JP2013181921A - Method for dismantling radioactive contaminated facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for dismantling a radioactive contaminated facility for dismantling the facility in short time without a worker entering a dismantlement area and securing safety against exposure.SOLUTION: In a method for dismantling a radioactive contaminated facility for newly installing a shelter 14 on the outer periphery of a building 12 of the radioactive contaminated facility so as to cover the building 12, installing lifting means 16 in the shelter 14, and performing a series of works of dismantlement, decontamination, shredding, container storage of a skeleton of the building 12 in the shelter 14, the skeleton of the building is segmented like a block by a remote operation to be sequentially dismantled downward from an upper part of the building 12, the segmented block-like skeleton of the building is lifted by the lifting means 16 and carried to a work area 18 with a degree of contamination lower than that of the building 12, which is provided in the shelter 14, to be decontaminated in the work area 18.

Description

  The present invention relates to a method for dismantling radioactively contaminated facilities such as radioactively contaminated nuclear power generation facilities and nuclear fuel facilities.

  In the dismantling method associated with the conventional decommissioning plan for nuclear power generation facilities, removal of equipment and piping installed in the building is given priority in order to make the power plant building the final boundary. That is, as shown in the flowchart of FIG. 18, after the removal of the equipment and piping is completed, the radioactively contaminated concrete surface is decontaminated by the suspension method, and the management area is released through the survey work. Finally, the building is demolished sequentially from top to bottom in the same way as ordinary buildings.

  For example, Patent Documents 1 to 3 are known as conventional techniques related to a dismantling method for a nuclear power generation facility or the like. Here, Patent Document 1 relates to the dismantling of nuclear facilities, after removing radioactive material on the inner wall surface of the reactor containment vessel, dismantling it to a predetermined size, storing it in the vessel, and transporting it to the turbine building through the tunnel. The decontamination work is performed by chopping the dismantled material in the container in the turbine building.

  Patent Document 2 relates to the dismantling of the reactor building, and the building is moved upward from below by repeating the step of dismantling a part of the building on the lower floor and the step of lifting down the building above it. Will be dismantled sequentially.

  Patent Document 3 relates to the dismantling of a boiler building. After a part of the building is lifted and supported by lifting means to separate a part of the building from the remaining part, the part of the building is moved to the lower part. The part of the building is sequentially dismantled sequentially from the bottom to the top by repeating the step of dismantling from the top and the step of lowering the part of the building by the lifting means.

JP 2010-8091 A JP 11-270152 A Japanese Patent Laid-Open No. 10-46838

  By the way, in facilities such as the Fukushima Daiichi nuclear power plant that caused the radioactive leak accident, equipment and piping throughout the building and the surface of the enclosure are contaminated with FP (fission products) and U (uranium). The building does not function as the final boundary. In this case, it is difficult to apply the procedure of dismantling the conventional equipment and piping in advance and then dismantling the building because it is difficult to ensure the safety of workers against exposure.

  The present invention has been made in view of the above, and it is possible to dismantle a facility in a short period of time without an operator entering the dismantling area, and to dismantle a radioactive contamination facility capable of ensuring safety against exposure. It aims to provide a method.

  In order to solve the above-described problems and achieve the object, the method for dismantling a radioactively contaminated facility according to claim 1 of the present invention provides a new roof on the outer periphery so as to cover the building of the radioactively contaminated facility. At the same time, a lifting means is installed in the shed, and the decontamination method of the radioactive contamination facility in which a series of operations of demolition, decontamination, shredding, and container storage of the building enclosure is performed in the shed. The building housing is cut into a block shape by remote operation, and the building is sequentially disassembled from the upper side to the lower side of the building, and the cut block building building is lifted by the lifting means. The degree of contamination provided in the building is transported to a work area lower than the building and decontaminated in this work area.

  In addition, the method for dismantling a radioactive contamination facility according to claim 2 of the present invention is characterized in that, in claim 1 described above, the building housing and the existing equipment and piping are cut out integrally with the building housing. And

  A method for dismantling a radioactive contamination facility according to claim 3 of the present invention is the method of disassembling a radioactive contamination facility according to claim 1 or 2, wherein a perforation means provided on the slab forming the building enclosure is remotely operated to penetrate the slab. A columnar support having automatic extension means and upper widening means is inserted from above the through hole, and is disposed between the lower surface of the slab and the upper surface of the lower slab, and the slab is inserted through the support work. After the load is temporarily supported by the slab on the lower floor, the slab is cut out.

