JP2000314794A - Suppression chamber dust collection and dehumidification method and apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the humidity in a suppression chamber while suppressing the diffusion of dust to the outside. SOLUTION: The air in the suppression chamber 6 is
A circulating air supply path is formed so as to be supplied into the suppression chamber 6 through the temporary duct 18, the filter 15 and the fan 16 of the dust collector 17, the air supply pipe 19, the dehumidifier 20, and the temporary duct 21, and the cleaning operation is performed. Dust generated at the time is captured by a filter 15 outside the suppression chamber 6, and moisture contained in air in the suppression chamber 6 is removed by a dehumidifier 20 outside the suppression chamber 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for collecting and dehumidifying a suppression chamber used for repainting.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a nuclear reactor, and FIG.
FIG. 1 shows an example of a conventional dust collecting means at the time of a suppression chamber cleaning operation. 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 containment vessel. A reactor containment vessel 4 comprising an upper lid 3 for closing the opening of the main body 2 and containing the reactor pressure vessel 1, and a lower part of the reactor containment vessel 4 circumferentially surrounding and storing water 5 therein; And a torus-shaped suppression chamber 6.

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, the suppression chamber 6 is used.
Draining work for transferring the water 5 inside to the outside, scaffolding assembling work for carrying scaffolding materials into the suppression chamber 6 from the manhole 9 and erection of the work scaffolding, the inner surface of the suppression chamber 6, the inner surface and the outer surface of the vent header 11 The existing coating films formed on the inner surface and outer surface of the downcomer 12, the inner surface of the vent pipe 14, and the outer surface of the portion of the vent pipe 14 located in the suppression chamber 6 are respectively peeled off by sandblasting and sprayed with a new paint. The scouring work for forming a film and the scaffold removal work for dismantling the work scaffold and carrying out the scaffolding material from the manhole 9 are sequentially performed.

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

At the time of performing the abrasive coating operation, the downstream end of the temporary duct 18 in the air flow direction is connected to the suction port of the dust collector 17 which is provided outside the suppression chamber 6 and has the filter 15 and the fan 16. In addition, a portion of the temporary duct 18 near the upstream end in the air flow direction is inserted from the manhole 9 into the suppression chamber 6, and
Activate

As a result, dust and the like generated due to the peeling of the coating film are captured by the filter 15, and the visibility of the worker in the suppression chamber 6 is secured.

[0012]

However, in the conventional blast coating operation, the humidity control in the suppression chamber 6 is not taken into consideration, and therefore, the polished surface from which the coating film has been peeled off must be coated as soon as possible. To avoid rusting on the polished surface.

It is also conceivable that a dehumidifier is provided outside the suppression chamber 6 and the air from which moisture has been removed by the dehumidifier is supplied into the suppression chamber 6 by a fan. When the air is forcibly supplied, the internal pressure of the suppression chamber 6 becomes higher than the atmospheric pressure, and there is a concern that radioactive dust and the like diffuse from the suppression chamber 6 to the outside.

The present invention has been made in view of the above circumstances, and has as its object to reduce the humidity in the suppression chamber while suppressing the diffusion of dust to the outside.

[0015]

According to a first aspect of the present invention, there is provided a method for collecting and dehumidifying a suppression chamber according to the present invention, wherein the inside of the suppression chamber and the dry well of the suppression chamber and the reactor containment vessel are provided. When cleaning the inside of the vent pipe that communicates with the air, the air in the suppression chamber and the vent pipe is sucked to capture dust accompanying the air, and the air after dust removal is dehumidified into the suppression chamber. Send.

According to a second aspect of the present invention, there is provided a dust collecting and dehumidifying method for a suppression chamber according to the first aspect of the present invention.
When the inside of the suppression chamber and the inside of the vent pipe communicating the suppression chamber with the dry well of the reactor containment vessel are cleaned, the communication of the vent pipe with the dry well of the reactor pressure vessel is cut off.

According to a third aspect of the present invention, there is provided a dust collecting and dehumidifying device for a suction chamber, which sucks air from the inside of the suppression chamber and the inside of the vent pipe and captures dust accompanying the air. It has a dehumidifier capable of dehumidifying the air sent from the dust collector, and an air flow path for feeding the air sent from the dehumidifier into the suppression chamber and the vent pipe.

According to a fourth aspect of the present invention, there is provided a dust collecting and dehumidifying apparatus according to the third aspect of the present invention.
A closing member is provided that can shut off communication between the inside of the suppression chamber and the dry well of the containment vessel.

In any one of the first and second aspects of the present invention, air is circulated between the inside and the outside of the suppression chamber to reduce dust and suppression generated during the cleaning operation. Moisture contained in the air in the chamber is transferred to the outside of the suppression chamber to secure a visual field in the suppression chamber and reduce the humidity, and to control the negative pressure inside the suppression chamber.

