Geological disposal facility and waste body package

Abstract

To provide a geological disposal facility capable of efficiently transporting a waste body package, and to provide the waste body package.SOLUTION: A geological disposal facility 1 comprises: a disposal tunnel 21 in which a cylindrical waste body package 11 containing radioactive waste is disposed in a horizontal orientation; and a friction reduction part 60 which reduces friction between a cylindrical side surface 11a of the waste body package 11 moving independently within the disposal tunnel 21 and an internal surface 21a of the disposal tunnel 21. The friction reduction part 60 includes: a plurality of balls 61 provided on the cylindrical side surface 11a and rolling on the internal surface 21a; or a plurality of balls 61 provided on the internal surface 21a and rolling on the cylindrical side surface 11a.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a geological disposal facility and waste packaging. [Background technology]

[0002] A known technology in this field is the geological disposal facility described in Patent Document 1 below. In this geological disposal facility, waste transported by sea is placed in a storage container at a port facility and processed as a waste package. The waste package is transported from the surface facility to the underground facility by a pneumatic conveying system, and then transported to the disposal tunnel via the main tunnel. After arriving at the disposal tunnel, the waste package is received by a dedicated transport vehicle or device and directed toward the entrance of the disposal tunnel using a turntable. Finally, the waste package is pushed into the disposal tunnel and placed in a predetermined position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-286451 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned geological disposal facility, the waste package does not always move smoothly toward the back of the disposal tunnel after being pushed into the disposal tunnel. Therefore, the transport efficiency of the waste package 11 within the facility is not necessarily good. An object of the present invention is to provide a geological disposal facility and a waste package that can transport waste packages efficiently. [Means for solving the problem]

[0005] The gist of the present invention lies in the following [1] to [4].

[0006] [1] A geological disposal facility for the geological disposal of radioactive waste, comprising: a disposal tunnel in which a cylindrical waste package containing the radioactive waste is placed and disposed of in a horizontal manner; and a friction reduction unit that reduces friction between the cylindrical side surface of the waste package, which moves independently within the disposal tunnel, and the inner wall surface of the disposal tunnel, wherein the friction reduction unit has a plurality of rolling elements provided on the cylindrical side surface and rolling on the inner wall surface, or a plurality of rolling elements provided on the inner wall surface and rolling on the cylindrical side surface.

[0007] [2] A geological disposal facility as described in [1], wherein the friction reduction section has a plurality of ball transfer units embedded in the cylindrical side surface of the waste package or the inner wall surface of the disposal tunnel, the balls serving as the rolling elements.

[0008] [3] A cylindrical waste package containing radioactive waste that is placed horizontally in a disposal tunnel of a geological disposal facility and disposed of, the waste package having a plurality of rolling elements attached to the side of the cylinder that roll on the inner wall surface of the disposal tunnel.

[0009] [4] The waste package according to [3], having a plurality of ball transfer units embedded in the cylindrical side surface and including balls as the rolling elements. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a geological disposal facility and a waste package that are capable of efficiently transporting the waste package. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a geological disposal facility for radioactive waste. [Figure 2] FIG. 1 is a cross-sectional perspective view of a waste package. [Figure 3] FIG. 1(a) is a diagram showing an example of a disposal section with a dead-end layout, and FIG. 1(b) is a diagram showing an example of a disposal section with a panel layout. [Figure 4]1(a) is a cross-sectional view showing a vertically placed stationary system, and FIG. 1(b) is a cross-sectional view showing a horizontally placed stationary system. [Figure 5] FIG. 2 is a cross-sectional view showing a schematic diagram of the transport route of the waste package from the ground facility to the emplacement position. [Figure 6] (a) is an enlarged horizontal cross-sectional view of the vicinity of the junction between the access tunnel and the disposal tunnel, and (b) is a vertical cross-sectional view of the junction. [Figure 7] FIG. 1(a) is a perspective view showing a state in which the first transporting carriage and the waste body package are separated, and FIG. 1(b) is a cross-sectional view showing a state in which the waste body package is loaded onto the first transporting carriage. [Figure 8] 1(a) is a cross-sectional view showing the state of the vicinity of the connection part during the transportation of the waste package, and FIG. 1(b) is a cross-sectional view showing the state of the disposal tunnel during the transportation of the waste package. [Figure 9] (a) is an oblique view showing the appearance of the waste package, (b) is a cross-sectional view showing the vicinity of the cylindrical side surface of the waste package, and (c) is a cross-sectional view showing the vicinity of the inner wall surface of the disposal tunnel. [Figure 10] 10(a) to 10(c) are cross-sectional views showing modified examples of the connecting tunnel and the disposal tunnel. [Figure 11] 10(a) to 10(c) are diagrams showing modified examples of the friction reducer. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a geological disposal facility and a waste package according to the present invention will be described in detail with reference to the drawings.

