JP6500333B2 - Artificial barrier structure and overpack recovery method - Google Patents

Description

  The present invention relates mainly to an artificial barrier structure and an overpack recovery method of a radioactive waste disposal site where high-level radioactive waste is disposed in the deep geological formation.

  The high-level radioactive waste generated by reprocessing spent fuel from nuclear power plants is several hundred meters below ground, which is a natural barrier confined to an artificial barrier consisting of a vitrified body, an overpack and a buffer material. It is planned to dispose underground in the bedrock.

  In the case of deep underground disposal, the half life of the target radioactive substance may be extremely long, and management over 10,000 years is required, but new processing technology is established after disposal, or the disposal site is changed If this is the case, proposals have been made to make it possible to recover high-level radioactive waste.

  On the other hand, in the past, recovery of high level radioactive waste during the disposal period has not been assumed, so new technological development for recovery has become necessary.

  The high level radioactive waste is buried in the buffer in the state of being enclosed in the overpack as described above, and it is necessary to take out the overpack from the buffer to recover the high level radioactive waste. As a buffer material, bentonite is selected which exhibits water-repellant properties by swelling by itself even if there is intrusion of groundwater.

  In response to this, a method of collapsing and removing the bentonite without swelling the bentonite by salt water has been proposed (Patent Document 1, Non-Patent Document 1).

JP, 2010-008375, A

"Sampling material removal technology using saltwater for waste recovery," 65th Annual Conference of the Japan Society of Civil Engineers (September 2010) "Examination on bentonite barrier removal by ice blast method," Proceedings of the Annual Meeting of the Japan Atomic Energy Society Spring (March 2008)

  However, in the above-mentioned method of collapsing bentonite using salt water, it is necessary to separately process a large amount of bentonite slurry generated at that time, and above all, a radioactive waste called bentonite slurry is generated.

  Moreover, in order to solve this, the method of crushing and removing this bentonite is also proposed by spraying dry ice as a blast material on bentonite (nonpatent literature 2).

  However, since the buffer material in which the overpack is embedded has a size of 2 m or more in outer diameter and 3 m or more in height, there is a concern that the grinding and removal may take a long time.

  That is, the above-mentioned crushing removal is limited only to the vicinity of the top of the overpack being exposed, and even if it is attempted to pull up the overpack using the exposed portion, the rest except the vicinity of the top remains embedded in bentonite. There is a concern that large shear adhesion from bentonite acts on the circumferential surface with pulling up, and an unexpected failure may occur in the overpack.

  As a result, a large portion of bentonite surrounding the overpack has to be crushed and removed, causing a problem that the grinding and removal operation must be performed for a long time.

  The present invention has been made in consideration of the above-mentioned circumstances, and an artificial barrier structure and an overpack capable of safely and quickly removing the overpack from the buffer without generating new radioactive waste. The purpose is to provide a recovery method for

In order to achieve the above object, the artificial barrier structure according to the present invention comprises, as described in claim 1, an overpack in which radioactive waste is enclosed, a container body and a lid attached to the opening of the container body. In addition to being housed in a collection container, the collection container is embedded in a buffer material such that the lid is on the upper side, and a fixing portion fixed to the buffer material is protruded on the upper surface of the lid .

Further, according to the overpack recovery method of the present invention, as described in claim 2, an overpack in which radioactive waste is enclosed is collected into a recovery container comprising a container body and a lid attached to the opening of the container body. A method of recovering the overpack from an artificial barrier structure in which the recovery container is embedded in a shock absorbing material with the cover facing upward, and the surface of the shock absorbing material and the peripheral upper surface of the cover are accommodated. By forming an annular cutting groove extending substantially vertically between them, the shock absorbing material is divided into a shock absorbing material spreading immediately above the recovery container and a shock absorbing material spreading around the same in the height range of the cutting groove And
The buffer material spreading right above the collection container is pulled up and removed as a block, and the lid of the collection container is removed in a form attached to the block, or the buffer material spreading directly above the collection container is pulled up removed After removing the lid of the collection container,
Removing the overpack from the collection container;

In the overpack recovery method according to the present invention, as described in claim 3, the cover is fixed to the block by projecting the fixing portion fixed to the buffer material on the upper surface of the cover. It is removed in the form of adhesion .

