JP2000314796A - How to repaint the suppression chamber - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To advance the steps required for repainting a suppression chamber. A downcomer (12) and a vent header (11) are used to transfer water (5) from a suppression chamber (6) to the outside.
The inner surface of the vent header 11 and the inner surface of the vent pipe 14 are closed in a state where the connection part between the vent header 11 and the vent well 14 is closed by the expansion plug 15 and the connection part between the vent pipe 14 and the dry well of the containment vessel 4 is closed by the closing cover 16. After the existing coating film is removed by polishing, the paint is applied to the polished surface to form a new coating film. After the transfer of the water 5 from the suppression chamber 6 to the outside is completed, the suppression chamber 6 is removed.
The inner coating surface, the outer surface of the vent header 11, the inner surface and the outer surface of the downcomer 12, and the outer surface of the outer surface of the portion of the vent pipe 14 located in the suppression chamber 6 are removed by polishing. Apply to form a new coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repainting a suppression chamber.

[0002]

2. Description of the Related Art FIG. 3 shows an example of nuclear reactor equipment.
This reactor equipment includes a reactor pressure vessel 1 as a steam generation source.
A containment vessel body 2 having an open upper end and a top lid 3 for closing the opening of the containment vessel body 2, and a containment vessel 4 for containing the reactor pressure vessel 1, and a containment vessel 4 And a torus-shaped suppression chamber 6 which surrounds the lower part in the circumferential direction and stores water 5 therein.

The suppression chamber 6 is formed by connecting a plurality of segments 7 endlessly, has a detachable closing lid 8 on the top of a predetermined segment 7, and suppresses the suppression when performing a periodic inspection. A manhole 9 for an operator to enter and leave the chamber 6 and a nozzle 10 to which a piping (not shown) of a supply / exhaust system to the suppression chamber 6 is provided.

In the suppression chamber 6, there are provided a vent header 11 extending in the circumferential direction, and a number of downcomers 12 connected to the vent header 11 such that the lower end is submerged in the water 5.

[0005] Also, at a predetermined location of the vent header 11,
A valve 13 capable of allowing air to flow from the outside to the inside of the vent header 11 according to the pressure difference is attached.

Further, the internal space of the vent header 11 communicates with the internal space (dry well) of the containment vessel 4 via a vent pipe 14 penetrating through the suppression chamber 6.

The inner surface of the suppression chamber 6, the inner surface and the outer surface of the vent header 11, the inner surface and the outer surface of the downcomer 12, the inner surface of the vent tube 14, and the outer surface of the portion of the vent tube 14 located inside the suppression chamber 6 have a rust-preventive effect. Although it is coated with a high inorganic zinc-rich paint and an epoxy resin paint having excellent water resistance, the suppression chamber 6, the vent header 11,
In order to prevent the downcomer 12 and the vent pipe 14 from being corroded, repainting work for updating these coatings is carried out at the time of periodic inspection of the reactor equipment.

In the repainting work, as shown in the lower step of FIG. 2, a draining operation for transferring the water 5 in the suppression chamber 6 to the outside, a scaffolding material being carried into the suppression chamber 6 from the manhole 9, and the work is performed. A scaffold assembly work for erection of a scaffold, an inner surface of the suppression chamber 6, an inner surface and an outer surface of the vent header 11, an inner surface and an outer surface of the downcomer 12, an inner surface of the vent pipe 14, and an outer surface of a portion of the vent pipe 14 located in the suppression chamber 6. A sandblasting operation for removing the existing coating film formed by sandblasting and spraying the coating material to form a new coating film, a scaffold removal operation for dismantling the work scaffolding, and removing the scaffolding material from the manhole 9. Work in order.

After a curing period until the newly formed coating film is cured, the water 5 is returned into the suppression chamber 6.

[0010]

However, the total area of the polishing and painting work for each of the above-described suppression chamber 6, vent header 11, downcomer 12, and vent pipe 14 is very large, and repainting is performed during the periodic inspection period. In order to complete the construction, it is necessary to prepare a large number of sandblasters and spray coaters, and arrange an operator to operate these devices.

In addition, in recent years, there has been a demand in recent years to shorten the period of the periodic inspection to improve the operation efficiency of the nuclear reactor facility.

The present invention has been made in view of the above circumstances, and has as its object to advance the steps required for repainting a suppression chamber.

[0013]

According to a first aspect of the present invention, there is provided a method for repainting a suppression chamber, wherein the water is transferred from the suppression chamber to the outside before or during the transfer. Then, after the existing coating on the inner surface of the vent header disposed in the suppression chamber and the inner surface of the vent pipe communicating with the vent header is removed by polishing, a paint is applied to the cleaned surface to form a new coating. After forming and completing the transfer of water from the suppression chamber to the outside, the existing coating on the inner surface of the suppression chamber, the outer surface of the vent header, the inner and outer surfaces of the downcomer, and the outer surface of the portion of the vent tube located within the suppression chamber is provided. After the film is polished and removed, a paint is applied to the polished surface to form a new coating film.

