JP6021337B2 - Construction method of storage structure for radioactive material-containing materials - Google Patents

Description

The present invention relates to a method for constructing a storage structure for radioactive material-containing materials, and it treats waste and decontaminated soil containing various radioactive materials that are diffused from the site to the vicinity and a wide area due to a nuclear power plant accident. In this regard, the present invention relates to a method for constructing a storage structure for radioactive material-containing materials that can quickly build a storage place where they can be stored and that can store them safely.

  Conventionally, a radioactive waste treatment and disposal measure and a nuclear facility decommissioning measure called back-end measures have been studied and implemented in part. These radioactive wastes should be stored and stored in final disposal sites and storage facilities that are well-defined in terms of storage form and location according to the radioactive material (nuclide) and radiation level, and have a permanent storage system. It has become.

  However, an unprecedented nuclear power plant accident occurred due to the Great East Japan Earthquake that occurred on March 11, 2011. This accident caused the radioactive material to diffuse around the power plant and over a wide area. In order to prevent external exposure due to these radioactive substances, the government has published guidelines and guidelines on decontamination and handling of objects contaminated with radioactive substances in Fukushima Prefecture and other regions (non-patent literature). 1, 2).

  The applicant possesses many technologies for membrane materials, sheets, and the like that are water shielding structures in a general waste disposal site facility (Patent Document 1).

  However, we have not experienced such accidents in the past, and materials containing radioactive materials treated as waste (hereinafter referred to as radioactive material-containing materials) to deal with such serious accidents. In the past, there was no technology or system that could satisfy the above guidelines for storage facilities or disposal sites.

JP 2007-330853 A

Ministry of the Environment, “Policy for Disposal of Disaster Waste in Fukushima Prefecture”, June 23, 2011 Nuclear Emergency Response Headquarters, “Guidelines for Decontamination Implementation by Municipalities”, August 26, 2011

  Conventional radioactive waste disposal sites are premised on the permanent storage of radioactive waste, and the ash generated from the incineration of removed soil and combustible materials caused by emergency work such as restoration or decontamination as in this case. (Main ash, fly ash), treated sludge generated by water treatment of radioactively contaminated water, radioactively-contained thinned wood and materials containing radioactive materials such as plants and rice straw, but still final storage facilities, etc. The current policy is not finalized. For this reason, it is necessary for the government and the like to urgently secure a facility that can temporarily and safely store radioactive material-containing materials that are generated over time.

  In addition, the above guidelines and guidelines merely specify the specifications required for temporary storage of radioactive material-containing materials, and no specific storage structure and storage method are shown.

  On the other hand, the applicant possesses a technique using a membrane material that is effective as a water shielding purpose or a blocking material for various pollutants in a general waste disposal site as disclosed in Patent Document 1, but this time In order to construct a facility for storing such radioactive material-containing materials, it has never been considered to integrate existing technologies in a complex manner.

  As a storage place for these radioactive material-containing materials, storage at the existing general waste final disposal site is considered. In this case, for example, a radioactive material-containing material that is carried in a predetermined amount in a final disposal site for general waste, such as one day (daily in this case), for example, can be stably prevented from leaking radioactivity to the outside. It is required to be accommodated in the venue in a state. Therefore, it is necessary to provide a structure and storage structure that meet the above specifications in daily storage work of radioactive material-containing materials. Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, meet the current request, can be constructed quickly and easily, and in the storage of radioactive material-containing materials that are brought in every day, The purpose is to provide a storage facility for radioactive material-containing materials that meets specifications and ensures safety.

In order to achieve the above-mentioned object, the present invention lays a bottom impermeable layer on the entire bottom surface of a space for storing a radioactive substance-containing material, and expands the folded net on the bottom impermeable layer to assemble the interior. Filled with earth and sand to form a box-like wall, and the box-like wall is connected in a row to be self-supporting radiation shielding wall that partitions a part of the side of the space that can be filled by storage work for a unit period surrounds to the accommodation space is formed by the in the accommodation space to accommodate side by side a plurality of the bag filled with radioactive material contained material, after storage work unit period, the upper surface of the stowed bag with covers, closing the remaining side with the radiation shield wall, separates the said housing space and an external space where the bag body is stored in each storage work unit period, further the receiving space of the bag Store the bag in the upper layer, up to a predetermined number of steps After layer complete, covering the entire accommodating space and said radiation shield wall in the outermost layer of the cover, characterized in that constructing a storage structure of the radioactive substance-containing material.

