JP2000098080A - Piping plug device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piping plug device capable of quickly and reliably plugging an arbitrary position of the piping for performing checking and repairing works of the piping constituting jet pumps of a boiling water reactor. SOLUTION: Provided are a plug device body 50 placed in piping for plugging a pipe, a body handling tool 51 for moving the plug device body 50 to a desired position in the piping and a connection mechanism 65 for detachably connecting the plug device body 50 and the body handling tool 51. The plug device body 50 has a seal member 52 capable of pressing on the inner surface of piping by swelling out in the radial direction of the piping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe plug apparatus, and more particularly to a pipe plug apparatus installed inside a pipe disposed in a reactor pressure vessel of a boiling water reactor (BWR).

[0002]

2. Description of the Related Art FIG. 7 is a longitudinal sectional view showing a schematic configuration of a reactor pressure vessel of a BWR and its internal structure. A coolant 2 exists inside the reactor pressure vessel 1, and a core 3 is submerged in the coolant 2. The core 3 is composed of a plurality of fuel assemblies (not shown) and is housed in a core shroud 10.

[0003] The coolant 2 flows upward through the core 3, and at this time, the temperature is increased by the nuclear reaction heat of the core 3, and a two-phase flow of water and steam is formed. The two-phase coolant 2 flows into the steam separator 4 installed above the reactor core 3, where it is separated into water and steam. Among them, the steam is introduced into a steam dryer 5 installed above the steam separator 4, and is dried to become dry steam. The dried steam is transferred to a steam turbine (not shown) via a main steam pipe 6 connected to the reactor pressure vessel 1 and is used for power generation.

On the other hand, the separated water flows down the core 3 through the downcomer 7 between the core 3 and the reactor pressure vessel 1. A plurality of control rod guide tubes 8 are provided below the core 3, and control rods (not shown) are inserted into or pulled out of the core 3 via the control rod guide tubes 8.

A control rod drive mechanism 9 is provided below the control rod guide tube 8, and controls the insertion and withdrawal of the control rod into and from the reactor core 3 by the control rod drive mechanism 9. In the downcomer section 7, a plurality of jet pumps 11 are installed at equal intervals along the circumferential direction of the reactor.

[0006] A reactor recirculation pump (not shown) is provided outside the reactor pressure vessel 1, and includes a reactor recirculation pump, a jet pump 11, and a reactor recirculation piping ( (Not shown)) constitutes a reactor recirculation system. That is, the driving water of the jet pump 11 is supplied by the reactor recirculation pump, and the coolant 2 is forcibly circulated into the core 3 by the action of the jet pump 1.

FIG. 8 is a perspective view showing a portion of a jet pump 11 in the reactor pressure vessel 1, and FIG. 9 is a diagram showing a transition piece and an elbow. As shown in FIGS. 8 and 9, the jet pump 11 has a riser pipe 12 at the center, and the riser pipe 12 supplies the coolant supplied from the reactor recirculation pump to the reactor pressure via the recirculation inlet nozzle 13. It is designed to be introduced into the container 1.

A pair of elbows 15A and 15B are connected to the upper part of the riser tube 12 via a transition piece 14. A pair of inlet throats 17A, 17B are connected to the pair of elbows 15A, 15B via a pair of mixing nozzles 16A, 16B.

These inlet throats 17A, 17
Diffusers 18A and 18B are connected to the lower part of B, respectively, and when the coolant 2 is jetted from the upper mixing nozzles 16A and 16B, the reactor water is drawn in from the surroundings.

The injected coolant 2 and the entrapped reactor water are mixed in the inlet throats 17A and 17B, and thereafter, the hydrostatic head is recovered by the diffusers 18A and 18B.

In the above configuration, the flow of the coolant sent from the reactor recirculation pump causes fluid vibration. To cope with this, the riser pipe 12 has its lower end welded to the recirculation inlet nozzle 13. The upper end is fixed to the reactor pressure vessel 1 via a riser brace 20. In FIG. 8, reference numeral 36 denotes a riser bracket.

The inlet throats 17A and 17B have mixing nozzles 16A and 16B and vents 15A and 15B at their upper ends.
And is mechanically connected to the transition piece 14 via the lower end, and the lower end is inserted into the upper end of the diffusers 18A and 18B. As described above, both the riser pipe 12 and the inlet throats 17A and 17B are configured in consideration of the occurrence of the fluid vibration, and have a configuration capable of sufficiently coping with the fluid vibration.

