JPH08201573A - Working equipment in the reactor - Google Patents

Abstract

(57) [Summary] [Construction] The working device includes a peripheral drive unit 21 mounted on the upper part of a shroud in a nuclear reactor and traveling in the peripheral direction, and a vertical drive unit for vertically driving a bending part 35 and a multistage expansion / contraction part 45. Drive unit 22
And a multi-stage expansion / contraction part 45 for moving the working end in the vertical direction, and a bent part 35 for bringing the multi-stage expansion / contraction part 45 closer to the outer surface of the shroud intermediate body 6. [Effect] The work device is miniaturized to improve workability and expand the work range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for working from the outer surface of an existing nuclear reactor shroud, and in particular, performs inspection and repair work while avoiding interference with feed water sparger, core spray piping, jet pump and the like. Regarding the device.

[0002]

2. Description of the Related Art A conventional working device in a furnace is disclosed in JP-A-61-1308.
As described in Japanese Patent Publication No. 67, a moving carriage that moves in the circumferential and radial directions inside the reactor pressure vessel is provided on the upper portion of the reactor pressure vessel, and a mast that vertically expands and contracts is suspended on the moving carriage. An ultrasonic probe is attached to the lower end of the mast, and the ultrasonic probe is scanned along the outer surface of the shroud to inspect the welded portion of the shroud. Further, a conventional in-core inspection device for inspecting the shroud from the inner surface thereof, as described in JP-A-3-261897, fixes the device main body in the furnace by utilizing an upper lattice plate, a core support plate, etc. In addition, a multi-axis arm that can be stored in the main body of the device is provided, and an ultrasonic probe is attached to the end of the arm.The ultrasonic probe is scanned along the inner surface of the shroud and the shroud is inspected. It is supposed to do.

[0003]

However, in the above-mentioned prior art, since the inspection device from the outside is configured to expand and contract in the vertical direction, the inside of the reactor pressure vessel is scanned when the ultrasonic probe is scanned. The mast inside the reactor, such as the water supply sparger, core spray piping, lugs for shroud head bolts, and jet pump, interfered with each other, and the ultrasonic probe was installed in the narrow space between the shroud and the jet pump. It is difficult to approach.

Further, since the movable carriage for suspending the mast is provided above the reactor pressure vessel,
When inspecting the deep inside of the furnace, the mast becomes long and the rigidity is insufficient, so it is difficult to inspect with high positional accuracy.

Further, the inspection from the inside is performed by the upper lattice plate,
Since the apparatus main body is configured to be fixed in the reactor by using the core support plate and the like, large-scale work such as removing the fuel rod is required for inspection. In addition, since the upper lattice plate and core support plate are installed inside, there are some parts that cannot be inspected.

The object of the present invention is to facilitate the installation and removal of the shroud to the reactor shroud and to improve the working efficiency, and at the same time, to apply the shroud to the narrow space to expand the working range. It is to provide working equipment in a nuclear reactor that can be inspected and repaired.

[0007]

In order to achieve the above-mentioned object, the apparatus of the present invention has: 1) means for suspending the apparatus from the upper part of the pressure vessel into the furnace by a wire or the like; 2) length of the apparatus for core spray piping. And a shroud upper flange, a multi-stage expansion / contraction means for making the distance shorter than the shroud upper flange, 3) a means for bringing the suspended device closer to the inner surface of the pressure vessel, and 4) inserting a multi-stage expansion / contraction section between the pressure vessel inner surface and the shroud upper body. , Means for mounting a circumferential drive unit integrated with the shroud upper flange, 5) means for traveling in the furnace in the circumferential direction by the circumferential drive unit mounted on the upper flange, 6) the multistage expansion / contraction unit in the furnace A part of the multi-stage expansion / contraction part is bent while being extended in the axial direction, and the multi-stage expansion / contraction part below the multi-stage expansion / contraction part is brought closer to the outer surface of the shroud; Child, a television camera, the axial direction of the shroud a unit of work such as the discharge electrodes, operated in the circumferential direction,
Means for carrying out inspection and repair work for the purpose.

[0008]

[Operation] By making the length of the inspection / repair device shorter than the distance between the core spray pipe and the shroud upper flange,
The multi-stage expansion / contraction part can be inserted between the inner surface of the pressure vessel and the shroud upper body without interfering with the core spray pipe, and the circumferential drive part integrated with this can be attached to the shroud upper flange. Further, by mounting the circumferential drive portion on the shroud upper flange, it is possible to travel in the circumferential direction along the shroud upper flange. Also, by extending the multi-stage expansion / contraction part and bending a part of the multi-stage expansion / contraction part toward the shroud intermediate body side at the position below the shroud intermediate flange, the multi-stage expansion / contraction part below this can be approached along the outside of the shroud intermediate body. . Further, by extending the multi-stage expansion / contraction part that has been brought close to it, a working unit such as an ultrasonic probe is moved up and down along the outer surface of the shroud, and the circumferential drive section drives the entire device in the circumferential direction. You can perform inspection and repair work.