  In the artificial barrier structure according to the present invention, as described in claim 4, the overpack in which the radioactive waste is enclosed is accommodated in a recovery container consisting of only a container main body having an opening, and the recovery container is It embeds in a shock absorbing material so that the said opening may become upper direction, and the edge which can interrupt | pull a tensile load transmission intervenes between the upper surface of the said overpack, and the said shock absorbing material.

  In the artificial barrier structure according to the present invention, the edge cutting body is made of sand.

The overpack recovery method according to the present invention is, as described in claim 6, a method for recovering the overpack from the artificial barrier structure according to the fourth or fifth aspect of the present invention. By forming an annular cutting groove extending in a substantially vertical direction between the surface and the upper edge of the collection container, the buffer material is expanded immediately above the collection container in the height range of the cutting groove and its cushioning material Divided into a buffer material that spreads around,
The edge cutting body and removing the cushioning material extends immediately above the collection container after pulling removed as a block,
Removing the overpack from the collection container;

[First Invention (Reference Invention) ]
In the artificial barrier structure according to the first aspect of the present invention, the overpack is similar to the case where it is directly buried in the buffer material in that the periphery is surrounded by the buffer material, and water from the rock reaches the overpack. In the same way as in the past, the effect of preventing the diffusion of the radioactive substance or the water containing the radioactive substance is prevented.

  In addition, in the first invention, the overpack is accommodated in a collection container comprising a container main body and a lid attached to the opening of the container main body, and the collection container is cushioned so that the lid is on top. Since it is buried, the buffer material spreading right above the collection container is removed, and the lid of the collection container exposed thereby is removed, so that the shear adhesion from the buffer material does not act on the overpack and the collection container It is possible to recover the overpack only by removing the buffer material within a limited range of immediately above, and thus the overpack can be recovered safely and in a short time.

  It is optional how and when the lid of the recovery container is removed, and the buffer material spreading right above the recovery container may be removed and then removed appropriately, or the buffer material spreading directly above the recovery container may be blocked When the lid of the recovery container is attached to the shock absorbing material, the lid may be removed together with the shock absorbing material in the case of pulling it up and removing it. If the fixing portion is protruded from the upper surface of the lid, the lid can be reliably pulled up together with the shock absorbing material when the shock absorbing material expanding immediately above the collection container is pulled up and removed as a block.

[Second Invention]
When recovering the overpack from the artificial barrier structure according to the first aspect of the present invention, how to remove the buffer material spreading right above the recovery container is optional, for example, using dry ice as a blast material as a blast material. By spraying, it is possible to crush and remove the shock absorbing material spreading right above the recovery container, but in the second invention, the shock absorbing material mentioned above extends substantially in the vertical direction between the surface and the peripheral upper surface of the lid. The buffer material is divided into a buffer material spreading immediately above the collection container and a buffer material spreading around the same in the height range of the cutting groove by forming an annular cutting groove extending to the top of the collection container. or with pulling removing buffer material extending as a block removing the lid of the collection container in the form of adhered to the block, or the block buffer material extending directly above the collection container Remove the lid of the collection container after pulling removed Te, thereafter, taken out overpack from the container body.

  In this way, it is possible to remove the buffer material spreading immediately above the collection container as a block by cutting only a small area for forming the cutting groove, and thus the overpack can be collected in a shorter time. It becomes.

[Third Invention]
Also in the artificial barrier structure according to the third invention, as in the first invention, the overpack is the same as the case where it is directly embedded in the shock absorbing material in that the periphery is surrounded by the shock absorbing material, and The action of the shock absorbing material is surely exerted as in the prior art.