[0013] As shown in FIG. 1 , the geological disposal facility 1 for radioactive waste in this embodiment comprises an underground disposal compartment 3 where radioactive waste is disposed of, and an aboveground facility 5. The disposal compartment 3 is located at a depth of 300 m or more underground. The geological disposal facility 1 further comprises access tunnels 7a and 7b and a connecting tunnel 9 as tunnels connecting the aboveground facility 5 and the disposal compartment 3. The access tunnel 7a is a vertical shaft extending vertically downward from the aboveground facility 5, and the access tunnel 7b is an inclined shaft extending spirally downward from the aboveground facility 5. Note that the access tunnel 7b may also be a linear inclined shaft. The lower ends of the access tunnels 7a and 7b are connected to the connecting tunnel 9, and the disposal compartment 3 extends to the side of the connecting tunnel 9. The disposal compartment 3 extends over an area of, for example, approximately 500 m x 1,000 m.

[0014] FIG. 2 shows an example of a waste package 11 to be disposed of in the disposal area 3. The waste package 11 is a module containing radioactive waste to be disposed of and is also called a PEM (Pre-Fabricated Engineered Barrier System Module). The waste package 11 is cylindrical, for example, with a diameter of approximately 2 to 3 m and an axial length of approximately 3 to 4 m, and weighs, for example, approximately 30 tons. The waste package 11 includes a waste package 12, a buffer material 13 made primarily of bentonite that surrounds the waste package 12, and a steel storage container 14 that further covers the buffer material 13. The waste package 12 includes a cylindrical stainless steel canister 12a and a cylindrical thick-walled steel overpack 12b in which the canister 12a is hermetically contained. The canister 12a contains vitrified high-level radioactive waste to be disposed of. The waste package 11 is fabricated in the above-ground facility 5.

[0015] The layout of the disposal compartment 3 can be of two types: a "dead-end" type and a "panel" type. Either layout may be adopted for the geological disposal facility 1. As shown in an example in Figure 3(a), a disposal compartment 3 with a dead-end layout has multiple disposal tunnels 21 branching off from an access tunnel 9. Waste packages 11 are placed in the disposal tunnels 21 for disposal. One end of the disposal tunnel 21 is connected to the access tunnel 9, and the other end of the disposal tunnel 21 is a dead end. As shown in an example in Figure 3(b), a disposal compartment 3 with a panel layout has multiple disposal tunnels 21 similar to those described above, and main tunnels 23 that are arranged around the multiple disposal tunnels 21 and connected to the access tunnel 9. One end of each disposal tunnel 21 is connected to the access tunnel 9, and the other end is connected to the main tunnel 23. In general, the "main tunnel" may be included in the "access tunnel" category.

[0016] There are two possible emplacement methods for waste packages 11 in the disposal tunnel 21: a "vertical placement method" and a "horizontal placement method." Either emplacement method may be adopted in the geological disposal facility 1. As shown in an example in Figure 4(a), in the vertical placement method, a number of disposal holes 31 are drilled at predetermined intervals in the bottom of the disposal tunnel 21, and one waste package 11 is placed in each disposal hole 31. The waste package 11 to be disposed of is moved within the disposal tunnel 21 by a predetermined transportation means to the position of a predetermined disposal hole 31 and placed in that disposal hole 31. The space above the waste package 11 is then backfilled with backfill material 33 or the like to close the disposal hole 31, thereby completing the disposal.

