JPH10339041A - Method and device for repairing structure in nuclear reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of cracks in a joined part by fixing a covering plate to a structure in which a crack-shaped defect is generated, flowing the current while the pressure is locally applied, and achieving the joining with the generated resistance heat to reduce the heating time during the execution. SOLUTION: A covering plate 3 is installed on a structure 2, and fixed by a fixing jig 24. A power source, a transformer 12, etc., are installed above the water level, and the execution is remotely achieved using a slide mechanism 26 where an arm 28 or an electrode 10 is movable in a horizontal/vertical direction. A support pillar 27 is fixed above the water level to form a pressure supporting part. The pressure is applied to a contact part of the covering plate 3 immediately below the electrode 10 with the structure 2 by a pressure applying mechanism 14, energization is achieved under the pressure, and a joined part 15 is formed through local fusing by the resistance heat. After one joining is completed, the electrode 10 is successively moved to form continuously joined parts. The resistance welding may be achieved using a rotary electrode. A series of executions are monitored by a monitoring mechanism. Development of cracks attributed to the stress corrosion, etc., can be prevented thereby.

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 a structure and equipment constituting the interior of a reactor pressure vessel during service equipment of a nuclear power plant, and more particularly to a method for repairing a neutron-irradiated and cracked structure. The present invention relates to a repair method and a device for covering a plate material and joining it to a structure in order to enable highly reliable repair of soundness after repair for a structure and equipment in which a defect has occurred.

[0002]

2. Description of the Related Art There is a concern that cracks and aging defects such as stress corrosion cracking may occur in structures and equipment inside a reactor pressure vessel in an environment such as high temperature and high pressure water. Stress corrosion cracking is caused by superposition of deterioration factors such as local composition change of the material itself, stress factors of tensile residual stress applied to the structure by welding, etc., and corrosion environment factors in high temperature and high pressure water. , And cracks grow. If this crack penetrates the above-mentioned structure and equipment, it may lead to a serious accident of the above-mentioned nuclear power plant, and a repair technique for preventing crack penetration of the cracked structure is required.

As a repair technique for preventing such crack penetration, as shown in FIG. 33 (a), an area including a crack-like defect 1 is covered with a plate material 3, and an edge of the plate material 3 and the structure 2 are formed. A method is known in which the defect 1 is isolated from a corrosive environment to prevent the growth of a crack by welding the fillet using the heat input by the arc discharge 6 while adding a filler material 5.

[0004] However, a structure irradiated with neutrons generates He by transmutation of a material constituent element, and contains the generated He inside. In the case where such a material containing He is covered with a plate material as described above and the edge of the plate material and the structure are spot-welded, in a conventional technique such as welding by arc discharge or the like, a filler material is used. In addition, since a heat input amount enough to melt a part of the base material and the plate material is inevitably supplied, as shown in FIGS. 18 to 33, irradiation with neutrons having crack-like defects 1 was performed. When repair is performed on the structure 2 such that the plate 3 is welded to the structure 2 by spot welding, the heat-affected zone 8 on the structure side around the spot weld 7 at the repaired portion generates a new defect 9. There was a risk of becoming a department.

[0005] The above-mentioned problem arises, for example, in the case of austenitic stainless steels as described in Journal of Material Science Vol.
26 (1991), pp. 2063-2070, a material made of the above alloy containing generated He in a state where total neutrons of at least 1.0 × 10 ²⁰ n / m ² are irradiated cumulatively. On the other hand, when welding is performed by applying heat, the weld heat affected zone around the fusion zone is heated to a high temperature and activated by thermal activation.
The diffusion of e into the crystal grain boundaries is facilitated, and the He gas collected at the grain boundaries aggregates to form bubbles having a size of μm unit, so that the strength of the grain boundaries is reduced, and furthermore, after welding, It is based on the recognition that grain boundary cracks occur in the non-molten heat affected zone when a tensile stress accompanying solidification shrinkage is applied.

In the repairing of a structure having a crack-like defect, which is the object of the present invention, in the repairing method according to the prior art in which the plate is covered and the fillet is welded, the plate is brought into close contact with the structure. Heat energy is supplied while supplying filler wire in such a way as to be in contact with both sides of the edge side and the surface of the structure, and the filler wire and plate material are melted and welded to the edge side and the surface of the structure, so they join the structure The heat input may locally increase. Under such welding conditions, as described above, the heat-affected zone is heated to a high temperature and thermal activation facilitates diffusion of He to the crystal grain boundaries, and the heat-affected zone on the structure side causes a new problem. There was a risk of becoming a generation part.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art repair method, and has been developed in consideration of the above problems, such as stainless steel, Ni-based alloy, and low alloy which constitute the interior of a reactor pressure vessel irradiated with neutrons. It is an object of the present invention to provide a sound repair method for a repaired part and a device for repairing crack-like defects such as stress corrosion cracks generated in steel structures and equipment.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a reactor pressure vessel of stainless steel, Ni-base alloy and low alloy steel, which is carried out in a period of service of a nuclear power plant.
A plate material is applied to an area including a portion where a crack-like defect is generated in a structure and an apparatus which has received a neutron irradiation of 0 × 10 ²⁷ n / m ² and has a crack-like defect. ,
A method for repairing an internal structure of a nuclear reactor, characterized in that a pressure is locally applied to a joint surface between the coated plate member and the structure and the energy generated by the generated resistance is joined as a driving force.

The present invention also provides, as a means for performing the above-mentioned joining, an internal structure of a nuclear reactor, characterized in that a current is applied while pressurizing the portion to be joined, and the joint is formed by heating with the generated resistance heat. It is intended to provide a method for repairing a product. Also,
The present invention provides a method for repairing a structure in a nuclear reactor, which comprises performing, as a means for joining by heating with the above-mentioned resistance heat, a coating plate material to the structure by electric resistance welding using a rotating electrode. Things. The present invention also provides a method for repairing a reactor internal structure, characterized in that spot-like welding is performed as means for joining by heating with the resistance heat. Further, the present invention is characterized in that, in the construction in which the spot is joined by heating with the above-described resistance heat, a current is applied to a plurality of electrodes, and a plurality of portions of the structure and the covering plate are joined at the same time. .

Further, the present invention provides a means for performing the above-mentioned joining, in which the joining surface between the structure and the covering plate is mechanically rubbed,
An object of the present invention is to provide a method for repairing an internal structure of a nuclear reactor, characterized in that welding is performed using frictional resistance as a driving force. Also,
The present invention is characterized in that, as means for performing joining using the frictional resistance as a driving force, mechanical vibration is applied to the joint surface while applying pressure to the joint to mechanically rub the joint surface. Further, the present invention provides means for applying the above mechanical vibration to mechanically rub the bonding surface to perform bonding, converting high frequency energy into mechanical vibration by a magnetostriction phenomenon, and converting the obtained mechanical vibration to the bonding portion. And a method for repairing the internal structure of a nuclear reactor, characterized in that the joint surface is mechanically rubbed.

The present invention also provides a method for repairing a reactor internal structure, characterized in that, in the above-mentioned construction, a convex projection is provided on a covering plate material, and the projection is used as a joint surface. . Further, the present invention is characterized in that a concave notch is provided at a contact portion of the structure side with the covering plate material, and the covering plate material is installed and bonded in combination with the projection of the covering plate material.