Further, in the method for repainting the suppression chamber according to the second aspect of the present invention, before or during the transfer of water from the suppression chamber to the outside, the lower end is immersed in the water in the suppression chamber. The connection between the downcomer and the vent header arranged in the suppression chamber is closed, and the connection between the vent pipe communicating with the vent header and the dry well of the containment vessel is closed. After removing the existing coating on the inner surface of the header and the inner surface of the vent pipe, apply a paint to the cleaned surface to form a new coating,
After the transfer of water from the suppression chamber to the outside is completed, the existing coating on the inside of the suppression chamber, the outside of the vent header, the inside and outside of the downcomer, and the outside of the part of the vent pipe located inside the suppression chamber is ground. After the cleaning, the paint is applied to the polished surface to form a new coating film.

In any of the suppression chamber repainting methods according to the first and second aspects of the present invention, the blast cleaning operation is usually performed on the inner surface of the vent header and the inner surface of the vent pipe which are not immersed in water. It is installed before or during the transfer of water from the suppression chamber to the outside, and the steps required for repainting the suppression chamber are advanced.

In the method for repainting a suppression chamber according to a second aspect of the present invention, the connection between the downcomer and the vent header and the connection between the vent pipe and the dry well of the containment vessel are each closed. In addition, dust generated during the abrasive coating operation is prevented from scattering to the suppression chamber and the dry well of the containment vessel.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an embodiment of a method for repainting a suppression chamber according to the present invention. In FIG. 1, the same reference numerals as in FIG. 3 denote the same parts.

In this method of repainting the suppression chamber, a balloon-shaped inflatable plug 15 formed into a shape that can be inserted into the downcomer 12 by a synthetic rubber material having a high elasticity, and the like, and a vent tube 14 on the side of the storage container body 2 And a closing cover 16 capable of covering the opening of the connection end of the above.

In the repainting work, as shown in the upper stage of FIG. 2, in parallel with the draining operation for transferring the water 5 in the suppression chamber 6 to the outside, the inner surface of the vent header 11 and the inner surface of the vent pipe 14 are removed. Constructs the brushing work.

In this blasting work, as shown in FIG. 1, the valve 13 is opened, and the blasting material supply pipe 18 of the sandblast blasting device 17 and the blasting material suction of the blasting material recovery device 19 are sucked. The pipe 20, the dust suction pipe 22 of the dust collector 21, and the paint supply pipe 24 of the spray coater 23 are drawn into the vent header 11 from outside the suppression chamber 6 via the manhole 9 and the body of the valve 13.

Next, the expansion plug 15 is connected to each downcomer 1.
2 and pressurized to the inner surface of the downcomer 12 by applying air pressure to the expansion plug 15 so that each downcomer 1
The communication between 2 and the vent header 11 is closed.

Each vent pipe 1 is closed by a cover 16.
4 are sequentially covered, the communication between each vent pipe 14 and the dry well of the reactor containment vessel 4 is closed, and all the vent pipes 14 and the reactor containment vessel 4 are closed. Before closing the communication with the drywell, an operator enters the inside of the vent header 11 and the cleaning material supply pipe 18 is closed.
The polishing nozzle (not shown) attached to the tip of the nozzle is operated for a predetermined time, and the inner surface of the vent header 11 and the vent pipe 1 are operated.
After peeling off the existing coating film on the inner surface of No. 4, the paint supply pipe 24
By operating a spray nozzle (not shown) attached to the tip of the, a paint is applied to the polished surface to form a new coating film.

At this time, since the expansion plug 15 is inserted into each downcomer 12 and the opening at the connection end of the vent pipe 14 on the side of the containment vessel body 2 is covered with the closing cover 16, it is caused by the polishing and painting work. Dust and the like are not scattered to the suppression chamber 6 and the dry well of the containment vessel 4 but are captured by the dust collector 21 via the dust suction pipe 22.

When the transfer of the water 5 from the suppression chamber 6 to the outside is completed, in parallel with the above-mentioned blasting work on the inner surface of the vent header 11 and the inner surface of the vent pipe 14, the manhole 9 moves the inside of the suppression chamber 6. A scaffold assembling work is carried out in which materials for scaffolding are carried in and work scaffolds are erected.

Next, existing coating films formed on the inner surface of the suppression chamber 6, the outer surface of the vent header 11, the inner surface and the outer surface of the downcomer 12, and the outer surface of the portion of the vent pipe 14 located in the suppression chamber 6 are sandblasted. , And a scaffold removal operation of disassembling the work scaffold and carrying out the scaffold material from the manhole 9 in order.

At the appropriate time, the expansion plug 1
5 and the closing cover 16 are collected.

