JPH05333188A - Reactor inspection/repairing method and device - Google Patents

Abstract

PURPOSE:To provide the method and device capable of concurrently inspecting the inside of a reactor core shroud. CONSTITUTION:An inspection apparatus, a repairing tool, and their installation jigs or assembly parts formed in size to be inserted into openings 3a, 4a of an upper lattice plate 3 or a core support plate 4 are prepared. Installation jigs 8 or assembly parts are hung into a core shroud 2 with a crane 5 from above a reactor vessel 1. They are assembled in the core shroud 2 to install the installation jigs 8. The inspection apparatus and the repairing tool are installed on the installation jigs 8 to inspect and repair the inside of the core shroud 2. A remote control swimming robot 9 having a thrust means is used for support via pressing, holding, and positioning actions during the process to insert the installation jigs 8, inspection apparatus, repairing tool or their assembly parts into the opening sections 3a, 4a of the upper lattice plate 3 or the core support plate 4 and the process to assemble or install them in the core shroud 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor inspection / repair method and apparatus for inspecting and repairing the inside of a core shroud of a light water reactor.

[0002]

2. Description of the Related Art Conventionally, when performing a soundness inspection on the inside of a core shroud installed in an upper chamber of a light water reactor, an underwater television camera or the like is attached to the tip of a mast or a rod hung from above the reactor vessel. Visual inspections are performed using the attached device.

An underwater swimming robot for inspection is used,
It is also known to perform visual inspection with a higher degree of freedom.

However, conventionally, in any case, only inspection is performed, and there is no known technique for simultaneously performing repair of a defective portion found by inspection in association with inspection. ..

[0005]

The reason why the conventional defect repair is not performed simultaneously in connection with inspection is that the upper lattice plate and the core support plate are arranged in the core shroud. It is troublesome to hang the tool through the opening of the upper lattice plate, and it is necessary to hold the jig in various postures during repair, and it is necessary to keep the jig against the reaction force during repair. It may be necessary to support with a certain force or more, but it is considered that the device configuration for that purpose is troublesome.

The present invention overcomes such conventional problems, and not only inspects the inside of the core shroud in the reactor vessel of a light water reactor, but also repairs the defective portion found by the inspection simultaneously with the inspection. It is an object of the present invention to provide a method and apparatus for in-reactor inspection / repair that can be carried out in a routine manner and thereby can efficiently perform repairs at regular inspections by remote control.

[0007]

In order to achieve the above-mentioned object, the method for inspecting and repairing in a nuclear reactor according to the present invention is an inner side of a core shroud of a reactor vessel provided with an upper lattice plate and a core support plate. Is a method for inspecting and repairing with the fuel rods and control rods removed, wherein the inspection tool and repairing jig are pre-sized to be inserted into the openings of the upper lattice plate or core support plate. And these installation jigs or their assembly parts are prepared.First, the installation jigs or their assembly parts are suspended from above the reactor vessel by a crane in the core shroud, and these are assembled in the core shroud for installation repair. After installing the tool, inspecting and repairing the inside of the core shroud by installing inspection tools and repair jigs on the installation jig, at that time, the installation jig,
In the process of inserting inspection tools, repair jigs or their assembly parts into the openings of the upper grid plate or core support plate, and in the process of assembling or installing these in the core shroud, there is a remote-controlled swimmer having thrust means. It is characterized in that the robot is assisted by pressing, gripping and other positioning operations.

Further, the in-reactor inspection / repair device according to the present invention is such that the lower end is removably installed in the control rod drive mechanism housing in the lower part of the reactor vessel and the upper end is the upper lattice plate in the core shroud of the reactor vessel. An installation jig consisting of a plurality of columns standing upright in the lower chamber, and a traveling rail assembled to the upper ends of the columns and formed in a ring shape concentric with the core shroud, and detachably supported on the traveling rails of the installation jig. Inspection tool and repair jig, a hoisting crane and a robot handling device provided at a position facing the core shroud above the reactor vessel, and the inside of the core shroud pulled out from the robot handling device via a cable. Is inserted into the installation jig by the crane,
A swivel robot having a propulsion means for supporting the positioning of the inspection tool or the repair jig, and the installation jig,
The inspection tool, the repair jig, and the parts for assembling them are characterized in that they can be inserted into the openings of the upper lattice plate or the core support plate, respectively.