Further, the present invention is characterized in that, in the above-mentioned construction, the reactor internal structure has means for sealing a reaction generated when pressure is applied by using the internal structure or equipment as a support portion. It is intended to provide a method for repairing a product. Further, the present invention introduces a support pillar between the upper lattice plate of the furnace internal structure and the core support plate as a means for sealing the reaction generated when the above pressure is applied, so that the upper lattice plate and the core support plate are introduced. The present invention provides a method for repairing a reactor internal structure, characterized in that a reaction supported when pressure is applied is sealed by using a pillar supported by a support member as a support portion. Further, the present invention introduces a support pillar between the pressure vessel and the core shroud as a means for sealing a reaction generated when the above pressure is applied, and a pillar supported by the inner surface of the pressure vessel as a support portion. Thus, a reaction generated when pressure is applied is sealed.

The present invention also relates to a repair work for performing the above-mentioned work on a reactor internal structure that is in contact with reactor water, wherein the cover plate material of the structure is provided before the cover plate material is installed in the structural work portion. After performing the work of removing the oxide film in the area including the joining surface with the cover plate, a covering plate is installed, and the above-described joining work is performed. Further, in the present invention, in the above-mentioned repair work of the reactor internal structure, after performing the work of removing an oxide film in a region including a joint surface of the structure with the cover plate material, the structure or the cover plate material is bonded. In the area including the face,
It is characterized in that a surface treatment for finishing the average surface roughness in the range of 0.2 to 10 μm is performed, and after the surface treatment, a covering plate is installed and the above-described joining is performed.

Further, according to the present invention, in the above-mentioned joining work, the covering plate and at least one of the structures have a composition or a crystal structure between the covering plate and a region including a joint surface of the structure. It is characterized in that different intermediate layers are inserted. The present invention also provides a method for repairing a reactor internal structure, wherein a build-up layer or a thermal spray layer is formed as the intermediate layer to be inserted. Further, the present invention is characterized in that the intermediate layer is formed by irradiating a laser beam or an arc beam as a means for forming the cladding layer or the thermal spray layer to be inserted. Further, the present invention is characterized in that a brazing layer is formed as the intermediate layer to be inserted. In addition, the present invention provides a method for preparing the above-mentioned inserted intermediate layer,
at least one of d or Pt is 0.05 to 2.0
It is characterized in that it is contained in the range of wt%. Further, in the present invention, in the joining work, after forming the layer according to claim 9 as a surface layer on the surface of the covering plate material on the side joined to the structure, the joining work according to claims 1 to 8 is performed. It is characterized by performing. In the present invention, in the above-mentioned joining work, the covering plate is installed after forming the layer according to claim 9 as a surface layer on the surface of the structure, and the joining work according to claims 1 to 8 is performed. It is characterized by.

Further, the present invention is characterized in that, in the above-mentioned joining work, a surface molten layer is formed in a region including a portion of the structure surface to be joined with the covering plate material. Further, the present invention is characterized in that as the means for forming the surface molten layer, the surface molten layer is formed by irradiation with laser light or arc light.

Further, the present invention is characterized in that a part or all of the outer peripheral portion of the contact surface between the plate material to be covered and the repaired structure is joined by metal bonding by the above-described construction.

Further, the present invention is characterized in that there is provided a means for sealing the reaction generated when applying pressure for performing the above-mentioned construction. In addition, the present invention, as means for sealing the reaction generated when applying the above pressure,
A pillar supported by the upper lattice plate and the core support plate of the inner structure of the light water reactor in the reaction direction is provided. Further, the present invention provides a repair of a furnace internal structure, comprising a pressure support plate supported in the reaction direction by an inner surface of a pressure vessel as a means for sealing a reaction generated when the pressure is applied. In the device.

The inventors have found that the irradiation amount of all neutrons is 5.0 ×
For the material made of the above alloy in a state of 10 ²⁷ n / m ² or less,
In the construction where the holding time at the temperature causing activation of He is short, the diffusion of He in the non-molten heat-affected zone is suppressed, and it is found that cracks do not occur not only in the molten zone but also in the surrounding heat-affected zone, The present invention has been reached.

Here, as a construction method for joining the structure and the coated plate material, instead of the fillet welding work for melting the filler material to be added, while applying local pressure to the joint surface, physical means is used. According to the construction method in which a resistance is generated in the bonding surface and the relevant part is bonded by mechanical energy such as heat or plastic deformation generated by the generated resistance, by controlling the pressure to be applied and the time for generating the resistance, It is possible to shorten the holding time at the temperature that causes the activation of He described above, and it is possible to perform bonding without generating cracks.

Physical means for applying resistance in a state in which the joint surface is pressurized include generating an electric resistance in the contact surface by flowing an electric current, heating the joint with the generated resistance heat, joining the joint, and mechanical friction. The construction using resistance is mentioned.

First, the principle and operation of a method of joining by passing a current will be described below.

FIG. 28 is a schematic view showing a construction in which an electric current is applied to the structure and the covering plate material while applying a pressure to join them in a spot manner. The electrode A10 comes into contact with the covering plate 3 and the electrode B
11 is in contact with the surface of the structure 2, the two electrodes are electrically connected, and the current flowing between the electrode and the material is controlled by the transformer 12. In addition, a pressure applying mechanism 14 is provided for the electrode A10 in contact with the covering plate 3, so that pressure is locally applied to the contact surface between the plate 3 and the structure 2.
The covering plate 3 just below the electrode A10 by the pressure applying mechanism 14
When pressure is applied to the contact portion between the structure and the structure 2 and a current is applied under pressure, resistance heat is generated by the electric resistance of the contact portion, the coating plate and the structure are locally melted, and the current is stopped or The joint 15 is formed by solidification together with the release of the pressure. The resistance heating value generated here is represented by Q = ρ · j ² · t [J / m ³ ] ρ: specific resistance j: current density t: conduction time Under a constant pressurizing condition, when a large current is applied for a short time, the coating plate and the structure are locally melted to generate heat enough to form the joint 15. Bonding can be performed with a very short energization. In the application by such a short-time energization, the holding time of the temperature region where He is activated is extremely short in the heat-affected zone around the fusion zone, which contributes to He diffusion or bubble formation at grain boundaries. It is possible to perform joining without giving such a thermal effect to the base material.

Further, as shown in FIG. 29, by providing a mechanism 14 for applying pressure to both of the plurality of electrodes, it is possible to simultaneously join the contact surfaces immediately below the plurality of electrodes.

In the above-mentioned method of joining in a spot shape, after the joining at one location is completed, the electrodes are sequentially moved to carry out the joining, and as shown in FIG. Joined without gaps.

Further, as shown in FIG. 30, a continuous joint is easily formed by applying a pressure and applying a current while rotating using the rotating electrode 16 on the disk. In the case of this method, a continuous joint is easily formed by a method of continuously energizing. However, even in a method of intermittently repeating the energization, the joint 15 is continuously formed by controlling the energizing cycle and the construction speed. It is possible to form it.