[0017] As shown in an example in Figure 4(b), in the horizontal placement method, a large number of waste packages 11 are placed in a row coaxially along the cylindrical axis with their cylindrical axes facing the longitudinal direction of the disposal tunnel 21. A spacer 10 of the same diameter as the waste package 11 is sandwiched between adjacent waste packages 11. The waste package 11 to be disposed of is inserted from the access tunnel 9 into the disposal tunnel 21 in the above-mentioned orientation, and moved within the disposal tunnel 21 by a predetermined moving means. The waste package 11 is then placed at the emplacement position where it hits a spacer 10 previously installed within the disposal tunnel 21, thereby completing the disposal. Note that the spacer 10 may be omitted, in which case the waste packages 11 are placed in the disposal tunnel 21 so that their end faces are directly butted against each other. In this emplacement method, the waste package 11 inserted into the disposal tunnel 21 from the access tunnel 9 is moved within the disposal tunnel 21 by a predetermined moving means, and is placed at the position where it hits another waste package 11 that has already been placed, thereby completing the disposal.

[0018] In this embodiment, the layout of the disposal section 3 is a dead-end type layout, and the emplacement method of the waste package 11 is a horizontal placement method.

[0019] Next, we will explain the transportation system 40 that transports the waste package 11 produced in the ground facility 5 to the emplacement position. Figure 5 is a cross-sectional view that schematically shows the transportation route of the waste package 11 from the ground facility 5 to the emplacement position. In the following explanation, when we simply say "upstream / downstream", we mean upstream / downstream of the transportation of the waste package 11 by the transportation system 40.

[0020] As shown in Figure 5, the transportation system 40 includes a transport unit 41 that transports the waste package 11 within the access tunnel 7a, a transport unit 42 that transports the waste package 11 within the connecting tunnel 9 (transport tunnel), and a transport unit 43 that transports the waste package 11 within the disposal tunnel 21. The transport unit 41 is configured, for example, with a known pneumatic transport device. For example, the transport unit 41 includes the access tunnel 7a that functions as a pneumatic transport pipeline, and a pneumatic transport capsule 45 that carries the waste package 11 and moves up and down within the access tunnel 7a by pneumatic transport. The transport unit 42 includes the connecting tunnel 9 that functions as a pneumatic transport pipeline, and a first transport vehicle 47 that moves within the connecting tunnel 9 by pneumatic transport.

[0021] The transport section 43 is equipped with a disposal tunnel 21 that moves the waste package 11 alone to the emplacement position. The disposal tunnel 21 has a downward slope that descends from the connection section 55 with the access tunnel 9 toward the tip. This downward slope allows the waste package 11 to move within the disposal tunnel 21 under its own weight. The transport section 43 also has a friction reducer 60 that reduces friction between the inner wall surface of the disposal tunnel 21 and the cylindrical side surface of the waste package 11. Details of the friction reducer 60 will be described later.

[0022] In addition, the transportation system 40 is provided with blowers at appropriate locations to generate airflows for air transport, but illustrations and descriptions of these blowers are omitted as appropriate. One such blower, blower 51, is provided, for example, at the most upstream portion of the connecting tunnel 9. The blower 51 controls the airflow in the connecting tunnel 9 by remote control, for example, from the ground facility 5, and controls the movement of the first transport vehicle 47 in the connecting tunnel 9 through this airflow control. For example, the blower 51 sends air from the most upstream portion of the connecting tunnel 9, thereby imparting a propulsive force toward the downstream side to the first transport vehicle 47, causing it to travel downstream. The blower 51 also draws air from the most upstream portion of the connecting tunnel 9, thereby imparting a propulsive force toward the upstream side to the first transport vehicle 47, causing it to travel upstream. Such air transport methods are well known, so further detailed description will be omitted.

[0023] The configuration of the above-mentioned transport sections 42, 43 will be further explained. Figure 6(a) is a horizontal cross-sectional view showing the vicinity of the connection 55 between the access tunnel 9 and the disposal tunnel 21, and Figure 6(b) is a vertical cross-sectional view of the connection 55. As shown in the figure, the access tunnel 9 comprises a main tunnel 9a and a plurality of branch tunnels 9b formed so as to deviate laterally from the main tunnel 9a. The branch tunnels 9b are access roads for entering each disposal tunnel 21 from the main tunnel 9a, and the same number of branch tunnels 9b as the number of disposal tunnels 21 are provided at equal intervals. The downstream end of each branch tunnel 9b is connected to the upstream end of the disposal tunnel 21. The main tunnel 9a and the branch tunnels 9b each have a circular cross-section with a diameter of, for example, approximately 5m.

