JP2015152387A - Nuclear reactor dismantlement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nuclear reactor dismantlement method capable of reducing the oppression of dismantled matters to the floor surface space within a torus room.SOLUTION: A method of dismantling a nuclear reactor including a torus room accommodating therein a suppression chamber communicating with a reactor containment vessel via a vent pipe, comprises: a first step of partially dismantling a structure in the torus chamber containing the suppression chamber; and a second step of safekeeping dismantled matters generated by dismantlement using at least part of a space surrounded by a casing of the suppression chamber in the torus room or a space surrounded by a casing.

Description

  The present invention relates to a nuclear reactor removal method.

  Nuclear reactors and other nuclear reactor equipment will be decommissioned when the operation mission ends. For this reason, there is an urgent need to establish a safe and rational dismantling and removal method for reactor pressure vessels accompanying decommissioning of reactors. In order to dismantle and remove the reactor pressure vessel, it is considered realistic to subdivide the reactor pressure vessel and remove and dispose of it sequentially. Patent Document 1 discloses a method for removing a reactor pressure vessel from a reactor building of a boiling water reactor type nuclear power plant facility.

  As described in Patent Document 1, this decommissioning is performed in the order of system decontamination, safe storage, and dismantling and removal. In safe storage, it is stored until the radiation level of the equipment decays to a predetermined value (about 5 to 10 years). After that, the piping and equipment are disassembled, and the reactor pressure vessel, which is heavy, is disassembled. The dismantling removal work to subdivide this and remove it from the reactor building is performed. In the demolition removal work, the demolition is stored in a radiation shielding container in the reactor building, and is transferred to a storage facility such as a turbine building or a radiation control building for temporary storage. Thereafter, the radiation shielding container is transported to a predetermined place by a ship and buried in the ground.

  In Patent Document 1, a tunnel that directly connects a reactor building and a turbine building constructed in a nuclear power plant facility in order to efficiently transfer a demolished material dismantled in the reactor building from a reactor building to a storage facility. (Main steam tunnel) is used as a passage for unloading the reactor pressure vessel stored in the reactor building, and the reactor removal method is used to transfer the dismantled material to the turbine building through the tunnel and store it. It is disclosed.

Japanese Patent No. 4898567

In the above prior art, the turbine building must be dismantled in advance in order to secure a space for storing the dismantled material in the turbine building. The flow line (main steam tunnel) for carrying out the demolition cannot be secured.
Therefore, in order to perform dismantling work inside the reactor building without waiting for the dismantling of the turbine building, the torus chamber containing the suppression chamber communicating with the reactor containment vessel and the vent pipe is dismantled in advance, and the torus It may be possible to access the ground using the existing facilities attached to the room and secure another flow line that does not directly connect the reactor building to the turbine building.

  When disassembling the torus chamber in advance, it is necessary to disassemble the structure in the torus chamber, shred the dismantled material, store the shredded material in the container, and store the stored container. Necessary work space is required. The stored containers that have been stored are carried out to the outside through the flow line, but must be stored in the torus room until the final disposal site for the dismantled material is determined. In such a case, when the structure in the torus room is completely dismantled, the floor space in the torus room is compressed by the dismantled object. In this case, there is a problem that it is difficult to secure a work space and a flow line space, and it is difficult to secure a prior dismantling and a flow line in the torus room.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a reactor removal method that can reduce the pressure on the floor space in the torus room caused by the dismantled material.

In order to solve the above-described problems, the present invention provides a method for removing a nuclear reactor having a torus chamber in which a suppression chamber communicating with a reactor containment vessel and a vent pipe is accommodated, and includes the suppression chamber. A first step of partially disassembling the structure in the torus chamber, and a space surrounded by a housing of the suppression chamber in the torus chamber or a space surrounded by the housing in the torus chamber And a second step of storing using at least a part of the method.
By adopting this method, in the present invention, the structure in the torus chamber including the suppression chamber is not disassembled at once, but partially disassembled, thereby reducing the dismantled material generated by disassembly and Reduce pressure on floor space. In the present invention, the dismantled material is stored in the space surrounded by the housing of the suppression chamber, which is the largest structure in the torus room, or in the space surrounded by the housing, thereby filling the dismantled material in the torus room. Increase the rate and reduce the pressure on the floor space in the torus room.

In the present invention, the suppression chamber is self-supporting via a support leg in the torus chamber, and the first step includes a step of partially disassembling a lower portion of the suppression chamber, and the second step. The step employs a technique in which the dismantled product includes a step of storing the dismantled material in a space below the suppression chamber that is self-supporting in a roof shape through the support leg by the dismantling.
By adopting this method, in the present invention, the lower part of the suppression chamber is disassembled while maintaining the self-supporting function by the support legs, and the dismantled product is stored in a space below the roof-shaped suppression chamber. As a result, in the present invention, the disassembled material is reduced without disassembling the upper portion of the suppression chamber, the filling rate of the disassembled material in the torus chamber is increased, and the pressure on the floor space in the torus chamber is reduced.