In the reactor inspection / repair device, as the repair jigs, cleaning jigs, grinding or cutting jigs, drilling jigs, surface modifying jigs, welding jigs are used. Tools or jigs for fastening hole blockers are applied.

[0010]

According to the method of the present invention, an inspection tool, a repair jig, and their installation jigs or assembly parts thereof, which are configured to be inserted through the openings of the upper lattice plate or the core support plate, are used, Since these are suspended and assembled in the core shroud with the aid of a crane and a swimming-type robot, even if an upper lattice plate or core support plate is placed in the core shroud, it should be hung through the opening. Can be done easily and reliably.

Further, according to the apparatus of the present invention, a plurality of installation jigs are detachably installed in the control rod drive mechanism housing and the upper ends thereof stand upright in the lower chamber of the upper lattice plate in the core shroud of the reactor vessel. Of the column, and the traveling rail that is assembled to the upper end of this column and is configured in the shape of a ring that is concentric with the core shroud, so that the installation jig supports the inspection tool and the repair jig.
Tool support etc. during inspection and repair are stable, various postures can be easily set, and more than a certain amount of tool holding force is given against reaction force during repair.

Therefore, according to the present invention, the inside of the core shroud can be inspected, and the defective portion found by the inspection can be efficiently repaired by remote control.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the inspection / repair method and apparatus for a nuclear reactor according to the present invention will be described below with reference to the drawings.

First, the structure of the inspection / repair device in the reactor will be described.

1 to 4 show the state of the core at the time of inspecting and repairing the boiling water reactor, that is, the core from which the fuel rods and control rods have been removed, and its auxiliary equipment and the like. An upper lattice plate 3 and a core support plate 4 are provided above and below the core shroud 2 installed in the reactor pressure vessel 1. As shown in FIG. 2, the upper end of the control rod drive mechanism housing 1b faces below the core support plate 4.

A hoisting crane 5 and a robot handling device 6 are provided above the reactor pressure vessel 1, that is, on the floor of the reactor pit 1a so as to face the core shroud 2. The hoisting crane 5 can swivel and ascend / descend on a horizontal plane, and suspends the installation jig 8 and the like via a wire 7.

As shown in FIGS. 1 to 4, the robot handling device 6 guides a robot 9 for remote operation via a cable 10. The robot handling device 6 has a magazine portion 11 and a winding portion 12 of the cable 10, The base end portion 10a is electrically connected to a remote scanning unit (not shown). FIG. 1 shows a state in which a single robot 9 is used, and FIG. 2 shows a state in which a plurality of robots 9 are used. In addition, the winding portion 12 is a belt 13
It is configured to have a hoisting wheel 14 and a holder 15 that are driven by. Further, the cable 10 is provided with a float 16 and is held so as not to sag in water.

The robot 9 is appropriately sized according to the application, and the one used in the upper lattice plate lower chamber 17 is of a size that can be inserted into the opening 3a of the upper lattice plate 3 and has a core supporting plate lower chamber. The size 18 is large enough to be inserted into the opening 4a of the core support plate 4.

5 to 9 show a configuration example of the robot 9. This robot 9 has a shape of a submersible boat and has a case 19
The three screws 20 provided at the rear part perform forward / backward movement and swing left / right and up / down, and the screw 22 provided in a hole 21 horizontally penetrating the body of the case 19 performs left / right translation and further vertically. Translation in the vertical direction by rotation of the screw 24 provided in the two through holes 23 in the same direction,
In addition, the rotation around the axis of the same portion is performed by the reverse rotation.

