JPH0735892A - Working unit in pressure vessel for nuclear reactor - Google Patents

Abstract

PURPOSE:To facilitate the work by suppressing the problem of radioactive resistance and shortening the working time. CONSTITUTION:The working unit comprises a mechanism 19 for loading/ unloading the working unit to/from the flange 4 at the lower end of CRD (control rod driving mechanism) housing 2, a supporting section 12 for securing the working unit to the inner face of the CRD housing 2 while centering, a manipulator being driven in an arbitrary direction, an end effector 18 fixed to the end of manipulator in order to effect a designated work, and a controller for controlling the motions thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for inspecting or processing the internal structure of a reactor pressure vessel.

[0002]

2. Description of the Related Art A conventional apparatus for inspecting or processing the internal structure of a reactor pressure vessel is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-125846.
After removing the upper mirror on the upper part of the pressure vessel and opening the upper part as in Japanese Patent Publication, the target control rod drive mechanism (hereinafter CRD) in reactor water is hung from the upper part by a refueling truck or an overhead crane. After fixing to the work place at the top of the housing, the target work was performed by remote operation.

[0003]

However, the above working method has the following problems.

(1) Even if all the fuel is taken out, the upper lattice plate,
Since core internals such as the core support plate have been activated, high radiation resistance is required for each component when passing through this place or installing in the vicinity such as a cable.

(2) When the working device is inserted to the bottom of the furnace, the path length between the operation control device and the operation control device is as long as 40 to 50 m. Along with this, it is necessary to improve the capacity of the cable as a measure for attenuating the voltage of the power supply, signals, etc., which increases the volume and weight of the cable. (3) When inserting the device into the target openings of the upper grid plate and core support plate, the distance between the device and the operating end must be great, and water must be filled when inserting the device. As a result, positioning is difficult and operation requires time. Further, the working device needs to have a waterproof structure.

(4) In the case of welding work, it takes a long time because the apparatus is inserted with water in the furnace, the water is drained after the upper mirror is attached. In addition, the apparatus needs to stand by in the furnace at the time of draining water, and is exposed to radiation during this period.

An object of the present invention is to provide a working device which can easily perform an inspection work or a working work of a structural material of a reactor bottom portion of a reactor pressure vessel.

[0008]

[MEANS FOR SOLVING THE PROBLEMS] A working device is inserted into the CRD housing from the lower end of the CRD housing in the lower part of the reactor pressure vessel and fixed to a flange at the lower end of the CRD housing. The upper part of the working device is fixed by using the inner surface of the housing or the upper end of the housing, and the manipulator at the tip of the working device is fed into the furnace through the opening at the upper end of the housing to perform the desired work.

[0009]

Since it does not pass through the core portion having a high radiation dose rate, it is possible to apply even the component parts having low radiation resistance to the working device. Also, by using the CRD housing near the work site,
Since the working device is inserted from the lower end of the RD housing to the inner surface of the pressure vessel, the access distance is shortened. The working device is C
Since it is guided by the inner surface and the upper end of the RD housing, the positioning becomes easy and the positioning accuracy is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a CRD housing 2 is welded to a stub 3 welded to the inner surface of a lower mirror portion 1 of a pressure vessel. After removing the control rod and the control rod guide tube, draining the reactor water, the working device 10 in a straight state is inserted into the CRD housing 2, and the working device 10 is equipped with the flange 4 at the lower end of the CRD housing 2. It is fixed by the attaching / detaching mechanism 19. An end effector 8 (a camera with a light in this case) is attached to the tip of the work device 10, and the length and angle of the telescopic arms 16 and 14 and the pitches 17, 15 and 13 are changed to inspect the target welded portion 5. . The arm 11 is rotatably fixed to the inner surface of the CRD housing by a support portion 12. This support portion 12 is stored in the arm 11 when it is inserted, and only when fixed, the three support portions 12 arranged at three places on the circumference are pushed out to push the CRD.
It can be attached to the inner surface of the housing 2 in an aligned manner.
In this example, the centering is performed at one location, but since the length of the CRD housing is about 4 m, it is better to support the CRD housing 2 at two locations above and below the inner surface in the length direction. The turning operation of the arm 11 is driven by rotating the gear 8A by the motor 8 in the working device 10. The telescopic arms 16 and 14, and the pitches 17, 15 and 13 are also driven by actuators such as motors incorporated in the respective arms 11, 14 and 16. In these 6-axis drive control, the lengths and angles are detected by the encoders incorporated therein, and this information is transmitted to a control device (not shown) installed at a remote position via the cable 9,
The controller drives the actuator so that it is compared and calculated with the target value to reach the target value. As a result, the target state is controlled. In addition to the working device for inspection, a working device having an end effector for machining can be attached instead.