  In addition, in the third invention, the overpack is accommodated in a collection container consisting only of a container body having an opening formed therein, the collection container is embedded in the buffer material such that the opening is on the upper side, and There is an edge between the upper surface of the pack and the shock absorbing material, which can interrupt the tensile load transfer. Therefore, when pulling up the shock absorbing material that spreads just above the collection container as a block, the upper surface of the overpack has a tensile force. It does not work, and by removing the exposed rim by it, it does not affect the shear adhesion from the shock absorbing material on the overpack and only removes the shock absorbing material within a limited range immediately above the recovery container. The overpack can be recovered at a later stage, and thus the overpack can be recovered safely and in a short time.

  Although it is optional how to configure the rim, for example, the case of sand is a typical example.

[The fourth invention]
In the fourth invention, in recovering the overpack from the artificial barrier structure according to the third invention, an annular cutting groove extending in a substantially vertical direction between the surface of the cushioning material and the upper edge of the recovery container described above. The shock absorbing material is divided into a shock absorbing material that spreads immediately above the collection container and a shock absorbing material that spreads around it in the height range of the cutting groove, and then a shock absorbing material that spreads directly above the collection container is used as a block. After pulling up and removing , the rim is removed and then the overpack is removed from the collection container.

  In this way, combined with the above-described action of the edge cutting body, it is possible to remove the buffer material spreading directly above the recovery container as a block by cutting only a small range for forming the cutting groove, and thus It is possible to recover the overpack in a shorter time.

[Common to each invention]
The collection container in each invention mentioned above can be comprised, for example with carbon steel or tempered glass.

The perpendicular sectional view of artificial barrier structure 31 concerning a 1st embodiment. The schematic block diagram of the air blast cutting device 1 used when removing the buffer material 24 which spreads just on collection | recovery container 33. FIG. Explanatory drawing which showed a mode that the overpack 32 embed | buried under the shock absorbing material 22 was collect | recovered using the air blast cutting device 1. FIG. Explanatory drawing which showed a mode that the overpack 32 was collect | recovered continuously. Explanatory drawing which showed a mode that the overpack 32 was collect | recovered in the artificial barrier structure which concerns on a modification. The perpendicular sectional view of the artificial barrier structure 61 concerning a 2nd embodiment. Explanatory drawing which showed a mode that the overpack 32 embed | buried under the shock absorbing material 22 was collect | recovered using the air blast cutting device 1. FIG. Explanatory drawing which showed a mode that the overpack 32 was collect | recovered continuously.

  Hereinafter, embodiments of the artificial barrier structure and the overpack recovery method according to the present invention will be described with reference to the attached drawings.

First Embodiment
FIG. 1 is a vertical sectional view showing an artificial barrier structure according to the present embodiment. In the artificial barrier structure 31 according to this embodiment, a disposal tunnel having a diameter of about 5 m is constructed in a bedrock several hundred meters underground which is a natural barrier, and a disposal hole having a diameter of about 2 m is formed vertically downward from the disposal tunnel. The internal space of the disposal hole, and as shown in the figure, the overpack 32 is accommodated in the recovery container 33, and the recovery container is embedded in the buffer material 22 made of bentonite. Yes.

  The overpack 32 is made by solidifying high-level radioactive waste with glass and then enclosing it in a cylindrical steel container made of carbon steel or the like.

  The recovery container 33 is configured of a bottomed cylindrical container body 34 and a disc-like lid 36 attached to the opening 35 of the container body, and the buffer material 22 is placed so that the lid 36 is on the upper side. Buried in

  The recovery container 33 can be made of, for example, carbon steel or tempered glass.

  In the artificial barrier structure 31 constructed in this manner, the overpack 32 is similar to the case where it is directly buried in the buffer material 22 in that the buffer material 22 surrounds the periphery, and the water from the rock is over The function of preventing the pack 32 from being reached or preventing the water containing the radioactive substance from diffusing from the overpack 32 to the rock is exerted as in the conventional manner.