[0024] The disposal tunnel 21 has a smaller diameter than the connecting tunnel 9, and is connected coaxially to the branch tunnel 9b. The disposal tunnel 21 has a circular cross section with a diameter of, for example, about 3 m. Due to the difference in diameter between the branch tunnel 9b of the connecting tunnel 9 and the disposal tunnel 21, a step 56 is formed at the connection part 55. At the connection part 55, the branch tunnel 9b and the disposal tunnel 21 are connected so that the extension directions of the branch tunnel 9b and the disposal tunnel 21 at the connection part 55 coincide.

[0025] Additionally, a movable air gate 53 is installed within the main road 9a to control the air transport of the first transport vehicle 47. The air gate 53 is arranged so as to substantially block the cross section of the main road 9a and is movable in the upstream and downstream directions within the main road 9a. For example, if the air gate 53 is positioned within the main road 9a slightly downstream of a predetermined branch road 9b, the first transport vehicle 47 traveling along the main road 9a from upstream will be guided to deviate into that branch road 9b. In this manner, the position of the air gate 53 can determine which branch road 9b and disposal tunnel 21 the first transport vehicle 47 will be directed to. The air gate 53 may be movable within the main road 9a by airflow control using a blower 51. Alternatively, the air gate 53 may be movable within the main road 9a by a predetermined drive mechanism.

[0026] As shown in FIG. 7(a), the first transport vehicle 47 in the transport section 42 includes a main body 47a and guide wheels 47c. The main body 47a is cylindrical, with its axis extending in the upstream / downstream direction (the direction of movement of the first transport vehicle 47). A through-hole 47d is formed in the center of the main body 47a, penetrating the main body 47a in the upstream / downstream direction. The through-hole 47d is cylindrical and coaxial with the connecting tunnel 9, and has approximately the same diameter as the disposal tunnel 21. The internal space of the through-hole 47d functions as a storage space for storing waste packages 11. The guide wheels 47c are provided on the upstream and downstream end faces of the main body 47a, with multiple guide wheels 47c arranged circumferentially. The wheels 47b roll on the inner wall surfaces of the connecting tunnel 9 to guide the smooth movement of the first transport vehicle 47. The main body 47a is provided so as to substantially close the cross section of the connecting tunnel 9, and the end face of the main body 47a receives the air flow for driving the first transport vehicle 47 by the pneumatic transport system.

[0027] The first transport vehicle 47 can carry the waste package 11 in a separable state. More specifically, as shown in Fig. 7(b), the waste package 11 is stored in the through-hole 47d of the first transport vehicle 47 with the cylindrical axis of the waste package 11 facing the longitudinal direction of the access tunnel 9. The waste package 11 can slide in the axial direction within the through-hole 47d, but is fixed in place within the through-hole 47d by a locking mechanism 47e including, for example, a locking pin.

[0028] A transportation method using the transportation system 40 as described above will be described. The waste package 11 produced in the ground facility 5 is transported downward through the access tunnel 7a by the transport unit 41 (Fig. 5). At the relay point 8, which is the connection between the access tunnel 7a and the connecting tunnel 9, the waste package 11 is transferred from the transport unit 41 to the transport unit 42. Specifically, as shown in Fig. 7, the waste package 11 is transferred from the air transport capsule 45 to the first transport vehicle 47, i.e., stored in the through hole 47d of the first transport vehicle 47.

[0029] Thereafter, as shown in FIG. 6(a), in the connecting tunnel 9, the first transport vehicle 47 travels downstream along the main road 9a under the airflow control of the blower 51 and enters a predetermined branch road 9b set by the air gate 53. Then, as shown in FIG. 8(a), the first transport vehicle 47 hits a step 56 (stopper) at the connecting section 55 and stops. In this state, the airflow control by the blower 51 continues, and the first transport vehicle 47 is pressed against the step 56 by the airflow. Then, the locking mechanism 47e releases the waste package 11 from its position by remote control from, for example, the ground facility 5. Then, the waste package 11 is subjected to the airflow within the through-hole 47d, and is pushed downstream through the through-hole 47d and transferred to the disposal tunnel 21. Here, since the through-hole 47d and the disposal tunnel 21 have the same diameter and are positioned concentrically, the waste package 11 is smoothly transferred from the through-hole 47d to the disposal tunnel 21. Meanwhile, the first transport vehicle 47, from which the waste package 11 has been separated, is returned to the relay site 8 by airflow control using the blower 51. At this time, a lid for closing the through-hole 47d may be provided so that the first transport vehicle 47 can fully receive the airflow from the blower 51.