  According to a fourth aspect of the present invention, there is provided a method for dismantling a radioactive contamination facility according to the third aspect, wherein the piercing means is remotely operated to provide a through hole in the slab, and the lower widening from above the through hole. A hanging jig provided with means is inserted and attached to the slab, and the cut out slab is lifted by the lifting means through the hanging jig.

  According to the present invention, a new shed is installed on the outer periphery so as to cover the building of the radioactively contaminated facility, and a lifting means is installed in the shed, and the building skeleton in the shed. Is a method of dismantling a radioactive contamination facility that performs a series of operations of dismantling, decontamination, shredding, and container storage, by cutting out the building housing into a block shape by remote control, from the top to the bottom of the building Sequentially dismantled, the block-shaped building frame that has been cut out is lifted by the lifting means, transported to a work area with a lower degree of contamination than the building, and decontaminated in this work area Since it did in this way, an operator can dismantle the building of a facility in a short period of time without entering the dismantling area of the building frame, and there is an effect that it is possible to ensure safety against the exposure of the worker.

FIG. 1 is a front sectional view of a facility which is a target of a method for dismantling a radioactively contaminated facility according to the present invention. FIG. 2 is a plan view of a facility that is a target of the method for dismantling a radioactively contaminated facility according to the present invention. FIG. 3 is a schematic view showing a building dismantling procedure according to the dismantling method of the radioactive contamination facility according to the present invention. FIG. 4 is a diagram showing a procedure 1 for integrally cutting a floor and equipment / piping. FIG. 5 is a diagram showing a procedure 2 for cutting out the floor and the equipment / pipings integrally. FIG. 6 is a diagram illustrating a procedure 3 for integrally cutting the floor and the equipment / piping. FIG. 7 is a diagram showing a procedure 4 for cutting out the floor and the equipment / pipings integrally. FIG. 8 is a flowchart illustrating an example of a processing procedure after the housing is cut out. FIG. 9 is a plan view showing the layout of the work area. FIG. 10 is a diagram showing a procedure 1 for cutting out a building frame alone. FIG. 11 is a diagram illustrating a procedure 2 for cutting out a building frame alone. FIG. 12 is a diagram illustrating a procedure 3 for cutting out a building frame alone. FIG. 13 is a diagram illustrating a procedure 4 for cutting out a building frame alone. FIG. 14 is a flowchart illustrating an example of a processing procedure after the body is cut out. FIG. 15 is a diagram showing a through hole drilling process. FIG. 16 is a diagram showing a support installation process. FIG. 17 is a diagram illustrating a process of attaching the hanging jig. FIG. 18 is a schematic flowchart showing a dismantling procedure associated with a conventional nuclear power facility decommissioning plan.

  Embodiments of a method for dismantling a radioactive contamination facility according to the present invention will be described below in detail with reference to the drawings. In the following, we will explain an example of a nuclear power generation facility where the entire equipment and piping inside and outside the building and the surface are contaminated with FP (fission products) and U (uranium) due to a radioactive leak accident, etc. The invention is not limited to the examples.

  As shown in FIG. 1 and FIG. 2, the method for dismantling a radioactively contaminated facility according to the present invention newly installs a roof 14 on the outer periphery so as to cover the building 12 of the radioactively contaminated facility 10. An overhead crane 16 (lifting means) and a work area 18 having a pollution level lower than that of the building 12 are installed in the store 14, and the building housing is dismantled, decontaminated, shredded, and stored in the container 14 It is premised on a series of operations. In FIG. 1, a dotted line portion 2 is a ceiling portion of the building that has disappeared due to an explosion accident or the like.

  The roof 14 is a substantially rectangular parallelepiped structure having a plurality of steel columns 20, an SC wall (steel plate concrete structure wall) 22 that supports the steel columns 20, and a truss-structured ceiling roof 15. The building 12 is shielded from the outside by covering it with the object.