The details of the mechanism inside the pitches 17, 15, and 13 are shown in FIG. FIG. 2 shows the pitch 13, and the other pitches 17 and 15 have the same mechanism. Arm 1
4 is rotatably connected to the arm 11 via bearings 62 and 63. There is a stator 52 and a rotor 51 of a ring motor fixed to a holder 53 integrated with the arm 14, and the shaft 50 is fixed to the rotor 51. Therefore, the rotation of the rotor 51 also rotates the shaft 50. In addition, the shaft 50 has a harmonic speed reducer 6
4 and the brake 56 are connected. One spline 54 of the harmonic reducer 64 is fixed to the holder 53, and the other spline 55 is fixed to a holder 67 integrated with the arm 11. Therefore, the shaft 50
The angle between the arm 11 and the arm 14 is changed by the rotation of.
This angle is measured by an encoder 60 connected to the shaft 50 via a gear 61, and a cable (not shown)
To the control device (not shown). A disc 57 is attached to the shaft 50, and the brake 56
Is operated by remote control, the braking plate 58 comes into contact with the disk 57 and brakes the rotation of the shaft 50. Further, the shaft 50 is provided with a lever (not shown) for limiting the operation angle of the arm 14, and the limit switch 59 is operated by this lever. Cables such as actuators, sensors, etc., and tubes located ahead of the arm 14 are guided to the inside of the arm 11 through the opening 66 of the holder 53 and another opening 65.
Pass through 11

The detailed mechanism of the telescopic arms 14 and 16 is shown in FIG. FIG. 3 shows the telescopic arm 14, and the telescopic arm 16 has the same structure. The motor 72 rotates the screw 72 to slide the arm 14A along the inner surface of the arm 14, and the telescopic arm 14A joined to the screw 72 is extended, or the rotation direction of the motor 70 is reversed to be contracted. As for this movement amount, a signal obtained by counting the number of rotations of the screw 72 by the encoder 71 is transmitted to a control device (not shown) via the cable 75. The motor 70 is also driven by a control device (not shown) via a cable 74. The guide bar 73 is used as a detent for sliding the telescopic arm 14A and a wire for the cable 75 and the like.

The detailed mechanism of the support portion 12 is shown in FIG. An opening 85 is provided in the middle of the arm 11, and the opening 85
The roller 82 attached to the supporting bar 84 is taken in and out. When the roller 82 is pressed against the CRD housing 2 to support the arm 11, the shaft 81 is pulled by the air cylinder 80 to raise the angle of the parallelogram link so that the rotatable roller 82 is attached to the inner surface of the CRD housing 2. Push out the bar 84. In this case, since they are evenly arranged at three places (or four places are possible) on the circumference, they can be aligned and supported on the inner surface of the housing. On the contrary, when the arm 11 is inserted into or taken out from the CRD housing 2, the shaft 81B is pushed out by the air cylinder 80 to make the angle of the parallelogram link gentle so that the roller 82B integrated with the bar 84B is moved to the CRD housing 2. Can be separated from the inner surface. The air cylinder 80 operates by remotely turning on the air pressure through the tube 83 and turning off the air.

An example applied to inspection of the welded portion 7 of the shroud support leg 6 will be described with reference to FIG. The working device 20 in this case is attached to the CRD housing 2 near the inspection target, and the attachment / detachment mechanism 19 attaches the CRD housing 2 to the inspection device.
It is attached to the flange 4 at the lower end. This working device 20
Is a two-axis roll 22, 27 in front of the manipulator 21.
And a driving shaft having four axes of pitches 24, 25, 26, and 28, and operating a camera 29 with a light at the tip to inspect the condition of the weld 7. In this case as well, it is fixed in the aligned state by the aligning mechanism (supporting portion) 39 that can be freely taken in and out of the arm 21. These movements are controlled by a control device (not shown) via the cable 9.

