JPH06118196A - Handling device for control rod drive mechanism - Google Patents

Abstract

PURPOSE:To improve the reliability of handling work by detecting the exact position of wrench device, control rod drive mechanism and housing. CONSTITUTION:Around the wrench device 29 for bolt detaching device 30, a rotation drive device rotated by driving is provided. To this rotation drive device, a motor 10, a motor blacket 9, a spool piece 8a and a displacement meter capable of detecting the position of main body of the control rod drive mechanism 2 from the housing are provided. Around the housing 5, a disk 32 is provided as a target.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control rod drive mechanism handling apparatus for attaching and detaching a control rod drive mechanism to and from a reactor pressure vessel in a boiling water reactor.

[0002]

2. Description of the Related Art Generally, in a boiling water reactor, a control rod driving mechanism provided at a lower portion of a reactor pressure vessel inserts / removes control rods into / from the reactor core to control the output of the reactor.

That is, as shown in FIG. 7, a large number of control rod drive mechanisms 2 are provided below the boiling water reactor pressure vessel 1.
The control rod 3 connected to the top of the control rod drive mechanism 2 is inserted into or pulled out from the core 4.

FIG. 8 shows a vertical cross section of the conventional control rod drive mechanism 2. A long housing 5 penetrates and is fixed to the lower end of the reactor pressure vessel 1 which is shown only partially in FIG.

A control rod drive mechanism 2 is fixed to the housing 5 by mounting bolts 6, and an outer tube 7 and a guide tube 8 are concentrically arranged inside the housing 5 and fixed in order.

At the lower end of the outer tube 7, an electric motor is mounted via a spool piece 8a and an electric motor bracket 9.
10 is installed. The electric motor 10 drives the control rod 3 to be inserted and removed, and the rotation of the rotation start shaft 11 is transmitted to the rotation transmission shaft 13 via the gear device 12.

The upper end of the rotation transmitting shaft 13 is connected to the drive screw 14 by a keyed groove. The drive screw 14 is formed to have a length that extends from the lower end to the upper end of the housing 5, and a nut 15 is screwed into the drive screw 14.

The nut 15 is prevented from rotating by engaging a roller 16 attached to the outer periphery of the nut 15 with a groove 17 formed in the inner surface of the guide tube 8, and is raised or lowered by the forward or reverse rotation of the drive screw 14. To be made.

On the nut 15, a long hollow piston 18 which covers the outside of the drive screw 14 is mounted so that it can come into contact with and separate from the nut 15. This hollow piston 18 is the upper coupling spout that connects the control rod when the nut 15 is in its lowest position.
19 is formed in the reactor pressure vessel 1 so as to have a length just protruding.

The hollow piston 18 is prevented from rotating by engaging the roller 16 attached to the lower end with the groove 17.
Further, there is provided a latch 20 which engages with a window (not shown) opened in the guide tube 8 to prevent the hollow piston 18 from falling.

Inside the housing 5, its lower flange,
Water (purge water) is constantly filled through the inlet 21 provided in the order of the outer tube 7 and the guide tube 8. This water is used by the hollow piston 18 and the labyrinth seal 22.
It has flowed into the reactor pressure vessel 1 through a gap between and.

The insertion and withdrawal of ordinary control rods by the control rod drive mechanism 2 thus formed are performed as follows.

That is, by rotating the electric motor 10 forward and backward, the drive screw 14 is rotated forward and backward, and the nut 15 is raised or lowered. Then, the hollow piston 18 placed on the nut 15 by its own weight moves up and down together, and the control rod connected to the upper end of the hollow piston 18 via the coupling spat 19 is inserted into the core 4. Pulled out.

On the other hand, when quick insertion of the control rod is required,
High pressure water is introduced from the inlet 21 into the hollow piston 18 inside the housing 5.
Of the hollow piston 18, which is placed on the nut 15 only by its own weight and separated from the nut 15,
It moves rapidly upward and the control rods are rapidly inserted into the core 4.

Thereafter, the lower end of the latch 20 engages with the underline of the window (not shown) to prevent the hollow piston 18 from descending. When the hollow piston 18 is lowered again by the electric motor 10, the drive screw 14 is rotated in the insertion direction, the nut 15 and the hollow piston 18 are brought into contact with each other, the latch 20 is returned to the inside, and the engagement with the window is released. Then, the drive screw 14 is rotated in the pulling-out direction to lower the hollow piston 18.