Then, two CCDs are provided at the front of the case 19.
A camera 25 is provided so that it can be swung in a horizontal plane by an ultrasonic motor 26, which enables visual recognition of an object and distance measurement by triangulation, and a lamp 27 and a reflector for illuminating the object. 28 is provided. The CCD camera 25 and the lamp 27
Etc. are covered by a transparent cover 29.

A contact metal fitting 30 having a concave front surface is provided on the front portion of the case 19, and a concave portion 30a of the contact metal fitting 30 moves and positions the contact object by contact holding or pressing. And so on.

FIG. 10 shows another example of the robot 9. In this example, the contact fitting 30 is made of a shape memory alloy, and can be deformed into a set shape by being heated to a predetermined temperature by electric heating together with a rod 31 made of the same material and arranged in close proximity. For example, a grip shape like a human hand is stored, and an object can be detachably held.

11 to 27 show the structure of an installation jig installed in the shroud and the structures of inspection tools, repair jigs and the like installed on the installation jig, together with necessary operations.

11 to 16 show a mounting jig 32. The installation jig 32 is an assembly part having a size that allows the openings 3a of the upper grid plate 3 and the openings 4a of the core support plate 4 to be inserted, that is, a plurality of columns 33 and a traveling rail supported by the columns 33. 34 and 34 so that they can be assembled.

As shown in FIG. 11, the support column 33 is removably installed in the control rod drive mechanism housing 1b whose lower end projects below the reactor pressure vessel 1, and whose upper end is below the upper lattice plate in the core shroud 2. It is configured to stand in the chamber 17. In addition, in order to obtain a required installation strength, a plurality of adjoining columns 33 (a central column 33a and a column 33b around it) are connected laterally. That is, as shown in FIG. 12, an engaging groove 35 formed of a dovetail groove or the like is provided at the outer peripheral upper end portion of each of the columns 33a.
As shown in FIG. 16, the support columns 33 are connected to each other by a connecting piece 36 having a T-shaped end cross-sectional shape that is fitted to.

The traveling rail 34 has a gear portion 3 on the outer peripheral surface.
As shown in FIG. 16, it has a plurality of divided rail parts 34a. Each rail part 34a is fitted with a mounting hole 38 formed in the rail part 34a into a projection 39 projecting to the upper end of the support column 33, and is fixed by a fastener not shown.

17 to 24 show specific examples of inspection tools and repair jigs.

17 and 18 show an EDM electrode unit 40 as a repair jig. The EDM electrode unit 40 is installed on the traveling rail 34 via a carriage 41. That is, the EDM servomotor 44 is mounted on the mounting seat 43 having the positioning hole 42 for the carriage 41, and the EDM servomotor 44 is used to mount the electrode 4
5 is moved in the axial direction to perform the boring process for the core shroud 2, and the bogie 41 moves the traveling rail 34.
The processing is performed while moving along.

19 and 20 show the grinder unit 46. The grinder unit 46 is detachably attached to the magnet 48 of the carriage 41 via an attachment jig 47. Then, the air sent from the air hose 49 drives the air motor 50 to rotate the grindstone 51,
The electric motors 52a and 52b rotate the air motor 50 around the axis and perform biaxial movement in a direction parallel to the axis while performing surface grinding.

21 and 22 show a shot blast surface modification unit 53. The structure for mounting the shot blast surface modification unit 53 on the carriage 41 is as follows.
The same as above. Since this shot blast surface modification unit 53 is used in water, the air guided by the air hose 54 is blown from the air nozzle 54a to the inner surface of the core shroud 2, and the water is sucked from the suction hose 55 to be locally eliminated. The shot blasting action from the shot blast hose 56 is performed on the shroud surface from which water has been removed by the blast nozzle 56a, and the surface is thereby modified.