The bottom water-impervious layer preferably includes a water-impervious sheet as a base layer, and a cover soil layer is laminated on the base layer .

Said radiation shield wall is to install a precast concrete wall, it is preferable to form in combination with further prior Symbol box Jokabetai. The box-like wall body is folded and attached along the inner surface of the mesh body in a folded state, and the nonwoven fabric is stretched along the inner surface of the mesh body in an unfolded and assembled state. It is preferable to be in a state that is achieved.

  It is preferable that the covering body is constructed by laying a steel plate on the upper surface of the bag body and laminating a covering layer on the steel plate.

  As the outermost layer covering body, it is preferable to use a water shielding sheet that covers the uppermost surface of the laminated bag body and the radiation shielding wall body.

  Or it is preferable that the outermost layer covering is a membrane-structured roof that covers the uppermost surface of the stacked bags and the radiation shielding wall with its upper space.

  According to the configuration of the present invention described above, the storage structure of the radioactive substance-containing material can be quickly constructed, and thereafter, the daily storage work of the radioactive substance-containing material is performed in a safe state, and the safety of the storage state is improved. There is an effect that it can be secured.

An example of a method for constructing a storage structure of the radioactive substance-containing material of the present invention, a schematic perspective view showing an internal structure overall structure partially cut devoid of constructed storage structure. Sectional drawing which showed the storage structure shown in FIG. 1 along the II-II sectional line. The fragmentary sectional view which expanded and showed the site | part shown in FIG. The schematic perspective view which showed the example of the use condition of the box-shaped wall used for this invention. The schematic perspective view which showed the usage condition example of the bag used for this invention. The schematic perspective view which showed the storage state of the bag body in the process of a unit period in the storage structure constructed | assembled by this invention , and the completion state of the same day covering soil. FIG. 7 is a work state and storage structure explanatory diagram showing a work state from the start to the end of the storage work shown in FIG. 6 and a finally completed storage structure; Sectional drawing which showed the other Example (membrane surface structure roof) of the covering in the storage structure of this invention. The schematic perspective view which showed the state which expand | deployed the membrane surface structure roof shown in FIG. 8 according to the process. Sectional drawing which showed the other Example of the radiation shielding wall in the storage structure of this invention.

Hereinafter, the storage structure by method of constructing a radioactive substance-containing material of the present invention, for example in the form of building in general waste final disposal hall storing radioactive material-containing material, reference to the accompanying drawings for the following several embodiments I will explain. The radioactive material-containing material stored in the bag is the removed soil generated by emergency work such as decontamination, ash (main ash, fly ash) generated by incineration of combustible materials, water of radioactively contaminated water The treatment sludge generated by the treatment, radioactively-contaminated thinned wood, vegetation, rice straw and the like containing a wide range of radioactive substances are widely included, and are not limited to those described in the following examples. In addition, the storage location is not limited to the general waste final disposal site, and the storage of radioactive material-containing materials shall be promoted according to the following storage procedure within the site for storing radioactive material-containing materials partitioned as necessary. Can do.

[Temporary storage structure for incineration ash and dewatered sludge contaminated with radioactive cesium]
Among the radioactive cesium released into the atmosphere ^{(134 Cs, 137 Cs),} 137 Cs is the artificial nuclide half-life of about 30 years, long-term storage system is required. However, incineration ash incinerated waste contaminated with radioactive cesium as a radioactive material-containing material is constantly generated in restoration work. There is a general waste final disposal site as an existing facility that can accept them. In addition, when radioactive cesium is contained in sewage, etc., it is necessary to collect and store dewatered sludge, etc., which is a by-product of the sewage treatment plant. Also in these cases, the method for constructing the radioactive substance-containing material of the present invention functions effectively in a predetermined storage site secured in the sewage treatment plant.

