JP3828139B2 - Structure repair equipment - Google Patents

Description

The present invention relates to a repair apparatus for a structure installed in a reactor pressure vessel, and a processing apparatus for performing laser processing on a structure in water.

The in-core structure of the light water cooled nuclear reactor is made of a material having sufficient corrosion resistance and high temperature strength in a high temperature and high pressure water environment such as austenitic stainless steel or nickel base alloy.

However, non-replaceable parts are exposed to high-temperature and high-pressure environments for a long period of time due to long-term operation of the plant, and core materials such as shrouds are subjected to neutron irradiation. The problem is concerned. In particular, in the vicinity of the welded portion of the internal structure of the furnace, there is a risk of potential stress corrosion cracking because material sensitization and tensile residual stress are formed by welding heat input.

Recently, various material surface modification technologies have been developed as preventive maintenance technology measures in response to the prolonged operation period of plants. As part of this effort, countermeasures have been developed to prevent stress corrosion cracking by actively changing the surface residual stress from tension to compression.

For example, surface residual stress improvement techniques have been developed by methods such as shot peening or water jet peening. Shot peening is a technology that accelerates a steel ball of about 0.3 to 1.2 mm using high-pressure air or centrifugal force, and plastically deforms the surface of the construction part by the kinetic energy of the steel ball to form a compressive residual stress on the surface. .

Water jet peening is a technique in which ultrahigh pressure water of about 1000 atm is injected from the tip of a nozzle to form a compressive residual stress on the surface by a shock wave when the water hammer action and cavitation break. In both cases, the effectiveness against stress corrosion cracking has been proved by construction in water, and some have been put into practical use.

On the other hand, as a surface treatment method of a metal material using a conventional laser, quenching by heating,
There are glazing (amorphization) by annealing, surface solidification, alloying (alloy layer formation), cladding (coating of high melting point material), and impact hardening by instantaneous evaporation. Each of these is a process for controlling the surface hardness of the material, and is intended to improve wear resistance, impact resistance, corrosion resistance, and the like.

In order to check the soundness of the equipment between the shroud and reactor vessel installed in the reactor upper chamber of the light water cooled reactor and the surface of both, an apparatus with an underwater TV camera attached to the tip of the mast or rod, Although it is used for visual inspection, no work is performed to change the surface stress state of the structure.

Further, an underwater swimming type inspection robot for visual inspection with a higher degree of freedom is used.
However, this is also for visual inspection, and no work to change the surface stress state of the structure is performed.

When shot peening is used to improve the surface residual stress of a narrow structure such as an annulus between the shroud and the reactor pressure vessel, complete recovery of the shot is difficult. In addition, when construction is performed in the atmosphere, there are problems such as generation of dust and the like, which is a difficult task.

When working to change the surface stress state of a structure using water jet peening, a jet reaction force is generated. Therefore, an automated device is developed to change the precise surface stress state by remote control in a narrow place. That is a very difficult task.

The present invention has been made in order to solve the above-mentioned problems, and the object thereof is a metal surface that does not require shot collection, does not deteriorate the working environment for dust generation due to shot, and does not require reaction force compensation. Another object of the present invention is to provide a structure repair apparatus capable of improving the stress state of the above and a processing apparatus for irradiating while scanning with a pulse laser beam.

In order to achieve the above object, a repair apparatus for a structure according to the present invention is suspended from the upper part of a reactor pressure vessel with a first wire and passes through the apertures of the upper lattice plate at the upper part of the reactor core. An upper case rotatably mounted on the core support plate of the core, and a foldable arm that expands and folds an arm that is attached to the upper case so as to move up and down in the radial direction of the reactor pressure vessel. An arm device, a repair work device mounting base attached to the tip of the arm, and a second wire suspended from the upper part of the reactor pressure vessel are fixed to the upper surface of the other opening portion of the upper lattice plate. A repair work unit transport device and a pulsed laser beam of visible light that is attached to the repair work unit transport device and delivered to the repair work device mounting base while swinging and scanning a certain range. Shines and having a, a repairing operation apparatus for machining the inner surface of the shroud.

Furthermore, as a preferred aspect of the present invention, the link type arm device further includes a lower case installed on an upper portion of a control rod drive device housing at a lower part of the core .

Alternatively, as a preferred aspect of the present invention, the repair work device includes: a longitudinal sweep unit that sweeps a reflecting mirror that reflects the pulse laser beam transmitted from an optical fiber in the longitudinal direction and the width direction; and a width direction sweep unit; And a drive mechanism for driving these units .

Alternatively, as a preferred embodiment of the present invention, the pulse width of the pulsed laser light output from the laser irradiation apparatus is set to 10 psec or more and 1 μsec or less, and the laser irradiation apparatus further includes:
When the pulsed laser light reaching the surface of the structure is E, the energy per pulse is E, the pulse time width is t, and the laser spot area on the surface of the structure is S, 10 ⁶ <E /
It is set to satisfy the condition of (t × S) <10 ¹² .

Here, the basic principle of the present invention will be briefly described with reference to FIG. 19. FIG.
The moment when the workpiece 2 placed inside is irradiated with the pulse laser beam 3 is schematically shown. FIG. 19B shows the state after the irradiation with the pulse laser beam 3 is finished. The transparent liquid 1 used here may be anything as long as it is transparent to the wavelength of the laser beam.

The pulse laser beam 3 is absorbed on the surface of the workpiece 2 at the moment of irradiation, and only the extreme surface is instantaneously heated and rapidly evaporated to generate a high-temperature and high-pressure plasma 4. Due to the instantaneous ejection of the high-pressure plasma 4, an impact force 5 is applied to the workpiece 2 as a reaction force. The basic phenomenon is that the surface of the workpiece 2 is compressed and plastically deformed by the impact force 5.

FIG. 19B shows that the laser beam 3 has been irradiated and plastic deformation has occurred on the surface of the workpiece 2. Thereby, a compressive residual stress 6 is applied to the surface of the workpiece 2.