In the present invention, the support legs are provided in pairs so as to face each other in the width direction of the suppression chamber, and the first step includes the support legs provided in the pairs. A method is adopted in which at least one of them is partially disassembled to include a step of increasing the interval between the support legs in the width direction.
By adopting this method, in the present invention, the pair of support legs that support the suppression chamber is partially disassembled, and the interval between the support legs is increased, so that the lower part of the roof-shaped suppression chamber is located below. Make space easier to use. For example, by increasing the interval between the support legs, it is easy to enter a forklift or the like, and the efficiency of the work of filling the dismantled material in the space below the roof-shaped suppression chamber is improved.

Further, in the present invention, the suppression chamber holds pool water in a space surrounded by the casing, and the second step is a step of storing the dismantled product in the pool water. The method of including is adopted.
By adopting this method, in the present invention, the dismantled material is submerged in the pool water of the suppression chamber, and the dismantled material is stored in a space surrounded by the housing of the suppression chamber. Increase the rate and reduce the pressure on the floor space in the torus room.

Further, in the present invention, the first step includes a step of partially disassembling an upper portion of the suppression chamber that holds the pool water, and a partial disassembly of the upper portion of the suppression chamber according to the weight of the pool water. And a step of reinforcing the casing so as not to buckle.
By adopting this method, in the present invention, the upper portion of the suppression chamber is disassembled while maintaining the pool water retention function while leaving the lower portion of the suppression chamber. Further, when the upper portion of the suppression chamber is disassembled, the structural strength may be reduced, and thus the housing is reinforced so as not to buckle. As a result, in the present invention, the dismantled material is reduced without dismantling the lower part of the suppression chamber, thereby reducing the pressure on the floor space in the torus chamber, and the pool water retention function allows for the disposal of pool water. This pretreatment can be performed in parallel with the dismantling of the structure in the torus chamber.

In the present invention, the suppression chamber is self-supporting in the torus chamber via a supporting leg, and the first step includes a step of partially disassembling the upper portion of the suppression chamber, A process employ | adopts the method of storing the said dismantled thing on the said suppression chamber which becomes self-supporting in the shape of a bowl via the said support leg by the said dismantling.
By adopting this method, in the present invention, the upper part of the suppression chamber is disassembled while maintaining the self-supporting function by the support legs, and the dismantled material is stored on the saddle-shaped suppression chamber. As a result, in the present invention, the disassembled material is reduced without disassembling the lower portion of the suppression chamber, the filling rate of the dismantled material in the torus chamber is increased, and the pressure on the floor space in the torus chamber is reduced.

In the present invention, the torus chamber has an annular area that accommodates the suppression chamber, and the first step includes a step of disassembling the structure in a part of the annular area. The second step includes a step of temporarily placing the demolished material in the partial area in another area, and a step of providing a scrap yard for storing the demolished material in the partial area. The method of including is adopted.
By adopting this method, in the present invention, a structure in a part of the annular area of the torus chamber is disassembled, the dismantled product is temporarily placed in another area, and a scrap yard is provided in the disassembled area. By providing the scrap yard, the storage operation for storing the dismantled material in the container is postponed, and then the carry-out operation for unloading the dismantled material is made to be just-in-time. As a result, the number of dismantled items stored in the torus room is reduced, and the pressure on the floor space in the torus room is reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the pressure of the floor space in the torus room by a dismantled object can be reduced, and the prior dismantling and flow line in a torus room can be ensured.

It is sectional drawing which shows schematic structure of the nuclear reactor in 1st Embodiment of this invention. It is an arrow AA figure in FIG. It is a figure for demonstrating the removal of the demolition thing using the appendage of the removal method of the reactor in 1st Embodiment of this invention. It is a figure which shows the work flow of the incomplete dismantling method in 1st Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 1st Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 1st Embodiment of this invention. It is a figure which shows the work flow of the incomplete dismantling method in 2nd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 2nd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 2nd Embodiment of this invention. It is a figure which shows the work flow of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention. It is a figure for comparing the work flow of the incomplete dismantling method in the 3rd Embodiment of this invention, and a conventional method.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of a nuclear reactor according to a first embodiment of the present invention. 2 is an arrow AA diagram in FIG.
The nuclear reactor according to the present embodiment is related to a boiling water nuclear power generation facility, and a turbine building (not shown) is provided around the reactor.

