JPS5925995B2 - Main steam pipe closure device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a main steam pipe, which is used when, for example, temporarily closing the inlet opening of the main steam pipe when a nuclear reactor is shut down to perform maintenance and inspection of safety valves, relief valves, etc. Relating to occlusion devices.

Generally, after a nuclear reactor has been in operation for a certain period of time, it is mandatory to stop the operation of the reactor and conduct maintenance inspections as part of a periodic inspection.

In this case, the outlet opening of the main steam pipe provided at the top of the pressure vessel is temporarily closed, and on the other hand, water is stored in advance up to the top of the pressure vessel to prevent exposure to radiation.

That is, after the core of the pressure vessel is completely submerged in water to reduce the leakage of radioactivity and prevent workers from being exposed to radiation,
We perform maintenance and inspection of various valve devices such as safety valves and relief valves installed in the main steam pipes.

Conventionally, this type of main steam pipe closing device has been installed so that it can be inserted into and removed from the openings (a) of a plurality of main steam pipes (2) bored in the upper part of a pressure vessel (1), as shown in FIG. This closure device is provided with a flexible ring seal C1, a flat hollow elastic seal body d, and a seal member e, respectively, on the outer periphery of a cylindrical support stopper body equipped with an air supply pipe a1 and a pressure supply pipe a2, and the above-mentioned ring The air supply pipe a1 is connected to the seal C and the hollow elastic seal body d.
are connected by each branch pipe f9g, thereby inserting the cylindrical support stopper into the opening ■a of the main steam pipe ■, and then supplying compressed air to the ring seal C and the hollow elastic seal d. It is supplied and expanded so that the opening na of the main steam pipe (2) can be closed.

However, the above-mentioned closure device for main steam pipes (2) is not only difficult to handle but also large in size because it is inserted into each of the openings (a) of a plurality of main steam pipes (1) and sealed tightly. Since this is a closure device, the work time becomes longer and there is a risk of being exposed to the radioactivity of the reactor. Unfortunately, when water pressure was applied to the main steam pipe (■) between the above-mentioned closure device and the above-mentioned safety valve, this closure device did not have the ability to withstand reverse pressure, so the water pressure caused the water to burst into the core of the pressure vessel. There is a risk.

In view of the above-mentioned points, the present invention enables a plug to be inserted into and removed from a main steam pipe, and enables the plug to withstand reverse pressure even when water pressure is applied to the main steam pipe. This invention relates to a main steam pipe closing device whose purpose is to quickly seal the pipes by simultaneously sealing them.

Hereinafter, the present invention will be described with reference to an illustrated embodiment. In FIGS. 2 to 6, reference numeral 1 denotes a pressure vessel in a boiling water reactor. Each opening 2a of the steam pipe 2 is provided to protrude outward, and a pair of guide rods 3 and a plurality of support members 4 are provided on the inner peripheral surface of the pressure vessel 1 (sixth
(see figure).

Each of the guide rods 3 is capable of vertically guiding a counter pressure support ring body 15, which will be described later, and each of the support members 4 regulates the horizontal position of the counter pressure support ring body 15. This counter pressure support ring body 15 is held.

On the other hand, inside the pressure vessel 1, a pair of crossed beam members 5 are connected to each main steam pipe 2 by means of respective ribs 6 and brackets 7.
It is designed to face the
Both beam members 5 of and are suspended by respective hanging ropes 9 connected to each of the ribs 6 and each of the hanging bolts 8 of the bracket 7, and the starting end of each of the hanging ropes 9 is above the pressure vessel 1. They are connected by a provided launcher (not shown).

Further, each cylinder device 11 is mounted on the frame 10 of each beam member 5.
A truck 13 equipped with each connecting member 12 is installed on the output shaft 11a of each cylinder device 11 so as to be able to run on each of the beam members 5.

In addition, this trolley 13 has a pair of front and rear wheels (rollers).
13a and guide pieces 13b, and a plug 14 is provided at the front end of the trolley 13 so that it can be fitted into the opening 2a of the main steam pipe 2 and can be removed. .

Furthermore, this plug 14 is attached to the outer periphery of a cylindrical support stopper 14b equipped with an air feed pipe 14a and a pressure feed pipe (not shown).
The plug 14 is composed of a ring seal 14c, a hollow elastic seal body 14d, and a seal member 14e, and after the plug 14 is inserted into the opening 2a of the main steam pipe 2, the ring seal 14c and the hollow elastic seal body Compressed air is supplied from the air supply pipe 14a to 14d and expanded, thereby making it possible to close the opening 2a of the main steam pipe 2 in a watertight manner.

On the other hand, a counter pressure support ring body 15 that can be divided into four is disposed at the outer end of the beam member 5, and a retaining hole 15a of the counter pressure support ring body 15 is provided with the beam member 5. They are connected and fixed by a locking rod 16 attached to the lower part of the.

Further, this locking rod 16 is adapted to engage with the retaining hole 15a by a cylinder device (actuator) 17 provided at the lower part of the beam member 5.

Further, on the outer periphery of the counter pressure support ring body 15, a pair of guide plates 18 and a plurality of support brackets 1 are provided.
9 are attached, each guide plate 18 fits into each of the guide rods 3, and each of the other support brackets 19 can be placed on each of the support members 4.

Furthermore, each lock par 20 is fitted into the lower part of the counter pressure support ring body 15 located directly below each of the plugs 14 so as to be able to move forward and backward in the vertical direction.
The lower end of the IJ ring body 15 extends so that it can be operated by each cylinder device (actuator) 21 provided on the IJ ring body 15.