In the dust collecting and dehumidifying method according to the second aspect of the present invention, the communication between the inside of the suppression chamber and the dry well of the containment vessel is cut off, and the dust generated during the cleaning operation is removed from the containment vessel. Deters flying inside.

In any of the suppression chamber dust collecting and dehumidifying devices according to the third and fourth aspects of the present invention, the air in the suppression chamber is circulated through the dust collector and the dehumidifier into the suppression chamber. ,
The dust generated during the cleaning operation and the water contained in the air in the suppression chamber are transferred to the outside of the suppression chamber to secure a visual field in the suppression chamber and reduce the humidity, and to control the negative pressure in the suppression chamber.

[0022] In the suppression chamber dust collecting and dehumidifying device according to the fourth aspect of the present invention, the closing member is provided with a closing member.
The communication between the suppression chamber and the dry well of the containment vessel is cut off, so that dust generated during the cleaning operation is prevented from scattering into the containment vessel.

[0023]

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

FIG. 1 shows an example of an embodiment of a suppression chamber dust collecting and dehumidifying apparatus according to the present invention. In the drawing, the portions denoted by the same reference numerals as in FIGS. 2 and 3 represent the same components.

This suppression chamber dust collecting and dehumidifying device comprises a dust collector 17 having a filter 15 and a fan 16.
A temporary duct 18 whose downstream end in the air flow direction is connected to a suction port of the dust collector 17, a dehumidifier 20 whose intake port is connected to a discharge port of the dust collector 17 via an air supply pipe 19, A temporary duct 21 is connected to the discharge port of the dehumidifier 20 at the upstream end in the air flow direction.

When collecting and dehumidifying the inside of the suppression chamber 6, the closing cover 2 capable of covering the connection end opening portion of the vent pipe 14 on the side of the storage container body 2.
2 is used.

The operation of the suppression chamber dust collecting and dehumidifying apparatus shown in FIG. 1 will be described below.

After the draining operation for transferring the water 5 in the suppression chamber 6 to the outside and the scaffolding assembling work for transporting the scaffolding material from the manhole 9 into the suppression chamber 6 and erection of the working scaffold are completed, the polishing is performed. When performing the painting work, remove the piping (not shown) of the supply / exhaust system from the nozzle 10 to the suppression chamber 6,
The valve 13 is opened.

Next, the dust collector 17 and the dehumidifier 20 are arranged outside the suppression chamber 6, and both the discharge port of the dust collector 17 and the suction port of the dehumidifier 20 are communicated by the air supply pipe 19.

The downstream end of the temporary duct 18 in the air flow direction is connected to the suction port of the dust collector 17, and the portion of the temporary duct 18 near the upstream end in the air flow direction is inserted from the manhole 9 into the suppression chamber 6.

Further, the upstream end of the temporary duct 21 in the air flow direction is connected to the discharge port of the dehumidifier 20, and a portion of the temporary duct 21 near the downstream end in the air flow direction is inserted from the nozzle 10 into the suppression chamber 6.

In addition, the connection cover opening of each vent pipe 14 on the side of the containment vessel 2 is covered with a closing cover 22.

After operating the fan 16 in this state,
The inner surface of the suppression chamber 6, the inner and outer surfaces of the vent header 11, the inner and outer surfaces of the downcomer 12, the vent pipe 1
When the existing coating films formed on the inner surface of the suppression pipe 4 and the outer surface of the portion of the vent pipe 14 located in the suppression chamber 6 are peeled off by sandblasting, the air in the suppression chamber 6 is collected through the temporary duct 18. The air in the vent pipe 14 flows into the dust collector 17 through the vent header 11, the downcomer 12 or the body of the open valve 13, the suppression chamber 6, and the temporary duct 18, The dust generated by the peeling of the coating film is captured by the filter 15 of the dust collector 17.

The air sent from the fan 16 of the dust collector 17 flows into the dehumidifier 20 through the air supply pipe 19,
The dehumidifier 20 removes moisture contained in the air.

This air is fed into the suppression chamber 6 through the temporary duct 21 and further into the vent pipe 14 through the downcomer 12 or the body of the valve 13 that is open and the vent header 11. Therefore, the humidity inside the suppression chamber 6 and the inside of the vent pipe 14 are reduced.

After the existing coating film such as the inner surface of the suppression chamber 6 has been removed in this way, a new coating film is formed by spraying a paint on the polished surface.

Further, the work scaffold is dismantled, scaffold removal work for carrying out the scaffold material from the manhole 9 is carried out, the above-mentioned closing cover 22 is recovered, and curing until the newly formed coating film is cured. After a period, the water 5 is returned into the suppression chamber 6.