  As shown in FIG. 1, this nuclear reactor includes a nuclear reactor pressure vessel 1 (RPV) and a steel reactor containment vessel 2 (PCV) provided surrounding the reactor pressure vessel 1. The reactor containment vessel 2 primarily stores the reactor pressure vessel 1 and forms a pressure barrier and a barrier against the release of radioactive materials when the coolant is lost. The reactor containment vessel 2 is a steel self-supporting containment vessel whose base is supported by the reactor building foundation.

  The reactor containment vessel 2 is provided in a concrete reactor building 3 (R / B) as a radioactive shield. The periphery of the reactor containment vessel 2 is thickly covered with a biological shielding wall 3a that forms a part of the reactor building 3, and the radioactive contamination area and the clean area are isolated by the biological shielding wall 3a. The nuclear reactor containment vessel 2 includes a pressure suppression system including a dry well 4 (D / W), a suppression chamber 5 (S / C), and a vent pipe 6.

As shown in FIG. 2, the suppression chamber 5 is made of a steel pipe disposed in an annular shape around the reactor containment vessel 2. The suppression chamber 5 communicates with the dry well 4 of the reactor containment vessel 2 through a plurality of vent pipes 6 (not shown in FIG. 2, see FIG. 1).
The vent pipe 6 is made of a large diameter steel pipe having an inner diameter of about 2 m. The vent pipe 6 connects the space of the dry well 4 and the underwater of the suppression chamber 5.

  The vent pipe 6 has a vent header 7 and a downcomer 8. The vent header 7 is provided in an annular shape in the suppression chamber 5 and is connected to a plurality of vent pipes 6. The downcomer 8 is provided so as to branch from the vent header 7 and open into the pool water P of the suppression chamber 5. A plurality of downcomers 8 are provided between the adjacent vent pipes 6.

  An internal corridor 13 is provided in the suppression chamber 5. The internal corridor 13 is provided above the pool water P so as to be able to circulate inside the suppression chamber 5. On the other hand, an external corridor 14 is provided outside the suppression chamber 5. The external corridor 14 is provided above the suppression chamber 5 so as to be able to go around the outside of the suppression chamber 5. The suppression chamber 5 is self-supporting via a support leg 19 in the torus chamber 9.

  In the basement of the reactor building 3, a torus chamber 9 that is located around the lower portion of the reactor containment vessel 2 and that contains the suppression chamber 5 is provided in an annular shape. The torus chamber 9 has a space cross-sectional area of, for example, about 8 m in height and 8 m in width, and forms a torus-shaped space having a diameter of 30 m to 40 m around the reactor containment vessel 2. The torus chamber 9 is formed as an underground structure that forms part of a concrete reactor building 3 as a radioactive shield.

  The reactor building 3 is provided with an appendage 10 (attached chamber) that is attached to the side of the torus chamber 9 and communicates with the ground outside the reactor building 3. The appendage 10 is an underground structure attached so as to protrude outside the torus chamber 9. This appendage 10 is a core spray pump chamber for accommodating a core spray pump 11 that constitutes a part of an emergency core cooling system (ECCS).

  In addition to the core spray pump 11, the appendage 10 accommodates a heat exchanger, a drain tank, a drain pump, and the like (all not shown) that also constitute an emergency core cooling system. The appendage 10 includes an upper basement floor 10a and a lower basement floor 10b, which can be reached by a ladder (not shown). A core spray pump 11 is disposed on the lower basement floor 10b.

  A communication port 16 that can communicate with the torus chamber 9 is formed at the side of the upper underground floor 10a. A hatch 17a that can communicate with the ground outside the reactor building 3 is provided at the top of the upper underground floor 10a. The hatch 17a can be opened with a size capable of transferring the core spray pump 11 or the like, for example, a size of about 2 m × 2 m. As shown in FIG. 2, two appendages 10 are provided beside the torus chamber 9. The torus chamber 9 is provided with a communication port 18 that communicates with a main steam tunnel (not shown) connected to the turbine building.

Next, a method for removing the reactor having the above-described configuration will be described.
FIG. 3 is a diagram for explaining the removal of the dismantled object X using the appendage 10 of the nuclear reactor removal method in the first embodiment of the present invention.
In this method, first, after decontamination in the furnace, system decontamination, and water treatment in the suppression chamber 5, the suppression chamber 5 is disassembled in advance as shown in FIG. When the suppression chamber 5 is disassembled in advance, the vent pipe 6, the torus chamber 9, and the appendage 10 can be communicated with each other. Thereby, the flow line 20 for carrying in / out connected from the inside of the reactor containment vessel 2 to the ground outside the reactor building 3 can be secured.

  The flow line 20 is formed using the vent pipe 6, the torus chamber 9, and the appendage 10 which are existing structures. In addition, in order to ensure the space cross-sectional area in the flow line 20, it is preferable that the vent header 7 and the downcomer 8 are removed by cutting together with the disassembly of the suppression chamber 5. If necessary, the communication port 16 between the torus chamber 9 and the appendage 10 may be enlarged. The appendage 10 is a core spray pump chamber and is provided with a large hatch 17a serving as a carry-out port, and is suitable for use as a flow line.

