JP5761669B2 - How to store radioactive contaminants - Google Patents

Description

  The present invention relates to a storage method for safely storing a radioactive pollutant contaminated with a radioactive substance (for example, cesium).

  Radioactive substances (for example, cesium 137, iodine 131, etc.) released into the atmosphere due to a nuclear accident or the like fall on the ground and accumulate on the surface thereof, and the removal thereof becomes a problem. As an effective method for removing radioactive substances accumulated on the surface of the earth, a method of removing soil on the surface (for example, soil having a surface of about 5 cm) has been proposed.

  However, even if the soil on the surface is removed, the amount of removed soil becomes large, and its storage method is a problem. For example, when the removed soil is stored in a storage bag (for example, a sand bag) and buried in the ground, a new problem arises that radioactive materials leak from the storage bag and contaminate groundwater. . In order to solve this problem, for example, a storage bag may be buried in the ground via a waterproof sheet. However, radioactive materials may leak due to damage of the waterproof sheet due to long-term storage. There is.

  An object of the present invention is to provide a storage method capable of safely storing a radioactive pollutant contaminated with a radioactive substance in the ground for a long period of time.

  According to a first aspect of the present invention, there is provided a method for storing radioactive pollutants, wherein a first asphalt layer is provided in the entire area excluding a storage opening of a storage space provided in the ground, the storage space is waterproofed, and contamination with radioactive material A storage container or storage bag containing the radioactive contaminants stored therein is stored in the storage space through the storage opening, and then asphalt is placed in a gap between the storage container or storage bag stored in the storage space. These are filled into a storage lump, and then the storage opening of the storage space is filled with soil and the storage lump is covered with soil.

  Further, in the method for storing radioactive pollutants according to claim 2 of the present invention, before storing in the storage space, the storage container or storage bag is immersed in molten asphalt so that the storage container or storage bag is It is characterized by covering with a second asphalt layer.

  In the method for storing radioactive pollutants according to claim 3 of the present invention, the first asphalt layer in the storage space is formed by spraying asphalt emulsion, and molten asphalt is applied to the bottom surface of the first asphalt layer. A bottom asphalt layer is formed by flowing in.

  In the method for storing radioactive contaminants according to claim 4 of the present invention, a first waterproof sheet is disposed in the entire area of the storage space excluding the accommodation opening, and an asphalt emulsion is provided on the surface side of the first waterproof sheet. To form the first asphalt layer.

  Furthermore, in the method for storing radioactive pollutants according to claim 5 of the present invention, a second waterproof sheet is provided on the surface side of the storage lump, and the surface side of the second waterproof sheet is filled with soil and stored. The mass is covered with soil.

  According to the method for storing radioactive pollutants according to claim 1 of the present invention, the storage space is waterproofed by providing the first asphalt layer in the entire area excluding the accommodation opening of the storage space provided in the ground, and this waterproof processing Since storage containers (or storage bags) containing radioactive pollutants are stored and stored in the storage space, the first asphalt layer's waterproof function prevents leakage of radioactive pollutants into groundwater. it can. In addition, asphalt is filled in the gap between the storage containers (or storage bags) contained in the storage space and these are stored as storage lump, so that radioactive pollutants leak from the storage containers (or storage bags) Therefore, leakage of radioactive pollutants into the ground water can be more reliably prevented.

  According to the method for storing radioactive pollutants according to claim 2 of the present invention, since the storage container (or storage bag) is immersed in the molten asphalt, the storage container (or storage bag) is used as the second asphalt layer. It can be easily covered with this, so that leakage of radioactive pollutants during the transport of storage containers (or storage bags) can be reliably prevented, plus radioactive materials during storage in the ground Leakage can also be prevented.

  According to the method for storing radioactive pollutants according to claim 3 of the present invention, since the first asphalt layer is formed by spraying an asphalt emulsion, the first asphalt layer is made flexible. As a result, the occurrence of cracks in the first asphalt layer can be prevented. Further, since the molten asphalt flows into the bottom surface of the first asphalt layer to form the bottom asphalt layer, the bottom surface of the storage space 2 can be hardened to support the storage container (or storage bag). In addition, since the first asphalt layer exists below the bottom asphalt layer, even if a crack occurs in the bottom asphalt layer, the first asphalt layer penetrates into the crack due to water pressure, earth pressure, etc. Thereby, the waterproof function of the bottom asphalt layer can be maintained.

  Moreover, according to the method for storing radioactive pollutants according to claim 4 of the present invention, the first waterproof sheet is disposed in the entire area excluding the accommodation opening of the storage space, and the asphalt emulsion is provided on the surface side of the first waterproof sheet. Therefore, the first asphalt layer made of asphalt emulsion can be easily formed, and the waterproof function of the storage space can be further enhanced.

