JP6650291B2 - How to store radioactive waste - Google Patents

Description

  The present invention relates to a method for storing radioactive waste, for example, to a method for intermediately storing low-level radioactive waste generated by decontamination treatment or the like.

  Radioactive waste must be treated appropriately according to the concentration of radioactive material. Regarding the final disposal of waste having a high concentration of radioactive substances or waste having a landfill standard value or less, many techniques have been proposed (for example, see Patent Documents 1 and 2). The technology described in Patent Literature 1 disposes a leachate formed on the ground and provided with a guide groove for guiding leachate on the bottom surface and a leachate disposed in the guide groove and flowing from the guide groove outside the facility. Radioactive material adsorbing member (crushed stone) that is made using a drain pipe for guiding the water and an adsorbent that adsorbs the radioactive material contained in the leachate, and is provided in the flow path of the leachate until it is discharged outside the facility Zeolite, leachate basin (filter material), partition weir).

  The technology described in Patent Literature 2 has a substantially cylindrical structure in which a radioactive substance is stored in a cask storage room that is provided with a loading / unloading port and at least a pair of intake / exhaust ports in a mountain or underground, and is constructed in a tunnel shape by concrete walls. This is a technology related to a radioactive material storage facility that stores a cask in a shape. In this radioactive substance storage facility, casks are arranged such that the shortest spatial distance between the surface of the cask and the concrete wall surface of the cask storage room is 0.45 times or more the diameter of the cask.

JP 2014-81272 A JP 2007-71771 A

  As mentioned above, many technologies have been proposed for the final disposal of high-concentration radioactive waste and waste below the landfill standard value.In recent years, low-level radioactive waste generated by decontamination treatment and the like has been developed. Because of the necessity of treatment, it is urgently necessary to develop technologies for appropriate treatment of intermediate storage of low-level radioactive waste. At present, low-level radioactive waste generated by decontamination and the like is packed in a bag of a predetermined volume, accumulated, and then transported to a facility for intermediate storage and stored.

  However, even if the concentration of radioactive material is low, it is still radioactive waste. When constructing a storage facility, consider the impact on the surrounding environment as well as understand the surrounding residents. Must get.

  Therefore, land acquisition for constructing a storage facility for radioactive waste is not easy, and even if a wide storage area is set, only a part of the area may be used. The construction of an intermediate storage facility for low-level radioactive waste is an urgent matter, and if no processing can be carried out until all of the planned storage areas can be stored, there is a need to process low-level radioactive waste promptly. I can't respond.

  Therefore, a radioactive waste storage facility will be constructed using only the areas where radioactive waste can be stored, such as with the consent of the residents in the vicinity, and areas where radioactive waste can be stored. Each time the area expands, it is necessary to sequentially store radioactive waste in the area. As a method for storing the radioactive waste by dividing the storage area into a plurality of areas, as shown in FIG. 4, it is conceivable to construct an earth dam and sequentially construct a storage section.

  In the method for storing radioactive waste shown in FIG. 4, a soil dam 100 is constructed in an area where land acquisition is possible in a storage area, and a water-impervious sheet 40 is placed in the storage unit 10 surrounded by the soil dam 100. Expand and store the radioactive waste 11. Then, with the progress of land acquisition, a new earth dam 100 is constructed in the same procedure to store the radioactive waste 11.

  However, in the method for storing radioactive waste shown in FIG. 4, it is necessary to construct the earth dam 100, and the volume of the storage unit is reduced by the amount of the earth dam 100. Further, the earth dam 100 may not be able to be constructed due to conditions such as topography and the like, and it cannot be said that all of the planned storage areas can be effectively utilized.

  The present invention has been proposed in view of the above circumstances, and in a storage area for radioactive waste, a storage unit is sequentially constructed for each area where radioactive waste can be stored, and a radioactive waste is constructed. An object of the present invention is to provide a method for storing radioactive waste, which can efficiently utilize the entire area to be stored by storing the waste.