[0009]

EXAMPLE A side sectional view of a reactor pressure vessel is shown in FIG. The outline of this structure is as follows. Inside the pressure vessel 1 is a partition called a shroud 6 for circulating cooling water, and inside this is a core support plate 5 and an upper lattice plate 4 for supporting fuel rods (not shown). Further, the recirculated water is sent to the bottom of the furnace by the jet pump 10 and then rises in the furnace to exchange heat with the fuel rods. A part of the cooling water is once guided to the outside from the recirculation outlet nozzle 12 and then circulated in the furnace again by the jet pump 10 from the recirculation inlet nozzle (not shown).

The structure of the shroud which isolates these cooling waters in the furnace from the top is such that the upper flange 9, the upper body 8,
It comprises an intermediate flange 7, an intermediate body 6, a lower flange 13 and a lower body 14. Of these, the outer surface of the intermediate cylinder 6, which has a relatively large area, is difficult for the working device to approach because of the following points.
1) At the upper part of the space between the inner surface of the pressure vessel 1, the upper flange 9 and the upper shell 8, a water supply sparger 2, a core spray pipe 3
Since it is laid, it is not possible to approach it straight from the top. 2) Inner surface of pressure vessel 1 and upper flange 9,
The distance between the upper torso 8 is narrow. 3) Since the surface of the intermediate flange 6 is on the inner side compared to the surfaces of the upper flange 9, the upper case 8 and the intermediate flange 7, a step is formed. 4) Since a plurality of jet pumps 10 are arranged in the circumferential direction, it is necessary to avoid this in the circumferential direction. 5) The distance between the shroud intermediate cylinder 6 and the jet pump 10 is very small. 6) The vertical gap between the intermediate flange 7 and the tip of the jet pump 10 is narrow. Therefore, the working device must be able to meet these restrictions.

In the present embodiment shown in FIG. 1, a working device 20 for performing inspection work using ultrasonic waves is provided in each part 9 of the shroud.
The state where the shroud intermediate body 6 is inspected is shown. Working device 20
Is mounted on the upper flange 9 and runs along the peripheral drive unit 21, the multi-stage expansion / contraction unit 45, the bending unit 35, and the connecting unit 2.
4, a vertical drive unit 22 for driving the slider 23 in the vertical direction.
Composed of and. The multi-stage expansion / contraction part 45 and the bent part 35 are housed in the vertical drive part 22 at the time of insertion, and the length of the working device 20 in the vertical direction including the peripheral drive part 21 is set to the core spray pipe 3.
The distance is less than the distance between the lower end of the shroud and the upper end of the shroud upper flange 9, so that the shroud upper flange 9 can be easily inserted from this distance.
The positions of the bending portion 35 and the multi-stage expansion / contraction portion 45 in the circumferential direction at which the plurality of jet pumps 10 are arranged are circumferentially downward.
Is arranged, so that the space between the jet pumps 10 is utilized so as not to interfere with the working device 20.

FIG. 3 shows the state of the working device 20 at the time of insertion. The working device 20 is hung from the upper part of the pressure vessel with a wire or the like, and is vertically drawn between the core spray pipe 3 and the shroud upper flange 9 of FIG. 1 is lowered between the inner surface of the shroud and the upper shroud body 8, and the peripheral drive unit 21 of FIG. 3 is mounted on the upper flange 9 and mounted. The connecting portion 24 connected to the slider 23 and the bending portion 35 of the vertical drive portion 22 can be moved in the vertical direction by rotating the ball screw 26 by the motor 25. As a result, the bent portion 35 and the multi-stage telescopic portion 45 connected to the connecting portion 24 can also move in the vertical direction. That is, the slider 23 is loaded in a state in which it is moved to the upper portion, mounted at a predetermined position, and then moved to the lower portion, and the bent portion 35 is operated under the intermediate flange 7 to move the multi-stage telescopic portion 45 to the shroud as shown in FIG. If you move it to the intermediate body 6,
The multi-stage telescopic part 45 can pass through the narrow part with the jet pump 10. On the other hand, as shown in FIG. 3, the peripheral drive unit 21 mounts the wheel 28 with the collar on the upper flange 9 and presses the opposed hugging wheel 27 against the inner side surface of the upper flange 9 with the air cylinder 29, so that the two wheels. Attach it so that it is sandwiched between 28 and 27. Next, the flanged wheel 28 can be moved on the upper flange 9 in the circumferential direction by driving the wheel 28 with a motor (not shown).

