The supply of the chemical solution containing iron (II) ions and the oxidizing agent into the film forming solution pipe 35 can be stopped. Thereby, the operation of forming the magnetite film on the inner surface of the recirculation pipe 22 is completed. Such a present Example can shorten the time required from the start of the ferrite film formation work to the end of the work. Furthermore, the present Example can confirm that the magnetite film | membrane of predetermined thickness was formed in the inner surface of the recirculation system piping 22 which is a film formation object.

  Since the present embodiment supplies the film-forming aqueous solution containing a chemical solution containing iron (II) ions and an oxidizing agent and having a pH in the range of 6.0 to 9.0 into the recirculation system pipe 22, A dense ferrite film can be formed on the front surface of the inner surface of the recirculation pipe 22 in contact with the film-forming aqueous solution. For this reason, it can suppress that a radionuclide adheres to the inner surface which contacts the cooling water of the recirculation system piping 22. FIG.

  In this embodiment, the crystal resonator electrode device 16 is used for continuous measurement of the ferrite film formation amount. However, instead of the crystal resonator electrode device 16, a measurement method capable of continuously measuring the formed ferrite film amount, for example, AC An electrochemical method such as an impedance method may be used.

  A method for forming a ferrite film on the surface of a nuclear plant constituent member of Example 2 applied to a recirculation system piping of a BWR plant, which is another example of the present invention, will be described below with reference to FIG. Unlike the film forming apparatus 30, the film forming apparatus 30 </ b> A used in the method for forming a ferrite film of the present embodiment has a valve bonnet 28 to which the crystal resonator electrode device 16 is attached connected to the film forming liquid pipe 35 upstream of the on-off valve 47. The configuration is provided. Other configurations of the film forming apparatus 30A are the same as those of the film forming apparatus 30. In the present embodiment, a magnetite film is formed on the inner surface of the recirculation piping 22 using the film forming apparatus 30A as in the first embodiment.

  A magnetite film is formed on the surface of the metal member 18 of the crystal resonator electrode device 16 that comes into contact with the film-forming aqueous solution. The film-forming aqueous solution returned from the recirculation system pipe 22 to the film-forming pipe 35 contains iron (II) ions, hydrogen peroxide, and hydrazine that are lower than the respective concentrations in the film-forming aqueous solution supplied to the recirculation system pipe 22. It is out. Due to the action of these substances, a magnetite film is formed on the surface of the metal member 18.

  In this embodiment, when the thickness of the magnetite film obtained by the film thickness calculation device 29 reaches the set thickness, the control device 84 stops the infusion pumps 39, 43 and 44. When the thickness of the magnetite film obtained by the film thickness calculation device 29 reaches the set thickness, the thickness of the magnetite film formed on the inner surface of the recirculation pipe 22 that is the film formation target is equal to or greater than the set thickness. In this embodiment as well, each effect produced in Embodiment 1 can be obtained.

  In the present embodiment, another valve bonnet 28 to which the crystal resonator electrode device 16 is attached may be further installed in the film forming liquid pipe 35 downstream of the third connection point 79 as in the first embodiment. In this case, the above-described film thickness calculation device 29 inputs the frequency of the crystal 17 or the like of the crystal resonator electrode device 16 provided in another valve bonnet 28 and the metal member of the crystal resonator electrode device 16 The thickness of the magnetite film formed on the surface of 18 is calculated.

  A method for forming a ferrite film on the surface of a nuclear plant component of Example 3 applied to a recirculation system piping of a BWR plant, which is another example of the present invention, will be described below with reference to FIGS. 12 and 13. To do. The film forming apparatus 30B used in the present embodiment has a configuration in which the control device 84 of the film forming apparatus 30 is replaced with a control device 84A (see FIG. 12). Other configurations of the film forming apparatus 30B are the same as those of the film forming apparatus 30. The film forming apparatus 30 </ b> B has a pH controller 85. The pH controller 85 is also provided in the film forming apparatuses 30 and 30A.