Hereinafter, an example of a method for constructing a storage facility in a general waste final disposal site for storing incinerated ash contaminated with radioactive cesium will be described with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view showing the internal structure of a storage structure constructed by the method for constructing a radioactive substance-containing material of the present invention, with a part of the overall structure cut away. 2 is a cross-sectional view taken along the line II-II in FIG. As shown in FIG. 1 and FIG. 2, the radioactive substance-containing material storage structure 1 of the present invention has a main structure in which a large number of bags 2 filled with a radioactive substance-containing material are arranged on the bottom impermeable layer 10. The storage space 3 to be stacked and stored, and the side of the storage space 3 (details will be described later with reference to FIG. 6) partitioned so as to store the bag body 2 carried in during the set unit period are surrounded. The radiation shielding wall body 20 constructed by laminating the box-shaped wall bodies 21 at a predetermined height and the upper surface of the bag body 2 of each layer in the accommodation space 3 are covered and laminated with the radiation shielding wall body 20. A covering body 30 that separates the uppermost surface of the housing space 3 from the external space 4 is provided. Hereinafter, specific materials, structures and the like constituting these will be described. Although the unit period is preferably one day from the actual situation of the waste treatment process, two or more days can also be set as the unit period from the waste treatment capacity and transport capacity.

As shown in FIG. 1, the radioactive substance-containing material storage structure 1 constructed according to the present invention causes ground subsidence even in a general waste final disposal site or the like due to a sufficient flat area and a predetermined loading load. It will be installed where there is no ground. As described later, the radioactive substance-containing material is packed and filled in a flexible container bag (hereinafter, the bag body 2 or the abbreviated flexible container bag 2 is used synonymously) which is a bag body 2 of a predetermined volume. Stored. In the present invention, the flexible container bags filled with the contents (radioactive substance-containing material) and having a substantially cylindrical shape are arranged in the storage space that can be stored for the amount that is loaded in one day, in the vertical and horizontal directions, and according to the progress of the process. It is further laminated on the upper layer. First, the configuration of the bottom impermeable layer 10 laid on the surface on which the flexible container bag 2 is laminated will be described.

(Structure of bottom impermeable layer)
FIG. 3A is a partially enlarged view showing a part (III (a)) surrounded by a circle in FIG. 2 in an enlarged manner. As shown in the figure, a high density polyethylene (HDPE) sheet, which is a synthetic resin, is used as the water shielding sheet 11 of the main configuration of the bottom surface water shielding layer 10 in this embodiment. The sheet thickness is preferably about 1.0 to 3.0 mm in consideration of durability. As the material of the water shielding sheet 11, as a synthetic resin other than HDPE, medium density polyethylene (MDPE), low density polyethylene (LDPE), vinyl chloride resin (PVC), polyurethane (PU), ethylene-vinyl acetate copolymer ( EVA) and the like can be used, and vulcanized rubber-based ethylene-propylene-diene copolymer (EPDM) and the like can be used in addition to the synthetic resin system. The water-impervious sheet 11 is welded while laying a sheet having a predetermined width in the longitudinal direction to form a durable planar sheet whose entire surface retains water-imperviousness.

Protection mats 12 are laid on both surfaces of the water shielding sheet 11 for the purpose of protecting the water shielding sheet 11. As this protective mat 12, a polyethylene terephthalate (PET) nonwoven fabric (1000 g / m ² ) is used in this embodiment. The two protective mats 12 are laminated so that the water shielding sheet 11 is sandwiched therebetween. Other materials for the protective mat 12 include polyethylene (PE) and polypropylene (PP). Depending on the situation in contact with each surface of the water shielding sheet 11, it is also preferable to use a protective mat in which bentonite is sandwiched between upper and lower nonwoven fabrics so that a thin layer is formed only on one surface of the water shielding sheet 11.

