JPH07218696A - Replace method for reeactor pressure vessel - Google Patents

Abstract

PURPOSE:To attain simplification of work and shortening of work period from removal to replacement of a pressure vessel. CONSTITUTION:In removing a pressure vessel 4 upward in the structure 1 for replacing the reactor pressure vessel 4 contained surrounded by reactor shield walls 3 in a containment 2 in a reactor building structure 1, pipes 8 connected to the pressure vessel 4 through the shield walls 3 are separated by cutting between the pressure vessel 4 and the shield walls, the fixing of the pressure vessel 4 placed on the basement 13 is released and the pressure vessel 4 is hung up to remove out of the containment 2 and the structure 1 opened upward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor pressure which can reduce the influence on the structure around the pressure vessel when the reactor pressure vessel is removed in order to replace the reactor pressure vessel with a new one. It relates to a new container replacement method.

[0002]

2. Description of the Related Art In a nuclear power plant or the like, a containment vessel is housed in a reactor building body, and a reactor pressure vessel surrounded by a shielding wall is installed in the containment vessel.

[0003]

By the way, the reactor is also decommissioned after a predetermined useful life. In the case of decommissioning, the most damaged reactor pressure vessel will be removed and replaced with a new pressure vessel, but when removing a used pressure vessel, leave the structure around the pressure vessel as it is. If
The range of removal due to new replacement is also reduced. Also, since various pipes are connected to the reactor pressure vessel and the pipes are also arranged through the shielding wall formed around the pressure vessel with a narrow gap, it is necessary to remove the pressure vessel. Considering the simplification of construction work and the shortening of the construction period, it is desirable that the structure around the pressure vessel is not affected.

The present invention was made in consideration of the above circumstances. An object of the present invention is to provide a new reactor pressure vessel replacement method capable of simplifying the work from removal of the pressure vessel to new replacement and shortening the construction period.

[0005]

According to the first aspect of the present invention, there is provided a pressure vessel for replacing a reactor pressure vessel housed in a containment vessel inside a reactor building body surrounded by a reactor shield wall. In the method of removing the outside of the body, after cutting the pipe that penetrates the shielding wall and is connected to the pressure vessel at a position inside the shielding wall to separate it, after releasing the fixation of the pressure vessel installed on the foundation The pressure vessel is lifted to the outside of the containment vessel and the skeleton that are open upward, and is removed.

A second aspect of the present invention is a method of removing the pressure vessel outside the body to replace the reactor pressure vessel which is housed in the containment vessel inside the reactor building body surrounded by the reactor shielding wall. In, the bulkhead that extends horizontally from the containment vessel toward the pressure vessel while cutting and removing the pipes penetrating the shielding wall and connected to the pressure vessel at positions inside and outside the shielding wall, respectively. While leaving a part on the side of the containment vessel, cut at a position outside the shielding wall, lifted up outside the pressure vessel opened upward, and removed, and fixed the pressure vessel and the shielding wall installed on the foundation. After that, the pressure vessel and the shielding wall are lifted up and removed.

[0007]

In the first aspect of the present invention, the pipe that penetrates the shield wall and is connected to the pressure container is an obstacle to removing the pressure container. Therefore, the pipe between the pressure container and the shield wall that covers the pipe is blocked. It is designed to be cut at the position. Therefore, it is possible to remove the pressure vessel while leaving the shielding wall.

In the second aspect of the present invention, in order to remove the shield wall covering the pressure vessel with the removal of the pressure vessel, the pipe passing through the shield wall and connected to the pressure vessel and above the shield wall are provided horizontally from the storage vessel. The extended bulkhead is an obstacle. For this reason, the pipes are cut inside and outside the shielding wall, respectively, and the bulkhead is partially left in the containment vessel and cut outside the shielding wall to separate it from the pressure vessel. is there. Even if the pressure vessel and the shielding wall are removed, a part of the bulkhead remains in the containment vessel, so the bulkhead can be reused by attaching the removed bulkhead to the cutting part at the time of replacement. Becomes

[0009]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, a reactor containment vessel 2 is housed in a reactor building body 1 such as a nuclear power plant, and the reactor containment vessel 2 is covered with a reactor shield wall 3. The opened reactor pressure vessel 4 is stored. When the life of the reactor pressure vessel 4 reaches a life after a predetermined number of years has passed, the used reactor pressure vessel 4 is removed to the outside of the body 1 for a new replacement.