The detailed mechanism of the rolls 22 and 27 will be described with reference to FIG. Although FIG. 6 shows an example applied to the roll 22, the roll 27 has the same structure. The arm 23 is rotatably connected to the arm 21 via bearings 98 and 98B. The stator 87 of the ring motor is the arm 21.
It is fixed to a holder 99 which is integrated with. Further, since the shaft 88 is fixed to the rotor 86 of the motor, it is rotated by driving the motor. A harmonic type speed reducer 89 is attached to the shaft 88, one spline 91 is fixed to the holder 99, and the other spline 90 is fixed to the arm 23.
Rotation is reduced to rotate the arm 23. A brake 92 is also attached to the shaft 88, so that the brake 9
When 2 is operated, the braking plate 94 is pressed against the disc 93 integrated with the shaft 88 to brake the rotation of the shaft 88. The rotation angle of the roll 22 axis is measured by an encoder 97 connected via a gear 95. A lever (not shown) is attached to the shaft 88,
By operating the limit switch 96, the range in which the roll 22 rotates is regulated. Further, the shaft 88 is provided with a through hole 100, through which cables such as actuators, sensors, etc., and tubes ahead of the roll 22 are passed. Further, the centering mechanism (supporting portion) 39 of FIG. 5 does not need to be rotatably supported because the roll 22 can rotate the arm 23 and the like further than that, unlike the supporting portion 12 of FIG. That is, when the shaft 81B is extended, the bar 84B is separated from the inner surface of the CRD housing 2 as shown in FIG. Can be inserted or removed. When the arm 21 is aligned and fixed to the housing 2 at a predetermined position, the air cylinder 80 is pneumatically operated to shrink the shaft 81, and the parallelogram links press the bars 84 at the three circumferences to the inner surface of the housing 2. It can be fixed to the housing.

Next, using two CRD housings,
FIG. 8 shows an example of mounting a work device on a table and performing cooperative work. On the flange 4 at the lower end of one of the CRD housings 2, the same 6-axis working device 30 as in FIG. 5 having a welding torch 32 at the tip of the manipulator 31 is attached.
The flange 4B of the other CRD housing 2B has a camera 33 with a light at the tip of the manipulator 31B.
A work device 30B for the shaft is attached. Both manipulators 31 and 31B have an aligning mechanism (support portion) 39,
It is fixed to the inner surface of the CRD housing by 39B. Thereby, the welding state of the work device 30 is monitored by the camera 33 with the light of the other work device 30B. Further, the trajectory of the welding torch 32 is traced in advance by the camera 33 to obtain position information, and the welding torch is guided based on this position information. You can do collaborative work such as. Also in this case, both working devices are cooperatively controlled by the control device (not shown) via the cables 9A and 9B.

The size of the upper opening of the CRD housing is
Since the diameter is 100 mm or less, the outer diameter of the arm of the working device is limited. For this reason, the arm of the working device needs to be downsized, and the rigidity needs to be ensured in order to perform the intended work. However, the rigidity decreases as the number of drive shafts increases or the length of the arm increases. Therefore, as shown in FIG. 9, an auxiliary arm 42 for gripping the shroud support leg 6 is provided at an intermediate portion of the arm 41 of the working device 40.
During the work, the support mechanism 6 is gripped by the gripping mechanism 44 to increase the substantial rigidity. The position of the arm 41 to which the auxiliary arm 42 is attached becomes a problem due to the balance between the degree of freedom of movement of the end effector and the rigidity, but if a dedicated device that limits the application site is used, the gripping mechanism 42 can be simplified. Therefore, the degree of freedom of the tip can be increased.

The details of the gripping mechanism 44 are shown in FIG. 1 attached symmetrically to the tip of the auxiliary arm 42
Set of claws 118, parallelogram ring 113, hinge 114
And the link 115 having the long hole 116, when the shaft 111 is pulled down by the air cylinder 110, the connecting portion 1
12 is lowered to the position of the connecting portion 112B to form the angle of the parallelogram link 113B. Along with this, the claw 118B
Since it also operates in the closing direction, it is possible to grip an object. That is, the air cylinder 110 allows the shaft 1
By performing a linear reciprocating motion of 11, it is possible to grasp and release it.

