JP2007203266A - Plug structure of waste burying disposal facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plug structure of a waste burying disposal facility by which the deterioration or density reduction of a shock absorbing material for sealing waste such as radioactive waste are securely prevented, the waste can suitably be subjected to burying disposal. <P>SOLUTION: The plug structure 10 of a waste burying disposal facility B is installed so as to clog a tunnel 2 for subjecting waste to the burying disposal and receives the swelling pressure of a swellable shock absorbing material 3 packed so as to seal waste into the tunnel 2, and comprises: each tunnel lining part 13 formed in such a manner that a plurality of composite segment bodies 11B composed of a segment body 11a formed so as to be a metallic box shape and a swellable clay material 11b are connected so as to cover the inside face of the tunnel 2; each partition part 14 composed of a plurality of composite segments 11C and provided so as to connect with each tunnel lining part 13 and to clog the tunnel 2; and each supporting part 15 composed of rock bolts 15a connected to each tunnel lining part 13 and further fixed into a foundation T at the outside of the tunnel 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plug structure of a waste embedding disposal facility for embedding waste such as radioactive waste.

  For example, it has been studied to bury high-level radioactive waste in a deep underground area exceeding 300 m underground. At this time, the radioactive waste is solidified by mixing with glass, for example, and is disposed in a state in which the solidified glass is sealed with an overpack made of carbon steel or the like to form a waste. Moreover, as shown in FIG.6 and FIG.7, it is equipped with the main mine 1 connected to a substantially underground deep ring, and the disposal mine and the disposal hole (henceforth the disposal mine 2) formed so that it might connect with this main mine 1 Thus, the waste burying disposal facility A is formed, and the waste is disposed in the disposal mine 2. When disposing of the waste in this kind of waste burying disposal facility A, the buffer material 3 for preventing the intrusion of groundwater and suppressing the pressure from the ground T acting on the waste is provided as the disposal tunnel 2. The waste body is covered with the cushioning material 3 and embedded in the waste body.

  For such a buffer material 3, bentonite or bentonite mixed material (bentonite clay material) excellent in swelling property and adsorptivity of radioactive waste is used, and the ground water infiltrated into the disposal tunnel 2 from the ground T comes into contact and swells. Then, by pressing the ground T, further infiltration of groundwater can be prevented, or the permeability coefficient of the cushioning material 3 can be reduced due to swelling to prevent infiltration of groundwater. As a result, radioactive waste can be reliably isolated from the outside.

  On the other hand, when the bentonite clay material is used as the buffer material 3 as described above, the buffer material 3 swells and swells out from the disposal tunnel 2 to the main tunnel 1 due to the swelling pressure. The density of the buffer material 3 that covers the waste body is lowered, and the shielding ability of the groundwater and thus the sealing ability of the radioactive substance is lowered. Moreover, it takes a lot of labor to take out the buffer material 3 that has been swelled in this way and has a reduced density from the disposal tunnel 2 and to install it again at a predetermined density.

For this reason, in this kind of waste burying disposal facility A, for example, the facility that stores high-pressure gas in the underground space disclosed in Patent Document 1 or Patent Document 2 is disposed on the end 2a side of the disposal tunnel 2 It is considered that a concrete plug (blocking plug) 4 for closing the mine shaft 2 is installed to receive the swelling cushioning material 3 and prevent its swelling to prevent a decrease in density.
JP-A-5-213422 JP-A-6-212899

  However, when the above concrete plug 4 is employed, as shown in FIG. 8, in order to obtain a reaction force against the applied swelling pressure, the disposal tunnel 2 is widened to form a notch portion 5. It is necessary to dispose the peripheral part in the part 5 and install the plug 4. When the excavation tunnel 2 is widened to form the notch 5 in this way, a new loosening area T2 is formed outside the loosening area T1 of the ground T generated when excavating the disposal tunnel 2 itself, and These new and old loose regions T1 and T2 are continuous. For this reason, there is a problem that the continuous old and new loose areas T1 and T2 become water paths and the groundwater easily enters the disposal tunnel 2 and the shielding performance of the groundwater is deteriorated.

