JPH11142593A - Radioactive waste storing container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable radioactive waste storing container which can resist to impacts and can maintain its soundness for a long period. SOLUTION: A radioactive waste storing container 10 is provided with an outer cylindrical body 11 having a closed bottom 11a and an opened top 11b and an inner cylindrical body 14 which is housed in the cylindrical body 11 and has an opened top 14b and a buffer structure 16 is provided in the bottom section 14a of the inner cylindrical body 14. When a radioactive waste 4 is housed in the container 10, the impact given by the waste 4 is absorbed by the structure 16 and the outer cylindrical body 11 is not deformed, but only the inner cylindrical body 14 is deformed. Therefore, the container 10 becomes highly reliable, because the container 10 can resist to the impact and can maintain its soundness for a long period. When a guide member 18 which is extended into the inner cylindrical body 14 is provided between the tops 11b and 14b of the cylindrical bodies 11 and 14, the radioactive waste 16 is guided onto the structure 16 in the bottom section 14a of the cylindrical body 14 by means of the guide member 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container for storing radioactive waste generated in, for example, a nuclear power plant of a light water reactor.

[0002]

2. Description of the Related Art An example of such a storage container according to the prior art is shown in FIG. The storage container 1 has a single structure,
The lid 3 is fastened to the top flange 2 by means such as bolts (not shown), and the internal radioactive waste 4
Is stored in a sealed state.

[0003]

With the single-layer structure as described above, when an impact force is applied to the storage container during storage of radioactive waste, the storage container is likely to be deformed or damaged, especially at the bottom thereof. If the storage container is stored for a long period of time, and if the storage container is damaged such as a leak or a crack due to the deformation or damage, there is a possibility that the radioactive substance leaks from the damage. Therefore, before reaching such a situation, it is necessary to replace the radioactive material in the storage container in which the above-mentioned damage is likely to occur with a new storage container,
The troublesome replacement work requires a considerable amount of time, in other words, human cost. This long replacement work is also a problem from the viewpoint of reducing radiation exposure of workers. Accordingly, an object of the present invention is to provide a highly reliable radioactive waste storage container that is strong against impact and can maintain soundness for a long period of time.

[0004]

For this purpose, a first aspect of the present invention is provided.
The radioactive waste storage container according to the present invention according to the present invention comprises an outer cylindrical body having a closed bottom and an open top, and an inner cylindrical body disposed in the outer cylindrical body and having an open top. A buffer structure is provided at the bottom. Claim 2
As described in the above, it is preferable that a guide member extending into the inner cylinder is provided between the tops of the outer cylinder and the inner cylinder.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. FIG.
1 shows a storage container 10 according to an embodiment of the present invention with a radioactive waste 4 stored therein. Storage container 10
Is provided with an outer cylindrical body 11 whose bottom 11a is closed and whose top 11b is open. A cover 13 is fixed to the cover 12 in a sealed state by an appropriate means such as a bolt (not shown).
The outer cylinder 11 is substantially cylindrical and has a bottom 11a.
Is formed from a flat plate.

[0006] Inside the outer cylinder 11, an inner cylinder 14 having a bottom portion 14a and a top portion 14b opened is housed.
On the bottom 11a of the outer cylinder 11, the bottom 1
4a is mounted, and the bottom plate 16 is mounted.
Strictly speaking, the bottom plate 16 has a hemispherical shape that is convex toward the inside as shown in FIG. 2 before the radioactive waste 4 is stored and before it is deformed by the impact of the radioactive waste 4. It is a buffer structure of a shape.

On the other hand, the top 14b of the inner cylinder 14 terminates below the top 11b of the outer cylinder 11. Provided in contact with the outer peripheral surface of the inner cylinder 14 is a protection member 15 that also serves as a guide when the inner cylinder 14 is inserted into the outer cylinder 11. Since this is not required to be strong, the bottom 14 of the inner cylinder 14 is
a and the top 14b may be terminated inward of the storage container 10 in the axial direction.