In a place where this phenomenon occurs, the transparent liquid 1 has an effect of confining the generated plasma due to its inertial force. In the transparent liquid 1, an impact force that is several tens of times greater than that in the case of irradiation in the air or vacuum is obtained. In addition, the cooling effect of the transparent liquid 1 can minimize the thermal effect due to laser irradiation. The present invention is to leave compressive stress on the workpiece surface of the reactor internal structure in this way.

It is effective for construction to form a coating layer that does not transmit laser light for the purpose of increasing the generation efficiency of plasma 4 and reducing the thermal effect on the construction member when irradiating the pulse laser beam 3. is there.

When the amount of heat input by laser irradiation is large with respect to the material, the surface of the construction part melts or changes in the metal structure, which may cause a tensile residual stress rather than compression on the surface. Further, in order to form a sufficiently large compressive residual stress on the surface of the construction part, it is necessary to secure the density per unit time and unit area of the plasma.

Therefore, when directly irradiating a construction part with a laser, irradiation conditions are limited by the construction part material, and strict construction condition control is required. On the other hand, if a coating layer with an appropriate thickness that does not transmit laser light is formed, the coating layer material not only serves as a plasma supply source, but also serves to reduce the heat input to the construction material as much as possible. Since the construction margin is widened, it is advantageous in terms of actual machine construction.

The material of the coating layer may be any kind of insulator, semiconductor, and metal as long as it absorbs laser light, but metal is advantageous because it is necessary to form a very thin coating layer on the surface of the construction part. As a forming method, any method such as attaching a metal thin film with an adhesive, physical vapor deposition, or coating may be used.

Actually, when laser peening is applied as a preventive maintenance method, the reactor internal structure surface is covered with an oxide film due to long-term operation of the plant. In order to form the surface coating layer with a uniform film thickness, it is necessary to remove the oxide film by means such as grinding in consideration of the adhesion of the film.

When the metal thin film is a low melting point metal such as Al, Sn, In, etc., an electrode of 0.05 to 0.2 mm and facing the vicinity of the laser light irradiation surface is installed, and direct current or laser pulse is applied between this and the workpiece. A synchronized voltage of several tens to several hundreds volts is applied. By irradiating under these conditions, the thermal effect on the material is suppressed as much as possible, and furthermore, since the coating layer material is turned into plasma, the coating layer material does not remain on the surface after the laser irradiation, and the coating material removal step after construction is performed. The process can be simplified because it blows away.

Similarly, the coating layer material may be the same material as the high melting point such as W, Mo, Ta, Nb, Ti, Zr, and Hf, or the in-furnace structure such as stainless steel and Inconel. In that case, 0.03 or more 0.15
It has been experimentally confirmed that the same effect can be obtained by irradiating under the same conditions as described above.

When platinum, gold, palladium, and zinc are coating layer materials, it is expected that not only the residual stress improvement effect by laser peening but also the corrosion resistance improvement effect by the coating layer can be expected by leaving these coating layer materials positively. It is very effective as a measure against stress corrosion cracking.

In this case, the thickness of the coating layer is required to be 0.03 mm or more. However, when the thickness is 0.25 mm or more, sufficient compressive residual stress is not formed on the surface of the construction part, so the upper limit value of the film thickness is 0.25 mm.

It has been experimentally clarified that the same effect can be obtained by using the oxide film formed on the surface of the reactor internal structure as the coating film. In that case, it is not necessary to form a coating layer and not only the process can be simplified, but also the effect of improving the surface residual stress and removing the oxide film by direct laser irradiation can be expected.

Further, although the construction is usually performed in the atmosphere, it is more advantageous in improving residual stress to be performed in a medium such as water that transmits laser. In the case of construction in the atmosphere, high-temperature and high-pressure plasma generated by laser irradiation tends to diverge, but when it is performed in water, it has a plasma confinement effect.

Therefore, the residual stress can be effectively formed in the material by the reaction. When applied to the reactor internal structure, it is effective in the sense that the residual stress improvement effect is promoted by constructing in the reactor water and the reliability of the construction is ensured.

In order to achieve the object of changing the surface residual stress of a metal material, the present invention is a laser processing comprising a pulse laser device and an optical device capable of transmitting and irradiating a laser beam to the surface of the workpiece. It is placed in a transparent liquid and irradiated while changing the irradiation position on the surface of the workpiece, leaving a compressive stress on the surface of the workpiece. Further, the liquid having a good laser transmittance has a radiation shielding effect and is to use highly stable water.

Furthermore, more than 10psec the pulse width of the pulse laser beam, and less 1 .mu.sec, when the energy per pulse of the pulsed laser beam E, the pulse time width t, the laser spot area on the work piece and the S, 10 ⁶ <E / (t × S) <10 ¹² [w / cm 2 ] is to be satisfied.

This limitation is a necessary condition for compressing the residual stress on the material surface. If this condition is not met, sufficient compression cannot be obtained as the residual stress on the surface, or only tensile stress due to thermal effects may remain. There is. Detailed irradiation conditions are determined by the target material, the required residual stress intensity, the depth causing the stress change, the allowable thickness of the heat affected zone, and the like.

In order to obtain the above necessary irradiation conditions, an optical device capable of condensing laser light is provided for the purpose of changing the laser spot area S on the workpiece.

A counter electrode is provided in the vicinity of the laser light irradiation surface, and a voltage of several tens to several hundreds volts synchronized with a direct current or a laser pulse is applied between the electrode and the workpiece.

This is because, depending on the laser irradiation conditions such as the pulse width not being sufficiently short, tensile stress due to thermal effects may remain in the surface layer portion of the material. When the thickness of the extreme surface layer portion is not acceptable, the heat affected zone is removed by laser-controlled discharge between the workpiece laser light irradiation surface and the electrodes disposed in the vicinity thereof.

