JPH11166994A - Bolt removal mechanism and bolt removal device - Google Patents

Abstract

(57) [Problem] To provide a bolt detaching device capable of performing high-precision work by remote control without involvement of an operator at the time of mounting and removing a control rod drive mechanism from a reactor. The bolt detachment mechanism includes a flange portion 73 of a control rod drive mechanism for fixing the control rod drive mechanism 5 to a control rod drive mechanism housing 3 provided in a nuclear reactor vessel with bolts 17; And a bolt detaching device 77 disposed opposite to the bolt 73.
Reference numeral 7 denotes a bolt detacher main body 79 which is disposed opposite to the flange portion 73, is detachable in the axial direction with respect to the flange portion 73, and is disposed rotatably. A bolt wrench 19 provided at an opposing portion opposing the flange portion 73 and rotating a bolt; and a laser distance measuring device 99 provided at an opposing portion of the bolt detacher main body.
A detacher main body axial driving device 111 for axially moving the bolt detacher main body toward and away from the flange based on the distance between the bolt detacher main body and the flange measured by the laser range finder 99; doing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt removing device for a control rod driving mechanism which can remotely remove a control rod driving mechanism incorporated in a nuclear power plant.

[0002]

2. Description of the Related Art In a periodic inspection of a boiling water nuclear power plant, as shown in FIG. 8, a control rod driving mechanism provided from a control rod driving mechanism housing 3 provided in a reactor pressure vessel 1 is used. When a CRD 5 (hereinafter abbreviated as CRD) is attached or detached, a CRD exchange 7 that can be remotely operated is employed to reduce the exposure of workers. However, the lower part of the reactor pressure vessel in which the CRD 5 is mounted has a narrow gap and various devices are complicated. Therefore, in order to prevent damage due to contact with each device, at present, workers are involved in some operations. When removing the CRD 5 bolted to the reactor pressure vessel, the CRD 5
Then, the bolt detaching device 9 having the function of loosening the bolt is set. In this case, the bolt detachment device 9 is turned 11 and run 13 by the CRD exchange 7 having a function of supporting and positioning the bolt detachment device 9, and is positioned at a predetermined position. Next, the bolt attaching / detaching device 9 is raised 15 to approach the vicinity of the bolt of the CRD. Then, FIG.
As shown in the figure, the hexagon socket head bolt 17 and the bolt detaching device 9
In order to fit the bolt wrench 19 built in the
The operator needs to be involved, and furthermore, it is necessary to rotate the bolt attaching / detaching device by the rotating motor 21 in accordance with the instruction of the operator to perform centering and fit.

FIG. 10 shows a small wrench 23 for handling the CRD 5 and a large wrench 27 for handling the spool piece 25.
It is a figure which shows the bolt removal machine 29 which has this. Attachment work first attaches the CRD, and then attaches the spool piece. Conversely, removal is the reverse procedure.
FIG. 10A shows a case in which the spool piece 25 is handled, and the large bolt 31 is tightened and loosened as it is with the large wrench 27 attached to the bolt detacher 29. FIG.
(B) shows the case of handling the CRD, in which an attachment 33 is mounted on the bolt detacher 29 to change the wrench size, and the torque of the large wrench 27 is transmitted to the small wrench 23 to tighten and loosen the small bolt 35. Perform As described above, since the work of mounting and detaching the attachment to and from the bolt removing machine is required, it is troublesome, and for this work, most of the entire working time has to be used.

FIG. 11 is a diagram showing a driving method of a bolt wrench. In the bolt attaching / detaching device 37,
The air 39 changes the flow direction by switching the solenoid valve 41 and is supplied to the air motor 43 to change the rotation direction of the air motor 43. The bolt 17 is tightened or loosened. The torque of the air motor 43 is transmitted to the gear train 47 via the torque converter 45,
The torque is controlled by rotating the bolt wrench 19 so that correct tightening and loosening can be performed.

However, in the case of a conventional air motor drive system, it is necessary to switch the pressure control system 49 for pressure control for each required torque, thereby setting the pressure control valve 51. Further, in the case of this system, torque varies depending on the performance of the air motor 43, but since the control system is an open loop,
It was difficult to control this variation.