Next, as an example of construction using mechanical frictional resistance, the principle and operation of a system in which mechanical vibration is applied to generate frictional resistance on the contact surfaces and join the contact surfaces will be described below. FIG. 31 shows construction using ultrasonic oscillation as a means for giving mechanical vibration. When a high-frequency current is applied to the vibrator 17 made of a magnetic material and a coil using the ultrasonic oscillator 18, the vibrator 17 vibrates due to the magnetostriction phenomenon. The generated vibration is increased in amplitude by the resonator 19, and the construction terminal 20 vibrates in the direction of the arrow due to the increased amplitude. Pressure applying mechanism 1 between covering plate 3 and structure 2
The joint surface pressed by 4 generates friction due to the vibration. The contact surface is heated by friction and at the same time undergoes plastic deformation. The plastically deformed surface is brought close to the distance at which the interatomic force acts due to the effect of atom transfer due to heating above the pressure and the recrystallization temperature, and bonds are formed to join the contact surfaces. As the construction conditions, the output and frequency of the ultrasonic wave, the amplified amplitude, the pressing force, etc. are factors,
By setting the working conditions so as not to be heated to a temperature higher than the solution temperature, it is possible to perform joining without causing the formation of bubbles at the grain boundaries of He described above. Also,
Since the construction time in this method is extremely short,
Even if heating to a temperature equal to or higher than the solution temperature partially occurs, bonding that hardly contributes to the formation of bubbles at the grain boundaries of He can be performed.

In the case of joining the covering plate and the structure, 1
After the completion of the joining work at each location, the covering plate is joined to the structure without gaps by sequentially moving the working terminals and performing the work. Further, similarly to the above-described construction by energization, a continuous welded portion can be formed by applying vibration while applying pressure while rotating using a construction terminal on a disk.

Next, a description will be given of the operation of the present invention in which the projections are provided on the covering plate and joined. FIG. 4A is a schematic diagram in which the covering plate 3 provided with the protrusion 21 is installed on the structure 2. As shown in FIGS. 28 to 31, the contact surface immediately below the electrode is pressurized by the pressurizing mechanism, but by using the protrusion 21 as the contact surface, the applied pressure is concentrated, and It is possible to prevent construction failure due to pressure dispersion of the construction. The same effect can be obtained even in the case of the above-described application of applying friction.

FIG. 4B shows the case where the projection 21 is provided on the side of the covering plate. When a thick covering plate is installed, the projection 21 is provided as a contact surface. It has the effect of concentrating pressure.

FIG. 4 (c) is a schematic view in which a concave notch 22 is provided on the structure side, and the covering plate provided with the above-mentioned protrusion is installed in combination with the notch. By using the notch 22 on the structure side and the projection 21 on the cover plate side as the contact surfaces, the applied pressure is concentrated and at the same time, the construction in which the cover plate 3 and the structure 2 are in close contact can be performed.

Here, the above-mentioned construction according to the present invention is based on the premise that pressure is locally applied to the contact surface between the covering plate and the structure. Therefore, when performing the construction in a light water reactor, in order to apply a constant pressure to the contact surface,
It is necessary to seal off the reaction force generated in the application direction in the opposite direction to the application direction. For example, in the construction on the inner surface of the pipe, etc., it is easy to make the opposite side of the construction concerned a pressure support portion, but for a complex-shaped structure in the furnace, in order to seal the reaction force, Means for providing a fulcrum for supporting the pressure applied to the contact surface in the furnace is required.
In the present invention, by using a furnace internal structure or equipment as a support portion, it is possible to use a means for sealing a reaction generated when pressure is applied. For example, in the construction on the inner surface of the shroud 44 of the in-furnace structure shown in FIG. 15, a support pillar 53 is introduced between the upper lattice plate 43 and the core support plate 45 of the in-furnace structure, and the upper lattice plate and the core support By using the pillars supported by the plate as the supporting portions, it is possible to seal off the reaction that occurs when applying pressure. Further, in the construction on the outer surface of the shroud 44 shown in FIG. 18, the support pillar is introduced between the pressure vessel 42 and the shroud 44, and the pillar supported by the inner surface of the pressure vessel 42 is used as a support part, so that the pressure is reduced. It is possible to seal off the reaction that occurs when imparting. Details of the construction will be described later in Examples.

Next, a description will be given of the operation of the above-mentioned joining after removing the oxide film of the structure according to the present invention. Since the internal structure of a light water reactor is located in water, an oxide film may be adhered during operation. If the above-described joining is performed with the oxide film adhered, the electric resistance or the frictional resistance becomes unstable, which may cause a poor construction. Therefore, when performing the above-described construction on the inner structure of the light water reactor, after removing the oxide film in the area including the contact surface of the structure with the coated plate by electric discharge machining or a grinder or emery, the coated plate is installed, It is desirable to perform the above-mentioned joining work. Further, when performing the above-mentioned joining work, it is desirable that the electric resistance or the frictional resistance of the joining surface is appropriately uniformized. In general, when the surface roughness of the contact surface is large, the electric resistance or frictional resistance increases, and bonding can be performed under conditions where the amount of electricity or vibration output is relatively small. It becomes uneven and may cause poor construction. Therefore, in the case of a structure made of stainless steel, a Ni-based alloy, or a low-alloy steel, which is an object of the present invention, the average surface roughness is set to 0.2 to 10 by the above-described means.
After finishing to μm, it is desirable to install a covering plate and perform the above-mentioned joining work.

In the case of performing the above-described joining work, FIG.
As shown in (a), a case where the outside of the joint portion has a gap structure may be considered. Since the gap portion 59 is in contact with the water environment, the gap portion 59 may become a crack generation site such as stress corrosion cracking under the condition that the water quality in the gap is deteriorated. In such a case, as shown in FIG.
By forming 0, it is possible to prevent the occurrence of cracks in the gap 59. For example, Pd
Alternatively, by using a composition containing 0.05 to 2.0 wt% of Pt, the water quality of the gap portion 59 is improved by the hydrogen adsorption effect of the above component, and the occurrence of stress corrosion cracking is prevented. The intermediate layer 60 can be formed by overlaying, spraying, inserting an insert material, or brazing. In the case where the intermediate layer 60 is formed in a furnace, the intermediate layer 60 is formed as a surface layer on the surface of the structure 2, and then the covering plate 3 is installed to perform the above-described joining. When the formation of the intermediate layer is performed outside the furnace, a method in which the intermediate layer 60 is formed on the side where the covering plate 3 is joined, and then the covering plate 3 is installed and the above-described joining is performed is preferable. .

In the case of performing the above-described joining work, FIG.
As shown in (1), the outer periphery of the gap may be metal-bonded to block the gap from reactor water. Irradiation of laser light or arc light with a low heat input is desirable for the formation of the metal bonding portion 61.

Further, when the above-mentioned joining work is performed, FIG.
As shown in (1), if a surface fusion portion is formed in a region including the joining surface of the structure, and then the above-described joining is performed, it is possible to further reduce the cracking susceptibility during the joining.
For forming the surface melting portion 62, it is desirable to irradiate a laser beam or an arc beam with a reduced heat input.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1) Repair work on the internal structure of a nuclear reactor is preferably performed underwater because it is under a gamma ray environment. Hereinafter, as a working example, a concrete working example of the present invention will be described with an experimental example in water using a plate-shaped structure test piece and an example applied to a reactor internal structure. As an embodiment of the present invention,
An example of an experiment in which a covering plate is installed on a structure, and a current is applied while applying pressure to the joining surface to perform joining in a spot-like manner in a horizontal orientation in water, using FIGS. 1 to 7. This will be described below.