  The SC wall 22 is a wall structure in which concrete is filled between two steel plates, and the foundation is embedded below the ground surface GL. A ground improvement body 26 is constructed under the foundation of the SC wall 22, and a water blocking wall 24 is constructed in the outer periphery underground of the roof 14.

  The overhead crane 16 under the ceiling roof 15 is configured to be able to travel in the roof 14 along rails 21 provided on the steel column 20.

  As a method of dismantling the building 12, as shown in FIGS. 3 (1) to (5), the dismantling and removal are sequentially performed from the upper side to the lower side of the building frame using the overhead crane 16 in the upper building 14.

  More specifically, concrete such as a floor, a beam, and a wall constituting the building frame is cut out in a block shape by remote operation according to a procedure described later. Then, the cut-out block-shaped building frame is lifted by the overhead crane 16 and transported to the work area 18 in the roof 14, and post-process work such as decontamination work is performed in the work area 18.

(Procedure for cutting out the building frame)
Next, regarding the procedure of cutting concrete such as the floor that forms the building frame, when cutting the floor and equipment / piping together, and when cutting out the building frame from which equipment / piping has already been removed. Separately described.

[When cutting the floor and equipment / piping together]
First, a case where the floor and the equipment and piping are cut out integrally with the equipment and piping attached to the floor will be described with reference to FIGS. In addition, in each figure of FIGS. 4-7, (1) is a plane sectional view, (2) is a front sectional view.

  As shown in FIG. 4, piping 30 and rails 34 are attached to the lower surface side of a floor 36 (slab) having beams 38. A tank 28 (equipment) is installed on the floor 37 of the lower floor, and piping 32 is attached to the side surface of the wall 40. First, a plurality of openings 42 for cutting the piping 30 and the rail 34 are opened in the floor 36. The opening 42 can be drilled by remotely operating a core boring device, a wire saw device, a diamond blade device, or the like (not shown) disposed on the floor 36.

  Next, as shown in FIG. 5, the piping 30 and the rail 34 below the floor 36 are cut through the openings 42 at the cut surfaces 30a and 34a.

  Next, as shown in FIG. 6, anchor bolts 44 such as epoxy anchors are attached to a plurality of locations on the floor 36 and are lifted by the overhead crane 16 via the anchor bolts 44. Next, the floor 36 is cut by remotely operating a wire saw device (not shown) with the boundary portion 36a between the floor 36 and the wall 40 and the beam 38 as a cutting position. Then, the block-shaped floor 36 cut out together with the piping 30 and the rail 34 is lifted by the overhead crane 16 and removed. Similarly, after cutting the beam 38, it is lifted and removed.

  Finally, as shown in FIG. 7, the pipes 32 installed on the tank 28 and the wall 40 are lifted and removed in the state of the blue ceiling from which the floor 36 and the beam 38 have been removed. Thereafter, the wall 40 is cut and lifted and removed in the same manner as described above.

  Thus, according to the present invention, equipment and piping installed under the floor can be safely removed from the floor without an operator entering the room. In addition, the equipment and piping installed on the floor and on the wall can be dismantled with excellent remoteness and liftability in a blue ceiling without a ceiling slab (floor on the upper floor).

  The removed large block floor 36 (slab), beams 38, walls 40, tanks 28, pipes 30, 32, rails 34, etc. removed are transported to the work area 18 by the overhead crane 16 and then decontaminated. Shredded and containerized. The subsequent processing procedure in the work area 18 is performed through steps S1, S2, and S3 as illustrated in FIG. In this way, according to the present invention, a frame such as a floor is cut into a large block shape, and decontamination, shredding, container storage, etc. are performed in a safe work area of the building outdoor part, so that parallel work is possible. The construction period can be shortened.

Here, in the processing procedure of FIG. 8, the following (1) to (5) are preconditions.
(1) It is assumed that concrete such as slab (floor) in the part to be dismantled has not been activated, and if FP and U adhering to the surface are decontaminated, it will become CL (thing that does not need to be treated as radioactive material). .
(2) With the equipment / piping attached to the slab (floor), the slab (floor) and the equipment / piping are integrally cut out, and the equipment / piping is removed in the indoor work area.
(3) Concrete such as slab (floor) cut out in blocks should be shredded after surface decontamination to avoid cross-contamination during shredding.
(4) The suspended pieces and powder on the concrete surface can be recovered almost 100% by local dust collection and ventilation within the suspended area.
(5) In order to avoid cross-contamination due to permeation at the time of the fishing work, the liquid is not used.