  Further, the concrete plug 4 has a problem that Ca (calcium) and highly alkaline components are eluted from the cement into the groundwater, and the buffer material 3 is particularly deteriorated by Ca ions. That is, the bentonite is Na-type bentonite that supports Na (sodium) in that it has excellent swelling properties. When this Na-type bentonite comes into contact with Ca ions, Na and Ca are ion-exchanged, and the swelling property is increased. It changes to Ca type bentonite which is inferior to. For this reason, there existed a problem that the swelling property of the buffer material 3 became poor, and the shielding ability of groundwater and by extension, the shielding ability of a radioactive substance were caused.

  In view of the above circumstances, the present invention reliably prevents the deterioration and density reduction of a buffer material that seals waste such as radioactive waste, and can bury waste appropriately. The object is to provide a plug structure for a disposal facility.

  In order to achieve the above object, the present invention provides the following means.

  The plug structure of the waste embedding disposal facility according to the present invention is a swellable cushioning material that is installed so as to close a tunnel for burying and disposing of waste, and is filled so as to seal the waste in the tunnel. A plug structure of a waste burial disposal facility that receives swelling pressure, wherein a plurality of composite segments made of a segment body formed in a metal box shape and a swellable clay material filled in the segment body are formed on the inner surface of the tunnel. Connected to the lining portion, a lining portion formed so as to be covered, a partition wall portion composed of a plurality of the composite segments connected to the lining portion and continuously provided to close the mine shaft And a support portion fixed to the ground outside the mine shaft.

  In the plug structure of the waste embedding disposal facility according to the present invention, it is preferable that the support portion is a friction fixing type lock bolt.

  Furthermore, in the plug structure of the waste embedding disposal facility of the present invention, it is more preferable that the partition wall is formed in a convex cross-sectional arch shape toward the inner side in the axial direction of the mine shaft.

  Moreover, in the plug structure of the waste disposal facility of the present invention, the composite segment of the partition wall is formed in a wedge shape whose width gradually decreases from the inner side in the axial direction of the mine shaft toward the outer side in the axial direction. More desirable.

  Furthermore, in the plug structure of the waste disposal facility of the present invention, the composite segment of the lining part is installed so that the exposed surface of the swellable clay material filled in the segment body faces the inner surface side of the mine shaft It is desirable that

  According to the plug structure of the waste embedding disposal facility of the present invention, the lining portion formed so as to cover the inner surface of the mine shaft, the partition wall portion connected to the lining portion so as to close the mine shaft, Since it is composed of a support part consisting of rock bolts connected to the work part, the swelling pressure acting when the buffer material swells in contact with the groundwater is transmitted from the partition part to the lining part and supported by the support part can do. Thereby, unlike a concrete plug, it is not necessary to widen excavate the tunnel to form a notch, so that the groundwater shielding performance is not lowered.

  In addition, the partition wall part that directly contacts the cushioning material and the lining part that supports the partition part are formed of a composite segment made of a metal segment body and a swellable clay material, that is, no cementitious material is used. The buffer material can be prevented from deteriorating, and the waste can be reliably sealed and disposed of. In addition, even when the bulkhead or lining segment main body corrodes due to contact with groundwater over a long period of time, the groundwater infiltrated from the corroded defective portion contacts the swellable clay material and swells it. The defect portion can be filled with the swelling clay material. This makes it possible to reliably maintain the groundwater shielding ability in the long term.

  Further, in the plug structure of the waste embedding disposal facility according to the present invention, since the support portion is a friction fixing type rock bolt, the plug structure can be configured completely without using cement material, and more reliably. In addition, the buffer material can be prevented from deteriorating.

  Furthermore, in the plug structure of the waste embedding disposal facility of the present invention, the partition wall portion is formed in a convex cross-sectional arch shape toward the inner side in the axial direction of the mine shaft, so that the swelling pressure acting from the buffer material can be surely applied. It can be received by the partition wall and transmitted to the lining part and received by the support part.

  Further, in the plug structure of the waste embedding disposal facility of the present invention, the composite segment of the partition wall is formed in a wedge shape whose width gradually decreases from the inner side in the axial direction of the tunnel toward the outer side in the axial direction. The greater the swelling pressure is applied, the more the integrity of the composite segment of the partition wall is secured, and the swelling pressure can be reliably received.

