JP3769721B2 - Waste disposal method and underground disposal facility - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waste underground disposal method and an underground disposal facility that can dispose of low-level radioactive waste or the like in a ground having a relatively low strength while being isolated and disposed underground.
[0002]
[Prior art]
Regarding the disposal of radioactive waste, it is considered to bury it in underground facilities after taking necessary and sufficient safety measures. Since Japan has a wide range of geology from hard rock to soft rock, it is considered to construct a disposal facility for soft rock with relatively low strength.
[0003]
Among low-level radioactive wastes, those with relatively high radionuclide concentrations are being considered for disposal by constructing a large-section cavity in a slightly deep underground (50-100m or deeper) rather than shallow-layer disposal. .
[0004]
In that case, it is expected that it will be very difficult to ensure the stability of the natural ground because a cavity with a large cross section will be constructed for the relatively low strength ground in the deep underground.
[0005]
[Problems to be solved by the invention]
Therefore, in order to dispose of the waste in a place with such conditions, it is necessary to construct a large-scale support work, and there is a risk that the construction cost will rise significantly.
[0006]
In view of the above circumstances, an object of the present invention is to provide an underground disposal method and an underground disposal facility that can dispose of waste while suppressing costs in a relatively low-strength ground in a deep underground. To do.
[0007]
[Means for Solving the Problems]
In the underground disposal method according to the first aspect of the present invention, a waste storage space is formed in the ground while applying an internal pressure by means of an internal pressure introduction means during construction, and a lining material for maintaining airtightness on the inner wall of the storage space the in affixed, the inside of the reservoir space pressure to支保the surrounding ground of the storage space by the action of the, and the internal pressure the while applying a pressure to the storage space by the introducing means the storage space by the pressure introducing means, The waste is carried in through a passage having an air lock function, and after the completion of the carry-in of the waste, a backfill material that fills a gap in the storage space is introduced into the storage space, and then the storage space is closed. It is characterized by that.
[0008]
When waste such as low-level radioactive waste is sequestered underground, finally, the waste is carried into the storage space, and then the back-up material is filled to close the storage space. Therefore, it is sufficient to ensure the stability of the natural ground in the stage from the stage where the storage space is being constructed until it is closed (during operation). Therefore, in the first aspect of the invention, the surrounding ground is supported by applying the internal pressure to the storage space by the internal pressure introducing means during construction and operation, so that even if a large-scale support is not constructed, The mountain stability is ensured.
[0009]
The underground disposal method of the invention of claim 2 is characterized in that, in claim 1, a backfilling material is placed outside the lining material.
[0010]
The underground disposal method of the invention of claim 3 is characterized in that, in claim 1, drainage means for draining groundwater in the ground is provided outside the lining material.
[0011]
The underground disposal method of the invention of claim 4 is the drainage means according to claim 1, wherein a backfilling material is placed outside the lining material, and groundwater in the ground is drained at a boundary portion between the backfilling material and the ground. It is characterized by providing.
[0012]
The underground disposal method of the invention of claim 5 is characterized in that, in any one of claims 1 to 4, when the waste is carried into the storage space, the storage space is ventilated.
[0013]
The underground disposal method of the invention of claim 6 is characterized in that, in any one of claims 1 to 5, the internal pressure of the storage space is managed after the storage space is closed.
[0014]
The underground disposal facility according to the invention of claim 7 is a waste storage space formed in the ground, a lining material affixed to the inner wall of the storage space for airtightness, during construction of the storage space and An internal pressure introducing means for supporting the surrounding ground of the storage space by applying an internal pressure to the storage space during operation until the waste is completely carried into the storage space; and for introducing the waste into the storage space And a passage having an air lock function.
[0015]
The underground disposal facility of the invention of claim 8 is characterized in that, in claim 7, a backfill material is placed outside the lining material.
[0016]
The underground disposal facility of the invention of claim 9 is characterized in that, in claim 7, drainage means for draining groundwater in the ground is provided outside the lining material.
[0017]
The underground disposal facility according to the invention of claim 10 is the drainage means according to claim 7, wherein a backfilling material is placed outside the lining material, and groundwater in the ground is drained at a boundary portion between the backfilling material and the ground. It is characterized by providing.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an underground disposal facility, and FIG. 2 is a configuration diagram of an inner wall 2 of a storage space. This facility includes a waste storage space 1 formed in the ground E, a lining material 2A attached to the inner wall 2 of the storage space 1 for airtightness, and a back surface placed outside the lining material 2A. In the storage space 1 during the construction and operation of the storage space 1, the embedded concrete (backing material) 2B, the drainage pipe (drainage means) 2C disposed at the boundary between the backfilling concrete 2B and the ground E An internal pressure introducing means (not shown) that supports the surrounding ground of the storage space 1 by applying the internal pressure P, and an access tunnel (passage) 8 having an air lock function for carrying waste into the storage space 1 It has.