  In step S1 of FIG. 8, the slab (floor) is cut into blocks, and then lifted by an overhead crane, moved to a work space (work area) in a container (shed), placed on a gantry, Piping is removed from the floor. The removed piping is processed by the process of step S3 described later.

  The concrete from which the pipes have been removed is lowered from the mount onto the ground work floor. Subsequently, a barrier is installed here, and the surface of the concrete surface is suspended by a lifting device such as a spiky hammer. Flip the front and back sides of the backside surface. In addition, the powder produced by the suspension decontamination of the concrete surface is processed by the step S2 described later.

  The concrete with the surface moved is moved to a shredding area and shredded into a storage shape for a CL verification container, and then stored in a CL verification container for CL verification. After this, after recycling processing such as crushing and particle size adjustment, it is reused for roadbed materials.

  Step S2 relates to processing of powders such as FP and U generated by decontamination of the concrete surface. Powders such as FP and U are stored in a disposal container, filled with mortar, temporarily measured by measuring the surface dose, and finally buried.

  Step S3 relates to the decontamination processing of the contaminated piping. After decontamination of the contaminated piping by a physical method such as blasting or a chemical method, the processing is divided into steps S31 and S32. In step S31, FP, U powder and sludge are stored in a disposal container, filled with mortar and sand, surface dose is measured, temporarily stored, and finally buried.

  In step S32, the metal base material is shredded by gas cutting or the like, and the radioactive level is relatively low (L2), the radioactive level is extremely low (L3), or the radioactive material is not required to be handled (CL) It is divided and processed. About L2, after storing a container, it transfers to step S31 and is filled with mortar and sand, then the surface dose is measured and temporarily stored, and finally buried. About L3, it accommodates in a flexible container (flexible container bag), and is disposed of in an underground trench. The CL is stored in a verification container and reused after verification.

  As shown in FIG. 9, the work area 18 includes a fishing area 18a, a shredding area 18b, a container storage / filling area 18c, a piping removal area 18d, a piping shredding area 18e, a metal container storing / filling area 18f. Consists of. In addition to the overhead crane 16, a portal crane 18g dedicated to the work area is provided in the work area 18. Further, an area 46 for producing filling mortar and the like is provided on the site outside the roof 14.

  As described above, according to the present invention, since concrete is cut out from a building in a large block shape, it is decontaminated and then shredded, so that occurrence of cross contamination is suppressed. Thereby, the contaminated waste of FP and U can be reduced.

[When cutting out the building frame alone]
Next, a case where a building frame (floor, beam, wall) is cut out alone with the devices and piping already removed will be described with reference to FIGS. In addition, in each figure of FIGS. 10-12, (1) is a plane sectional view, (2) is a front sectional view.

  First, as shown in FIG. 10, anchor bolts 44 such as epoxy anchors are attached to a plurality of locations on the floor 36 and are lifted by the overhead crane 16 via the anchor bolts 44. Next, the floor 36 is cut by remotely operating a wire saw device (not shown) with the boundary portion 36a between the floor 36 and the wall 40 and the beam 38 as a cutting position. Then, the block-shaped floor 36 cut out is lifted by the overhead crane 16 and removed.

  Similarly, as shown in FIG. 11, the beam 38 is lifted by the overhead crane 16, and the front and rear end portions 38 a are cut at the cutting position, and then lifted and removed.

  Next, as shown in FIG. 12, the wall 40 is lifted by the overhead crane 16, and the lower end and the side end 40a are cut at the cutting position, and then lifted and removed.

  The removed block-like floor 36 (slab), beam 38, and wall 40 are respectively transported to the suspension area 18a of the work area 18 by the overhead crane 16, and the concrete surface thereof is suspended by a suspension device 48 such as a spiky hammer. Subsequent processing procedures in this area are performed through steps S1 and S2, as illustrated in FIG.