FIG. 23 shows a laser modified surface unit 57. The support structure is the same as above. The laser-modified surface unit 57 has a laser irradiation fiber 58, a visual fiber 59 for detecting irradiation conditions, and a proximity sensor 60 for measuring a distance from the shroud surface.
The shroud surface is modified by being driven by a motor 52a in the vertical direction of the reactor pressure vessel 1. Although not shown, a lens whose focal length can be controlled by remote control is provided at the tip of the laser irradiation fiber 58 in order to adjust the modification conditions. The laser surface modification work is performed in air.

FIG. 24 shows a TIG melting surface reforming unit 61.
Is shown. This TIG melting surface modification unit 61
Is a torch 62 and an ultraviolet filter 6 for monitoring the working condition.
3 and a visual fiber 63. The shroud surface is melt-modified by being driven by the motor 52a in the upward direction of the reactor pressure vessel 1. In addition,
TIG welding is also done in air.

Next, the inspection / repair method inside the reactor will be described.

First, after removing the lid of the reactor pressure vessel 1, the hoisting crane 5 and the robot handling device 6 are installed on the floor surface of the reactor pit 1a. Then, the support crane 33 is suspended by the suspension crane 5, and the robot 9 is suspended by the robot handling device 6.

As shown in FIG. 1 and FIG.
The robot is lowered through the opening 3a of the upper lattice plate 3 and the opening 4a of the core support plate 4, and the robot assists the positioning during the insertion.

When suspending the support column 33, as shown in FIG.
As shown in FIG. 3, a hook 72 driven by an air cylinder 71 provided on a column installation jig 70 is used to grip the projection 73 attached to the upper end of the column 33, or as shown in FIG. A method of inserting the locking projection 75 capable of moving forward and backward of the support fixture 70 into the opened hole 74, or FIG.
As shown in, various methods such as a method of directly fitting the suspension jig 77 with an air cylinder into the hole 76 at the upper end of the column 33 can be applied.

The lower end of the lowered column 33 is fitted and fixed to the upper end of the control rod drive mechanism housing 1b as shown in FIG. Also in this case, as shown in FIG. 2, the robot 9 supports the positioning work at the fitting position.

When connecting a plurality of columns 33, as shown in FIGS. 13 to 15, the air cylinder 80 is used.
The connection piece 36 is hung by a hanging jig 81 with
The support groove is engaged with the engagement groove 35. The robot 9 also assists in this connection.

Next, the traveling rail 34 is attached to the column 33. As shown in FIG. 16, this work is performed by the lifting crane 5
The rail hanging jig 90 attached to the wire 7 is used.
The rail suspension jig 90 is configured such that, for example, a U-shaped support tool 92 is attached to a shaft 91 that can be rotated by a built-in motor, and an air cylinder 93 is incorporated in the support tool 92. Then, the rail 92a is supported by the support 92.
Is squeezed, and is hung at a predetermined support position while being pressed and held by the air cylinder 93. Then, the mounting hole 38 of the rail component 34 a is fitted and fixed to the protrusion 39 of the support column 33. This is done over the entire circumference. In this case also, the robot 9 provides support.

Therefore, rail equipment is assembled in the lower chamber 17 of the upper lattice plate with the assistance of the robot 9, and the traveling rail 34 laid there is inspected or suspended by the crane 5 for repair or repair. The various units as tools, that is, the EDM electrode unit 40, the grinder unit 46, the shot blast surface modification unit 53, the laser modification unit 57, the TIG melting surface modification unit 6
1 and the like are similarly mounted with the support of the robot 9, and are replaced if necessary.

The inspection / repair is first carried out by a conventional inspection unit such as a television camera (not shown) or other optical equipment, or mounted on the traveling rail 43.

When an abnormality is found in the core shroud 2 by inspection, the various units 40, 46, 5
3, 57 and 61 perform repair work such as cleaning, grinding or cutting, drilling, surface modification, welding or hole blocking.