FIG. 12 shows a drainage system for discharging reactor water. In the bolt detachment device 53, when the bolt loosening is completed and the CRD 5 is removed from the control rod drive mechanism housing 3, the reactor water inside the CRD 5 is removed in order to prevent the activated reactor water 55 from scattering around. Some drainage is required. Conventionally, for this purpose, FIG.
As shown in (1), a seal flange 57 provided at the lower end of the control rod drive mechanism housing 3 is used to seal the space between the flange 57 and the packing 61 of the drain cover 59 to prevent leakage of drain water. However, in this case, it is difficult to adjust the pressing force of the packing 61, and a part of the reactor water easily leaks. In addition, the flange 57 further narrows the narrow gap, resulting in a decrease in workability.

Further, a drain hose 63 is connected to the bolt detaching device 53 so as to prevent the discharged furnace water from scattering around, and the drain water is drained to the drain port 65 through the drain hose 63. However, since the worker connected the drain hose 63, it took time to set and drain the hose, and the workability was poor.

The present invention has been made in view of the above circumstances, and has as its object to provide a high-precision bolt detaching device which is remotely operated without the involvement of a worker when a CRD is attached to or detached from a nuclear reactor. It is in the thing.

[0009]

A first feature of the present invention is as follows.
The control rod drive mechanism includes a flange portion of the control rod drive mechanism for fixing the control rod drive mechanism to a control rod drive mechanism housing provided in the reactor vessel with a bolt, and a bolt detaching device disposed opposite to the flange portion. The bolt detacher is disposed opposite the flange, and is detachably and rotatable in the axial direction with respect to the flange, and is rotatably disposed. A bolt wrench provided on the opposite part of the main body facing the flange to rotate the bolt, a laser range finder provided on the opposite part of the main body of the bolt remover, and a bolt remover main body measured by the laser range finder. A bolt detachment mechanism having a detacher main body axial driving device for axially moving the bolt detacher body toward and away from the flange portion based on a distance between the bolt detacher body and the flange portion.

A second feature of the present invention is that a concave portion for receiving a laser beam from a laser range finder is formed on the front surface of the flange portion facing the bolt detacher main body, and the bolt detacher main body is moved relative to the flange portion. By rotating and detecting the difference between the distance between the laser range finder and the recess and the distance between the laser range finder and the front surface, the position of the bolt detacher body and the flange in the rotational direction is detected, A bolt detachment mechanism further comprising a detacher main body rotation driving device for stopping rotation of the detacher main body when the bolt detacher main body is rotated to a predetermined position with respect to the flange portion.

According to a third feature of the present invention, three laser distance measuring devices and three concave portions are provided on the facing portion of the bolt detacher main body and three front surfaces of the flange portion, respectively. By rotating around the axis and moving in parallel in the radial direction with respect to the axis, and detecting the difference between the distance between the laser range finder and the recess and the distance between the laser range finder and the front surface, the bolt detacher The rotation and radial positions of the main body and the flange portion are detected, and when the bolt detacher body moves to a predetermined position in the rotational direction and the radial direction with respect to the flange portion, the movement of the detacher body is stopped. This is a bolt attaching / detaching mechanism further including an attaching / detaching machine moving drive device.

A fourth feature of the present invention is a bolt detachment device for detaching a bolt for fixing a control rod drive mechanism to a control rod drive mechanism housing provided in a nuclear reactor vessel. A first bolt wrench provided in the bolt detacher body in the axial direction for rotating the bolt, and a second bolt wrench provided in parallel with the first bolt wrench.
The first bolt wrench is provided between the first bolt wrench and the second bolt wrench, and rotates the first bolt wrench in the second bolt wrench while the second bolt wrench is movable in the axial direction.
A bolt wrench rotation transmitting mechanism for transmitting the bolt wrench to the second bolt wrench, and a bolt wrench axial driving device for moving the second bolt wrench in the axial direction.