  The method for forming a ferrite film on the surface of a nuclear plant component according to the present embodiment performs the operations and processes of steps S1 to S9 performed in the first embodiment. In the present embodiment, the injection amount of the chemical solution is controlled between step S7 and step S8 (step S10). The injection amount of the chemical solution is controlled as follows.

  In step S7, as described above, the amount of ferrite film formed is measured. That is, the film thickness calculation device 29 calculates the thickness of the magnetite film formed on the surface of the metal member 18 in contact with the film-forming aqueous solution based on the frequency of the crystal 17 and the metal member 18 of the crystal resonator electrode device 16. calculate. The calculated magnetite film thickness is input to the control device 84A. The controller 84A calculates the formation rate of the magnetite film based on the thickness of the magnetite film continuously input from the film thickness calculation device 29, and whether or not the obtained film formation rate deviates from the target film formation rate. Determine.

  When the calculated film formation speed deviates from the target film formation speed, the control device 84A controls the rotational speeds of the infusion pumps 43 and 44, and a film formation solution of a drug containing iron (II) ions and hydrogen peroxide. The amount injected into the pipe 35 is adjusted. For example, when the calculated film formation rate is smaller than the target film formation rate, the rotation speeds of the infusion pumps 43 and 44 are increased, and the agent containing iron (II) ions into the film formation liquid pipe 35 and the excess The injection amount of hydrogen oxide is increased. These increases in the injection amount lower the pH of the film-forming aqueous solution flowing in the film-forming liquid pipe 35. When the pH of the film-forming aqueous solution measured by the pH meter 76 decreases from the set pH, the pH controller (another controller) 85 increases the number of injections of hydrazine by increasing the number of revolutions of the injection pump 39, The pH of the film-forming aqueous solution is maintained at a set pH (within a range of 6.0 to 9.0, for example, 7.0). By the control of the injection pumps 43 and 44 described above, the formation speed of the magnetite film formed on the inner surface of the recirculation system pipe 22 is increased, and the target film formation speed is maintained.

  If the calculated film formation rate is higher than the target film formation rate, the rotational speed of the injection pumps 43 and 44 is decreased by the controller 84A, and iron (II) ions into the film formation liquid pipe 35 are reversed. The injection amount of the medicine containing hydrogen and hydrogen peroxide is reduced. Since the pH of the film-forming aqueous solution rises, the pH controller 85 reduces the number of injections of hydrazine by decreasing the rotation speed of the injection pump 39, and maintains the pH of the film-forming aqueous solution at the set pH. By such control of the injection pumps 43 and 44, the formation speed of the magnetite film formed on the inner surface of the recirculation system pipe 22 is reduced, and the target film formation speed is maintained.

  When the control device 84A determines that the thickness of the magnetite coating formed on the surface of the metal member 18 obtained by the coating thickness calculation device 29 has reached the set thickness (step S8), the control device 84A Similarly, the infusion pumps 39, 43 and 44 are stopped.

  Also in the present embodiment, each effect generated in the first embodiment can be obtained.

  Further, in this embodiment, the amount of magnetite film formed can be controlled based on the measured thickness of the magnetite film, so that a magnetite film having a set thickness can be formed in a shorter time. When the calculated film formation rate is smaller than the target film formation rate, the injection amount of a chemical containing iron (II) ions and an oxidizing agent, for example, hydrogen peroxide into the film formation liquid pipe 35 is increased. As a result, the film formation rate is increased to the target film formation rate, and the magnetite film having the set thickness can be formed in a shorter time. Further, when the calculated film formation rate is higher than the target film formation rate, the film formation rate is decreased so as to become the target film formation rate, and the magnetite film having the set thickness can be formed in a shorter time.