At the end of the rapid insertion of the control rod 3, it is necessary to decelerate the heated hollow piston 18 and the control rod 3. For this reason, the control rod drive mechanism 2 is provided with a disc spring 23 as a buffer mechanism above. The heated hollow piston 18 collides with the throttle 24 and the throttle 24 becomes a disc spring.
23 is pressed to reduce the speed.

Thereafter, as described above, the latch 20 of the hollow piston 18 engages with the lower edge of the window (not shown), and
Although the descent of 18 is prevented, it is necessary to monitor that the hollow piston 18 and the control rod 3 are inserted in the core for the operation management of the reactor.

For this reason, as shown in FIG.
A stop piston 25 is provided in the front stage of the above, and when the hollow piston 18 is in the latch position, the stop piston 25 is configured to be lifted a little upward. In addition, the reference numeral in FIG.
26 is a control rod guide tube base, 27 is an outer tube upper guide, and 28 is a coil spring.

The control rod drive mechanism 2 configured as described above is disassembled and assembled in the following manner during the periodic inspection.

First, the electric motor 10 is removed from the electric motor bracket 9, and the spool piece 8a is removed from the electric motor bracket 9.
Remove. Next, the spool piece 8a is removed from the control rod drive mechanism 2.

Finally, as shown in FIGS. 9 and 10, the four rods a provided at the tip of the hollow piston 18 and the bayonet coupling spat 19 of the socket b provided in the control rod 3 are driven by the control rod. The control rod drive mechanism 2 is removed from the inside of the housing 5 by rotating the entire mechanism 2 by 45 ° to bring it into an uncoupled state.

The bayonet coupling spat 19 shown in FIGS. 9 and 10 is constructed as follows.

That is, the four fingers a provided at the tip of the hollow piston 18 are inserted into the socket b provided at the lower portion of the control rod 3 for coupling, that is, coupling. The inner surface of the socket b is provided with four protrusions c at equal intervals, and the protrusion c has the above-mentioned finger a.
A recess e is formed in which the bulging portion d provided on the outer surface is inserted.

When the bulging portion d of the finger a is inserted into the dent e of the protrusion c in the socket b, the bulging portion d is brought into a coupled state, and when the bulging portion d is disengaged from the dent e by turning 45 °, the coupling is released. It becomes the uncoupling state and is removed.

The control rod drive device 2 is detached or attached by a dedicated wrench device 29 and a bolt attaching / detaching device 30 according to the respective constituent parts shown in FIG.

FIG. 11 shows a state in which the bolt attaching / detaching device 30 is arranged between the control rod driving devices 2 and 2. An example of the handling procedure of the bolt attaching / detaching device 30 will be described with reference to FIG.

That is, the wrench device 29 for attaching and detaching the bolt of the spool piece 8a is mounted on the bolt attaching / detaching device 30, and is lifted by an elevator truck (not shown), and then the bolt attaching / detaching device.
The control rod drive mechanism 2 is attached or detached with a bolt by a predetermined operation of 30.

All of these operations are performed by an operator operating a switch or the like on the control panel from a control room by remote driving.

[0029]

When the control rod drive mechanism 2 is regularly inspected, the control rod drive mechanism 2 is moved from the inside of the housing 5.
If the uncoupling is incomplete for some reason when the coupling is moved from the coupling state to the uncoupling state during the work of removing the hollow piston 18, the hollow piston 18 is attached to the control rod 3.

When the control rod drive mechanism 2 is pulled out in this state, the hollow piston 18 and the nut 15 are separated and the control rod drive mechanism 2 is removed.
Cannot be removed from the housing 5. In addition, if the hollow piston 18 attached to the control rod 3 comes off due to some reason and falls, the nut
A large impact load is applied to 15. Therefore, the hollow piston 18
It is necessary to confirm that the control rod 3 is completely uncoupled.

When the conventional control rod drive mechanism 2 is removed, a load meter is attached to the bolt attaching / detaching device 30 and the hollow piston 18 is removed.
Is monitoring the weight of. Further, it is confirmed by attaching marks to the outer peripheral portion of the flange of the housing 5 and the flange portion of the control rod drive mechanism 2 and aligning the marks.