The reactor pressure vessel 4 includes a metal heat insulating material 5 (5a
5e), a bellows 7 is provided between the reactor pressure vessel 4 and a ring-shaped bulkhead 6 extending horizontally from the reactor containment vessel 2 so as to cover the reactor pressure vessel 4. . Further, the reactor pressure vessel 4 has various pipes 8 (8a
8e) are connected, the heat insulating material 5, the bellows 7 and the pipe 8 are removed in order to remove them.

First, as shown in FIG. 2, the reactor pressure vessel 4
The bellows between the bulkhead 6 and the reactor containment vessel 4 extending from the reactor containment vessel 2 so as to cover the nuclear pressure vessel 4 are removed while removing the metal heat insulating material 5 covering the same. Cut 7 and remove. Next, various pipes 8 connected to the reactor pressure vessel 4 are removed. Since these pipes 8 are connected to the nozzle portion 12 formed in the reactor pressure vessel 2 through the elbow 11 penetrating the shield wall 3 covering the reactor pressure vessel 4, the pressure vessel 4 and the shield wall 3 are connected. The nozzle portion 12 between and is melted and separated from the reactor pressure vessel 4. Further, the reactor pressure vessel 4 is fixed to the pedestal 13 which is the base with bolts (not shown). Therefore, if this bolt is removed, the fixation of the reactor pressure vessel 4 on the pedestal 13 can be released. You can

On the other hand, as shown in FIG. 3, an overhead crane 14 is installed in the body 1 above the reactor pressure vessel 4, and the ceiling crane 14 allows the upper lid 1 of the reactor containment vessel 2 to be installed.
5 is lifted to open the storage container 2 upward. The suspended upper lid 15 is a flat mounting portion 1 formed in the body 1.
Temporarily placed at 6. Further, a slide type partition plate 18 that opens and closes the opening 17 is provided on the upper part of the frame 1, and if the partition plate 18 is moved, the upper part of the frame 1 is opened,
The reactor pressure vessel 4 is lifted by a large crane 19 and removed outside the skeleton 1. When the reactor pressure vessel 4 is lifted, the reactor pressure vessel 4 is mounted on the beam 21 above the frame 1.
The sheet-like temporary airlock 22 is covered and removed.

After the removal of the reactor pressure vessel 4 is completed, the new reactor pressure vessel is hoisted on the skeleton 1 by the large crane 19 and carried into the containment vessel 2.

If the pipe 8 connected to the reactor pressure vessel 4 is cut between the pressure vessel 4 and the shielding wall 3 in this way, even if the pressure vessel 4 is removed, the containment vessel 2 having a welded structure is affected. It is possible to remove the reactor pressure vessel 4 with the shielding wall 3 and the various pipes 8 left without being provided, and the shielding wall 3 and the pipe 8 can be reused after a new replacement. In particular, since the shielding wall 3 is made by filling the steel formwork with concrete, if the shielding wall 3 is left, the reactor pressure vessel 4 can be easily removed and the removal period can be shortened. .

Next, the second invention will be described.

In the second aspect of the invention, the shield wall 3 covering the reactor pressure vessel 4 is also removed when the reactor pressure vessel 4 is removed. In the case of using another structure or a thin shielding wall, the shielding wall 4 should be removed together with the removal of the reactor pressure vessel 4.
May be required to be removed.

Therefore, in FIGS. 1 and 2, the metallic heat insulating material 5 is removed and various pipes 8 penetrating the shielding wall 3 and connected to the reactor pressure vessel 4 are shielded as in the first invention. The elbow (hatched portion in the figure) 11 is removed by cutting at the inner and outer positions of the wall 3. In addition, since the bulkhead 6 extending horizontally from the reactor containment vessel 2 so as to cover the reactor shield wall 3 becomes an obstacle in removing the shield wall 3 upward, as shown in FIG. The space between the head 6 and the reactor pressure vessel 4 will be cut and removed. That is, the upper portion of the bellows 7 is attached to the bulkhead 6, and the lower end portion of the bellows 7 is attached to the ring-shaped joining portion 23 that extends horizontally from the reactor pressure vessel 4. The upper part (A in the drawing) is cut, and the connecting portion 23 is cut and removed within the diameter (B in the drawing) of the flange portion 24 of the reactor pressure vessel 4.