  If the amount of the agent containing iron (II) ions and the oxidizing agent injected into the film forming liquid pipe 35 becomes too large, a magnetite film is formed on the inner surface of the recirculation system pipe 22, and in the film forming aqueous solution. Nuclei that grow into magnetite are generated, and magnetite particles that become dust are formed in the film-forming aqueous solution around the nucleus. For this reason, the formation speed of the magnetite film on the inner surface of the recirculation system pipe 22 is suppressed, and it takes time to form the magnetite film on the inner surface. The target film formation rate is set so as to avoid that the amount of the drug containing iron (II) ions and the oxidizing agent injected into the film formation liquid pipe 35 becomes too large and the film formation rate is suppressed. Therefore, when the calculated film formation rate is greater than the target film formation rate, the magnetite film with the set thickness can be formed in a shorter time by reducing the film formation rate to the target film formation rate. Can do.

  In this embodiment, since the crystal resonator electrode device 16 is disposed on the supply side of the film forming aqueous solution to the recirculation system pipe 22 of the film forming liquid pipe 35, the film on the inner surface of the recirculation system pipe 22. The film formation rate can be determined earlier at a stage earlier than the formation. For this reason, the injection amount of the chemical | medical agent containing iron (II) ion and an oxidizing agent can be controlled early, and the film formation speed | rate on the inner surface of the recirculation system piping 22 can be adjusted earlier.

  In the present embodiment, the valve bonnet 28 to which the crystal resonator electrode device 16 is attached may be provided not in the downstream of the on-off valve 41 but in the film forming liquid pipe 35 upstream of the on-off valve 47 as in the second embodiment. . Further, the valve bonnet 28 to which the crystal resonator electrode device 16 is attached may be installed at two locations upstream of the on-off valve 47 and downstream of the on-off valve 41.

  A method for forming a ferrite film on the surface of a nuclear plant component 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 coolant purification system in the regenerative heat exchanger 25 into which high-temperature cooling water from the RPV 12 flows and the purification system piping 20 in the vicinity thereof. The purification system pipe 20 is made of carbon steel. Valves 86 and 87 are provided in the purification system pipe 20 upstream and downstream of the regenerative heat exchanger 25.

  The bonnet of the valve 86 is opened, and one end of the film forming liquid pipe 35 of the film forming apparatus 30 is connected to the bonnet flange of the valve 86 opened. The valve 23 is closed. The bonnet of the valve 87 is opened to seal the flange on the non-regenerative heat exchanger 26 side. The other end of the film forming liquid pipe 35 of the film forming apparatus 30 is connected to the hood flange of the valve 87 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 film forming liquid pipe 35.

  Also in the present embodiment, the operations and processes of steps S1 to S9 in the first embodiment are executed. In the present embodiment, the metal member 18 of the crystal resonator electrode device 16 is the same carbon steel member as the purification system pipe 20. Also in the present embodiment, a magnetite film is formed on the inner surface of the purification system pipe 20 and the inner surface of the non-regenerative heat exchanger 26 that are in contact with the film-forming aqueous solution. The surface of the structural member in contact with the film-forming aqueous solution among the constituent members of the reactor purification system is covered with the magnetite film.

  Also in this embodiment, each effect produced in the first embodiment can be obtained. In this embodiment, the surface of the carbon steel member that contacts the cooling water can be covered with a dense magnetite film, so that the corrosion of the carbon steel member of the nuclear power plant can be suppressed.

  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. What is necessary is just to connect the other end of the film formation liquid piping 35 of the film formation apparatus 30. FIG.

  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, the operations and processes in steps S1 to S10 illustrated in FIG. 13 are performed.

  The formation method of the ferrite film on the surface of each plant constituent member of Examples 1, 2 and 3 is made of carbon steel water supply piping of BWR plant, carbon steel water supply piping of PWR plant, carbon steel of thermal power plant. It can be applied to water supply piping and primary coolant piping made of stainless steel for PWR plants. The primary coolant piping of the PWR plant supplies the high-temperature cooling water generated in the reactor pressure vessel to the steam generator, and returns the cooling water discharged from the steam generator to the reactor pressure vessel when the temperature drops. It has a function.

