JP6409202B2 - Truck carrier mat - Google Patents

Description

  The present invention relates to a truck bed mat that prevents radioactive material from flowing out from a transport truck when transporting the radioactive waste accumulated in a temporary storage site or the like by decontamination by truck to an intermediate storage facility.

  The earthquake and tsunami that hit East Japan on March 11, 2011 caused a serious nuclear accident at the Fukushima Daiichi NPS. The radioactive cesium discharged from this accident was scattered not only in Fukushima Prefecture, but also in the Tohoku and Kanto regions, but now decontamination work is progressing in various areas for reconstruction.

  Radioactive waste such as contaminated soil collected from various locations is once accumulated in a temporary storage area and then transported to an intermediate storage facility. When transporting radioactive waste to an intermediate storage facility, a general transport truck is used. However, in a normal transport truck, since the cargo bed has poor liquid-tightness, the exudate exuding from the radioactive waste may leak from the truck bed during transportation. This exudate contains a radioactive substance such as radioactive cesium, and leakage of exudate is a problem because it causes recontamination.

  As an example of dealing with such a leakage problem of a transportation truck, for example, a dump truck carrier described in Patent Document 1 can be cited. In this dump truck transporter, in order to make the transporter liquid-tight, it has been proposed that the bottom plate and the peripheral wall be integrally formed of a rubber-like elastic body (elastomer) such as natural rubber, synthetic rubber, or thermoplastic elastomer. ing.

JP2013-252822A (Claim 1, paragraph 0031, etc.)

  However, although the truck carrier described in Patent Document 1 can solve the problem of leakage of exudate, there is no sufficient countermeasure for the case where exudate containing radioactive material leaks from the transport truck. Therefore, further improvement was required from the viewpoint of safety.

  In addition, dump trucks are generally used as transport trucks because it is easy to check the load and divert according to the situation at the site, and the size and shape of the loading platform is the situation at the site where radioactive waste is loaded. And depending on the amount of load. However, since the bottom plate and the peripheral wall are already integrally formed in the truck carrier as described in Patent Document 1, it is not easy to transfer from one dump truck to another dump truck at the site. In addition, it was necessary to secure a place for storing the transport equipment, and there was room for improvement in terms of convenience.

  Under such circumstances, an object of the present invention is to provide a truck bed mat that can transport radioactive waste more safely than before and can be easily replaced and stored.

  As a result of intensive studies to solve the above problems, the present inventors have laminated a radioactive cesium adsorbing sheet on a base rubber sheet, and further has a water permeable presser on the radioactive cesium adsorbing sheet. It has been found that by laminating rubber sheets, a safer and more efficient work platform mat can be obtained, and the present invention has been completed.

That is, the truck bed mat according to the present invention has the gist in the following points.
[1] For a truck bed that can be rolled up, wherein a radioactive cesium adsorption sheet is laminated on a base rubber sheet, and a pressing rubber sheet having water permeability is laminated on the radioactive cesium adsorption sheet mat.
[2] The truck bed mat according to [1], wherein in the base rubber sheet, a side part extends from a bottom surface part, and the side part extends from the radioactive cesium adsorption sheet and the pressing rubber sheet. .
[3] The truck bed mat according to [1] or [2], wherein a magnet sheet is fixed to a back surface of the base rubber sheet.
[4] The truck bed mat according to [2], wherein the side portion includes at least one metal element selected from barium, tungsten, and lead and a metal compound including the metal.

  ADVANTAGE OF THE INVENTION According to this invention, the mat | matte for truck bed which can carry a radioactive waste still more safely than before, and is easy to load and store is provided.

FIG. 1 is a schematic sectional view of a truck bed mat according to the present invention. FIG. 2 is a diagram illustrating a state in which the truck bed mat according to the present invention is loaded on the truck bed. FIG. 3 is a schematic perspective view showing an example of a base rubber sheet with side portions extending from the bottom surface portion. FIG. 4 is a schematic top view showing another example of the base rubber sheet having an overlap in the side part.

  Hereinafter, the truck bed mat according to the present invention will be specifically described with reference to the drawings showing the embodiments. However, the present invention is not limited to the illustrated examples, and conforms to the purpose described above and below. It is also possible to carry out the present invention with appropriate modifications within the range to be obtained, all of which are included in the technical scope of the present invention.

