JP2005300447A - Installation method of bellows - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an installation method of bellows for a nuclear reactor capable of significantly saving the labor of installation work of bellows which requires a lot of labor. <P>SOLUTION: This installation method of bellows for sealing ring-like spaces formed between the top part of a reactor pressure vessel stored in a containment vessel of a reactor building 30 and the containment vessel and between the containment vessel and the reactor building 30 comprises a process for cutting a bellows material plate in a predetermined dimension and carrying it to an upper part of the containment vessel in a rolled state; a process for setting up the bellows material plate 1 in a cylindrical shape; and a process for performing corrugated molding work to the bellows material plate 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reactor bellows installation method for sealing a ring-shaped gap formed between the top of a reactor pressure vessel and a containment vessel.

At the bottom of the reactor well in the conventional boiling water reactor building, the gap between the trunk flange of the reactor pressure vessel (RPV) and the bulkhead plate inside the top flange portion of the reactor containment vessel (PCV) is the basin seal. Sealed with refueling bellows and bulkhead seal plate. Further, the gap between the outside of the PCV top flange portion and the reactor well stage is sealed by the PCV seal plate and the reactor well seal bellows. The refueling bellows and the reactor well seal bellows are each a combination of expansion joints molded into corrugated stainless steel with a thickness of about 2 mm each to absorb longitudinal displacement and lateral displacement during operation and fuel The reactor well can be filled at the time of replacement.
However, since the fuel exchange bellows and the reactor well seal bellows are as large as about 6 to 11 m in diameter, it is impossible to carry them in from the entrance of the reactor building, and establishment of replacement technology is an issue.
For this reason, as shown in Patent Document 1, a fuel exchange bellows or a reactor well seal bellows is formed in a ring shape in advance and divided into a plurality of pieces along the circumferential direction, and these divided bellows are carried onto the operation floor from the carry-in entrance. After that, a method has been proposed in which the ring is integrally joined and installed.
Japanese Patent Laid-Open No. 9-288191

However, the above-described method requires welding and nondestructive inspection of the expansion joint formed into a corrugated shape, and it is difficult to obtain a high-quality weld. Furthermore, since equipment such as a containment vessel top head and a reactor pressure vessel top lid may be placed on the operation floor of the reactor building, there is a problem that a working space necessary for assembling the bellows cannot be secured.
On the other hand, a method in which the ceiling of the reactor building is completely removed and the reactor well seal bellows and the fuel exchange bellows are carried in as one body is not feasible from the viewpoint of preventing the diffusion of radioactive materials. Moreover, the method of providing an opening in the side wall of the ceiling or the operation floor and carrying in the reactor well seal bellows and the fuel change bellows integrally with a large crane, respectively, requires an air lock to maintain the airtightness of the building. There is a problem that it is not realistic because it occurs or the construction work around the plant becomes necessary and the plant shutdown period becomes longer.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a method for installing a bellows for a reactor that can greatly save labor for installing a bellows that requires a great amount of labor.

The bellows installation method according to the present invention employs the following means in order to solve the above problems.
The present invention provides ring-shaped gaps formed between the top of the reactor pressure vessel housed in the containment vessel of the reactor building and the containment vessel, and between the containment vessel and the reactor building, respectively. In the installation method of the bellows to be sealed, the step of cutting the bellows base plate into a predetermined size and winding it into the upper part of the storage container, the step of assembling the bellows base plate into a cylindrical shape, and the corrugated molding to the bellows base plate And a step of applying processing. According to this invention, since a ring-shaped bellows can be assembled in the reactor building, there is no need to disassemble the bellows and carry it in from the reactor building entrance or to provide a special entrance. .

  Further, ring-shaped gaps formed between the top of the reactor pressure vessel accommodated in the containment vessel of the reactor building and the containment vessel, and between the containment vessel and the reactor building, respectively. In the installation method of the bellows to be sealed, a step of assembling the bellows base plate into a cylindrical shape, a step of elastically deforming the cylindrical bellows base plate and carrying it into the upper part of the containment vessel, and a step of corrugating the bellows base plate , To have. According to the present invention, the ring-shaped bellows is carried into the reactor building in an easily deformable state (before the wave forming process), so that the bellows can be disassembled and carried from the reactor building entrance, or a special carry-in. There is no need to provide a mouth.

