JPH09288191A - Reactor bellows installation method - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a novel method for installing a bellows for a nuclear reactor, which is capable of significantly saving labor for installing a bellows, which requires a lot of labor. In order to solve the above problems, the present invention is directed to a space between a top of a reactor pressure vessel 3 and a containment vessel 1 housed in a containment vessel 1 of a reactor building 12, and between the containment vessel 1 and a building 12. In the well seal bellows installation method for sealing the ring-shaped gaps respectively formed in the above, the bellows 18 formed in advance in a ring shape are divided into a plurality of divided bellows 19a ... These divided bellows 19a ... Are individually carried into the upper part of the storage container 1 in the building 12, and then integrally joined in a ring shape here, and then installed in the above gap.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor bellows installation method for sealing a ring-shaped gap formed between the top of a reactor pressure vessel and a containment vessel.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional steel containment vessel (P
CV) is shown. As shown in the figure, the steel containment vessel 1 is made by connecting steel plates in a substantially bell shape to improve pressure resistance, and has a pedestal 2 inside.
A reactor pressure vessel (RPV) 3 standing upright is accommodated, and an upper dry well 5, a lower dry well 6, a suppression chamber 7 and a living body shielding wall 8, which are partitioned by a pedestal 2 and a diaphragm floor 4, a vent. A tube 9 and the like are formed and housed. Further, a top lid 10 that can be opened and closed is provided on the top of the storage container 1, and by opening and closing the top lid 10, the upper mirror 11 of the pressure vessel 3 can be opened for fuel exchange.

A concrete building 12 is provided around the storage container 1 at a predetermined interval so as to surround the storage container 1.
Is provided to shield radiation from the side of the storage container 1 and to be provided with necessary equipment and piping system. Further, on the ceiling of the building 12, a pool 13 for temporarily storing spent fuel and the like when the fuel of the pressure vessel 3 is exchanged, an overhead crane 14 for exchanging the fuel, a roof portion 15 and the like are formed. ing.

Well seal mechanisms 16 are provided between the pressure vessel 3 and the containment vessel 1 and between the containment vessel 1 and the concrete building 12, respectively. Pressure vessel 3 when filled with water
These gaps are sealed to prevent water from leaking between the storage container 1 and the storage container 1 and between the storage container 1 and the concrete building 12. In addition, this well seal mechanism 1
As shown in FIG. 2, two ring-shaped bellows 18a and 18b, which are bellows-shaped in the height direction, are provided in the column 6, and the bellows 18a and 18b expand and contract to deform the concrete building 12. Displacement due to thermal deformation of the steel containment vessel 1 and the pressure vessel 3 is allowed to always ensure good sealability.

[0005]

By the way, the bellows 18a, 18 forming a part of the well seal mechanism 16 are provided.
Since b is formed by bending the SUS thin strip steel into a circular shape and joining them in a ring shape as described above, and then performing bellows molding, as shown in FIG. It can be installed from above the opening 17 of the storage container 1 by a crane or the like not shown. However, when the sealing property gradually deteriorates due to aging deterioration and it becomes necessary to replace it,
The overhead crane 14 and the building 1
Since the second ceiling portion 15 and the like are constructed, in order to use such a construction method at the time of construction, the ceiling crane 14 and the like already installed are removed and the ceiling portion 15 of the building 12 is also removed.
To the extent that the ring-shaped bellows 18 can pass through (for example,
It is necessary to form an opening having a diameter of about 10 m), and there is a problem that the installation work requires a lot of labor and time.

Therefore, the present invention has been devised in order to effectively solve such a problem, and the purpose thereof is to newly install a bellows, which requires a great deal of labor, and can greatly save labor. It provides a method for installing bellows for a nuclear reactor.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a reactor pressure vessel housed in a containment vessel of a reactor building, between the top and the containment vessel, and between the containment vessel and the building. In the well seal bellows installation method for sealing the ring-shaped gaps formed respectively, the ring-shaped bellows are divided into a plurality of divided bellows along the circumferential direction, and these divided bellows are formed. After being individually carried into the upper part of the storage container in the building, they are integrally joined here in a ring shape, and then they are installed in the above-mentioned gap.

As a result, it is not necessary to remove the overhead crane or the like above the pressure vessel or to form a large opening in the ceiling of the building when carrying the split bellows into the building, which saves labor for installing the bellows. Can be achieved. Even when the old bellows that has already been attached is removed, it can be easily carried out after removal by dividing it into a plurality of parts by melting or the like.

[0009]

Next, a preferred embodiment of the present invention will be described.

FIG. 2 shows the well seal mechanism 16 shown in FIG.
Fig. 12 is an enlarged cross-sectional view showing the above-mentioned concrete building, 1 is a steel containment vessel, and 3 is the vicinity of the top of each reactor pressure vessel.