In this way, by using the existing structure and securing another flow line in which the reactor building 3 and the turbine building are not directly connected, the dismantling in the reactor building 3 can be performed without waiting for the dismantling of the turbine building. Work can be done. For this reason, it becomes possible to perform dismantling work in parallel with the turbine building side.
When the reactor pressure vessel 1 is dismantled, radioactive suspended matter generated at the time of dismantling leaks from the reactor building 3 to the ground via the flow line 20. Therefore, in this method, the hatch 17a is enclosed before dismantling. A garage 21 is temporarily installed. The garage 21 is for the transport vehicle T that transports the dismantled object X to the outside, and is provided on the ground so as to communicate with the appendage 10. The garage 21 is provided with a shutter 22, and the shutter 22 is closed when the transport vehicle T receives the cargo.

  The dismantled material X of the reactor pressure vessel 1 subdivided in the reactor containment vessel 2 is carried out by providing a lifting machine 24 at an appropriate position on the flow line 20. Specifically, the lifting machine 24 is installed on a rail 25 that is constructed so that the vent pipe 6 passes between the reactor containment vessel 2 and the torus chamber 9, and the demolition X is carried out to the torus chamber 9. In addition, a lifting machine 24 is installed on a rail 26 installed so that the communication port 16 passes between the torus chamber 9 and the appendage 10, and the container storing the dismantled product X in the torus chamber 9 is carried out to the appendage 10. And the lifting machine 24 is installed in the rail 27 erected in the garage 21, and the dismantled object X is pulled up to the ground and placed on the loading platform of the transport vehicle T to carry out.

  In this way, in this method, the inside of the torus chamber 9 is dismantled first, and by securing another independent flow line 20 in which the reactor building 3 and the turbine building are not directly connected, without waiting for the dismantling of the turbine building, Dismantling work in the reactor building 3 can be performed. In addition, since a large space of the torus chamber 9 can be used, waste material processing can be performed until the final disposal site is determined, and the dismantled material X subjected to the waste material processing is stored in the reactor building 3. be able to.

  By the way, the structure in the torus chamber 9 includes a structure that is not effective in securing a work space or a flow line space. As such a structure, for example, it is a high part in the torus chamber 9 and a part that does not compress the floor space in that state, a valve or the like, and must be disassembled into a large number of members. There are parts, etc., where the ratio cannot be secured. If such a structure is dismantled, the floor space in the torus chamber 9 is compressed, and a work space and a flow line space cannot be secured. It becomes difficult to secure.

Therefore, in this method, an incomplete dismantling method that partially disassembles the structure in the torus chamber 9 is adopted. The incomplete dismantling method described below with reference to FIGS. 4 to 6 is after the pool water P of the suppression chamber 5 has been transferred.
FIG. 4 is a diagram showing a work flow of the incomplete dismantling method according to the first embodiment of the present invention. 5 and 6 are schematic diagrams for explaining the work process of the incomplete dismantling method in the first embodiment of the present invention.

  In this method, first, the work space in the torus room 9 is maintained and the dismantling materials and equipment are carried in (step S1). Dismantling materials and equipment can be carried in via the appendage 10. This dismantling material includes a rail 30 and a lifting machine 31 shown in FIG. 5A, and these are installed inside the upper portion 5 a of the suppression chamber 5. The rail 30 extends in the longitudinal direction (ring circumferential direction) of the suppression chamber 5. The lifting machine 31 can move along the rail in the longitudinal direction of the suppression chamber 5 (perpendicular to the plane of the drawing in FIG. 5A), and the suspension point can be moved in the width direction of the suppression chamber 5 (see FIG. 5A). It can be moved in the horizontal direction).

  Next, the support leg 19 of the suppression chamber 5 is slimmed and the step on the floor surface of the torus chamber 9 is removed (step S2: first step). This step S2 enables the forklift or the like to travel in a later process. In the present embodiment, the support legs 19 are provided in pairs so as to face each other in the width direction of the suppression chamber 5 as shown in FIG. In this step S2, at least one of the support legs 19 provided as a pair (both in the present embodiment) is partially disassembled to increase the interval between the support legs 19 in the width direction. This makes it easy to utilize the space below the suppression chamber 5.

  Next, the part to be dismantled is reinforced (step S3). This step S3 reinforces the structure as necessary in order to maintain the function of supporting the weight of the suppression chamber 5 in a later process. For example, the support leg 19 is reinforced by constructing a support outside the slimmed support leg 19. In addition, for example, a support is also applied to the vent pipe 6 and the vent header 7 as necessary to reinforce them.