In addition, in the waveform forming process, if the bellows base plate assembled in a cylindrical shape is subjected to the waveform forming process in a state where the cylindrical axis direction is substantially horizontal, the bellows waveform forming process can be performed satisfactorily. it can.
Further, if the wave forming process is performed during operation of the nuclear reactor plant, the replacement work can be performed immediately.
In addition, when lifting an existing fuel exchange bellows prior to installation of the bellows, if a restraint is attached between the lower portion of the backing plate cover and the backing plate, the bellows will be prevented from being extended to facilitate lifting. be able to.
In addition, when the existing reactor well seal bellows is lifted prior to the installation of the bellows, if a restraint is attached between the upper flange and the lower flange or between the upper flange and the lower end ring, Elongation can be prevented and lifting can be facilitated.
In addition, when lifting the existing reactor well seal bellows prior to installation of the bellows, a restraint is attached between the lower flange and the guard ring to prevent the bellows from extending and facilitate lifting. be able to.

According to the present invention, the following effects can be obtained.
The present invention provides ring-shaped gaps formed between the top of the reactor pressure vessel housed in the containment vessel of the reactor building and the containment vessel, and between the containment vessel and the reactor building, respectively. In the installation method of the bellows to be sealed, the bellows base plate is cut into a predetermined size, rolled into a container, and loaded into the upper part of the storage container, and then assembled into a cylindrical shape, and further subjected to corrugated forming processing on the bellows base plate. did. Alternatively, after assembling the bellows base plate into a cylindrical shape, the cylindrical bellows base plate is elastically deformed and carried into the upper part of the storage container, and thereafter, the bellows base plate is subjected to corrugated forming.
For this reason, since the bellows is not disassembled, the same required quality as that produced by the factory can be secured. Moreover, since it is not necessary to provide an opening in the ceiling of the reactor building or the side wall of the operation floor, the installation work and the restoration work for the opening are not required, and the plant shutdown period can be greatly shortened. Furthermore, since a new bellows can be assembled during plant operation, the preparation period for replacement can be shortened.

Hereinafter, an embodiment of a method for installing a bellows for a reactor according to the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a configuration of a reactor building 30 that is a part of a boiling water nuclear power plant (BWR plant).
The reactor building 30 is erected on the ground and includes a reactor containment vessel 34 (Primary Containment Vessel) therein.
The reactor containment vessel 34 is a building important for safety of the reactor, and houses the reactor pressure vessel 32 and structures such as cooling system facilities. Generally, it is made of light bulb-shaped or bell-shaped steel or reinforced concrete, and has an airtight and pressure-resistant structure. In the event of an accident such as a reactor accident or damage to the reactor cooling system, radioactive materials are released to the outside. It serves to prevent. In addition, in this embodiment, it forms in a light bulb shape.
The reactor pressure vessel 32 (reactor pressure vessel) is a vertical cylindrical shape with a hemispherical top and bottom, and is composed of a reactor vessel top lid and a reactor vessel body. The reactor pressure vessel 32 is installed on the pedestal and is fixed by a foundation bolt and is self-supporting. Note that the pedestal is a structure of concrete and a steel plate frame or a reinforcing bar because it serves as the foundation of the reactor pressure vessel 32.
A reactor shielding wall for shielding radiation from the reactor is provided outside the reactor pressure vessel 32. The reactor shielding wall is an iron plate frame concrete structure having a thickness of 600 to 700 mm.

  The upper part of the reactor containment vessel 34 is provided with shielding water that shields radiation from the fuel assembly or the like when a fuel assembly or a structure (not shown) in the reactor pressure vessel 32 is exchanged or taken out. A reactor well 31 is provided.

FIG. 2 is a plan layout view of the operation floor 50 of the reactor building 30.
The operation floor 50 in the reactor building 30 includes a spent fuel pool 58 for storing used fuel assemblies and an equipment pool 57 for storing in-reactor structures taken out of the reactor. They are arranged symmetrically across the reactor well 31. In addition, an equipment hatch 59 for carrying in equipment in communication with a carry-in entrance on the ground floor is provided.

