JP7267894B2 - Dismantling method and equipment for reactor pressure vessel - Google Patents

Description

The present invention relates to a method and apparatus for dismantling a reactor pressure vessel when a nuclear power plant is decommissioned.

(1) of FIG. 13 is a plan view of the operating floor, and (2) is a schematic cross-sectional view of the main part of the reactor building taken along line AA in (1). As shown in the figure, a reactor containment vessel 17 is arranged inside the reactor building 10 , and a reactor pressure vessel 18 is installed on a pedestal 22 within the reactor containment vessel 17 . A reactor heat shield wall 19 is formed around the reactor pressure vessel 18 . Above the reactor pressure vessel 18 is an operating floor (hereinafter sometimes abbreviated as OF) 11 used for operations such as refueling and storage of spent fuel. An overhead crane 23 is installed.
Inside the reactor pressure vessel 18, a dryer (steam dryer), a separator (steam separator), a shroud (a structure for storing fuel), a jet pump, etc., which are called reactor internal structures, are installed. .

Also, in the reactor building 10, a spent fuel storage pool (spent fuel pool: hereinafter sometimes simply abbreviated as SFP) 16 and an equipment storage pool (dryer separator pool: hereinafter sometimes simply abbreviated as DSP) 15 are installed. there is The SFP 16 is mainly intended to store spent fuel, and the DSP 15 is intended to store the dryer and separator during periodic inspections. Between the SFP 16 and the DSP 15 is a reactor well 14 having a wider space than the DSP 15 , and below the reactor well 14 is a reactor containment vessel 17 .

Such nuclear power generation facilities are generally decommissioned and dismantled when the useful life has passed. The dismantling work at this time must be carried out carefully while preventing the scattering of radioactive materials to the outside and the exposure of workers engaged in the dismantling work. In particular, the core internals are highly contaminated, the core portion is waste with a relatively high level of radioactivity (level 1: L1), the waste near the core portion is with a relatively low level of radioactivity (level 2: L2), Others are waste with extremely low levels of radioactivity (Level 3: L3). The same applies to the reactor pressure vessel 18. The core portion is waste with a relatively low level of radioactivity (level 2: L2), and the rest is waste with an extremely low level of radioactivity (level 3: L3).

From the viewpoint of radiation protection, L1 and L2 are disclosed in Patent Document 1 and Patent Document 2 as dismantling by remote control and underwater dismantling. is done in
The reactor internals can be dismantled by filling the equipment storage pool 15, reactor well 14, spent fuel storage pool 16, and reactor pressure vessel 18 with water in the same way as spent fuel replacement. .

However, when dismantling the reactor pressure vessel 18, the bulkhead plate 24 of the reactor well 14 portion is dismantled and removed. It cannot be filled with water. Even if the temporary structure is closed and filled with water, the primary cut piece of the reactor pressure vessel 18 must be lifted up to the operating floor 11 in order to transport it to the equipment storage pool 15 and the spent fuel storage pool 16. not. Even if the waste L2 has a relatively low level of radioactivity, it will be necessary to make adjustments such as suspending the work on the operating floor from the viewpoint of preventing exposure to radiation when it comes out onto the operating floor 11 . In addition, it is necessary to take measures to reduce exposure to radiation, such as covering the dismantled object with a shielding wall, which complicates the procedure and lowers work efficiency.

Considering that the spent fuel storage pool 16 is used for the secondary cutting work, it is assumed that the spent fuel has been carried out of the power plant. There is also a problem that dismantlement of the core internals cannot be started.

In the dismantling method disclosed in Patent Document 3, the temporarily cut reactor pressure vessel 18 is moved to the DSP 15 while keeping it below the floor level of the OF 11, the secondary cutting device installed in the DSP 15 performs the secondary cutting, and then the DSP 15 It is housed in a collection container installed in
However, if the rotary table for secondary cutting is installed in the DSP 15, the work space becomes extremely narrow, and the dismantling means is limited. In addition, if the rotary table is installed in the DSP 15, the space for installing the collection containers becomes narrow, and the number of containers to be temporarily placed is limited. Therefore, during the secondary cutting work, the work of conveying to the outside must also be performed in parallel.