For the same purpose, a transparent liquid is used as the electrolyte, a workpiece is placed in the electrolyte, a negative electrode is provided opposite the laser light irradiation surface, and this and the workpiece are synchronized with direct current or a laser pulse. By applying the applied voltage of several volts to several tens of volts and performing the electropolishing, it is possible to reliably obtain a surface having a compressive stress remaining.

The present invention relates to a processing part of a jet pump riser brace arm between a shroud of a reactor upper chamber and a reactor vessel, a surface of the arm, a surface modification of a jet pump riser pipe, a jet pump diffuser, etc., a surface of an inner surface of the shroud Replacement of the jet pump diffuser, including modification, surface modification of the CRD housing processing part, decontamination of the partition wall surface at the bottom of the annulus between the shroud and the reactor vessel, disassembly by welding of the jet pump diffuser and assembly by welding Equipment and both surfaces can be repaired remotely, and the life of the equipment in the reactor can be extended.

Forming a coating layer on the work surface to suppress the heat effect on the material as much as possible, effectively generate plasma, and improve the residual stress on the workpiece surface by plasma confinement effect in water efficiently and with high reliability Can be implemented.

Thus, a compressive residual stress can be applied to the surface of the workpiece by the impact force generated by the laser light irradiation, and the construction portion can be processed in detail because of the work by the laser light. In addition, since no reaction force is generated during the operation, an extra load is not applied to the operating device, and it is not necessary to increase the strength of the device, and an easy-to-handle device can be obtained and the working efficiency can be improved.

Furthermore, by making the transparent liquid thermally and chemically stable water, it is possible to more reliably apply compressive residual stress to the surface of the workpiece, and to cover the radioactive material by the radiation shielding effect of water. Safe construction is also possible when using workpieces.

By limiting the laser irradiation conditions, it is possible to reliably leave compressive stress on the workpiece. By reducing the irradiation area with a lens or a condenser mirror, it is possible to irradiate under conditions that allow compressive stress to remain even when the laser output per pulse is insufficient.

According to the present invention, since the stress state of the structure surface in the reactor water in the reactor pressure vessel can be improved, it is possible to suppress the stress corrosion damage of the structural material, thereby prolonging the life of the equipment. It is possible to provide a repair device as a possible surface modification device.

That is, according to the present invention, the repair work device mounted on the repair work unit transport device is delivered below the upper grid plate to the repair work device mounting base attached to the tip of the arm of the link type arm device. By irradiating pulse laser light with such a repair work device, for example, a jet pump riser brace arm between a shroud installed in the reactor upper chamber of a light water cooled reactor and a reactor vessel , Riser pipe, jet pump diffuser surface, inner and outer surfaces of shroud, inner and outer surfaces of shroud support, inner surface of reactor vessel, outer surface of CRD housing, etc. An object repairing device can be realized.

Hereinafter, a first embodiment of a repair apparatus for a reactor internal structure according to the present invention will be described with reference to FIGS. 1 to 7.

In the first embodiment, as shown in FIG. 1, the link-type arm device 13 a is suspended from the upper part of the reactor pressure vessel 7 by the wire 8, and the upper case 16 and the lower case 17 are connected to the upper lattice in the center of the reactor core 9. The upper case 16 is installed on the core support plate 12 through the opening 11 of the plate 10. The upper case 16 of the link type arm device 13a and folding arm 13 is attached, a range of pulse laser light in the visible light in the folding repair work device 14 attached to the end of the arm 13 (laser irradiation device) The present invention relates to an apparatus for processing the inner surface of the shroud 15, for example, while performing irradiation while swinging and scanning each time.

FIG. 1 is a conceptual diagram showing how the inner surface of the shroud 15 according to the first embodiment of the present invention is repaired. A link-type arm device 13a composed of an upper case 16 and a lower case 17 containing a folding arm 13 is hung by a wire 8 from an overhead crane (not shown).
11 and the opening 18 in the core support plate 12 and installed in the control rod drive device housing 19 in the core 9.

As shown in the enlarged view of FIG. 2, the folding arm 13 has a repair device mounting base 20 attached to the tip of the arm 30. An upper case guide device 21 and a lower case guide device 22 are mounted on the upper lattice plate 10 on the upper portion of the upper case 16. The lower case guide device 22 is fixed to the upper lattice plate 10 by fixing legs 23.

The repair work unit transport device 24 is suspended from an overhead crane (not shown) by a wire 8 and fixed to the upper surface of the upper lattice plate 10 by fixing legs 23. The repair work unit transport device 24 includes a repair work device 14 Is mounted and delivered to the repair work device mounting base 20 at the tip of the folding arm 13. In FIG. 1, reference numeral 25 denotes an installation guide device, 26 denotes a partition, 27 denotes a reactor pit, and 28 denotes a lower chamber of the upper lattice plate.

As shown in FIG. 2, the folding arm 13 is configured to extend and contract the arm 30 with an air cylinder 29. The folding arm 13 is also connected to a balancer 33 via a pulley 32 by a wire 31.
Combined with.

The upper case guide device 21 and the lower case guide device 22 are provided with air cylinders 34 and 35, respectively, and a connecting rod 36 is provided between the devices 21 and 22. Reference numeral 37 in FIG.
Reference numeral 38 denotes a combined gear, 39 denotes a motor, and 40 denotes a lower bearing.

Next, the laser spot oscillation scanning type laser peening operation unit 4 will be described with reference to FIGS. FIG. 3 is a longitudinal sectional view of a laser peening operation unit 41 as a laser irradiation apparatus for repairing the inner surface of the shroud 15. The work unit 41 includes a longitudinal direction sweep unit 42, a width direction sweep unit 43, an attachment structure 44, an optical fiber connection structure 45 shown in FIG.

The longitudinal sweep unit 42 has a configuration in which two upper side plate structures 46 are connected to a connecting rod 47 and a screw screw 48, and the screw screw 48 is driven by a first driving device 50 via a combination gear 49. The ball screw structure 52 attached to the pair of left and right second side plate structures 51 and 53 and the screw screw 48 are fitted, and the width direction sweep unit 43 is swept.

