JP2519896B2 - Reactor dismantling method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for dismantling a nuclear reactor in a nuclear power plant or the like.

“Prior Art” It is expected that the reactors currently in operation will need to take decommissioning measures for aging or model changes in the future. Various studies have been made on the construction method.

Against this background, as the most commonly known dismantling method, the activated structural parts are cut into fine blocks with a cutting device equipped with a remote control device, and each block is stored in a cask and the atom is stored. The construction method is to take it out of the reactor building, transport it to a designated final disposal facility, and store it.

However, when carrying out the above-mentioned construction method, there is a problem that a cutting device equipped with a highly accurate remote control function is required, and in addition, since it is necessary to cut out a large number of blocks,
There is a problem that the number of blocks increases and the carrying out work and the transportation work become complicated.

Therefore, in order to solve these problems, the applicant of the present invention forms a temporary transfer hole in the wall of the reactor building, separates the biological shielding wall from the reactor building body, and laterally installs the storage container together with the biological shielding wall. A construction method of sliding in the direction and carrying out from the carrying hole has been previously proposed.

[Problems to be Solved by the Invention] The above-mentioned construction method previously proposed by the applicant of the present invention is a construction method in which the living body shielding wall is regarded as a cask and the reactor along with the living body shielding wall can be carried out in a large block. It was a construction method that simplified the decommissioning work by increasing the size of the building and reducing the number of unloading work.

However, the above-mentioned construction method requires a space for moving a large block to the side of the reactor building wall, so a nuclear power generation facility constructed adjacent to another building on the side of the reactor building. There was a problem that was difficult to implement.

The present invention has been made in view of the above problems, a space for moving a dismantled object as a large block as in the case where another building is adjacently constructed on the side of the reactor building to be dismantled. Even if it is not possible to secure it on the side of the reactor building, it is possible to carry out dismantled objects in large blocks instead of making them into small blocks, thus enabling efficient decommissioning work. It is an object of the present invention to provide an effective method for dismantling a nuclear reactor.

[Means for Solving Problems] In order to solve the above problems, the present invention forms a temporary opening that can be opened and closed on the roof of a reactor building, and the reactor containment vessel through this opening. The cask is carried into the space for work above, the radioactive demolition material is carried into and stored in the cask using the lifting machine, and the cask is carried out of the reactor building through the opening. It is a thing.

“Operation” In order to carry in and carry out the cask through the opening formed in the ceiling of the reactor building, in the nuclear power generation facility etc. where another building is constructed adjacent to the reactor building, When dismantling, other buildings will not interfere with the loading and unloading of casks. Also, because a large opening can be easily formed in the ceiling, a large cask can be loaded into and unloaded from the reactor building, and the radioactive demolition object can be kept large without cutting it into small pieces. It can be stored in a cask and carried out, and the operation of storing the dismantled object in the cask can be performed using a lifting machine provided in the cask. Furthermore, if the opening is closed by the door after transporting the cask into the building,
Safety can be improved because storage work can be performed in the cask while preventing leakage of radioactivity.

"Embodiment" FIGS. 1 to 7 show an embodiment in which the present invention is applied to the dismantling of a nuclear power plant equipped with a Mark-II type reactor containment vessel in the order of steps.

FIG. 1 shows the reactor building A immediately before the start of dismantling work. This reactor building A is configured such that a pressure vessel 1 and a steel containment vessel 2 equipped with various devices are provided inside, and a concrete biological shielding wall 3 surrounding the containment vessel 2 is surrounded by a building skeleton 4. ing. Further, the living body shielding wall is formed with a spent fuel pool 5 and a temporary reactor equipment temporary pool 6 and the like on the side of the cylindrical portion 3a at the upper end of 3, and these pools 5 and 6, the containment vessel 2 and the reactor. Between the ceiling part 7 of the building A, a work space 8 for performing a fuel exchange work or the like is formed.
A shield plug 9 is fitted inside the tubular portion 3a of the biological shield wall 3.

When the dismantling work is performed in the reactor building A having the structure shown in FIG. 1, first, before the dismantling work, a position on the corner side of the ceiling portion 7 of the reactor building A, which is located immediately above the shield plug 9. A temporary opening 10 that is larger than the opening of the tubular portion 3a of the living body shielding wall 3 is formed in the living body shielding wall 3, and a slide type opening / closing door 11 that hermetically closes the opening 10 is provided at the upper opening of the opening 10. The opening / closing door 11 is provided in order to prevent the radioactivity from leaking from the opening 10 during the dismantling work described later by closing the opening 10.

Next, a box-shaped cask (transfer chamber) 12 having a bottom opening type and made of a member having a radiation shielding ability is prepared. This cask 12 is a large one that can pass through the opening 10, and a slide type opening / closing door 14 is provided in the bottom opening, a traveling device is attached to the bottom side, and an inner ceiling is provided. Lifting machines such as cranes 17
Is provided, and a metal fitting for hanging is attached to the upper surface of the outside.

Then, in order to perform the dismantling work, as shown in FIG. 2, the door 11 of the reactor building A is opened, the cask 12 is lifted by a lifting machine 13 such as a crane, and the cask 12 is opened from the opening 10 to the reactor building A. It is hung on the corner side of the space 8.

After the cask 12 is hung in the space 8, the opening / closing door 11 closes the opening 10 of the ceiling 7. Further, the shield plug 9 is removed and the tubular portion 3a of the living body shielding wall 3 is opened.