[0030] As shown in Figure 8(b), the waste package 11 that has been transferred to the disposal tunnel 21 moves independently under its own weight through the downwardly sloping disposal tunnel 21 with its cylindrical axis oriented in the longitudinal direction of the disposal tunnel 21 until it hits the spacer 10 that has been installed earlier and stops. The position where the waste package hits the spacer 10 is designated as the emplacement position 11p, and the waste package 11 is placed horizontally, thereby completing the disposal of the waste package 11. Note that as the waste package 11 moves through the disposal tunnel 21, the air ahead of the waste package 11 in the direction of movement is compressed, and the compressed air gradually flows out behind the waste package 11 through the gap between the waste package 11 and the disposal tunnel 21. This phenomenon reduces the movement speed of the waste package 11 and reduces the impact when it collides with the spacer 10.

[0031] Next, the friction reduction section 60 between the waste package 11 and the disposal tunnel 21 will be described. As shown in Figures 9(a) and 9(b), the friction reduction section 60 includes a large number of balls 61 (rolling elements) provided on the cylindrical side surface 11a of the waste package 11. Note that the balls 61 are not shown in Figure 2.

[0032] Specifically, a large number of ball transfer units 63 are embedded near the cylindrical side surface 11a of the waste package 11. Each ball transfer unit 63 includes a housing 65 embedded in the cylindrical side surface 11a and the balls 61 that are rotatably held in the housing 65 and protrude slightly from the cylindrical side surface 11a. The housing 65 is embedded, for example, at a position on the front surface side of the storage container 14 (FIG. 2) of the waste package 11. Such ball transfer units 63 are regularly installed over the entire cylindrical side surface 11a. The arrangement and number of ball transfer units 63 on the cylindrical side surface 11a may be appropriately determined based on the weight of the waste package 11, the specifications of the ball transfer units 63, etc.

[0033] When the waste package 11 moves independently within the disposal tunnel 21, the balls 61 slightly protruding from the cylindrical side surface 11a roll on the inner wall surface 21a (Fig. 8) of the disposal tunnel 21, thereby reducing friction between the inner wall surface 21a and the cylindrical side surface 11a. A commercially available ball transfer unit may be used as the ball transfer unit 63.

[0034] 9(c), the ball transfer units 63 may be provided on the inner wall surface 21a of the disposal tunnel 21, instead of on the cylindrical side surface 11a of the waste package 11. In this case, the ball transfer units 63 are installed regularly on the inner wall surface 21a over the entire length and circumference of the disposal tunnel 21. In this case, when the waste package 11 moves independently within the disposal tunnel 21, the balls 61 slightly protruding from the inner wall surface 21a roll on the cylindrical side surface 11a of the waste package 11, thereby reducing friction between the inner wall surface 21a and the cylindrical side surface 11a.

[0035] The effects of the above-described geological disposal facility 1 will now be described. Because the access tunnel 9 and the disposal tunnel 21 have different tunnel specifications (such as borehole diameter), the waste package 11 cannot be transported using the same transport equipment. Conventionally, measures such as transferring the waste package 11 between transport equipment have been required. In contrast, in the transportation system 40 of the geological disposal facility 1, the waste package 11 is separably loaded onto the first transport vehicle 47 that travels through the access tunnel 9. Therefore, by separating the waste package 11 from the first transport vehicle 47 at the connection 55 between the access tunnel 9 and the disposal tunnel 21, the waste package 11 can be transported without transfer. In other words, there is no need to transfer the waste package 11 from the transport equipment for the access tunnel 9 to the transport equipment for the disposal tunnel 21.

