JP2001305271A - Repair method for in-furnace equipment for nuclear power plants - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the term of work by repairing a part in the atmosphere on the site without bringing the item to be repaired from the site into factory. SOLUTION: When a part to be repaired such as cracks, defect or the like is detected in an item to be repaired, the inner part of the crack or defect is filled with a brazing filler metal and heated to braze it, and the brazed part is covered with, for example, stainless steel by flame spraying or low heat input welding. This repairing method comprises the following processes: the process (a) of removing the surface deteriorated layer of the part to be repaired, the process b of placing a mixture of an alloy powder and an antioxidant (flux) on the repairing part, the process (c) of melting the alloy powder by heating, the process (d) of filling the molten alloy to the defect part, the process (e) of coagulating the alloy in the defect part, and the process (f) of removing the residue.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing in-core equipment for a nuclear power plant, which can partially repair highly corrosion-resistant members such as in-reactor equipment by a simple method.

[0002]

2. Description of the Related Art As equipment in a nuclear power plant, as shown in FIG. 4, a shroud 2 installed in a reactor pressure vessel 1, a jet pump 3, a control rod guide tube 4,
Core spray 5 and the like. The control rod guide tube 4 constitutes a part of the control rod drive mechanism 6. Since these devices are important devices used in a high-temperature, high-pressure water environment, extremely high quality is required, and austenitic stainless steel having high corrosion resistance is used.

In recent years, aging of the plant has been called for, and it is necessary to establish in advance a low-cost and simple repair technique especially when an incompatibility due to stress corrosion cracking (SCC) or the like occurs. The conventional repair method mainly responds by completely removing the defective portion and performing re-welding or by completely replacing the defective device or part.

[0004]

In the conventional repair method described above, since the equipment in the reactor is installed in the reactor pressure vessel 1, the working environment is extremely poor in a limited working space. Moreover, there is a problem that the workability must be improved, such as requiring a great deal of labor.

In addition, when a brazing repair method, which is a method that hardly melts a base material, which is conventionally performed on high-temperature components of a gas turbine, is applied, heat treatment in a vacuum or an inert gas is required. In addition, there is a problem that it is difficult to locally repair large components that are difficult to remove and devices and components that are restricted from being carried out.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an in-core equipment for a nuclear power plant which can efficiently and easily repair a defect locally without bringing parts into a factory. The purpose is to provide a repair method.

[0007]

According to the present invention, there is provided a method for repairing an in-core device for a nuclear power plant, comprising the steps of: removing a surface layer of a repair portion; A mixture adhesion step of closely adhering a repair material comprising a composite of a brazing alloy powder having a lower melting point than a structural member and a flux as an antioxidant, and a synthetic liquid for heating and melting the brazing alloy and filling the repair portion. It is characterized by having a filling step and a residue removing step of removing a residue after filling the combined liquid.

The method of the present invention may include a step of applying only flux to the repair surface before the repair material adheres, or a step of mechanically smoothing the repair surface after the repair, or It is also possible to add a step of coating a slightly thick highly corrosion-resistant layer on the surface by thermal spraying, laser welding, low heat input TIG welding, or low heat input PTA. In the case of thermal spraying,
After the thermal spraying, a step of heating the thermal spraying frame or the like to densify the thermal sprayed layer may be added.

The repair material may be a paste in which alloy powder, flux, and an organic binder are kneaded with a solvent. The alloy powder is composed of Au, Pt, Pd, Ag, Ni, Cu, C
It is composed of an alloy of components selected from o, Fe, Cr, P, Si, B, and Mn, or a mixed powder thereof. The flux comprises one selected from boric acid, borate and fluoride.

As the heating step, local heating such as high-frequency heating, infrared ray condensing heating, laser heating or the like is suitable.
The heating atmosphere is not particularly limited, but may be air or an inert gas blowing atmosphere.

In the repair method of the present invention, an alloy powder of the repair material is melted by heating, and the melt flows into a defective portion of the repair portion of the structural material to be filled. In other words, by previously removing the deteriorated layer such as the oxide layer of the repaired portion generated during use, it is possible to suppress the inhibition of the spread of the synthetic liquid on the repaired surface.

By the action of the flux, the formation of a new oxide layer which hinders the wettability of the composite liquid during the heating and melting of the alloy is prevented, and therefore the defective liquid flows and fills the defective portion satisfactorily. The wettability, for example, the contact angle between the alloy droplet and the substrate, by selecting those that show an acute angle,
The melt wets the defect well and naturally penetrates or flows and fills.

