JPH10319190A - Method of manufacturing cushioning material lining for radioactive waste storage container - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A radioactive waste having a novel structure in which a disposal container can be easily and stably covered with a buffer material without laying or stacking a large number of buffer material blocks. Realize a storage container. SOLUTION: A concave portion is formed on the upper surface of the packed layer of the raw material powder of the buffer material filled in the container main body 1, and the upper portion of the container main body 1 is formed by a stretchable liquid-tight diaphragm having a tuft portion that enters the concave portion. It is closed, put in a pressure vessel, and fluid pressure is applied isotropically to compress and form the cushioning material lining base body integrated with the vessel body 1 by the packed layer, and the flat upper surface 10a and the storage space 5 by cutting. Forming a cushioning lining 10
And Then, the disposal container 4 containing the radioactive waste is inserted into the storage space 5, the storage space 5 is closed by the buffer material block 11, the upper surface thereof is covered by the upper lid 7, and the storage container 9 is sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cushioning material lining for a radioactive waste storage container.

[0002]

2. Description of the Related Art In recent years, radioactive waste liquid generated in a nuclear reactor such as a power plant is mixed into molten glass, and the molten glass mixed with the radioactive waste liquid is filled in a canister (metal container) to solidify the glass. To form a vitrified material, and the vitrified material is to be stored in a radioactive waste storage facility until the decay heat is removed, and at present, after the decay heat is removed It is being studied to perform geological disposal by burying the vitrified material in rocks underground several hundred meters below ground.

In the case where the vitrified material is buried in the underground rock for geological disposal, the vitrified material is stored in a disposal container, and a number of disposal holes are dug down in the bottom of a disposal tunnel formed deep underground. It is conceptually considered that a disposal container is inserted into the disposal hole, and the entire surface of the disposal container is buried in the disposal hole by enclosing it with a buffer material such as bentonite. When wrapping with a material, in order to save the labor in the disposal tunnel, the disposal container is previously wrapped with a buffer material on the ground and stored in a metal storage container. There is a plan to bring it to a disposal tunnel and bury it in a disposal hole.

FIG. 4 shows a conventional storage container for accommodating a disposal container together with a cushioning material. In FIG. 4, reference numeral 1 denotes a metal container main body formed in a box shape having an upper opening. A relatively large buffer material block 2 made of bentonite or the like is laid on the bottom of the container and a relatively small buffer material block 3 is stacked along the inner surface of the container body 1 to insert the disposal container 4. Define storage space 5,
After inserting the disposal container 4 into the storage space 5, a relatively large buffer block 6 is spread over the upper part in the container body 1 to close the storage space 5, and finally the upper opening of the container body 1 is opened. Is closed by joining a metal upper lid 7 so that the storage of the disposal container 4 can be completed.

[0005]

However, in the conventional structure as described above, a large number of cushioning material blocks 2, 3, 6 are required.
It takes a great deal of time to lay or pile up piles, and high technology is required to perform these operations with high accuracy. In addition, the cushioning material blocks 2, 3, and 6, which are brittle materials during the operation, are required. There was a problem that it was easily damaged.

Further, when stacking the cushioning material blocks 2, 3, and 6, it is inevitable that a gap is formed in a portion adjacent to the inner side surface of the container body 1, and the gap may cause variations in cushioning material performance. In addition, in order to prevent rattling due to the gap at the time of transportation, a processing is performed so that the mutual joining surfaces of the cushioning material blocks 2, 3, and 6 can be cut and closely matched. It is necessary to fill the gap 8 formed in the portion adjacent to the inner surface of the container body 1 with the powder 8 of the cushioning material.

Further, if the gaps are filled with the cushioning material powders 8 only by laying or stacking the cushioning material blocks 2, 3, and 6, for example, when the container body 1 is placed on its side, the inside of the container body 1 is removed. As a result, the shock absorbing material blocks 2, 3, and 6 may move, or the shock absorbing material powder 8 may shift, and the storage state may change, and the shock absorbing material performance expected at the beginning may not be maintained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and is intended to easily and stably cover a disposal container with a cushioning material without laying or stacking a large number of cushioning material blocks. It aims to realize a radioactive waste storage container with a new structure.