Next, as shown in FIGS. 3 and 4, the overhead crane 14 is used to open the upper containment vessel 2.
Then, the upper lid 15 of the reactor containment vessel 2 is hung up and temporarily placed on the placing portion 16 formed on the skeleton 1, the lifting piece 25 is attached to the bulkhead 6, and the bulkhead 6 is hung through the lifting piece 25 to the ceiling. While being held by the crane 14, the bulkhead 6 is cut outside the outer diameter of the reactor shielding wall 3. By this cutting, the bulkhead 6 is separated from the storage container 2 while leaving the base end portion 26 thereof and is suspended from the overhead crane 14. The suspended bulkhead 6 is temporarily placed on the placing portion 16 of the skeleton 1 by the overhead crane 14.

Since the reactor shield wall 3 is fixed on the pedestal 13 with bolts (not shown), the bolts are removed and the reactor shield wall 3 is unfixed.

After that, the reactor pressure vessel 4 is lifted by the large crane 19 and the airlock 2 is moved as in the first invention.
It is covered with 2 and will be removed to the outside of the skeleton 1, but the reactor shield wall 3 will be removed by the large crane 19 after the removal of the reactor pressure vessel 4 or integrally with the reactor pressure vessel 4. Become.

After the reactor pressure vessel 4 and the reactor shield wall 3 are removed, a new reactor pressure vessel and a good shield wall are carried into the containment vessel 2 by the large crane 19. In this case, the bulkhead 6 temporarily placed on the placing portion 16 is lifted by the overhead crane 14 and attached to the base end portion 26 left in the storage container 2 for reuse.

As described above, according to the second aspect of the present invention, when the reactor pressure vessel 4 is removed, even if the reactor shield wall 3 is removed,
Since the bulkhead 6 which is an obstacle in removing the shield wall 3 is cut off at a position outside the shield wall 3 while leaving a part of the bulkhead 6 in the storage container 2, there is no effect on the storage container 2 having a welded structure, and the construction work can be performed. Can be simplified and the construction period can be shortened. In addition, the bulkhead 6 can be reused at the time of new replacement.

[0024]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) In claim 1, since the pipe connected to the reactor pressure vessel is cut between the reactor pressure vessel and the reactor shielding wall covering the same, even if the reactor pressure vessel is removed. Since the influence on the storage container is small and the shielding wall can be left, the removal work can be simplified.

(2) In the second aspect, the bulkhead extending from the containment vessel to the reactor pressure vessel is cut and removed at a position outside the shielding wall while leaving a part of the bulkhead on the side of the containment vessel. Even if the shielding wall is removed, it does not affect the containment vessel, which simplifies the construction work and shortens the construction period, and also enables reuse of the bulkhead.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a stored state of a reactor pressure vessel.

FIG. 2 is a cross-sectional view showing a peripheral structure of a reactor pressure vessel.

FIG. 3 is a cross-sectional view showing a removed state of the reactor pressure vessel.

FIG. 4 is an explanatory diagram showing a second invention.

[Explanation of symbols]

 1 Building 2 Containment Vessel 3 Reactor Shielding Wall 4 Reactor Pressure Vessel 6 Bulkhead 8 Piping 13 Base Pedestal

Claims (2)

[Claims] 1. A method for removing a pressure vessel outside the body to replace a reactor pressure vessel housed in a containment vessel inside a reactor building body surrounded by a reactor shielding wall, After cutting through the pipe connected to the pressure vessel at a position inside the shielding wall to disconnect it, and after releasing the fixation of the pressure vessel installed on the foundation, the pressure vessel is opened to the upper side of the containment vessel and A new method for replacing a reactor pressure vessel, which is characterized in that it is lifted outside the body and removed. 2. A method of removing a pressure vessel outside the body to replace a reactor pressure vessel housed in a containment vessel inside a reactor building body surrounded by a reactor shield wall, While removing the pipes that penetrate through and are connected to the pressure vessel at positions inside and outside the shielding wall, respectively, and at the same time, remove the bulkhead horizontally extending from the containment vessel toward the pressure vessel to the containment vessel side. While leaving a part of it, cut it at a position outside the shielding wall, lift it up and remove it, and after releasing the fixation of the pressure vessel and the shielding wall installed on the foundation, move the pressure vessel and the shielding wall upward. A new method for replacing a reactor pressure vessel, which is characterized in that it is lifted to the outside of an open body and removed.