FIG. 10 is a perspective view showing the structure near the riser pipe 12. As shown in FIG. 10, a pad 39 is formed on the inner wall of the reactor pressure vessel 1. As shown in FIG. Pad 39
, Four thin plates 40 are welded, and the thickness of the thin plates 40 is about 10 mm. The tip of the four thin plates is block 4
1 and are integrally formed with each other through the riser pipe 12.
Is inside the block 41 (on the inner wall surface of the reactor pressure vessel 1)
Welded to.

The riser brace 20 is connected to the riser tube 1.
2 suppresses fluid vibration during the operation of the reactor and absorbs a difference in thermal expansion between the reactor pressure vessel 1 made of carbon steel and the riser pipe 12 made of austenitic stainless steel. Therefore, during the operation of the reactor, the reactor is in a deformed state absorbing the difference in thermal expansion.

[0015]

In the above configuration,
For example, rust, cracks, or the like may occur on the inner surface of the riser tube 12 for some reason. The riser tube 12
Austenitic stainless steel pipes are mainly used as the material for the steel, so stress corrosion cracking (SCC) occurs when the three conditions of stress, corrosion environment, and material (chromium-depleted layer) are satisfied.
And the riser pipe 12 may be damaged.

Since stress corrosion cracking does not occur if any one of the above three conditions is missing, various measures must be taken in consideration of the above three conditions in order to prevent stress corrosion cracking. is there.

When rust or cracks are generated on the surface of the jet pump 11 for some reason, if the rust or cracks are left undisturbed, the cracks may progress and the jet pump 11 may crack. The fact that the jet pump 11 that controls the power of the nuclear reactor becomes such a state is as follows.
It can also have a negative effect on other structures,
Such damage to the jet pump 11 must be avoided.

The present invention has been made in consideration of the above-described circumstances. For example, in order to perform inspection and repair work on a pipe constituting a jet pump of a boiling water reactor, an arbitrary position in the pipe is determined. It is an object of the present invention to provide a piping plug device that can be quickly and reliably plugged.

[0019]

In order to solve the above-mentioned problems, a pipe plug device according to the present invention includes a plug device main body installed in a pipe for plugging the pipe, and a plug device main body provided in the pipe. A main body handling tool for moving to a desired position, and a connecting mechanism for detachably connecting the plug device main body and the main body handling tool, wherein the plug device main body swells in a radial direction of the pipe to form a pipe. It is characterized by having a seal member that can be pressed against the inner peripheral surface.

Further, it is preferable that the connecting mechanism connects the plug device main body and the main body handling tool so as to swing.

Further, it is preferable that a posture holding member projecting from the plug device main body before and after the seal member and contacting the inner surface of the pipe is further provided.

Further, the posture holding member has a guide roller which resiliently contacts an inner surface of the pipe, and the guide roller is provided on the inner surface of the pipe when the plug device body is moved in the pipe. It is desirable to roll.

Preferably, the seal member is an annular seal member having an outer diameter smaller than the inner diameter of the pipe before swelling and larger than the inner diameter of the pipe after swelling.

Further, when the plug device main body is installed inside a vertical pipe, the weight of the plug device main body can be supported by a frictional force between the seal member pressed against the inner surface of the pipe and the inner surface of the pipe. Is desirable.

The seal member is formed of a flexible hollow member which expands in the radial direction of the pipe when a pressurized fluid is supplied to the inside thereof, and is supplied to the inside of the flexible hollow member. It is preferable that a tank filled with a pressurized fluid and a valve that is remotely opened when the pressurized fluid in the tank is introduced into the flexible hollow member be provided in the plug device main body.

A drain passage formed through the plug device main body, a drain hose connected to communicate with the drain passage, and a drain passage provided in the drain passage or in the drain hose. And a water shutoff valve.

Further, it is desirable that the drainage hose is connected to be pivotable via a slip joint.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Hereinafter, a pipe plug device according to a first embodiment of the present invention will be described with reference to FIGS. The pipe plug device according to the present embodiment is installed in a pipe inside a reactor pressure vessel of a boiling water reactor, particularly in a riser pipe 12 (see FIGS. 8 to 10).

FIGS. 1 and 2 are a longitudinal sectional view and a plan view, respectively, of the piping plug device according to the present embodiment, showing a state in which the plug device main body 50 and the main body handling tool 51 are detachably connected by a connecting mechanism 65. ing.

The coupling mechanism 65 includes a spherical grip (projecting member) 56 projecting from the rear end of the plug device main body 50 and a plurality of hooks 60 for gripping the grip 56 releasably. ing. The hook 60 is remotely opened and closed by an air cylinder 62 connected to a lever 61, and forms a concave member that holds the grip portion 56 when closed.

