JP4492373B2 - Disposal tunnel facility at waste geological disposal site - Google Patents

Description

  The present invention relates to a tunnel shape of a disposal tunnel facility constructed underground of a geological disposal site for radioactive waste or the like generated from nuclear power generation.

  Among the radioactive waste generated from nuclear power generation, high-level radioactive waste is liquid waste separated in the reprocessing process of spent nuclear fuel, and not only has a high level of radioactivity but also continues to have radioactivity for a long period of time. It contains many long-lived radionuclides. Therefore, such high-level radioactive waste is dissolved in a stainless steel canister together with glass raw materials, stabilized as a glass solidified body, stored for several decades for cooling, and then the canister in which the glass solidified body is stored. To be disposed of in a sealed container made of thick steel plate called overpack, and disposed of in a stable formation deeper than 300m underground (determined by law). Yes.

  In this geological disposal, it is currently considered to dig a tunnel (disposal tunnel) deep underground, bury the waste, and then backfill the surrounding area (within the disposal tunnel) with bentonite etc. . In order to demonstrate the safety of this geological disposal, we expect the low permeability of the bedrock itself so that the nuclides contained in the radioactive waste do not reach the world where people live on groundwater. There is a need to ensure that excavated disposal tunnels are backfilled and that there is no water channel that provides an excellent migration path for nuclides.

  A conventionally considered facility shape is that a large number of tunnels are excavated in parallel at the same depth from the viewpoint of workability, safety, and economy to form a single panel. As shown in FIGS. 4 and 5, the high-level radioactive waste geological disposal facility 50 includes an above-ground facility 51 and an underground facility 52. The underground facility 52 is composed of an access tunnel 53 such as a vertical shaft or a tilt shaft connecting the ground and the underground, a disposal tunnel 54 formed by excavation horizontally in parallel in the deep underground, and a main tunnel 55 connected to these disposal tunnels. ing. The disposal tunnel 54 is partitioned and divided into independent horizontal disposal panels, and flexible panel layouts such as distributed layout and multilayer layout are possible according to the geological environmental conditions of the disposal site, and construction and operation are also possible.・ Major closure work can be carried out independently and in parallel.

  In addition, various methods for placing waste in the disposal tunnel 54 have been considered. For example, a disposal hole anchoring method as shown in FIG. 6 (a), as shown in FIG. 6 (b), and the like. There is a disposal tunnel horizontal installation method. In FIG. 6 (a), the disposal hole 56 is vertically drilled from the bottom of the disposal tunnel 54 formed in the rock A as a natural barrier, and a predetermined interval is provided in the tunnel axis direction. In this disposal hole 56, a buffer material (such as bentonite) B that reduces the influence of groundwater and rock pressure is laid as an artificial barrier, and the waste material C placed in the buffer material B is buried. ing. The disposal tunnel 54 is backfilled. In FIG. 6B, the buffer material B is spread in the disposal tunnel 54, and the waste C lying in the buffer material B is buried in the tunnel axis direction at a predetermined interval.

Moreover, there are Patent Documents 1 to 9 as prior art documents related to the present invention. The invention of Patent Document 1 is a method of burying low-level radioactive waste in a tunnel. The invention of Patent Document 2 is a method of embedding a waste body and a buffer material in a disposal hole or a disposal tunnel. In the invention of Patent Document 3, the disposal mine is branched from the main mine at a right angle to transport and place the waste. The invention of Patent Document 4 is a construction method and a geological disposal method such as a disposal tunnel by an air conveyance system. The invention of Patent Document 5 is a disposal method for a tunnel-type disposal facility for low-level radioactive waste. The invention of Patent Document 6 is a stationary structure for placing in a disposal tunnel for high-level radioactive waste. The invention of Patent Document 7 is a placement method in a tunnel-type disposal facility for low-level radioactive waste. In the inventions of Patent Documents 8 and 9, radioactive waste is alternately stored and disposed from a transport vertical shaft or a transport inclined shaft to a storage inclined shaft via a specially shaped buffer.
JP 2004-298822 A JP 2004-286451 A JP 2003-215297 A JP 2003-148097 A JP 2002-340993 A JP 2002-48900 A JP 2002-107493 A Japanese Patent Laid-Open No. 11-223699 JP-A-11-153699

  There are the following problems in the laying method and the horizontal method, which are currently considered waste installation methods.

(1) Standing method (compared to horizontal method)
In the dredging method, it is necessary to dig a disposal hole for disposing the waste body downward from the disposal tunnel developed in a panel shape. Moreover, since the waste body is placed and the buffer material is backfilled using the stationary equipment on the disposal hole for installing the waste body, a wider space is required and the diameter of the tunnel is required to be increased. From these conditions, the dredging method increases the amount of excavated soil, which increases the construction period and costs. Moreover, since the amount of excavated soil increases on the ground, a larger temporary storage yard is required.