  Further, a cover layer 13 is formed on the upper surface of the upper protective mat 12 (or the water shielding sheet 11 when the protective mat 12 is used only on the lower side). This covering layer 13 is preferably about 20 cm to 80 cm in thickness so as to obtain a radiation shielding effect on the ground side and to protect the water shielding sheet 11 from the load when the flexible container bag 2 is installed.

(Configuration of radiation shielding wall)
On the upper surface of the bottom impermeable layer 10, as shown in FIGS. 1, 2, and 6, for example, the quantity (volume) of the bag body 2 carried into the disposal site in a unit period of one day is one step. The radiation shielding wall body 20 is constructed so as to secure the accommodating space 3 having a flat area that can be stored side by side. In the present embodiment, the radiation shielding wall 20 that divides the accommodation space 3 is filled with earth and sand 25 in a box-like wall 21 made of an assembling-type steel net 22 and filled with a predetermined size. A rectangular parallelepiped wall unit is manufactured on-site, and a plurality of wall units are connected in the longitudinal direction. The assembled box-shaped wall 21 is a pre-made product (for example, trade name “Max Sheathley” (manufactured by Taiyo Kogyo Co., Ltd.)) with a lattice-shaped steel net 22 having a predetermined mesh and a non-woven fabric 24 having a box shape along its inner surface. )) Is preferred. As shown in FIG. 4A, the box-shaped wall body 21 initially has a structure in which a net 22a constituting two side walls is connected and a plurality of places are connected by a net 22b. Is assembled by folding a non-woven fabric 24 in a box shape after assembly. The nonwoven fabric 24 prevents the filled earth and sand 25 from spilling from the mesh of the net 22. In this embodiment, each wall unit is filled with earth and sand 25, and as shown in FIG. 4B, four cubic sections each having a side L of about 1 m are connected in the horizontal direction. It consists of a horizontally long rectangular parallelepiped shape. The wall units can be easily connected in the series direction and the parallel direction via a connecting portion 26 provided at the end of the steel net. In this embodiment, as shown in FIG. 6, as a minimum unit, it is installed so as to secure a plane area enough to arrange a predetermined number of bags carried in one day in the vertical and horizontal directions. As shown in FIGS. 1 and 2, the entire housing space 3 is formed so as to cover the outer surface of the bag body stacked in four steps when the box-like wall body 21 is viewed from the cross-sectional direction. The radiation shielding wall body 20 is constructed by being arranged and stacked so as to extend in the longitudinal direction in the side surface and the partition portion in the accommodation space. In addition, sufficient radiation shielding effect can be obtained with a sediment thickness of 1 m for the cubic section of the wall unit with respect to the radioactive substance-containing material.

  The radiation shielding wall body 20 described above is an example of an assembling-type box-shaped wall body 21, but various bag-like foldable containers that form a sac-like body can be used as the radiation shielding wall body 20. For example, a flexible container bag can be used as a sac-like container to fill a flexible container bag with earth and sand to produce a large sandbag, and the large sandbag can be appropriately arranged and laminated to function as a predetermined radiation shielding wall. it can. In addition, a flexible liquid-tight bag that can be used in water tanks, etc., and a plastic or rubber tube that extends in the longitudinal direction is filled with a liquid such as water to produce a sac-like body with a predetermined shape. The sac-like bodies can be arranged to form a radiation shielding wall. In this case, water is generally used as the content liquid to be filled in the bag, etc., but various kinds of liquids are possible as long as they are non-toxic and non-volatile and do not contaminate the surroundings even if the bag or tube breaks due to damage. The liquid can be used.