[0019]
The access tunnel 8 having an air lock function is provided with double doors (plugs) 6B and 6C and a pressure adjusting chamber 9 sandwiched between the doors 6B and 6C. The access tunnel 8 is used for access during construction, and is also used for ventilation during construction and operation and as a passage for transporting waste. Further, an access tunnel 5 with another door (plug) 6 </ b> A is also provided in the lower part of the storage space 1.
[0020]
In order to isolate and dispose of waste underground, first, a waste storage space 1 is formed in the ground E, and a lining material 2A for airtightness is attached to the inner wall 2 of the storage space 1. At that time, in accordance with the process, a drain pipe 2C is provided on the back side of the lining material 2A, and backfill concrete 2B is placed on the back side of the lining material 2A. The drain pipe 2C is positioned at the boundary between the backfill concrete 2B and the ground E.
[0021]
Then, during the construction of the storage space 1 and during the operation until the waste is brought in, the internal pressure P is applied to the inside of the storage space 1 by the internal pressure introducing means, and the surrounding ground of the storage space 1 is supported. In the storage space 1, the waste is carried in via the access tunnel 8 having an air lock function, and the backfilling material for filling the gap in the storage space 1 in the storage space 1 after the completion of the loading of the waste. After introducing (not shown), the storage space 1 is closed.
[0022]
In addition, when gas is generated from the waste in the storage space 1 during construction or operation, ventilation is performed through the access tunnels 5 and 8 for safety. In addition, when gas pressure (storage pressure) is generated in the storage space 1 after the storage space 1 is closed, the internal pressure is managed so that the internal pressure does not increase excessively. By doing in this way, stability of the storage space 1 can be maintained in any period during construction, operation, and storage.
[0023]
Here, the lining material 2 </ b> A also functions to prevent leakage of stored items outside the storage space 1. As the material of the lining material 2A, it is preferable to use carbon steel or stainless steel in consideration of the influence of hot water at a high temperature.
[0024]
The drain pipe 2C functions to prevent the groundwater pressure from acting on the lining material 2A excessively during construction or when the storage space 1 is depressurized. In addition, when storing waste that generates gas when in contact with water, it is also useful for preventing the generation of gas during operation.
[0025]
In addition, the backfill concrete 2B smoothly transmits the internal pressure of the storage space 1 (including the storage pressure in addition to the internal pressure applied during construction and operation) to the ground E so as not to cause local deformation in the lining material 2A. Fulfills the function of Moreover, since the high pressure (storage pressure) acts on the drain pipe 2C during storage, the drain pipe 2C is protected.
[0026]
In this way, when waste such as low-level radioactive waste is isolated and disposed underground, finally, after the waste is carried into the storage space 1, it is filled with a backfill material, and the storage space 1 Will be closed. Therefore, it is sufficient to ensure the stability of natural ground in the stage (under construction and operation) until it is closed. Therefore, as described above, during construction and operation, the surrounding ground is supported by applying the internal pressure P to the storage space 1 by the internal pressure introducing means . By doing in this way, even if it does not construct a large-scale support work, it can dispose of waste, ensuring the stability of a natural ground.
[0027]
For example, when constructing a dome-shaped underground disposal facility with a diameter of 30m, if an internal pressure of 0.5MPa and 1.0MPa is applied, a concrete compressive strength of 6MPa will support a thickness of 0.7m and 1.5m, respectively. Therefore, the concrete thickness (support work) can be reduced by that much, and the construction cost can be reduced.
[0028]
As shown in FIG. 1, the storage space 1 is shaped like a silo with a hemispherical upper part and a cylindrical peripheral wall, or a semicircular part like the one shown in FIGS. Or tunnel type. 3 and 4, sprayed concrete 12 is applied to the inner wall of the storage space 11, a sealing material 13 is disposed as a lining material, and backfill concrete 14 is placed behind the sealing material 13. It has a structure.
