JP6052538B2 - Decontamination processing method and apparatus for contaminated concrete block - Google Patents

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 of a sound concrete structure and its demolition, such a method is used for decontamination of contaminated concrete blocks. It cannot be applied as a dyeing treatment method as it is.

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

The invention according to claim 1 is a method for decontamination of a contaminated concrete block for performing a decontamination process on a contaminated concrete block having a radioactive substance adhering or penetrating on its surface, and the contamination of the decontamination target The surface layer of the contaminated concrete lump is ground by agitating only the concrete lump in the sealed container, and grinding powder generated in the sealed container by the lump treatment is contained in the sealed container. It is characterized by recovering by sucking from the.

Invention of Claim 2 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: Only the contaminated concrete block of decontamination processing object is accommodated. Occurred in the sealed container by a ground container, a stirrer for grinding the surface layer of the contaminated concrete lump by stirring only the contaminated concrete lump in the closed container and grinding It is characterized by comprising a suction device for sucking and collecting the crushed powder from the sealed container.

  According to the present invention, the contaminated concrete lump is subjected to a grinding process in the sealed container, so that only the surface layer portion to which the radioactive substance is adhered and permeated is slightly removed, and the ground powder generated thereby is removed in the sealed container. By collecting and sucking in, it is possible not only to prevent the ground powder containing radioactive material from scattering to the surroundings, but also to treat only a very small amount of the collected ground powder.・ It is only necessary to dispose of it, and it is also possible to effectively use the concrete block after decontamination treatment as a resource, and it is possible to greatly reduce the labor and cost required for the decontamination treatment.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic structure of the decontamination processing apparatus which is embodiment of this invention is shown, (a) is a plane sectional view, (b) is a sectional side view.

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.
FIG. 1 shows a schematic configuration of a decontamination processing apparatus according to the present embodiment, in which (a) is a plan sectional view and (b) is a side sectional view.

  The decontamination processing method according to the present embodiment is directed to a contaminated concrete block 1 that has occurred due to, for example, an accident in a nuclear facility such as a nuclear power plant or a dismantling or renewal work for a nuclear facility. This method is used to decontaminate radioactive substances adhering to and permeating the surface layer, and the decontamination processing apparatus of this embodiment shown in FIG. 1 can be suitably used as an apparatus for carrying out the method. It is a thing.

In the present invention, the contaminated concrete block 1 (concrete block contaminated with the radioactive substance) to be decontaminated is contaminated with the radioactive substance, but the radioactive substance 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 process for such a contaminated concrete block 1, 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 grinds the surface layer portion of the contaminated concrete lump 1 by stirring and contaminating the contaminated concrete lump 1 to be decontaminated in an airtight container. The ground powder generated in the sealed container by the grinding process is sucked and collected from the sealed container.

  Further, the decontamination processing apparatus of the present embodiment includes a sealed container that houses the contaminated concrete block 1 to be decontaminated and a contaminated concrete block in the sealed container in order to efficiently perform the above decontamination processing method. A stirrer that grinds the surface layer of the contaminated concrete lump 1 by stirring 1 and grinds the ground powder generated in the sealed container by the grinding process and collects the ground powder. It is characterized by having a suction device.

The structure of the decontamination processing apparatus of this embodiment is demonstrated concretely with reference to FIG.
In FIG. 1, the code | symbol 2 is a vertical cylindrical airtight container which accommodates the contaminated concrete block 1 of a decontamination process target.
As shown in FIG.1 (b), the upper part of the airtight container 2 is open | released as an inlet for throwing in the contaminated concrete lump 1, and the cover body 3 comes to be attached so that sealing is possible there. Yes. Moreover, the discharge port 4 for taking out the concrete lump after a process is provided in the bottom part of the airtight container 2, The revolving door 5 is provided in it so that sealing is possible.

  A stirring device 6 is provided in the sealed container 2. The stirring device 6 includes a motor 7 provided at the center of the bottom of the sealed container 2, a rotating shaft 8 that is driven to rotate by the motor 7, and a plurality of stirring provided radially around the rotating shaft 8. It consists of wings 9 (three stages in the illustrated example, a total of six).

  A suction port for sucking internal air is provided on the side of the bottom of the sealed container 2, and a suction duct 10 is connected to the suction port. A suction device (not shown) such as a blower is provided at the tip of the suction duct 10. Are connected, and the ground powder generated in the sealed container 2 by the decontamination process is sucked by the suction device through the suction duct 10 and can be collected.

Since air corresponding to the amount of suction by the suction device needs to be sucked into the sealed container 2, the airtight performance of the lid 3 and the revolving door 5 is adjusted accordingly to allow a slight gap. Alternatively, if necessary, an inlet for allowing external air to flow into the sealed container 2 may be provided at an appropriate position.
In any case, keep the inside of the sealed container 2 at a negative pressure during the grinding process so that the ground powder does not inadvertently leak to the outside and contaminate the surroundings. Should.

In order to perform the decontamination process using the decontamination apparatus having the above-described configuration, a predetermined amount of contaminated concrete block 1 is put into the sealed container 2 in a state where the discharge port 4 is closed by the revolving door 5, and the lid 3 is attached. The contaminated concrete block 1 may be closed and sealed in the sealed container 2, and the contaminated concrete block 1 may be stirred by the stirring device 6 in this state.
Prior to putting the contaminated concrete block 1 to be decontaminated into the sealed container 2, if necessary, an appropriate pretreatment for aligning the shape and size thereof may be performed.

