JP2014115159A - Method and device for decontamination processing of contaminated concrete mass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decontamination processing method which is effective and suitable for efficiently decontaminating a contaminated concrete mass contaminated by a radioactive substance and to provide a device for the decontamination processing method.SOLUTION: In a decontamination processing method, contaminated concrete masses 1 are input at an upstream side of a wire net 2 arranged in an inclined state and transferred from the upstream side to a downstream side of the wire net. While the contaminated concrete masses 1 are transferred, superficial portions of the contaminated concrete masses are ground and crushed through a collision between the contaminated concrete masses and contact between the same and the wire net. Pulverized powders and fragments generated through the collision and the contact are collected by allowing the same to fall through a mesh of the wire net. The contaminated concrete masses which are decontaminated with superficial portions thereof ground and crushed are collected at the downstream side of the wire net. A type of the wire net which can be suitably used in the decontamination processing method is: a flat type wire net 2A with oscillation applied thereto by an oscillation mechanism 3; a gutter type wire net with an almost U-shaped cross section which can be rocked from side to side; or a cylinder type wire net with a cylindrical shape which can be rotated.

Description

  The present invention relates to a method and an apparatus for performing decontamination treatment on a contaminated concrete block having a radioactive substance attached and permeated on its surface.

  In the event of an accident at a nuclear facility such as a nuclear power plant, or when dismantling or renewal work for those facilities, it is assumed that a large amount of concrete contaminated with radioactive materials will be generated.

Since radioactive materials adhere to and permeate the surface of such contaminated concrete, it is necessary to perform sufficient decontamination treatment in advance to safely dispose of the contaminated concrete. What is shown by patent document 1, 2 is proposed.
In Patent Document 1, decontamination water is ejected from a nozzle to a large decontamination product such as a large device or a floor surface / wall surface of a building, and ultrasonic vibration is applied to the water flow to perform decontamination processing by water washing. That's it.
Patent Document 2 discloses that a contaminated concrete structure such as a building frame is cut and removed by a disk blade.

JP-A-9-189799 JP 2007-10536 A

By the way, a huge amount of debris was generated in the Great East Japan Earthquake, and a large amount of rubble-like concrete lumps (so-called concrete galaxies) contaminated with radioactive materials are contained in such debris. An effective and appropriate decontamination method for lumps has not yet been established.
Of course, since the conventional decontamination methods proposed in Patent Documents 1 and 2 are applied to decontamination and demolition of a sound concrete structure, such methods are applied to contaminated concrete blocks. It cannot be applied as a decontamination method.

  In view of the above circumstances, an object of the present invention is to provide an effective and appropriate decontamination method for efficiently decontaminating a contaminated concrete block contaminated with a radioactive substance, and an apparatus therefor.

  The invention according to claim 1 is a method for decontamination of a contaminated concrete lump for performing decontamination treatment on a contaminated concrete lump on which radioactive substances adhere to and permeate the surface, and is inclined with respect to the horizontal. The contaminated concrete block to be decontaminated is placed on the upstream side of the wire mesh disposed in step S1 and the contaminated concrete block is transferred from the upstream side to the downstream side on the wire mesh. The surface layer of the contaminated concrete lump is ground and crushed by the collision of the lump and contact between the contaminated concrete lump and the wire mesh, and the ground powder and crushed pieces generated thereby are dropped and collected through the mesh of the wire mesh. In addition, the concrete block after decontamination in which the surface layer portion is ground and crushed is collected from the downstream side of the wire mesh.

  The invention described in claim 2 is a decontamination treatment apparatus for contaminated concrete lump for carrying out the decontamination processing method for contaminated concrete lump according to claim 1, wherein the wire mesh is constituted by a flat flat wire mesh, The flat wire mesh is configured to be able to vibrate in the vertical direction by a vibration mechanism.

  A third aspect of the invention is a decontamination treatment apparatus for a contaminated concrete lump for carrying out the decontamination treatment method for a contaminated concrete lump according to claim 1, wherein the wire mesh is formed by a saddle-shaped wire mesh having a substantially U-shaped cross section. In addition, the saddle-shaped wire mesh is configured to be rockable to the left and right with its axis as the center.

  Invention of Claim 4 is a decontamination processing apparatus of the contaminated concrete block for implementing the decontamination processing method of the contaminated concrete block of Claim 1, Comprising: The said wire mesh is comprised with a cylindrical cylindrical wire mesh. In addition, the cylindrical metal mesh is configured to be rotatable about its axis.