[0009]

According to the present invention, there is provided a container body having an opening at an upper portion, and a container body provided integrally inside the container body and having a lower position than an upper end of the container body as an upper surface, and substantially at the center of the upper surface. A cushioning material lining forming a storage space extending downward, a single cushioning material block installed on the upper surface of the cushioning material lining to close the storage space, and a top surface of the container body covering the upper surface of the cushioning material block A method for producing a buffer material lining of a radioactive waste storage container having an upper lid joined to an upper end thereof, wherein the raw material powder of the buffer material is filled in the container body, and from a substantially central position on the upper surface of the packed layer of the raw material powder. Forming a recess extending downward, closing the upper part of the container body with a stretchable liquid-tight diaphragm formed along the surface shape of the filling layer with a tuft entering the recess, Container book Into a pressure vessel, pressurize fluid pressure isotropically, compression-mold the cushioning material lining foundation integrated with the vessel body by the packed layer, and then remove the diaphragm to form the cushioning lining foundation. The upper layer around the recess is cut to form a flat upper surface at a position lower than the upper end of the container body, and the inner surface of the recess is cut to substantially match the outer shape of the disposal container storing the radioactive waste. To form a storage space.

[0010] Thus, the buffer lining integrated with the container main body can be easily formed inside the container main body, so that the storage space formed in the buffer lining can be accommodated in the storage space. After inserting the disposal container, a buffer material block is installed on the upper surface of the buffer material lining to close the storage space, and the upper surface of the buffer material block is covered with the upper lid of the container body, and the edge of the upper lid is covered with the container. By joining to the upper end of the main body, it is possible to easily and stably store the disposal container in the storage container without laying up or stacking a large number of buffer material blocks. Become.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention, in which the same reference numerals as those in FIG. 4 denote the same parts.

In the figure, reference numeral 9 denotes a storage container for storing the disposal container 4 on the ground in a state of being previously wrapped with a cushioning material. The storage container 9 includes a container body 1 having an open upper part,
The container body 1 is provided integrally inside the container body 1 and
The cushioning material lining 10 having a storage space 5 extending downward at substantially the center of the upper surface 10a with the lower position than the upper end of the cushioning material as the upper surface 10a; And a top cover 7 that covers the upper surface of the buffer material block 11 and is joined to the upper end of the container body 1.

Here, in manufacturing the cushioning material lining 10 of the storage container 9, as shown in FIG. 2, a raw material powder 10 'of the cushioning material is filled in the container body 1, and the filling of the raw material powder 10' is performed. A concave portion 13 extending downward from a substantially central position on the upper surface of the layer 12 is formed, and a stretchable liquid-tightness formed along the surface layer shape of the filling layer 12 with a tuft portion 14 penetrating into the concave portion 13 is formed. The upper part of the container body 1 is closed by a diaphragm 15, and the container body 1 is
The filling layer 12 is compression-molded as a cushioning material lining base body 10x integrated with the container body 1 by applying fluid pressure isotropically by a cold isostatic pressing press (CIP molding method).

At this time, the fluid pressure acts outward from the concave portion 13 side toward the container body 1 through the tuft portion 14 of the diaphragm 15, so that the inner layer and the bottom surface of the container body 1
2 is compressed well, and the cushioning lining base body 10x without gaps, which is tightly integrated with the inside of the container body 1, is compression molded.

It is preferable that the container body 1 is set to have a sufficient design strength in advance so as not to be deformed by a fluid pressure acting from the inside. The cold isostatic pressing may be performed by inserting the sleeve into the sleeve.

Next, after the diaphragm 15 is removed, as shown in FIG. 3, a processing machine 17 cuts an upper layer portion around the recess 13 of the cushioning material lining base body 10x as shown by a two-dot chain line in FIG. To form a flat upper surface 10 a at a position lower than the upper end of the container body 1, and cut the inner surface of the recess 13 so as to substantially conform to the outer shape of the disposal container 4 storing the radioactive waste. To form

In this way, the cushioning lining 10 integrated with the container body 1 is provided inside the container body 1.
The disposal container 4 is inserted into the storage space 5 formed in the cushioning material lining 10, and then the cushioning material block 11 is installed on the upper surface 10a of the cushioning material lining 10. If the storage space 5 is closed and the upper surface of the cushioning material block 11 is covered with the upper lid 7 of the container body 1 and the edge of the upper lid 7 is joined to the upper end of the container body 1,
The disposal container 4 can be simply and stably stored in the storage container 9 in a state of being wrapped with the buffer material without laying or stacking a large number of buffer material blocks.

Therefore, according to the above embodiment, the work of laying and stacking a large number of cushioning material blocks is not required, so that the labor involved in these works can be greatly reduced and the disposal container 4 can be stored. There is no longer any need for extraordinary technology for storing in the container 9,
Moreover, the buffer material that needs to be directly handled during the storage operation of the storage container 9 is only the buffer material block 11,
The possibility of damaging the cushioning material is extremely reduced.