Here, in the processing procedure of FIG. 14, the following (1) to (4) are preconditions.
(1) It is assumed that concrete such as slab (floor) in the part to be dismantled has not been activated, and if FP and U adhering to the surface are decontaminated, it will become CL (thing that does not need to be treated as radioactive material). .
(2) Concrete such as slab (floor) cut out in blocks should be shredded after surface decontamination to avoid cross-contamination during shredding.
(3) The suspended pieces and powder on the concrete surface can be recovered almost 100% by local dust collection and ventilation within the suspended area.
(4) In order to avoid cross-contamination due to permeation during the suspending operation, suspending using liquid is not performed.

  In step S1 of FIG. 14, after cutting the slab (floor) into blocks, the slab is lifted by an overhead crane, moved to a work space (work area) in a container (shed), and a barrier is installed here. The surface of the concrete is suspended by a lifting device such as a spiky hammer. Flip the front and back sides of the backside surface. In addition, the powder produced by the suspension decontamination of the concrete surface is processed by the step S2 described later.

  The concrete with the surface moved is moved to a shredding area and shredded into a storage shape for a CL verification container, and then stored in a CL verification container for CL verification. After this, after recycling processing such as crushing and particle size adjustment, it is reused for roadbed materials.

  Step S2 relates to processing of powders such as FP and U generated by decontamination of the concrete surface. Powders such as FP and U are stored in a disposal container, filled with mortar, temporarily measured by measuring the surface dose, and finally buried.

(Support and hanging jig when cutting out the building frame)
Next, the structure and operation of the support and suspension jig used when cutting out the building frame will be described with reference to FIGS. In addition, in each figure of FIGS. 15-17, (1) is a top view, (2) is front sectional drawing.

  As shown in FIG. 15, the core boring device 50 (perforating means) is disposed on the floor 36 (slab), and a plurality of through holes 52 are provided on the outer peripheral side of the floor 36. The through holes 52 are for support installation, and the diameter thereof may be about φ200 mm and the installation pitch may be about 2 m, for example. The core boring device 50 is remotely operated from outside the building 12.

  Next, as shown in FIGS. 16 (1) and (2), a columnar support 54 is inserted from above the through hole 52 with the overhead crane 16 and placed between the lower surface of the floor 36 and the upper surface of the floor 37 of the lower floor. To do. The diameter of the support work 54 may be, for example, about φ150 mm, which is smaller than the through hole 52.

  Here, the support work 54 is provided with an automatic extension means (not shown) that automatically extends its length by a remote operation and an upper widening means, and is automatically fixed between the floors 36 and 37. As shown in the enlarged view of the main part of FIG. 16 (3), the upper widening means includes a shaft portion 54b provided on the rod-shaped portion 54a and a right-triangular lock piece 54c whose vertex is rotatably attached to the shaft portion 54b. The lock piece 54c opens when passing through the through hole 52 and comes into contact with the lower surface of the floor 36. In addition, you may comprise this upper widening means with other means, such as a clasp in an umbrella. Further, a protrusion 54 d having a diameter larger than that of the through hole 52 is provided at the upper end of the support work 54 so that the support work 54 does not enter the through hole 52. By arranging a plurality of support works 54 in the vicinity of the wall 40, the load on the floor 36 is temporarily transmitted to the floor 37 on the lower floor via the support work 54.

  Next, as shown in FIGS. 17 (1) and (2), a plurality of through holes 56 are provided on the center side of the floor 36 (slab). The through hole 56 is for installing a lifting jig, and the diameter thereof may be about φ100 mm, for example. The through hole 56 may be provided at the same time as the through hole 52. Then, the suspension jig 58 is inserted into the through hole 56 using the overhead crane 16 and attached to the floor 36.

  Here, as shown in the front view of FIG. 17 (3) and the side view of FIG. 17 (4), the suspension jig 58 is provided on the barrel portion 58a and the lower portion of the barrel portion 58a and rotates around the shaft 58d. And a long hole 58c for retracting and retracting the portion 58b. A hook engaging hole 58e for an overhead crane and a protrusion 58f are provided on the upper portion of the body portion 58a. The jaw portion 58b functions as a lower widening means for widening the lower portion of the hanging jig 58.