As a result, the contaminated concrete lumps 1 are naturally rubbed together in the closed container 2 to be subjected to a grinding process, whereby the surface layer portion of the contaminated concrete lumps 1 is ground and fine ground powder is generated, The ground powder is sucked and collected by the suction device through the suction duct 10.
After grinding the surface layer of the contaminated concrete block 1 by a desired thickness (a few millimeters is sufficient) by grinding for a predetermined time, the swivel door 5 is opened and the treated concrete block is removed from the discharge port 4. Just drop it and take it out.

  As described above, in the decontamination processing method and apparatus of the present embodiment, the contaminated concrete block 1 is simply subjected to the grinding process with the stirring device 6 in the sealed container 2 in the contaminated concrete block 1. The surface layer portion of 1 is rubbed to generate ground powder, and the ground powder is directly sucked and collected from the sealed container 2 by the suction device without being scattered around.

  The ground powder recovered by the suction device contains a high concentration of radioactive substances, so that appropriate treatment and disposal are necessary for this, but the surimi treatment is performed in the sealed container 2. Since the radioactive material adhering to and permeating the surface layer of the concrete block is removed as ground powder and is sufficiently decontaminated, it can be handled without any problem as a normal clean concrete block. It will be a thing.

  Therefore, according to the decontamination processing method and apparatus of the present embodiment, it is sufficient to perform further processing / disposal on the collected small amount of ground powder, and the concrete block after the decontamination processing is discarded as general waste. In addition to being able to be disposed of, it can be effectively used as a raw material for recycled aggregate, for example.

As described above, according to the present invention, it is possible to perform the decontamination process on the contaminated concrete block 1 contaminated with the radioactive substance extremely safely and efficiently.
That is, if the contaminated concrete block 1 is simply inadvertently crushed as it is in the conventional general method, not only there is a concern that the radioactive material will be scattered around, but also a concrete piece containing the radioactive material. Is generated in large quantities, and it becomes necessary to treat and dispose of the entire amount as radioactive material, which requires a lot of labor and cost, and makes effective use of decontaminated concrete pieces. I can't hope for that.

  On the other hand, according to the present invention, the contaminated concrete block 1 is simply smeared in the sealed container 2 to remove only a few millimeters of the surface layer portion on which the radioactive material is adhered and permeated, and then sealed. By collecting the ground powder from the container 2 as a ground powder, it is possible not only to prevent the ground powder containing radioactive material from being scattered around, but also to collect only a small amount of the collected ground powder. It is only necessary to treat and dispose of it finally, and the concrete debris after decontamination can be effectively used as resources, so it is possible to significantly reduce the labor and cost required for decontamination. .

  Although the embodiment of the present invention has been described above, the above embodiment is merely a preferred example, and the present invention is not limited to the above embodiment, so long as it does not depart from the gist of the present invention. That is, as long as the contaminated concrete block is subjected to a grinding process in a closed container and the ground powder generated thereby is sucked and collected, the present invention can be appropriately changed in design and applied.

  For example, in the decontamination processing method of the above embodiment, the decontamination process is performed by batch processing. Therefore, in the decontamination processing apparatus of the above embodiment, the sealed container 2 is a vertical cylindrical container for batch processing. The decontamination treatment method of the present invention can also be continuously processed while continuously transferring the contaminated concrete block. In that case, the sealed concrete block 2 is rubbed for a predetermined time while continuously transferring the contaminated concrete block. What is necessary is just to set it as the structure which can be processed.

  In any case, the concrete process of the surimi treatment as a decontamination process, the specific configuration of each part for the surimi treatment and its specifications, for example, the presence or absence of pretreatment, should be ground by the surimi treatment Regarding the thickness of the surface layer, the processing time, the capacity and form of the sealed container, the specific configuration of the stirring device and the suction device, etc., the size and shape of the contaminated concrete block to be treated, the degree of contamination, are required. In consideration of various conditions such as decontamination performance, processing capacity, etc., it may be optimally set so as to obtain a desired decontamination effect and decontamination efficiency.

DESCRIPTION OF SYMBOLS 1 Contaminated concrete block 2 Sealed container 3 Lid 4 Discharge port 5 Revolving door 6 Stirrer 7 Motor 8 Rotating shaft 9 Stirring blade 10 Suction duct

Claims (2)

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,
Only the contaminated concrete block to be decontaminated is agitated and ground in the sealed container to grind the surface layer of the contaminated concrete block, and the grinding generated in the sealed container by the ground process. A method for decontamination of a contaminated concrete mass, wherein powder is sucked and collected from the inside of the closed container. A decontamination treatment apparatus for contaminated concrete blocks for carrying out the decontamination processing method for contaminated concrete blocks according to claim 1,
A sealed container containing only contaminated concrete blocks to be decontaminated,
An agitation device for grinding the surface layer portion of the contaminated concrete lump by agitating only the contaminated concrete lump in the sealed container and processing the soil;
An apparatus for decontamination of contaminated concrete mass, comprising a suction device for sucking and collecting ground powder generated in the sealed container by the grinding process from the sealed container.

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