The width direction sweep unit 43 connects a pair of left and right second side plate structures 51 and 53 with a connecting rod 54 and a screw screw 55, and drives the screw screw 55 with a second driving device 56 via a combination gear 49. Frame structure
The ball screw structure 58 attached to 57 and the screw screw 55 are fitted together, and the frame structure 57 is swept.

The frame structure 59 includes a condensing reflecting mirror 60, a first reflecting mirror 61, a second reflecting mirror 62, a third reflecting mirror 63, and the like. The optical fiber connection structure 45 is a structure in which a group lens 65 is attached to an end structure 64 with a spacer 67 and a pressing plate 68 via a pressing ring 66.

The optical fiber connection structure 45 is attached to the first side plate structure 46 of the longitudinal sweep unit 42 in a detachable state. The laser beam 70 emitted from the optical fiber 69 is converted into a group lens 71.
The parallel beam is made into a parallel beam, and the distance from the wall 72 is made constant by the legs 73 attached to the longitudinal sweep unit 42 which is focused on the wall 72 by the three reflecting mirrors and the one condensing reflecting mirror 60. Hold.

The attachment structure 74 is a structure that is fixed to the two side plate structures 46 of the longitudinal sweep unit 42 and fits with the repair unit mounting base 20 at the tip of the arm 30 of the folding arm 13.

Next, in the first embodiment, an example of laser spot swing scanning and sawtooth scanning using an XY slide mechanism will be described with reference to FIGS.

FIG. 6 is a conceptual diagram of laser spot swing scanning. Moving the condenser reflector 60 and sweeping in the width direction 75
The concept of the method of sweeping in the longitudinal direction is shown. Although the laser beam spot 78 on the wall 72 is illustrated in a circle shape, a rectangular spot shape is used when spot overlap does not occur.

The opening of the presser plate 68 of the optical fiber connection structure 45 is rectangular and used as an aperture. In the figure, reference numeral 79 denotes a rectangular sweep locus. FIG. 7 shows an example in which the laser spot is scanned in a sawtooth waveform. Reference numeral 80 in the figure denotes a sawtooth wave sweep locus.

Next, the operation of the first embodiment according to the present invention will be described with reference to FIGS. Remove the lid of the reactor pressure vessel 7 of the light water cooled reactor, install a remote reactor work device handling device (not shown) on the floor of the reactor pit 27, and inspect and repair equipment suspended crane (not shown) The upper case 16 containing the folding arm 13 and the lower case 17 connected to the lower end of the upper arm 16 are suspended from the upper part of the reactor pressure vessel 7, and the openings 11 of the upper lattice plate 10 and the core support plate 12 are opened. The holes 18 are sequentially passed, and the lower end of the lower case 17 is fitted into the control rod drive device housing 19 of the core 9 to complete the installation.

The upper case guide device 21 and the lower case guide device 22 can move the upper case 16 and the lower case 17 in the axial direction so that the upper case 16 and the lower case 17 can easily pass through the apertures 11 of the upper lattice plate 10. The upper case 16 and the lower case 17 are attached to the upper lattice plate 10
Rotational alignment within the plane is performed as it passes through the aperture 11.

The lower case guide device 22 is fixed to the upper lattice plate 10 with the fixing legs 23, the lower case 17 is fitted to the control rod drive device housing 19, and the installation is finished.

The folding arm 13 is deployed from the upper case 16 to the upper lattice plate lower chamber 28, and the upper case 16
The upper case 16 to which the foldable arm 13 is attached is rotated via the motor 39 and the assembled gear 38 attached to the inside, and the foldable arm 13 is directed in a predetermined direction.

The air cylinder 29 (see FIG. 2) of the folding arm 13 is driven, the arm 30 is taken in and out in the radial direction, and the repair work device mounting base 20 attached to the tip of the arm 30 is set to a predetermined position in the radial direction. .

The assembled gear 38 is driven by the motor 39, the arm 30 is raised to the vicinity of the upper lattice plate 10, the air cylinder 29 is driven while the upper case 16 is rotated, and the arm 30 is moved in and out in the radial direction.
A repair work device mounting base 20 attached to the tip of the upper grid plate 10 is brought below the opening 11 of the predetermined upper grid plate 10.

The repair work unit 14 is housed in the repair work unit transport device 24 to which the installation guide device 25 is mounted, and is suspended in the reactor pressure vessel 7 by an inspection / repair device suspension crane (not shown), and the upper grid plate Install in 10 apertures 11. The upper grid plate 10 is fixed by fixing legs 23 attached to the installation guide device 25.

The repair work device 14 is pushed out below the repair work unit transport device 24, and the connection structure 53 (see FIG. 4) of the repair work device 14 and the repair work unit mounting base 20 at the tip of the arm 30 of the folding arm 13 are coupled. .

When the connection is completed, the gripping state of the repair work device 14 of the repair work unit transport device 24 is released. When this release is completed, the folding arm 13 is moved three-dimensionally in the upper lattice plate lower chamber 28, the repair work device 14 is brought to a predetermined position of the shroud 15, and repair work is performed.

As the repair work device 14, an inspection / inspection work unit, a welding work unit, an EDM work unit, a grinder work unit, a laser peening work unit 41, or the like is used.

A laser peening work unit or the like is used as the repair work device 14, and the surface modification work is performed so that the surface of the welded portion of the shroud 15 is compressed to a compressive stress state. The surface modification work method using the laser spot oscillating type laser peening work unit 41 will be described below (FIG. 3).
FIG. 4, FIG. 5 and FIG. 6).

The fitting portion of the mounting structure 44 of the laser spot swinging type laser peening unit 41 is coupled to the repair unit mounting base 20 provided at the tip of the arm 30 of the folding arm 13, and the arm 30 is extended to weld the shroud 15. The laser spot oscillating laser peening work unit 41 is moved to a place where tensile stress is generated on the surface with wires, etc.
73 is set at a predetermined position while being pressed against the surface of the shroud 15.