A fifth feature of the present invention is a bolt detachment device for detaching a bolt for fixing a control rod drive mechanism to a control rod drive mechanism housing provided in a nuclear reactor vessel. A bolt wrench provided on the bolt detacher body for rotating a bolt, a bolt wrench rotation driving device for rotating the bolt wrench, a torque measuring device for measuring a torque applied to the bolt wrench, and the torque measuring device The torque measured in the above, compared with the set torque value, with a rotation torque control device that controls the bolt wrench rotation drive device so that the torque value applied to the bolt wrench becomes the set torque with a bolt removal device is there.

A sixth feature of the present invention is that a control rod drive mechanism housing is provided in a reactor vessel and has an insertion opening formed at a lower end thereof for inserting the control rod drive mechanism, and a control rod drive mechanism formed at a lower end of the control rod drive mechanism. The control rod drive mechanism includes a flange portion fixed to the lower end of the control rod drive mechanism housing by a bolt when the control rod drive mechanism is inserted, and a bolt detachment device disposed opposite to the flange portion. The device is provided on a bolt detacher main body which is disposed opposite to the flange portion and is detachably provided on the flange portion, and is provided on an opposing portion facing the flange portion of the bolt remover main body, and rotates the bolt. A cylindrical cover that is watertight between the bolt wrench to be tightened and the outer periphery of the bolt remover body, and that can fit the outer peripheral surface of the lower end of the housing while accommodating the flange therein, and this cover An annular seal member provided on an inner peripheral portion fitted to the outer periphery of the lower end of the housing, wherein the annular seal member protrudes inward toward the outer peripheral surface of the lower end of the housing at the time of sealing to form a watertight state between the outer peripheral surface of the lower end of the housing. A bolt detachment mechanism having a sealing member that is sealed and separated from the outer peripheral surface of the lower end of the housing when not sealed, and a drain passage that opens to the front surface of the bolt detacher main body and drains reactor water.

A seventh feature of the present invention is that the bolt attaching / detaching device further includes a reactor water tank connected to the drain passage.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. Parts having the same configuration as the conventional example are denoted by the same reference numerals.

FIGS. 1 to 3 are views showing an outline of a bolt attaching / detaching mechanism according to a first embodiment of the present invention. FIG. 1 is a front view thereof, and FIG. 2 is a II-II in FIG. FIG. 3 is an enlarged view of a part III in FIG. 1 along a line.

In FIG. 1, a control rod driving mechanism housing (hereinafter referred to as "CRD housing") 3 has an enlarged diameter portion 71 formed at a lower end thereof. The CRD housing 3 has a control rod driving mechanism (hereinafter referred to as "CRD housing"). CRD "). 5 has been inserted. A flange 73 having substantially the same diameter as the enlarged diameter portion 71 is provided below the CRD 5. Then, the CRD 5 is fixed to the CRD housing 3 by fixing the flange portion 73 to the enlarged diameter portion 71 with the hexagon socket head bolt 17. As shown in FIG. 2, the hexagon socket head cap screw 17 is
4 are arranged on a virtual circumference 75 on the display 4.

Below this flange portion 73, a bolt attaching / detaching device 77 is arranged. This bolt removal device 77
Is a column-shaped bolt detaching device main body 79 coaxial with the CRD 5.
have. A bolt wrench 19 is provided on an opposing surface 81 of the main body 79 that faces the flange 73 of the bolt attaching / detaching device 79. A plurality of the bolt wrenches 19 are arranged on an imaginary cylindrical surface 83 having the same radius as the imaginary circumference 75 of the flange portion 73 around the axis of the bolt attaching / detaching device main body 79, and each is rotated by a driving device (not shown). It has become.

The main body 79 of the bolt attaching / detaching device is mounted on the elevating device 85 so as to be rotatable around its axis. The elevating device 85 is connected to an elevating motor 91 via a connecting belt 87 and a pulley 89.
To move up and down in the axial direction. Further, the main body 79 of the bolt attaching / detaching device is connected to a turning motor 97 via a transmission mechanism 95 such as a peripheral gear 93 wound around the peripheral gear and a gear engaged with the peripheral gear, and the axis thereof is It can rotate around the center.