After that, inspection equipment is installed on the traveling rail to inspect the repaired portion. From these inspections and repairs,
A series of work up to the inspection is continuously performed, and the work efficiency can be improved.

25 to 27 exemplify the repairing action when a defect such as a crack is found on the shroud surface.

As shown in FIG. 25A, short defects 90
If a is found, first the EDM electrode unit 40
A hole of a size large enough to remove the defect G by using the EDM
The processing hole 91 is opened, and the plug 92 is mechanically attached thereto.

Further, as shown in FIG. 25B, in the case of a long defect 90b, EDM electrode units 40 are used at both ends of the defect 90b, and EDM as a stop hole is formed.
The processing holes 91 are opened, and the plugs 92 are mechanically attached to them.

As shown in FIGS. 26 and 27, the plug 92 has a plug body 92a composed of a hook portion 93, a shaft portion 94, a stopper portion 95 and a bolt portion 96,
A collar portion 9 that is screwed into the bolt portion 96 of the plug body 92a.
6 and a nut 97. The EDM processed hole 91 has a circular portion 91a, a long hole portion 91b, and a circumferential step portion 91c.

To close the hole, the hook portion 93 of the plug body 92a may be inserted into the elongated hole portion 91 of the EDM processed hole 91, and then the nut 97 may be tightened. That is, with the nut 97 rotated in the right-hand screw direction until the flange portion 96 contacts the surface of the shroud 2, the stopper portion 95 abuts on the circumferential step portion 91c of the EDM processed hole 91, and the plug body 92a is, for example, as shown in FIG. Stop at 90 ° rotation as shown in. Therefore, if the nut 97 is further rotated thereafter, a fixed amount of tightening is performed. After this, welding is performed to prevent the nut from rotating.

According to this embodiment, various units 40, 46, 53, 57, 61 and their installation jigs which are sized so that they can be inserted into the openings 3a, 4a of the upper lattice plate 3 or the core support plate 4 are installed. 8 is suspended by the crane 5 and supported by the swimming-type robot 9 to be suspended and assembled in the core shroud 2. Therefore, even if the upper lattice plate 3 and the core support plate 4 are arranged in the core shroud 2, the opening portion 3a, 4a
It can be easily and surely hung through.

The lower end of the installation jig 8 is removably installed in the control rod drive mechanism housing 1b, and the upper end of the installation jig 8 is in the core shroud 2 of the reactor pressure vessel 1 and is in the lower chamber 1 of the upper lattice plate.
7, a plurality of support columns 33 standing upright, and a traveling rail 34 assembled on the upper ends of the support columns 33 and formed in a ring shape concentric with the core shroud 2, and the installation jig 8 is used for inspection tools and various repair units. 40, 46,
Since it is designed to support 53, 57, 61,
Repairs and inspections can be performed continuously and efficiently.

Although the above-mentioned embodiment is applied to the boiling water reactor, it is of course applicable to other light water reactors such as a pressurized water reactor.

As for the inspection and repair jigs and tools, various jigs and tools other than those shown in the above embodiment can be used.

[0053]

As described above, according to the present invention, not only the inspection of the inside of the core shroud in the reactor vessel of the light water reactor but also the repair of the defective portion found by the inspection is performed simultaneously with the inspection. It is possible to carry out the operation, and thereby, the effect that the repair at the time of the periodic inspection and the like can be efficiently performed by the remote operation is exhibited.

[Brief description of drawings]

FIG. 1 is an overall view showing a core part for explaining an embodiment of the present invention.

FIG. 2 is an overall view of a core portion showing an operation different from that in FIG.

FIG. 3 is an enlarged view of an upper portion of a core according to the same embodiment.

FIG. 4 is a plan view of FIG.

FIG. 5 is a sectional view showing an example of a robot according to the same embodiment.

6 is a cross-sectional view taken along the line AA of FIG.