According to the present invention, only the contaminated concrete block is transferred from the upstream side to the downstream side on the wire mesh, and only the surface layer portion of the contaminated concrete block is removed as ground powder or crushed pieces during the transfer. It can be recovered by dropping it through a wire mesh.
Therefore, according to the present invention, only a small amount of pulverized powder and crushed pieces should be processed and disposed of as radioactive waste, and the concrete block after decontamination from which the surface layer portion has been removed is It is also possible to effectively use it as a resource, and from the above, it is possible to significantly reduce the labor and cost required for the decontamination process.

1A and 1B show a first embodiment of a decontamination processing apparatus of the present invention, in which FIG. 2 shows a second embodiment of the decontamination processing apparatus of the present invention, (a) is a diagram showing a saddle-shaped wire mesh, (b) is a side view showing an overall schematic configuration, (c) is a c- in (b). FIG. The 3rd Embodiment of the decontamination processing apparatus of this invention is shown, (a) is a figure which shows a cylindrical wire mesh, (b) is a side view which shows the whole schematic structure, (c) is c- in (b). FIG.

Hereinafter, an embodiment of a decontamination processing method and a decontamination processing apparatus for a contaminated concrete lump according to the present invention will be described.
The decontamination processing method of the present embodiment is directed to a contaminated concrete lump generated in the event of an accident in a nuclear facility such as a nuclear power plant, or a dismantling or renewal work for a nuclear facility. The decontamination treatment apparatus of the first to third embodiments shown in FIGS. 1 to 3 implements the method. It is suitable as an apparatus for the above.

  In this embodiment, the contaminated concrete block (concrete block contaminated with radioactive material) to be decontaminated is contaminated with radioactive material, but the radioactive material penetrates deep inside, and the whole Is not contaminated, and the radioactive material is simply attached to the surface or penetrates into a very shallow part (about several mm) of the surface layer. Therefore, in the decontamination treatment for such a contaminated concrete block, a sufficient decontamination effect can be obtained by removing the surface layer portion with a thickness of at least several millimeters.

  Based on the above knowledge, the decontamination processing method of the present embodiment is a wire mesh (in a slanted state relative to the horizontal) when performing decontamination processing on a contaminated concrete lump having radioactive material attached and permeated on its surface ( As the wire mesh, it is preferable to use a flat wire mesh, a saddle-shaped wire mesh, or a cylindrical wire mesh as will be described later). By transferring from the upstream side to the downstream side above, the surface layer part of the contaminated concrete block is ground and crushed by the collision of the contaminated concrete blocks and the contact between the contaminated concrete block and the wire mesh. The ground powder and crushed pieces generated by the above are dropped and collected through a wire mesh, and the surface layer is ground and crushed. The REITs mass is for recovering from the downstream side of the wire mesh.

  FIG. 1 shows a first embodiment of a decontamination processing apparatus for efficiently carrying out the above decontamination processing method, and (a) shows a wire mesh 2 (in the first embodiment, the main component). (B) is a side view showing the overall schematic configuration.

  In the decontamination processing apparatus of the first embodiment, the wire mesh 2 is constituted by a flat flat wire mesh 2A, and the flat wire mesh 2A is inclined at a predetermined inclination angle θ with respect to the horizontal as shown in FIG. 1 is a type of vibrating conveyor that is arranged in a state and can be vibrated in the vertical direction by a vibrating mechanism 3, and is a contaminated concrete lump 1 that is put on the upstream side (right end side in the drawing) as shown in FIG. It is configured to be transportable by flowing down toward the downstream side (same as the left end side) while vibrating.

According to the decontamination processing apparatus of the first embodiment, the contaminated concrete blocks 1 collide violently while the contaminated concrete block 1 placed on the flat wire mesh 2A is transferred from the upstream side toward the downstream side. At the same time, when the contaminated concrete block 1 comes into contact with the flat wire mesh 2A, the surface layer portion of the contaminated concrete block 1 is naturally ground and crushed, and the generated ground powder and crushed pieces pass through the mesh of the flat wire mesh 2A. It falls and is collected in the pollutant collection container 4 disposed below the flat wire mesh 2A.
On the other hand, a concrete lump of a size that cannot pass through the mesh of the flat metal mesh 2A flows down on the flat metal mesh 2A as it is and is recovered from the downstream side to the decontaminated concrete lump recovery container 6 via the discharge slope 5. It has become.

In this case, the size of the mesh of the flat wire mesh 2A needs to be set slightly larger than the crushed pieces to be collected in the pollutant collection container 4, so that the size and transfer of the contaminated concrete block 1 to be decontaminated It is necessary to appropriately set the mesh size in consideration of the size of the fragment that is expected to occur in the middle.
In addition, the vibration frequency and amplitude of the vertical vibration to be applied to the flat metal mesh 2A by the vibration mechanism 3 are set so that a desired transfer speed can be obtained in consideration of the inclination angle θ of the flat metal mesh 2A and other conditions. Appropriately set.