By holding the spherical holding portion 56 with the plurality of hooks 60, the plug device main body 50 and the main body handling tool 51 are swingably connected.

The plug device main body 50 is a sealing member 52 which swells in the radial direction of the pipe and can be pressed against the inner peripheral surface of the pipe.
The seal member 52 is constituted by an annular seal tube provided on the plug device main body 50 so as to be coaxial with the pipe axis of the pipe.

The outer diameter of the seal tube 52 is smaller than the inner diameter of the pipe before bulging (right state in FIG. 1), and is larger than the inner diameter of the pipe after bulging (left state in FIG. 1). Is set.

At the front and rear of the seal tube 52, three posture holding members 66 are protruded from the plug device main body 52, and each posture holding member 66 comprises a guide roller 53, a spring 55, and a cylinder 54. The guide roller 53 is elastically contacted with the inner surface of the pipe by the elastic force of the spring 55. Also, the guide roller 53
The spring 55 can be driven forward and backward by a cylinder 54, and is normally housed by the cylinder 54.

The guide roller 53 is connected to the plug device main body 50.
Rolls on the inner surface of the pipe when it is moved in the pipe, whereby the plug device main body 50 moves smoothly.
Further, since the guide roller 53 is resiliently abutted on the inner surface of the pipe by the spring 55, the plug device main body 50 can be moved smoothly even when the inner surface of the pipe has an uneven portion.

When the plug device main body 50 is installed at a desired position in the pipe, the attitude of the plug device main body 50 is inclined with respect to the pipe axis of the pipe by the guide rollers 53 abutting on the pipe inner surface. Not to be kept.

The seal tube (seal member) 52 is a flexible hollow member that expands in the radial direction when a pressurized fluid, preferably compressed air, is supplied to the inside thereof. A tank chamber 57 filled with compressed air supplied to the inside of the seal tube 52 is formed in an airtight structure inside the plug device main body 50.

Further, at the front end (upper side in FIG. 1) of the plug device main body 50, when the pressurized fluid in the tank chamber 57 is introduced into the seal tube 52 and the pressurized fluid in the seal tube 52 is released to the atmosphere. A valve 59 is provided which is opened by remote control when it is pulled out to the side.

The valve 59 has a double-structured push-up rod 5 that penetrates through the spherical holding portion 56 of the connecting mechanism 65 and protrudes downward.
By pushing up the member inside 8, the inside of the seal tube 52 and the tank chamber 57 are opened so as to communicate with each other.

On the other hand, by pushing up the member outside the double push-up bar 58, the valve 59 is opened so that the inside of the seal tube 52 and the atmosphere side communicate with each other.

Here, the push-up operation of the push-up rod 58 is performed by the small cylinder 6 provided at the center of the body handling tool 51.
3, and a pin 64 which is exchangeably incorporated into the tip of the cylinder 63.

By preparing two types of pins 64 having different diameters and replacing the pins 64 as appropriate, either one of the members inside and outside the push-up bar 58 can be pushed up selectively. .

When the valve 59 is opened by the member inside the push-up rod 58, the compressed air in the tank chamber 57 is sent into the inside of the seal tube 52 through a tube (not shown), and the seal tube 52 expands in the radial direction. I do. The radially swelled seal tube 52 is pressed against the inner peripheral surface of the pipe to exhibit a sealing function.

Next, a case where the riser pipe 12 of the boiling water reactor is plugged using the pipe plug device according to the present embodiment will be described with reference to FIGS.

When the pipe plug device according to the present embodiment is inserted into the riser tube 12, a plug (not shown) is previously attached inside the furnace, and the inside of the riser tube 12 is already in the air state. ing. The plugging operation using the piping plug device according to the present embodiment is performed after opening the external piping of the reactor pressure vessel.

FIG. 3 shows the recirculation inlet nozzle 1 with the plug device main body 50 and the main body handling tool 51 connected to each other.
FIG. 5 is a diagram showing a state in which the connector is inserted from No. 3 (see FIG. 4) and passes through the elbow section 42.

First, when installing the plug device main body 50, the tank chamber 57 is filled with compressed air in advance. Then, with the plug device main body 50 and the main body handling tool 51 connected to each other, the pipe plug device according to the present embodiment is inserted into the narrow inlet of the recirculation inlet nozzle 13 and passed through the elbow portion 42.

Here, since the plug device main body 50 and the main body handling tool 51 are swingably connected by the connecting mechanism 65, they can pass through the elbow portion 42 without any trouble.