<Embodiment 1>
FIG. 1 is a schematic sectional view of a truck bed mat 10 according to the present invention. In the truck carrier mat 10 according to the present invention, a radioactive cesium adsorption sheet 2 is laminated on a base rubber sheet 1, and a water-permeable pressing rubber sheet 3 is laminated on the radioactive cesium adsorption sheet 2. It is characterized in that The truck carrier mat 10 is installed on the carrier of the transport truck with the base rubber sheet 1 side down, and is used by loading radioactive waste such as a flexible container bag on the holding rubber sheet 3 side.

  The base rubber sheet 1 improves the followability to the loading platform and increases the frictional force against the loading platform. Thereby, the shift | offset | difference of the truck bed mat 10 by the shaking at the time of transportation, etc. can be suppressed. Further, by adopting the rubber sheet, water shielding is also exhibited, and it is possible to prevent the exudation water from the radioactive waste from leaking from the transport truck.

  And by providing the radioactive cesium adsorption sheet 2 in an intermediate | middle layer, radioactive substances, such as radioactive cesium contained in the exudation water, can be adsorbed. Therefore, even if the exudate leaks to the outside, it is safe because it will not be recontaminated.

  Furthermore, the pressing rubber sheet 3 having water permeability is laminated on the radioactive cesium adsorption sheet 2, and the radioactive cesium adsorption sheet 2 is pressed from above by the weight of the pressing rubber sheet 3. Thereby, it can suppress that the radioactive cesium adsorption sheet 2 rolls up by the wind etc. during transport, or the radioactive cesium adsorption sheet 2 shifts | deviates at the time of loading.

  The presser rubber sheet 3 having water permeability has holes to exhibit water permeability. The shape of the hole is not particularly limited, and may be, for example, a circle, a polygon (for example, a triangle, a rectangle, etc.), and the pressing rubber sheet 3 may be a mesh. Due to the presence of these holes, exudate can pass through the pressing rubber sheet 3 and can come into contact with the radioactive cesium adsorbing sheet 2. In addition, the presence of the holes in the holding rubber sheet 3 makes it possible to appropriately hold the radioactive waste loaded thereon, and to suppress damage during movement, loading, and vibration during transportation.

  In addition, in the truck carrier mat 10 according to the present invention, the base rubber sheet 1, the radioactive cesium adsorption sheet 2, and the pressing rubber sheet 3 are all flexible. By laminating flexible layers, the truck bed mat 10 can be rolled up. Therefore, when storing the truck bed mat 10 according to the present invention, the truck bed mat 10 can be rolled up into a roll shape, which contributes to space saving of the storage place. Furthermore, the truck bed mat 10 wound up in a roll shape can be easily loaded on the bed of the transport truck, and the truck bed mat 10 itself can be easily transported. In addition, since the truck bed mat 10 is in the form of a sheet, it can be easily installed on the bed of the transport truck by opening the roll. For this reason, it is possible to easily carry out the transfer work between the transport trucks.

  Moreover, since the pressing rubber sheet 3 can be removed relatively easily, the radioactive cesium adsorption sheet 2 can be periodically replaced.

  The truck bed mat 10 may be formed in a rectangular shape, for example, in accordance with the shape of the bed of the transport truck.

  And it is desirable that the weir 4 is fixed or attached to the outer periphery of the truck bed mat 10 so that the exudate is not leaked to the outside. Thus, by using not only the base rubber sheet 1 but also the weir 4, it is safe because it is possible to more reliably prevent the exudate from leaking from the transport truck. The shape and material of the weir 4 are not particularly limited as long as the water barrier can be exhibited. For example, the weir 4 may be a laminated body of sheets having a water barrier, and is an integrally molded product with the base rubber sheet 1 as described later. There may be.

  Further, it is preferable that a fixing member 5 such as a magnet sheet is fixed to the back surface of the base rubber sheet 1 so that the truck bed mat 10 does not move due to shaking or wind during transportation.

