JP7214448B2 - Decontamination treatment method and decontamination treatment apparatus for contaminated concrete mass - Google Patents

Description

TECHNICAL FIELD The present invention relates to a decontamination treatment method and a decontamination treatment apparatus for a contaminated concrete block having a contaminated surface.

In the event of an accident at a nuclear-related facility such as a nuclear power plant or in the course of decommissioning work, a large amount of debris (mainly debris such as concrete blocks) contaminated with radioactive substances is generated. Since these rubbles are radioactive waste whose surfaces are contaminated with radioactive cesium, decontamination is performed by scraping the surface layer.

After decontamination, the fine powder generated by scraping the surface layer is treated as high-level waste, and the remaining portion is treated as low-level radioactive waste. Volume reduction is possible. That is, high-level radioactive waste will be strictly stored and managed in the future, and low-level radioactive waste will be stored and recycled according to radiation dose to reduce the volume of waste.

Various methods have been proposed for decontamination of the surface of debris contaminated with radioactive substances (see Patent Documents 1 to 5, for example). According to these methods, although there are individual differences, in all cases, the surface layer of the glass is crushed by rubbing the glass together and applying force to the surface layer of the glass to remove the surface layer of the glass. be able to. In addition, these methods collect the fine powder while scraping the surface layer of the shell.

JP 2017-227493 A JP 2014-109559 A JP 2014-115159 A JP 2014-109560 A JP 2012-213750 A

However, when the above-described technology is applied to large-sized waste to perform decontamination treatment, there is a problem that the size of the device increases. In addition, when trying to decontaminate scraps of various sizes, not only does the equipment become bulky, but in the process of chipping the surface, sufficient force is not applied to the surface, resulting in uneven chipping. There is a problem of being able to In addition, there is a problem that fine powder containing a high concentration of radioactive cesium generated during the chipping process re-adheres to the shell being fished.

The present invention has been made in view of the above-mentioned problems, and even if the debris to be decontaminated contains lumps of various sizes, the decontamination can be performed reliably while simplifying the apparatus. An object of the present invention is to provide a decontamination treatment method and a decontamination treatment apparatus for contaminated concrete masses.

In order to achieve the above object, the present invention provides a decontamination treatment method for a concrete mass whose surface layer is contaminated with a radioactive substance, wherein the concrete mass is compressed and crushed so as to be sandwiched between plate-like bodies to a predetermined amount. A crushing step of generating concrete fragments smaller than the size, a grinding step of grinding the surface layer of the concrete fragments with rotating rollers to generate recycled fragments and fine powder, and the recycled fragments and fine powder are accumulated. and a separation step of sieving with a sieve to separate the recycled fragments from the fine powder.

According to the present invention, since the concrete lumps are compressed and crushed so as to be sandwiched between plate-like bodies, even if the concrete lumps to be decontaminated contain lumps of various sizes, concrete with a uniform particle size can be obtained. Can generate shards. Further, according to the present invention, by grinding the surface layer of the generated concrete fragments with rollers, the surface layer contaminated with radioactive substances can be scraped off to generate decontaminated recycled fragments. In addition, according to the present invention, the generated recycled fragments and fine powder are sieved through a sieve to separate fine powder and recycled fragments contaminated with radioactive substances, thereby reducing the volume of radioactive waste and facilitating subsequent treatment. can be

In the present invention, the crushing process further comprises a fixed plate fixed in a substantially vertical direction and a movable plate arranged to face the fixed plate with a space therebetween and swinging about a rotation axis. It may be configured to compress and crush.

ADVANTAGE OF THE INVENTION According to this invention, the particle size of the concrete fragment produced|generated by pinching and compressing and crushing a lump of concrete with a fixed plate and a moving plate can be made uniform.

The present invention further provides that the grinding step applies a constant force to the concrete fragments between a turntable having a rotating surface on which the concrete fragments are placed and the rotating rollers, so that the surface layer of the concrete fragments is crushed. It may be configured to grind the part.

According to the present invention, a product with a reduced level of radioactivity can be produced by grinding the surface layer of concrete fragments contaminated with radioactive substances.