When surface-modifying the weld line portion, the longitudinal direction sweep unit 42 is set in the direction of the weld line, and the width direction sweep unit 43 is set so that the weld portion fits within the sweepable range in the direction perpendicular to the weld line. A copper vapor laser having a repetition rate of 5 KHz is used as the laser light 70. When the optical fiber 69 having a diameter of about 0.3 mm is used, the spot diameter 77 of the laser beam 70 can be reduced to about 0.3 mm by using an optical system.

FIG. 6 is a conceptual diagram of laser spot swing scanning using the XY slide device of the laser peening operation unit 41 in FIG. 3, where X indicates a longitudinal direction sweep unit 42 and Y indicates a width direction sweep unit 43, for example.

The pulse width of the copper vapor laser is about 40nsec, and the irradiation interval of laser light 70 is 200μsec.
Compared with, the irradiation time is negligible. When the sweep 75 in the width direction is performed with the laser beam spot 78 not overlapping (see FIG. 6), the sweep speed in the width direction needs to be about 1.5 m / s.

When the sweep 76 in the longitudinal direction is performed with the laser light spot 78 not overlapping (see FIG. 6), the number of irradiations in the widthwise sweep 75 is multiplied by 200 μsec at a sweep speed of about 1.5 m / s. 0.3
Sweep mm.

When the laser beam spot 78 is circular, when it is swept at a speed of about 1.5 m / s, a range where the laser beam 70 is not irradiated is generated as shown in FIG. When it is necessary to prevent this range from occurring, the sweep speed is set to 1.5 m / s or less so that the laser light spots 78 partially overlap.

Alternatively, if an optical system that makes the beam cross-sectional shape of the laser beam 70 rectangular in the 45 parts of the optical fiber connection structure is used as a laser beam spot 78 with one side of 0.3 mm, a sweep of 1.5 m / s in the longitudinal and width directions is performed. By doing so, it is possible to irradiate the pulse laser beam 70 once in a range of a certain width and length.

This makes it possible to perform surface modification repairs (repairs that change from a tensile stress state to a compressive stress state) in water using a steel vapor laser with a currently available output of about 500 W.

When the surface modification work within a certain range is completed, the arm 30 is slightly shrunk, and the arm 30 is
The laser spot oscillating laser peening unit 41 is installed at a position where the surface modification operation can be continued in the range where the surface modification is completed, and the above operation is repeated.

The sweep 75 in the width direction repeats the motion of rotating the driving device 56 in a certain direction and rotating the driving device 56 in the opposite direction when the sweep of the predetermined width is completed. Although the longitudinal sweep 76 is performed intermittently, it is not necessary to make a constant speed motion as described above.

Next, the effect of the first embodiment will be described. Since it is possible to perform surface modification repair (repair from tensile stress state to compressive stress state) in water using a copper vapor laser that is a visible light laser with a current output of about 500 W, welding of the shroud 15 The operation | work which changes the tensile stress state of a line | wire and the surface into a compressive stress state can be performed in water, and an operator's exposure can be reduced.

Unlike water jet peening, the use of a laser can neglect the occurrence of reaction force during surface modification work, so the structure of the remote handling device can be simple. Unlike shot blast peening, there is no waste that needs to be collected as in water jet peening.

During laser shot peening, since ultrasonic sound is generated, it is possible to monitor the work status and evaluate the work results simultaneously with the surface modification work, and there is no need to prepare a separate device for monitoring and measurement. Efficiency can be increased.

In addition, in the said 1st Example, it suspended with the wire 8 from the upper part of the reactor pressure vessel 7,
The upper lattice plate opening 11 at the center of the core 9 is passed through, and a link type arm device 13 is connected to the core support plate 12.
The shroud 15 is irradiated with a laser beam of visible light while scanning with a certain range with a repair work device 14 (laser irradiation device) attached to the tip of the folding arm 13 of the link type arm device 13a. Can be processed (see FIG. 7).

In this way, the operation of the first embodiment is essentially the same, but as shown in FIGS. 3 and 4, a separating mechanism such as an electromagnetic clutch between the assembled gear 49 and the screw screw 55, and a screw The screw 55 is reversely rotated by a driving source force such as a spring, and the width direction sweep unit 43 is returned to the original position for about 200 μsec, and is moved intermittently by 0.3 mm in the longitudinal direction during that time. Thereafter, the same sweeping operation as in the first embodiment is repeated.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a longitudinal sectional view of a laser spot oscillating scanning type laser peening operation unit 81 using a galvanometer mirror mechanism. The unit 81 includes a longitudinal direction sweep unit 82, a width direction sweep unit 83, an attachment structure 84, an optical fiber connection structure 45, and the like.

The longitudinal sweep unit 82 has a configuration in which two side plate structures 85 are connected by a connecting rod 86 and a screw screw 87, and the screw screw 87 is driven by a driving device 89 via a combination gear 88. The ball screw structure 91 attached to the frame structure 90 and the screw screw 87 are fitted, and the width direction sweep unit 83 is swept.

The width direction sweeping unit 83 includes a condensing reflecting mirror 93, a galvano mirror 94, and a first reflecting mirror 95 in a frame structure 92.
, A driving device 96, a combined gear 97, and the like. The optical fiber connection structure 45 is a structure in which a group lens 71 is attached to an end structure 64 with a spacer 67 and a pressing plate 68 via a pressing ring 66.

The optical fiber connection structure 45 is attached to the side plate structure 85 of the longitudinal sweep unit 82 in a detachable state. The laser beam 70 emitted from the optical fiber 69 is converted into parallel rays by the combined lens 71, irradiated from the first reflecting mirror 95 to the galvano mirror 94, swung in the width direction by the galvano mirror 94, and irradiated to the condensing reflecting mirror 93. Then, the condenser reflector 93 focuses on the wall 72 while swinging in the width direction.

The locus of this spot forms an arc shape as shown in FIG. A leg 73 attached to the longitudinal sweep unit 82 keeps the distance from the wall 72 constant. The mounting structure 84 is fixed to the two side plate structures 85 of the longitudinal sweep unit 82 and is fitted to the repair work unit mounting base 20 at the tip of the arm 30 of the folding arm 13 shown in FIG.