FIG. 3 is an enlarged view of part A of FIG.
A gap between the trunk flange 33 of the reactor pressure vessel 32 and the bulkhead plate 36 inside the top flange portion 35 of the reactor containment vessel 34 is sealed with a basin seal 37, a fuel change bellows 38, and a bulkhead seal plate 39. . Further, the gap between the outside of the PCV top flange portion 35 and the reactor well stage 40 is sealed by the PCV seal plate 41 and the reactor well seal bellows 42.
A basin shield drain 43 and a PCV well seal drain 44 are installed at the bottom of both gaps. The bulkhead plate 36 is provided with a bulkhead drain 45 so that water in the reactor well 31 can be drained.
The fuel exchange bellows 38 has a secondary seal structure and a seal for drainage to prevent water leakage into the reactor containment vessel 34 to a minimum when a damage accident occurs in the bellows body 1 during fuel exchange. A destruction drain 46 is provided. The bulkhead web 47 and the backing plate cover 8 are reinforced with a bulkhead web lower reinforcing plate 48.
The reactor well seal bellows 42 has a drainage structure and a well on the reactor building 30 side in order to minimize water leakage into the reactor building when the bellows body 1 is damaged during fuel exchange. A seal breaking drain 49 is provided.

FIG. 4 is a diagram showing a detailed configuration of the fuel exchange bellows 38.
The fuel exchange bellows 38 is configured by sandwiching two bellows bodies 1 between a lower end ring 3, an intermediate end ring 4, and an upper end ring 5. Flange 6 is arranged on these upper parts. In addition, the spring seal 2, the backing plate 7, the backing plate cover 8, the backing plate support 9, and the spring seal dam 10 are disposed outside these. Furthermore, a guard ring 11, a guard ring abutting plate 12, a guard ring support 13, a hexagon bolt 14 and a spring washer 15 are arranged inside these. Further, the backing plate 7 is provided with a seal breaking drain nozzle 16.
When installing the fuel exchange bellows 38, if the fuel exchange bellows 38 is lifted, the bellows body 1 will be stretched by its own weight. To prevent this, the guard ring 11 and the guard ring support 13 are secured with bolts 20. Temporarily fixed. And the bolt 20 is removed after installation. Moreover, although the hanging bracket 24 is provided in the upper part, it is cut and removed after installation.

FIG. 5 is a detailed configuration diagram of the reactor well seal bellows 42.
The reactor well seal bellows 42 is configured by sandwiching the bellows body 1 between a lower end link 3 and an upper end ring 5. A lower flange 17 and an upper flange 18 are disposed above and below them. In addition, a guard ring 11, a guard ring abutting plate 12, a guard ring support 13, an upper guard ring support 19, a hexagon bolt 14, and a spring washer 15 are arranged inside these.
When the reactor well seal bellows 42 is installed, if the reactor well seal bellows 42 is lifted, the bellows body 1 is extended by its own weight. To prevent this, the guard ring 11 and the guard ring support 13 are provided. Is temporarily fixed with a bolt 20. And the bolt 20 is removed after installation. Moreover, although the hanging bracket 24 is provided in the upper part, it is cut and removed after installation.