  Next, the lower part 5b of the suppression chamber 5 is disassembled and the downcomer 8 and the like are cut (step S4: first step). This step S3 partially disassembles the structure in the torus chamber 9 including the suppression chamber 5. When the lower portion 5b of the suppression chamber 5 is disassembled, as shown in FIG. 6A, the upper portion 5a of the suppression chamber 5 remains, and the suppression chamber 5 supported by the support legs 19 becomes self-supporting in a roof shape. As a result, the space s1 surrounded by the casing (shell) of the suppression chamber 5 is opened, and a large space is formed below the roof-shaped suppression chamber 5.

  Next, the interfering substance in the container loading / unloading is removed (step S5). This step S5 removes the structure which interferes in the case of a container carrying in / out from the ceiling of the torus room 9, or the appendage 10. FIG. This container accommodates the dismantled product X generated in step S2, step S4, and the like.

  Finally, the space below the roof-shaped suppression chamber 5 is maintained as a temporary storage place, and the dismantled product X accommodated in the container is stored (step S6: second step). In step S6, as shown in FIG. 6B, the dismantled product X is stored by using at least a part of the space s1 surrounded by the casing of the suppression chamber 5 in the torus chamber 9. The dismantled product X accommodated in the container is stored in a multi-stage stack using a lifting machine 31, a forklift, or the like in a space below the roof-like suppression chamber 5. In addition, the container piled up in this way can be used as a scaffold, and can be used for full-scale dismantling such as dismantling of the upper portion 5a of the suppression chamber 5 in a later process.

  As described above, according to this incomplete dismantling method, the dismantled product X generated by the dismantling is obtained by partially dismantling the structure in the torus chamber 9 including the suppression chamber 5 instead of dismantling all at once. It is possible to reduce the pressure on the floor space in the torus chamber 9. Further, by storing the dismantled object X in the space s1 surrounded by the casing of the suppression chamber 5 which is the largest structure in the torus chamber 9, the filling rate of the dismantled object X in the torus chamber 9 is increased, The pressure on the floor space in the torus chamber 9 can be reduced.

  Specifically, as shown in FIG. 6 (b), the lower portion 5b of the suppression chamber 5 is disassembled while maintaining the self-supporting function by the support legs 19, and the dismantled material is disposed in the space below the roof-shaped suppression chamber 5. Store X. Thereby, while reducing the dismantled object X without disassembling the upper part 5a of the suppression chamber 5 which is not effective for securing the work space and the flow line space, the filling rate of the dismantled object X in the torus chamber 9 is increased, and the torus chamber The pressure on the floor space in 9 can be reduced.

  Further, in this incomplete dismantling method, the pair of support legs 19 that support the suppression chamber 5 are partially disassembled, and the interval between the support legs 19 is increased to lower the roof-shaped suppression chamber 5 below. Make it easier to use the space. As shown in FIG. 6A, by increasing the distance between the support legs 19, the forklift or the like can easily enter, and the efficiency of the work of filling the dismantled object X in the space below the roof-shaped suppression chamber 5 is improved. Can be achieved.

Thus, according to the above-described embodiment, the reactor removal method includes the torus chamber 9 in which the suppression chamber 5 communicating with the reactor containment vessel 2 and the vent pipe 6 is accommodated. A first step of partially disassembling the structure in the torus chamber 9 including 5 and at least the space s1 surrounded by the housing of the suppression chamber 5 in the torus chamber 9 By adopting a method of having a second step of storing using a part of the torus chamber 9, the deconstructed material X generated by the dismantling is reduced, the filling rate of the disassembled material X in the torus chamber 9 is increased, and the torus chamber 9 The pressure on the inner floor space can be reduced.
For this reason, according to this embodiment, the pressure of the floor space in the torus chamber 9 by the dismantled object X can be reduced, and the preceding dismantling in the torus chamber 9 and the flow line 20 can be ensured.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 7 is a diagram showing a work flow of the incomplete dismantling method according to the second embodiment of the present invention. 8 and 9 are schematic diagrams for explaining the work process of the incomplete dismantling method in the second embodiment of the present invention. FIG. 9B is a side view of the torus chamber 9 shown in FIG.
The incomplete dismantling method of the second embodiment is one before the pool water P of the suppression chamber 5 is transferred. Also in this method, first, as in the above-described embodiment, the work space in the torus chamber 9 is maintained and the dismantling materials and equipment are carried in (step S11). By this step S11, the inside of the torus chamber 9 is maintained as shown in FIG.

  In this method, next, a partial decomposition of the downcomer 8 and the vent header 7 is performed (step S12). This step S12 partially disassembles the structure in the torus chamber 9 (first step), and the dismantled product X generated by the disassembly is surrounded by the housing of the suppression chamber 5 in the torus chamber 9. The space is stored using at least a part of the space s2 (second step). As shown in FIG. 8 (b), the suppression chamber 5 holds the pool water P in the space s2 surrounded by the casing, and the dismantled product X partially decomposed here is submerged in the pool water P. Store temporarily.