Next, details of the bent portion 35 will be described with reference to FIG. The slider 23 is driven to the vicinity of the lower end by the vertical drive unit 22 attached along the side surface of the shroud upper body 8, and the bent portion 35 connected to this is positioned at the lower portion of the shroud intermediate flange 7. The bent portion 35 includes two sets of air cylinders 26 mounted in parallel with the slider 23.
And a pair of links 32, 31, 30 and a connecting portion 24 connecting these, and the holder 4 is attached to the lower end of the link.
The multistage expansion / contraction part 45 is connected via 4. When the air cylinder 26 is driven by the up-and-down drive unit 22, the shaft 33 of the air cylinder 26 is kept in a contracted state.
5 is substantially below the air cylinder 26 as shown by the chain double-dashed line. When the shaft 33 of the air cylinder 26 is extended after the bent portion 35 is positioned at the lower portion of the shroud intermediate flange 7, the links 32 and 31 open, as shown by the solid line, and the link 30 and the multi-stage expansion / contraction portion 45 are intermediately shrouded. Body 6
Can be placed near.

On the contrary, when the working device 20 is to be recovered, the shafts 33 of the air cylinders 26 can be contracted so that the links 31 and 3 are connected.
2 is closed, and the multistage expansion / contraction unit 45 moves below the vertical drive unit 22. After that, the slider 23 is moved by the vertical drive unit 22.
By moving the upper part, the bending part 35 and the multi-stage expansion / contraction part 45 can be stored in the vertical drive part 22.

Next, details of the multistage expansion / contraction portion 45 will be described with reference to FIG. The multistage expansion / contraction part 45 supported via the link 30 of the bent part and the holder 44 comprises a first arm 40 and a second arm 50. In this example, one motor 60 drives two sliders 41 and 53 at the same time. To do. That is, when the motor 60 is driven, its rotation is transmitted via the gear 61 to the screw 42.
Since the nut 46 integrated with is rotated, the nut 46 moves on the screw 42 which meshes with the nut 46 and moves the slider 41. On the other hand, since the same rotation of the motor 60 is transmitted to the nut 47 on the opposite side via the gears 62, 63, the shaft 64, and the gears 68, 69, 43, the slider 41 can move in the vertical direction by driving from both sides. .

The rotation of the motor 60 is performed by the gears 61, 64, 6
Since it is also transmitted to the two screws 51 via 5, 66 and 67, the two nuts 52 meshing with the two screws 51 move and move the slider 53 in the vertical direction. The probe 70 can also move vertically.
In addition to this vertical movement, the entire multi-stage expansion / contraction portion 45 can also be moved in the circumferential direction by driving the circumferential drive portion 21, so that the entire surface of the shroud intermediate barrel 6 can be remotely checked.

The structure of the multi-stage expansion / contraction unit 45 of this embodiment has been described with respect to the method of driving the two sliders 41 and 53 by the one motor 60. However, it is also possible to drive the two sliders 41 and 53 by the two motors respectively arranged. , Two screws 42 for each axis,
The same object can be achieved by using one screw and one or two sliding arms instead of using 51. When passing through the narrow portion of the shroud intermediate cylinder and the jet pump, not only the influence of the thickness of the multi-stage expansion / contraction portion but also the circumferential width of the multi-stage expansion / contraction portion becomes substantially the same as the increase in thickness. Therefore, in this case, it is effective to have a curvature in the width direction of the multistage expansion / contraction portion in accordance with the curvature of the outer surface of the shroud intermediate body. Further, although the number of expansion and contraction steps has been described as two, the number of expansion and contraction steps is not limited to this, and the number of steps can be increased according to the purpose. Further, the drive mechanism of the combination of the screw and the nut has been described, but for example, it is also possible to perform the expansion and contraction operation by a combination of a method in which the arm is extended by a multistage air cylinder and the motor controls the air pressure to wind up and contract the top wire of the arm. It is possible.

Although the inspection of the shroud intermediate cylinder has been described, the invention is not limited to this, and it goes without saying that the upper cylinder, the lower cylinder, or the welded portions between these and each flange can be inspected. In the case of the lower body, since there is a step between the lower flange and the lower flange, a new second bending part is provided in the multi-stage expansion / contraction part, the second multi-stage expansion / contraction part is bent, and this is brought close to the lower body to perform the desired work. You can also do

In addition to the ultrasonic inspection, the working device in the reactor can be visually inspected by a TV camera by changing the ultrasonic probe of the working unit, and other work such as repair by underwater discharge can be performed. It is also possible to

According to this embodiment, the following effects are obtained.