However, in the load cell of the bolt attaching / detaching device 30, since the weight of the hollow piston 18 is small with respect to the entire load, it is difficult to detect the weight of the hollow piston 18. Further, there is a problem that it is impossible to visually check the marks of each flange portion in a forested state of the control rod drive mechanism.

The present invention has been made to solve the above problems, and can easily detect the uncoupling between the piston and the control rod, and can detect and handle the accurate positions of the wrench device and the control rod drive mechanism housing. It is an object of the present invention to provide a handling device for a control rod drive mechanism that improves work reliability.

[0034]

The present invention provides an electric motor, an electric motor bracket, and a spool piece that constitute a control rod drive mechanism that is equipped with a wrench device and a bolt attaching / detaching device and is attached to a housing penetrating the bottom of a reactor pressure vessel. In a control rod drive mechanism handling device that disassembles and assembles the control rod drive mechanism body and the bolts that fasten the housing, a fixed barrel is provided on the wrench device, and a displacement gauge is attached to the fixed barrel. And a target that can be measured by the displacement gauge is provided on the outer peripheral portion of the housing.

[0035]

According to the present invention, the wrench device on the bolt attaching / detaching device has the fixed cylinder fixed with the bolt, and the swing drive device is provided with the displacement gauge attached to the fixed cylinder. This turning drive device is provided with a drive pulse motor, and the displacement meter is adjusted to a target position by this motor.

The displacement meter can always check the exact position of the bolt attaching / detaching device and the housing by catching the disk provided as the target on the housing. The hollow piston and the control rod can be completely uncoupled by the detection of the displacement gauge. Therefore, it is possible to improve the reliability of the regular inspection work of the control rod drive mechanism.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a control rod drive mechanism handling device according to the present invention will be described with reference to FIGS. In addition,
In the figure, the same parts as in FIGS.

FIG. 1 shows a state in which the bolt attaching / detaching device 30 of the control rod drive mechanism handling device in this embodiment is arranged between the control rod drive mechanisms 2 and 2.

That is, the bolt attaching / detaching device 30 is lifted up to the housing 5 by a lift truck (not shown), and the bolt attaching / detaching device 30 is driven to perform a predetermined operation by the control rod drive mechanism 2, the spool piece 8a, the electric motor bracket 9, the electric motor. Install and remove 10.

The bolt attaching / detaching device 30 is provided with a position detecting device 31 for accurately detecting the positions of the control rod drive mechanism 2 and the wrench device 29 when the control rod drive mechanism 2 is replaced.

Next, the mechanism of the position detecting device 31 will be described with reference to FIGS. 2 and 3. FIG. 3 is A-A of FIG.
It is sectional drawing which cut | disconnected the arrow direction.

In FIG. 2, reference numeral 37 is a fixed barrel, and this fixed barrel 37 is fixed to a predetermined position of the wrench device 29. As shown in FIG. 3, the fixed body 37 has an upper ring 36 and a lower ring.
41 is attached, and a swing ring 35 is provided between the upper ring 36 and the lower ring 41 via a ball chain 42.

The swivel ring 35 is provided with a swivel drive device 40 which can be attached and detached with a fixing bolt 34. The swing drive device 40 is a displacement gauge 33 attached to a swing ring 35.
And a cover 38 surrounding this displacement meter 33, and this cover 38
Pulse motor 45, rotary shaft 46 and spur gear installed inside
It consists of 44 etc. The pulse motor 45 is a swing drive device.
Take out the rotation angle of 40.

A spur gear 44 is attached to the tip of the pulse motor 45 via a rotary shaft 46, and the spur gear 44 is meshed with a spur gear 43 provided on the fixed barrel 37. The wrench device 29 is provided with eight wrenches 39 as shown in FIGS.

The position detecting device 31 configured as described above operates as follows from a control room (not shown).

First, the bolt attaching / detaching device 30 is lifted to a predetermined position to drive the pulse motor 45, and then, as shown in FIGS.
The disk 32 is attached as a target to the housing 5 shown in FIG. 1, and the disk 32 is detected by the displacement meter 33.