FIG. 4 shows a state in which the plug device main body 50 and the main body handling tool 51 are connected to each other, inserted from the recirculation inlet nozzle section 13 and passed through the elbow section 42, and then inserted into the riser pipe 12 which is a vertical pipe. It is the figure which showed the state which pushed up.

That is, the plug device main body 50 that has passed through the elbow portion 42 is further pushed in from the rear by the main body handling tool 51 and is pushed up to a predetermined position in the riser tube 12.

When the plug device main body 50 reaches a predetermined position, the cylinder 63 of the main body handling tool 51 is operated by remote control, the member inside the push-up bar 58 is pushed up by the pin 64, and the valve 59 is opened.

When the valve 59 is opened, the tank chamber 57
Is supplied into the seal tube 52, and the seal tube 52 expands in the radial direction. The bulged seal tube 52 is pressed against the inner peripheral surface of the riser tube 12 to exhibit a sealing function, thereby closing the riser tube 12.

Here, the plug device body 50 is lightweight so that the weight of the plug device body 50 can be supported by the frictional force between the seal tube 52 pressed against the inner surface of the riser tube 12 and the inner surface of the riser tube 12. It has a structure.

Further, since the posture of the plug device main body 50 is held by the posture holding member 66 so as not to be inclined with respect to the tube axis of the riser tube 12, the sealing function by the seal tube 52 can be reliably obtained.

When the seal tube 52 expands, the cylinder 62 is driven to operate the lever 61, the hook 60 is opened to release the grip portion 56, and the connection between the plug device main body 50 and the main body handling tool 51 is released. To separate them. Then, only the main body handling tool 51 is pulled out and carried out of the recirculation inlet nozzle 13.

Since the inside of the riser pipe 12 is plugged by the plug device main body 50 in this manner, even when reactor water leaks from a plug (not shown) attached inside the furnace, the leak water is shut off by the plug device main body 50. Is done. In addition, dew condensation water generated inside the riser pipe 12 also
It is shut off by the plug device main body 50.

Therefore, preventive maintenance work and inspection of the inside of the recirculation inlet nozzle 13 and the elbow section 42 can be performed safely and reliably in the air state.

It should be noted that a plurality of plug device main bodies 50 can be installed inside the riser tube 12 by preparing a plurality of plug device main bodies 50 in advance and repeating the above-described installation work. Thus, the plurality of plug device main bodies 50
The reliability of the sealing function can be enhanced by installing the seal.

The plug device main body 50 is connected to the riser tube 12.
In order to remove from the inside, a procedure reverse to the above-described mounting procedure may be performed. At this time, the seal tube 52
In order to remove the compressed air from the inside, the pin 64 is replaced in advance with a large diameter one. Then, the member outside the push-up bar 58 is pushed up to open the valve 59, and the compressed air in the seal tube 52 is released to the atmosphere.

As described above, according to the piping plug apparatus of the present embodiment, the plug apparatus main body 50 is installed and plugged inside the riser pipe 12 of the boiling water reactor, so that the furnace Even if the reactor water leaks from the plug, the leak water can be reliably shut off. Therefore, it is possible to perform preventive maintenance work and inspection of the inside of the recirculation inlet nozzle 13 and the elbow section 42 in the air state while maintaining the full water state without draining the furnace water.

As described above, since the maintenance work can be performed in the aerial state, the maintenance work can be performed with sufficient care, and the soundness and reliability of the reactor can be improved. The operation rate can be improved.

Further, since the maintenance work can be performed without draining the furnace water in the furnace, the radiation exposure dose of the workers can be greatly reduced.

Further, according to the piping plug device of the present embodiment, since the sealing tube 52 is plugged by expanding in the radial direction, the sealing tube 52 can be detachably attached to an arbitrary position in the piping. The installation work of the plug device main body 50 can be performed in a short time.

Further, since the tank chamber 57 is provided inside the plug device main body 50 and the seal tube 52 is inflated with the compressed air filled in the tank chamber 57, the size of the pipe plug device can be reduced. The installation work of the plug device main body 50 can be performed in a short time.

Second Embodiment Next, a pipe plug device according to a second embodiment of the present invention will be described with reference to FIGS. Note that the present embodiment is obtained by partially adding a configuration to the above-described first embodiment, and hereinafter, portions different from the above-described first embodiment will be described.

As shown in FIGS. 5 and 6, the pipe plug device according to the present embodiment has a drain passage 70 formed through the plug device main body 50 back and forth (up and down in FIG. 5). The front end of the drain passage 70 is provided with a drain port 71.
Is formed.