Further, since the gap which has conventionally been formed in the portion adjacent to the inner surface of the container body 1 when the cushioning material blocks are stacked is eliminated, the performance of the cushioning material may vary due to the existence of such a gap. Is lost, and
In order to prevent rattling due to the gap at the time of transport, the cushioning material is cut and processed, or a gap generated in a portion adjacent to the inner surface of the container body 1 is filled with the buffer material powder. Since no work is required, the labor required for these works can be saved.

In addition, for example, even in the case of a horizontal posture, the buffering material moves in the container body 1 or the powder of the buffering material filled in the gap shifts to change the storage state. Since such a trouble does not occur, the cushioning material performance expected at the beginning can be reliably maintained, and the constraint on the posture of the storage container 9 at the time of transport can be relaxed, and the transport operation can be facilitated. The reliability of cushioning material performance after burying in underground rock and performing geological disposal can be greatly improved.

It should be noted that the method of manufacturing the cushioning material lining of the radioactive waste storage container of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention. Of course.

[0023]

According to the above-mentioned method of manufacturing a buffer lining for a radioactive waste storage container of the present invention, various excellent effects as described below can be obtained.

(I) Since the buffer material lining integrated with the container body can be easily formed inside the container body, the disposal container is inserted into the storage space formed in the buffer material lining, and thereafter, By installing a cushioning material block on the upper surface of the cushioning material lining to close the storage space, covering the upper surface of the cushioning material block with the upper lid of the container body and joining the edge of the upper lid to the upper end of the container body, Disposal containers can be easily and stably wrapped in cushioning material without being laid or piled up, and a large number of cushioning material blocks are conventionally laid. And the labor required for the work of stacking and stacking can be greatly reduced, and extraordinary technology is required to store the disposal container in the storage container. No longer, moreover, cushioning material that must be handled directly in the housing during operation of the container is to become the only buffer material block, fear becomes extremely small that cushioning material is damaged.

(II) Since the gap which has conventionally been formed in the portion adjacent to the inner side surface of the container body when the cushioning material blocks are stacked is eliminated, the performance of the cushioning material may be varied due to the existence of such a gap. Is lost, and
Work to cut and process the buffer material to prevent rattling due to the gap during transport, or to fill the gap generated in the portion adjacent to the inner surface of the container body with the powder of the buffer material Is unnecessary, so that the labor required for these operations can be saved.

(III) For example, even in the case of a horizontal posture, the storage state changes due to the movement of the cushioning material in the container body or the deviation of the cushioning material powder filled in the gap. As a result, the cushioning material performance expected at the beginning can be reliably maintained, the constraints on the posture of the storage container at the time of transport can be eased, and the transport operation can be facilitated. The reliability of the cushioning material performance after burying it in the bedrock and disposing it in the geological formation can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state where the cushioning material lining base body of FIG. 1 is being compression molded.

FIG. 3 is a cross-sectional view showing a state in which a cutting process is performed on the cushioning material lining base body of FIG. 2;

FIG. 4 is a sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container main body 4 Disposal container 5 Storage space 7 Top lid 9 Storage container 10 Buffer material lining 10 'Raw material powder 10a Upper surface 10x Buffer material lining base body 11 Buffer material block 12 Filling layer 13 Depression 14 Tubular part 15 Diaphragm 16 Pressure vessel

Claims (1)

[Claims] 1. A container main body having an open upper part, and a storage space integrally provided inside the container main body and extending downward at a substantially central position of the upper surface with a position lower than the upper end of the container main body as an upper surface. A cushioning material lining, a single cushioning material block installed on the upper surface of the cushioning material lining and closing the storage space, and an upper lid covering the upper surface of the cushioning material block and joined to the upper end of the container body. A method for producing a buffer material lining of a radioactive waste storage container, comprising: filling a raw material powder of a buffer material in a container body; and forming a concave portion extending downward from a substantially central position on an upper surface of a packed layer of the raw material powder. Closing the upper part of the container body with a stretchable liquid-tight diaphragm formed along the surface shape of the packed layer with a tuft part that enters the concave part, and puts the container body in a pressure vessel. Fluid Pressure isotropically applied to compress the cushioning lining foundation integrated with the container body by the filling layer, and then, after removing the diaphragm, cut the upper layer around the recess of the cushioning lining foundation. Forming a flat upper surface at a position lower than the upper end of the container body, and forming a storage space by cutting the inner surface of the concave portion so as to substantially match the outer shape of the disposal container storing the radioactive waste. A method for producing a cushioning material lining of a radioactive waste storage container.