Further, in the present invention, the separating step uses a cylindrical sieve that rotates about a rotation axis along an extending direction inclined with respect to a horizontal plane, and the recycled fragments and fine powder are accumulated in the sieve and rotated. The fine powder dropped from the sieve and the recycled fragments remaining on the sieve may be separately collected.

According to the present invention, fine powder with a high level of radioactivity and regenerated fragments with a low level of radioactivity can be separated and collected by sieving, and the waste can be treated according to the level of radioactivity.

Further, the present invention provides a decontamination processing apparatus for decontaminating a contaminated concrete mass whose surface layer is contaminated with a radioactive substance, wherein the concrete mass is compressed and crushed so as to be sandwiched to reduce the size to a predetermined size or less. A crushing device having a pair of plates for generating concrete fragments, a grinding device having rotatable rollers for grinding the surface layer of the concrete fragments to produce recycled fragments and fine powder, and a horizontal surface. A decontamination process characterized by comprising a cylindrical sieve that rotates around a rotation axis extending in an inclined extending direction, and a separation device that sieves the accumulated recycled fragments and the fine powder. It is a device.

A crushing device produces concrete fragments with uniform particle diameters, a grinding device grinds the surface layer of the concrete fragments to produce recycled fragments and fine powder, and a separation device produces recycled fragments with a low level of radioactivity. Fine powder with a high level of radioactivity can be separated, and radioactive waste can be managed according to the level of radioactivity.

According to the present invention, even if the debris to be decontaminated includes lumps of various sizes, the decontamination can be reliably performed while simplifying the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the decontamination processing apparatus of the contaminated concrete mass which concerns on embodiment of this invention. 4 is a flow chart showing the flow of each step of a method for decontamination treatment of contaminated concrete masses.

EMBODIMENT OF THE INVENTION Hereafter, embodiment of the decontamination processing method and decontamination processing apparatus of the contaminated concrete lump which concerns on this invention is described, referring drawings.

As shown in FIG. 1, the decontamination treatment apparatus 1 includes a crushing apparatus 10 that crushes a concrete mass M to generate concrete fragments C, and a surface layer portion of the concrete fragments C that is ground to produce recycled fragments and fine powder. It comprises a grinding device 20 for producing and a separating device 30 for separating regenerated fragments and fines.

The crushing device 10 is, for example, a jaw crusher. The crushing device 10 clamps a concrete mass M between a pair of plate-like bodies and applies stress in the compression direction to compressively crush the mass to generate concrete fragments C of a predetermined size or less. The crushing device 10 includes a fixed plate 11 fixed substantially vertically. The fixed plate 11 is formed in a plate shape, for example.

The fixed plate 11 is ensured with a rigidity that can withstand crushing of the concrete mass M. A plate-like moving plate 12 is arranged to face the fixed plate 11 . The moving plate 12 is arranged so that the distance between the moving plate 12 and the fixed plate 11 decreases as it goes downward. A lower portion of the moving plate 12 is rotatably supported by a fulcrum 13 . The position of the fulcrum 13 is changed so that the distance between the fixed plate 11 and the lower part of the moving plate 12 is adjustable. An upper portion of the moving plate 12 is supported by an eccentric shaft 15 . The eccentric shaft 15 is connected to the shaft 14 that rotatably supports the flywheel 16 .

An upper portion of the moving plate 12 is supported by an eccentric shaft 15 . When the flywheel 16 rotates, the eccentric shaft 15 connected to the shaft 14 rotates eccentrically, and the moving plate 12 swings around the fulcrum 13 (rotating shaft). When the concrete mass M is put between the fixed plate 11 and the moving plate 12 , the concrete mass M is sandwiched between the fixed plate 11 and the moving plate 12 . When the moving plate 12 swings, the concrete mass M is sandwiched between the fixed plate 11 and the moving plate 12 and subjected to compressive stress to be compressed and crushed.

Concrete fragments C generated by compression and crushing fall down and are sandwiched between the fixed plate 11 and the moving plate 12 again, and are further compressed and crushed. In this way, the concrete fragments C fall while repeatedly being compressed and crushed between the fixed plate 11 and the moving plate 12, gradually decreasing in particle size, and finally moving with the tip of the fixed plate 11. It falls from the gap D between the tip of the plate 12. - 特許庁

The gap D is adjusted by the fulcrum 13 to be approximately a predetermined distance. The predetermined distance is changed by adjusting the position of the fulcrum 13, and is adjusted so that the particle size of the generated concrete fragments C is less than or equal to a predetermined value (for example, about 10 [cm]).