  Furthermore, in the plug structure of the waste embedding disposal facility of the present invention, the composite segment of the lining part is installed with the exposed surface of the swellable clay material filled in the segment body facing the inner surface side of the mine shaft Even when groundwater penetrates from the ground to the inner surface of the mine in the lining part, the groundwater can be brought into contact with the swellable clay material, and the gap between the lining part and the inner surface of the mineway with the swelling of the swellable clay material Is buried in the pressed state, and it is possible to reliably prevent the groundwater from entering the buffer material through this gap.

  Hereinafter, a plug structure of a waste embedding disposal facility according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. The present embodiment relates to a plug structure of a waste embedding disposal facility for embedding high-level radioactive waste in a bedrock (ground) deep in the depth of, for example, more than 300 m underground.

  As shown in FIG. 1 and FIG. 2, the waste burying disposal facility B of the present embodiment is constructed from the ground toward the deep underground, and is connected to the main tunnel 1 connected to the main tunnel 1 in a substantially annular shape in the deep underground. And a plurality of disposal tunnels (tunnels) 2 in which radioactive waste is disposed, a buffer material 3 filled in the disposal tunnel 2 so as to cover the radioactive waste, and both ends of the disposal tunnel 2 It is comprised from the plug (plug structure) 10 each provided so that the disposal tunnel 2 may be obstruct | occluded by 2a side.

  Here, the radioactive waste to be disposed of is disposed in the state of a waste body in which, for example, a waste liquid with a high radiation level is mixed with glass and solidified, and this glass solid body is sealed with an overpack made of carbon steel or the like. The wastes disposed in the disposal mine 2 in this way are isolated from the biosphere by the natural barrier of the natural ground and the artificial barrier mainly composed of the buffer material 3, and the influence of the radioactive material will affect the human environment in the future. It is disposed of so that there is no.

  As shown in FIGS. 2 and 3, the disposal tunnel 2 has a plurality of arcuate disk-shaped lining segments 11 </ b> A having a curvature radius substantially equal to the curvature radius of the inner surface of the excavation surface on the inner surface of the excavation surface of the ground T. An annular segment ring body 12 that is provided continuously and supports the inner surface of the excavation in the circumferential direction is formed. Moreover, the segment ring body 12 is connected so as to be continuous in the direction of the axis O1 of the disposal mine shaft 2, and a lining for covering and supporting the inner surface of the excavation is formed. The lining is formed by using a composite segment (covering segment) 11A that is substantially the same as the lining portion 13 of the plug 10 of the present embodiment described later.

  The buffer material 3 is bentonite or bentonite mixed material excellent in swelling property and adsorptivity of radioactive waste, and is disposed on both ends 2a side of the lining and the disposal tunnel 2 so as to seal the waste in the disposal tunnel 2. A space S defined by the plug 10 to be installed is filled. The buffer material 3 swells when the groundwater that has entered the disposal tunnel 2 from the ground T comes into contact with it, and the water permeability of the buffer material 3 is greatly reduced along with the swelling, thereby preventing the groundwater from coming into contact with the sealed waste. Further, for example, when the force acting on the waste body is buffered due to the displacement of the ground T, and further, for example, when the waste body is damaged and the radioactive substance is released, the radioactive substance is adsorbed to the outside. Control leakage to

  As shown in FIGS. 2 to 5, the plug 10 of the present embodiment includes a plurality of composite segments 11 </ b> B composed of a steel segment main body 11 a and a bentonite clay material (swelling clay material) 11 b. A lining portion 13 installed annularly in the circumferential direction on the inner surface of the excavation on the 2a side, a partition wall portion 14 composed of a plurality of composite segments 11C in the same manner as the lining portion 13 and provided to close the disposal tunnel 2, The support portion 15 is composed of a plurality of lock bolts 15 a that are connected to the lining portion 13 while penetrating the lining portion 13 and extend into the ground T.