A laser distance measuring device 99 is provided on the facing surface 81 of the bolt attaching / detaching device main body 79. The laser range finder 99 includes a flange portion 73 facing the virtual cylinder 83.
Is disposed toward the front surface 74 of the camera. On the other hand, a detection recess 101 is formed on the front surface 74 of the flange portion 5.
The detection concave portion 101 has a first concave portion 103 and a second concave portion 105 further formed in the center bottom of the first concave portion. In addition, the detection concave portion 101 has a virtual circumference 7.
5, three are provided.

The laser range finder 99 is connected to a motor controller 111 via a cable 107 and an amplifier 109. The motor control device 111 is connected to the turning motor 97 and also to the lifting motor 91.

In such a configuration, when removing the hexagon socket head bolt of the CRD 5, first, the lifting / lowering motor 91 is driven, and the main body 79 of the bolt attaching / detaching apparatus is brought close to the flange 73. The approach speed at this time is adjusted to three stages of high speed, medium speed, and low speed according to the measurement value of the laser range finder. The laser distance measuring device 99 measures the distance between the front surface 74 of the flange portion 73 and the tip of the bolt wrench 19 and the hexagon socket head bolt 17.
As shown in FIG. 3, the distance between the head and the
Then, the lifting device 85 is stopped.

Next, the turning motor 97 is driven to rotate the main body 79 of the bolt attaching / detaching device. Then, the laser range finder 9
9 rotates and approaches the detection recess 101. As the laser range finder approaches the detection recess 101, the laser range finder 99
The positional relationship between the sensor and the detection recess 101 changes in the order of X, Y, and Z in FIG. When the positional relationship X changes from the positional relationship X to the positional relationship Y, the measurement distance of the laser range finder 99 changes, and this change is detected by the motor control device 111. Then, the motor control device 111 issues a deceleration command to the swing motor 97 to reduce the rotation of the bolt attaching / detaching device main body 79. Then, the positional relationship Y
Is changed to the positional relationship Z, the laser
The motor control device 1 detects the change in the measurement distance of
Numeral 11 stops the rotation of the main body 79 of the bolt attaching / detaching device. In this way, the centering of the bolt wrench 19 and the hexagon socket head bolt 17 in the circumferential direction is performed. Further, although not shown, x which is perpendicular to the axis of the bolt attaching / detaching device main body.
By combining the moving device in the y direction and the three detecting recesses, the axis of the main body of the bolt attaching / detaching device is moved in the xy directions. Let it complete.

Then, the lifting device 85 is driven again, the tip of the bolt wrench 19 is fitted into the hexagonal hole of the hexagonal bolt 17, and after a certain pressing load is applied, it is stopped.

As described above, in this embodiment,
The centering of a bolt wrench and a hexagonal hole bolt, which has conventionally been performed by an operator, can be automatically performed by remote control.

FIG. 4 is a view showing a bolt attaching / detaching apparatus according to a second embodiment of the present invention. In this figure,
The CRD housing 3 includes a flange 73 of the CRD 5.
Are fixed with hexagon socket head bolts 17. At a position facing the flange portion 73, a bolt detaching device 121 is arranged. The bolt attachment / detachment device 121 has a bolt attachment / detachment device main body 79, and a plurality of bolt wrenches 19 are provided on the flange portion 73 side.

Each of the bolt wrenches 19 is connected to a torque converter 125 via a gear train 123 provided at the rear thereof. This torque converter 125
It is connected to the output shaft of the air motor 127.

A supply source 129 of the air supplied to the air motor is connected to a solenoid valve 133 through a pressure regulating valve 131, and the solenoid valve 133 is connected to an air motor 127. On the other hand, the output terminal of the torque converter 125 is
The control device 137 is connected to the control device 137 via the amplifier 135. The control device 137 is connected to the multi-stage pressure regulating valve 139.

In such a configuration, first, an air pressure command corresponding to the specified torque of the bolt wrench 19 is sent from the control device 137 to the multi-stage pressure adjusting valve 139. As a result, the pressure regulating valve 131 operates, and air at a specified pressure is supplied to the solenoid valve 133. Next, switching between tightening and loosening is performed by the solenoid valve 133, and predetermined air is supplied to the air motor 127.
To be supplied. Then, the rotation torque of the air motor 127 is transmitted to the bolt wrench 19 via the torque converter 125 to rotate the hexagon socket bolt 17. On the other hand, at this time, the torque converter 125 measures the torque and sends it to the control device 137 via the amplifier 135. Thereby, it is determined whether the measured torque is higher or lower than the set value, the control is fed back to the multi-stage pressure adjusting valve 139, and the air pressure is automatically controlled.