  In addition, the overpack 32 is accommodated in a collection container 33 consisting of a container body 34 and a lid 36 attached to the opening 35 of the container body, and the collection container is buffered so that the lid 36 is on top. Since the lid 36 is exposed by removing only the buffer material which is embedded in the material 22 and spreads immediately above the recovery container 33 among the buffer materials 22, the lid 36 is removed and the overpack 32 is removed from the container body 34. You can take out the

  FIG. 2 is a schematic configuration view showing the air blast cutting device 1 used when removing the buffer material spreading right above the collection container 33. As shown in FIG.

  As shown in the figure, the air blast cutting device 1 has an injection mechanism 3 for injecting dry ice with compressed air through the injection nozzle 2 and a material axis of the injection nozzle parallel to the injection direction of the injection nozzle 2 And a driving mechanism 4 for holding the injection nozzle so that the injection nozzle 2 can turn around the axis 9 extending to a position away from and can move back and forth in the injection direction.

  The injection mechanism 3 includes a dry ice supply machine 5 for producing and supplying dry ice and a compressor 6 for supplying compressed air, and connects the dry ice supply machine 5 to the injection nozzle 2 via a dry ice supply hose 7 At the same time, by connecting the compressor 6 to the injection nozzle 2 via the compressed air supply hose 8, dry ice can be injected together with the compressed air from the injection nozzle.

  The driving mechanism 4 is attached to a rotating shaft 10 disposed along the axis 9, a motor 11 connected to one end of the rotating shaft, a pivoting arm 12 coupled to the other end, and a tip of the pivoting arm The feed mechanism 13 is generally configured.

  Here, the injection nozzle 2 is attached to the end of a rod 14 formed of a hollow tube, and the feed mechanism 13 is adapted to hold the rod 14 back and forth freely, and the dry ice supply hose 7 and The compressed air supply hose 8 is connected to the injection nozzle 2 in a state of being inserted into the inner space of the rod 14.

  The feed mechanism 13 has, for example, a rack gear (not shown) attached to the circumferential surface of the rod 14 along the material axis direction, and a motor (not shown) having a pinion gear engaged with the rack gear attached to the rotation shaft Can be built in.

  The length of the rod 14 may be appropriately set according to the cutting depth of the shock absorbing material 22 by injection of dry ice and compressed air, that is, the depth of the cutting groove described later.

  In order to remove the buffer material spreading right above the collection container 33 using the air blast cutting device 1, first, as shown in FIG. 3, the drive mechanism 4 is set so that the axis 9 is substantially perpendicular to the surface of the buffer material 22. By appropriately operating the feed mechanism 13 to advance or retract the rod 14 so that the rod 14 is held by the feed mechanism 13 near its lower end.

  Next, while the injection nozzle 2 is rotated about the axis 9 by operating the motor 11, the dry ice feeder 5 and the compressor 6 are operated to inject dry ice together with compressed air from the injection nozzle 2.

  In this way, the dry ice and compressed air jetted from the jet nozzle 2 cut the surface of the cushioning material 22 along a circle centered on the axis 9, and the cushioning material 22 has an annular cutting groove 23 Since it is formed, the feed mechanism 13 is further operated to advance the rod 14 and thus the injection nozzle 2 attached to the tip thereof, thereby digging the bottom of the cutting groove 23.

  When operating the motor 11 and the feed mechanism 13, the motor 11 is operated so that, for example, the swing arm 12 is inverted every 360 ° so that the bottom surface of the cutting groove 23 is dug down along the circumferential direction. It suffices to operate the feed mechanism 13 so that the rod 14 advances when it is reversed.

  The length of the swing arm 12 is appropriately set such that the diameter of the cutting groove 23 is substantially the same as the diameter of the lid 36.

  When the bottom surface of the cutting groove 23 reaches the peripheral upper surface of the lid 36, the cutting of the shock absorbing material 22 is ended.