  In the present embodiment, the composite segments 11B and 11C forming the lining portion 13 and the partition wall portion 14 are formed in a steel box shape with the segment main body 11a opened on the upper surface side, and the bentonite clay material 11b is compressed therein. While being filled, it is formed. And in the lining part 13, this composite segment 11B is installed so that the upper surface side which the segment main body 11a opens turns to the excavation inner surface side, ie, the exposed surface 11d of the bentonite clay material 11b faces the excavation inner surface. .

  As shown in FIG. 2, the partition wall portion 14 is formed such that a section along the axis O <b> 1 of the disposal mine 2 has a convex arch shape on the buffer material 3 side (inward in the direction of the axis O <b> 1 of the disposal mine 2). And this partition part 14 is cyclic | annular form which consists of several composite segments 11C arranged in the circumferential direction at the outer peripheral side of the disposal mine shaft 2 by the front view from the axial O1 direction inner side of the disposal mine shaft 2, as shown in FIG. Partition wall body portion 16 and a manhole portion 17 including one composite segment 11C fitted and installed in the inner hole of the partition wall body portion 16 and provided with a manhole 17a.

  The partition wall main body 16 is formed by arranging a plurality of composite segments 11C having a substantially fan shape in parallel with each other in the circumferential direction so that the circumferential width on the radially outer side is larger than the circumferential width on the radially inner side. The outer side in the radial direction of each composite segment 11C is connected to the tip 13a of the lining portion 13 and formed in an annular shape. Moreover, these composite segments 11C are formed in a wedge shape in which the radial and circumferential widths gradually decrease from the inner side toward the outer side in the axis O1 direction of the disposal mine shaft 2. The composite segments 11C adjacent to each other in the circumferential direction of the partition wall main body 16 are integrally coupled to each other with, for example, bolts fastened in a state in which end surfaces facing the circumferential direction are in close contact with each other.

  On the other hand, the manhole portion 17 is composed of one composite segment 11C having a substantially circular shape in a plan view and fitted into an inner hole defined by the radially inner end surfaces of the plurality of composite segments 11C of the partition wall main body portion 16; Similar to the composite segment 11C of the bulkhead main body 16, the disposal tunnel 2 is formed in a wedge shape in which the radial and circumferential widths gradually decrease from the inner side toward the outer side in the direction of the axis O1. And it is fastened, for example with a volt | bolt, in the state which end surfaces closely_contact | adhered to the composite segment 11C of the partition main body part 16. FIG. Further, the manhole portion 17 is provided with a manhole 17a that penetrates from the inner surface to the outer surface of the partition wall portion 14 and has a circular cross section. By the way, the manhole 17a is provided with, for example, a steel lid (not shown) and can be closed. When the waste is disposed of, the manhole 17a is opened and used for carrying in / out of inspection of materials / equipment to / from the disposal tunnel 2. After the disposal of the waste body, it is filled and sealed with, for example, bentonite clay material.

  As shown in FIG. 2, the plurality of lock bolts 15 a constituting the support portion 15 are each made of, for example, an inflatable and highly corrosion-resistant steel pipe 15 b and are connected to the rear end side connected to the composite segment 11 </ b> B of the lining portion 13. The tip end side is arranged on the inner side in the direction of the axis O <b> 1 of the disposal tunnel 2, and extends toward the outer side of the disposal tunnel 2. Further, as shown in FIG. 5A, the lock bolt 15a is mixed with, for example, ethanol while applying pressure to the steel pipe 15b when the steel pipe 15b is inserted into the drilling hole 15c provided in the ground T. When the bentonite mud water (ethanol bentonite) is injected, the cross section of the steel pipe 15b shown in FIG. 5 (b) expands as shown in FIG. 5 (c), and the outer surface thereof is frictionally fixed by being pressed against the inner surface of the hole 15c. The In addition, when ethanol bentonite is filled in the steel pipe 15b in this way, as groundwater enters from the ground T, ethanol and groundwater are replaced and the bentonite swells, and the frictional force between the steel pipe 15b and the ground T increases. Thus, the lock bolt 15a is securely fixed. Further, ethanol bentonite may be interposed between the outer surface of the steel pipe 15b and the inner surface of the drilling hole 15c. In this case, groundwater and ethanol are replaced, and swelling pressure is generated and firmly adhered to the ground T. The lock bolt 15a can be reliably fixed.