(2) Horizontal installation method (compared to the vertical installation method)
In the horizontal installation method, it is difficult to backfill the surrounding area, particularly the upper part, after placing the waste in the disposal tunnel, and there remains a problem in technical reliability. As shown in FIG. 7, various methods such as a block method, a center hole method, a compression method, and a pellet method are considered, but it is difficult to fill the upper part of the waste body, so the possibility that a gap is generated at the top end is denied. It is not possible, and technical reliability is low compared with the laying-down method.

  The present invention has been made in order to solve such problems, and its purpose is to provide a horizontal disposal system for waste bodies that can reduce the amount of excavated soil in a disposal tunnel facility of a geological disposal site such as radioactive waste. Even if there is, it is possible to easily and reliably backfill the upper part of the disposal tunnel, and to provide a disposal tunnel facility for the waste geological disposal site that can ensure the technical reliability of the backfill after the waste is placed There is to do.

The invention according to claim 1 of the present invention is a disposal tunnel facility that is constructed in the underground ground of a waste geological disposal site and is composed of a disposal tunnel in which waste is buried and disposed horizontally. A tilting shaft inclined with respect to the tilt shaft is formed, and an installation table having a horizontal installation surface is formed on the bottom plate in the tilt shaft, and the waste is placed horizontally on the installation table at intervals in the longitudinal direction of the shaft. This is a disposal mine facility of a waste geological disposal site, which is arranged in a substantially horizontal horizontal system, and the space inside the inclined shaft is backfilled with a backfill material (buffer material such as bentonite).

  The present invention is particularly effectively applied to a disposal mine in a geological disposal site for high-level radioactive waste. It can also be applied to geological disposal of other waste. In the present invention, the disposal tunnel is inclined to the extent that the technical reliability of the backfilling after the disposal of the waste can be ensured based on the horizontal disposal system of the disposal body that can reduce the amount of excavated soil. Therefore, the inclination angle of the inclined shaft may be set to an inclination angle that allows the back end material to be easily filled in the top end portion of the disposal tunnel and does not cause a gap at the top end portion.

  Moreover, in the invention which concerns on Claim 1, since the base of an inclined shaft is inclined, the installation base which has a horizontal installation surface with a backfill material is formed on this bottom, and a waste body is installed on this. Thereafter, a backfilling material is disposed around the waste body to backfill the space. Since the top end of the inclined shaft is inclined, the cushioning material can be easily filled in the top end portion, and no gap is formed in the top end portion, so that the technical reliability of backfilling is ensured.

The invention according to claim 2 of the present invention is a disposal tunnel facility that is constructed in the underground ground of a waste geological disposal site, and is composed of a disposal tunnel in which waste is buried and disposed horizontally. The inclined shaft is inclined with respect to the inclined shaft, and a step in the longitudinal direction of the inclined shaft is formed on the bottom plate of the inclined shaft, and an installation table having a horizontal installation surface with a backfill material is formed on the horizontal step portion of the inclined shaft. In the waste geological disposal site, the waste is disposed horizontally or in a substantially horizontal horizontal manner, and the space in the inclined shaft is backfilled with backfill material (buffer material such as bentonite). Disposal tunnel facility.

  The invention according to claim 2 is a case where the bottom plate of the inclined shaft is constructed in a staircase shape in order to maintain the stability of the waste body after placement of the waste body. One step or multiple steps in the longitudinal direction of the shaft are formed on the bottom of the shaft, and an installation table having a horizontal installation surface is formed on the horizontal steps of the stairs with backfill material. Install. Thereafter, a backfilling material is disposed around the waste body to backfill the space. Since the top end of the inclined shaft is inclined, the cushioning material can be easily filled in the top end portion, and no gap is formed in the top end portion, so that the technical reliability of backfilling is ensured.

  A plurality of inclined shafts are excavated in parallel between upper and lower main shafts excavated in parallel at a predetermined distance in the vertical and horizontal directions. It is preferable that the horizontal portion is excavated from the main shaft and the upper and lower horizontal portions are connected by the inclined shaft portion.

Since the present invention is configured as described above, the following effects can be obtained.
(1) Because it is a horizontal type inclined shaft, it can reduce the amount of excavated soil and shorten the construction period and cost compared to the conventional vertical type.
(2) Compared to the conventional dredging method, the amount of excavated soil is reduced, so the temporary storage yard for excavated soil can be narrowed. As a result, geological disposal becomes possible even in narrow land.
(3) Compared with the conventional horizontal placement system, it becomes easier to backfill the top end after placing the waste body, and there is no gap at the top end of the disposal tunnel, improving technical reliability.

  Hereinafter, the present invention will be described based on the illustrated embodiment. This embodiment is an example applied to a disposal tunnel of a geological disposal facility for high-level radioactive waste. FIG. 1 is a vertical sectional view showing an example of a disposal mine shaft according to the present invention, and shows two cases with different inclination angles. FIG. 2 is a vertical sectional view showing another example of a disposal mine shaft according to the present invention, and shows two cases with different inclination angles. FIG. 3 is a perspective view showing an overall image of the disposal tunnel according to the present invention.