[0036] Furthermore, at the connecting part 55, the extension directions of the branch tunnel 9b of the access tunnel 9 and the disposal tunnel 21 are aligned. With this configuration, at the connecting part 55, the waste package 11 can be pushed out into the disposal tunnel 21 by controlling the air flow of the blower 51 and the locking mechanism 47e. Therefore, the waste package 11 can be transported efficiently within the geological disposal facility 1.

[0037] At this time, in the connection section 55, the first transport vehicle 47 is pressed against the step section 56 by the air flow control of the blower 51, and the waste package 11 is further pushed out from the first transport vehicle 47 into the disposal tunnel 21 by the air flow control of the blower 51. In this way, the operation of separating the waste package 11 from the first transport vehicle 47 and introducing it into the disposal tunnel 21 can be performed by the air flow control of the blower 51.

[0038] Furthermore, by designing the through-hole 47d and the disposal tunnel 21 to have the same diameter and to align the cross-sectional positions of the through-hole 47d and the disposal tunnel 21, the through-hole 47d and the disposal tunnel 21, which have the same diameter, are arranged concentrically at the connecting portion 55. That is, when viewed from the axial direction (upstream / downstream direction of the transport of the waste package 11), the through-hole 47d at the connecting portion 55 overlaps with the disposal tunnel 21. In this way, when viewed from the axial direction at the connecting portion 55, the outline of the waste package 11 loaded on the first transport vehicle 47 is positioned so as not to extend beyond the outline of the disposal tunnel 21, and therefore the waste package 11 can be smoothly transferred from the first transport vehicle 47 to the disposal tunnel 21.

[0039] Furthermore, the presence of the friction reducer 60 reduces friction between the inner wall surface 21a of the disposal tunnel 21 and the cylindrical side surface 11a of the waste package 11, so that the waste package 11 transferred from the first transport vehicle 47 of the access tunnel 9 to the disposal tunnel 21 moves smoothly within the disposal tunnel 21 and reaches the emplacement position 11p. This allows the waste package 11 to be efficiently transported within the geological disposal facility 1. Furthermore, if the ball 61 of the friction reducer 60 is provided on the waste package 11 side rather than the disposal tunnel 21 side, friction between the waste package 11 and the through-hole 47d of the first transport vehicle 47 is also reduced. Therefore, when the locking mechanism 47e of the first transport vehicle 47 is released, the waste package 11 is smoothly pushed out of the through-hole 47d and transferred to the disposal tunnel 21.

[0040] Furthermore, in order to ensure smooth transportation of the waste package 11 within the disposal tunnel 21, a system in which a dedicated gripping device holds the waste package 11 and transports it within the disposal tunnel 21 is also considered. However, in this case, the diameter of the disposal tunnel 21 needs to be increased to accommodate the gripping device. This would increase the amount of excavated soil in the construction of the disposal tunnel 21, which would result in increased construction costs due to the accompanying increased cost of excavated soil disposal, improved support specifications, and increased amount of backfill soil. In contrast, the friction reducer 60 can be applied even when the waste package 11 is moved independently within the disposal tunnel 21. For example, it would be possible to make the diameter of the disposal tunnel 21 slightly larger than that of the waste package 11. As a result, the required diameter of the disposal tunnel 21 can be reduced, thereby reducing the construction costs of the disposal tunnel 21.

[0041] The present invention can be implemented in various forms, including the above-described embodiment, with various modifications and improvements based on the knowledge of those skilled in the art. It is also possible to configure modified examples by utilizing the technical matters described in the above-described embodiment. The configurations of the respective embodiments may be used in appropriate combination.

[0042] For example, in the above-described embodiment, the layout of the disposal section 3 (dead-end type / panel type) and the transportation method in the disposal tunnel 21 (pneumatic transportation / movement by inclination) may be changed as appropriate. Note that, if the transportation method in the disposal tunnel 21 is pneumatic transportation, the disposal tunnel 21 does not need to be inclined. For example, if the transportation method in the disposal tunnel 21 is pneumatic transportation, the airflow control by the blower 51 continues even after the waste package 11 is transferred from the through-hole 47d to the disposal tunnel 21 by the airflow of the blower 51. The first transport vehicle 47 is then pressed against the step portion 56 by the airflow of the blower 51 and stops there. Meanwhile, the disposal tunnel 21, which has been transferred to the disposal tunnel 21, receives the airflow from the blower 51 through the through-hole 47d of the first transport vehicle 47 and travels downstream within the disposal tunnel 21. Even in this case, the presence of the friction reducer 60 allows the waste package 11 to move smoothly within the disposal tunnel 21 and reach the emplacement position 11p. If the layout of the disposal section 3 is a dead-end type and the transport method in the disposal tunnel 21 is a pneumatic transport method, for example, a duct or the like may be provided to connect the tip of the disposal tunnel 21 with the connecting tunnel 9 in order to properly move the air during pneumatic transport.