  The plug 10 of the waste embedding disposal facility B according to the present embodiment configured as described above forms the lining portion 13 by installing the composite segment 11B so as to cover the inner surface of the disposal tunnel 2, and then the ground T A hole 15c is provided at the same time and a lock bolt 15a is provided to form the support portion 15 fixed to the ground T while being connected to the lining portion 13. Finally, the composite segment 11C is installed so as to close the disposal mineway 2 to form the partition wall 14 and the construction is completed. In the plug 10 of this embodiment provided in this way, unlike the case where a concrete plug is installed, it is not necessary to widen the disposal mine 2 to form the cutout portion 5, and a new loosening region on the ground T Since T2 is not formed, the groundwater shielding performance is not lowered.

  Moreover, when the groundwater which penetrate | infiltrated from the ground T contacts the buffer material 3 sealed in the disposal mine shaft 2 by the plug 10 provided in the both ends 2a side, and this buffer material 3 swells, the buffer material 3 directly. Swelling pressure acts on the partition wall 14 in contact with the wall, and this swelling pressure can be transmitted from the partition wall 14 to the lining portion 13 and received by the lock bolt 15a of the support section 15. At this time, the partition wall portion 14 is formed in a convex arch shape inward in the direction of the axis O1 of the disposal tunnel 2, and the composite segment 11C forming the partition wall portion 14 is formed in a wedge shape, and on the outer peripheral side of the partition wall portion 14 Since the end portion is connected to the tip 13a of the lining portion 13, the composite segment 11C of the partition wall portion 14C is not displaced by the applied swelling pressure, and the swell pressure is reliably received by the partition wall portion 14 for covering. It can be transmitted to and supported by the part 13. Thereby, the density reduction of the swollen buffer material 3 can be prevented and the waste body can be reliably sealed.

  Further, the composite segments 11B and 11C constituting the lining portion 13 and the partition wall portion 14 are formed of a steel segment main body 11a and a bentonite clay material 11b, and the lock bolt 15a of the support portion 15 is a steel pipe 15b and ethanol. Because it is a friction fixing type rock bolt formed from bentonite, that is, since no cement material is used in the plug 10 of the present embodiment, the ground water in contact with the buffer material 3 exhibits alkalinity, Groundwater does not contain a large amount of calcium ions. Thereby, it can prevent that the buffer material 3 deteriorates, and it becomes possible to seal and discard a waste body reliably.

  Moreover, since the lining part 13 is installed with the exposed surface 11d of the bentonite-based clay material 11b facing the inner surface side of the disposal tunnel 2, the groundwater penetrating from the ground of this portion comes into contact with the bentonite-based clay material and swells. And the clearance gap between the lining part 13 and the inner surface of the disposal mine shaft 2 can be filled in a pressed state, and it can prevent reliably that groundwater permeates into the buffer material 3 through this clearance gap. In addition, even when the lining part 13 or the partition wall part 14 is in contact with the groundwater for a long period of time and the segment main body 11a of the composite segments 11B and 11C is corroded, it enters from the corroded defective part. The groundwater thus contacted with the bentonite clay material 11b filled in the segment main body 11a, the bentonite clay material 11b can swell and fill the defective portion. This makes it possible to reliably maintain the groundwater shielding ability in the long term.

  Therefore, according to the plug structure 10 of the waste embedding disposal facility B of the present embodiment, the swelling pressure of the buffer material 3 can be reliably received, the deterioration and the density reduction of the buffer material 3 can be prevented, and the groundwater can be prevented. Since the shielding ability can be reliably maintained for a long period of time, radioactive waste can be reliably isolated over a long period of time.

  As mentioned above, although one embodiment of the plug structure 10 of the waste burying disposal facility B according to the present invention has been described, the present invention is not limited to the above-described one embodiment, and is appropriately changed without departing from the spirit thereof. Is possible. For example, in the present embodiment, the composite segments 11B and 11C forming the lining portion 13 and the partition wall portion 14 are composed of a steel segment main body 11a and a bentonite clay material 11b. May be formed of other metal materials such as cast iron, and the swellable clay material filled in the segment main body 11a is not necessarily limited to the bentonite clay material 11b.

