JP2000275397A - Concrete cask storage device for vitrified material - Google Patents

Abstract

(57) [Problem] An object of the present invention is to provide a novel concrete cask storage device for vitrified material, which can economically store a relatively small amount of vitrified material. SOLUTION: A plurality of storage tubes 21 are accommodated in a transportable concrete cask 20 at a fixed interval from each other so as to store a plurality of vitrified bodies 6 in a vertically stacked manner, respectively. By forming an intake port 22 for taking in cooling air at the lower part of 20, and having an exhaust port 23 for exhausting heated air after cooling on the upper part, a relatively small amount of the vitrified body 6 can be efficiently cooled. Even the vitrified body 6 can be stored economically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete cask storage device for a vitrified body for cooling and storing a vitrified body such as a high-level radioactive liquid waste.

[0002]

2. Description of the Related Art A high-level radioactive waste liquid from a nuclear fuel reprocessing facility or the like is put into a glass melting furnace together with a glass raw material because it is inconvenient to handle it as a liquid.
After being melted at a high temperature of about 1200 ° C. to 1200 ° C., they are sealed in a cylindrical stainless steel container (canister), processed in a stable form as a vitrified body, and then buried deep underground. ing. However, since this vitrified body generates high heat (decay heat),
Prior to geological disposal, it is stored for about 40 to 50 years in a concrete vitrified storage facility called a bold type, which is provided outdoors or the like as shown in FIG. 3, and is naturally cooled. I have.

[0003] As shown in the figure, the vitrified storage facility has a storage room 2 for storing the solidified package 6 formed in a storage building 1 made of strong thick concrete. Then, as shown by the arrow in the figure, the storage building 1
The cooling air (outside air) taken in from the cooling air inlet 3 formed at one end of the storage building 1 passes through the storage room 2 and is discharged into the atmosphere from the cooling air outlet 4 formed at the other end of the storage building 1. The solidified package 6 in the storage room 2 is cooled by air.

[0004] That is, as shown in FIG. 4, the storage room 2 is provided with a cylindrical storage tube 8 for housing a plurality of the solidified packages 6 on a ceiling slab 7 made of steel concrete which vertically partitions the inside of the storage building 1. A plurality of support frame plates 11 are arranged vertically through the plurality of support frame plates 11, each of which has a cylindrical ventilation pipe 10, which is vertically open around the storage pipe 8, and which is positioned in parallel with the ceiling slab 7. 11 are provided so as to be supported.

[0005] A plurality of solidified packages 6 (generally, about nine for one storage tube 8) are vertically stacked on each storage tube 8 by a solidified package transport crane (not shown) provided above the ceiling slab 7. Then, the upper opening of the storage tube 8 is closed with a storage tube plug 12 to shield radiation from the solidified package 6 side, and the upper portion of the storage tube plug 12 is stored in a disk shape. After covering the inside of the storage tube 8 by covering it with the tube lid 13, cooling air is caused to flow upward along the periphery of the storage tube 8 from the lower opening of each ventilation tube 10 as shown by the dashed arrow in the figure. The heat generated from the storage tube 8 is taken away to efficiently cool the air.

[0006]

However, in such a bold-type vitrified storage facility, when a large amount (1000 to 2000 or more) of vitrified materials are collectively stored, it is comparatively difficult. Although it has economic merit, when storing a small amount of vitrified material, for example, about ten to several tens of vitrified materials, the construction cost increases, and the economical efficiency is deteriorated. .

On the other hand, about ten and several vitrified bodies are housed in a cylindrical metal container made of a thick steel plate having a thickness of about several tens cm, and the vitrified body is generated by the metal container. There has been proposed a storage device called a metal cask system in which radiation and decay heat are stored while being shielded.

However, this metal cask type storage device is suitable for storing a small amount of vitrified material, but requires a large amount of metal material (steel material), so that the metal container itself is very expensive. There is a disadvantage that there is.