[0043] In the above-described embodiment, the access tunnel 9 and the disposal tunnel 21 have a circular cross section as shown in FIG. 10(a), but the present invention is not limited to such a tunnel shape. The cross-sectional shapes of the access tunnel 9 and the disposal tunnel 21 may be horseshoe-shaped as shown in FIG. 10(b) or rectangular as shown in FIG. 10(c). In this case, the cross-sectional shape of the first transport vehicle 47 may be matched to that of the access tunnel 9. In this case, the first transport vehicle 47 may be positioned so that the outline of the waste package 11 loaded on the first transport vehicle 47 does not extend beyond the outline of the disposal tunnel 21 when viewed axially at the connection portion 55. For example, the through-hole 47d provided in the first transport vehicle 47 for loading the waste package 11 may be designed to overlap the disposal tunnel 21 when viewed axially at the connection portion 55.

[0044] 11(a), balls 61 (ball transfer units 63) may be linearly arranged in the axial direction of the cylinder on the cylindrical side surface 11a of the waste package 11. Similarly, balls 61 may be linearly arranged in the longitudinal direction of the tunnel on the inner wall surface 21a of the disposal tunnel 21. Furthermore, the mechanism for rolling the multiple balls 61 is not limited to the ball transfer units 63, and other ball bearing elements may be used. For example, instead of multiple ball transfer units 63, a unit with a structure such as a linear ball slide that circulates the multiple balls 61 within the unit may be used.

[0045] 11(b) and 11(c), rollers 67 (rolling elements) may be used instead of the balls 61. Fig. 11(b) is a cross-sectional view of the vicinity of the rollers 67 taken at a section perpendicular to the cylindrical axial direction of the waste package 11 when the rollers 67 are installed on the cylindrical side surface 11a of the waste package 11, and Fig. 11(c) is a cross-sectional view taken at a section including the cylindrical axis. A large number of rollers 67 are installed on the cylindrical side surface 11a of the waste package 11 or on the inner wall surface 21a of the disposal tunnel 21 so as to roll in the movement direction (axial direction) of the waste package 11 in the disposal tunnel 21. [Explanation of symbols]

[0046] 1...geological disposal facility, 11...waste package, 11a...cylindrical side surface, 21...disposal tunnel, 21a...inner wall surface, 60...friction reduction section, 63...ball transfer unit, 61...ball (rolling element), 67...roller (rolling element).

Claims

1. A geological disposal facility for geological disposal of radioactive waste, a disposal tunnel in which a cylindrical waste package containing the radioactive waste is placed and disposed of in a horizontal manner; a friction reducing section that reduces friction between the cylindrical side surface of the waste package that moves independently in the disposal tunnel and the inner wall surface of the disposal tunnel; The friction reduction portion is A geological disposal facility having a plurality of rolling elements provided on the side surface of the cylinder and rolling on the inner wall surface, or a plurality of rolling elements provided on the inner wall surface and rolling on the side surface of the cylinder.

2. The friction reduction portion is 2. The geological disposal facility according to claim 1, comprising a plurality of ball transfer units, each of which includes a ball as the rolling element and is embedded in the cylindrical side surface of the waste package or in the inner wall surface of the disposal tunnel.

3. A cylindrical waste package containing radioactive waste that is placed horizontally in a disposal tunnel at a geological disposal facility and disposed of, A waste package comprising a plurality of rolling elements provided on the cylindrical side surface and rolling on the inner wall surface of the disposal tunnel.

4. 4. The waste package according to claim 3, further comprising a plurality of ball transfer units each including a ball as the rolling element and embedded in the cylindrical side surface.

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