The method for storing radioactive waste according to the present invention has the following features to achieve the above object. That is, the radioactive waste storage method according to the present invention is a method for storing the radioactive waste in the radioactive waste storage area, and the radioactive waste can be stored in the storage area. Providing a partition wall standing upright in a substantially vertical direction by combining a plurality of wall bodies in accordance with the boundary shape of the storage unit so as to surround the storage unit that has become a partition wall; A formwork is installed at a predetermined interval from, a concrete is poured between the section wall and the formwork, a step of erecting the filled concrete wall, and a bottom surface on the storage section side surrounded by the section wall and A step of spreading a seepage control sheet on the storage part side of the filling concrete wall, a step of providing a water permeable layer on the bottom face of the storage part side where the seepage control sheet is spread and a storage part side of the filling concrete wall, and The process of storing waste Wherein the storage is carried out each step for each reservoir became feasible, it is characterized in performing the storage processing in the storage schedule area.

  In the method for storing radioactive waste, the partition walls can be constructed by combining precast concrete walls. That is, the precast concrete wall is formed in an appropriate size, and by combining these, a partition wall having a desired shape and size can be constructed.

As described above, the partition wall is installed according to the boundary shape of the storage unit. That is, if the boundary shape of the storage unit is straight, a linear partition wall is installed, and if the boundary shape of the storage unit is bent, the partition wall is also bent and installed.

  According to the method for storing radioactive waste according to the present invention, a partition wall that stands substantially vertically is erected so as to surround the area in which the storage of radioactive waste can be performed in the storage area. At the same time, by installing reinforcement equipment and impermeable equipment, storage of radioactive waste can be started sequentially in areas where land acquisition was possible before storage can be performed in all storage areas. .

  In addition, since the earth dam is not constructed, the volume of the storage unit is not reduced by the amount of the earth dam, and the storage unit can be used most effectively. In addition, the construction time can be shortened and the construction cost can be reduced by constructing the partition wall with precast concrete. Furthermore, by installing the partition wall in accordance with the boundary shape of the storage section, it is possible to construct a storage section of an appropriate shape according to the situation of the storage area, and in this regard, the storage area can be maximized. It can be used as effectively as possible.

Explanatory drawing which shows the outline | summary of the storage method of the radioactive waste which concerns on embodiment of this invention. The schematic diagram of the storage structure constructed by the radioactive waste storage method according to the embodiment of the present invention. Explanatory drawing which shows the procedure of the storage method of the radioactive waste which concerns on embodiment of this invention. Explanatory drawing which shows the outline of the conventional storage method of radioactive waste.

  Hereinafter, a method for storing radioactive waste according to an embodiment of the present invention will be described with reference to the drawings. 1 to 3 illustrate a method for storing radioactive waste according to an embodiment of the present invention. FIG. 1 is an explanatory view showing an outline of a method for storing radioactive waste, and FIG. 2 is a method for storing radioactive waste. FIG. 3 is a schematic view of a storage structure constructed by the method shown in FIG. FIG. 4 is an explanatory diagram showing an outline of a conventional method for storing radioactive waste.

<Summary of radioactive waste storage method>
The radioactive waste storage method according to the embodiment of the present invention is a technique that can be suitably applied when constructing an intermediate storage facility for low-level radioactive waste generated in a decontamination operation or the like. As shown in FIG. 1, the method for storing the radioactive waste 11 does not involve simultaneously constructing the storage unit 10 over the entire area to be stored, but instead for each storage unit 10 in which the storage of the radioactive waste 11 can be performed. It is characterized in that the storage unit 10 is constructed by dividing the storage unit 10 into a plurality of times, and that a partition wall 20 that stands in a substantially vertical direction is used as a wall surrounding the storage unit 10 instead of an earth dam.

  Specifically, as shown in FIG. 3, a step of providing the partition wall 20, a step of erection of the concrete-filled concrete wall 30 on the inner surface side of the partition wall 20, and a waterproof sheet 40 on the inner surface side of the storage unit 10 , A step of providing a water-permeable layer 50 on the inner surface side of the water-blocking sheet 40, and a step of storing the radioactive waste 11 in the storage unit 10. By performing each process for each storage unit 10 in which storage can be performed, storage processing can be sequentially performed over the entire storage area. That is, in the present invention, the radioactive waste 11 can be temporarily stored in the storage area without any change in the basic structural plan for the storage facility of the radioactive waste 11.