Next, an installation (exchange) method for the fuel exchange bellows 38 and the reactor well seal bellows 42 will be described.
FIG. 6 is a diagram showing a manufacturing procedure of the fuel change bellows 38. The basic flow of this procedure is the same as when manufacturing at a factory, but the following technical measures are taken to optimize the manufacturing range at the site (operation floor 50 of the reactor building 30).
First, the bellows main body (bellows base plate) 1 is cut into a predetermined length at a factory and wound into a roll shape, and then carried into the operation floor 50 in the reactor building 30 and then welded with a vertical joint. To make it cylindrical.
Alternatively, the bellows base plate 1 is cut into a predetermined length at a factory, and a vertical joint is welded to form a cylindrical shape. Thereafter, the cylindrical bellows base plate 1 is elastically deformed into, for example, an ellipse or an ellipse, packaged and shipped, and carried into the operation floor 50 in the reactor building 30.
Which of the two methods described above is selected is determined by the size that can be carried in from the large material entrance of the reactor building 30 to the operation floor 50.
Subsequently, as shown in FIG. 7, the axial direction of the bellows base plate 1 assembled into a cylindrical shape is set to be substantially horizontal, and corrugated processing is performed using a roll molding machine 52. Since the bellows base plate 1 (cylindrical) before molding is small in rigidity and deforms into an elliptical shape or an oval shape with its own weight, a hanging tool 51 is provided on the roof truss 53 above the roll molding machine 52 installation place. Prevent abnormal deformation and smooth roll feeding. The roll forming machine 52 and the correction press machine are brought into the site.
Secondly, the flange 6, the upper end ring 5, and the spring seal dam 10 are economical to assemble by cutting out from the plate and bending or welding it in a plurality of divided shapes to improve the yield of the steel plate. The number depends on the size. Then, each is cut out, partially integrated, and assembled to a size that can be carried on-site. Then, the whole is temporarily assembled and checked. There is no problem even if the number of parts to be integrated is large, but it is desirable that the number is partially reduced from the viewpoint of minimizing the amount of on-site construction. It is carried on-site in a partially integrated shape unit and integrated on the operation floor 50.
Third, since the spring seal 2 is pressed, the number of divisions is large. Partially integrated at the factory and assembled to the size that can be carried on-site. After that, the whole is temporarily assembled and checked. There is no problem even if the number of parts to be integrated is large, but it is desirable that the number is partially reduced from the viewpoint of minimizing the amount of on-site construction. It is carried on-site in a partially integrated shape unit and integrated on the operation floor 50.
Fourth, the lower end ring 3 and the backing plate support 9 are assembled by a partial integration method.

The method for manufacturing the reactor well seal bellows 42 is the same as that for manufacturing at the factory, but the following technical measures are taken to optimize the manufacturing range at the site (operation floor 50 of the reactor building 30). .
First, the bellows main body (bellows base plate) 1 is cut into a predetermined length at a factory and wound into a roll shape, and then carried into the operation floor 50 in the reactor building 30 and then welded with a vertical joint. To make it cylindrical.
Alternatively, the bellows base plate 1 is cut into a predetermined length at a factory, and a vertical joint is welded to form a cylindrical shape. Thereafter, the cylindrical bellows base plate 1 is elastically deformed into, for example, an ellipse or an ellipse, packaged and shipped, and carried into the operation floor 50 in the reactor building 30.
Which of the two methods described above is selected is determined by the size that can be carried in from the large material entrance of the reactor building 30 to the operation floor 50.
Subsequently, as shown in FIG. 7, the axial direction of the bellows base plate 1 assembled into a cylindrical shape is set to be substantially horizontal, and corrugated processing is performed using a roll molding machine 52. Since the bellows base plate 1 (cylindrical) before molding is small in rigidity and deforms into an elliptical shape or an oval shape with its own weight, a hanging tool 51 is provided on the roof truss 53 above the roll molding machine 52 installation place. Prevent abnormal deformation and smooth roll feeding. The roll forming machine 52 and the correction press machine are brought into the site.
Secondly, the upper end ring 5 and the upper guard ring support 19, and the lower end ring 3 and the lower flange 17 are assembled by being cut out from the plate and bent or welded into a plurality of divided shapes in order to improve the yield of the steel plate. This is economical, and the number of divisions varies depending on the size. Then, each is cut out, partially integrated, and assembled to a size that can be carried on-site. After that, the whole is temporarily assembled and checked. There is no problem even if the number of parts to be integrated is large, but it is desirable that the number is partially reduced from the viewpoint of minimizing the amount of on-site construction. It is carried on-site in a partially integrated shape unit and integrated on the operation floor 50.
Thirdly, since the upper flange 18 is installed in the reactor well 31 after being installed with the reactor well stage 40, it is carried in a state of being divided into a plurality of parts.