As described above, in the suppression chamber dust collecting and dehumidifying apparatus shown in FIG. 1, dust generated during the cleaning operation is captured by the filter 15, and in addition to securing a visual field in the suppression chamber 6 and the vent pipe 14, etc. The moisture contained in the air after dust removal is removed by the dehumidifier 20.
, And is fed into the suppression chamber 6 and the vent pipe 14, so that rusting on the inner surface of the suppression chamber 6 before spraying the paint can be effectively suppressed.

Also, during the cleaning operation, the connection end opening of the vent pipe 14 on the side of the containment vessel main body 2 is covered with the closing cover 22, so that scattering of dust to the dry well of the containment vessel 4 can be suppressed. Can be.

Further, the air in the suppression chamber 6 and the vent pipe 14 is supplied to the temporary duct 18, the filter 15 of the dust collector 17, the fan 16, the air supply pipe 19, the dehumidifier 20,
Since the circulation air supply path is formed so as to be supplied into the suppression chamber 6 and the vent pipe 14 through the temporary duct 21, the internal pressure of the suppression chamber 6 is increased due to the flow path resistance of the circulation air supply system and the like. The pressure is lower than the atmospheric pressure, so that the diffusion of dust to the outside of the suppression chamber 6 can be suppressed.

The method and the apparatus for collecting and dehumidifying the suppression chamber of the present invention are not limited to the above-described embodiment, but may be modified without departing from the scope of the present invention.

[0042]

As described above, according to the method and the apparatus for collecting and dehumidifying the suppression chamber of the present invention, the following various excellent effects can be obtained.

(1) Claim 1 or Claim 2 of the present invention
In any of the suppression chamber dust collection and dehumidification methods described in the above paragraph, air is circulated between the inside and the outside of the suppression chamber, so that dust generated during the cleaning operation and moisture contained in the air in the suppression chamber and the vent pipe are removed. Is transferred to the outside of the suppression chamber to secure the visual field in the suppression chamber and the vent pipe and reduce the humidity.
In addition, the diffusion of dust from inside the suppression chamber to the outside can be effectively suppressed.

(2) In the dust collecting and dehumidifying method of the suppression chamber according to the second aspect of the present invention, the communication between the inside of the suppression chamber and the dry well of the containment vessel is cut off. Dust scattering can be suppressed.

(3) Claim 3 or Claim 4 of the present invention
In any of the suppression chamber dust collecting and dehumidifying devices described in (1), the air in the suppression chamber and the vent pipe is circulated through the dust collector and the dehumidifier into the suppression chamber, and the dust generated during the cleaning operation and the suppression chamber are removed. Moisture contained in the air inside the vent pipe and inside the vent pipe is transferred to the outside of the suppression chamber to secure the visual field inside the suppression chamber and the vent pipe and reduce the humidity. Rust,
In addition, the diffusion of dust from inside the suppression chamber to the outside can be effectively suppressed.

(4) In the suppression chamber dust collecting and dehumidifying device according to the fourth aspect of the present invention, since the communication between the inside of the suppression chamber and the dry well of the reactor containment vessel is cut off by the closing member, the containment of the reactor is prevented. Dust scattering into the container can be suppressed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of an embodiment of a suppression chamber dust collecting and dehumidifying device of the present invention.

FIG. 2 is a conceptual diagram showing an example of a nuclear reactor facility.

FIG. 3 is a conceptual diagram showing an example of a conventional dust collecting means at the time of suppression chamber polishing.

[Explanation of symbols]

 Reference Signs List 4 Reactor containment vessel 6 Suppression chamber 14 Vent pipe 15 Filter 17 Dust collector 20 Dehumidifier 21 Temporary duct (air flow path) 22 Closing cover (closing member)

 ────────────────────────────────────────────────── ─── 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 (4)

[Claims] When cleaning the inside of a suppression chamber and the inside of a vent pipe that communicates the suppression chamber with a dry well of a reactor containment vessel, the air in the suppression chamber and the vent pipe is sucked to clean the inside of the suppression chamber. A method of collecting and dehumidifying a suppression chamber, comprising: capturing dust accompanying air, dehumidifying the air after removing the dust, and feeding the dehumidified air into a suppression chamber. 2. When the inside of the suppression chamber and the inside of the vent pipe communicating the suppression chamber with the dry well of the reactor containment vessel are cleaned, the vent pipe communicates with the dry well of the reactor pressure vessel. The method for collecting and dehumidifying a suppression chamber according to claim 1, wherein the dust is cut off. 3. A dust collector capable of sucking air from inside a suppression chamber and a vent pipe and capturing dust accompanying the air, a dehumidifier capable of dehumidifying air sent from the dust collector, A suppression chamber dust collecting and dehumidifying device, comprising: an air passage for supplying air sent from a dehumidifier into a suppression chamber and a vent pipe. 4. The suppression chamber dust collecting and dehumidifying apparatus according to claim 3, further comprising a closing member capable of blocking communication between the inside of the suppression chamber and the dry well of the containment vessel.