FIG. 11 is a conceptual diagram of the laser beam spot swing scanning using the galvanometer mirror mechanism. Reference numeral 78 indicates the laser beam spots 78 and 98 for the sweep locus, and 99 indicates the swing.

Next, the operation of the second embodiment will be described with reference to FIGS. The second embodiment is suspended from the upper part of the reactor pressure vessel 7 by the wire 8 and passes through the upper lattice plate opening 11 in the center of the core,
A link-type arm device 13a is installed on the core support plate 12, and a galvano mirror 94 is used for each pulse of visible laser light in a fixed range by a repair device 14 (laser irradiation device) attached to the tip of the folding arm 13. The inner surface of the shroud 15 is processed by irradiating the laser spot while swinging scanning.

The operation of the second embodiment is essentially the same as that of the first embodiment, except that the widthwise sweep 75 shown in FIG. 6 and FIG. Then, the sweep locus 79 of the laser beam spot 78 is drawn in an arc shape on the surface of the shroud 15 and is moved intermittently by 0.3 mm in the longitudinal direction. Thereafter, the same sweeping operation as in the first embodiment is repeated (
(See Figure 11). Since the effect of this embodiment is the same as that of the first embodiment, the description thereof is omitted.

Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a front view of a laser spot scanning type laser peening operation unit 100 using a polygon mirror mechanism (indicated by arrows BB in FIG. 13). The laser peening work unit 100 is coupled to the repair work unit attachment 20 at the tip of the arm 30 of the folding arm 13 shown in FIG.

A mounting structure 101, a screw screw 103, and a slide bar 104 are coupled between the two end plate structures 102. The slide bar 104 passes through the moving plate 105, and a screw screw 103 is coupled by a ball screw 106 of the moving plate 105 shown in FIG.

The drive device 107 is operated to rotate the screw screw 103, and the moving plate 105 is slid using the slide bar 104 as a guide. A mounting base 108 is coupled to the moving plate 105 via a large-diameter spring 109. The wheel type leg 73 attached to the mounting base 108 is pressed against the wall surface 72 to set the laser peening unit 100.

The laser beam 70 guided by the optical fiber 69 is converted into a parallel beam by the group lens 110 and is converted into a polarization mirror.
A polygon mirror 113 is guided through the mirror 111 and the mirror 112 and reflected to form an image on the wall 72.

The polygon mirror 113 and the claw 114 are rotated by the actuator 115 to bring the claw 117 and the claw 114 of the cylinder 116 into contact with each other until the contact between the claw 117 and the claw 114 is released against the elastic force of the small-diameter spring 118. And the irradiation of the laser beam 70 onto the wall surface 72 is swept in the width direction.

The sweep in the longitudinal direction is performed by rotating the screw screw 103 by the driving device 107 and moving the moving plate 105 so that the wheeled leg 73 is in close contact with the wall surface 72 and rotated. In the figure
Reference numeral 119 denotes a beam damper, and 120 denotes an actuator mounting structure.

FIG. 13 is a side view of a laser spot scanning type laser peening operation unit 100 using a polygon mirror mechanism (a view taken along the line AA in FIG. 12).

14 (a) and 14 (b) are detailed conceptual views of a laser spot scanning mechanism using a polygon mirror 113. FIG. The polygon mirror 113 and the claw 114 (114a to 111k) are rotated by the actuator 115. With this rotation, the cylinder 116 is pulled up while the claw 114 and the claw 117 are in contact with each other. 118, the structure returns to the original position.

On the other hand, the laser beam 70 is not shown, but has a structure in which irradiation can be switched on and off with a Faraday rotator, a shutter, etc. on the light source side.
The light is reflected by the mirror 112 and the polygon mirror 113 and is applied to the wall surface 72.

Further, the laser beam 70 that has not been reflected by the polarizing mirror 111 is absorbed by the beam damper 119. Although not shown, the beam damper 119 is constantly cooled by a cooler.

FIG. 15 is a conceptual diagram of scanning of the laser beam spot 78 using the polygon mirror 113, and reference numeral 121 indicates a sweep path. FIG. 16 is a conceptual diagram of scanning of the laser beam spot 78 using the polygon mirror 113. Reference numeral 122 denotes a first mirror, 123 denotes a second mirror, and 124 denotes a third mirror.

Next, the function and effect of the third embodiment will be described. That is, in the third embodiment, the reactor pressure vessel 7 is hung by the wire 8 and passed through the upper lattice plate opening 11 at the center of the core 9, and the link type arm device 13 a is attached to the core support plate 12. The laser beam spot 78 is set by using a polygon mirror 113 for each pulse of visible pulsed laser light by a repair work device 14 (laser irradiation device) installed and attached to the tip of the folding arm 13 of the link type arm device 13a. The inner surface of the shroud 15 is processed by irradiation while scanning.

The operational effect of the third embodiment is essentially the same as that of the first embodiment, but the polygon mirror 113 of the polygon mirror is rotated at a constant angular velocity to perform sawtooth sweep, and is synchronized with the high speed of the mirror 112. The origin return operation is performed.

Next, a fourth embodiment according to the present invention will be described with reference to FIGS. FIG. 17 is a conceptual diagram of a laser beam spot swivel scanning type laser peening operation unit 125 using an articulated arm. The laser peening unit 125 includes a swivel structure 126, a slide structure 127,
An optical fiber connection structure 128, an attachment structure 129, and the like are formed, and the attachment structure 129 is coupled to the repair unit attachment 20 at the tip of the arm 30 of the folding arm 13 shown in FIG.

The swivel structure 126 is swung via a combination gear 131 by a driving device 130 attached to the slide structure 127. The swivel structure 126 and the slide structure 127 are coupled via a bearing 132 structure. The mounting structure 129 and the slide structure 127 are combined, and the slide structure 127 is a hydraulic cylinder structure 133 that is hydraulically driven.