  Next, the part to be cut of the suppression chamber 5 is reinforced (step S13). This step S13 reinforces the housing as necessary so as not to buckle due to the weight of the pool water P because the structural strength may be reduced if the upper portion 5a of the suppression chamber 5 is disassembled in a later process. is there. For example, as shown in FIG. 9A, the reinforcing member 32a is assembled in a truss shape and reinforced so as to support the inside of the suppression chamber 5. Further, as shown in FIG. 9B, a reinforcing material 32b is stretched in a wire shape on the ceiling of the torus chamber 9 so as to open the opening of the suppression chamber 5, and is reinforced.

  Next, partial cutting of the upper portion 5a of the suppression chamber 5 and temporary placement of the cut piece on the floor or the like are performed (step S14). When the upper part 5a of the suppression chamber 5 is disassembled, as shown in FIG. 9A, the lower part 5b of the suppression chamber 5 remains, and the suppression chamber 5 supported by the support legs 19 becomes self-supporting. Thus, by leaving the lower part 5b of the suppression chamber 5, dismantling can be performed while maintaining the function of holding the pool water P. The dismantled product X, which is a cut piece, is temporarily placed under the lower portion 5b of the suppression chamber 5, as shown in FIG.

  Next, the floor board 33 is installed in the removal part of the suppression chamber 5, and the floor surface is reinforced (step S15). As shown in FIG. 9 (b), this step S15 is a floor plate for forming a temporary storage space R for equipment for temporarily storing water treatment equipment for treating pool water P, ion-exchange resin for desalination, and the like. 33 is installed. The weight of the floor plate 33 and the floor load of the equipment installed on the floor surface are supported by raising a column from the floor surface in the torus chamber 9 as necessary.

  Finally, a guide 34 or the like is installed as a breakwater when the pool water P swells, is maintained as a temporary storage place, and stores materials and equipment (step S16). In order to dismantle the suppression chamber 5, the pool water P must be discarded, but the pool water P contains a rust preventive such as hexavalent chromium and needs to be rendered harmless to the environmental standard level. In this step S16, a place where the equipment for water treatment is installed is prepared, and the detoxification treatment is performed while circulating the pool water P.

  As described above, according to this incomplete dismantling method, the dismantled product X generated by the dismantling is obtained by partially dismantling the structure in the torus chamber 9 including the suppression chamber 5 instead of dismantling all at once. It is possible to reduce the pressure on the floor space in the torus chamber 9. Further, by storing the demolished product X in the space s2 surrounded by the casing of the suppression chamber 5, which is the largest structure in the torus chamber 9, the filling rate of the demolished product X in the torus chamber 9 is increased, and the torus The pressure on the floor space in the chamber 9 can be reduced.

  Specifically, as shown in FIG. 8B, the dismantled product X is submerged in the pool water P of the suppression chamber 5, and the dismantled product X is stored in a space surrounded by the casing of the suppression chamber 5. The filling rate of the dismantled product X in the torus chamber 9 can be increased, and the pressure on the floor space in the torus chamber 9 can be reduced.

  Further, in this incomplete dismantling method, the upper part 5a of the suppression chamber 5 is dismantled while maintaining the holding function of the pool water P while leaving the lower part 5b of the suppression chamber 5. If the upper portion 5a of the suppression chamber 5 is disassembled, the structural strength may be lowered. Therefore, as shown in FIG. 9, the housing is reinforced so as not to buckle. As a result, the dismantled product X is reduced without disassembling the lower portion 5b of the suppression chamber 5 to reduce the pressure on the floor space in the torus chamber 9, and the pool water P is retained. The pretreatment for disposal can be performed in parallel with the dismantling of the structure in the torus chamber 9.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 10 is a diagram showing a work flow of the incomplete dismantling method according to the third embodiment of the present invention. FIGS. 11-21 is a schematic diagram for demonstrating the work process of the incomplete dismantling method in 3rd Embodiment of this invention.
Unlike the above-mentioned embodiment, the third embodiment is a process-complete incomplete dismantling method, and adopts a scrap yard method in which a dismantled product X generated by dismantling is stored without being stored in a container.

  In this method, first, the upper portion 5a of the suppression chamber 5, the vent pipe 6, the vent header 7 and the like are disassembled and temporarily placed (step S21). As shown in FIG. 11, the torus chamber 9 has an annular area K that accommodates the suppression chamber 5, and step S <b> 21 is for dismantling X generated in the area (partial area) indicated by reference numeral K <b> 2. It is temporarily placed in the area (other area) indicated by reference numeral K1. As shown in FIG. 12 (a), a rail 40 and a lifting machine 41 are provided in the area indicated by reference numeral K1, and are generated not only in the dismantled product X generated in the area but also in the area indicated by reference numeral K2. The dismantled product X is also stored (temporarily placed) on the suppression chamber 5. Thereby, as shown in FIG.12 (b), the area shown with the code | symbol K2 is not squeezed by the demolition thing X, but a space is ensured.