  In the embodiment of FIG. 1, the disposal mine 1 in which the waste body C is buried is tilted at an inclination angle θ with respect to the horizontal to form an inclined shaft. A waste body (overpack) C is disposed in the inclined shaft 1 in a horizontal or substantially horizontal manner at a predetermined pitch in the longitudinal direction of the tunnel, and a buffer material (bentonite) as a backfill material is filled in the space in the inclined shaft 1. Etc.) Backfill with B.

  Since the bottom plate 1a of the inclined shaft 1 is inclined, an installation table having a horizontal installation surface is formed on the bottom plate 1a with the buffer material B, and the waste body C is installed thereon. Then, the buffer material B is arrange | positioned around the waste body C, and a space part is refilled. Since the top end 1b of the inclined shaft 1 is inclined, the buffer material B can be easily filled in the top end portion, and no gap is formed in the top end 1b, so that technical reliability of backfilling is ensured. The

  The inclination angle θ can be arbitrarily set within a range in which the technical reliability of backfilling can be ensured without causing a gap at the top end 1b of the inclined shaft 1.

In the embodiment of FIG. 2, a staircase 2 continuous in the longitudinal direction of the shaft is formed on the bottom of the inclined shaft 1, and the waste C is arranged horizontally or substantially horizontally on each step 2 a, By maintaining the lower support surface horizontal, the stability of the waste body C after placement of the waste body is maintained. An installation base having a horizontal installation surface is formed on the horizontal step portion 2a of the staircase 2 with the buffer material B, and the waste body C is installed thereon. The stairs may be one step.

  As in FIG. 1, the space is backfilled with the buffer material B. As in FIG. 1, there is no gap at the top end 1b, and the technical reliability of backfilling is ensured.

  As shown in FIG. 3, the disposal mine shaft 1 by the inclined shaft is excavated and formed in parallel between the main mine shafts 3 and 4, as in the conventional panel system. The main mine shafts 3 and 4 are excavated and formed in parallel at a predetermined distance in the vertical direction and the horizontal direction, and the upper and lower main mine shafts 3 and 4 are connected by the disposal mine shaft 1 by the inclined shaft. It is preferable that the horizontal portions 11a and 11b protrude from the upper and lower main shafts 3 and 4 and the inclined shaft portion 11c is provided between the horizontal portions 11a and 11b.

  In addition, although the above demonstrated the case where it applied to the geological disposal site of radioactive waste, it is applicable also to the geological disposal of other waste.

It is a vertical sectional view showing an example of a disposal tunnel according to the present invention, and shows two cases with different inclination angles. It is a vertical sectional view showing other examples of a disposal mine shaft according to the present invention, and shows two cases with different inclination angles. It is a perspective view which shows the whole image of the disposal mine shaft which concerns on this invention. It is a fragmentary sectional perspective view which shows the geological disposal facility of a high level radioactive waste. It is a top view which shows the disposal panel by the conventional disposal tunnel. It is a perspective view which makes the cross section the placement method of a waste body, (a) is a disposal hole dredging system, (b) is a disposal tunnel horizontal installation system. It is a vertical sectional view which shows the difficulty of backfilling around the waste body at the time of horizontal placement in comparison with that at the time of standing.

Explanation of symbols

1 ... Slope shaft (disposal tunnel)
DESCRIPTION OF SYMBOLS 1a ... Bottom board 1b ... Top end 2 ... Stairs 2a ... Each step (horizontal step part)
3 ... Upper main tunnel 4 ... Lower main tunnel 11a ... Horizontal portion 11b ... Horizontal portion 11c ... Slope shaft portion A ... Bedrock B ... Buffer material C ... Waste

Claims (2)

A disposal tunnel facility that is constructed in the underground ground of a waste geological disposal site and consists of disposal tunnels in which waste is buried,
The disposal tunnel is inclined with respect to the horizontal, and an installation base having a horizontal installation surface is formed on the bottom plate of the inclination shaft with backfill material, and the waste is spaced on the installation base in the longitudinal direction of the inclination shaft. Disposal tunnel facility in a waste geological disposal site, which is arranged horizontally or substantially horizontally and backfilled with a backfill material. A disposal tunnel facility that is constructed in the underground ground of a waste geological disposal site and consists of disposal tunnels in which waste is buried,
The disposal tunnel is inclined with respect to the horizontal, and a step in the longitudinal direction of the shaft is formed on the bottom of the shaft, and an installation table with a horizontal installation surface is formed on the horizontal step of the stairs with backfill material. A disposal tunnel facility of a waste geological disposal site , wherein the waste is disposed on the installation table in a horizontal or substantially horizontal horizontal manner, and the space in the inclined shaft is backfilled with a backfilling material. .

Images