1.0 × 10 ²⁰ n / m ² or more 5.0 × 10 ²⁷
A cover plate 3 made of SUS316L stainless steel is placed on a structure 2 made of SUS304 stainless steel in which all neutrons of n / m ² or less have been irradiated and a defect 1 on a crack exists. Here, in this embodiment, as a method of installing the plate material 3,
As shown in FIG. 2, a convex portion 29 is provided on the back side of the plate material 3, and is fixed to the construction portion while holding the convex portion with a fixing jig 24. As a method for holding the convex portion 29, for example, as shown in FIG. 3, the hold portion 32 may be driven using the holding arm 30 to hold the convex portion 29.

Next, as shown in FIG. 1, an apparatus having the electrode 10 and the electrode moving stage 25 is installed. The power supply 13, the transformer 12, and the like are installed on the water surface, and the construction is performed by remote control using a slide mechanism 26 in which the arm 28 or the electrode 10 can move horizontally / vertically. Here, in the present embodiment, the support pillar 27 is fixed on the water surface and serves as a pressure support portion. In addition, the transmission section and the like including the electric wire 23 are constructed by being surrounded by an insulator such as rubber in order to prevent electric leakage.

Next, the arm 28 or the slide mechanism 26
The electrode 10 is set in the relevant section. An electrode (hereinafter, electrode A) 10 to be brought into contact with the covering plate is set on the covering plate portion, and an electrode (hereinafter, electrode B) 11 to be brought into contact with the structure is brought into contact with the surface of the structure. Both electrodes are electrically connected,
The current flowing between the electrodes / materials is controlled by the transformer 12. Further, a pressure applying mechanism 14 is provided for the electrode A10 that comes into contact with the covering plate, so that pressure is locally applied to the contact surface between the plate 3 and the structure 2. In order to increase the pressing force, a projection 21 is provided on the covering plate 3 as shown in FIGS. 4A and 4B, or a notch 22 is formed in the structure 2 as shown in FIG. Is provided, and the plate member 3 may be installed so as to be combined with the protrusion 21 of the covering plate member 3. When pressure is applied to the contact portion between the covering plate 3 and the structure 2 immediately below the electrode A10 by the pressure applying mechanism 14, and when a current is applied under pressure, resistance heat is generated by the electric resistance of the contact portion, and the covering plate and the structure Each of the objects is locally melted to form the joint 15. The above series of operations is monitored by a monitoring mechanism provided in the apparatus.

In this embodiment, a coated plate having a thickness of 10 to 20 mm was installed on a structure 2 having a thickness of 10 to 40 mm, and the structure 2 was installed under the conditions shown in FIG. At the same time that the cover plate 3 was joined, no new cracks occurred in the structure 2. After the completion of one joint,
By successively moving the electrode A10 and applying the same, a continuous joint is formed. Here, when the fixing jig 24 or the like is used as in this embodiment, the vertical direction of the peripheral end of the plate 3 shown in FIG. 2 is first joined, and when the holding of the plate 3 becomes unnecessary. Then, the jig 24 may be removed, and then the horizontal direction may be joined.

With the above construction, as shown in FIG.
The covering plate 3 was joined to the structure 2 without any gap, the crack 1 occurrence part of the structure 2 was isolated from the water environment, and the propagation of the crack due to stress corrosion cracking or the like was prevented.

In this embodiment, the conductivity of water is 1.5 μS / c.
m, the water exerted the insulating effect and did not leak any electricity.However, when there is a risk of electrical leakage such as when the conductivity of water increases, the chamber shown in FIG. It is effective that the inside of the chamber 34 is made an aerial atmosphere, and at the same time, the moisture is removed from the portion to be worked, and the work is dried.

(Embodiment 2) As an embodiment of the present invention, a covering plate is installed on a structure, and a current is applied while applying pressure to a plurality of electrodes on a joint surface to perform spot-like joining. Fig. 8 shows an example of an experiment conducted horizontally in water.
This will be described below with reference to FIGS.

1.0 × 10 ²⁰ n / m ² or more 5.0 × 10 ²⁷
A cover plate made of SUS316L stainless steel is placed on a structure made of SUS304 stainless steel in which all neutrons of n / m ² or less have been irradiated and defects on cracks are present.
Next, an apparatus provided with an electrode and an electrode moving mechanism is installed.

Next, the electrodes are set in the relevant section by the electrode moving mechanism. Except for the mechanism for applying pressure to both of the plurality of electrodes, the construction is the same as in Example 1, but by providing the mechanism 14 for applying pressure to both of the plurality of electrodes, It is possible to join the contact surfaces simultaneously.

FIG. 8 omits the device for driving the electrodes,
FIG. 9 is a three-dimensional view showing only a portion where two electrodes 10 are installed, and FIG. 9 is a schematic cross-sectional view of a state in which devices such as a stage 25 are installed and constructed as viewed from above. In the case of this embodiment, as shown in the same drawing, as in the case of the first embodiment, when the plate material 3 is vertically held while being held by the jig 24, 2
It is possible to simultaneously apply both peripheral ends in the vertical direction by applying pressure and joining the electrodes 10 simultaneously.

In this embodiment, a covering plate having a thickness of 10 to 20 mm was installed on a structure having a plate thickness of 10 to 40 mm, and the construction was carried out under the conditions shown in FIG. At the same time, the structure was not cracked.

After the completion of the joining at one location, the electrodes are sequentially moved to carry out the joining, so that the covering plate 3 is joined to the structure 2 without gaps as shown in FIG.
The generation part was isolated from the water environment, and crack propagation due to stress corrosion cracking and the like was prevented.

(Embodiment 3) As an embodiment of the present invention, a continuous joint is formed by installing a covering plate on a structure and applying current while applying pressure while rotating using electrodes on a disk. An example of an experiment in which a horizontal construction is performed in water in the construction of the method will be described below with reference to FIGS. 11 to 12 and FIG.

FIG. 11 is a schematic cross-sectional view of the construction using the rotating electrodes as viewed from the side, and the pillars, arms and the like shown in FIGS. 1 to 3 are omitted. FIG. 11 is a view in which only one of the electrodes is provided with a pressure applying mechanism and is brought into contact with the plate material. As described in the second embodiment, both electrodes are provided with a rotating electrode provided with a pressure applying mechanism. It is also possible to construct as.

1.0 × 10 ²⁰ n / m ² or more 5.0 × 10 ²⁷
A cover plate 3 made of SUS316L stainless steel is placed on a structure 2 made of SUS304 stainless steel in which all neutrons of n / m ² or less have been irradiated and a defect 1 on a crack exists. Next, the rotating electrode 16 on the disk and the stage 25
A device equipped with is installed.

Next, the electrodes are installed in the relevant section. The rotating electrode A16 to be brought into contact with the covering plate is set in the covering plate portion, and the electrode B11 to be brought into contact with the structure is brought into contact with the surface of the structure. Both electrodes are electrically connected and the current flowing between the electrodes / material is controlled by the transformer. Electrode 1 on disk
By applying electricity while applying pressure while rotating using 6, a continuous joint is formed.

In the case of this method, a continuous joint is easily formed by a method in which the current is continuously supplied. However, even in a method in which the current is intermittently repeated, the joint is controlled by controlling the cycle of the current and the application speed. Can be formed continuously. In the present embodiment, the construction was performed by a method of intermittently repeating energization.

In this embodiment, a covering plate having a thickness of 10 to 20 mm was installed on a structure having a thickness of 10 to 40 mm, and the construction was carried out under the conditions shown in FIG. At the same time that the plate material 3 was joined, no new cracks occurred in the structure 2. As in the first and second embodiments, the vertical direction of the peripheral end of the plate 3 shown in FIG. 2 is first joined, and when the holding of the plate 3 becomes unnecessary, the jig 24
And then rotate the electrode 1 so as to join in the horizontal direction.
As shown in FIG. 6, the covering plate is joined to the structure without any gaps, the cracked parts of the structure are isolated from the water environment, and the cracks due to stress corrosion cracking, etc. Progress was prevented.