1) By using a multi-stage telescopic arm,
The vertical length of the working device can be shortened. For this reason, the space between the core spray pipe and the shroud upper flange can be utilized, and it becomes possible to hang it vertically between the inner wall surface of the pressure vessel and the shroud upper shell. This allows the working device to be easily attached to the shroud upper flange. In this way, loading and unloading work becomes easy. Accordingly, the working time can be shortened.

2) By lowering the bending part and the multi-stage expansion / contraction part by the vertical drive part and bending them at a predetermined position, the multi-stage expansion / contraction part can be brought close to the outer surface of the shroud intermediate body even if there is a step in the shroud.

3) In addition to extending or contracting the expansion / contraction part along the outer surface of the shroud intermediate body, the peripheral drive part avoids obstacles such as jet pumps, and ultrasonic waves are generated in the vertical and circumferential directions of the shroud. The probe can be scanned and the entire surface of the shroud intermediate cylinder can be inspected.

4) The thickness of the mechanism can be reduced by arranging the multistage expansion / contraction part in the circumferential direction of the shroud intermediate cylinder. Also, by making the array the curvature of the same concentric circle as the intermediate barrel,
The thickness of the mechanism can be relatively reduced. Therefore, the ultrasonic probe can be scanned while avoiding interference with the jet pump or the like.

[0025]

According to the present invention, since the working device can be downsized, the work efficiency of loading and unloading can be improved and the narrow portion can be traveled, so that the working range can be expanded.

[Brief description of drawings]

FIG. 1 is a perspective view in which a working device of the present invention is attached to a shroud in a nuclear reactor.

FIG. 2 is a partial cross-sectional view showing a main structure inside a nuclear reactor.

FIG. 3 is a perspective view showing a state in which a free running value is attached to the upper part of the shroud.

FIG. 4 is a side view showing an operating state of the bending portion mechanism of the working apparatus of the present invention.

FIG. 5 is a side view showing a configuration of an expansion / contraction mechanism section according to an embodiment of the present invention.

[Explanation of symbols]

6 ... Shroud intermediate cylinder, 8 ... Shroud upper cylinder, 9 ... Shroud upper flange, 20 ... Working device, 21 ... Circumferential drive part, 22 ... Vertical drive part, 23 ... Slider, 24 ... Coupling part, 35 ... Bend part, 45 … Multi-stage expansion and contraction section.

Claims (5)

[Claims] 1. An apparatus for inspecting and repairing internal structural materials by being lowered from the upper part of a pressure vessel of a nuclear reactor, and mounted on a top flange of a shroud to drive in a circumferential direction of the top flange. A vertical drive unit installed between the outer surface of the upper body of the shroud and the inner surface of the pressure vessel, a bent portion housed in the vertical drive unit, connected to the bent portion, and by the bent portion. A working device in a nuclear reactor, comprising: a multistage expansion / contraction part that is brought closer to the outer surface of the middle shell of the shroud; and a work unit housed in the multistage expansion / contraction part for inspecting and repairing the shroud. 2. The working device in a nuclear reactor according to claim 1, wherein the bending portion and the multistage expansion / contraction portion can be moved up and down by the vertical drive portion. 3. The working device in a nuclear reactor according to claim 1, wherein the multistage expandable portion is arranged so as to be stacked in a circumferential direction of the shroud. 4. The working device in a nuclear reactor according to claim 1, wherein the multistage expandable portion is arranged so as to have a curvature of a concentric circle with an outer surface of the shroud. 5. An apparatus for inspecting and repairing internal structural materials when it is lowered from the upper portion of a reactor pressure vessel and mounted on a shroud upper flange so as to run in the circumferential direction of the flange; and A vertical drive part installed between the outer surface of the upper body of the shroud and the inner surface of the pressure vessel, a first bent part housed in the vertical drive part, and a first bent part connected to the first bent part. The first multi-stage expansion / contraction part that is brought closer to the outer surface of the intermediate body of the shroud by the bending part, the second bending part accommodated in the first multi-stage expansion / contraction part, and the second bending part of the shroud. Work in a nuclear reactor characterized by comprising a second multi-stage expansion / contraction part that is brought close to the outer surface of the lower shell, and a work unit housed in the second multi-stage expansion / contraction part for inspecting and repairing the shroud. apparatus.