  FIG. 2 is a diagram illustrating a state in which the truck bed mat 10 according to the present invention is loaded on the bed of the truck 20. As described above, the truck bed mat 10 according to the present invention may be loaded on the bed of the truck 20 with the base rubber sheet 1 facing down, as described above.

  In consideration of the safety of people around the truck 20 including the driver, it is preferable to provide a shielding sheet 30 having a shielding property against radiation at the front, side, and rear side. It is not always necessary to provide the shielding sheet 30 on all four sides, but from the viewpoint of improving safety, it is preferable to install the shielding sheet 30 on all four sides. The radioactive cesium shielding sheet is, for example, a magnet or the like. It is desirable that it is fixed in a tilt by a fixing member 31 such as a screw.

  Hereinafter, each member constituting the truck bed mat 10 will be described in detail.

[Base rubber sheet / pressing rubber sheet]
The base rubber sheet and the pressing rubber sheet are preferably made of a flexible material, and as these sheet base materials, for example, rubber or elastomer can be suitably used. Examples of the rubber include natural rubber, chloroprene rubber, silicone rubber, ethylene propylene rubber, ethylene propylene diene rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, and blends thereof. Examples of the elastomer include polyester, polyolefin, Examples thereof include silicone-based thermoplastic elastomers. Among these, use of rubber is desirable, and ethylene propylene diene rubber is more preferable.

  For example, the thickness of the base rubber sheet is preferably 0.3 to 5 mm, more preferably 0.5 to 4 mm, and more preferably 1 to 3 mm. In order to suppress leakage of exudate at a higher level, the base rubber sheet preferably has a seamless seamless structure.

  The thickness of the pressing rubber sheet is preferably 2 to 12 mm, and more preferably 5 to 10 mm, for example.

[Radioactive cesium adsorption sheet]
Next, the radioactive cesium adsorption sheet will be described. The radioactive cesium adsorption sheet is not particularly limited as long as the adsorption performance for radioactive cesium is exhibited, for example, a sheet material containing a radioactive cesium adsorbent, a sheet material containing a highly water-absorbing swelling fiber, etc. Can be mentioned.

  As the radioactive cesium adsorption sheet, for example, an aspect in which the radioactive cesium adsorbent is fixed to the base material surface of the radioactive cesium adsorption sheet, or an aspect in which the radioactive cesium adsorbent is mixed as a base material of the radioactive cesium adsorption sheet Is mentioned.

  Examples of the base material of the radioactive cesium adsorption sheet include fabrics made of fibers such as nonwoven fabrics, woven fabrics, knitted fabrics, braids, laces, and nets; foams; papers; films made of thermoplastic resins; and laminates thereof. Preferred examples of the nonwoven fabric include wet nonwoven fabrics such as chemical bonds, thermal bonds, and spunlaces; dry nonwoven fabrics such as chemical bonds, thermal bonds, spunlaces, and needle punches; and spunbond nonwoven fabrics. The woven fabric is preferably a woven fabric having a woven structure such as plain weave, twill weave and satin weave. Furthermore, examples of the knitted fabric include knitted fabrics in which the knitting structure is a weft knitting (flat knitting, rib knitting, double-sided knitting, pearl knitting), warp knitting (tricot knitting, raschel) or the like. As the foam, a foam made of polyurethane, polyethylene, polyvinyl chloride, polybutadiene or the like is preferably used. Among these, non-woven fabrics are more preferable because they are relatively dense between fibers, can be manufactured at low cost, and have high water retention, and spunbonded non-woven fabrics are more preferable.

  Further, when the fabric is included in the base material of the radioactive cesium adsorption sheet, the fibers used in the fabric include polyester fibers such as polyethylene terephthalate fibers, polytrimethylene terephthalate fibers, polylactic acid fibers; polyarylate fibers; nylon 6, nylon An aliphatic polyamide fiber such as 66; an aromatic polyamide fiber such as an aramid fiber; a polyimide fiber; an acrylic fiber; a polyolefin fiber such as a polypropylene fiber and a polyethylene fiber; a synthetic fiber such as a polyurethane fiber; a glass fiber; (Fiber length) / D (fiber diameter) is 2 or more); natural fibers such as cotton and hemp; regenerated fibers such as rayon; semi-synthetic fibers such as acetate fibers; composite fibers having a core-sheath structure; Fibers can be used. These fibers may be used alone, or a plurality of these fibers may be mixed and used. Moreover, the cross-sectional shape of the fiber is not particularly limited.