Embodiment 4 As an embodiment of the present invention, in a construction in which a covering plate is installed on a structure and mechanical vibration using ultrasonic oscillation is applied to generate frictional resistance on a contact surface and join the structure, An experimental example constructed horizontally in water will be described below with reference to FIGS. 13 to 14 and FIG. 1.0 × 10
SU in which all neutrons of ²⁰ n / m ² or more and 5.0 × 10 ²⁷ n / m ² or less are irradiated and a defect 1 on a crack exists.
A cover plate 3 made of SUS316L stainless steel is installed on the structure 2 made of S304 stainless steel. Next, as shown in FIG. 13, a chamber 38 including a vibrator 17, a resonator 19, a construction terminal 20, and a pressure applying mechanism 14 is installed, and the inside of the chamber 38 is converted into an air atmosphere by a gas injection mechanism 36. The water in the portion to be installed is removed through the nozzle 39 and dried.

The power supply 13, the ultrasonic transmitter 18 and the like are installed on the water surface, and the pillar 27 and the arm 2 are provided in the same manner as in the first embodiment.
8 was carried out by remote control. Here, the transmission section and the like including the electric wire 23 were constructed by being surrounded by an insulator such as rubber in order to prevent electric leakage.

Next, the installation terminal 20 is installed on the portion of the covering plate 3 to be installed. When a high-frequency current of 20 to 50 Hz flows from the ultrasonic transmitter 18 to the vibrator, the vibrator 17 vibrates due to a magnetostriction phenomenon. The generated vibration is increased in amplitude by the resonator 19, and the construction terminal 20 is vibrated by the increased amplitude. Friction is generated by the above-mentioned vibration on the joint surface between the covering plate 3 and the structure 2 immediately below the construction terminal 20 pressurized by the pressurizing mechanism 14. The contact surface is heated by friction and at the same time undergoes plastic deformation. The plastically deformed surface is brought close to the distance at which the interatomic force acts due to the effect of atom transfer by heating to a pressure or a temperature higher than the recrystallization temperature, a bond is generated, and the contact surfaces are joined to form the joint 15. You.

In order to increase the pressing force, a projecting portion 2 is provided on the covering plate 3 as shown in FIGS. 4A and 4B, or a notch is formed in the structure 2 as shown in FIG. 22 may be provided and the plate material may be installed so as to be combined with the protrusion 21 of the covering plate material 3. Further, the above-described series of construction is monitored by a monitoring mechanism.

In this embodiment, a covering plate having a thickness of 2 to 20 mm was installed on a structure having a plate thickness of 10 to 40 mm, and the construction was carried out under the conditions shown in FIG. At the same time, the structure was not cracked.

After the completion of joining at one location, the electrodes are sequentially moved to carry out the joining, so that the covering plate is joined to the structure without gaps as shown in FIG. It was isolated from the environment and crack propagation due to stress corrosion cracking was prevented.

(Embodiment 5) As one embodiment of applying the present invention to a reactor internal structure, an example in which the construction described in Embodiments 1 to 4 is applied to a shroud inner surface or an outer surface of a reactor internal structure will be described. This will be described below with reference to FIGS.

In FIG. 15, the operation is stopped, the upper lid of the pressure vessel 42 is removed, the steam dryer, the steam separator, and the fuel channel are sequentially removed, and the control rod is pulled out from below the pressure vessel. FIG. 9 is a cross-sectional view of the inside of the pressure vessel 42 during repair work in a state where a neutron measurement pipe is also pulled out from below the pressure vessel as necessary and the core is filled with reactor water. Before the repair work, the neutron irradiation equivalent received by the shroud, the position where the defect on the crack occurs, and the area of the area covering the defect are measured. Next, the oxide film on the surface of the construction target portion is mechanically removed from the construction target portion on the inner surface of the shroud 44, and at the same time, the average surface roughness is 0.2 to 10 μm.
Finish in the range of m. This mechanical surface treatment is a process in which sandpaper is mechanically removed by electric rotation to mechanically remove an oxide film on the surface and a metallic luster on the surface.

After the above mechanical surface treatment, the coated plate is placed in the area where the defective portion is covered by using a plate fixing jig.

Next, the construction apparatus having the structure shown in FIGS. 15 and 16 is accessed. The construction device has a structure provided at the tip of a support pillar 53 and a secondary arm 54 having a telescopic mechanism. The secondary arm 54 has a telescopic mechanism 55 in a direction perpendicular to the support pillar, and the tip of the arm has a slide mechanism 5 that the construction device can slide and move.
6 and a rotating mechanism 57 for sliding the vertically introduced slide mechanism in a direction in which the construction apparatus is slid along the joining construction line of the relevant section. With the support pillar 53 and the secondary arm 54, the construction apparatus accesses the construction section where the covering plate 3 and the shroud 44 are joined.

Next, as described in the first to fourth embodiments, the joining work between the covering plate 3 and the inner surface of the shroud 44 is performed. Here, various driving / control operations are performed from inside the remote control room 48. In the remote control room 48 on the operating floor 47, a power supply and a transformer are installed when performing the energization bonding described in the first to third embodiments, and the mechanical vibration bonding described in the fourth embodiment is performed. Is equipped with a power supply and an ultrasonic oscillator. FIGS. 16 and 18 show an example of the second embodiment.
17 shows an apparatus provided with two electrodes each having a pressure applying mechanism, but an apparatus provided with a rotating electrode 16 as shown in FIG. 17 and other apparatuses described in Examples 1 to 4. An apparatus may be provided. In addition, in any case, various control systems, including support pillar introduction, secondary arm drive, electrode or construction terminal position adjustment and drive, applied pressure, construction status monitoring, lighting control, etc. It is installed in a remote control room 48.

In the case of construction using a water exclusion chamber, a chamber is provided at the tip of the secondary arm, and a shield gas is injected into the chamber, monitoring of the construction status, lighting, water exclusion, gas injection, exhaust gas, or the like. Dust, gas flow monitoring,
Gas pressure monitoring, temperature monitoring, humidity monitoring, and the like are also remotely controlled by respective control mechanisms installed in the remote operation room 48.

Here, the joining is performed by applying pressure to the joint surface immediately below the electrode or the construction terminal by the pressure applying mechanism 14. In the case of the in-furnace construction as in the present embodiment, the plate fixing jig is used. Since the joining apparatus including the stage 24 and the stage 25 is accessed by ascending and descending by the crane 49, it is necessary to seal a reaction generated when pressure is applied. The means for supporting the pressure for sealing the reaction in the furnace construction will be described below.

In the case where the covering plate 3 is installed on the inner surface of the shroud 44 and the above-mentioned construction is performed, first, as shown in FIG.
Fix to 3. Next, the support pillar 53 is inserted into the core support plate 45 by passing through the upper lattice plate 43, and is fixed by the upper lattice plate 43 and the core support plate 45. The support pillar 53 fixed by the upper lattice plate 43 and the core support plate 45 has a fixed portion serving as a fulcrum, and serves as a pressure support portion for sealing the reaction. As shown in FIG. The pressure applying mechanism 14 can apply pressure to the portion to be constructed.