The end effector at the tip of the arm has a monitoring camera, a welding torch, a working end for inspection of ultrasonic waves, liquid penetration, eddy current, etc., and a working end for machining such as polishing, grinding, cutting, electric discharge and fusing. Yes, these are exchanged according to the purpose.

According to this embodiment, there are the following effects.

(1) Since it does not pass through the core portion in the high radiation region, the component parts used in the working device can have low radiation resistance.

(2) The length of the cable between the working device and the control device can be greatly shortened. As a result, signal attenuation is reduced and the cable can be made thinner, resulting in smaller size and lighter weight. (3) Since the working device can be installed even when there is no reactor water, the work of draining and filling the reactor water can be minimized, and the working time can be greatly reduced. Further, it is not necessary to take waterproofing measures for the working device, the mechanism can be simplified, and the reliability against failure is improved.

(4) Since the flange at the lower end of the CRD housing is used, it is possible to easily replace the working device according to the work.

(5) By attaching two or more working devices to the adjacent CRD housings, complex and complicated work can be performed.

(6) Since the working device can be fixed in the aligned state by utilizing the inner surface or the upper end portion of the CRD housing, the distance to the working end becomes short and the positioning accuracy is improved.

(7) By providing the gripping mechanism in the middle part of the manipulator, the substantial rigidity is improved. The manipulator can be made thinner accordingly, which leads to downsizing.

(8) Since the cables and tubes are all routed through the arm or the drive mechanism section, they do not interfere with the surrounding structures or other working arms when the device is attached or detached and when working, so that workability is improved. improves.

[0028]

According to the present invention, the inspection work or the processing work of the structural material of the reactor bottom of the reactor pressure vessel can be easily performed.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view in which a working device is attached to a CRD housing on the bottom of a furnace.

FIG. 2 is a sectional view of a pitch axis.

FIG. 3 is a sectional view of a telescopic arm.

FIG. 4 is a partial cross-sectional view of a support portion.

FIG. 5 is a partial cross-sectional view showing another working device attached to the CRD housing.

FIG. 6 is a sectional view of a roll shaft.

FIG. 7 is a partial cross-sectional view of another support portion.

FIG. 8 is a partial cross-sectional view in which two working devices are attached to two CRD housings.

FIG. 9 is a partial cross-sectional view in which a working device having a grip portion of a manipulator is attached to a CRD housing.

FIG. 10 is a partial sectional view of a gripping mechanism.

[Explanation of Codes] 1 ... Pressure vessel lower mirror, 2 ... CRD housing, 3 ... Stub, 4 ... Flange, 6 ... Shroud support leg, 9 ...
Cable, 10 ... Working device, 11 ... Arm, 12 ... Support part, 13, 15, 17 ... Pitch, 14 ... Telescopic arm, 1
8 ... end effector, 19 ... detachment mechanism.

Front Page Continuation (72) Inventor Koichi Kurosawa 3-1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd. Hitachi Factory (72) Inventor Nobuyoshi Iwatsuka 7-2-1, Mikamachi, Hitachi City, Ibaraki Prefecture Energy Company, Hitachi, Ltd.

Claims (3)

[Claims] 1. A working device for inspecting and processing an internal structure of a reactor pressure vessel, wherein a working device is inserted from a CRD housing and mounted on a lower end flange, and the CRD.
A supporting portion for aligning and supporting the inner surface of the housing, and the CR
D Manipulator of the working device fed out from the housing into the container, end effector attached to the manipulator for performing a desired work in the container, and a plurality of sensors and actuators incorporated in the working device or the manipulator And a working unit in a reactor pressure vessel, which comprises a control unit that remotely controls a plurality of actuators based on information from a plurality of sensors such as angles and positions. 2. The plurality of adjacent Cs according to claim 1.
A working device in a reactor pressure vessel that allows the plurality of working devices attached to an RD housing to work in cooperation with each other. 3. The working device in a reactor pressure vessel according to claim 1, further comprising means for fixing a part of the manipulator fed into the furnace from the CRD housing to a structure in the furnace.