  On the other hand, examples of the radioactive cesium adsorbent include ferrocyanide-based adsorbents having a ferrocyanide such as ferric ferrocyanide, potassium ferrocyanide, and ammonium ferrocyanide as a component.

  The method of applying the radioactive cesium adsorbent to the substrate is, for example, (i) a method of impregnating, spraying and applying a dispersion containing the radioactive cesium adsorbent to the substrate after manufacturing the substrate, (ii) When manufacturing a base material, the method (what is called kneading | mixing method) to which a radioactive cesium adsorbent is also mixed as a base material raw material, and a radioactive cesium adsorbent is provided simultaneously with manufacturing a base material is mentioned. Since the radioactive cesium adsorbent adsorbs radioactive cesium on the surface and inside thereof, after manufacturing the substrate so that the contact area with the radioactive cesium is increased, a dispersion containing the radioactive cesium adsorbent is applied to the substrate. The method of impregnation is particularly preferred.

  As the sheet material containing the highly water-swellable fiber, for example, an acrylic resin (which hardly exhibits water absorption) is used as a core, and a resin containing polyacrylate (which exhibits high water absorption) is used as a sheath. The sheet material which contains such a highly water-absorbing swelling fiber in part or all. More preferably, a non-woven fabric reinforced in strength, which is a laminate of a non-woven fabric containing highly water-swellable fibers and a spunbond nonwoven fabric excellent in strength, may be used.

  For these radioactive cesium adsorbing sheets, commercially available products such as “Cosmo Fresh (registered trademark) CF-4131N” and “Borane Seal (registered trademark) 600” manufactured by Toyobo Co., Ltd. may be used.

[Shielding sheet]
The shielding sheet having shielding properties will be described in detail. It is preferable that the shielding sheet having a shielding property against radiation emitted by radioactive cesium includes a single metal having a high shielding ability against α rays, β rays, and γ rays, or a metal compound containing the metal. Examples of the metal having a high shielding ability against α rays, β rays, and γ rays (hereinafter referred to as a shielding agent) include at least one kind of metal selected from barium, tungsten, and lead, and a metal compound containing the metal. Can be mentioned. By using an element having a relatively large atomic number, such as barium, tungsten, or lead, the amount of exposure from α rays, β rays, and γ rays with low energy can be effectively reduced. Examples of the metal compound having barium, tungsten, and lead as constituent elements include barium sulfate, tungsten oxide, tungsten carbide, lead oxide, and the like. In the present invention, since the element is inexpensive, it is preferable to employ barium sulfate or tungsten oxide as the metal compound. In addition, these metal compounds can be used alone or in combination. In addition, as long as it has as a main component at least 1 sort (s) of metal chosen from barium, tungsten, and lead, you may mix other components other than the above.

  It is desirable that the shielding sheet also has flexibility, and a plate made by kneading a shielding agent prepared by powdering the metal itself or a metal compound containing the metal into a base material such as rubber or elastomer having excellent strength. A flexible material in the form of a sheet is desirable. As a supplement, a plate-like or film-like material made of the metal alone or a metal compound containing the metal, or a laminate thereof may be used depending on the situation.

  As the base material of the shielding sheet, it is preferable to use a resin having excellent mechanical strength and chemical strength such as weather resistance and chemical resistance, and a material having excellent flexibility such as rubber and elastomer can be preferably used. Examples of the rubber include natural rubber, chloroprene rubber, silicone rubber, ethylene propylene rubber, ethylene propylene diene rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, and blends thereof. Examples of the elastomer include polyester, polyolefin, Examples thereof include silicone-based thermoplastic elastomers. Among these, use of rubber is desirable, and chloroprene rubber, ethylene propylene rubber, and ethylene propylene diene rubber are more preferable.

The shielding agent is desirably contained in the shielding sheet at 600 to 16000 g / m ² , more preferably 1000 to 12000 g / m ² .