(Refer to Fig. 2) o Therefore, when the plug 14 is inserted into the opening 2a of the main steam pipe 2, each locker 20 is advanced upward by each cylinder device 21, and is thereby inserted into the plug 14. Even if a reverse pressure is applied, this plug 14 will not easily pop out into the pressure vessel 1.

Hereinafter, the effects of the present invention will be explained.

The reactor core of the pressure vessel 1 is flooded in advance and prepared to receive radiation exposure during work.

Next, the beam members 5 suspended by the respective hanging ropes 9 of a launcher (not shown) are suspended into the pressure vessel 1.

In this case, the counter pressure support ring body 15 is assumed to be connected by each locking rod 16 that is engaged by the cylinder device 17, as described above.

When the counter pressure support ring body 15 that forms a pair with the beam member 5 is lowered by the hanging rope 9, each guide plate 18 of the counter pressure support ring body 15 is lowered while being vertically positioned by each guide rod 3. do.

Then, each support bracket 19 of the counter pressure support ring body 15 is placed in contact with each support member 4, so that each plug 14 on each beam member 5 is placed in the opening 2a of each main steam pipe 2. It will be in a state where it can be fitted.

Next, when each cylinder device 11 is driven, each truck 13
Each upper plug 14 is inserted into the opening 2a of each main steam pipe 2.

As described above, each plug 14 is connected to the ring seal 14c and the hollow elastic seal body 14d in the air pipe 14.
Supply compressed air from a to cause expansion, thereby
The opening 2a of the main steam pipe 2 is watertightly closed (see FIG. 4).

In this way, each plug 14 is inserted into the opening 2a of each main steam pipe 2 at the same time.

When each plug 14 is inserted into each main steam pipe 2, each connecting member 12 of each truck 13 is removed from each plug 14, and each truck 13 is pulled back to its original position by each cylinder device 11.

Thereafter, each lockper 20 is advanced upward by each cylinder device 21 and stopped perpendicular to the back wall of each plug 14, so that even if water pressure is applied to the main steam pipe 2 and a pressure test is performed, no clogging occurs. Even if reverse pressure is applied, there is no fear that each plug 14 will fly out into the core of the pressure vessel 1.

On the other hand, when each beam member 5 becomes an obstacle during a periodic inspection of the core inside the pressure vessel 1, as shown in FIG.
Each locking rod 16 is connected to the retaining hole 1 by each cylinder device 17.
5a, and then the upper part of each beam member 5 can be pulled up and removed by the lifting rope 9 of the launch machine (see FIG. 5).

Further, when inspecting each jet pump installed near the pressure vessel 2, if the counter pressure support ring body 15 becomes an obstacle, the counter pressure support ring body can be removed.

In this case, each plug 14 can be hermetically sealed within the opening 2a of each main steam pipe 2 (see FIG. 6).

As described above, according to the present invention, a beam member 5 is horizontally suspended by a hanging rope 9 in a pressure vessel 1 equipped with a main steam pipe 2, and a counter pressure support is provided at the outer end of the beam member 5. ring 15
is detachably provided, and a cylinder device 1 is mounted on the beam member 5.
1 is attached, and the main steam pipe 2 is connected to this cylinder device 11.
A plug 14 that can be inserted into and removed from the opening 2a is provided so as to be removable via the trolley 13, and the lock par 20 can be moved vertically forward and backward from the counter pressure support ring 15 located directly below the plug 14. When the plug 14 is inserted into the opening 2a, the plug 1
Since the locking device 20 is arranged to extend perpendicularly to the back wall of each plug 14, even if water pressure is applied when each plug 14 is closed, there is no risk that this plug 14 will be accidentally pulled out, and it also prevents the plug 14 from being accidentally pulled out. Since each plug can be inserted into the steam pipe 2 at the same time, the work efficiency is quick and there is no risk of exposure to radiation, which has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional main steam pipe closing device, FIG. 2 is a sectional view of a main steam pipe closing device according to the present invention, FIG. 3 is a plan view of the present invention, and FIGS. 4 to 6 2A and 2B are diagrams for explaining the present invention in detail. DESCRIPTION OF SYMBOLS 1... Pressure vessel, 2... Main steam pipe, 5... Beam member, 9... Hanging rope, 11... Cylinder device, 13
... Trolley, 14... Plug, 15... Counter pressure support ring body, 16... Locking rod, 20... Lock par, 21°° cylinder device.

Claims (1)

[Scope of Claims] 1. A beam member is horizontally suspended by a hanging rope in a pressure vessel equipped with a main steam pipe, and a counter pressure support ring is detachably provided at the outer end of the beam member. A cylinder device is attached to the member, and a plug that can be inserted into and removed from the opening of the main steam pipe is provided on the cylinder device so as to be removable via a trolley, and the above-mentioned counter pressure located directly below the plug is provided. A lock bar is fitted into the support ring so as to be vertically movable and retractable, and when the plug is inserted into the opening, the lock bar extends perpendicularly to the back wall of the plug. main steam pipe closure device. 2. Blocking of the main steam pipe according to claim 1, characterized in that the plug is placed on a truck that runs on a beam member, and the plug can be inserted into and removed from the main steam pipe using a cylinder device. Device. 3. Claims 1 or 2, characterized in that during a reverse pressure test, the plug is temporarily fixed by allowing the lock bar of the reverse pressure support ring body to move forward and backward using an actuator. Main steam pipe closure device as described