As described above, in this embodiment, by providing the feedback function, the pressure adjusting system conventionally provided in many places can be made possible by one multi-stage pressure adjusting valve, and the bolt is set at a predetermined set torque. It is possible to securely tighten.

FIG. 5 is a view showing a bolt attaching / detaching apparatus according to a third embodiment of the present invention. In this figure,
The CRD housing 3 includes a flange 73 of the CRD 5.
Are fixed with hexagon socket head bolts 17. At a position facing the flange portion 73, a bolt attaching / detaching device 141 is arranged. The bolt attaching / detaching device 141 has a columnar bolt attaching / detaching device main body 79, and a plurality of large bolt wrenches 143 are provided on the flange portion 73 side.

The large bolt wrench 143 is used to rotate a bolt for fixing the spool piece 145, and a plurality of the large bolt wrench 143 are arranged on an imaginary cylindrical surface 83 centered on the axis of the bolt detacher body 79. . A rear gear 147 is provided at the rear of the large bolt wrench 143, and is driven by a gear connected to an air motor (not shown). In the middle of the large bolt wrench 143, there is provided an axially long central gear 149 for driving a small bolt wrench to be described later.

Near the side of the large bolt wrench 143, a small bolt wrench 151 is provided in parallel with the large bolt wrench. This small bolt wrench 151 is CRD5
And is provided so as to be movable in the axial direction and rotatable. In the middle of the small bolt wrench 151, a sliding gear 153 that engages with the central gear 149 of the large bolt wrench 143 is provided. The sliding gear 153 is a central gear 1 long in the axial direction.
The small bolt wrench 151 can be moved in the axial direction with the movement of the small bolt wrench 151 while maintaining the engagement state with the small bolt wrench 49, and the rotational force of the large bolt wrench 143 is reduced regardless of whether the small bolt wrench 151 is in the projected state or the retracted state. The power can be transmitted to the bolt wrench 151.

A vertical drive cylinder 155 for driving the small bolt wrench 151 in the axial direction is provided at the rear end of the small bolt wrench 151. This vertical drive cylinder 155
Has a spring inside, and when the air is supplied, the small bolt wrench 151 is protruded to the projecting position against the urging force of the spring. On the other hand, when the air is not supplied, the small bolt wrench 151 is pulled in by the urging force of the spring. It is designed to retract into position. An air solenoid valve 157 is connected to the vertical drive cylinder 155,
A pressure regulating valve 159 is connected to the air solenoid valve 157. An air supply source 161 is connected to the pressure adjusting valve 159. Also, the air solenoid valve 15
A pressure gauge 163 is connected between the pressure control valve 7 and the pressure regulating valve 159.

In such a configuration, the hexagon socket head bolt 1 of the flange 73 of the CRD 5 is
In order to fasten and remove 7, first, the air solenoid valve 157 is opened, and the air from the air supply source 161, which is set to a predetermined pressure by the pressure adjusting valve 159, is supplied to the vertical drive cylinder 155. Then, as shown in FIG. 5A, the vertical drive cylinder 155 moves the small bolt wrench 151 upward against the urging force of the built-in spring.
At the same time, the rotation drive source of the bolt wrench (not shown) is operated, and the large bolt wrench 14 is driven via the rear gear 147.
Rotate 3 Then, the torque of the large bolt wrench 143 is transmitted to the small bolt wrench 151 via the central gear 149 and the sliding gear 153. In this manner, the hexagon socket head bolt 17 of the flange 73 is tightened and removed by the small bolt wrench 151.

To tighten or remove the hexagon socket head cap bolt 18 of the spool piece 145 with the large bolt wrench 143, the air solenoid valve 157 is closed and the supply of compressed air to the vertical drive cylinder 155 is stopped. Then, as shown in FIG. 5B, the vertical drive cylinder 155 is
The small bolt wrench 151 is moved downward by the biasing force of the built-in spring, and the large bolt wrench 143 is relatively protruded forward. After that, large bolt wrench 143
Is rotated via the rear gear, and the spool piece 14 is rotated.
Tighten and remove the hexagon socket head bolt 18 of No. 5.