  Furthermore, according to the method for storing radioactive pollutants according to claim 5 of the present invention, the second waterproof sheet is disposed on the surface side of the storage lump, and the surface side of the second waterproof sheet is filled with soil. Therefore, a sufficient waterproof function can be provided even on the storage opening side of the storage space.

Explanatory drawing explaining the process for forming the storage space in the storage method of the radioactive pollutant according to this invention. Explanatory drawing explaining the process for accommodating the bag for storage in the storage space in the storage method of the radioactive pollutant according to this invention. Explanatory drawing explaining the process for making the storage bag into the storage lump in the storage method of the radioactive pollutant according to this invention. Explanatory drawing which shows the state which stored the bag for storage in the storage method of the radioactive pollutant according to this invention. Explanatory drawing which shows the other example of the storage method of the radioactive pollutant according to this invention.

  Hereinafter, an example of a method for storing radioactive contaminants according to the present invention will be described with reference to the accompanying drawings.

  In this method of storing radioactive pollutants, radioactive pollutants (eg, soil) contaminated with radioactive materials (eg, cesium 137, iodine 131, etc.) are contained in storage bags, and radioactive pollutants are contained. Storage bags are stored and stored in underground storage spaces (waterproofed spaces), and asphalt is used for waterproofing. In the present specification, “asphalt” is used as a concept including modified asphalt such as molten asphalt (so-called hot asphalt), bronze asphalt, rubber asphalt obtained by adding rubber to asphalt.

  As will be further described with reference to FIGS. 1 to 4, a storage space 2 for storing radioactive pollutants is provided in the ground. For example, the construction machine 4 (for example, a power shovel) is used to excavate the ground, and the storage hole 6 having a rectangular parallelepiped upper surface is formed. Then, waterproofing is applied to the entire bottom surface and peripheral side surface of the storage hole 6. Asphalt (including modified asphalt) is used as a treatment material for the waterproof treatment, and the first asphalt layer 8 is provided on the bottom surface and the peripheral side surface of the storage hole 6. For example, the first asphalt layer 8 is formed by spraying an asphalt emulsion as a modified asphalt on the bottom surface and the peripheral side surface of the storage hole 6, and the first asphalt layer 8 thus formed has flexibility, It has a sufficient waterproof function. After forming the first asphalt layer 8 in this way, molten asphalt is poured into the bottom surface of the first asphalt layer 8 to form the bottom asphalt layer 10. By forming the bottom asphalt layer 10 in this way, a double waterproof structure of the first asphalt layer 8 and the bottom asphalt layer 10 is formed at the bottom of the storage space 2, and a sufficient waterproof mechanism can be secured. Even if a crack occurs in the bottom asphalt layer 10, the first asphalt layer 8 moves and penetrates into the crack due to the surrounding water pressure and earth pressure, thereby maintaining the waterproof function of the bottom asphalt layer 10. be able to. When the storage space 2 is not large, the bottom asphalt layer 10 can be omitted.

  After providing the storage space 2 in the ground in this way, for example, radioactive contaminants are accommodated in the storage space 2 as shown in FIG. In this embodiment, for example, a sand bag 14 is used as a storage bag for storing radioactive pollutants (for example, soil contaminated with radioactive materials, incineration ash, etc.), and the radioactive pollutants are, for example, operations in which surface soil is removed. It is accommodated in the sand bag 14 at the site (or a work site where surface soil, incinerated ash, etc. are accumulated).

  Sandbag 14 containing radioactive contaminants is covered with a second asphalt layer. For example, the second asphalt layer can be formed by immersing the entire sound bag 14 in molten asphalt (so-called hot asphalt), and by soaking the sand bag 14 in the molten asphalt, The sand bag 14 can be provided with a waterproof function, can facilitate the adhesion of the sand bag 14 to be described later, and can enhance the adhesion thereof. In addition, the radioactive contamination from the sand bag 14 can be surely leaked. Can be prevented.

  Thus, the sandbag 14 covered with the second asphalt layer is transported to the storage space 2 formed as described above and accommodated therein. The sand bag 14 can be transported on a vehicle such as a truck. For example, the sand bag 14 can be transported using a lift transport device 16 as shown in FIG. And can be transported by various known methods.