  Next, the lower part 5b of the suppression chamber 5 is disassembled and temporarily placed (step S22). In step S22, as shown in FIG. 13, the dismantled product X generated in the area indicated by the symbol K4 (partial area) is temporarily placed in the area indicated by the symbol K3 (other areas). The lower portion 5b of the suppression chamber 5 is disassembled in the area indicated by reference numeral K4. In the area indicated by reference numeral K3, as shown in FIG. 14A, the dismantled product X generated in the area indicated by reference numeral K4 is stored (temporarily placed) on the suppression chamber 5. Thereby, as shown in FIG.14 (b), the area shown with the code | symbol K4 disassembles the upper part 5a and the lower part 5b of the suppression chamber 5, and a space is ensured.

  Next, the partition wall Y1 on one side of the scrap yard Y is installed (step S23). As shown in FIG. 15, the step S23 includes an area indicated by reference numeral K4 in which the upper portion 5a and the lower portion 5b of the suppression chamber 5 are disassembled, and an area indicated by reference numeral K1 in which the lower portion 5b of the suppression chamber 5 and the dismantled object X remain. A partition wall Y1 on one side of the scrap yard Y is installed at the boundary (next to the communication port 18 communicating with the main steam tunnel). As shown in FIG. 16, the partition wall Y1 of the scrap yard Y is provided with at least a suppression chamber 5 for raising the plate member 50 to a predetermined height (in order to increase the filling rate) while supporting both sides of the plate member 50 with the support members 51. To build up.

  Next, the dismantling material X of the lower part 5b of the suppression chamber 5 is moved to the scrap yard Y and shredded (step S24). In step S24, as shown in FIG. 17, the dismantled object X generated in the area (partial area) indicated by reference numeral K3 and the stored dismantled object X are indicated by reference numeral K6 through the area indicated by reference numeral K5. Move to an area (another area). An area indicated by reference sign K5 is an area where the dismantled object X is shredded. In this area, after the dismantled object X stored in the area indicated by the symbol K3 is shredded and moved, the work of dismantling and shredding the remaining lower part 5b of the suppression chamber 5 as shown in FIG. Done. As shown in FIG. 18B, the area denoted by reference numeral K6 is an area for storing the dismantled object X generated in the area indicated by reference numeral K5 and other areas, and temporarily stores the dismantled object X from the partition Y1 side. To go.

  Next, the lower part 5b of the suppression chamber 5 is disassembled and temporarily placed in the scrap yard Y (step S25). In step S25, as shown in FIG. 19, the partition Y2 on the other side of the scrap yard Y is installed, the demolished object X is moved to the area indicated by the symbol K6 surrounded by the partition Y1 and the partition Y2, and the other areas The disassembly of the lower part 5b of the suppression chamber 5 is sequentially advanced. First, the dismantled object X stored on the lower portion 5b of the suppression chamber 5 is moved from the area indicated by reference numeral K1 (see FIG. 20A). Next, in the area indicated by reference numeral K7, the lower portion 5b of the suppression chamber 5 is disassembled, and the dismantled product X is moved to the area indicated by reference numeral K5 (see FIG. 20B). The dismantled product X is shredded in an area indicated by a symbol K5 and accommodated in an area indicated by a symbol K6.

  Finally, the container is carried in and the dismantled item X is stored and carried out (step S26). In step S26, as shown in FIG. 21, one batch of containers is carried into the area indicated by reference numeral K8, the scraps X of the scrap yard Y are stored in the containers, and the scraps X stored in the containers are unloaded. Is. Note that this carrying-in, storing, and carrying-out is a batch process and is repeated sequentially. The container can be carried in and the dismantled article X stored in the container can be carried out from the appendage 10 through the communication port 16 or from the main steam tunnel through the communication port 18.

As described above, according to this incomplete dismantling method, a part of the structure of the annular area K of the torus chamber 9 is dismantled, and the dismantled object X is temporarily placed in another area to dismantle the area. A scrap yard Y is provided, and the storage work for storing the dismantled product X in the container is postponed, and then the carry-out operation for carrying out the dismantled product X is made to be just-in-time. Thereby, the storage number (container storage number) of the demolition thing X in the torus chamber 9 can be reduced, and the compression of the floor space in the torus chamber 9 can be reduced.
Further, in this incomplete dismantling method, the upper portion 5a of the suppression chamber 5 is disassembled while maintaining the self-supporting function by the support legs 19, and the dismantled product X is stored on the saddle-shaped suppression chamber 5. Thereby, while reducing the disassembled object X without disassembling the lower part 5b of the suppression chamber 5, the filling rate of the disassembled object X in the torus chamber 9 is increased, and the pressure on the floor space in the torus chamber 9 is reduced. be able to.