In the case where the covering plate 3 is installed on the outer surface of the shroud 44 and the above-mentioned work is performed, first, the plate fixing jig 24 fixes the upper part of the jig to the shroud or peripheral equipment or metal fittings. Next, as shown in FIG. 18, the support pillar 53 provided with the pressure support plate 58 is inserted, the pressure support plate 42 is installed on the inner surface of the pressure vessel 42, and is brought into contact with the inner surface of the pressure vessel 42. The support pillar 53 that has come into contact with the inner surface of the pressure vessel 42 is
Serves as a fulcrum and serves as a pressure supporting portion for sealing the above-mentioned reaction, and in the above-mentioned construction, it is possible to apply pressure to the construction concerned part by a pressure applying mechanism.

The above-mentioned series of construction is always monitored by a construction status monitoring mechanism. Finally, it is confirmed by the monitoring mechanism that there is no crack in the repair work part and its surroundings, and the repair work is completed. (Embodiment 6) As an embodiment of the present invention, the construction in the case where the covering plate material to be installed on the structure is thinned and joined will be described below with reference to FIGS. 1, 19 and 6.

In the construction described in Examples 1 to 5, in order to increase the pressing force, as shown in FIGS.
4 (c), or as shown in FIG. 4 (c), a notch 22 is provided in the structure 2 and the plate 3 is installed so as to be combined with the protrusion 21 of the covering plate 3. As described above, it is also possible to reduce the thickness of the covering plate 3 itself and join it. By reducing the thickness of the covering plate member 3, the energization described in the first to third embodiments and the mechanical vibration described in the fourth embodiment are stabilized, and a construction failure is prevented, so that the reliability of the construction part is further improved. .

In the present embodiment, the construction method described in the first embodiment is applied to a structure 2 having a thickness of 5 to 40 mm and a thickness of 0.5 mm.
A coated plate of 2 to 10 mm is installed, and the construction conditions are as shown in FIG.
As a result of the application under the condition range shown in No. 9, the structure 2 and the covering plate 3 were joined, and at the same time, no new cracks occurred in the structure 2.

With the above construction, as shown in FIG.
The covering plate 3 was joined to the structure 2 without any gap, the crack 1 occurrence part of the structure 2 was isolated from the water environment, and the propagation of the crack due to stress corrosion cracking or the like was prevented.

(Embodiment 7) As an embodiment of the intermediate layer insertion work according to the present invention, after a sprayed layer is formed on the portion where the covering plate of the structure is to be installed, the covering plate is set and the joining is performed. This will be described below with reference to FIGS.

FIG. 20 (a) shows a cross section in which a coating plate is placed and joined after forming a sprayed layer on the portion where the covering plate is to be placed on the structure. SUS304 stainless steel structure 2 irradiated with all neutrons of 1.0 × 10 ²⁰ n / m ² or more and 5.0 × 10 ²⁷ n / m ² or less and having crack defects 1 On the other hand, a sprayed layer 63 having a thickness of about 50 to 200 μm is formed by means such as a plasma arc. The composition (% by weight) of the thermal spray layer 63 is C0-0.02.
%, Si0 to 1.00%, Mn0 to 2.00%, P0
0.0045%, Ni 10.50-15.00%, Cr1
6.50 to 24.00%, Mo 2.00 to 3.00%, N0
~ 0.22%, Nb0 ~ 0.50%, Ti0 ~ 0.50
%, Zr0-0.50%, Pt0-0.50%, Pd0-
It is desirable that the range of 0.50% and the balance of Fe be desirable. However, depending on the material of the structure 2 or the covering plate material 3, the component may not be a stainless steel component, and may contain Pt or Pd.
For example, a brazing component may be used.

Next, the covering plate 3 made of SUS316L stainless steel is installed, and the joining work described in Examples 1 to 6 is performed.

FIG. 20B shows an enlarged cross section of the joint. Depending on the conditions or conditions of the joining work described in Examples 1 to 6, a gap 59 may be formed between the structure 2 near the joint 15 and the covering plate 3 as shown in FIG. In a site having a gap structure in high-temperature water in a light water reactor, the concentration of dissolved oxygen in the gap may increase depending on the condition of the gap, and stress corrosion cracking may occur. In such a case, in this embodiment, the gap 5
Since the thermal sprayed layer 63 having a component containing Pt or Pd having a hydrogen adsorption effect is formed in 9, the concentration of dissolved oxygen in the gap is reduced, and stress corrosion cracking is prevented.

In order to prevent the stress corrosion cracking in the gap near the joint, it is only necessary to form the thermal spray layer 63 only on the joint concerned as shown in FIG. 20. However, as shown in FIG. In the case where the coating plate 3 is joined by forming the thermal spray layer 63 over the entire area of the part 3, even if water infiltrates into the joint part, the development of the stress corrosion cracking of the defect 1 on the initially existing crack does not occur. This is prevented by the above effects.

Further, in this embodiment, since the joining work is performed with the thermal sprayed layer 63 interposed therebetween, the heat input on the structure side becomes smaller,
The diffusion of He is prevented, and the possibility of occurrence of a new crack in the structure 2 is further reduced.

As described above, in this embodiment, the construction in which the thermal spray layer is formed on the surface of the structure, the covering plate material is installed, and the joining is performed has been described. However, as shown in FIG. The same effect is exerted even if the overlay layer 64 having a thickness of about 50 to 500 μm is formed. Further, as shown in FIG. 23, the thickness containing Pt or Pd is about 50 to 50.
Even if a 0-μm plate-shaped insert material 65 is inserted, the same effect as in the present embodiment is exerted.

When it is difficult to form the above-mentioned sprayed layer or build-up layer on the surface of the structure during installation in the furnace, or to install a plate-like insert material, as shown in FIG. Either the above-mentioned thermal sprayed layer 63 is formed on the plate material 3, the build-up layer 64 is formed as shown in FIG. 3B, or the plate-shaped insert material is formed as shown in FIG. 65, the covering plate 3 may be installed in the relevant section, and the joining may be performed.

Further, instead of inserting the intermediate layer as described above, the cover plate 3 itself may be used as the above component. Further, as shown in FIG. 24, a surface modification layer 66 is formed by coating or surface treatment so that the surface of the covering plate 3 in contact with the surface of the structure 2 has the above-mentioned components, and then the covering plate 3 is installed. Then, the joining may be performed. In this case, as a means for forming the surface modified layer 66, a thermal sprayed layer is formed by thermal spraying, a plated layer is formed by plating, a buildup layer is formed by a TIG arc or the like, or an alloy by the above means is used. It is desirable to use a method in which a laser beam is irradiated after the addition of the element to form an alloyed layer. Here, after the surface modified layer 66 is formed, if necessary, a mechanical surface finish is performed before the covering plate material 3 is installed to adjust the surface roughness and the like.
It is desirable to install the joint and perform the joining work.

With the above construction, the covering plate 3 is joined to the structure 2, the portion where the crack 1 occurs in the structure 2 is isolated from the water environment, and the propagation of the crack due to stress corrosion cracking or the like is prevented, and The occurrence of stress corrosion cracking in the later gap was prevented.

(Embodiment 8) As an embodiment of the present invention, a construction in which the surface of a structure is bonded to the above-mentioned coated plate material, a surface molten layer is formed in a region including the relevant portion, and then the coated plate material is installed and joined. This will be described below with reference to FIG.