As described above, in this embodiment,
Large bolt wrench and small bolt wrench of different sizes can be handled without using an attachment, and the working time can be greatly reduced.

FIG. 6 is a view showing a bolt attaching / detaching mechanism 171 according to a fourth embodiment of the present invention. In this figure, an enlarged diameter portion 71 is formed at the lower end of the CRD housing 3, and an outer peripheral surface 17 is formed on the outer periphery of the enlarged diameter portion 71.
3 are formed. This CRD housing 3 has C
The RD 5 is inserted, and a flange 73 having substantially the same diameter as the enlarged diameter portion 71 is provided below the CRD 5.
The CRD 5 is fixed to the CRD 5 by fixing the flange portion 73 to the enlarged diameter portion 71 with the hexagon socket head bolt 17.
The RD housing 3 is fixed to the RD housing 3.

Below this flange portion 73, a bolt attaching / detaching device 175 is arranged. This bolt removal device 1
Reference numeral 75 has a column-shaped bolt detaching device main body 79 coaxial with the CRD 5. A bolt wrench 1 is provided on an opposing surface 81 of the main body 79 that faces the flange 73.
9 are provided.

A cylindrical cover 177 is provided on the outer periphery of the column-shaped bolt detaching device main body 79. The cover 177 is vertically slidably fitted to the main body 79 while maintaining a watertight state between the cover 177 and the main body 79. As shown in FIG. 7, an annular annular groove 179 is formed on the inner peripheral surface of the upper end of the cover 177.
One is inset. When compressed air is supplied into the annular groove, the air tube projects radially inward to perform a sealing action. On the other hand, an opening 183 is formed at the bottom of the annular groove 179, and an air supply line 185 is connected to the opening 183. The air supply line 185 includes a coupler 18
7, an air solenoid valve 189 is connected, and a pressure regulating valve 191 is connected to the air solenoid valve 189. An air supply source 193 is connected to the pressure regulating valve 191. Also, the air solenoid valve 189
A pressure gauge 195 is connected between the pressure control valve 191 and the pressure control valve 191.

On the other hand, the facing surface 8 of the bolt attaching / detaching device body 79
1, a drain passage 197 is opened, and the drain passage 197 passes through the inside of the bolt detaching device main body 79, and is connected to a water storage tank 199 provided in the bolt detaching device main body 79. The water storage tank 199 has a drain port 201 which opens to the outside of the main body 79 of the bolt attaching / detaching apparatus, and the drain port 201 is provided with a solenoid valve 203 for drain.

In such a configuration, to remove the CRD 5, first, the bolt attaching / detaching device main body 79 is raised to face the flange portion 73. Next, the cover 177 is raised and the upper end of the cover 177 is fitted to the enlarged diameter portion 71. Thereafter, the air solenoid valve 189 is opened, and the compressed air having a predetermined pressure from the air supply source 193 by the pressure adjustment valve 191 is coupled to the coupler 187 and the air supply line 18.
5 to the annular groove 179. Then, the air tube 181 is pushed inward in the radial direction, pressed against the outer peripheral surface 173 of the enlarged diameter portion 71, and the cover 177 and the enlarged diameter portion 71 are sealed. Thereafter, the bolt wrench 19 is operated to loosen the hexagon socket head cap bolt 17 and take out the CRD 5.
At this time, the reactor water 205 in the CRD housing 3 flows out, but since the cover 177 seals between the bolt detachment device main body 79 and the enlarged diameter portion 71, the reactor water 205 may be scattered. Can be prevented. Further, the reactor water 205 flowing out to the facing surface 83 of the bolt detachment device main body 79.
Flows into the water storage tank 199 through the drain passage 197 and is temporarily stored therein. Then, after that, when the bolt detaching device 171 comes to a predetermined position, the drainage electromagnetic valve 201 is opened, and the furnace water 205 stored in the water storage tank 199 is discharged to the drain port 2.
Drain to 07. Therefore, since the furnace water can be drained at a predetermined position, the surrounding can be prevented from being contaminated.