[0013] Since it is necessary to bond well with the wear-resistant member after solidification, the alloy must be selected from alloys composed of components having good adhesion to the wear-resistant member. Such components include, for example, Au, Pt, Pd, Ag, Ni, Cu, Co, Fe, Cr, P,
An alloy whose main component is selected from Si, B, Mn, and the like can be given.

Specifically, for example, Pt, Au-Cu, Au-Ni,
Au-Ni-Cr, Au-Pd-Cu, Au-Pd-Ni, Au-Pd-Mn, Pd
-Ni-Mn, Pd-Ag-Cu, Ag-Pd-In, Ag-Al. Pd-Ni,
M-Cr-Si-B, M-Cr-Si, M-Si, M-Si-B, M
An alloy mainly containing -P, M-Si-B (M: a component selected from Ni, Co, and Fe) and the like can be given.

[0015] When the alloy is in powder form, it is easy for heat to enter,
Therefore, it is easily melted and easily mixed with a flux described later. Although the particle size of the powder is not particularly limited, very fine particles have a large surface area and are easily oxidized.
A diameter of several tens μm to 100 μm is suitable.

When the repair material is in close contact with the repaired portion, the repair material is temporarily fixed until heating, thereby preventing the dispersion of the repair material and improving the workability. Therefore, the repair material can be satisfactorily fixed to the repair portion by kneading the alloy powder, the flux, and the organic binder with a solvent to form a paste. In order to further suppress oxidation, the method may include a step of applying the flux as it is, or a binder, a solvent, or a mixture of a solvent and a binder and applying the flux to the repair surface before the repair material adheres.

The flux is effective as an antioxidant near the melting point of each of the above-mentioned alloys.
Those containing fluoride are exemplified. The mixing ratio between the alloy powder and the antioxidant is determined as appropriate, but as a guide, it is preferable that the volume is about several percent to 100% of the alloy powder. If the amount is too small, the antioxidant effect is small, and if the amount is too large, the ratio of the alloy powder is reduced, and the repair ability is reduced.

The mixing ratio with the organic binder is determined in relation to the viscosity of the organic binder to be used. However, when the adhesive is used as a repair material, it is determined that a state in which it does not flow too much and is not too hard is obtained. Will be better.

The method of removing the surface layer is not particularly limited, and a chemical having a deoxidizing function may be used. However, in an environment where it is difficult to remove such a chemical, a mechanical method such as polishing or blasting may be used. Is advantageous because there is no chemical residue.

Although there is no particular limitation on the heating process, considering the on-site work on members that require a great deal of labor to remove the wear-resistant members, high-frequency heating, which can be heated by a small and simple device, Local heating by infrared condensing heating and laser heating (especially a simple one such as a semiconductor laser) is advantageous.

In addition, these devices do not have a thermal effect on the base material, and mainly heat the repair material and the vicinity of the repair portion.
It is also advantageous from the viewpoint that a heating source with high energy density capable of local heating and good temperature controllability is desirable.

The heating temperature is equal to or higher than the temperature at which the repair material alloy melts, and is usually preferably from 50 ° C. to 100 ° C., which is the melting point of the alloy. If the temperature is too low, it is difficult to sufficiently fill the defective portion, and if the temperature is too high, the thermal influence on the base material on which the member is formed increases. The heating time is not particularly limited, but basically, it is sufficient that the alloy of the repair material is melted, the repair surface is also heated, and a period in which the synthesizing liquid sufficiently flows through the repair surface is maintained.

Specifically, several minutes to at most several tens of minutes is sufficient. During that time, it is necessary to keep the temperature of the repaired part constant so that it does not extremely rise and fall. For this purpose, it is desirable to use a heating device including a device having a temperature control mechanism, that is, a device including a temperature detection device and a temperature holding device.

It is preferable that the repair atmosphere is clean, but in an environment where it is difficult to achieve a perfect atmosphere, even in the air or in a blown atmosphere of an inert gas, a sufficient effect can be obtained by the action of the antioxidant. .

In addition, the repaired portion needs to be properly joined to the member after solidification in order to withstand subsequent use. Therefore, as an alloy having good wettability and excellent bondability with generally widely used austenitic stainless steels, for example, Au, Pt, Pd, Ag, Ni, Cu, Co, Fe, Cr, P, Si, B,
Alloys and alloy powders selected from Mn and the like are listed.