In order to perform decontamination processing using the decontamination processing apparatus of the first embodiment, a predetermined amount of contaminated concrete block 1 is continuously produced from the upstream side while vibrating the flat wire net 2A in the vertical direction by the vibration mechanism 3. Alternatively, it may be intermittently input.
If necessary, an appropriate pretreatment for aligning the shape and size of the contaminated concrete block 1 to be decontaminated may be performed prior to charging the flat metal mesh 2A.

  As a result, the contaminated concrete block 1 flows down to the downstream side while receiving vibration on the flat wire mesh 2A. At that time, the contaminated concrete blocks 1 are rubbed with each other. The contact with the wire mesh 2A substantially causes a surimi treatment, whereby the surface layer of the contaminated concrete block 1 is ground to generate fine ground powder, and the contaminated concrete blocks 1 collide violently. A part of the surface layer is separated into small crushed pieces, and the ground powder and crushed pieces fall through the mesh of the flat wire net 2A and are collected in the pollutant collection container 4.

On the other hand, a concrete block having a size that cannot pass through the mesh of the flat metal mesh 2A is transferred to the downstream side without dropping, discharged from the tip thereof, and collected in the decontamination concrete block collection container 6.
Therefore, the ground powder and crushed pieces generated on the flat wire mesh 2A during the transfer and the decontaminated concrete block from which the surface layer portion has been removed as ground powder and crushed pieces are each separated and collected. become.

  As described above, according to the decontamination process of the first embodiment, the radioactive substance is simply transferred by vibrating on the flat wire mesh 2A on which the contaminated concrete block 1 to be decontaminated is disposed in an inclined state. The adhering / penetrating surface layer can be ground and crushed and recovered as ground powder or crushed pieces.

  The ground powder and crushed pieces collected here contain a high concentration of radioactive substances, so appropriate treatment and disposal as radioactive waste is necessary for this. Most of the concrete blocks that have passed over the flat wire mesh 2A are already decontaminated with the radioactive material adhering to and permeating the surface layer as ground powder and crushed pieces. It can be handled as a normal clean concrete lump without hindrance.

  Therefore, according to the decontamination processing apparatus of the first embodiment, it is sufficient to perform further processing / disposal on a small amount of ground powder and crushed pieces collected in the pollutant collection container 4, and the decontaminated concrete block. The decontaminated concrete block collected in the collection container 6 can be discarded as general waste, and can be effectively used as a raw material for recycled aggregate, for example.

FIG. 2 shows a second embodiment of the decontamination processing apparatus of the present invention.
This uses a saddle-shaped wire mesh 2B having a substantially U-shaped cross section curved in a substantially U shape as shown in FIG. 2 (a) instead of a flat wire mesh as shown in FIG. 1 (a) as the wire mesh 2. As shown in FIG. 2 (c), the saddle-shaped wire mesh 2B is configured to be rockable to the left and right with its axis as the center.
In the apparatus of the second embodiment, the caged metal mesh 2B is rocked to the left and right, and the contaminated concrete lump 1 is thrown in continuously or intermittently from the upstream side as shown in FIG. 2 (b). While the contaminated concrete block 1 is swung from side to side in the vertical wire mesh 2B and transferred to the downstream side, the surface layer portion is ground and ground in the same manner as in the first embodiment. It is crushed and removed as ground powder or crushed pieces.
Therefore, also in the second embodiment, the ground powder, the crushed pieces, and the decontaminated concrete lump are separately collected in the pollutant collection container 4 and the decontaminated concrete lump collection container 6, respectively. Similar effects can be obtained.

FIG. 3 shows a third embodiment of the decontamination processing apparatus of the present invention.
This uses a cylindrical metal mesh 2C as shown in FIG. 3 (a) as the metal mesh 2 and supports the cylindrical metal mesh 2C by two drive rollers 7 as shown in FIG. 3 (c). It is configured to be rotatable about its own axis.
In the apparatus according to the third embodiment, the contaminated concrete lump 1 is continuously or intermittently charged from the upstream side as shown in FIG. The concrete lump 1 is lifted in the cylindrical wire mesh 2C and then dropped and transferred toward the downstream side, and during that transfer, the same as in the first embodiment and the second embodiment, The surface layer is ground and crushed and removed as ground powder and crushed pieces, and the ground powder, crushed pieces and decontaminated concrete lump are contaminated with the contaminant collection container 4 and decontaminated concrete lump collection container, respectively. Therefore, the same effects as those of the first and second embodiments can be obtained.