Accordingly, the present invention has been devised to effectively solve such problems, and an object of the present invention is to provide a novel glass capable of economically storing a relatively small amount of vitrified material. An object of the present invention is to provide a concrete cask storage device for a solidified body.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a concrete cask that can be transported.
A plurality of storage tubes are housed at a constant interval from each other in order to store a plurality of vitrified bodies in a vertically stacked manner, and a cooling air intake port is formed at a lower portion of the concrete cask, and an upper portion thereof is formed. It is equipped with an exhaust port for exhausting heated air after cooling, the storage tube used in the conventional bold type storage equipment, and a mode of a metal cask type storage device are adopted, respectively. It is located in the middle of these storage devices.

That is, in the concrete cask storage device for vitrified material of the present invention, by adopting such a configuration, the site and waste like a bold type storage facility are eliminated, and a metal cask type storage device is used. Since almost no expensive metal material such as a storage device is used, when a relatively small amount of vitrified material is stored, it can be economically stored.

Further, since the exhaust port and the intake port are formed on the upper and lower sides of the concrete cask, respectively, the vitrified body housed by utilizing the natural flow of the air itself can be efficiently used similarly to the bold type storage facility. Can be stored while cooling.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of a concrete cask storage device (hereinafter, abbreviated as storage device) for vitrified material according to the present invention, and FIGS. 2 (A) and 2 (B) are diagrams respectively. 1 is an XX sectional view and a YY sectional view in FIG.

As shown in the figure, this storage device includes a plurality of storage tubes 21 (in this embodiment, seven storage tubes 21) for storing a plurality of vitrified bodies 6 in a drum-shaped cask 20 in a plurality of upper and lower stages. Book) A plurality of intake ports 22 for introducing cooling air (outside air) and a plurality of exhaust ports 23 for exhausting internal heating air are provided at a lower portion and an upper portion of the cask 20 at predetermined intervals. It has a formed structure.

The cask 20 is made of reinforced concrete, and its size is not particularly limited. For example, the cask 20 has a diameter of about 5 m, a height of about 7 m,
The thickness of the side wall is about 1.5 m.

The storage tube 21 is a tubular storage container made of a metal material having excellent thermal conductivity, such as a steel tube or a stainless steel tube, and its upper end portion penetrates through the ceiling wall 24 of the cask 20. It is supported so that it can be hung. Further, a shielding plug 25 made of concrete is fitted into the upper end opening of each of the storage tubes 21 to shield radiation and heat from the upper opening side. Further, a disc-shaped sealing lid 26 is provided on the upper part of the shielding plug 25 to shield radiation and heat from the upper opening side of the storage tube 21 together with the shielding plug 25. It is designed to surely prevent falling off. Since the length of the vitrified body 6 housed in the storage tube 21 in the upper and lower tiers is generally about 1 m per one tube, one storage tube 2 is used.
Approximately four to five wires are accommodated for one.
The upper and lower thicknesses of the cask 20 are slightly smaller than the side walls because the radiation dose is relatively small compared to the side walls.

The intake port 22 and the exhaust port 23 are formed so as to be located on four sides from the center of the cask 20, respectively. Further, a shielding plate having a radiation shielding function (such as a lead plate) is provided in the opening. ) Are provided at the top and bottom at appropriate intervals.

Therefore, in the storage device of the present invention having such a structure, as shown in FIG. 1, the shielding plug 25 of each storage tube 21 is removed in a closed room in a radioactive waste treatment facility. After about 4 to 5 vitrified bodies 6 are accommodated in the storage tube 21 in upper and lower stages, the storage tube 2
By closing the shielding plug 25 by fitting it into the upper opening of the first and welding the sealing lid 26 to the upper part, the radiation of the vitrified body 6 can be housed therein while completely shielding the radiation.

Further, as shown in the drawing, by storing in such a state, ascending heat generated from the vitrified body 6 in the cask 20 generates an upward flow in the air in the cask 20 as shown by the arrow in the drawing. Then, along with this, after the outside air is sucked into the cask 20 from the intake port 22 as the cooling air, it is heated inside the cask 20 and rises inside the cask 20 to reach below the ceiling wall 24, and from there. The air flows to the exhaust port 23 side and is naturally exhausted to the outside of the cask 20.