In particular, for nuclear applications, Au, Pt, P
An alloy or an alloy powder whose main component is selected from d, Ni, Co, Cr, P and Si is desirable. For example, Au-Ni, Au-Ni-
Cr, Au-Pd-Cu, Au-Pd-Ni, Au-Pd-Mn, Pd-Ni, Pd
-Ni-Mn, Pd-Ag-Cu, Ag-Pd-In, Ag-Al, M-Cr-
Alloys containing Si, M-Si, MP, (M: a component selected from Ni, Co and Fe) as a main component are exemplified.

After the repair, the defect is firmly filled with the repair material, and there is no leakage of fluid from a defect such as a crack or a thinned portion, so that the defect can be further used. Further, since the base material is hardly melted, residual stress is hardly left locally. Further, since it is not necessary to completely remove devices and components, labor can be greatly reduced.

The repair part may be used in the repair state. However, in order to further secure high corrosion resistance, a high corrosion resistant member may be further formed on the repaired surface by thermal spraying. When a thermal spraying method is used, a high corrosion resistant layer can be formed without melting the base material, and the influence on the base material is small.

The thermal spraying method is not particularly limited as long as it does not require an atmosphere container. A high-speed gas flame thermal spraying (HVOF) method is suitable because the decomposition of the compound is small, but a thermal spray gun is used. Plasma spray (APS = Atmosphere Plasma S)
The pray) method is also simple and convenient. Since the adhesion of the thermal sprayed coating is not large, it is desirable to improve the adhesion by spraying and heating a gas flame or a plasma arc after the thermal spraying to densify the coating.

As the type of the high corrosion resistant material to be sprayed, the repaired member may be coated with a common material (austenitic stainless steel) or an equivalent material. Furthermore, in order to deal with the possibility of component segregation of stainless steel after repair, appropriate heating is applied, components are homogenized, and local component segregation is dispersed to reduce the occurrence of defects during use. Can be.

Other than the thermal spraying method, it is also possible to coat a highly corrosion-resistant member such as austenitic stainless steel by a welding method capable of suppressing heat input as much as possible. Laser welding, PTA welding, TIG
Welding and the like. Further, since the member is an in-furnace device for a nuclear power plant, repair for removal is very difficult, and the repair method according to the present invention is particularly effective.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a method for repairing in-core equipment for a nuclear power plant according to the present invention will be described with reference to FIGS. FIG. 1 is a process diagram of a method according to the present embodiment, and FIG. 2 is a cross-sectional photograph showing two examples after repair according to the present embodiment. In this embodiment, as shown in FIG. 1, the repaired portion has a surface-altered layer process a, the repaired portion has a process of adhering a mixture of an alloy powder and an antioxidant (flux), the heating process has an alloy melting process c, and the repaired portion has a defective portion. It comprises a finance liquid filling step d, a step e for solidifying the alloy in the defective part, and a residue removal step f.

That is, in the step (a), first, the surface of the repaired part requiring repair is degreased and washed using an organic solvent such as ethanol, and then the altered layer on the surface is removed. If the altered layer such as an oxide layer on the surface is thick, it is polished and removed using a grinder or the like to reveal a metal surface. In particular,
For cracks, defects, and the like, repair can be easily performed by removing the defective portion in an inverted triangular shape in the depth direction. Next, the process proceeds to step b, and the repair material is closely attached to the surface of the repair portion by, for example, placing or attaching the repair material. The repair material used is a composite of a material and a flux selected from brazing alloys and the like shown in Table 1. They are laminates, powder mixtures, and the like.
Since the mixture of powders is easily dispersed, if the mixture is kneaded with an organic binder and a solvent (organic or aqueous) and used as a paste, the repair material is less likely to be scattered and is easy to construct.

Next, the process proceeds to step c, and the repair material for the repair surface is repaired in the atmosphere using a heater capable of heating to a temperature equal to or higher than the melting point of the brazing filler metal alloy as the repair material, for example, an infrared ray condensing heater, a high-frequency heater, or a laser. Is heated and melted, and then the process proceeds to step d, in which the defective portion of the repaired portion is filled with the brazing filler metal melt. Next, the process proceeds to step e, where the alloy is solidified at the defective portion, and after cooling, f
Then, the residue such as the residue of the flux is removed with a solvent such as water or ethanol. Thus, the repair of the defective portion of the repair section is completed.