  Thus, when the bottom of the cutting groove 23 is dug down in the vertical direction, the cushioning material 22 is a cylindrical inner region located inside the annular cutting groove 23 in the height range of the cutting groove, that is, directly above the recovery container 33. 4 and the buffer material 25 which spreads out to the region located outside the buffer material 24, the buffer material 24 which spreads immediately above the collection container 33 is then covered with the lid of the collection container 33, as shown in FIG. Pull up as a block with 36.

  Next, the overpack 32 is taken out of the container body 34 and collected.

  As described above, according to the artificial barrier structure 31 according to the present embodiment, the overpack 32 is accommodated in the collection container 33 including the container main body 34 and the lid 36 attached to the opening 35 of the container main body Since the recovery container is embedded in the buffer material 22 so that the lid 36 is on the upper side, the buffer material 24 spreading right above the recovery container 33 is removed, thereby removing the lid 36 of the recovery container 33 exposed. As a result, it is possible to recover the overpack 32 only by removing the shock absorbing material 24 within a limited range of immediately above the recovery container 33 without causing the shear adhesion from the shock absorbing material 22 to act on the overpack 32. Thus, the overpack 32 can be recovered safely and in a short time.

  Further, according to the overpack recovery method according to the present embodiment, by forming the annular cutting groove 23 in the shock absorbing material 22, the shock absorbing material is expanded immediately above the recovery container 33 in the height range of the cutting groove 23. Since the shock absorbing material 24 is divided into the shock absorbing material 24 and the shock absorbing material 25 on the outside thereof and then pulled up with the lid 36 of the recovery container 33 as a block, then the overpack 32 is taken out from the container body 34. By cutting only a slight range for forming the cutting groove 23, it is possible to remove the shock absorbing material 24 spreading immediately above the collection container 33 as a block, thus making it possible to collect the overpack 32 in a shorter time. .

  In the present embodiment, the annular cutting groove 23 is formed in the buffer material 22 using the air blast cutting device 1, but instead of this, a known cutting device may be appropriately used.

  Further, in the present embodiment, the annular cutting groove 23 is formed in the cushioning material 22 so that the cushioning material 24 expanding immediately above the collection container 33 is removed as a block, but instead of this, the collection container 33 is removed. The buffer material spreading immediately above may be crushed and removed by spraying using dry ice or other particles as a blast material, or by any other known method.

  In such a configuration, work is time-consuming because it can not be removed as a block, but the function and effect of the artificial barrier structure 31 such that it is sufficient to remove only the buffer material spreading right above the recovery container 33 is different from the above embodiment. There is no.

  Further, in the present embodiment, on the premise that the cover 36 of the recovery container 33 adheres to the lower surface of the buffer material 24 due to the viscosity of the buffer material 22, the buffer material is pulled up together with the cover 36 of the recovery container 33. However, when pulling up the buffer material 24 as a block, if the lid 36 of the recovery container 33 remains in the container body 34 without adhering to the buffer material, the lid 36 may be removed separately from the container body 34.

  Further, although not particularly mentioned in the present embodiment, as shown in FIG. 5, it is possible to adopt a configuration in which the fixing portion 51 fixed to the buffer material 24 is protruded on the upper surface of the lid 36.

  The fixing unit 51 can be configured, for example, by curving a strip-like steel plate into a cylindrical shape and joining the both ends thereof.

  According to this configuration, when the shock absorbing material 24 expanding immediately above the recovery container 33 is removed as a block, the lid 36 of the recovery container 33 can be reliably pulled up together with the shock absorbing material.

Second Embodiment
Next, a second embodiment will be described. The same reference numerals are given to parts substantially the same as those of the first embodiment, and the description thereof is omitted.

  FIG. 6 is a vertical sectional view showing the artificial barrier structure according to the present embodiment. In the artificial barrier structure 61 according to this embodiment, as in the case of the artificial barrier structure 31 described in the first embodiment, a disposal tunnel having a diameter of about 5 m is constructed in a few hundred meters underground underground which is a natural barrier. A disposal hole having a diameter of about 2 m is formed vertically downward from the inside, and is installed in the internal space of the disposal hole, and as shown in the figure, the overpack 32 is accommodated in the recovery container 62, The recovery container is embedded in a buffer material 22 made of bentonite.