  In the case of forming a ferrite film on the inner surface of the BWR plant that is in contact with the water supply of the carbon steel water supply pipe 10, as shown in FIG. 4 of Japanese Patent Application Laid-Open No. 2007-182604, the film forming apparatuses 30, 30A, and 30B What is necessary is just to connect the both ends of any film formation liquid piping 35 to the water supply piping 10, respectively. Further, when a ferrite film is formed on the inner surface of the water supply pipe of the PWR plant that is in contact with the water supply, as shown in FIG. 8 of Japanese Patent Application Laid-Open No. 2007-182604, one of the film forming apparatuses 30, 30A, and 30B. What is necessary is just to connect the both ends of the film formation liquid piping 35 to the water supply piping, respectively. In the case of forming a ferrite film on the inner surface of the water supply pipe of the thermal power plant that contacts the water supply, as shown in FIG. 9 of Japanese Patent Application Laid-Open No. 2007-182604, the film formation of any one of the film forming apparatuses 30, 30A, and 30B What is necessary is just to connect the both ends of the liquid piping 35 to the water supply piping, respectively. When forming a ferrite film on the inner surface of the PWR plant that contacts the cooling water of the primary coolant pipe, the isolation valve provided in the vicinity of the reactor pressure vessel of the primary coolant pipe is closed and the film-forming aqueous solution becomes the reactor pressure. What is necessary is just to supply film formation aqueous solution in the primary coolant piping using either of the film formation apparatuses 30, 30A, and 30B so that it may not flow into the container.

  DESCRIPTION OF SYMBOLS 1 ... Reactor, 3 ... Turbine, 10 ... Feed water piping, 12 ... Reactor pressure vessel, 13 ... Reactor core, 16 ... Crystal oscillator electrode apparatus, 17 ... Crystal, 18 ... Metal member, 19 ... Electrode holder, 20 ... Purification System piping, 22 ... Recirculation system piping, 29 ... Film thickness calculation device, 30, 30A, 30B ... Film formation device, 35 ... Film formation liquid piping, 39, 43, 44 ... Injection pump, 40, 45, 46 ... Chemical solution Tank, 72, 73, 74 ... injection piping, 64 ... decomposition device, 84,84A ... control device.

Claims (15)