[0035]

[Table 1]

Next, a specific example of the first embodiment will be described. (Example 1) A width of 0.15 mm and a depth of 0.15 mm were artificially provided as defects on an austenitic stainless steel base material to be repaired.
The effectiveness of the repair method was confirmed using two types of groove-like defects having a width of 5 mm (described as Example 1), a width of 0.02 mm, and a depth of 0.3 mm (described as Example 2). As a repair material, a brazing filler metal powder composed of 15 wt% Cr-11P and the balance of Ni, a powder having a particle size of about 10 μm to 44 μm, and a volume ratio of 3: 1 with a flux containing boric acid as a main component.
Was mixed.

Thereafter, an appropriate amount of an aqueous solvent and a binder were mixed and kneaded to an earlobe-like hardness to obtain a repair material. The repair material was placed on a repair surface with a thickness of about 1 mm using a pallet and was brought into close contact with the repair surface. Next, the solvent was evaporated by a dryer and solidified. After that, the melting point of the brazing material is about 100
The surface of the repaired part was heated up to 980 ° C, which is higher by ℃, using an infrared focusing heater. The brazing material melted without being oxidized and spread over the repaired part.

After the repair, the cross sections of these simulated defects were cut and polished and observed with an optical microscope. As a result, all of the artificial defects were completely filled with the brazing material, and no defects such as voids remained. It was found that repairs had been made. FIG. 2 is a cross-sectional view showing a photograph of a cross section of the repaired portion.
(A) shows the state after repair of Example 1 and (b) shows the state after repair in Example 2. In FIG. 2, reference numeral 7 is a stainless steel base material, 8 is a filling repair part for artificial defects of Example 1, and 9 is an example. 2 is a filling and repairing section for an artificial defect.

In the same manner, using the brazing material selected from Table 1 at a temperature about 50 ° C. to 100 ° C. higher than the melting point of each brazing material, using an infrared focusing heater and a high-frequency heating heater, In each case, it was confirmed that the simulated defect was satisfactorily repaired without oxidation.

(Example 2) As in Example 1, an austenitic stainless steel base material having a width of 0.15 mm,
The effectiveness of this repair method was confirmed using two types of groove-like defects with a depth of 0.5 mm, a width of 0.02 mm, and a depth of 0.3 mm. As a repair material
Particle size of brazing filler metal consisting of 15wt% Cr-11P-balance Ni
Was mixed with a flux containing boric acid as a main component at a volume ratio of 3: 1.

Thereafter, an appropriate amount of an aqueous solvent and a binder were mixed and kneaded to an earlobe-like hardness. The repair material was placed on the repair surface to a thickness of about 1 mm using a pallet. Next, the solvent was evaporated by a dryer and solidified. Thereafter, the surface of the repaired part was heated to 980 ° C, which is 100 ° C higher than the melting point of about 880 ° C of the brazing material, using an infrared focusing heater. The brazing material melted without being oxidized and spread over the repaired portion.

Thereafter, the surface of the repaired part was treated with a brass using alumina powder having a particle size of 50 mesh or more to make the surface R-shaped.
a: 2 to 30 μm, Rmax: 10 to 200 μm, and then the above-mentioned stainless steel common material (main component: 18 to 200 Cr-8 to 10 Ni-remaining Fe) was applied to a thickness of about 0.2 by plasma spraying in air. mm
Formed. Thermal spraying conditions were as follows: voltage: 65 V, current: 550 A, argon-hydrogen gas flow rate: 90 liter / min.

After the repair, the cross section of the simulated defect was cut and polished and observed with an optical microscope. As a result, the two types of simulated defects were completely filled with the brazing material, and defects such as voids remained. It was found that the repair was done well. Further, it was found that the thermal sprayed layer was formed well on the surface of the repaired portion, and the repair was well performed.

Next, a second embodiment according to the present invention will be described with reference to FIG. This embodiment is obtained by adding the following steps to the first embodiment shown in FIG. Before the adhesion step b of the mixture of the repair material which is a composite of the brazing alloy and the flux, a flux is applied to the repair surface in advance as an antioxidant application step g by applying a paste with a solvent such as water or an organic solvent. K) using kneading. Thereafter, the repair material is adhered thereon.

After the step of heating and melting the repaired material on the repaired surface, filling the defective portion of the repaired portion with the brazing filler metal melt, and further removing the residue, the highly corrosion-resistant member is sprayed or welded. This is a step i of forming a corrosion-resistant layer by thermal spraying for forming a coating layer. As the thermal spraying method, atmospheric thermal spraying, high-speed gas flame thermal spraying, and the like are suitable.