JP-A-2017-67728 Japanese Patent No. 6337410 JP 2019-105584 A

The problem to be solved by the present invention, in view of the above-mentioned problems of the prior art, is to provide a rapid and highly safe reactor pressure vessel while preventing the spread of contamination of the dismantled reactor pressure vessel and reducing the radiation exposure of workers. It is to provide a dismantling construction method and its equipment.

As a first means for solving the above-mentioned problems, the present invention provides a reactor pressure vessel that has been primarily cut into slices and placed on an openable work floor that covers the opening of the reactor containment vessel on the bottom surface of the reactor well. It is an object of the present invention to provide a dismantling method for a reactor pressure vessel characterized by secondary cutting in the axial direction of the reactor pressure vessel (in the direction of the center line of the cylindrical portion of the reactor pressure vessel that has been sliced).
According to the first means, the reactor well, which is wider than the equipment storage pool, can be used as a work area for secondary cutting. Since the wall surface of the reactor well acts as a shielding wall, the risk of radiation exposure is reduced, and work can be performed in parallel with the operating floor, enabling safe work. In addition, since the wall surface of the reactor well becomes a shielding wall, no new shielding measures are required. In addition, by closing the work floor during the secondary cutting, it is possible to prevent accidents caused by falling from the bottom of the reactor well, which is the opening, or by falling objects. In addition, by closing the work floor, it becomes possible to cut the reactor pressure vessel in a state isolated from the reactor well, thereby suppressing the spread of contamination such as dust and gas generated during work. can.

As a second means for solving the above problems, the present invention provides a step of installing an openable work floor so as to cover the opening of the reactor containment vessel on the bottom surface of the reactor well;
a primary cutting step of opening the openable work floor and slicing the reactor pressure vessel into slices while installing the primary cutting means from the opening at the cutting portion of the reactor pressure vessel;
a step of lifting the primary cut reactor pressure vessel into a reactor well below the floor level of the operating floor and closing the openable work floor;
a step of installing the primary cut reactor pressure vessel on the upper surface of the openable work floor;
A step of installing a band saw on the openable work floor to perform secondary cutting in the axial direction of the primary cut reactor pressure vessel;
To provide a method for dismantling a reactor pressure vessel characterized by having
According to the second means, the reactor well, which has a larger space than the equipment storage pool, can be used as a work area for secondary cutting. Since the wall surface of the reactor well acts as a shielding wall, the risk of radiation exposure is reduced, and work can be performed in parallel with the operating floor, enabling safe work. Also, the primary cutting means (apparatus) for the reactor pressure vessel can be installed on the reactor pressure vessel in a state of being suspended by an overhead crane. In addition, it is possible to transfer the first cut, second cut, and cut pieces at a height below the operating floor level, reducing the risk of exposure to work on the operating floor and paralleling the work without affecting the work. work becomes possible. In addition, dismantling work can proceed regardless of the presence or absence of spent fuel in the spent fuel storage pool. In other words, dismantling can be performed without being affected by the process of carrying out the spent fuel.

As a third means for solving the above problems, the present invention provides, in the second means, the primary cutting step is to open the openable work floor to move the primary cutting means above the reactor pressure vessel. To provide a method for dismantling a reactor pressure vessel, characterized in that the dismantling work is carried out with the openable work floor closed after the dismantling of the reactor pressure vessel.
According to the third means, the primary cutting of the reactor pressure vessel can be performed with the work floor closed and the reactor containment vessel sealed, preventing scattering of radioactive substances generated during the primary cutting work. can. This reduces the risk of radiation exposure when working on the operating floor, and allows parallel work without affecting work.

As a fourth means for solving the above problems, the present invention provides the second or third means, wherein the band saw rotates around the axis of the reactor pressure vessel on the openable work floor or It is an object of the present invention to provide a method for dismantling a reactor pressure vessel characterized by performing secondary cutting while advancing and retreating in the radial direction of the reactor pressure vessel.
According to the fourth means, the secondary cutting work can be performed efficiently and in a short period of time, and safety can be ensured while preventing the spread of contamination and reducing exposure of workers.