FIG. 25 is a cross-sectional view showing a section in which a surface melting layer is formed in the portion where the covering plate of the structure is to be placed, and then the covering plate is placed and joined. SUS304 stainless steel structure 2 irradiated with all neutrons of 1.0 × 10 ²⁰ n / m ² or more and 5.0 × 10 ²⁷ n / m ² or less and having crack defects 1 Is irradiated with a laser beam or an arc beam to form a surface molten layer 6 having a depth of about 50 to 500 μm.
Form 2 The amount of heat input required to form the surface molten layer 62 is, for example, 1 × 10 ¹ to 1 × 10 ^{1 using} any one of a TIG arc, a plasma arc, a laser, etc. as an energy source.
It is disclosed in Japanese Patent Application No. 5-79254 that the generation of cracks is prevented when controlled to a range of 1 × 10 ³ J / mm.

Since He is evaporated and reduced in the surface melted layer 62, the surface melted layer 62 is used as a contact surface on the side of the structure at the time of joining the coated plate 3 described in Examples 1 to 7. Crack susceptibility is further reduced.

By the above construction, the covering plate 3 is joined to the structure 2, the portion where the crack 1 of the structure 2 is generated is isolated from the water environment, the propagation of the crack due to stress corrosion cracking or the like is prevented, and at the same time, the joining is performed. The occurrence of cracks in the part was prevented.

(Embodiment 9) As an embodiment of the present invention, a construction in which an outer peripheral portion of a joint portion of a structure surface with the above-mentioned covering plate material is metal-bonded will be described below with reference to FIG.

FIG. 26 shows a cross section in which the outer periphery of the joint between the structure and the covering plate is metal-bonded by local melting. 1.0 × 10 ²⁰ n / m ² or more and 5.0 × 10 ²⁷ n / m ²
Defect 1 on the crack with all the following neutrons irradiated
After the covering plate is joined to the SUS304 stainless steel structure 2 in which is present by the construction described in Example 1 to Example 6 or Example 8, the laser beam or the arc light is applied, and the depth of about 2 mm is applied. A locally fused metal bonding portion 61 of 50 to 500 μm is formed. The amount of heat input required to form the metal joint 61 is, for example, TIG in the same manner as in the eighth embodiment.
It has been found that cracking is prevented when the heat input is controlled in the range of 1 × 10 ¹ to 1 × 10 ³ J / mm using any one of an energy source such as an arc, a plasma arc, and a laser. No. 79254.

By the formation of the metal bonding portion 61 on the outer periphery of the bonding surface, the bonding strength between the structure 2 and the covering plate 3 is improved, and at the same time, the gap described in Embodiment 7 is cut off from the reactor water environment. Crack generation is prevented.

With the above construction, the covering plate 3 is joined to the structure 2, the portion where the crack 1 of the structure 2 is generated is isolated from the water environment, the propagation of the crack due to stress corrosion cracking or the like is prevented, and at the same time, the joining is performed. The strength of the joint was improved, and the occurrence of cracks at the joint was prevented.

[0092]

According to the present invention, it is possible to prevent crack propagation in a structure that has been irradiated with neutrons in a reactor pressure vessel and has a defect on the crack, while preventing cracks during repair. It is possible to prevent the occurrence, and it is effective in preventing accidents due to stress corrosion cracking of a nuclear power plant and prolonging the soundness of the plant.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a construction in which a covering plate material is installed on a structure in water and joined by applying pressure.

FIG. 2 is a diagram showing a situation where a covering plate is installed on a structure.

FIG. 3 is a diagram illustrating a method in which a fixing jig holds a covering plate material.

FIG. 4 is a cross-sectional view in which a covering plate provided with a protrusion is installed on a structure.

FIG. 5 is a diagram showing a range of working conditions of a working in which one electrode is pressurized and energized and joined.

FIG. 6 is a diagram in which the joining of the structure and the covering plate is completed.

FIG. 7 is a cross-sectional view of a construction for joining in a spot shape in water using a water exclusion chamber.

FIG. 8 is a three-dimensional view showing a method of installing two pressure electrodes.

FIG. 9 is a cross-sectional view of a state in which devices such as a stage are installed and constructed as viewed from above.

FIG. 10 is a diagram showing a range of construction conditions for construction in which two electrodes are energized under pressure and joined together.

FIG. 11 is a cross-sectional view of a joining process using pressurizing and energizing using a rotating electrode.

FIG. 12 is a view showing a range of execution conditions for joining by pressurization and energization using a rotating electrode.

FIG. 13 is a cross-sectional view of a joining process using frictional resistance using ultrasonic oscillation.

FIG. 14 is a view showing a range of execution conditions for joining by frictional resistance using ultrasonic oscillation.

FIG. 15 is a cross-sectional view of the construction for accessing the internal structure of the reactor.

FIG. 16 is a cross-sectional view illustrating a construction apparatus provided with a spot electrode when accessing the inner surface of the shroud.

FIG. 17 is a cross-sectional view showing a construction apparatus provided with a rotating electrode when accessing the inner surface of the shroud.

FIG. 18 is a cross-sectional view showing a support pillar and a construction device when accessing an outer surface of the shroud.

FIG. 19 is a diagram showing a range of working conditions for joining by applying a current under pressure when a thin plate is used.

FIG. 20 is a cross-sectional view of a joining section when a thermal sprayed layer is inserted as an intermediate layer.

FIG. 21 is a cross-sectional view of a joining section when a thermal spray layer is formed on the entire area of the plate material installation.

FIG. 22 is a cross-sectional view of a joining section when a build-up layer is inserted as an intermediate layer.

FIG. 23 is a cross-sectional view of a joining section when a plate-like insert material is inserted as an intermediate layer.

FIG. 24 is a cross-sectional view of a joining section when a coated plate having a surface-modified layer is used.

FIG. 25 is a cross-sectional view of a joining section when a surface fusion portion is formed on a structure.

FIG. 26 is a cross-sectional view of a construction portion in which an outer peripheral portion is metal-bonded.

FIG. 27 is a cross-sectional view of a joining process in the case where an intermediate layer is formed in advance on a covering plate material.

FIG. 28 is a cross-sectional view illustrating the principle of joining construction in which a pressure is applied to one electrode.

FIG. 29 is a cross-sectional view illustrating the principle of the joining work in which pressure is applied to two electrodes.

FIG. 30 is a cross-sectional view illustrating the principle of joining construction in which pressurizing and energizing a rotating electrode.

FIG. 31 is a cross-sectional view illustrating the principle of joining construction by frictional resistance using ultrasonic oscillation.

FIG. 32 is a cross-sectional view of a joint having a gap structure.

FIG. 33 is neutron-irradiated according to the prior art;
FIG. 4 is a cross-sectional view showing a structure in which a structure having a defect on a crack is covered with a plate material and which is used for welding a meat fillet by an arc.