After the formation of the thermal spray layer, the thermal spray layer is heated using a thermal spray frame (plasma arc or high-temperature gas) (step i), and the thermal spray layer is heated by the thermal spray frame for densification of the thermal spray layer. . In addition, as a welding method, a process k for forming a corrosion-resistant coating layer by low heat input welding such as TIG welding, laser welding, or PTA welding, which can reduce welding heat input to 5 kJ / cm or less, is appropriately provided. In this case, it can be used as welded.

(Example 3) A width of 0.15 mm to 0.3 mm and a depth of 0.3 to 1 artificially provided on an austenitic stainless steel base material.
The effectiveness of this repair method was confirmed using various groove-shaped simulated defects.

15% by weight Cr-30Co-11P as a repair material-balance
Ni, 15wt% Cr-20Ni-3Si-balance Co, 80wt% Au-balance N
i, 34 wt% Pd-30Au-balance Ni, using powders of about 1 μm to 100 μm in particle diameter of about 1 μm to 100 μm, and a volume ratio of boric acid and borosilicate to flux of 1 to 5: 1. Was mixed.

Thereafter, a repair material mixed with an appropriate amount of an aqueous solvent and a binder and kneaded to an earlobe-like hardness was adhered to the repair surface to a thickness of about 1 mm using a pallet. Next, the solvent was evaporated by a dryer and solidified. After that, the melting point of the brazing material was about 880 ° C, 980 ° C, 955 ° C, 1150 ° C, respectively.
The surface of the repaired part was heated to 980 ° C, 1080 ° C, 1055 ° C, and 1250 ° C, which is 100 ° C higher than 100 ° C, using a high-frequency heater or laser light. The brazing material melted without being oxidized and spread over the repaired portion.

Thereafter, the surface of the repaired portion was blasted using alumina powder having a particle size of 50 mesh or less to make the surface Ra: 5.
-20μm, Rmax: After roughening to 30-150μm, the particle size of SUS304 with low carbon content by high-speed gas flame spraying (HVOF) method
It was formed to a thickness of about 0.3 mm using a powder of 10 to 50 μm.
Thermal spraying conditions: flow rate 850m / sec, repair surface temperature about 150-200 ℃
It is.

After the thermal spraying, a gas flame was applied to the repaired surface for 1 to 10 minutes to further heat it. Thereafter, the heat input is reduced and heating is performed for a short time to disperse the component elements of the repaired part. The outermost surface may be slightly melted.

After completion of the repair, the cross section of the simulated defect was cut and polished and observed with an optical microscope. As a result, the two types of simulated defects were completely filled with the brazing material, and defects such as voids remained. It was found that the repair was well done. Further, it was found that the thermal sprayed layer was formed well on the surface of the repaired portion, and the repair was well performed.

Further, the sprayed layer was dense and had good adhesion to the repaired surface. As a material used for thermal spraying,
SUS316 with low carbon content or Ni equivalent to INCONEL182 / 82
When the base alloy was coated, it was confirmed that the repair was similarly well performed.

According to the present embodiment, using the repair material,
Defects can be satisfactorily filled and repaired by heating in the atmosphere. In addition, a common material is formed on the repaired surface, and the surface layer of the repaired portion shows the same characteristics as the initial state. In the present embodiment, a repair material whose main component is Co or Ni was used.However, when the main component of the repair target portion is Fe, the repair material is also closer to the base material when the repair material also uses an Fe-based material. It goes without saying that a repaired part of the characteristics is obtained and effective.

[0055]

According to the present invention, the repair material previously applied to the defective portion is melted by heating, the melt flows into the defective portion to be filled, and thus the repair is firmly performed. Due to the effect of the flux, the formation of oxides is suppressed even by heating in the air,
The combined liquid flows well to the defect in the repair department.

In the present invention, a repair material whose main component is Co or Ni is used. However, when the main component of the repaired portion is Fe, it is more preferable to use an Fe-based material for the repair material. It is effective to obtain a repaired part with characteristics close to.

Further, since it is possible to perform the work in the atmosphere, the object to be repaired is not removed and brought to the factory from the site.
The construction can be done directly on site, and it can contribute to shortening the construction period, and it is also effective for cost reduction.

[Brief description of the drawings]

FIG. 1 is a process chart showing a first embodiment of a method for repairing in-furnace equipment for a nuclear power plant according to the present invention.