As described above, in the present embodiment, C
When the RD is removed from the flange of the reactor pressure vessel and descends, it is possible to prevent reactor water from leaking around the flange of the reactor pressure vessel, and according to this method, there is a problem with the conventional sealing performance. The need for a sealed flange is eliminated. Furthermore, the provision of the water storage tank eliminates the need for a conventional drain hose, and eliminates the need for an operator who handles the drain hose, and ensures drainage.

As described above, in the related art, it has been difficult to mount and remove the CRD to and from the reactor pressure vessel in the environment of the radiation control area. However, the centering is performed by the bolt detaching device and the detaching mechanism according to the present invention. It is possible to improve the tightening torque management related to external leakage and to install automatic centering device, torque control device capable of automatic control, and device to prevent reactor water leakage, so that these operations can be performed automatically and remotely. It can be carried out. Therefore, when removing and attaching the CRD from the reactor, the setting of the bolt attaching / detaching machine and the tightening torque can be managed with high accuracy. Furthermore, since the air tube can prevent the reactor water from leaking,
These tasks can be accomplished remotely and automatically without the involvement of workers.

[0046]

As described above, according to the present invention,
When the CRD is detached from the reactor pressure vessel, the work of centering on the CRD, tightening and loosening the bolts, and draining the reactor water can be performed remotely and reliably without the involvement of an operator. Therefore, it is possible to reduce the exposure of the worker, to facilitate the work in the narrow gap, and to improve the working efficiency.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a bolt attaching / detaching mechanism according to a first embodiment of the present invention.

FIG. 2 is an arrow view along the line II-II in FIG.

FIG. 3 is an enlarged view of a portion indicated by reference numeral III in FIG.

FIG. 4 is a diagram schematically showing a bolt attaching / detaching apparatus according to a second embodiment of the present invention.

5A and 5B are diagrams schematically illustrating a bolt attaching / detaching device according to a third embodiment of the present invention, wherein FIG. 5A illustrates a case where a bolt of a control rod driving mechanism is handled, and FIG. The figure which shows the case where the bolt of FIG.

FIG. 6 is a view schematically showing a bolt attaching / detaching mechanism according to a fourth embodiment of the present invention.

FIG. 7 is an enlarged view of a portion indicated by reference numeral VII in FIG.

FIG. 8 is a perspective view showing a CRD replacement operation in a lower part of the reactor pressure vessel.

FIG. 9 is a view schematically showing centering of a conventional bolt removing mechanism.

10A and 10B are diagrams schematically illustrating a case where a bolt of a different size is handled by a conventional bolt detaching mechanism, wherein FIG. 10A is a diagram illustrating a case of handling a large-sized bolt, and FIG. The figure which shows the case where a bolt is handled.

FIG. 11 is a diagram schematically showing a case where a tightening torque is controlled by a conventional bolt attaching / detaching mechanism.

FIG. 12 is a diagram schematically showing a drainage system of a conventional bolt detachment mechanism.

[Explanation of symbols]

 3 Control Rod Drive Mechanism Housing (CRD Housing) 5 Control Rod Drive Mechanism (CRD) 19 Bolt Wrench 73 Flange 77 Bolt Detachment Device 79 Bolt Detachment Device Main Body 91 Elevating Motor 97 Rotating Motor 99 Laser Distance Measuring Device 101 Detection Concave 111 Motor Control Device 125 Torque converter 127 Air motor 137 Control device 143 Large bolt wrench 149 Central gear 151 Small bolt wrench 153 Sliding gear 155 Vertical drive cylinder 177 Cover 181 Air tube 197 Drainage channel 199 Water tank

Claims (7)

