JP3861391B2 - Method of geological disposal of buffer material for disposal of radioactive waste - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a geological disposal method for a cylindrical cushioning material provided around the radioactive waste so as to surround the radioactive waste when the high-level radioactive waste is disposed.
[0002]
[Prior art]
In general, high-level radioactive liquid waste from nuclear fuel reprocessing facilities is difficult to handle if it is in liquid form at the time of disposal, so it is planned to dispose deeply underground after stabilization treatment as a solidified glass. Has been.
[0003]
That is, this high-level radioactive liquid waste is first melted together with glass raw materials at a high-temperature disposal facility or the like and then placed in a stainless canister and stabilized as a glass solidified body. Next, since the canister containing this vitrified body generates high-temperature heat, it is transported to a vitrified body storage facility constructed on the ground, for example, and then naturally cooled for about 40 to 50 years. sealed housed overpack called thick sheet steel in the closed container, then the depth of the bedrock of the ground facilities f underground several hundred to one thousand and several hundred through the shafts c from m as shown in FIG. 5 It is transported to a disposal tunnel T built inside.
[0004]
Then, as shown in FIG. 6 , the radioactive waste a such as an overpack transported to the underground disposal tunnel T is then transported to the disposal tunnel T extending from the disposal site A, and then the disposal tunnel T Are accommodated one by one in a plurality of disposal holes b, b... Formed in the bottom of each, and then disposed in the disposal hole b for a long period of time.
[0005]
Further, as shown in the figure, when the radioactive waste a is accommodated in the disposal holes b, b..., A cylindrical cushioning material 1 formed by pressing bentonite powder or the like around the radioactive waste a is provided in advance. Thus, the influence of groundwater and bedrock pressure on the radioactive waste a is reduced.
[0006]
[Problems to be solved by the invention]
By the way, in the burying disposal method as described above, since a large number of disposal holes b, b... Must be excavated and formed at the bottom of the disposal tunnel T, the work period required for disposal is prolonged, and work efficiency for disposal is poor. Moreover, after the radioactive waste a is accommodated in each of the disposal holes b, b..., The disposal tunnel T becomes unnecessary and needs to be refilled each time, so the volume of the disposal tunnel T is wasted. There is a disadvantage that the disposal efficiency of the radioactive waste a is poor. Furthermore, since this cushioning material 1 is a heavy load of several tons to dozens of tons per unit, a large amount of labor is required for this transport operation and each disposal hole b.
[0007]
Therefore, the present invention has been devised to effectively solve such problems, and the purpose thereof is a novel radioactive waste disposal cushioning material that can greatly improve disposal efficiency and work efficiency. The geological disposal method is provided.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a first invention is a disposal method in which a cylindrical buffer material for containing radioactive waste is transported to an underground disposal site and then disposed in a geological formation. After excavating and forming a disposal tunnel extending in a substantially horizontal direction from the main tunnel, the buffer material in the disposal site is transferred to the disposal tunnel through the main tunnel while rolling the buffer material. It is arranged from the back to the vicinity of the entrance in a horizontally placed state, and then the disposal tunnel is backfilled for geological disposal.
[0009]
Thereby, it is not necessary to dig a disposal hole in the disposal tunnel as conventionally considered, and the amount of work when disposing the buffer material can be reduced. In addition, the cushioning material is disposed in the disposal tunnel as it is for disposal. Furthermore, since the cushioning material is conveyed while being rolled in a horizontal state, labor required for conveyance can be reduced.
[0010]
In addition, when the cushioning material is disposed of by the above-described method, the second invention eliminates a gap generated between the cushioning materials by interposing a candlestick-shaped spacer between the cushioning materials, so that the rock pressure applied to the cushioning material is eliminated. Can be made even.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, a preferred embodiment for carrying out the present invention will be described with reference to the accompanying drawings.
[0014]
FIG. 1 is a plan view showing a part of an underground disposal facility according to the first invention method, in which A is a disposal site constructed several hundred m to several hundreds of meters underground, and R is a disposal site A The main tunnels extending in the horizontal direction, T, T... Are bag-shaped disposal tunnels excavated from the main tunnel R in a substantially horizontal direction, and FIGS. 2 and 3 are sectional views showing the disposal tunnels T, respectively.
[0015]
As shown in the figure, in the disposal method of the present invention, the cylindrical cushioning material 1 and the substantially candlestick-shaped spacer 2 in the disposal site A are alternately passed through the main tunnel R by the dedicated transport carriages 3 and 4, respectively. They are transported to the disposal tunnel T, and arranged from the back of the disposal tunnel T to the vicinity of the entrance alternately in a horizontal state.
[0016]
At this time, as shown in FIG. 1 and FIGS. 3A and 3B, the cushioning material 1 has a cylindrical shape, so that the floor surface from the disposal site A to the disposal tunnel T is substantially horizontal and flush. In this state, the carrier cart 3 pushes one side of the cushioning material 1 and rolls it to a predetermined position while rolling, so that the carrying work can be easily performed.
[0017]