  Further, the lining portion 13 is formed by setting the exposed surface 11d of the bentonite clay material 11b of the composite segment 11B toward the excavation inner surface of the disposal tunnel 2, but the exposed surface of the bentonite clay material 11b. 11d may be installed toward the inside of the disposal tunnel 2, and in this case, a bentonite clay material may be backfilled between the lining portion 13 and the disposal tunnel 2. In the present embodiment, the support portion 15 is the friction fixing type lock bolt 15a. However, the support portion 15 may be, for example, a lock bolt or an anchor fixed to the ground T by a method other than the friction fixing.

  Further, in the present embodiment, the explanation has been made assuming that the waste to be disposed is radioactive waste, but the plug structure 10 of the present invention may be applied to a waste embedding disposal facility for disposing other harmful substances. Is. Further, in the present embodiment, the plug structure 10 is provided on each end 2a side of the disposal tunnel 2, but the disposal is provided at the end of the disposal hole (mine tunnel) closed at one end. It may be used to suppress the expansion of the buffer material filled so as to embed the waste in the hole.

It is a perspective view which shows the waste burial disposal facility which concerns on one Embodiment of this invention. It is sectional drawing which shows the plug structure of the waste burial disposal facility which concerns on one Embodiment of this invention. It is a perspective view which shows the lining part of the plug structure of the waste burial disposal facility of FIG. It is a top view from the mine shaft inner side which shows the partition part of the plug structure of the waste burial disposal facility of FIG. It is a figure which shows the lock bolt of the support part of the plug structure of the waste burying disposal facility of FIG. It is a perspective view which shows the waste burial disposal facility provided with the plugs made from concrete. It is sectional drawing which shows the disposal tunnel of the waste burial disposal facility of FIG. It is sectional drawing which shows the notch formed in the disposal tunnel of FIG.

Explanation of symbols

1 Main tunnel 2 Disposal tunnel (tunnel)
2a End 3 Buffer material 10 Plug (plug structure)
11A Composite segment 11B Composite segment 11C Composite segment 11a Segment body 11b Bentonite clay material (swelling clay material)
11d Exposed surface 13 Covering section 14 Bulkhead section 15 Support section 15a Rock bolt 15b Steel pipe 16 Bulkhead body section 17 Manhole section 17a Manhole A Waste burial disposal facility B Waste burial disposal facility T Ground O1 Axis of disposal tunnel

Claims (5)

A plug structure of a waste burying disposal facility that is installed so as to close a mine shaft for burying waste and receives the swelling pressure of a swellable cushioning material filled so as to seal the waste in the mine shaft. There,
A lining part formed by connecting a segment main body formed in a metal box shape and a plurality of composite segments made of a swellable clay material filled in the segment main body so as to cover the inner surface of the tunnel, A partition wall portion composed of a plurality of the composite segments connected to the lining portion so as to block the mine shaft, and a support portion connected to the lining portion and fixed to the ground outside the mine shaft. A plug structure of a waste burial disposal facility, characterized by comprising: In the plug structure of the waste embedding disposal facility according to claim 1,
A plug structure for a waste burying disposal facility, wherein the support portion is a friction fixing type rock bolt. In the plug structure of the waste embedding disposal facility according to claim 1 or claim 2,
The plug structure of a waste burial disposal facility, wherein the partition wall is formed in a convex cross-sectional arch shape toward the inner side in the axial direction of the mine shaft. In the plug structure of the waste embedding disposal facility according to claim 3,
The plug structure of a waste embedding disposal facility, wherein the composite segment of the partition wall is formed in a wedge shape whose width gradually decreases from the inner side in the axial direction of the tunnel toward the outer side in the axial direction. In the plug structure of the waste embedding disposal facility according to any one of claims 1 to 4,
The composite segment of the lining part is installed such that the exposed surface of the swellable clay material filled in the segment body faces the inner surface side of the mine shaft, the plug of the waste embedding disposal facility, Construction.

Images