As described above, according to the decontamination processing method and the decontamination processing apparatus of the present invention, it is possible to very efficiently carry out the decontamination processing on a contaminated concrete block contaminated with radioactive substances.
In other words, if the contaminated concrete block is simply inadvertently crushed as in the usual general method, a large amount of small contaminated concrete pieces containing radioactive material are generated, and the entire amount is handled as radioactive material. Therefore, it is necessary to treat and dispose of it, which requires a lot of labor and cost, and it is not desirable to effectively use the fragmented pieces that have been contaminated.

  On the other hand, according to the present invention, while the contaminated concrete lump 1 is transferred by the wire mesh 2 arranged in an inclined state (for example, the flat wire mesh 2A, the saddle-shaped wire mesh 2B or the cylindrical wire mesh 2C as exemplified in the above embodiments). By crushing and crushing only the surface layer part where the radioactive substance adheres to and penetrates, by appropriately setting the size of the mesh of the wire mesh 2 and collecting the ground powder and crushed pieces through the mesh, Only a small amount of ground powder and crushed pieces collected through the mesh are processed and disposed of as radioactive waste, and decontamination is performed by grinding and crushing the surface layer. Since the treated concrete block can be effectively used as a resource, it is possible to significantly reduce the labor and cost required for the decontamination process.

  Although the embodiments of the present invention have been described above, the above embodiments are merely preferred examples, and the present invention is not limited to the above embodiments, and may be within the scope of the present invention. For example, the wire mesh is not limited to the flat wire mesh 2A, the saddle-shaped wire mesh 2B, or the cylindrical wire mesh 2C exemplified as each embodiment, and may be in various forms. A plurality of the same or different kinds of decontamination processing apparatuses can be arranged in series and continuously processed in multiple stages.

  In any case, in the present invention, the transfer process using the wire mesh 2 is performed as a decontamination process, so the specific embodiment of the process and the specific shape and dimensions of the wire mesh 2 that is the main body therefor, For example, whether or not the contaminated concrete block 1 is pretreated, the thickness of the surface layer to be removed during the transfer, the transfer speed, the transfer time, the transfer distance, the size of the mesh of the wire mesh 2 (the grinding to be recovered) Regarding the dimensions and shape of the powder and crushed pieces, and other specifications and specifications, take into account the size and shape of the contaminated concrete block 1 to be treated, the degree of contamination, the required decontamination performance, processing capacity and other conditions. And what is necessary is just to set optimally so that a desired decontamination effect and decontamination efficiency may be acquired.

DESCRIPTION OF SYMBOLS 1 Contaminated concrete block 2 Wire mesh 2A Flat wire mesh 2B Vertical wire mesh 2C Cylindrical wire mesh 3 Excitation mechanism 4 Contaminant collection container 5 Discharge slope 6 Decontamination concrete lump collection container 7 Drive roller

Claims (4)

A decontamination treatment method for contaminated concrete lumps for performing decontamination treatment on contaminated concrete lumps with radioactive materials adhering or penetrating on the surface,
Transfer the contaminated concrete block to be decontaminated to the upstream side of the wire mesh arranged in an inclined state with respect to the horizontal, and transfer the contaminated concrete block from the upstream side to the downstream side on the wire mesh. The surface layer of the contaminated concrete block is ground and crushed by the collision of the contaminated concrete blocks and the contact between the contaminated concrete block and the wire mesh, and the ground powder and crushed pieces generated thereby are removed from the wire mesh. A method for decontamination of a contaminated concrete mass, wherein the concrete mass after being decontaminated by dropping and collecting through a mesh and collecting and crushing the surface layer portion is collected from the downstream side of the wire mesh. A decontamination treatment apparatus for contaminated concrete blocks for carrying out the decontamination processing method for contaminated concrete blocks according to claim 1,
An apparatus for decontamination of a contaminated concrete block, wherein the metal mesh is configured by a flat metal mesh, and the metal mesh is configured to be vibrated up and down by a vibration mechanism. A decontamination treatment apparatus for contaminated concrete blocks for carrying out the decontamination processing method for contaminated concrete blocks according to claim 1,
An apparatus for decontamination of a contaminated concrete block, wherein the wire mesh is constituted by a saddle-shaped wire mesh having a substantially U-shaped cross section, and the saddle-shaped wire mesh is configured to be rockable to the left and right around its axis. A decontamination treatment apparatus for contaminated concrete blocks for carrying out the decontamination processing method for contaminated concrete blocks according to claim 1,
An apparatus for decontamination of a contaminated concrete block, wherein the wire mesh is constituted by a cylindrical cylindrical wire mesh, and the cylindrical wire mesh is configured to be rotatable about its axis.

Images