A film forming solution containing iron (II) ions, an oxidizing agent that oxidizes the iron (II) ions, and a pH adjuster is brought into contact with the surface of the plant component that is in contact with water to form a ferrite film on the surface,
Measure the amount of ferrite film formed,
The amount of the chemical solution containing iron (II) ions and the amount of the oxidant injected into the film formation solution is set so that the film formation rate obtained based on the measured formation amount of the ferrite film becomes the set formation rate. Control
Ferrite coating on the surface of a plant component, wherein injection of the chemical liquid containing iron (II) ions and the oxidizing agent into the film forming liquid is stopped based on the measured formation amount of the ferrite film Forming method.   The method for forming a ferrite film on the surface of a plant component according to claim 1, wherein injection of the pH adjusting agent into the film forming liquid is stopped based on the measured formation amount of the ferrite film.   The injection stop of the chemical solution containing iron (II) ions and the oxidizing agent is performed when the thickness of the ferrite film obtained based on the measured formation amount of the ferrite film reaches a set thickness. 2. A method for forming a ferrite film on the surface of a plant constituent member according to 1.   2. The measured formation amount of a ferrite film is the formation amount of a ferrite film formed on the surface of a metal member in contact with the film formation liquid of a crystal resonator electrode device immersed in the film formation liquid. 4. A method for forming a ferrite film on the surface of a plant component according to any one of items 3 to 3.   The method for forming a ferrite film on the surface of the plant constituent member according to claim 4, wherein the metal member is made of the same material as the plant constituent member. A film-forming liquid pipe that supplies a film-forming liquid containing iron (II) ions, an oxidizing agent that oxidizes the iron (II) ions, and a pH adjuster is connected to a target pipe of the plant that is the plant component of the film formation target. connection,
Formation of the ferrite film is performed on the inner surface of the target pipe in contact with the film forming liquid by supplying the film forming liquid to the target pipe through the film forming liquid pipe,
The amount of ferrite film formed is measured, and the amount of ferrite film formed on the metal member in contact with the film forming liquid provided in the film forming amount measuring device attached to the film forming liquid pipe is measured as the film forming amount. Is to measure with a quantity measuring device,
Stopping the injection of the chemical solution containing iron (II) ions and the oxidant into the film forming solution is based on the formation amount of the ferrite film measured by the film formation amount measuring device. The method for forming a ferrite film on the surface of a plant constituent member according to claim 1, wherein injection of the chemical solution containing ions and the oxidizing agent into the film forming solution in the film forming solution pipe is stopped. Connecting both ends of the film forming liquid pipe to the target pipe to form a closed loop including the film forming liquid pipe and the target pipe,
In the measurement of the formation amount of the ferrite film by the film formation amount measuring device, at least one of the film formation liquid supplied to the target pipe and the film formation liquid returned from the target pipe is brought into contact with the metal member. The method for forming a ferrite film on the surface of the plant constituent member according to claim 6, which is performed by:   The method for forming a ferrite film on the surface of a plant constituent member according to claim 6 or 7, wherein a metal member provided in a crystal resonator electrode device is used as the metal member of the film formation amount measuring apparatus.   The method for forming a ferrite film on the surface of a plant constituent member according to any one of claims 6 to 8, wherein the target pipe is a water supply pipe of the plant.   The method for forming a ferrite film on the surface of a plant constituent member according to any one of claims 6 to 8, wherein the target pipe is a pipe that is connected to a nuclear power plant nuclear reactor and through which a coolant in the nuclear reactor flows. .   The formation of a ferrite film on the surface of the plant component according to claim 1, wherein the pH of the film forming liquid is measured, and the injection amount of the pH adjuster into the film forming liquid is controlled based on the measured pH. Method.   The method for forming a ferrite film on a surface of a plant constituent member according to claim 6 or 8, wherein the metal member is made of the same material as the plant constituent member.   A film forming liquid pipe connected to a pipe which is a film forming target of the plant, a first chemical tank for storing a chemical liquid containing iron (II) ions supplied to the film forming liquid pipe, and the film forming liquid pipe A second chemical liquid tank for storing an oxidant supplied to the film, a third chemical liquid tank for storing a pH adjuster supplied to the film forming liquid pipe, and a heating device installed in the film forming liquid pipe A ferrite film formed on the surface of the metal member, having a metal member in contact with the film-forming liquid containing the iron (II) ions, the oxidizing agent, and the pH adjuster flowing in the film-forming liquid pipe Film forming amount measuring device for measuring the amount of formation of iron, and the ferrite that is measured by the film forming amount measuring device for the injection amount of the chemical solution containing iron (II) ions and the oxidizing agent into the film forming solution pipe Film formation The film formation rate obtained based on the control is controlled to be a set formation rate, and the chemical solution containing the iron (II) ions and the film formation solution of the oxidizing agent based on the measured formation amount of the ferrite film A film forming apparatus comprising: a control device for stopping supply into the pipe.   The film forming apparatus includes: a crystal resonator electrode device having a crystal provided with the metal member; and a film formation amount calculating device for calculating a formation amount of a ferrite film based on a frequency of the crystal. The film forming apparatus as described. The crystal oscillator electrode device has the metal member, the crystal, a holding member for holding the crystal, and the seal member,
The film forming apparatus according to claim 14, wherein the sealing member covers the entire surface of the crystal other than the surface in contact with the metal member and the holding member.

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