As a fifth means for solving the above-mentioned problems, the present invention provides a nuclear reactor pressure vessel in which a disposal container is installed in the equipment storage pool and the reactor pressure vessel is secondarily cut in any one of the second to fourth means. is moved in the equipment storage pool below the floor level of the operating floor and stored in the disposal container.
According to the fifth means, a plurality of disposal containers can be installed in the space within the equipment storage pool. In addition, the secondary cutting can be transported at a height below the floor level of the operating floor, reducing the risk of exposure to radiation during work on the operating floor and enabling parallel work without affecting the work.

As a sixth means for solving the above problems, the present invention provides a method for dismantling a reactor pressure vessel in the fifth means, characterized in that the disposal container is temporarily stored in the equipment storage pool. to provide.
According to the sixth means, there is no need to newly secure a place for the disposal container for primary storage. In addition, since the wall surface of the equipment storage pool becomes a shielding wall, no new shielding measures are required.

As a seventh means for solving the above problems, the present invention provides an openable work floor that covers the opening of the reactor containment vessel on the bottom surface of the reactor well,
a base that supports the opening and closing work floor so as to be openable and closable under the openable work floor, has an opening through which the reactor pressure vessel that has been cut into slices passes through, and is installed on the bottom surface of the reactor well;
a band saw for axially secondary cutting the primary cut reactor pressure vessel placed on the openable work floor;
An object of the present invention is to provide a dismantling apparatus for a reactor pressure vessel characterized by:
According to the seventh means, the opening of the bottom of the reactor well can be freely opened and closed by the openable working floor. can be closed and the reactor well, which has a wider space than the equipment storage pool, can be used as a work area for secondary cutting, and waste L2 with a relatively low radioactive level can be cut in the reactor well, and Radiation isolation can be achieved between the reactor pressure vessel and the reactor pressure vessel, which reduces the risk of radiation exposure and allows parallel work with the operating floor, enabling safe work.

According to the present invention, as an eighth means for solving the above problems, in the seventh means, the openable work floor or base is configured so that the band saw rotates around the axis of the nuclear reactor pressure vessel or the nuclear reactor An object of the present invention is to provide a dismantling apparatus for a reactor pressure vessel, which is characterized by having rails capable of advancing and retreating in the radial direction of the pressure vessel.
According to the seventh means, the movement of the band saw, which is the secondary cutting device, can be automated (by remote control), the work can be performed efficiently and in a short time, the diffusion of contamination can be prevented, and the exposure of workers can be reduced. Safety can be ensured while

According to the present invention, the reactor well, which has a larger space than the equipment storage pool, can be utilized as a work area for secondary cutting. In-air disconnection becomes possible without taking new shielding measures, and the reactor pressure vessel can be dismantled without being affected by the process of carrying spent fuel out of the power plant. In addition, since the opening of the reactor containment vessel at the bottom of the reactor well can be closed, safety measures such as prevention of diffusion of dust and gases generated during the primary disconnection of the reactor pressure vessel, falls, and falling of articles can be ensured.