  The recovery container 62 is constituted only by a bottomed cylindrical container main body in which an opening 64 is formed, and is embedded in the buffer material 22 so that the opening is on the upper side.

  The recovery container 62 can be made of, for example, carbon steel or tempered glass.

  Between the upper surface of the overpack 32 and the cushioning material 22, a sand edger 63 is interposed, so that the tensile load transmission between them is interrupted.

  In the artificial barrier structure 61 constructed in this manner, the overpack 32 is similar to the case where it is directly buried in the cushioning material 22 in that the cushioning material 22 surrounds the periphery, and the water from the rock is over The function of preventing the pack 32 from being reached or preventing the water containing the radioactive substance from diffusing from the overpack 32 to the rock is exerted as in the conventional manner.

  In addition, the overpack 32 is accommodated in the recovery container 62 consisting only of the container body in which the opening 64 is formed, and the recovery container is embedded in the buffer material 22 with the opening 64 facing upward and A rim 63 is interposed between the upper surface of the pack 32 and the shock absorbing material 22. If only the shock absorbing material of the shock absorbing material 22 which spreads just above the recovery container 62 is removed, the rim 63 is exposed thereby. Therefore, it may be removed and the overpack 32 may be removed from the recovery container 62.

  In order to remove the buffer material spreading right above the collection container 62, the air blast cutting device 1 may be used as in the first embodiment.

  That is, first, as shown in FIG. 7, the drive mechanism 4 is positioned so that the axis 9 is substantially perpendicular to the surface of the shock absorbing material 22, and the feed mechanism 13 is appropriately operated to move the rod 14 forward or backward. Positions the rod so that it is held by the feed mechanism 13 near its lower end.

  Next, while the injection nozzle 2 is rotated about the axis 9 by operating the motor 11, the dry ice feeder 5 and the compressor 6 are operated to inject dry ice together with compressed air from the injection nozzle 2.

  In this way, the dry ice and compressed air jetted from the jet nozzle 2 cut the surface of the cushioning material 22 along a circle centered on the axis 9, and the cushioning material 22 has an annular cutting groove 23 Since it is formed, the feed mechanism 13 is further operated to advance the rod 14 and thus the injection nozzle 2 attached to the tip thereof, thereby digging the bottom of the cutting groove 23.

  When operating the motor 11 and the feed mechanism 13, the motor 11 is operated so that, for example, the swing arm 12 is inverted every 360 ° so that the bottom surface of the cutting groove 23 is dug down along the circumferential direction. It suffices to operate the feed mechanism 13 so that the rod 14 advances when it is reversed.

  The length of the swing arm 12 is appropriately set such that the diameter of the cutting groove 23 is substantially the same as the diameter of the recovery container 62.

  When the bottom surface of the cutting groove 23 reaches the upper edge of the recovery container 62, the cutting of the buffer material 22 is finished.

  Thus, when the bottom of the cutting groove 23 is dug down in the vertical direction, the cushioning material 22 is a cylindrical inner region located inside the annular cutting groove 23 in the height range of the cutting groove, that is, directly above the recovery container 62. Since the buffer material 24 is divided into the buffer material 24 which spreads in and the buffer material 25 which spreads in the region located outside of it, next, as shown in FIG.

  Next, after the rim 63 is appropriately removed, the overpack 32 is taken out of the recovery container 62 and recovered.