(Bag body for storing radioactive material-containing materials)
For example, incineration ash of various wastes as radioactive material-containing materials is required to be packed with water-resistant materials. In addition to these conditions, it is required to be easily transported and to ensure stability and the like during lamination. Therefore, the ready-made flexible container bag 2 is used in the present invention. Fig.5 (a) is a schematic perspective view of the flexible container bag 2 used in the Example. The main body sheet of the flexible container bag 2 is made of a highly durable and water-resistant polyethylene sheet. Moreover, you may provide a protective mat inside. The inner protective mat is in contact with the removed soil and plays a role in preventing the main body sheet from being damaged by gravel contained in the removed soil, foreign matter having an acute angle portion, or the like. The main body sheet is made of a base material made of a textile fabric coated with a polyethylene (PE) resin, which is a synthetic resin, in consideration of the treatment after use. It may be made of other synthetic resins such as ethylene-vinyl acetate copolymer (EVA), polypropylene (PP), vinyl chloride (PVC), or synthetic rubber such as chloroprene rubber (CR), and stored radioactively Depending on the type of the substance-containing material, a sheet made of only the synthetic resin or synthetic rubber may be used.

  In this example, as shown in FIG. 5A, a flexible container bag 2 having a diameter of 1200 mm and a height of 1060 mm, which is substantially cylindrical in a state where the contents are filled, was used. The opening at the top of the bag can be closed with various shapes such as a purse-like shape and a lid. As another shape, as shown in FIG. 5B, a type having a substantially rectangular parallelepiped shape in a state where the contents are filled may be used.

  The bag 2 filled with the radioactive substance-containing material is finally partitioned by a radiation shielding wall every day as shown in FIGS. 1 and 2, and each containing space 3 is a covering described later. 30, and is arranged in the plane direction, and further stacked on the upper stage to constitute the entire storage structure. Each bag 2 is stacked closely on the covering on the upper surface of each layer so that the stacked state does not collapse. In the present embodiment, the stacking height is four steps, but it is preferable to appropriately set the number of stacking steps according to the weight of the bag body 2, the ground condition, etc., and to construct the radiation shielding wall body 20 corresponding to the height.

(Structure of the cover)
For example, as shown in FIG. 6, the covering 30 covers a range in which the bags 2 carried in a day are arranged in the accommodation space 3 and covers the top surface of the bags 2 stacked up to the top. At the same time, the radiation shielding wall 20 serves to isolate the accommodation space 3 from the external space 4. FIG. 3B is a partially enlarged view showing an enlarged portion arranged in the accommodation space 3 in a one day storage operation (a portion surrounded by a circle in FIG. 2: III (b)). As shown in the figure, a steel plate 31 is laid to make the upper surface of the arranged bag bodies 2 flat. It is preferable to use a steel plate 31 having a thickness of about 5 mm to 20 mm. In this embodiment, the steel plate 31 having a thickness of 12 mm is partitioned by the radiation shielding wall 20 and arranged in a storage operation for one day. It was laid down on the upper surface of the body 2. Further, a PET woven fabric is laid on the upper surface of the steel plate 31 as the soil covering separation sheet 32, and the stability of the soil covering layer 33 laminated on the upper portion thereof is aimed at. The soil covering thickness was about 15 cm. Covering soil thickness of 15cm, radiation shielding effect is expected to be about 86%.

  Each covering soil layer 33 serving as an intermediate layer in the height direction of the stacked bag body 20 is finished to form a horizontal layer so that the bag bodies 2 can be stably arranged in the upper stage. In the soil covering layer 33 laid on the uppermost surface (portion surrounded by ○ in FIG. 2: III (c)), a predetermined rain gradient is provided from the center position toward both ends, and the rainwater flows down by the cover sheet 40 described later. It is preferable to promote. As shown in FIG. 2, the end portion of the covering body 30 is provided so as to completely cover the upper portion of the box-shaped wall body 21, and is further provided outside the radiation shielding wall body 20 in which the box-shaped wall bodies 21 are laminated. A slope slope covering 34 is formed. The covering 30 has a layer thickness (15 cm) similar to that of the covering layer 33 provided as an intermediate layer in this case as well, in which the housing space 3 and the external space 4 of the bag 2 are separated.