With such a configuration, the crushing device 10 can generate concrete fragments C having uniform particle diameters from concrete lumps M having different sizes. Concrete fragments C dropped from the crushing device 10 are accumulated in a crushing device 20 where the next process is performed by a belt conveyor B or the like.

The grinding device 20 is, for example, a roller mill. The grinding device 20 grinds the surface layer of the concrete fragments C with rollers to produce recycled fragments R and fine powder P. As shown in FIG. As a result, the surface layer of concrete fragments C whose surfaces are contaminated with radioactive substances can be scraped off to generate recycled fragments R, thereby reducing the level of radioactivity.

The grinding device 20 comprises, for example, a rotating table having a rotating surface on which the concrete fragments C are placed. The turntable includes, for example, a disk-shaped table 21 and a cylindrical side wall 22 formed to surround the outer circumference of the table 21 . A roller 23 is rotatably provided on the upper portion of the side wall 22 at a predetermined distance upward from the table 21 . The predetermined distance is adjusted to a value approximately equal to the particle diameter of the concrete fragments C (for example, approximately 10 [cm]).

A concrete fragment C is placed on the table 21 . The roller 23 rotates in conjunction with the rotation of the table 21 . The grinding device 20 applies a constant force to the concrete fragments C between the rotating table 21 and the rotating rollers, and grinds the concrete fragments C so that the surface layer of the concrete fragments C is scraped off by about 2 [mm]. From the concrete fragments C whose surface layer has been ground, recycled fragments R having a particle diameter smaller than that of the concrete fragments C by about 1 to 2 [mm] and fine powder P are produced. The fine powder P is, for example, powder having a particle size of 2 [mm] or less. When the treatment of the grinding device 20 is performed, the product contains a mixture of recycled fragments R and fine powder P, so the product is collected and separated by a separation device for separating the product by a belt conveyor B or the like. 30 is thrown in.

The separating device 30 comprises, for example, a rotatable cylindrical sieve 31 . The sieve 31 is installed, for example, with its axis of rotation inclined with respect to the horizontal plane. In the sieve 31 , the opening at the higher position is the inlet 32 and the opening at the lower position is the outlet 33 . The sieve 31 has a mesh structure, and the mesh is formed so that the fine powder P does not pass through the recycled fragments R. That is, the separation device 30 is a device that separates the recycled fragments R and the fine powder P by sieving them with a sieve 31 in which the recycled fragments R and the fine powder P are accumulated. The separating device 30 puts the regenerated fragments R and the fine powder P collected from the grinding device 20 into the inlet 32 of the sieve 31 and accumulates them in the sieve 31 .

When the sieve 31 is rotated, inside the sieve 31, the accumulated recycled fragments R and fine powder P roll at the bottom. At this time, the fine powder P passes through the gaps of the sieve 31 and falls downward. When the sieve 31 continues to rotate, the sieve 31 vibrates, the regenerated fragments R rolling inside rub against each other, and the surfaces of the regenerated fragments R rub against each other due to friction with the sieve 31, and adhere to the surfaces of the regenerated fragments R. The fine powder P separated from the surface of the recycled fragments R passes through the gaps of the sieve 31 and falls downward. The fine powder P is recovered below the sieve 31 . Recycled pieces R from which the fine powder P has been removed remain in the sieve 31 .

Since the sieve 31 is installed at an angle, the regenerated fragments R roll from the input port 32 side to the output port 33 side as the sieve 31 rotates. As the sieve 31 continues to rotate, the recycled fragments R come out of the sieve 31 through the outlet 33 and fall. The fallen recycled fragments R are collected below the sieve 31 . The installation angle of the sieve 31 is adjusted in consideration of the rotational speed of the sieve 31, the moving speed (residence time) of the regenerated fragments R in the sieve 31, and the like. According to the separation device 30, the fine powder P dropped from the sieve 31 and the recycled fragments R remaining on the sieve 31 can be collected separately.