An optical fiber connection structure 128 is coupled to the slide structure 127, and a combined lens 134 that converts the laser light 70 from the optical fiber 69 into parallel rays is attached. The parallel light beams are redirected by the third reflecting mirror 135, the second reflecting mirror 136, and the first reflecting mirror 137, and are collected on the surface of the wall 72 by the condensing reflecting mirror 138.

By turning the turning structure 126, a laser beam spot with a small aperture as shown in FIG.
78 sweep traces 139 are drawn, and the slide structure 127 is driven by water pressure to perform the sweep in the longitudinal direction. Figure
18 is a conceptual diagram of laser spot swirl scanning of the apparatus in FIG.

Next, the function and effect of the fourth embodiment will be described. That is, in the fourth embodiment, as shown in FIG. 1, it is suspended from the upper part of the reactor pressure vessel 7 by the wire 8 and passed through the upper lattice plate opening 11 at the center of the reactor core 9. A link-type arm device 13a is installed on the top of the folding-type arm 13a of the link-type arm device 13a. The surface of the shroud 15 is processed by irradiating the laser repeatedly by moving the circular irradiation in the direction and scanning a certain range (see FIGS. 1 and 12).

The operational effects of the fourth embodiment are essentially the same as those of the first embodiment. However, the following points are different. The condensing reflector 138 is rotated at a high speed to sweep the pulsed laser light spot 78 in a circular shape with a small diameter and irradiate the inner surface of the shroud, while moving the circular irradiation in the longitudinal direction using the hydraulic drive cylinder structure 133. Then, the inner surface of the shroud is irradiated and laser is irradiated repeatedly to scan a certain range, and the inner surface of the shroud is processed.

According to the fourth embodiment, there is no influence of an impact or the like at the time of sweeping for sweeping the laser light spot 78 into a circular shape having a minute diameter. Moreover, since the tip structure is cylindrical, the flow resistance of rotation in water is reduced. In addition, since it is possible to make a structure in which the weight is balanced in the axial symmetry of the cylinder, there is no structural problem with respect to high-speed rotation.

Furthermore, since the circular irradiation is moved in the longitudinal direction using a hydraulic drive cylinder, it is not necessary to provide a watertight structure in the longitudinal movement mechanism in water. Therefore, the structure can be simplified, the equipment attached to the tip of the repair work device can be miniaturized, and the structure of the repair work device can be simplified.

Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, as shown in FIG. 1, a reactor 8 is suspended from the upper part of the reactor pressure vessel 7 by wires 8, passed through the upper lattice plate opening 11 at the center of the core 9, and linked to the core support plate 12. Type arm device 13a is installed, and this link type arm device 13a
The XY slide mechanism shown in the first embodiment and the galvanometer mirror shown in the second embodiment, with a repairing device (laser irradiation device) attached to the tip of the folding arm 13 94, the polygon mirror 113 shown in the third embodiment, the notch of the notch shape of the inner surface of the shroud using the scanning of a telescopic arm with a turning mechanism in a small diameter circular shape shown in the fourth embodiment The present invention relates to an apparatus for forming a stop hole in water by repeatedly irradiating a laser beam on the same locus of a tip portion.

The operation of the fifth embodiment is essentially the same as that of the first to fourth embodiments. However, the following points are different. This is the point that a stop hole is formed in water by repeatedly irradiating a laser on a circular locus at the tip of the notch in the inner surface of the shroud.