As a result, the rise in temperature inside the cask 20 is suppressed, and at the same time, all the vitrified bodies 6 are effectively cooled through the respective storage tubes 21.

In the storage device of the present invention, a relatively small amount of about ten to several tens of vitrified bodies 6 can be collectively stored. Such waste does not occur, and excellent economic efficiency can be exhibited. In addition, since most of the cask 20 is made of relatively inexpensive concrete, the manufacturing cost can be reduced as compared with the expensive metal cask system, and the concrete thickness of the cask 20 is sufficiently ensured. By doing so, it is possible to exhibit an excellent radiation shielding ability equal to or higher than that of the metal cask method.

Further, the storage device of the present invention can be transported to any storage place unlike a fixed type storage device such as a bold type storage facility, and is lighter in weight than a metal cask. The transfer operation can be performed relatively easily.

Incidentally, since the decay heat from the vitrified body 6 may reach a considerably high temperature (over one hundred and several tens of degrees Celsius), a metal liner for heat insulation is provided on the inner wall and upper and lower walls of the cask 20. It may be provided to reduce the thermal effect on the concrete base material. Further, since the vitrified body 6 becomes considerably heavy, an appropriate number of support beams 28 may be provided in the cask 20 and the storage tube 21 may be supported by the support beams 28 together with the ceiling wall. Further, similarly to the conventional bold type storage facility, a ventilation pipe 10 having a larger diameter may be provided around each storage pipe 21.

[0025]

In summary, according to the present invention, the following excellent effects can be exhibited.

In the concrete cask storage device for vitrified material according to the present invention, the site and waste as in a bold type storage facility are eliminated, and expensive metal materials such as a metal cask type storage device are almost completely eliminated. Since they are not used, when storing a relatively small amount of vitrified materials, they can be stored economically.

Further, since most of the concrete cask according to the apparatus of the present invention is made of relatively inexpensive concrete, the manufacturing cost can be reduced as compared with the expensive metal cask system.

Further, by securing a sufficient thickness of the concrete of the concrete cask, it is possible to exhibit an excellent radiation shielding ability equal to or more than that of the metal cask system.

Furthermore, by forming an exhaust port and an intake port on the upper and lower sides of the concrete cask, respectively,
Like the bold type storage facility, the stored vitrified material can be efficiently cooled by utilizing the natural flow of the air itself.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view showing an embodiment of the present invention.

FIG. 2A is a sectional view taken along line XX in FIG. FIG. 2B is a sectional view taken along line YY in FIG.

FIG. 3 is a configuration diagram illustrating an example of a conventional bold-type vitrified solid storage facility.

FIG. 4 is a partial view showing the vicinity of a storage pipe of a conventional bold type vitrified waste storage facility.

[Explanation of symbols]

 6 Vitrified body 20 Concrete cask 21 Storage pipe 22 Intake port 23 Exhaust port 24 Ceiling wall 25 Shielding plug 26 Sealing lid 27 Shielding louver

Claims (4)

[Claims] 1. A plurality of storage pipes are housed at regular intervals in a transportable concrete cask so that a plurality of vitrified bodies are stacked and housed in a plurality of upper and lower stages, respectively. A concrete cask storage device for vitrified material, comprising: an intake port for taking in cooling air therein; and an exhaust port for exhausting the heated air after cooling at an upper portion thereof. 2. The glass according to claim 1, wherein each of the storage tubes penetrates a ceiling wall of the concrete cask, and an upper end thereof is supported so as to be suspended from the ceiling wall. Concrete cask storage device for solidified material. 3. A louver for shielding radiation at each of the intake port and the exhaust port.
4. A concrete cask storage device for a vitrified product according to claim 1. 4. The concrete cask storage device for a vitrified product according to claim 1, wherein the thickness of the side wall of the concrete container is at least 1500 mm or more.