(Other configurations of covering)
In addition to covering soil, it is also preferable to apply a steel plate 31, a protective mat 42, a cover sheet 40, and a radiation shielding sheet 45 as the covering 30 (see FIGS. 2 and 8). Moreover, the covering 30 can be formed by laminating those selected from these. When the cover sheet 40 is used as the covering 30, a sheet formed by coating the synthetic resin on a base material made of synthetic resin such as HDPE or PVC for the purpose of light shielding and water shielding described above, or a fiber fabric. But you can. Further, as a radiation shielding sheet 45 or a radiation adsorbing sheet, a sheet capable of adsorbing radioactive cesium provided with a layer containing a resin or rubber containing a radiation adsorbing material such as zeolite powder, a powder of lead, tungsten, barium sulfate, etc. It is also preferable to employ a sheet capable of shielding radioactive cesium provided with a layer containing a radiation shielding substance in resin or rubber.

(External water shut-off (cover sheet))
In the embodiment shown in FIGS. 1 and 2, a water shielding sheet 41 that becomes a cover sheet 40 is formed as a part of the covering body 30 in order to block the influence of rainwater and the like on the covering soil layers 33 and 34 as the covering body 30. Laid. Since the water shielding sheet 41 also requires water shielding at the joint, a light shielding layer integrated HDPE sheet (thickness 1.5 mm) that can be joined by welding and has high durability was used. As shown in FIG. 2, the cover sheet 40 covers a soil covering layer (upper surface covering soil 33, slope covering soil 34) and a protective mat 42, and an end portion is fixed on the ground by a concrete block 43 or the like. As the protective mat 42, the same thing as the protective mat 12 can be used.

(Outside water blocking (membrane structure roof))
FIG. 8 shows an embodiment in which a membrane surface roof (tent roof) 50 in which a membrane material 52 is stretched on a frame 51 having a frame structure is adopted as a membrane surface roof instead of the cover sheet 40 described above. Since rainwater and the like are completely blocked by the tent roof 50, the upper surface of the housing space 3 in which the bag body 2 is stacked, and the entire surface of the box-shaped wall body 21 as the radiation shielding wall body 20 stacked on the side surface, It is covered with a radiation shielding sheet 45 for the purpose of fail-safe. The other configuration is the same as that of the storage structure 1 shown in FIGS.

[About bag storage work in storage structure]
In the storage structure for radioactive substance-containing material constructed according to the present invention, for example, the final disposal site is accommodated according to the number of bags filled with the radioactive substance-containing material carried in between, for example, one day as a unit period. The space was partitioned and the upper surface was covered. The bag storage operation will be described with reference to FIGS. 6, 7, and 9.

  FIG. 7 is a work state diagram showing bag storage, laminating work, and final laminated shape in the radioactive substance-containing material storage structure. The figure shows a state in which the radiation shielding walls and the bags arranged on the bottom impermeable layer are arranged as shown in FIG. That is, prior to the bag storage operation, first, the radiation shielding wall 20 corresponding to the outer wall surface is constructed using the box-shaped wall 21. Then, along the radiation shielding wall 20, the bag 2 filled with the radioactive material-containing material for the daily storage quantity is vertically and horizontally within a range in which two or three sides are partitioned by the radiation shielding wall 20. Keep them side by side. Then, after the bags 2 of the quantity for one day are arranged in a substantially rectangular shape in plan view, the remaining sides are closed with the radiation shielding wall body 20. Further, a steel plate 31 is laid so as to cover the entire upper surface of the arranged bags, and a covering soil layer 33 as a covering 30 is laid thereon with a thickness of 15 cm. Immediately after the bags 2 are arranged on the entire plane of the compartment in the accommodation space, the soil is immediately covered. The covering layer 33 covered on the same day is constructed so as to be flat so as to be an intermediate layer in the stacking direction. When the bags are arranged on the entire plane of the first stage, the same bag body 2 is stored in the second stage of the upper layer sandwiching the covering layer 33. FIG. 7B is an explanatory diagram showing the storage state of the bag body 2 in the third stage. As shown in the figure, since the radiation shielding wall body 20 is disposed on all the surfaces corresponding to the outer walls of the partition portion in the accommodating space, the radiation shielding effect in the side surface direction is ensured. Moreover, the radiation shielding effect to the upper side is also ensured by the soil covering layer 33 formed in the upper surface of the bag body 2 in each step.