  The thickness of the shielding sheet is, for example, 0.3 to 4 mm (more preferably 0.5 to 3 mm).

  Although the X-ray transmittance in a single layer of such a shielding sheet is 0.1 to 30%, the shielding effect can be further enhanced by using the shielding sheets in multiple layers.

  For the shielding sheet, for example, “Radiation shielding sheet XBW002” manufactured by Kureha Elastomer Co., Ltd. may be used.

<Embodiment 2>
The base rubber sheet 1 is desirably large and flexible enough to cover the platform of the transport truck. On the other hand, since it is desired to take measures against radioactive cesium with the shielding sheet 30 or the like in the tilt of the transport truck, the base rubber sheet 1 and the shielding sheet 30 are combined by combining the functions of the base rubber sheet 1 and the shielding sheet 30. It is also possible to form an integrally molded product.

  FIG. 3 shows a modification of the base rubber sheet 1. FIG. 3 shows an example of the base rubber sheet 1 in which the side part 1b extends from the bottom part 1a. That is, in the base rubber sheet 1, the side part 1b is extended from the bottom face part 1a, and the side part 1b is extended from the radioactive cesium adsorption sheet 2 and the pressing rubber sheet 3. The base rubber sheet 1 has both a bottom surface portion 1a and side portions 1b, and the bottom surface portion 1a has a rectangular shape, for example, in accordance with the shape of the loading platform. Therefore, a truck loading platform mat 10 is installed on the loading platform. In some cases, by raising the side portion 1b, the side portion 1b can function as the weir 4, and further, a shielding effect in the side direction is exhibited. Moreover, since the base rubber sheet 1 can be rolled up with the radioactive cesium adsorption sheet 2 and the pressing rubber sheet 3, it is efficient. It is desirable that the side portions 1b exist on the same four sides as the number of tilted surfaces of the transport truck (one front surface, two side surfaces, and one rear surface).

  In the case where the base rubber sheet 1 having such a side portion 1b extending from the bottom portion 1a is used, the side portion 1b has barium, tungsten, It is desirable that at least one kind of metal selected from lead and a metal compound containing the metal are included, but if these metals are also included in the bottom surface portion 1a, the weight of the truck bed mat 10 increases, Therefore, it is more preferable that the side portion 1b contains the shielding agent and the bottom portion 1a does not contain these metals.

  The side portion 1b may be higher than the tilt, but the height of the side portion 1b is preferably equal to or less than the height of the tilt in consideration of the weight of the side portion 1b.

  FIG. 4 shows another example of the base rubber sheet 1 having an overlap in the side portion 1b. In FIG. 4, cuts 6 are made from the four corners of the base rubber sheet 1 toward the inside of the rectangle, and the side portion 1 b is raised when the truck bed mat 10 is installed in the bed similarly to the case of FIG. 3. Thus, the shielding sheet 30 can be provided continuously from the bottom surface 1a to the front, side, and rear tilts.

  A fixing member such as a magnet may be provided on the back surface (that is, the contact surface with the tilt) of the side portion 1b in FIGS.

  The truck bed mat according to the present invention can be preferably used as a dump truck truck for transporting radioactive waste, particularly preferably a dump truck bed for transporting contaminated soil.

DESCRIPTION OF SYMBOLS 1 Base rubber sheet 1a Bottom face part 1b Side part 2 Radioactive cesium adsorption sheet 3 Holding rubber sheet 4 Weir 5, 31 Fixing member 6 Notch 10 Truck carrier mat 20 Truck 30 Shielding sheet

Claims (4)

  A rollable truck bed mat, characterized in that a radioactive cesium adsorption sheet is laminated on a base rubber sheet, and a water-permeable pressing rubber sheet is laminated on the radioactive cesium adsorption sheet.   2. The truck bed mat according to claim 1, wherein in the base rubber sheet, a side part extends from a bottom surface part, and the side part extends from the radioactive cesium adsorption sheet and the pressing rubber sheet.   The truck bed mat according to claim 1 or 2, wherein a magnet sheet is fixed to a back surface of the base rubber sheet.   The truck bed mat according to claim 2, wherein the side portion includes at least one metal selected from barium, tungsten, and lead and a metal compound containing the metal.