FIG. 1 is an explanatory diagram 1 of a method for dismantling a reactor pressure vessel of Example 1; FIG. 2 is an explanatory diagram 2 of the method for dismantling the reactor pressure vessel of the first embodiment; FIG. 3 is an explanatory diagram 3 of the method for dismantling the reactor pressure vessel of the first embodiment; FIG. 4 is an explanatory diagram 4 of the method for dismantling the reactor pressure vessel of the first embodiment; FIG. 5 is an explanatory diagram 5 of the method for dismantling the reactor pressure vessel of the first embodiment; FIG. 4 is an explanatory diagram of secondary cutting by the band saw of Example 1; FIG. 1 is an explanatory diagram 1 of a method for dismantling a reactor pressure vessel of Embodiment 2; FIG. 2 is an explanatory diagram 2 of the dismantling method of the reactor pressure vessel of the second embodiment; FIG. 3 is an explanatory diagram 3 of the method for dismantling the reactor pressure vessel of Example 2; FIG. 4 is an explanatory diagram 4 of the method for dismantling the reactor pressure vessel of the second embodiment; FIG. 5 is an explanatory drawing 5 of the method for dismantling the reactor pressure vessel of the second embodiment; FIG. 10 is an explanatory diagram of secondary cutting by the band saw of Example 2; It is a schematic cross-sectional view of the main part of the reactor building.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for dismantling a reactor pressure vessel and an apparatus therefor according to the present invention will be described in detail below with reference to the accompanying drawings. In the present invention, a reactor pressure vessel is particularly targeted for dismantling, and the dismantling method will be described below.
In this embodiment, for convenience of explanation, the reactor pressure vessel upper lid 20 and the reactor containment vessel upper lid 21 covering the upper part of the reactor pressure vessel 18 are removed in advance and opened, and the reactor pressure is It is assumed that the reactor internals inside the vessel 18 have been removed (see FIG. 13). Since the nozzle portion of the reactor pressure vessel 18 remains, the bulkhead plate 24 at the bottom of the reactor well 14 is cut to widen the opening so that the cutting member of the reactor pressure vessel 18 can pass through.

[Reactor pressure vessel dismantling device 30]
A reactor pressure vessel dismantling apparatus 30 according to the present invention includes a base 31 which is installed on the bottom surface of a reactor well 14 and has an opening through which the reactor pressure vessel 18 which is primarily cut into slices passes. It has an openable working floor 32 covering the opening of the reactor containment vessel 17 on the bottom of the well 14, and a band saw 33 for secondary cutting along the axis of the reactor pressure vessel 18 (see FIG. 1).

The base 31 has an opening through which the primary reactor pressure vessel 18 cut into slices passes. If the base 31 can be installed around the opening of the reactor containment vessel 17 on the bottom surface of the reactor well 14, the base 31 can be formed in a polygonal shape (square, hexagon, octagon, etc.), circular shape, or the like in plan view. Since the base 31 mounts the openable work floor 32 and the primary cut reactor pressure vessel 18, a steel material having a predetermined strength can be used.

The openable work floor 32 has substantially the same shape as the base 31 in plan view, and serves as a cover for covering the opening of the reactor containment vessel 17 and as a work floor for secondary cutting of the reactor pressure vessel 18 . In addition, the opening/closing work floor 32 is divided into two parts in a plan view, and from the closed state covering the opening of the reactor containment vessel 17 using a winch 37 installed in the OF 11, the reactor pressure vessel 18 in the opening is raised. can be opened and closed in an open state in which is exposed (see FIG. 2). The wire of the winch 37 is connected to a location that does not interfere with the secondary cutting operation by the band saw 33 . The opening/closing work floor 32 is made of lead material, steel material, or the like, which has a shielding effect against radioactive substances.

The band saw 33 has an upper and lower frame, an endless saw blade, and an elevating section for moving the saw blade in the vertical direction. can be cut.
The band saw 33 is installed on the openable work floor 32 that covers the opening of the reactor containment vessel 17, and the primary cut reactor pressure in the reactor well 14 is It is a cutting means capable of secondary cutting (vertical cutting) of the container 18 along the axis.
The band saw 33 also has wheels on its bottom surface that can move on rails 38 installed on the base 31 or the openable work floor 32 . The rails shown in FIGS. 1 to 6 are installed in an annular shape concentrically with the center of the openable work floor 32 . As a result, the band saw 33 can rotate 360 degrees along the axis of the reactor pressure vessel 18 on the working floor.
The base 31 , openable work floor 32 and band saw 33 can all be transported from the OF 11 using an overhead crane 23 and installed at the bottom of the reactor well 14 .

[Reactor Pressure Vessel Dismantling Method]
A dismantling method using the reactor pressure vessel dismantling apparatus 30 of the present invention configured as described above will be described below.