<Each process>
Each step of the method for storing radioactive waste 11 according to the embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the storage units 10 capable of storing the radioactive waste 11 are constructed one by one. However, the storage units 10 are constructed at a plurality of locations in the same planned storage area. Is also good.

<Compartment wall>
In order to construct a storage facility for the radioactive waste 11, first, the radioactive waste 11 was erected in a substantially vertical direction so as to surround the storage unit 10 in which the radioactive waste 11 could be stored in the storage area. A partition wall 20 is provided (FIG. 3B). Prior to this step, it is preferable to spread the water-blocking sheet 40 on the bottom surface of the storage unit 10 (FIG. 3A). Further, it is preferable that the partition wall 20 is constructed by combining precast concrete walls. As a wall for constructing the partition wall 20, for example, a precast concrete block material can be used.

  The block material of the present embodiment includes a main body 21 and a protruding portion 22 provided to protrude from one side of the main body 21, and has a desired height and area by combining the blocks vertically and horizontally. The partition wall 20 can be constructed. Since the block material is made of precast concrete, it is possible to manufacture a block material having an optimal shape and size according to the outer peripheral shape and volume of the storage unit 10, the construction environment, and the like, and by appropriately combining each block material. The appropriate partition wall 20 can be constructed according to the height and the boundary shape of the storage unit 10 to be constructed.

  In addition, it is preferable to apply the leveling concrete 60 and the base concrete 70 on the ground which is the base portion of the block material. The base wall 70 and the protruding portion 22 allow the partition wall 20 to stably stand up. The width, thickness and the like of the base concrete 70 can be appropriately set according to the partition wall 20 to be constructed. Further, by applying a design to the outer surface of the partition wall 20, the appearance can be improved.

<Solid concrete wall>
After the partition wall 20 is provided, the middle concrete wall 30 is erected on the storage section 10 side (inside) of the partition wall 20 (FIG. 3C). In order to construct the filled concrete wall 30, a formwork 80 is installed at a predetermined distance from the partition wall 20 on the storage section 10 side (inside) of the partition wall 20, and the space between the partition wall 20 and the formwork 80 is set. Concrete can be poured into the area. For example, a connection hole 23 is provided in the protruding portion 22 of the block material, and one end of the separator 81 is attached to the connection hole 23 and a mold 80 is attached to the other end of the separator 81, so that a predetermined distance from the partition wall 20 is maintained. The mold 80 can be installed at a distance.

  In this way, by laying the middle-filled concrete wall 30 on the storage unit 10 side (inside) of the partition wall 20, the strength of the partition wall 20 is increased. Even if pressure is applied, the partition wall 20 can be prevented from collapsing or being damaged. Furthermore, since the filled concrete wall 30 functions as a radiation shielding wall, when the low-level radioactive waste 11 is stored in the storage unit 10, the effect of reducing the exposure to the surrounding environment can be enhanced.

<Water barrier sheet>
In addition, in order to prevent water leakage from the storage unit 10, a waterproof sheet 40 is spread on the bottom surface of the storage unit 10 surrounded by the partition wall 20 and on the storage unit 10 side of the filling concrete wall 30 (FIG. 3D). ). Before the partition wall 20 is provided, the water-impervious sheet 40 is spread on the bottom surface of the storage unit 10, the partition wall 20 is provided thereon (FIG. 3 (a)), and the filling concrete wall 30 is erected. After that, the water impermeable sheet 40 is generally spread on the storage section 10 side of the filled concrete wall 30. That is, the step of extending the water-blocking sheet 40 can be divided into two steps before the construction of the partition wall 20 and after the construction of the middle-filled concrete wall 30.

  The impermeable sheet 40 is generally used in civil engineering work, and its material, thickness, and the like are appropriately selected and used according to the properties of the radioactive waste 11 to be stored. When a member that penetrates the waterproof sheet 40 is provided, a water-swellable waterproof sealing material is applied to the penetrating portion.