  In the illustrated example as an example of the conveying method in FIG. 2, the lift conveying device 16 is provided so as to convey the sand bag 14 through the work site (not shown) from which the surface soil is removed and the storage space 2. The lift conveyance device 16 includes a plurality of support columns 18, the plurality of support columns 18 are provided on the ground at predetermined intervals, and a conveyance wire 20 is stretched on the support columns 18 through the work site and the storage space 2. Is done. Pulleys are rotatably mounted on the support pillars 18, and the transport wire 20 is movably supported by these pulleys and provided in an annular shape, but in FIG. 2, transport for transporting the sandbag 14 to the storage space 2. Only the forward side 22 of the wire 20 is shown, and this forward side 22 is moved in the direction indicated by the arrow 24.

  The conveying wire 20 is provided with a suspending tool 22 for suspending the sand bag 14, and the suspending tool 22 is configured such that its suspending portion can be switched between a locked state and a released state. When the hanging portion of the hanging portion 22 is in the locked state, the annular hooking portion of the sand bag 14 (for example, formed by a rope that tightens the opening portion of the sand bag 14) can be locked, In some cases, the annular hanging portion locked to the hanging portion can be detached from the hanging portion.

  A coating formation area 26 is provided between the work site (not shown) and the storage space 2, and it is desirable to provide this coating formation area 26 near the work site. In this embodiment, support legs 28 are provided in the coating formation region 26, and the heating pot 30 is supported on the support legs 28. A heating burner 32 is provided below the heating pot 30, and the heating pot 30 is heated by the heating burner 32. Asphalt is placed in the heating pot 30, and the asphalt is melted by the heat from the heating burner 32, and thus the molten asphalt 31 is produced.

  The radioactive pollutant is accommodated in the sand bag 14 at the work site, and the opening portion of the sand bag 14 accommodated in this manner is closed with a rope, and when this is closed, an annular hook portion is formed. The sand bag 14 containing radioactive contaminants is locked to a hanging tool 22 (specifically, a hanging part in a locked state) at the work site, and is directed to the storage space 2 in the direction indicated by the arrow 24. Are transported. Then, in the coating formation area 26 in the middle of the conveyance, the sand bag 14 is immersed in the molten asphalt 31 in the heating pot 30, and is thus immersed so that the entire sand bag 14 is covered with the second asphalt layer, and is thus covered. Later, it is transported to the storage space 2.

  When the sand bag 14 is conveyed to above the storage space 2, the suspended portion of the hanging tool 22 is released. Thus, the annular hooking portion of the sand bag 14 is detached from the hanging portion of the hanging tool 22, and the conveyed sand bag 14 falls from the hanging tool 22 and is stored in the storage space 2.

  In this example, the sand bag 14 is immersed in the molten asphalt 31 while being transported to the storage space 2, but instead of such an example, a coating formation area 26 is provided at the work site. 26 is provided with a heating pot 30 to form a molten asphalt 31, the sand bag 14 is immersed in the molten asphalt 31 at the work site, and the sand bag 14 covered with the second asphalt layer is moved to the storage space 2 by the lift conveying device 16. You may make it convey. Alternatively, the sand bag 14 immersed in the molten asphalt 31 at the work site may be placed on the vehicle and conveyed to the storage space 2.

  After the sand bag 14 is accommodated in the storage space 2 as described above, as shown in FIG. 3, the molten asphalt 34 is injected into the storage space 2, and the molten asphalt 34 is poured into the gap between the sand bags 14. Make it disappear. At this time, if molten asphalt (so-called hot asphalt) is poured in a state where a large number of sandbags 14 are accommodated in the storage space 2, there is a risk that a gap will remain between the sandbags 14. It is desirable to inject molten asphalt in a state of being stacked in three layers, and repeatedly carry out the storage of the sand bag 14 into the storage space 2 and the injection of molten asphalt into the storage space 2. When molten asphalt is injected in this way, the molten asphalt functions like an adhesive, and the sand bag 14 covered with the second asphalt layer is bonded via the molten asphalt, and the molten asphalt is hardened, and a large number of The sandbag 14 becomes one lump.

  When the sandbag 14 is stored and the molten asphalt is injected repeatedly as described above, the gap between the sandbags 14 is filled with the molten asphalt, and the molten asphalt into which a number of sandbags 14 stored in the storage space 2 are injected. Thus, one large storage mass 36 is obtained. In such a state of the storage lump 36, the sand bag 14 covered with the second asphalt layer is further covered with molten asphalt to become one lump, and is accommodated in the storage space 2 in a very stable state. It has sufficient strength to withstand external water pressure and earth pressure.

  After the sand bag 14 accommodated in the storage space 2 is made into a storage lump 36 by the molten asphalt 34, as shown in FIG. 4, soil 38 is put into the storage opening 7 of the storage space 2, and the upper side of the storage lump 36 is soiled. Cover with 38. Thereafter, the accommodation opening 7 of the storage space 2 is covered with the waterproof sheet 40 so as to cover the soil 38, and the storage opening 2 of the storage space 2 is waterproofed in this way to allow the groundwater to flow into the storage space 2. To prevent.