[0029]
【The invention's effect】
As described above, according to the inventions of claims 1 and 7, the surrounding ground is supported by applying the internal pressure to the storage space by the internal pressure introducing means during construction and operation. The stability of the natural ground can be maintained without constructing support works. Therefore, even in the underground with a relatively low strength in the underground with a large depth, waste can be isolated and disposed underground while suppressing costs, and the applicability of the disposal facility is expanded. In addition, since it can be disposed of at a large depth, isolation and safety are enhanced. In addition, since the inside of the storage space is made higher than the outside, there is no entry into the groundwater storage space, and it is possible to prevent the waste during operation from coming into contact with water and generating gas. Therefore, the ventilation facility can be made small, and the economy can be improved. In addition, since the storage space is shielded from the outside by the lining material, it is possible to easily take measures against unexpected gas generation from the waste.
[0030]
According to the inventions of claims 2 and 8, by injecting the backfilling material into the back side of the lining material, the internal pressure of the storage space (including the storage pressure in addition to the internal pressure applied during construction and operation) can be smoothly applied to the ground. It is possible to transmit and prevent local deformation of the lining material.
[0031]
According to the third and ninth aspects of the present invention, by providing drainage means outside the lining material, it is possible to prevent the groundwater pressure from acting on the lining material excessively during construction or during storage with reduced internal pressure. it can. In addition, when storing waste that generates gas when in contact with water, generation of gas during operation can be prevented.
[0032]
According to the fourth and tenth aspects of the present invention, the internal pressure of the storage space (including the internal pressure applied during construction and operation) is smoothly applied to the ground by injecting the backfill material into the back side of the lining material. It is possible to transmit and prevent local deformation of the lining material. Further, by providing the drainage means outside the lining material, it is possible to prevent the groundwater pressure from acting on the lining material excessively during construction or during storage with reduced internal pressure. In addition, when storing waste that generates gas when in contact with water, generation of gas during operation can be prevented. Moreover, the drainage means can be protected from the storage pressure by providing the drainage means at the boundary portion between the backfill material and the ground.
[0033]
According to the invention of claim 5, when the waste is carried into the storage space, the inside of the storage space is ventilated, so that it can be safely operated even when gas is generated from the waste.
[0034]
According to the invention of claim 6, since the internal pressure of the storage space is managed after the storage space is closed, it is possible to prevent an excessive internal pressure from being applied to the lining material even when waste gas is generated. , Storage space stability can be maintained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an underground disposal facility according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of an inner wall of the facility.
FIG. 3 is a perspective view showing a schematic configuration of another embodiment of the present invention.
FIG. 4 is a cross-sectional view of another embodiment.
[Explanation of symbols]
E Ground 1 Storage space 2 Inner wall 2A Lining material 2B Backfill concrete (backfill material)
2C Drainage pipe (drainage means)
8 Access tunnel (passage with air lock function)
11 Storage space 13 Sealing material (lining material)
14 Backfill concrete (backfill material)

Claims (10)

While applying a pressure by pressure introducing means into the construction, to form a storage space for waste in the ground, by sticking a lining material for airtightness on the inner wall of the storage space, said storage by said pressure introducing means and支保the surrounding ground of the storage space by the action of internal pressure in the space, and the while the action of internal pressure in the storage space by the internal pressure introducing means in the interior of the storage space, waste through a passage having an air lock function And then introducing a backfilling material that fills the voids in the storage space into the storage space after completion of the transport of the waste, and then closing the storage space. .   2. The waste disposal method according to claim 1, wherein a backfilling material is placed outside the lining material.   2. The waste disposal method according to claim 1, wherein a drainage means for draining groundwater in the ground is provided outside the lining material.   2. The waste underground according to claim 1, wherein a backfill material is placed outside the lining material, and a drainage means for draining groundwater in the ground is provided at a boundary portion between the backfill material and the ground. Disposition method.   The waste disposal method according to claim 1, wherein when the waste is carried into the storage space, the storage space is ventilated.   The method for underground disposal of waste according to any one of claims 1 to 5, wherein the internal pressure of the storage space is managed after the storage space is closed. A waste storage space formed in the ground, a lining material affixed to the inner wall of the storage space for airtightness , and during the construction of the storage space and until the waste has been carried into the storage space An internal pressure introducing means for supporting the surrounding ground of the storage space by applying an internal pressure to the storage space during the operation of the operation, and a passage having an air lock function for carrying waste into the storage space. An underground waste disposal facility characterized by comprising.   The waste disposal facility according to claim 7, wherein a backfilling material is placed outside the lining material.   The waste disposal facility according to claim 7, wherein drainage means for draining groundwater in the ground is provided outside the lining material.   The waste material according to claim 7, wherein a backfilling material is placed outside the lining material, and a drainage means for draining groundwater in the ground is provided at a boundary portion between the backfilling material and the ground. Underground disposal facility.

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