(Example 1)
1 to 5 are explanatory diagrams 1 to 5 of the dismantling method of the reactor pressure vessel of Example 1, (1) in each figure is a plan view of OF, (2) is A- of (1) It is a schematic sectional drawing of A arrow.
As shown in FIG. 1, a base 31, an openable work floor 32, and a band saw 33 are temporarily placed on the OF 11 in advance. Then, the overhead crane 23 is used to install the base 31 on the bottom surface of the reactor well 14 . The base 31 serves as a base on which the openable work floor 32 is installed, and can support the work floor so as to be openable and closable.

As shown in FIG. 2, an openable work floor 32 and a winch 37 serving as an operating mechanism for opening and closing the openable work floor 32 are installed in the OF 11 on a base 31 installed on the bottom surface of the reactor well 14 . After that, the opening/closing operation of the opening/closing work floor 32 is confirmed. Also, a plurality of disposal containers 36 are carried into the DSP 15 .
Next, the primary cutting means is carried into the reactor containment vessel 17, and the primary cutting (horizontal cutting) is performed to slice the reactor pressure vessel 18 into a predetermined size. During the primary cutting work, the openable work floor 32 can be closed to prevent scattering of radioactive substances. Then, as shown in FIG. 3, the opening/closing work floor 32 is opened, and the reactor pressure vessel 18 that has been primarily cut by the ceiling crane 23 is lifted below the floor level of the OF 11 (inside the reactor well 14), and then opened. When the height of the opening/closing work floor 32 is exceeded, the overhead crane 23 is stopped and the opening/closing work floor 32 is closed. The primary cut reactor pressure vessel 18 is suspended on the working floor, and lashed in consideration of the secondary cut position.

As shown in FIG. 4 , the overhead crane 23 is used to install the band saw 33 temporarily placed on the OF 11 on the rails 38 of the openable work floor 32 . After that, connect the power supply and check the operation.
After moving the band saw 33 to the cutting position, it is fixed. A secondary cut (vertical cut) is then made along the axis of the reactor pressure vessel 18 . The cut pieces 35 are sequentially stored in a disposal container 36 within the DSP 15 . At this time, the cut piece 35 is moved below the floor level of the OF 11 (see FIG. 5). The disposal container 36 filled with the cut pieces 35 is moved to the end of the DSP 15 and piled up to a predetermined height with a radiation shielding effect for primary storage. Then, the empty disposal containers 36 are successively carried into the DSP 15, and this operation is repeated until the cut piece 35 disappears. Alternatively, they may be sequentially carried out to the OF 11 and moved to an external storage location.

FIG. 6 is an explanatory view of secondary cutting by the band saw of Example 1. FIG. A band saw 33 is used to make secondary cuts at four points in the diameter direction of the pressure vessel 18 at the same time (see (1) in the figure). After that, the band saw 33 is rotated at a predetermined angle on the rail 38 for secondary cutting (see (2) in FIG. 1). By rotating the band saw 33 by approximately 180°, the entire annular reactor pressure vessel 18 can be secondary cut (see (3) in the figure). After the secondary cutting, the band saw 33 is transported to the OF 11 and removed from the openable work floor 32, and all the cut pieces 35 on the work floor are stored in the disposal container 36 (see (4) in FIG. 1).
Thereafter, the operations of FIGS. 1 to 5 are repeated to completely dismantle the reactor pressure vessel 18 .

(Example 2)
7 to 11 are explanatory diagrams 1 to 5 of the dismantling method of the reactor pressure vessel of Example 2, (1) in each figure is a plan view of OF, (2) is A- of (1) It is a schematic sectional drawing of A arrow.
As shown in FIG. 7, the base 31A of Example 2 is quadrangular in plan view, and has rails 38A on any one of the opposing sides. The rails 38</b>A are configured so that the band saw 33 can move forward and backward (sliding) along the radial direction of the reactor pressure vessel 18 . The opening/closing type work floor 32A is also formed to have substantially the same shape as the base 31A in plan view.
The base 31A, the openable work floor 32A, and the band saw 33 are temporarily placed on the OF 11 in advance. Then, the overhead crane 23 is used to install the base 31A on the bottom surface of the reactor well 14 .