  The assembly of the refueling bellows 38 and the reactor well seal bellows 42 on the operating floor 50 is desirable during operation of the reactor plant. After the assembly, it is temporarily placed with the axial direction horizontal on the wall at a position where the traveling of the overhead crane 54 does not hinder. The refueling bellows 38 and the reactor well seal bellows 42 have a large diameter but a low height. When the fuel replacement bellows 38 and the reactor well seal bellows 42 are replaced at the same time, the fuel replacement bellows 38 is placed inside the reactor well seal bellows 42, so that the temporary storage area can be reduced by storing them integrally. .

FIG. 8 is a view showing a method of removing the existing fuel change bellows 38.
At the time of installation, the guard ring 11 and the guard ring support 13 are fixed by the bolts 20 and the expansion and contraction of the bellows main body 1 is restricted, but the bolts 20 are removed after the installation. Therefore, there is no guarantee that the bolt 20 can be implanted again when the fuel change bellows 38 is removed. Moreover, since the gap between the basin seal 37 and the guard ring 11 is small, it is difficult to perform a new operation.
Therefore, a new restraining material 21 that restrains the expansion and contraction of the bellows body 1 is attached between the backing plate 7 and the backing plate cover 8. In addition, a plurality of hanging brackets 24 are attached to the upper surface of the flange 6.
The bulkhead seal plate 39 is cut at the position a, the bulkhead web lower reinforcing plate 48 at the position b, the seal breaking drain line 46 at the position c, and the lower end ring 3 at the position d.
The positions a and b are set so that the position a is located outside the position b between the bulkhead plate 36 and the backing plate cover 8. Further, the position c is cut at or near the seal breaking drain nozzle 16 so as not to interfere with the lifting.
Subsequently, the existing fuel exchange bellows 38 is lifted from the reactor well 31 onto the operation floor 50 by the overhead crane 54, and is chopped and stored in drums or casks. Then, the existing remaining portions of the bulkhead seal plate 39 and the lower end ring 3 are removed. The existing remaining portion of the bulkhead web lower reinforcing plate 48 may or may not be removed because the new reinforcing plate can be attached to the opposite side of the bulkhead web 47.

FIG. 9 is a diagram showing a method for installing the new fuel change bellows 38.
A new fuel change bellows 38 is suspended from the operation floor 50 into the reactor well 31 and installed at a predetermined position.
Then, the basin seal flange 55 and the lower end ring 3 are welded, and then the bulkhead seal plate 39 and the bulkhead web lower reinforcing plate 48 divided into a plurality of parts are attached.
Next, the seal breaking drain line 46 is restored, and the bolt 20 that has fixed the guard ring 11 and the guard ring support 13 is removed. The hanging bracket 24 is also removed.

FIG. 10 is a view showing a method of removing the existing reactor well seal bellows 42.
At the time of installation, the guard ring 11 and the guard ring support 13 are fixed by the bolts 20 and the expansion and contraction of the bellows main body 1 is restricted, but the bolts 20 are removed after the installation. Therefore, there is no guarantee that the bolt 20 can be implanted again when the reactor well seal bellows 42 is removed.
Therefore, a new restraining material 22 that restrains the expansion and contraction of the bellows body 1 is attached between the guard ring and the lower flange. The restraining material 23 may be provided between the upper flange 18 and the lower end ring 3 or the lower flange 17. Further, a plurality of hanging fittings 24 are attached to the upper end of the upper end ring 5.
And the upper flange 18 is cut | disconnected in the position e, and the welding part (position f) of the lower flange 17 and the PCV seal plate 41 is removed. The position e is larger than the outer diameter of the lower flange 17 so that the lower flange 17 does not interfere with the lifting.
Subsequently, the reactor well seal bellows 42 is lifted from the reactor well 31 onto the operation floor 50 by the overhead crane 54, and is chopped and stored in a drum can or a cask. Then, the existing remaining portion of the upper flange 18 is removed.

FIG. 11 is a diagram showing a method for installing the new reactor well seal bellows 42.
A new reactor well seal bellows 42 to which the upper flange 18 is not attached is suspended from the operation floor 50 into the reactor well 31 and installed at a predetermined position.
Then, the PCV seal plate 41 and the lower flange 17 are welded, and then the upper flange 18 divided into a plurality of parts is attached between the well chick step plate 56 and the upper end ring 5.
Next, the bolt 20 that has fixed the guard ring 11 and the guard ring support 13 is removed. The hanging bracket 24 is also removed.