As shown, this well seal mechanism 1
Reference numeral 6 denotes an expandable ring-shaped fuel exchange bellows between a platform 20 projecting from the containment vessel 1 to the reactor pressure vessel 3 side and a basin seal 21 projecting from the reactor pressure vessel 3 to the containment vessel 1 side. 18a is bridged up and down, and a ring-like expandable ring is also provided between a platform 22 projecting from the reactor containment vessel 1 to the concrete building 12 side and a building side platform 23 projecting from the concrete building 12 to the containment vessel 1 side. The well-sealed bellows 18b having the above-mentioned structure is bridged vertically. Then, the reactor pressure vessel 3 accompanying the thermal expansion and contraction
Of the relative displacement between the reactor containment vessel 1 and the fuel exchange bellows 1
By absorbing the relative displacement between the reactor containment vessel 1 and the concrete building 12 due to the thermal expansion and contraction on the well seal bellows 18b side as well as absorbing it on the 8a side, the concrete building 12 is maintained while maintaining good sealing performance. Thermal displacement of the reactor containment vessel 1 and the reactor pressure vessel 3 is allowed. In the figure, 24 and 25 are drain pipes for draining pool water stretched over the upper part of the well seal mechanism 16, 10 is a removable upper lid at the upper opening of the reactor containment vessel 1, and 26 and 27 are fuel. The seal plate is vertically slidable in order to reduce the water pressure applied to the exchange bellows 18a and the well seal bellows 18b.

Next, an embodiment of a method of installing the well seal bellows 18b, which constitutes a main part of the well seal mechanism 16, will be described.

First, as shown in FIG. 1 (A), a well seal bellows 18 formed in a ring shape in advance at a factory or the like.
Split bellows 19a, 19a, 19a, 19a are formed by dividing b into a plurality of, for example, four along the circumferential direction, and these split bellows 19a, 19a, 19a,
19a is carried in on the operating floor 26 above the storage container 1 in the concrete building 12 shown in FIG. The size of the split bellows 19a is several m to 10 m in length,
Since it is small and lightweight with a width of several tens of centimeters and a weight of several kilograms, it is extremely easy to carry it in by using the existing carry-in holes 27 and the like formed in the building 12 on the side of the operating floor 26. be able to. Further, since these divided bellows 19a, 19a, 19a, 19a are made of a thin metal plate and are easily deformed, as shown in FIG. 2 (A), the deformation preventing jig 28 for holding the shape thereof is used.
It is preferable to prevent the deformation by such means.

Next, such divided bellows 19a, 1
When the loading of 9a, 19a, 19a onto the operating floor 26 is completed, the operating floor 2
As shown in FIG. 1 (B), the split bellows 19a, 19a, 19a, 19a are arranged in a ring shape by using 6,
The ends are butt-welded and integrally joined in a ring shape. In this case, when joining the divided bellows 19a to each other by superposition and welding, it goes without saying that the end portions of the divided bellows 19a are formed long only for the overlapping portions.

After that, if such a ring-shaped well seal bellows 18b is formed, the well seal bellows 18b is hung on the overhead crane 14 as shown in FIG. It will be installed on the well seal mechanism 16 between the storage container 1 and the building 12 after being positioned on the opening 17 and lowered. During this installation work, the old well seal bellows 18b
Needless to say, is removed from the well seal 16 in advance by fusing and dividing.

The fuel exchange bellows 18a of the well seal mechanism 16 between the pressure vessel 3 and the storage vessel 1 is also installed by the same work.

As described above, according to the method of the present invention, since the large ring-shaped bellows is formed in advance by the plurality of divided blocks, it is possible to carry out the work into the building extremely easily. Therefore, when installing the bellows, it is not necessary to remove the existing equipment such as an overhead crane at the upper part of the building or to form a large opening in the ceiling of the building, and the labor required for the installation work can be significantly reduced. It should be noted that although the present embodiment has been described using four divided blocks, the present invention is not limited to this embodiment, and the present invention is not limited to this, and it may be divided into a plurality of two or three or five or more. Of course, it is okay. Then, by dividing into two or three in this way, the assembling work in the building is further labor-saving, and conversely
If it is divided into a plurality of pieces, the carrying-in work becomes easier.

[0018]

In summary, according to the present invention, by forming a large bellows into a plurality of divided blocks in advance, it is possible to extremely easily carry the work into the building. At the time of installation work, it is not necessary to remove existing equipment such as an overhead crane at the top of the building or to form a large opening in the building ceiling, and the labor required for the installation work can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a process drawing showing an embodiment of a method of the present invention.

FIG. 2 is a partially enlarged vertical sectional view showing a well seal mechanism according to the method of the present invention.

FIG. 3 is a vertical cross-sectional view showing a conventional steel containment vessel (PCV) and its building.

[Explanation of symbols]

 1 Reactor containment vessel 3 Reactor pressure vessel 14 Ceiling crane 16 Well seal mechanism 18 Bellows 18b Well seal bellows 19a Divided bellows

Claims (1)

[Claims] 1. A well seal for sealing ring-shaped gaps formed between the top and the containment vessel of the reactor pressure vessel housed in the containment vessel of the reactor building and between the containment vessel and the building. In the bellows installation method of, in order to form a divided bellows divided into a plurality of ring-shaped bellows along the circumferential direction in advance, after carrying these divided bellows individually into the upper part of the containment vessel in the building,
Here, the bellows installation method for a nuclear reactor is characterized in that it is integrally joined in a ring shape and then installed in the above-mentioned gap.