  As described above, according to the artificial barrier structure 61 according to the present embodiment, the overpack 32 is accommodated in the collection container 62 consisting of only the container body in which the opening 64 is formed, and the collection container has the opening 64 Since the rim 63 is interposed between the upper surface of the overpack 32 and the shock absorbing material 22 while being buried in the shock absorbing material 22 so as to be the upper side, the shock absorbing material 24 spreading right above the recovery container 62 is blocked. When pulling up, there is no tensile force acting on the upper surface of the overpack 32, and the shear adhesion from the buffer material 22 does not act on the overpack 32 by removing the exposed rim 63 thereby, and It is possible to recover the overpack 32 simply by removing the buffer material 24 within a limited range immediately above the recovery container 62. Comb can be recovered overpack 32 safely and in a short time.

  Further, according to the method of recovering the overpack according to the present embodiment, by forming the annular cutting groove 23 in the shock absorbing material 22, the shock absorbing material is expanded immediately above the recovery container 62 in the height range of the cutting groove 23. Since the shock absorbing material 24 is divided into the shock absorbing material 24 and the shock absorbing material 25 outside the shock absorbing material 24 after that, the shock absorbing material 24 is pulled up as a block and the overcutting 32 is taken out from the recovery container 62 after removing the rim 63 properly. By cutting only a small area for forming the groove 23, the buffer material 24 spreading immediately above the collection container 62 can be removed as a block, and thus the overpack 32 can be collected in a shorter time.

  In the present embodiment, the annular cutting groove 23 is formed in the buffer material 22 using the air blast cutting device 1, but instead of this, a known cutting device may be appropriately used.

  Further, in the present embodiment, the edge of the present invention is constituted by the edge 63 made of sand, but the edge of the present invention can block the tensile load transmission between the upper surface of the overpack and the shock absorbing material. As long as it is a material, what kind of material it comprises is arbitrary.

22 shock absorbing material 23 cutting groove 31, 61 artificial barrier structure 32 overpack 33, 62 collection container 34 container main body 35, 64 opening 36 lid 24 cushioning material which spreads just above the collection container 25 buffer material 51 which spreads around the periphery 51 fixing portion 63 Border

Claims (6)

An overpack in which radioactive waste is enclosed is accommodated in a recovery container consisting of a container body and a lid attached to the opening of the container body, and the recovery container is embedded in a buffer material with the lid facing upward. An artificial barrier structure characterized in that a fixing portion fixed to the buffer material is protruded from the upper surface of the lid. An overpack in which radioactive waste is enclosed is accommodated in a recovery container consisting of a container body and a lid attached to the opening of the container body, and the recovery container is embedded in a buffer material with the lid facing upward. Method of recovering the overpack from the artificial barrier structure, wherein the buffer material is formed by forming an annular cutting groove extending substantially vertically between the surface thereof and the upper peripheral surface of the lid. The material is divided into a shock absorbing material which spreads immediately above the collection container in the height range of the cutting groove and a shock absorbing material which spreads around it,
The buffer material spreading right above the collection container is pulled up and removed as a block, and the lid of the collection container is removed in a form attached to the block, or the buffer material spreading directly above the collection container is pulled up removed After removing the lid of the collection container,
Removing the overpack from the collection container. 3. The overpack recovery method according to claim 2, wherein the fixing portion to be fixed to the buffer material is protruded on the upper surface of the lid so that the lid is removed in the form of being attached to the block . An overpack in which radioactive waste is enclosed is accommodated in a recovery container consisting only of a container body having an opening, and the recovery container is embedded in a buffer material such that the opening is on the top, and tensile load transmission is interrupted An artificial barrier structure characterized in that a possible edge is interposed between the upper surface of the overpack and the cushioning material. The artificial barrier structure according to claim 4, wherein the rim is made of sand. 6. A method of recovering the overpack from the artificial barrier structure according to claim 4 or 5, wherein the cushioning material has an annular cutting groove extending substantially vertically between the surface thereof and the upper edge of the recovery container. Forming the shock absorbing material into a shock absorbing material that spreads immediately above the collection container in the height range of the cutting groove and a shock absorbing material that spreads around the same;
The edge cutting body and removing the cushioning material extends immediately above the collection container after pulling removed as a block,
Removing the overpack from the collection container.

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