As described above, according to the present invention, between the top of the reactor pressure vessel 32 accommodated in the containment vessel 34 of the reactor building 30 and the containment vessel 34 and between the containment vessel 34 and the reactor building 30. In the installation method of the bellows 38 and 42 for sealing the ring-shaped gaps formed respectively between the two, the bellows base plate 1 is cut into a predetermined size, wound into a roll shape, and carried into the upper portion of the storage container 34. It was assembled in a cylindrical shape, and the bellows base plate 1 was further subjected to wave forming. Alternatively, after assembling the bellows base plate 1 into a cylindrical shape, the cylindrical bellows base plate 1 is elastically deformed and carried into the upper portion of the storage container 34, and thereafter, the bellows base plate 1 is subjected to a wave forming process.
For this reason, since the bellows 38 and 42 are not disassembled, the same required quality as that produced by the factory can be secured. Moreover, since it is not necessary to provide an opening in the ceiling of the reactor building 30 or the side wall of the operation floor 50, installation work and restoration work for the opening are not required, and the plant shutdown period can be greatly shortened. Furthermore, since the new bellows 38 and 42 can be assembled during plant operation, the preparation period for replacement can be shortened.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

Longitudinal sectional view showing the configuration of the reactor building 30 Plan layout of the operation floor 50 of the reactor building 30 Part A enlarged view of FIG. The figure which shows the detailed structure of the fuel exchange bellows 38 The figure which shows the detailed structure of the reactor well seal bellows 42 The figure which shows the production procedure of the fuel change bellows 38 The figure which shows the support method at the time of molding of the bellows body The figure which shows the removal method of the existing fuel exchange bellows 38 The figure which shows the installation method of the new fuel change bellows 38 The figure which shows the removal method of the existing nuclear reactor well seal bellows 42 The figure which shows the installation method of the new reactor well seal bellows 42

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bellows main body, Bellows base plate 3 Lower end ring 7 Backing plate 8 Backing plate cover 11 Guard ring 17 Lower flange 18 Upper flange 21 Restraint material 22 Restraint material 23 Restraint material 30 Reactor building 32 Reactor pressure vessel 34 Reactor containment vessel 38 Fuel change bellows
42 Reactor well seal bellows (bellows)

Claims (7)

Sealing ring-shaped gaps formed between the top of the reactor pressure vessel accommodated in the containment vessel of the reactor building and the containment vessel, and between the containment vessel and the reactor building, respectively. In the bellows installation method,
A step of cutting the bellows base plate into a predetermined size and rolling it into the upper part of the containment vessel; and
Assembling the bellows base plate into a cylindrical shape;
A step of corrugating the bellows base plate;
A method for installing a bellows, comprising: Sealing ring-shaped gaps formed between the top of the reactor pressure vessel accommodated in the containment vessel of the reactor building and the containment vessel, and between the containment vessel and the reactor building, respectively. In the bellows installation method,
Assembling the bellows base plate into a cylindrical shape,
A step of elastically deforming the cylindrical bellows base plate and carrying it into the upper part of the containment vessel;
A step of corrugating the bellows base plate;
A method for installing a bellows, comprising:   3. The corrugated forming process according to claim 1, wherein the corrugated forming process is performed in a state where the bellows base plate assembled in a cylindrical shape is erected so that a cylindrical axis direction is substantially horizontal. How to install the bellows.   4. The bellows installation method according to any one of claims 1 to 3, wherein the corrugating process is performed during operation of a nuclear reactor plant.   5. When the existing fuel change bellows is lifted prior to the installation of the bellows, a restraint is attached between the lower portion of the backing plate cover and the backing plate to lift the bellows. The installation method of the bellows as described in a term.   When the existing reactor well seal bellows is lifted prior to the installation of the bellows, a restraining material is attached between the upper flange and the lower flange or between the upper flange and the lower end ring, and is lifted. The installation method of the bellows as described in any one of Claims 1-5. 6. When the existing reactor well seal bellows is lifted prior to the installation of the bellows, a restraint member is attached between the lower flange and the guard ring to lift the bellows. The installation method of the bellows as described in a term.

Images