FIG. 22 is a diagram for comparing the work flows of the incomplete dismantling method and the conventional method in the third embodiment of the present invention. FIG. 22A shows the incomplete disassembly method of the third embodiment, and FIG. 22B shows the conventional method.
As shown in FIG. 22 (b), in the conventional method, the inside of the torus chamber 9 is roughly disassembled, the dismantled product X is shredded, the shredded product X is stored in a container, and temporarily stored. And when this cycle is repeated and the final disposal place of the dismantled object X is decided, the container which was temporarily stored is carried out. Therefore, when the time to carry out the dismantled product X is delayed, the floor space of the torus chamber 9 may be compressed by the container.

  On the other hand, as shown in FIG. 22 (a), in this method (scrap yard method), the inside of the torus chamber 9 is roughly disassembled, the dismantled product X is shredded, and the shredded dismantled product X is turned into a scrap yard Y. Temporary storage. When the final disposal site for the dismantled product X is determined, the dismantled product X that has been temporarily stored is stored in a container and is carried out. As described above, in this method, by providing the scrap yard Y, the work of storing the dismantled object X in the container can be made just-in-time to the work of carrying out the dismantled object X. (Number of containers stored) can be reduced and space can be secured. Therefore, even when the time for carrying out the dismantled object X is delayed, the floor space in the torus chamber 9 is not compressed.

  Further, according to this method, by providing the scrap yard Y, it becomes easy to secure an empty space in the torus chamber 9 as described above. For this reason, the work space can be easily divided by dismantling and container storage, and the work can be closed in the torus chamber 9. Further, by providing the scrap yard Y, the dismantled product X can be sorted and stored, so that it is possible to reduce the empty container and its place. Moreover, in the operation of storing the dismantled object X, since the dismantled object X that has already been shredded is handled, the filling rate of the container can be increased, and the dismantled object X can be easily stored according to the degree of contamination. . In addition, it becomes possible to eliminate the use of custom containers for multi-stacking.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  2 ... Reactor containment vessel, 5 ... Suppression chamber, 5a ... Upper part, 5b ... Lower part, 6 ... Vent pipe, 9 ... Torus chamber, 10 ... Appendix, 19 ... Support leg, 20 ... Flow line, 32a ... Reinforcement material, 32b ... reinforcing material, K ... annular area, P ... pool water, s1 ... space, s2 ... space, X ... demolition, Y ... scrap yard

Claims (7)

A method for removing a nuclear reactor having a torus chamber containing a suppression chamber communicating with a containment vessel and a vent pipe,
A first step of partially disassembling a structure in the torus chamber including the suppression chamber;
Storing the dismantled product generated by the dismantling using at least a part of the space surrounded by the housing of the suppression chamber or the space surrounded by the housing in the torus chamber, and Reactor removal method characterized by that. The suppression chamber is self-supporting via a support leg in the torus chamber,
The first step includes a step of partially disassembling a lower portion of the suppression chamber,
The said 2nd process includes the process of storing the said dismantled thing in the space under the said suppression chamber which becomes self-supporting in the shape of a roof via the said support leg by the said dismantling. Reactor removal method described. The support legs are provided in pairs so as to face each other in the width direction of the suppression chamber,
The first step includes a step of partially disassembling at least one of the support legs provided as a pair to increase a distance between the support legs in the width direction. The reactor removal method according to claim 2. The suppression chamber holds pool water in a space surrounded by the casing,
The method for removing a nuclear reactor according to claim 1, wherein the second step includes a step of storing the dismantled product in the pool water. The first step includes
Partially disassembling the upper portion of the suppression chamber holding the pool water;
The method for removing a nuclear reactor according to claim 4, further comprising a step of reinforcing the casing so as not to buckle due to a weight of the pool water by partially disassembling the upper portion of the suppression chamber. . The suppression chamber is self-supporting via a support leg in the torus chamber,
The first step includes a step of partially disassembling the upper portion of the suppression chamber;
The said 2nd process includes the process of storing the said dismantled thing on the above-mentioned suppression chamber which becomes self-standing in the shape of a bowl via the above-mentioned support leg by the above-mentioned dismantling, characterized by things. 5. The reactor removal method according to any one of 5 above. The torus chamber has an annular area for accommodating the suppression chamber;
The first step includes a step of dismantling the structure of a part of the area in the annular area,
The second step includes
Temporarily placing the dismantled part of the partial area in another area;
The method for removing a nuclear reactor according to any one of claims 1 to 6, further comprising a step of providing a scrap yard for storing the dismantled material in the partial area.

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