On the other hand, a drain hose 72 is connected to the rear end of the drain passage 70, and a water stop valve 73 is provided in the middle of the drain hose 72. Here, it is desirable that the drainage hose 72 be pivotably provided via a slip joint having a pivotable structure.

According to the piping plug apparatus of the present embodiment having the above configuration, when the reactor water leaks from a plug (not shown) installed inside the furnace or when dew water is generated inside the riser pipe 12, By opening the water stop valve 72, the leak water or the dew water can be drained from the drain passage 70 and the drain hose 72.

For this reason, it is not necessary to remove the plug device main body 50 each time to drain the leak water or the dew water, and the working time can be greatly reduced.

The drain hose 7 is connected via a slip joint.
If 2 is mounted so as to be freely rotatable, there is no fear of being caught during installation work or the like, and the work can be performed smoothly.

[0071]

As described above, according to the pipe plug device of the present invention, since the seal member which is swelled in the radial direction and can be pressed against the inner peripheral surface of the pipe is provided, an arbitrary position of the pipe can be set. The plug can be quickly and reliably plugged.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a piping plug device according to a first embodiment of the present invention.

FIG. 2 is a plan view showing the piping plug device according to the first embodiment of the present invention.

FIG. 3 is a view showing a state in which a plug device main body of the pipe plug device according to the first embodiment of the present invention passes through an elbow portion.

FIG. 4 is a view showing a state in which a plug device main body of the pipe plug device according to the first embodiment of the present invention is mounted at a desired position in a riser pipe.

FIG. 5 is a longitudinal sectional view showing a piping plug device according to a second embodiment of the present invention.

FIG. 6 is a plan view showing a piping plug device according to a second embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a schematic configuration of a boiling water reactor.

FIG. 8 is a perspective view showing a jet pump of a boiling water reactor and its periphery.

FIG. 9 is a front view showing a transition piece and an elbow portion of the boiling water reactor.

FIG. 10 is a perspective view showing a riser brace and a riser pipe of the boiling water reactor.

[Explanation of symbols]

 Reference Signs List 50 Plug device main body 51 Main body handling tool 52 Seal tube (seal member) 53 Guide roller 56 Gripping portion 57 Tank chamber 58 Push-up rod 59 Valve 60 Hook 64 Pin 65 Connecting mechanism 66 Posture holding member 70 Drainage channel 71 Drainage port 72 Drainage hose

Claims (9)

[Claims] 1. A plug device main body installed in a pipe for plugging a pipe, a main body handling tool for moving the plug device main body to a desired position in the pipe, and the plug device main body and the main body handling tool. And a connecting mechanism for detachably connecting the plug and the plug device, wherein the plug device main body has a seal member which swells in the radial direction of the pipe and can be pressed against the inner peripheral surface of the pipe. 2. The piping plug device according to claim 1, wherein the connection mechanism connects the plug device main body and the main body handling tool so as to swing. 3. The piping according to claim 1, further comprising a posture holding member projecting from the plug device main body before and after the sealing member and abutting against an inner surface of the piping. Plug device. 4. The position holding member has a guide roller resiliently abutting on the inner surface of the pipe, and the guide roller is provided on the inner surface of the pipe when the plug device body is moved in the pipe. The pipe plug device according to claim 3, wherein the pipe is rolled. 5. The seal member according to claim 1, wherein the seal member is an annular seal member having an outer diameter smaller than the inner diameter of the pipe before the expansion and larger than the inner diameter of the pipe after the expansion. The piping plug device according to any one of claims 1 to 4. 6. When the plug device main body is installed inside a vertical pipe, the self-weight of the plug device main body can be supported by a frictional force between the seal member pressed against the inner surface of the pipe and the inner surface of the pipe. The piping plug device according to any one of claims 1 to 5, characterized in that: 7. The seal member is made of a flexible hollow member that swells in the radial direction of the pipe when a pressurized fluid is supplied to the inside thereof, and is supplied to the inside of the flexible hollow member. A tank filled with a pressurized fluid and a valve that is remotely opened when the pressurized fluid in the tank is introduced into the flexible hollow member are provided in the plug device main body. The piping plug device according to any one of claims 1 to 6. 8. A drain passage formed through the plug device main body, a drain hose connected to communicate with the drain passage, and provided in the drain passage or in the middle of the drain hose. The piping plug device according to any one of claims 1 to 7, further comprising a water stop valve. 9. The piping plug device according to claim 8, wherein said drain hose is pivotally connected via a slip joint.