The detected signal of the displacement gauge 33 is displayed on the control panel 48 via the amplifier unit 47 as shown in FIG. 6, and the operator confirms the position. Next, the bolts are removed by the bolt attaching / detaching device 30, and the control rod drive mechanism 2 is lowered to 3 mm between the housings 5.

Next, the bolt attaching / detaching device 30 is rotated by 45 °,
Check the uncoupling of the hollow piston 18 and the control rod 3.
The uncoupling state can be confirmed by attaching the disk 32 as a target at a position of 45 ° and detecting the disk 32 with the displacement meter 33.

Further, by determining the positions of the guide pin of the spool piece 8a, the guide pin of the electric motor bracket 9 and the guide pin of the electric motor 10 which are not shown on the basis of the disc 32 attached to the housing 5, they are applied to the respective alignment. You can

As shown in FIG. 2, the position detecting device 31 uses two fixing bolts 34 to easily rotate the driving device 40.
Can be installed and removed. Further, as shown in FIG. 3, the ball chain 42 is fixed to the swivel ring 35 by the upper ring 36 and the lower ring 41 to reduce friction and suppress the driving torque to a small motor. It becomes possible, and the weight of the device can be reduced.

[0051]

According to the present invention, since the position of the apparatus can be recognized even in the work at a position that cannot be visually confirmed, it is possible to improve the reliability of the handling work and the work efficiency.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which a bolt attaching / detaching device of a control rod drive mechanism handling device according to the present invention is arranged between control rod drive mechanisms.

FIG. 2 is a top view showing the position detection device in FIG.

3 is a vertical cross-sectional view taken along the line AA in FIG.

FIG. 4 is an enlarged perspective view showing a disk portion attached to the housing in FIG.

5 is a top view as seen from the direction of arrow BB in FIG. 4. FIG.

FIG. 6 is a block diagram showing the position detection device in FIG.

FIG. 7 is a vertical cross-sectional view showing a part of the lower part of the reactor pressure vessel in a side view.

8 is a vertical sectional view showing a control rod drive mechanism in FIG.

9 is a vertical cross-sectional view of a main part showing a coupling state of the control rod and bayonet in FIG. 7.

FIG. 10 is a transverse cross-sectional view taken along the line CC in FIG.

11 is a side view showing a state where the bolt attaching / detaching device used in FIG. 8 is arranged between the control rod drive mechanisms.

[Explanation of symbols]

1 ... Reactor pressure vessel, 2 ... Control rod drive mechanism, 3 ... Control rod, 4 ... Core, 5 ... Housing, 6 ... Mounting bolt, 7 ...
Outer tube, 8 ... Guide tube, 8a ..., Spool piece, 9 ... Motor bracket, 10 ... Electric motor, 11 ...
Rotation start shaft, 12 ... Gear device, 13 ... Rotation transmission shaft, 14 ... Drive screw, 15 ... Nut, 16 ... Roller, 17 ... Groove, 18 ... Hollow piston, 19 ... Bayonet coupling spat, 20 ... Latch, 21 … Inlet, 22… Labyrinth seal, 23… Disc spring, 24… Throttle, 25… Stop piston, 26… Control rod guide tube base, 27… Outer tube upper guide, 28… Coil spring, 29… Wrench device, 30… Bolt Attaching / detaching device, 31 ... Position detecting device, 32 ... Disc, 33 ... Displacement meter, 34
... Fixing bolt, 35 ... Swivel ring, 36 ... Upper ring, 37 ... Fixing barrel, 38 ... Cover, 39 ... Wrench, 40 ... Swivel drive device, 41
… Lower ring, 42… Ball chain, 43, 44… Spur gear, 45
… Pulse motor, 46… Rotation axis, 47… Amplifier unit, 48
…control panel.

Claims (1)

[Claims] 1. An electric motor, an electric motor bracket, a spool piece, a control rod drive mechanism main body, which constitutes a control rod drive mechanism, which is attached to a housing which is provided with a wrench device and a bolt attaching / detaching device and which penetrates through a bottom portion of a reactor pressure vessel. In the handling device of the control rod drive mechanism that detaches the bolts fastening the housing and disassembles and assembles it,
A control rod, wherein the wrench device is provided with a fixed barrel, a swing drive device having a displacement gauge attached to the fixed barrel is provided, and a target that can be measured by the displacement gauge is provided on an outer peripheral portion of the housing. Drive mechanism handling device.