  FIG. 9 shows an embodiment in which a light shielding layer integrated water shielding sheet 41 and a membrane surface structure roof 50 are used in combination. The membrane surface roof 50 used in this embodiment is provided with detachable traveling wheels (not shown) at the lower end of each frame 51, and the entire frame 51 can move in the direction of the arrow. At this time, a membrane surface (tent roof) is provided with a slack between the frames 51 so that the adjacent frames 51 are completely unfolded when they are separated as much as possible. Therefore, the membrane structure roof is stretched by positioning the frame 51 so as to cover the range in which the bag 2 is stored and the range in progress. The membrane structure roof 50 finally covers the entire accommodation space in accordance with the progress of the bag storage operation, thereby improving the efficiency of storage of the bag 2 and ensuring the safety during storage. be able to.

[Another embodiment of radiation shielding wall]
FIG. 10A is performed in a space surrounded by the concrete L-shaped retaining wall 28 provided with a precast concrete L-shaped retaining wall 28 as a fail-safe wall body as the radiation shielding wall body 20. The storage structure completed by the storage operation is shown. Also in this embodiment, the radiation shielding wall body is constructed at the outer position using the box-shaped wall body 21, and the storage operation of the bag body 2 is performed in the same manner as described above, for example, with one day as a unit period. The box-shaped wall 21 is arranged around the bag body 2 that has been stored. Furthermore, the upper surface of the bag body 2 arranged and stored in a predetermined range as the same day covering soil is covered with a steel plate 31 and a covering soil layer 33 as the covering body 30. By the way, in the accommodation space 3 in which the bag bodies 2 are arranged, as shown in the figure, the thickness of the bottom plate 28b of the retaining wall is reduced. A thickness corresponding to the bottom plate thickness of the L-shaped retaining wall 28 as a raised structure for adjusting the height and for avoiding contact between the bag 2 and water as much as possible when the upper surface of the water-impervious sheet 11 is submerged. The pallet 6 is laid, and the material of the pallet 6 can be made of synthetic resin or wooden. A U-shaped groove 7 is provided inside the bottom plate 28b. A water shielding sheet 11 is laid on the lower surface of the pallet 6 in the same manner as the storage structure 1 described above, and the end of the water shielding sheet 11 is bent up by a holding member 8 located on the U-shaped groove 7 as shown in the figure. The L-shaped retaining wall 28 is fixed to the tip fixing portion 60a of the fixing bracket 60 attached to the inner surface of the wall body 28a.

  In this configuration, a cover sheet 40 that covers the upper surface of the bag body 2 is provided as the covering body 30 after the bag body 2 is stacked at a predetermined height in order to prevent intrusion of external water. As shown in the figure, the edge 40a of the cover sheet 40 is on the inner surface of the wall 28a of the L-shaped retaining wall 28, so that a predetermined tension is applied to the cover sheet 40 on the intermediate fixing portion 60b positioned outward from the tip fixing portion 60a. And is fixed with a gap between the wall 28a and the wall 28a. A plate-shaped drainage material 15 is laid on the upper surface of the bottom slab 28 b of the L-shaped retaining wall 28. In addition, it is preferable to position the position of the front end fixing portion 60a above the position of the intermediate fixing portion 60b. With such a structure, the effect of preventing the intrusion of external water can be enhanced.

  Since the external water intrusion prevention structure has the above-described configuration, for example, when rainwater or the like flows down the surface of the cover sheet 40, the rainwater flows between the intermediate fixing portion 60b and the wall body 28a and flows into the bottom plate 28b. The water is drained into the U-shaped groove 7 below the water shielding sheet 11 through the drainage material 15.

  The fixing bracket 60 having the intermediate fixing portion 60b for fixing the end portion of the cover sheet 40 is installed by a single pipe or the like using a hole (not shown) provided in the L-shaped retaining wall 28, and the hole May use the drain hole of the L-shaped retaining wall 28. The sheet end side 40a is preferably connected to the intermediate fixing portion 60b by rope binding or the like.