As shown in FIG. 8, an openable working floor 32A and a winch 37 serving as an operating mechanism for opening and closing the openable working floor 32A are installed in the OF 11 on a base 31A installed on the bottom surface of the reactor well 14 . After that, the opening/closing operation of the opening/closing work floor 32 is confirmed. Also, a plurality of disposal containers 36 are carried into the DSP 15 .
Next, the primary cutting means is carried into the reactor containment vessel 17, and the primary cutting (horizontal cutting) is performed to slice the reactor pressure vessel 18 into a predetermined size. During the primary cutting work, the openable work floor 32A can be closed to prevent scattering of radioactive substances. Then, as shown in FIG. 9, the openable work floor 32A is opened, and the reactor pressure vessel 18, which has been primarily cut by the overhead crane 23, is lifted below the floor level of the OF 11 (inside the reactor well), and then opened. When the height of the opening/closing work floor 32A is exceeded, the overhead crane 23 is stopped and the opening/closing work floor 32A is closed. The primary cut reactor pressure vessel 18 is suspended on the working floor, and lashed in consideration of the secondary cut position.

As shown in FIG. 10, the overhead crane 23 is used to install the band saw 33 temporarily placed on the OF 11 on the rail 38 of the base 31A. After that, connect the power supply and check the operation.
After moving the band saw 33 to the cutting position as shown in FIG. 11, it is fixed. A secondary cut (vertical cut) is then made along the axis of the reactor pressure vessel 18 . The cut pieces 35 are sequentially stored in a disposal container 36 within the DSP 15 . At this time, the cut piece 35 is moved below the floor level of the OF 11 . The disposal container 36 filled with the cut pieces 35 is moved to the end of the DSP 15 and piled up to a predetermined height with a radiation shielding effect for primary storage. Then, the empty disposal containers 36 are successively carried into the DSP 15, and this operation is repeated until the cut piece 35 disappears. Alternatively, they may be sequentially carried out to the OF 11 and moved to an external storage location.

FIG. 12 is an explanatory diagram of secondary cutting by the band saw of Example 2. FIG. If the cutting surface of the cut end of the cut piece 35 has an acute angle, the storage efficiency of the disposal container 36 deteriorates.
Therefore, as shown in FIG. 1(1), the first cut is made leaving the central portion. Then, as shown in FIG. 2(2), the band saw 33 is slid to a position line-symmetrical to the first cut to cut the second cut.
As shown in FIG. 3(3), 8 cuts can be made by 2 cutting operations, and a total of 6 cut pieces 35, 3 pieces on each side, can be obtained.
Next, as shown in FIG. 4(4), the rest of the reactor pressure vessel 18 is lifted by the overhead crane 23, rotated 90 degrees, reinstalled, lashed, and cut in the same manner as described above. Since the reactor pressure vessel 18 has a nozzle portion and the like, it is preferable to cut so as to avoid the nozzle portion.
After that, the work shown in FIGS. 7 to 11 is repeated to completely dismantle the reactor pressure vessel 18 .

According to the method and apparatus for dismantling a reactor pressure vessel of the present invention, the reactor well, which has a larger space than the equipment storage pool, can be utilized as a work area for secondary cutting. If it is a relatively low waste L2, it is possible to cut inside the reactor well, and since the wall surface of the reactor well becomes a shielding wall, it is possible to work safely while reducing the risk of radiation exposure when working in parallel with the operating floor. can. In addition, by keeping it closed, it is possible to prevent accidents caused by falling from the bottom of the reactor well, which is an opening, or falling objects. Further, when the primary cutting of the reactor pressure vessel is performed with the openable work floor closed and the reactor containment vessel sealed, it is possible to suppress the spread of contamination such as generated dust and generated gas.