On the other hand, since the spacer 2 having a generally candlestick-like cross section cannot be conveyed while being rolled like the cushioning material 1, for example, as shown in FIGS. 2 (A) and 2 (B), on the side surface of the spacer body 2a. Several insertion holes 2b are formed, and it can be conveyed to a predetermined position by traveling while lifting the spacer 2 by a forklift type conveyance carriage 4 having a lifting member 4a inserted into the insertion hole 2b. In addition, in the buffer material 1, the radioactive waste a such as the overpack described above is accommodated in the disposal site A in advance.
[0018]
And while forming the cross-sectional shape of this disposal tunnel T in the shape similar to the longitudinal cross-sectional shape of the buffer material 1, the cross-sectional area of the disposal tunnel T is set slightly larger than the vertical cross section of the buffer material 1, and a disposal tunnel By accommodating the buffer material 1 from the back of T so as to be sequentially arranged in parallel, the disposal tunnel T is filled with the buffer material 1. Moreover, since the outer shape of the cushioning material 1 is formed in a columnar shape as described above, a void having a substantially triangular cross section is generated between the buffer material 1 and the disposal tunnel T, and the rock pressure is increased. Although there is a possibility that the cushioning material 1 is not evenly applied to each cushioning material 1, as described above, by providing the candlestick-like spacer 2 between the cushioning materials 1, the gaps are closed and the voids are eliminated. The rock pressure applied to the rock can be made even. For the convenience of conveyance, a certain amount of gap is generated around the cushioning material 1 and the spacer 2. In this gap, a powder fluid such as bentonite powder, concrete or earth and sand is used for this gap. The inside of the disposal tunnel T can be almost completely backfilled by pouring and filling. For example, bentonite powder of the same material as the buffer material 1, concrete, earth and sand, etc. are formed in the gap formed around the buffer material 1 (upper and side portions of the buffer material 1) by the powder fluid supply device F shown in FIG. 4. It will be poured and the gap will be filled to refill the disposal tunnel T.
[0019]
As described above, the method according to the present invention uses the disposal tunnel T, which is a conveyance passage for the buffer material 1, as it is as a disposal hole for disposing the buffer material 1, and therefore, the buffer method is buffered as compared with a conventionally considered disposal method. The conveyance efficiency and disposal efficiency of the material 1 can be greatly improved. Moreover, since the disposal hole as described above is not required, excavation work of the disposal hole becomes unnecessary, and the construction period of the disposal facility can be shortened and the disposal cost can be reduced at the same time. In addition, since the cushioning material 1 is a heavy material of several tons to several tens of tons, if an inclined surface is formed so as to gradually fall from the disposal site A to the tip of the disposal tunnel T, the cushioning material at the time of transportation is used. The rolling resistance of 1 is also reduced, and the carrying work is further facilitated.
[0026]
The spacer 2 for use in the present invention process, rather than integrally formed, may be formed in a block body which is divided in advance into a plurality.
[0027]
【The invention's effect】
In short, according to the present invention, since the disposal tunnel which is the buffer material transport passage is used as it is as a disposal hole for disposal of the buffer material, the transport of the buffer material compared with the conventionally considered disposal method Efficiency and disposal efficiency can be greatly improved. In addition, since the disposal hole as described above is not required, excavation work of the disposal hole becomes unnecessary, and it is possible to exert excellent effects such as shortening the construction period of the disposal facility and simultaneously reducing the disposal cost. it can.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a method of the present invention.
FIG . 2 (A) is a longitudinal sectional view showing the vicinity of the tip of the disposal mine according to the method of the present invention , and FIG. 2 (B) is a plan view showing the vicinity of the tip of the disposal mine according to the method of the present invention.
FIG . 3 (A) is a longitudinal sectional view showing the vicinity of the tip of the disposal mine according to the method of the present invention , and FIG. 3 (B) is a plan view showing the vicinity of the tip of the disposal mine according to the method of the present invention.
FIG. 4 is a side view showing a state in which powder fluid is filled in a gap between cushioning materials arranged in the disposal tunnel.
FIG. 5 is a schematic diagram showing a configuration of a disposal facility when geological disposal of radioactive waste is performed.
FIG. 6 is an explanatory view showing a radioactive waste disposal method conventionally considered.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Buffer material 2 Spacer 3, 4 Carriage cart 5 Block body A Disposal site R Main tunnel T Disposal tunnel a Radioactive waste

Claims (2)

  In a disposal method in which a cylindrical buffer material for transporting radioactive waste is transported to an underground disposal site and then disposed of in geological formation, a disposal tunnel extending substantially horizontally from the main tunnel of the disposal site is provided. After excavating and transporting the buffer material in the disposal site to the disposal tunnel through the main tunnel, the buffer material is arranged from the depth of the disposal tunnel to the vicinity of the entrance in a horizontal state, and then The geological disposal method of the radioactive waste disposal buffer material, wherein the disposal tunnel is backfilled and the geological disposal is performed.   The method for forming a radioactive waste disposal buffer material according to claim 1, wherein a spacer is provided between the cushioning materials.

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