[Explanation of symbols]

1 ... crack-like defect, 2 ... structure irradiated with neutrons, 3
... covered plate material, 4 ... arc welding torch, 5 ... filler material,
6 ... arc discharge, 7 ... semi-welded portion, 8 ... weld heat affected zone on the structure side, 9 ... defects generated in the heat affected zone, 10 ... electrodes to be brought into contact with and joined to the plate material, 11 ... on the surface of the structure Electrodes to be contacted, 12 Transformer, 13 Power supply, 14 Pressure applying mechanism, 15 Joint, 16 Rotating electrode, 17 Vibrator, 18 Ultrasonic generator, 19 Resonator, 20 Construction terminal , 21 ... Projection part, 22 ... Notch part, 23 ... Electric wire, 24
... plate fixing jig, 25 ... moving stage, 26 ... slide mechanism, 27 ... support pillar, 28 ... arm, 29 ... convex part of the cover plate, 30 ... hold part drive arm, 31 ... hold part drive arm drive mechanism , 32 ... hold part, 33 ...
Water surface, 34: chamber for electrode access, 35: insulating part,
36: gas injection mechanism, 37: drainage / exhaust gas mechanism, 38:
Ultrasonic vibrator access chamber, 39 ... nozzle, 4
0: chamber drive mechanism, 41: vibrator support mechanism, 42:
Reactor pressure vessel, 43: upper lattice plate, 44: shroud, 45: core support plate, 46: jet pump, 47 ...
Operating floor, 48: Remote control room, 49: Elevating crane, 50: Cover plate fixing jig elevating drive mechanism, 51
… Support pillar lifting drive mechanism for in-furnace construction, 52… Transmission system,
53: support pillar for furnace installation, 54: secondary arm, 55
... Secondary arm drive mechanism, 56 ... Slide mechanism of moving stage, 57 ... Rotating mechanism, 58 ... Pressure support plate, 59 ... Gap, 60 ... Intermediate layer, 61 ... Metal joint part, 62 ... Surface melting layer, 63 ... Thermal spray layer, 64: overlay layer, 65: insert material, 66: surface modification layer.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G21C 19/02 G21C 13/00 X (72) Inventor Toshitaka Satsuda 7-1-1, Omika-cho, Hitachi City, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Inside Hitachi, Ltd. (72) Inventor Mitsuo Nakamura 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Research Laboratory, Ltd. (72) Akira Onuma 7-1-1, Omikamachi, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Tsutomu Onuma 1-1-1, Omikamachi, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Takahiko Kato 3-chome, Sachimachi, Hitachi City, Ibaraki Prefecture No. 1-1 Inside Hitachi, Ltd. Hitachi Plant (72) Inventor Yasukata Tamai 3-1-1 Kochicho, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Junichiro Morisawa 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Prefecture Inside Hitachi, Ltd.Hitachi Plant (72) Inventor Kunihiko Suzuki 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Co., Ltd. Inside the Hitachi Works of Hitachi, Ltd.

Claims (14)

[Claims] In a method for repairing a structural material that has been irradiated with high-energy particle beams constituting a reactor pressure vessel,
When covering the area including the portion to be repaired with the plate material, the pressure is locally applied to the contact surface between the plate material and the structure to be repaired while having a means for supporting the pressure, and to the portion where the pressure is applied. A method for repairing a reactor internal structure, characterized in that the contact surfaces are joined by means of generating thermal energy by applying energy. 2. The means for performing the bonding according to claim 1 includes:
Applying current while applying pressure to the relevant part, heating it with the generated resistance heat and joining it, welding the covering plate to the structure using rotary electrodes, or joining it in a spot shape Characteristic repair method for reactor internals. 3. The construction according to claim 2, wherein current is applied while applying pressure to a plurality of electrodes provided with a pressure applying means, and a plurality of portions of the structure and the covering plate material are joined together. A method for repairing an internal structure of a nuclear reactor, characterized by joining together. 4. The means for performing the bonding according to claim 1 includes:
Mechanically rubs the joint surface between the structure and the cover plate while pressurizing the joining section and joining by frictional resistance. As means for joining by the frictional resistance, mechanical vibration is applied while pressing the joining section. As a means for mechanically rubbing the joining surface by applying the above, or by mechanically rubbing the joining surface by giving the above-mentioned mechanical vibration, the high-frequency energy is converted into mechanical vibration by a magnetostriction phenomenon. A method for repairing an internal structure of a nuclear reactor, characterized in that a given mechanical vibration is given to a joining portion to mechanically rub the joining surface. 5. The construction according to any one of claims 1 to 4, wherein the covering plate is provided with a convex projection, and the projection is used as a joint surface, or at a contact portion with the covering plate on the structure side. A method for repairing a reactor internal structure, wherein a concave notch is provided, and a cover plate material is installed and joined in combination with the projection. 6. The construction according to claim 1, further comprising means for sealing a reaction generated when pressure is applied by using a furnace internal structure or equipment as a support portion, As a means for sealing off the reaction that occurs when imparting, a support pillar is introduced between the upper lattice plate and the core support plate of the light water reactor internal structure to support the pillar supported by the upper lattice plate and the core support plate. By adopting a part, a support pillar is introduced between the pressure vessel and the core shroud as a means for sealing a reaction generated when applying pressure, or as a means for sealing a reaction generated when applying the pressure, the pressure vessel A method for repairing a reactor internal structure, wherein a reaction generated when pressure is applied is sealed by using a pillar supported by an inner surface as a supporting portion. 7. The repair work according to any one of claims 1 to 6 for a reactor internal structure in contact with reactor water,
Before installing the covering plate material in the structure construction pertinent part, after performing the construction to remove the oxide film in the area including the joint surface with the covering plate material of the structure, installing the covering plate material and joining. To repair internal reactor structures. 8. The repair of a structure in a nuclear reactor according to claim 7, wherein after removing an oxide film in a region including a joint surface of the structure with a coated plate material, the structure or the coating is removed. In the region including the joining surface of the plate material, the average surface roughness is 0.2
A method for repairing an internal structure of a nuclear reactor, comprising performing a surface treatment to finish in a range of 10 to 10 μm, and installing a covering plate after the surface treatment. 9. The joining process according to claim 1, wherein
An intermediate layer having a different composition or crystal structure from the coated plate and at least one of the structures is inserted between the coated plate and the region including the bonding surface of the structure, as the intermediate layer, That the build-up layer is formed, that the thermal spray layer is formed as the intermediate layer,
As the means for forming the build-up layer or the sprayed layer, forming the intermediate layer by irradiating laser light or arc light, as the intermediate layer, forming a brazing layer, or a component of the intermediate layer As Pd or P
A method for repairing a reactor internal structure, wherein at least one of t is contained in a range of 0.05 to 2.0 wt%. 10. The joining process according to claim 9, wherein the intermediate layer is formed on the surface of the covering plate on the side to be joined to the structure. A method for repairing a reactor internal structure, which is performed. 11. The joining work according to claim 1, wherein a surface molten layer is formed in a region including a portion of the surface of the structure to be joined to the covering plate material, or the surface of the structure is provided with a surface molten layer. A method for repairing an internal structure of a nuclear reactor, wherein the surface molten layer is formed by irradiating a laser beam or an arc light as a means for forming a molten layer. 12. The method according to claim 1, wherein part or all of the outer peripheral portion of the contact surface between the plate material to be covered and the repaired structure is joined by metal bonding. Characteristic repair method for reactor internals. 13. An apparatus for repairing an in-furnace structure according to any one of claims 1 to 12, further comprising means for closing a reaction generated when pressure is applied. . 14. A pressure support mechanism supported in the reaction direction by an upper lattice plate and a core support plate of a light water reactor internal structure as a means for sealing a reaction generated when applying pressure according to claim 13. An apparatus for repairing a furnace internal structure, comprising: a pressure support mechanism supported by an inner surface of a pressure vessel in the reaction direction as means for providing or sealing a reaction generated when applying pressure.