  FIG. 17 (3) shows a state in which the jaw portion 58b rotates and protrudes from the long hole 58c. If it is configured using a spring or the like so as to balance in this state at normal time, when the hanging jig 58 is inserted into the through hole 56 with the jaw portion 58b stored in the elongated hole 58c, the jaw portion 58b is automatically Thus, the lower part of the hanging jig 58 is widened by rotating and projecting. Thereby, it becomes the state which the jaw part 58b contact | abutted to the floor 36 lower surface, and can receive a floor load physically. For this reason, there is no possibility of pulling out unlike the case where an anchor is used.

  Subsequently, as shown in FIGS. 17 (1) and 17 (2), the floor 36 is cut by remotely operating a wire saw device (not shown) with the boundary portion 36a between the floor 36 and the wall 40 and the beam 38 as a cutting position. To do. The cut out floor 36 is lifted and transported by the overhead crane 16 through the hanging jig 58. By such a procedure, the floor 36 (slab) can be removed without occupying the overhead crane 16 as a supporting work.

  In the present invention, the building is intended for a building where workers cannot stay in the dismantling area for a long time or is difficult to access, and basically all work performed in the building is performed by remote control of a remote device. Here, when the remote device is not employed, it is necessary to leave the apparatus for a very long time until the air dose in the dismantling area is lowered, which is not practical. In addition, decontamination work on the housing surface, equipment surface, and inside is required to allow people to approach, but if this decontamination work is not performed by a remote device, the construction period may be prolonged and the cost may be enormous. There is a problem that there is.

  As described above, according to the present invention, a new shed is installed on the outer periphery so as to cover the building of the radioactively contaminated facility, and a lifting means is installed in the shed. A decontamination method of a radioactive contamination facility that performs a series of operations of dismantling, decontamination, shredding, and container storage of the building enclosure, cutting the building enclosure into a block shape by remote operation, Dismantled sequentially from the top to the bottom, the cut block-shaped building frame is lifted by the lifting means and transported to a work area having a lower pollution level than the building, Since decontamination is performed in the work area, the facility building can be dismantled in a short period of time without the worker entering the building demolition area, and safety against exposure of the worker can be ensured.

  As described above, the method for dismantling a radioactive contamination facility according to the present invention is useful for dismantling the facility in a short period of time without the worker entering the dismantling area. Suitable for securing.

10 Nuclear power generation facilities (radioactive contamination facilities)
12 building 14 roof 16 overhead crane (lifting means)
18 Work area 20 Steel column 22 SC wall 24 Water blocking wall 26 Ground improvement body 28 Tank (equipment)
30, 32 Piping 34 Rail 36 Floor (Building frame, slab)
37 Lower floor (lower slab)
38 Liang (building enclosure)
40 walls (building enclosure)
42 Opening 44 Anchor bolt 46 Area 48 Lifting device 50 Core boring device (drilling means)
52, 56 Through hole 54 Support work 54c Lock piece (upper widening means)
58 Suspension jig 58b Jaw part (lower widening means)
GL Ground surface

Claims (4)

In addition to installing a new shed on the outer periphery to cover the building of the radioactively contaminated facility, a lifting means is installed in the shed, and the building housing is dismantled, decontaminated, A method of dismantling a radioactive contamination facility that performs a series of operations such as shredding and container storage,
The building housing was cut out into a block shape by remote operation, and was sequentially disassembled from the top to the bottom of the building, and the cut-out building housing was lifted by the lifting means and provided in the upper indoor area. A method for dismantling a radioactively contaminated facility, characterized in that it is transported to a work area having a pollution level lower than that of the building and decontaminated in this work area.   The method for dismantling a radioactive contamination facility according to claim 1, wherein the building housing and the equipment and piping existing in the building housing are cut out integrally.   A piercing means provided on the slab constituting the building frame is remotely operated to provide a through hole in the slab, and a columnar supporter having an automatic extension means and an upper widening means is inserted from above the through hole to insert the slab. 2. It arrange | positions between a lower surface and the slab upper surface of a lower floor, The load of the said slab is temporarily supported by the slab of a lower floor via the said support work, The said slab is cut out, It is characterized by the above-mentioned. Or the dismantling method of the radioactive contamination facility of 2.   The piercing means is remotely operated to provide a through hole in the slab, a suspension jig having a lower widening means is inserted from above the penetration hole and attached to the slab, and the cut slab is attached to the suspension jig. The method for dismantling a radioactively contaminated facility according to claim 3, wherein the lifting is performed by the lifting means.

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