(Modification of radiation shielding wall)
A concrete wall such as a precast concrete L-type retaining wall has a wall thickness of 15 cm and a radiation shielding effect of about 90% can be secured. Furthermore, in order to enhance the shielding effect of the radiation shielding wall body as the wall for fail-safe of FIG. 10A and to improve the stability of the wall body, the box-shaped wall body disposed on the outer periphery of the bag body 2 It is also preferable to use a box-like wall body 21 similar to 21 in combination. FIG. 10B shows an embodiment in which a three-stage box-like wall body 21 is laminated on the bottom slab 28 b of the L-shaped retaining wall 28. In this case, the fixing bracket 60 is preferably fixed to the support rod 61 that penetrates the lowermost box-shaped wall body 21 and protrudes from the inner surface of the box-shaped wall body 21. The end sides of the cover sheet 40 and the water shielding sheet 11 may be fixed to the intermediate fixing portion 60b as in the case of FIG. Moreover, in order to pile up the box-shaped wall body 21 stably, it is preferable to connect a concrete wall body and each box-shaped wall body 21 with the support rod 61, respectively.

  The present invention is not limited to the above-described embodiments, and various modifications within the scope of the claims are possible. In other words, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Storage structure 2 Bag body 2W Large sandbag 3 Accommodating space 4 External space 10 Bottom surface water shielding layers 11, 41 Water shielding sheets 12, 42 Protective mat 13 Covering layer 20 Radiation shielding wall body 21 Box-shaped wall body 25 Earth and sand 30 Covering body 31 Steel plate 33 Covering layer 40 Cover sheet 50 Tent roof (membrane structure roof)

Claims (7)

A bottom impermeable layer is laid on the entire bottom surface of the space for storing the radioactive substance-containing material, a folded net is developed on the bottom impermeable layer, and an assembly is filled with earth and sand to form a box-shaped wall body, A radiation shielding wall that is self-supported by connecting the box-shaped walls in a row, and encloses a part of the side of the space that can be filled by a storage operation for a unit period to form an accommodation space. houses arranged a plurality of bag body filled with the radioactive material contained material into the housing space, after storage work unit period, while covering the upper surface of the stowed bag, the radiation shield and the remaining side closed with a wall separates the said housing space and an external space where the bag body is stored in each storage work unit period, further perform storage operations of the bag in the upper layer of the receiving space of the bag, After completing the stacking up to the predetermined number of steps, A serial radiation shield wall is covered with the outermost layer of the jacket, method for constructing a storage structure of the radioactive substance-containing material, characterized by constructing the storage structure of the radioactive substance-containing material. The method for constructing a storage structure for a radioactive substance-containing material according to claim 1, wherein the bottom water-impervious layer comprises a water-impervious sheet as a base layer, and a soil cover layer is laminated on the base layer . The box-like wall body is folded and attached along the inner surface of the mesh body in a folded state, and the nonwoven fabric is stretched along the inner surface of the mesh body in an unfolded and assembled state. The method for constructing a storage structure for a radioactive substance-containing material according to claim 1, which is in a state .   The method for constructing a storage structure for a radioactive substance-containing material according to claim 1, wherein the radiation shielding wall body is a combination of the box-shaped wall body and a precast concrete wall body.   The method for constructing a storage structure for a radioactive substance-containing material according to claim 1, wherein the covering is formed by laying a steel plate on the upper surface of the bag body and laminating a cover layer on the steel plate.   The radioactive substance-containing material storage structure construction method according to claim 1, wherein the outermost layer covering is a water shielding sheet that covers an uppermost surface of the laminated bag and the radiation shielding wall.   2. The radioactive substance-containing material storage structure according to claim 1, wherein the outermost layer covering is a membrane-structured roof that covers the uppermost surface of the laminated bag and the radiation shielding wall with an upper space thereof. Construction method.

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