<Permeable layer>
Further, in order to remove rainwater or the like that accumulates in the storage unit 10, a water-permeable layer 50 is provided on the bottom surface of the storage unit 10 on which the water-blocking sheet 40 is spread and on the storage unit 10 side of the filled concrete wall 30 (FIG. 3 (f)). )-(H)). The permeable layer 50 may be appropriately selected from those commonly used in the construction of retaining walls and embankments, for example, permeable mats and crushed stones. The material and thickness of the water-permeable layer 50 are appropriately selected and used according to the properties of the radioactive waste 11 to be stored. In addition, drainage such as embedding a drain pipe 51 in a permeable layer 50 provided on the bottom surface of the storage unit 10 is performed, and rainwater or the like is collected at one place by the drainage so that drainage (for example, pump-up) can be performed. Is preferable.

<Storage of radioactive waste>
When the storage section 10 of one section is completed by the above-described steps, embankment is performed in the storage section 10 to store the radioactive waste 11 (FIGS. 3G and 3H). At this time, it is preferable that a sheet-like reinforcing material 91 is interposed between the upper and lower embankment layers, and a form member 92 is provided at an end of the embankment. In the present embodiment, a grid belt 94 is connected to a connection fitting 93 provided at an end of the separator 81. With such a structure, the embankment layer can be self-supported, and the embankment layer can be stacked by performing sufficient compaction. Therefore, deformation of the embankment layer can be suppressed to a minimum.

<Construction of storage units in the entire planned storage area>
The above-described steps are performed for each of the storage units 10 that can be stored, and the radioactive waste 11 is stored in the storage area. In the construction of the storage units 10 in the storage scheduled area, the storage units 10 do not necessarily have to be adjacent to each other, and the storage units 10 in which storage can be performed may be separated. That is, the storage units 10 may be sequentially constructed when storage in the storage scheduled area where the construction has not been completed can be performed. When the storage unit 10 is sequentially constructed, if the planned storage area where the construction is not completed is surrounded by the partition wall 20, the storage in the planned storage area will be performed when the storage can be performed. You can start immediately. Further, in the storage step (filling step) of the radioactive waste 11, it is not always necessary to use the above-described members, and in the present invention, the radioactive waste may be stored by a general filling step.

<Others>
It is preferable to perform an appropriate process (for example, ground improvement) in advance in accordance with the soil properties and the like of the construction site of the storage unit 10. In addition, when storing (filling) radioactive waste, it is possible to use a remotely controllable heavy machine so that the storage operation can be performed without an operator entering the storage unit 10. preferable. By performing the storage operation by remote control, it is possible to carry out safe storage operation while minimizing the amount of exposure of the workers.

DESCRIPTION OF SYMBOLS 10 Storage part 11 Radioactive waste 20 Partition wall 21 Main part 22 Projection part 23 Connection hole 30 Filled concrete wall 40 Waterproof sheet 50 Permeable layer 51 Drain pipe 60 Leveling concrete 70 Base concrete 80 Formwork 81 Separator 91 Reinforcement 92 Formwork member 93 Connection fitting 94 Grid belt 100 Earth dam

Claims (2)

A method for storing radioactive waste in an area where radioactive waste is to be stored, comprising:
A plurality of wall bodies are combined in accordance with the boundary shape of the storage unit so as to surround the storage unit in which the storage of the radioactive waste can be performed in the storage planned area, thereby being set up substantially vertically. Providing a partition wall;
A formwork is installed on the storage section side of the partition wall at a predetermined distance from the partition wall, concrete is poured between the partition wall and the formwork, and a filled concrete wall is erected. Process and
A step of spreading a water-impervious sheet on the storage section side of the storage section side surrounded by the partition wall and the storage section side of the filled concrete wall,
A step of providing a water-permeable layer on the storage section side of the storage section side where the water-impervious sheet is stretched and the storage section side of the filled concrete wall,
Storing the radioactive waste in the storage unit,
A method for storing radioactive waste, comprising: performing each of the above-described steps for each storage unit in which the storage can be performed, and performing storage processing in the storage-scheduled area.   The method according to claim 1, wherein the partition wall is constructed by combining a wall made of precast concrete.

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