After a curing period until the newly formed coating film is cured, the water 5 is returned into the suppression chamber 6.

As described above, in the above-described working process, the blasting work on the inner surface of the vent header 11 and the inner surface of the vent pipe 14 which is not usually immersed in the water 5 is performed by the water 5 from the suppression chamber 6 to the outside. It is possible to carry out the process required for repainting the suppression chamber 6 because the construction is performed during the transfer of the suppression chamber 6.

In addition, the sandblasting operation for the inner surface of the vent header 11 and the inner surface of the vent pipe 14 and the polishing operation for the other parts such as the inner surface of the suppression chamber 6 are not congested. Vessel 1
The number of spray coaters 7 and spray coaters 23 can be reduced, and the maximum power consumption in each of the spray coating works can be reduced.

The downcomer 12 and the vent header 11
Is closed by the expansion plug 15, and the connection between the vent pipe 14 and the dry well of the reactor containment vessel 4 is closed by the closing cover 16, so that dust and the like generated during the blast cleaning operation are suppressed. Chamber 6
And scattering to the dry well of the containment vessel 4 can be prevented.

The method of repainting the suppression chamber of the present invention is not limited to the above-described embodiment, and the inner surface of the vent header 11 and the vent pipe before the transfer of the water 5 from the suppression chamber 6 to the outside. 14 to perform an abrasive coating operation on the inner surface of the inner cover 14, to use the same means as the closing cover 16 for closing the connecting portion between the downcomer 12 and the vent header 11, It is needless to say that a structure having the same structure as that of the expansion plug 15 is used for the closing means of the connecting portion, and other changes can be made without departing from the gist of the present invention.

[0033]

As described above, according to the suppression chamber repainting method of the present invention, various excellent effects as described below can be obtained.

(1) Claim 1 or Claim 2 of the present invention
In any of the suppression chamber repainting method described in the above, usually, the blasting work on the inner surface of the vent header and the inner surface of the vent pipe that does not submerge in water, before the transfer of water from the suppression chamber to the outside, or Since the process required for repainting the suppression chamber is carried out during transfer, the period for periodic inspections can be shortened.
It is possible to improve the operation efficiency of the reactor facility.

(2) Since the sanding work for the inner surface of the vent header and the inner surface of the vent pipe and the sanding work for the other parts such as the inner surface of the suppression chamber are not congested, the sand blast sander and the sprayer are used. The number of coaters can be reduced, so that the maximum power consumption in each of the blasting and painting works can be reduced.

(3) In the method of repainting the suppression chamber according to the second aspect of the present invention, the connection between the downcomer and the vent header is closed, and the connection between the vent pipe and the dry well of the containment vessel is closed. Because of the blockage, it is possible to prevent dust and the like generated during the polishing coating operation from scattering to the suppression chamber and the dry well of the containment vessel.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of an embodiment of a suppression chamber repainting method of the present invention.

FIG. 2 is a comparison diagram showing a repainting process to which the present invention is applied and a conventional repainting process.

FIG. 3 is a conceptual diagram showing an example of a nuclear reactor facility.

[Explanation of symbols]

 4 Reactor containment vessel 5 Water 6 Suppression chamber 11 Vent header 12 Downcomer 14 Vent pipe

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Keimaru Niizawa 5-4-1-14 Tsukiji, Chuo-ku, Tokyo Sumitomo Tsukiji Building Ishikawajima Plant Construction Co., Ltd.

Claims (2)

[Claims] 1. Prior to or during the transfer of water from the suppression chamber to the outside, existing coating on the inner surface of the vent header disposed in the suppression chamber and the inner surface of the vent pipe communicating with the vent header. After the film has been removed by polishing, the paint is applied to the surface to be cleaned to form a new coating, and after the transfer of water from the suppression chamber to the outside is completed, the inner surface of the suppression chamber, the outer surface of the vent header, After removing the existing coating on the inner and outer surfaces of the downcomer and the outer surface of the portion located in the suppression chamber of the vent pipe, apply a paint to the polished surface to form a new coating. Characteristic suppression chamber repainting method. 2. A downcomer having a lower end submerged in water in the suppression chamber and a vent header disposed in the suppression chamber before or during the transfer of water from the suppression chamber to the outside. The existing coating film on the inner surface of the vent header and the inner surface of the vent pipe is ground while the connecting part of the vent header and the connecting part between the vent pipe communicating with the vent header and the dry well of the reactor pressure vessel are closed. After removal, apply a paint to the surface to be cleaned to form a new coating, and after the transfer of water from the suppression chamber to the outside is completed, the inner surface of the suppression chamber, the outer surface of the vent header, and the inner surface of the downcomer The existing coating on the outer surface and the outer surface of the portion of the vent pipe located in the suppression chamber is removed by polishing, and then the coated surface is coated. A method for repainting a suppression chamber, characterized in that a paint is applied to form a new paint film.