FIG. 2A is a cross-sectional view of a repaired part of Example 1 in the first embodiment photographed, and FIG. 2B is a cross-sectional view of a repaired part of Example 1 in the first embodiment.

FIG. 3 is a process diagram showing a second embodiment of the method for repairing in-core equipment for a nuclear power plant according to the present invention.

FIG. 4 is a longitudinal sectional view for explaining the in-furnace equipment for a nuclear power plant.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Shroud, 3 ... Jet pump, 4 ... Control rod guide tube, 5 ... Core spray, 6 ... Control rod drive mechanism, 7 ... Stainless steel base material, 8 ... Filling repair part, 9 ... Filling repair part of the artificial defect of Example 2, a
... removal step of the surface deteriorated layer of the repaired part, b ... adhesion step of the mixture of alloy powder and antioxidant on the repaired part, c ... melting of the alloy powder by heating, d ... filling step of the synthetic liquid with the defective part, e ... defect part Alloy solidification step, f: residue removal step, g: antioxidant application step, h: kneading step using a binder, i: corrosion resistant layer forming step by thermal spraying, j: heating step of thermal sprayed layer by thermal spraying frame, k ... Corrosion resistant layer forming process by low heat input welding.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuo Morishima 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in Toshiba Yokohama Office 4K031 AA04 AA08 AB09 BA01 CB08 CB22 DA01 DA04 FA01 4K044 AA03 AB10 BA02 BA04 BA06 BA08 BA11 BB01 BB04 BC02 CA04 CA11 CA53 CA62

Claims (12)

[Claims] A step of removing a surface altered layer of the repaired part;
A mixture adhesion step of closely adhering a repair material composed of a composite of a brazing alloy and a flux having a lower melting point than the structural member to a repair surface of the repair section, and a heat sink for heating and melting the brazing alloy to fill the repair section. A method for repairing in-core equipment for a nuclear power plant, comprising: a liquid filling step; and a residue removing step of removing a residue after the combined liquid filling step. 2. The method for repairing in-furnace equipment for a nuclear power plant according to claim 1, further comprising a step of applying a flux to the surface of the repair section before the step of placing the repair material. 3. After repairing the repaired portion, a step of smoothing the surface by machining is included, or a high corrosion resistant layer having the same or better corrosion resistance as the repaired member is formed on the surface of the repaired portion by a thermal spraying method. The method for repairing in-furnace equipment for a nuclear power plant according to claim 1 or 2, comprising a step of performing. 4. The nuclear power plant according to claim 3, further comprising, after the residue removing step, a step of forming a corrosion-resistant layer by a thermal spraying method, and then heating and densifying the thermal sprayed layer by a thermal spraying frame. How to repair furnace equipment. 5. A laser welding method with a heat input of 5 kJ / cm or less or a low heat input TIG on the surface of the repaired part after the residue removing step.
4. The in-furnace equipment for a nuclear power plant according to claim 1, further comprising a step of forming a high corrosion resistant layer equivalent to or more excellent in corrosion resistance to the member to be repaired by a welding method or a low heat input PTA welding method. Repair method. 6. The method according to claim 1, wherein the removal of the deteriorated surface layer of the repair part is performed by a mechanical method such as polishing or blasting. 7. The repair of an in-furnace equipment for a nuclear power plant according to claim 1, wherein the repair material is a paste formed by kneading a brazing alloy powder, a flux, an organic binder and a solvent. Method. 8. The brazing alloy of the repair material is Au, Pt, P
5. Nuclear power according to any one of claims 1 to 4, comprising an alloy of at least one component selected from d, Ag, Ni, Cu, Co, Fe, Cr, P, Si, B and Mn, or a mixture thereof. How to repair furnace equipment for power plants. 9. The method according to claim 1, wherein the flux contains boric acid, borate, and fluoride. 10. The nuclear power generation system according to claim 1, wherein the heating step is performed by local heating such as high-frequency heating, infrared condensing heating, laser heating, or the atmosphere of air or an inert gas. Repair method for furnace equipment for plants. 11. The main component of the alloy powder of the repair material is A
6. The method for repairing in-furnace equipment for a nuclear power plant according to claim 1, wherein the method comprises at least one element selected from the group consisting of u, Pt, Pd, Ni, Co, Cr, P, and Si. 12. The repair of in-furnace equipment for a nuclear power plant according to claim 1, wherein after repairing the repaired portion, a high corrosion resistant austenitic stainless steel is formed as a coating layer on the surface of the repaired portion. Method.