[Claims] 1. A control rod drive mechanism for fixing a control rod drive mechanism to a control rod drive mechanism housing provided in a nuclear reactor vessel with a bolt, and a bolt disposed opposite to the flange. A bolt attaching / detaching device, which is provided to face the flange portion, and is detachably attached to and rotatable in the axial direction with respect to the flange portion. A main body, a bolt wrench provided on an opposing portion of the main body of the bolt detacher opposing the flange portion and rotating the bolt, and a laser range finder provided on the opposing portion of the main body of the bolt detacher. A detacher main body shaft for axially moving the bolt detacher main body toward and away from the flange portion based on a distance between the bolt detacher main body and the flange portion measured by a laser distance measuring device. A directional drive device. 2. A concave portion for receiving a laser beam from the laser range finder is formed on a front surface of the flange portion facing the bolt detacher main body, and the bolt detacher main body is rotated with respect to the flange portion. And detecting the difference between the distance between the laser range finder and the concave portion and the distance between the laser range finder and the front surface, so that the position of the bolt detacher main body and the flange portion in the rotational direction is detected. And further comprising a detacher main body rotation drive device for stopping the rotation of the detacher main body when the bolt detacher main body is rotated to a predetermined position with respect to the flange portion. The bolt attaching / detaching mechanism according to claim 1. 3. The laser range finder and the concave portion are provided on the facing portion of the bolt detacher main body and the front surface of the flange portion in three sets, respectively. Detecting the difference between the distance between the laser range finder and the concave portion and the distance between the laser range finder and the front surface by rotating the laser range finder and parallel movement in the radial direction with respect to the axis. By detecting the positions of the bolt detacher body and the flange portion in the rotational direction and the radial direction, when the bolt detacher body moves to predetermined positions in the rotational direction and the radial direction with respect to the flange portion. 2. The bolt detachment mechanism according to claim 1, further comprising a detachment unit movement driving device for stopping the movement of the detachment unit body. 4. A bolt detacher for detaching a bolt for fixing a control rod drive mechanism to a control rod drive mechanism housing provided in a nuclear reactor vessel, comprising: a bolt detacher main body; and a bolt detacher main body. A first bolt wrench that is provided in the axial direction and rotates the bolt; a second bolt wrench disposed in parallel with the first bolt wrench; a first bolt wrench and the second bolt wrench A bolt wrench rotation transmitting mechanism that is provided between the bolt wrench and transmits the rotation of the first bolt wrench to the second bolt wrench in a state where the second bolt wrench is movable in the axial direction; A bolt wrench axial driving device for moving the second bolt wrench in the axial direction. 5. A bolt detachment device for detaching a bolt for fixing a control rod drive mechanism to a control rod drive mechanism housing provided in a nuclear reactor vessel, comprising: a bolt detacher main body; and a bolt detacher main body. A bolt wrench for rotating the bolt, a bolt wrench rotation drive for driving the bolt wrench, a torque measuring device for measuring a torque applied to the bolt wrench, and a torque measured by the torque measuring device. A rotation torque control device that controls a bolt wrench rotation driving device so that a torque value applied to the bolt wrench becomes a set torque by comparing the set torque value with the set torque value. . 6. A control rod drive mechanism housing provided in a reactor vessel and having an insertion opening formed at a lower end thereof for inserting the control rod drive mechanism; and a control rod drive mechanism formed at a lower end of the control rod drive mechanism. A flange portion fixed to the lower end of the control rod drive mechanism housing with a bolt when the mechanism is inserted, and a bolt detachment device disposed opposite to the flange portion, wherein the bolt detachment device comprises: A bolt detacher body that is disposed to face the portion and that is detachably attached to the flange portion; and a bolt remover body that is provided at an opposite portion of the bolt remover body that faces the flange portion and rotates the bolt. A bolt-shaped wrench and an outer periphery of the main body of the bolt detacher are made watertight, and a cylindrical shape capable of fitting to the outer peripheral surface of the lower end of the housing while accommodating the flange portion therein. A bar, and an annular seal member provided on an inner peripheral portion of the cover fitted to the outer periphery of the lower end of the housing, wherein the seal protrudes inward toward the outer peripheral surface of the lower end of the housing at the time of sealing. A sealing member that seals between the outer peripheral surface in a watertight state and is separated from the outer peripheral surface of the lower end portion of the housing when the sealing is not performed; and a drain passage that opens to the front surface of the bolt detacher body and drains the reactor water. And a bolt detachment mechanism characterized by having: 7. The bolt detaching mechanism according to claim 6, wherein the bolt detaching device further includes a reactor water tank connected to the drain passage.