7 is a sectional view taken along line BB of FIG.

8 is a cross-sectional view taken along the line CC of FIG.

9 is a view on arrow D-D of FIG. 6;

FIG. 10 is a sectional view showing another example of a robot.

FIG. 11 is a diagram showing a state in which a support column is installed.

FIG. 12 is a diagram showing a configuration of a support column.

FIG. 13 is a view showing a suspended state of a support column.

FIG. 14 is a view showing a suspended state of the connection piece.

FIG. 15 is a sectional view of FIG.

FIG. 16 is a view showing an assembled state of a support column and a traveling rail.

FIG. 17 is a view showing a mounting state of jigs and tools.

FIG. 18 is a view showing an EDM electrode unit.

FIG. 19 is a view showing a mounting state of the EDM electrode unit.

FIG. 20 is a view showing a grinder unit.

FIG. 21 is a view showing a shot blast surface modification unit.

FIG. 22 is a sectional view of FIG. 21.

FIG. 23 is a view showing a laser surface modification unit.

FIG. 24 is a view showing a TIG melting surface modification unit.

25A is a diagram showing an example of repairing a short defect, FIG.
FIG. 6 is a diagram showing an example of repairing a long defect.

FIG. 26 is a diagram showing FIG. 25 in detail.

FIG. 27 is a cross-sectional view showing a state after tightening of FIG. 26.

[Explanation of symbols]

 1 Reactor Vessel (Reactor Pressure Vessel) 1a Control Rod Drive Mechanism Housing 2 Core Shroud 3 Upper Lattice Plate 3a Opening of Upper Lattice Plate 4 Core Support Plate 4a Core Support Plate Opening 5 Crane 8 Installation Jig 9 Free-Swimming Type Robot 17 Upper lattice plate lower chamber 33 Pillar 34 Traveling rail

Claims (3)

[Claims] 1. A method of inspecting and repairing the inside of a core shroud of a reactor vessel provided with an upper grid plate and a core support plate in a state where fuel rods and control rods are removed, wherein the upper grid is previously prepared. Inspection tools, repair jigs and their installation jigs or their assembly parts that are sized so that they can be inserted into the openings of the plate or core support plate,
First, the installation jig or its assembly parts are suspended from above the reactor vessel by a crane in the core shroud, and these are assembled in the core shroud to install the installation jig, and then the installation jig is used for inspection tools and repairs. A process of installing a jig and inspecting and repairing the inside of the core shroud and inserting the installation jig, the inspection tool, the repair jig or the assembly parts thereof into the opening of the upper lattice plate or the core support plate. Also, in the process of assembling or installing these in the core shroud, using a remote-controlled swimming-type robot having thrust means to assist by pressing, grasping, or other positioning operations, Repair method. 2. A plurality of struts having a lower end removably installed in a control rod drive mechanism housing at a lower portion of the reactor vessel and an upper end erected in an upper lattice plate lower chamber in a core shroud of the reactor vessel. An installation jig composed of a traveling rail assembled to the upper end and configured in a ring shape concentric with the core shroud, an inspection tool and a repair jig detachably supported by the traveling rail of the installation jig, and a nuclear reactor A suspending crane and a robot handling device provided at a position facing the core shroud in the upper part of the container, and the installation jig by the crane, which is pulled out from the robot handling device through a cable and inserted into the core shroud, and is inspected. And a swivel robot having a propulsion means for supporting the positioning of an instrument or a repair tool, and the installation jig, the inspection instrument, and the repair instrument. An in-reactor inspection / repair device characterized in that the repair jigs or their assembling parts are sized so as to be inserted into the openings of the upper lattice plate or the core support plate, respectively. 3. The repair jig is a cleaning jig, a grinding or cutting jig, a hole drilling tool, a surface modifying jig, a welding jig or a hole closing jig. The in-reactor inspection / repair device according to claim 2.