Since the fine powder P contains radioactive substances adhering to the surface of the concrete mass M, it is accumulated as high-level radioactive waste and strictly managed according to standards. Since the surface layer of the recycled fragment R is scraped off by the grinder 20, the radioactive level is lowered. Recycled fragments R are recycled as aggregate or the like according to the remaining radioactive level, and are also accumulated as radioactive waste and managed according to standards.

Next, the method for decontaminating contaminated concrete masses according to the present invention will be described. FIG. 2 is a flow chart showing the flow of each step of the decontamination treatment method for contaminated concrete masses.

First, concrete lumps are collected from the site (step S10). Next, the accumulated concrete lumps M, in which large and small lumps are mixed, are put into the crusher 10 and compressed and crushed to generate concrete fragments C having uniform particle diameters (step S11). Next, the generated concrete fragments C are put into the grinding device 20, and the surface layer is ground to generate recycled fragments R and fine powder P (step S12). Next, the regenerated fragments R and the fine powder P are put into the separation device 30, and the regenerated fragments R and the fine powder P are sieved and separated (step S13). Next, the regenerated fragment R and the fine powder P are individually collected and individually managed according to their radioactive levels (step S14).

As described above, the contaminated concrete block decontamination treatment apparatus 1 can be applied as it is to debris such as concrete blocks mixed in various sizes. According to the decontamination processing apparatus 1, even if there are concrete blocks of various sizes in the crushing process, the size of the final decontaminated product can be approximately uniform. Therefore, according to the decontamination treatment apparatus 1, subsequent treatment of the recovered product can be facilitated. Moreover, according to the decontamination treatment apparatus 1, waste can be separated according to the radioactive level, and can be treated according to the radioactive level of the waste. Therefore, according to the decontamination processing apparatus 1, radioactive waste can be reduced.

An embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the scope of the invention. For example, the crushing device, grinding device, and separation device described above are examples, and other devices may be used as long as they can perform the same treatment.

1 Decontamination treatment device 10 Crushing device 11 Fixed plate 12 Moving plate 13 Support point 14 Shaft 15 Eccentric shaft 16 Flywheel 20 Grinding device 21 Table 22 Side wall 23 Roller 30 Separating device 31 Sieve 32 Input port 33 Carry-out port B Belt conveyor C Concrete Fragment D Gap M Concrete mass P Fine powder R Recycled fragment

Claims (5)

A decontamination treatment method for a concrete mass whose surface layer is contaminated,
a crushing step of compressing and crushing the concrete mass so as to hold it between plate-like bodies to generate concrete fragments of a predetermined size or less;
a grinding step of grinding the surface layer of the concrete fragments with rotating rollers to produce recycled fragments and fine powder;
a separation step of sieving with a sieve in which the recycled fragments and the fine powder are accumulated to separate the recycled fragments and the fine powder;
A method for decontaminating a contaminated concrete mass, comprising: In the crushing step, the concrete mass is compressed and crushed between a fixed plate fixed in a substantially vertical direction and a moving plate that is spaced apart from the fixed plate so as to face the fixed plate and that swings about a rotation axis.
The method for decontaminating a contaminated concrete mass according to claim 1. In the grinding step, a constant force is applied to the concrete fragments between a turntable having a rotating surface on which the concrete fragments are placed and the rotating rollers to grind the surface layer of the concrete fragments. ,
The method for decontaminating a contaminated concrete mass according to claim 1 or 2. In the separation step, a cylindrical sieve that rotates around a rotation axis extending in an extending direction inclined with respect to a horizontal plane is used, and the regenerated fragments and the fine powder are accumulated in the sieve and separated from the rotating sieve. separately recovering the fine powder that has fallen and the recycled fragments remaining on the sieve;
The method for decontaminating a contaminated concrete mass according to any one of claims 1 to 3. A decontamination treatment device for decontaminating a concrete mass whose surface layer is contaminated,
a crushing device having a pair of plate-like bodies for compressing and crushing the concrete lumps so as to sandwich them to generate concrete fragments of a predetermined size or less;
a grinding device having rotatable rollers for grinding the surface layer of the concrete fragments to produce recycled fragments and fine powder;
a separation device comprising a cylindrical sieve that rotates around a rotation axis extending in an extending direction inclined with respect to a horizontal plane, and sieving the accumulated recycled fragments and the fine powder;
A decontamination treatment device comprising:

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