  Then, this waterproof sheet 40 is covered with soil and returned to its original state. In this way, the sand bag 14 is stored in the ground as a single storage lump 36 with asphalt. In such buried storage areas where a large number of storage spaces 2 are provided, sandbags 14 containing radioactive pollutants are buried in the ground, and therefore, as shown in FIG. By installing the solar power generation equipment 44, its effective use can be achieved.

  In the example described above, the waterproof sheet 40 is provided in the accommodation opening 7 of the storage space 2. However, such a waterproof sheet is also provided on the bottom surface and the peripheral side surface of the storage hole 6, It is desirable to spray the asphalt emulsion on the surface side of the prevention sheet on the bottom surface and the peripheral side surface. By spraying through the prevention sheet in this way, the construction of the asphalt emulsion becomes easy and the waterproof function is provided by the waterproof sheet. Can be increased.

  In the embodiment described above, the sand bag 14 as a storage bag is used to store radioactive pollutants. Instead of such a storage bag, for example, a cubic or cuboid storage container is used. You may make it use. Referring to FIG. 5, as such a storage container, for example, a synthetic resin container 52 (for example, a container main body that stores radioactive contaminants and a lid that closes an opening of the container main body) is provided. Can be used. Even when such a storage container is used, as described above, the synthetic resin container 52 containing radioactive contaminants is immersed in, for example, molten asphalt and covered with the second asphalt layer, and then the same as described above. In the storage space 2.

  Each time the synthetic resin container 52 is accommodated in the storage space 2 and stacked in, for example, two to three stages, the molten asphalt 34 is injected in the same manner as described above so that the gap between the synthetic resin containers 52 is eliminated. The synthetic resin container 52 accommodated in this manner is used as one storage lump 36A, and thus the storage lump 36A is used, so that the synthetic resin container 52 can be stably embedded and stored in the ground. In addition, after the synthetic resin container 52 is made into the storage lump 36A, it returns to the original state in the same manner as described above.

  When using such a storage container, for example, by applying lead coating to the inner surface of the container, or by arranging a lead sheet on the inner surface, leakage of radiation to the outside can be suppressed. By using such a storage container, it becomes possible to store contaminants that are strongly contaminated with radioactive products. In order to suppress the leakage of radiation to the outside, lead may be mixed into the asphalt, and the first asphalt layer 10 covering the storage space 2 may be formed using the lead mixed asphalt. The storage lump 36A may be formed using mixed asphalt.

  As mentioned above, although the Example of the storage method of the radioactive pollutant according to this invention was described, this invention is not limited to this storage method, A various deformation | transformation thru | or correction | amendment are possible without deviating from the scope of the present invention.

  For example, in the embodiment described above, the storage hole 6 is excavated in the ground to provide the storage space 2, but a waste mine or the like can be used as the storage hole 6.

2 Storage space 6 Storage hole 8 First asphalt layer 14 Sand bag (storage bag)
16 Lift transfer device 20 Transfer wire 22 Suspension tool 26 Cover formation area 31, 34 Molten asphalt 36, 36A Storage lump 40 Waterproof sheet 52 Synthetic resin container (storage container)

Claims (4)

A first asphalt layer is provided over the entire area of the storage space except the storage opening in the ground to waterproof the storage space and melt the storage container or storage bag containing radioactive contaminants contaminated with radioactive material. After immersing in asphalt and covering the storage container or storage bag with the second asphalt layer, the storage container or storage bag is stored in the storage space through the storage opening, and then stored in the storage space. Asphalt is filled in the gap between the stored storage container or storage bag to form a storage lump, and then the storage opening is filled with soil and the storage lump is covered with soil. How to store radioactive pollutants. Wherein the first asphalt layer of the storage space is formed by spraying an asphalt emulsion, claim 1, characterized in that the bottom asphalt layer is formed by flowing the molten asphalt on the bottom surface of the first asphalt layer How to store radioactive contaminants as described in 1. Claim 2, wherein the first waterproof sheet disposed over the entire region excluding the accommodating opening of the storage space, and forming the first asphalt layer by spraying asphalt emulsion on the surface side of the first waterproof sheet How to store radioactive contaminants as described in 1. 4. The radioactive pollutant according to claim 3 , wherein a second waterproof sheet is disposed on a surface side of the storage lump, the soil is filled on the surface side of the second waterproof sheet, and the storage lump is covered with soil. Storage method.

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