Underwater cutting, such as the conventional dismantling method, requires measures to improve the cleanliness of the water in order to ensure the visibility of the operation, which increases the difficulty of the cutting work. However, if it is in the air like the present invention, such countermeasures become unnecessary, and the cutting work becomes easier. In addition, the wall surface of the reactor well serves as a shielding wall, which serves as a measure to reduce radiation exposure.
Also, if the primary cutting and secondary cutting of the reactor pressure vessel are carried out in parallel, the work of the primary cutting crew and the secondary cutting crew will be carried out continuously and in parallel, thereby improving working efficiency. In addition, since the work is continuous, work proficiency is improved and safety is improved.
The secondary cutting work of the reactor pressure vessel is carried out while moving the band saw, or while rotating the primary cut reactor pressure vessel 18 on the openable work floor 32 with the band saw fixed. A configuration for secondary cutting may also be used.
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention.

INDUSTRIAL APPLICABILITY The method and apparatus for dismantling a reactor pressure vessel according to the present invention have industrial applicability particularly in the field of the nuclear power industry for decommissioning nuclear power plants.

10 Reactor building 11 Operating floor 13 Well cover 14 Reactor well 15 Equipment storage pool 16 Spent fuel storage pool 17 Reactor containment vessel 18 Reactor pressure vessel 19 Heat shield wall 20 Reactor pressure vessel upper lid 21 Reactor containment vessel Upper lid 22 Pedestal 23 Overhead crane 24 Bulkhead plate 30 Dismantling device 31, 31A for reactor pressure vessel Bases 32, 32A Openable work floor 33 Band saw 34 Saw blade 35 Cutting piece 36 Disposal container 37 Winch 38 Rail

Claims (8)

A reactor pressure vessel that has been primarily cut into slices is cut secondarily in the axial direction of the reactor pressure vessel on an openable work floor that covers the opening of the reactor containment vessel at the bottom of the reactor well. Dismantling method of furnace pressure vessel. A step of installing an openable work floor so as to cover the opening of the reactor containment vessel on the bottom surface of the reactor well;
a primary cutting step of opening the openable work floor and slicing the reactor pressure vessel into slices while installing the primary cutting means from the opening at the cutting position of the reactor pressure vessel;
a step of lifting the primary cut reactor pressure vessel into a reactor well below the floor level of the operating floor and closing the openable work floor;
a step of installing the primary cut reactor pressure vessel on the upper surface of the openable work floor;
A step of installing a band saw on the openable work floor to perform secondary cutting in the axial direction of the primary cut reactor pressure vessel;
A method for dismantling a reactor pressure vessel, comprising: A method for dismantling a reactor pressure vessel according to claim 2,
The primary cutting step is performed in a state in which the openable work floor is closed after the primary cutting means is installed on the reactor pressure vessel by opening the openable work floor. Container dismantling method. A method for dismantling a reactor pressure vessel according to claim 2 or 3,
Dismantling of a reactor pressure vessel, wherein the band saw performs secondary cutting while rotating about the axis of the reactor pressure vessel or moving forward and backward in the radial direction of the reactor pressure vessel on the openable work floor. Construction method. A method for dismantling a reactor pressure vessel according to any one of claims 2 to 4,
A reactor pressure vessel in which a disposal container is installed in an equipment storage pool, and the secondary cut reactor pressure vessel is moved in the equipment storage pool below the floor level of the operating floor and stored in the disposal container. demolition method. A method for dismantling a reactor pressure vessel according to claim 5,
A dismantling method for a nuclear reactor pressure vessel, characterized in that the disposal container is temporarily stored in the equipment storage pool. A retractable work floor covering the opening of the reactor containment vessel on the bottom surface of the reactor well;
a base that supports the opening and closing work floor so as to be openable and closable under the openable work floor, has an opening through which the reactor pressure vessel that has been cut into slices passes through, and is installed on the bottom surface of the reactor well;
a band saw for axially secondary-cutting the primary-cut reactor pressure vessel placed on the openable work floor;
A dismantling device for a reactor pressure vessel, comprising: In the reactor pressure vessel dismantling apparatus according to claim 7,
The reactor pressure vessel, wherein the openable work floor or base includes a rail that allows the band saw to rotate about the axis of the reactor pressure vessel or move forward and backward in radial directions of the reactor pressure vessel. demolition equipment.

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