According to the fifth embodiment, since it is possible to work directly in water, there is no need to use a laser irradiation torch equipped with a water removal mechanism, a stop hole can be easily formed at the tip of the crack, stress concentration is reduced, and the crack is reduced. Progress is restrained and effective in extending the life of nuclear power plants.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the 1st Example of the repair apparatus of the reactor internal structure which concerns on this invention. In FIG. 1, the longitudinal cross-sectional view which shows the detail of a link-type arm apparatus. 1. It is a longitudinal cross-sectional view which shows the laser spot rocking | fluctuation scanning type laser peening working unit using XY slide mechanism used in FIG. 1, and shows the CC arrow direction of FIG. The top view seen from the AA arrow direction in FIG. FIG. 4 is a cross-sectional view cut along the direction of arrows BB in FIG. 3. The laser spot rocking | fluctuation scanning conceptual diagram of XY slide apparatus utilization in FIG. The laser spot sawtooth scanning conceptual diagram of XY slide apparatus utilization in FIG. It is a longitudinal cross-sectional view which shows the laser beam spot rocking | fluctuation scanning type laser peening work unit using a galvano mirror mechanism in 2nd Example based on this invention, and shows the CC arrow direction of FIG. The top view seen from the AA arrow direction in FIG. The cross-sectional view cut | disconnected from the BB arrow direction in FIG. The laser beam spot rocking | fluctuation scanning conceptual diagram using a galvanometer mirror mechanism with the apparatus in FIG. 13 is a front view showing a laser beam spot scanning laser peening operation unit using a polygon mirror mechanism in a third embodiment according to the present invention, and shows a direction of arrows BB in FIG. The side view seen from the AA arrow direction in FIG. (A) is the side view which expands and shows the BB arrow direction in FIG. 13, shows the DD arrow direction of (b), (b) cuts the CC arrow direction of (a). FIG. FIG. 13 is a conceptual diagram showing a first example of laser beam spot sawtooth scanning using the polygon mirror mechanism in FIG. FIG. 13 is a conceptual diagram showing a second example of laser beam spot sawtooth scanning using the polygon mirror mechanism in FIG. The longitudinal cross-sectional view which shows the laser beam spot turning scanning type | mold laser peening operation | work unit using the articulated arm in 4th Example based on this invention. FIG. 18 is a conceptual diagram showing laser beam spot turning scanning using the articulated arm in FIG. (A) is a schematic diagram for demonstrating the principle by a laser peening method, (b) is a schematic diagram which shows the state of a process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent liquid, 2 ... Workpiece, 3 ... Pulse laser beam, 4 ... Plasma, 5 ... Impact force, 6 ...
Compressive residual stress, 7 ... Reactor pressure vessel, 8 ... Wire, 9 ... Core, 10 ... Upper lattice plate, 11 ... Upper lattice plate opening, 12 ... Core support plate, 13 ... Foldable arm, 13a ... Link arm apparatus,
14 ... Repair work device, 15 ... Shroud, 16 ... Upper case, 17 ... Lower case, 18 ... Core support plate opening, 19 ... Control rod drive housing, 20 ... Repair work unit mounting base, 21 ... Upper case guide device 22 ... Lower case guide device, 23 ... Fixing leg, 24 ... Repair unit transport device,
25 ... Installation guide device, 26 ... Bulkhead, 27 ... Reactor pit, 28 ... Upper lattice plate lower chamber, 29 ... Air cylinder, 30 ... Arm, 31 ... Wire, 32 ... Pulley, 33 ... Balancer, 34, 35 ... Air Cylinder, 36
... Connecting rod, 37 ... Upper bearing, 38 ... Built gear, 39 ... Motor, 40 ... Lower bearing, 41 ... Laser peening unit, 42 ... Longitudinal sweep unit, 43 ... Width sweep unit,
44 ... Mounting structure, 45 ... Optical fiber connection structure, 46 ... First side plate structure, 47 ... Connection rod, 48 ... Screw screw, 49 ... Assembly gear, 50 ... First drive unit, 51 ... Second side plate structure, 52 ... Ball screw structure, 53 ... Connection structure, 54 ... Connection rod, 55 ... Screw screw, 56 ... Second drive device, 57 ... Frame structure, 58 ... Ball screw structure, 59 ... Frame structure, 60 ... Condensing reflector, 61 ... 1st reflecting mirror, 62 ... 2nd reflecting mirror, 63 ... 3rd reflecting mirror, 64 ... End structure, 65 ... Assembly lens, 66 ... Holding ring, 67 ... Spacer, 68
... presser plate, 69 ... optical fiber, 70 ... laser light, 71 ... pair lens, 72 ... wall, 73 ... leg, 74 ... mounting structure, 75 ... sweep in width direction, 76 ... sweep in longitudinal direction, 77 ... spot diameter, 78 ... Laser spot, 79 ... Square wave sweep locus, 80 ... Sawtooth locus, 81 ... Laser peening unit (using galvano mirror), 82 ... Longitudinal sweep unit, 83 ... Width direction sweep unit, 84 ... Mounting structure, 85 ... 2 side plates, 86 ... connecting rod, 87 ... screw screw, 88 ... assembled gear, 89 ... driving device,
90 ... Frame structure, 91 ... Ball screw structure, 92 ... Frame structure, 93 ... Condensing reflector, 94 ... Galvano mirror,
95 ... First reflecting mirror, 96 ... Drive device, 97 ... Built gear, 98 ... Sweep trajectory, 99 ... Oscillation, 100 ... Laser peening unit (using polygon mirror), 101 ... Mounting structure, 102 ... Two edges Plate structure, 103 ... Screw screw, 104 ... Slide rod, 105 ... Moving plate, 106 ... Ball screw, 107
... Drive device, 108 ... Mounting base, 109 ... Large spring, 110 ... Complement lens, 111 ... Polarizing mirror, 112 ... Mirror, 113 ... Polygon mirror, 114 ... Nail, 115 ... Actuator, 116 ... Cylinder, 117 ... Claw, 118 ... Small diameter spring, 119 ... Beam damper, 120 ... Actuator mounting structure, 121 ... Sweep trajectory, 122 ... First mirror, 123 ... Second mirror, 124 ...
Third mirror 125 ... Laser peening unit (using multi-joint arm), 126 ... Swivel structure, 127 ... Slide structure, 128 ... Optical fiber connection structure, 129 ... Mounting structure, 130 ... Drive device, 131 ... Built gear, 132 ... Bearing, 133 ... Hydraulic cylinder structure, 134 ... Assembly lens, 135
... 3rd reflecting mirror, 136 ... 2nd reflecting mirror, 137 ... 1st reflecting mirror, 138 ... Condensing reflecting mirror, 139 ... Sweep locus.

Claims (5)

An upper case that is suspended from the upper part of the reactor pressure vessel with a first wire and passes through the apertures of the upper lattice plate at the upper part of the core and is rotatably installed on the core support plate in the middle part of the core. A link-type arm device including a foldable arm that is attached to be movable up and down and expands and folds an arm that moves in and out in a radial direction of the reactor pressure vessel;
Repair work equipment mounting base attached to the tip of this arm;
A repair work unit transporting device that is suspended from the top of the reactor pressure vessel with a second wire and fixed to the upper surface of the other aperture of the upper lattice plate;
A repair work device for processing the inner surface of the reactor shroud by irradiating a pulse laser beam of visible light while oscillating and scanning a fixed range at a time, which is attached to the repair work unit transfer device and delivered to the repair work device mounting base. When,
Repair device of a structure, characterized in that it comprises a. 2. The repair apparatus for a structure according to claim 1, wherein the link type arm device further includes a lower case installed on an upper portion of a control rod drive device housing below the core . The repair work device includes a longitudinal direction sweep unit and a width direction sweep unit that sweep a reflecting mirror that reflects the pulse laser beam sent from an optical fiber in the longitudinal direction and the width direction, and a drive mechanism that drives these units. The apparatus for repairing a structure according to claim 1, comprising: 2. The repair apparatus for a structure according to claim 1 , wherein a pulse width of the pulse laser beam used in the repair work apparatus is set to 10 psec or more and 1 [mu] sec or less . When the pulse laser beam used in the repair work apparatus has an energy per pulse as E, a pulse time width as t, and a laser spot area on the surface of the structure as S, 10 ⁶ <E / (t × S) <10 ¹² The structure repairing device according to claim 1, wherein the repairing device is configured to satisfy the following condition.

Images