Next, the cask 12 is caused to travel along the floor below the space portion 8 and moved onto the tubular portion 3a opened as described above.

Next, as shown in FIG. 3, the opening / closing door 14 of the cask 12 is opened, and the radioactive demolition object 18 stored inside the storage container 2 is opened.
Is lifted by a lifting machine 17 and stored inside the cask 12. Here, the cask 12 is a large one, and the storage container 2
In order to be able to store the large radioactive demolition material 18 installed inside the
It can be stored in a large size without cutting it into small pieces.

After the radioactive demolition material 18 is stored in the cask 12, the opening / closing door 14 is closed to seal the cask 12 as shown in FIG. 4 to prevent radiation leakage.

Next, as shown in FIG. 5, the cask 12 is moved below the opening 10, and the cylindrical portion 3a of the biological shield wall 3 is closed by the shield plug 9 to prevent the leakage of radiation from the inside of the storage container. .

Subsequently, the opening / closing door 11 is opened, the cask 12 is lifted by the lifting machine 13 as shown in FIG. 6, and is carried out from the reactor building A through the opening 10. In the dismantling work, a plurality of the casks 12 are prepared, the plurality of casks 12 are sequentially carried into the space portion 8 of the reactor building A, and not only the radioactive dismantled material inside the biological shielding wall 3 but also the pool 5 Then, the radioactive demolition materials temporarily stored at 6 and 6 are also stored and then sequentially carried out of the reactor building A, transported to the waste treatment facility 20 and disposed of, and the demolition work proceeds.

Next, the cask carried out from the reactor building A as described above
12 is transported to a predetermined waste treatment facility 20 by a transportation machine 19 such as a truck. Then, in this waste treatment facility 20, the radioactive demolition material 18 is finely disassembled and disposed of. In this way, a radioactive waste dismantling material 18 with the highest radioactive level that has been carried out from the inside of the PCV 2 is installed in a waste treatment facility.
The radioactive demolition material 18 can be safely dismantled for disposal at 20.

The opening formed in the ceiling part 7 of the reactor building A as described above
If the cask 12 is loaded and unloaded using 10 to dismantle the reactor, the dismantled material will be removed as if another building was constructed next to the reactor building A. Even in a nuclear power generation facility having a structure in which a space for moving laterally cannot be secured, if there is a space above the reactor building A, a large cask 12 can be used. Since the dismantled object can be stored in a large block as it is in a large block and carried out, it is not necessary to cut it into many small blocks as in the past, and as a result, cutting work and carrying-out work can be significantly done. It can be implemented efficiently.

In the embodiment, the present invention is applied to the dismantling of the reactor equipped with the Mark-II type containment vessel, but the present invention is applied to the dismantling of the BWR, such as a reactor equipped with the Mark-I type containment vessel. Of course you can.

"Effects of the Invention" As described above, the present invention brings a cask into the building through an opening formed in the ceiling of the reactor building, stores the radioactive demolition object in the cask, and later Since it is carried out through the opening for dismantling work, the dismantled object is moved to the side and discharged as in the case where another building is constructed adjacent to the reactor building. If the space above the reactor building is open even in a nuclear power generation facility where a space for
The dismantling work can be performed without disturbing other buildings.

In addition, the opening formed in the ceiling can be easily enlarged, and since it is possible to carry a large cask into the building, it is not necessary to cut the radioactive demolition material into small pieces. Objects can be stored in a large cask as a large block and carried out, and the demolition object can be stored in the cask by a lifting machine provided on the cask. When it is not possible to slide it to the side while keeping it large, it is possible to perform cutting work and carrying out work more efficiently than in the conventional case where it had to be cut out into many small blocks and carried out. effective.

Furthermore, after carrying in the cask inside the reactor building,
If you close the opening formed on the roof with the door,
There is no radioactive leakage during the work of loading the radioactive demolition material into the cask, and there is an effect that the demolition work can be carried out safely.

[Brief description of drawings]

1 to 7 show an embodiment of the present invention. FIG. 1 is a sectional view showing the upper part of the reactor building, and FIG. 2 shows a state in which a cask is being carried into the reactor building. FIG. 3 is a sectional view showing a state in which the cask is moved above the storage container, FIG. 4 is a sectional view showing a state in which the radioactive demolition object is stored in the cask, and FIG. 5 is a diagram showing the radioactive demolition object. Sectional view showing the moving state of the stored cask, FIG. 6 is a sectional view showing the state of carrying out the cask from the reactor building, and FIG. 7 is a side view showing the state of transporting the cask to the waste treatment plant. It is a figure. A: Reactor building, 1 ... Pressure vessel, 2 ... Containment vessel,
3 ... biological barrier, 4 ... body, 7 ... ceiling, 8 ...
Space, 10 …… Opening, 11 …… Opening door, 12 …… Cask, 13 …… Hoisting machine, 14 …… Opening door, 17 …… Hoisting machine, 18…
… Radioactive demolition, 20… Waste treatment facility.

Claims (1)

(57) [Claims] 1. A temporary opening that can be opened and closed is formed on the roof of a reactor building, and a cask equipped with a lifting machine is carried into the working space above the reactor containment vessel through this opening. Then, the radioactive demolition object is carried in and stored in the cask by using the lifting machine, and the cask is carried out to the outside of the reactor building through the opening.