Further, a ring-shaped mounting plate 17 is integrally attached to the inner peripheral surface of the flange portion 12 of the outer cylindrical body 11 by an appropriate means such as welding. An irregularly shaped annular body (guide member) serving as a guide when the radioactive waste 4 is stored in the mounting plate 17 which can be considered
18 is attached by means such as bolts (not shown). The annular body 18 includes a large-diameter ring portion 18a attached to the mounting plate 17 as described above, an inclined ring portion 18b extending downward from the lower end thereof while being inclined inward in the radial direction, and a small-diameter ring hanging from the lower end. Part 18
c. The inclined ring portion 18b extends radially inward from the top of the inner cylinder 14, and the small-diameter ring portion 18c is located inside the cylinder 14. The annular body 18 not only functions as a guide for the radioactive waste 4 but also has a function of regulating the vertical movement of the inner cylindrical body 14.

An example of an assembling process of the radioactive waste storage container 10 according to one embodiment of the present invention having the above structure is as follows. 1) The inner cylinder 14 having the protection member 15 is connected to the outer cylinder 11
Insert inside. At this time, the protection member 15 serves as a guide. 2) The convex bottom plate 16 is placed on the bottom 11a of the outer tubular body 11. 3) Attach the annular body 18 to the flange 12 of the outer cylinder 11. 4) Put or store the radioactive waste 4 in the inner cylinder 14. At that time, the annular body 18 serves as a guide, and the radioactive waste 4 surely falls on the bottom plate 16. Since the bottom plate 16 has a hemispherical cushioning structure, deformation is unlikely to occur, and even if it occurs, it is only as shown in FIG. 1, thereby absorbing shock. Even if the inner cylindrical body 14 is deformed, the outer cylindrical body 11 is not deformed or damaged because the protection member 15 is attached to the outer periphery thereof. The annular body 18 prevents the inner cylindrical body 14 from moving up and down when the radioactive waste 4 is charged. 5) When a predetermined amount of radioactive waste 4 is stored, cover 13 is bolted (not shown) to flange 12 of outer cylinder 11.
And seal. Even if the inner cylinder 14 is damaged and leaks, there is no leakage to the outside of the outer cylinder 11.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications such as the following are possible. 1) The bottom plate 16 which is a buffer structure is a convex hemispherical shape in the embodiment, but any plate having a buffer function may be used.
Various shapes are possible. For example, it can be shaped like a saw,
It may be bamboo basket-shaped or frusto-conical. 2) The bottom plate 16 is shown as being separate from the other members in the embodiment, but the open bottom portion 14a of the inner cylindrical body 14 is provided.
May be formed integrally with the inner cylindrical body 14 as a member for closing. 3) In the embodiment, the annular body 18 has the large-diameter ring portion 1.
At 8a, it is attached to the attachment plate 17 on the outer cylinder 11 side. However, if the function of preventing the vertical movement of the inner cylindrical body 14 by the annular body 18 is not desired, the annular body 18 is
It may be attached to the top 14b of the inner cylinder 14 at c. 4) The mounting plate 17 is annular in the embodiment, but is not necessarily required, and a plurality of annular bodies 18 may be circumferentially separated only in the vicinity of a portion where the mounting plate 17 is bolted to the mounting plate 17. . Further, the annular body 18 is connected to the flange 12
The mounting plate 17 can be omitted if it is possible to directly attach the annular body 18 to the inner cylindrical body 14 as described above. 5) If the protective member 15 is formed in such a dimensional relationship as to come into contact with the inner peripheral surface of the outer cylindrical body 11 when the inner cylindrical body 14 is inserted into the outer cylindrical body 11, The protection member 15 can perform the movement preventing function.

[0011]

As described above, according to the first aspect of the present invention, the radioactive waste storage container is provided with an outer cylindrical body having a closed bottom and an open top, and disposed inside the outer cylindrical body. And an inner cylinder having an open top, and a buffer structure is provided at the bottom of the inner cylinder, so even if radioactive waste is stored, the shock is absorbed by the buffer structure, and Provides a highly reliable radioactive waste storage container that can withstand impact and maintain its soundness for a long period of time because it stays in the inner cylinder and does not reach the outer cylinder. Of the radioactive waste can be eliminated. Therefore, the radiation exposure of the worker due to the replacement of the radioactive waste can be reduced. Further, as described in claim 2, when a guide member that extends into the inner cylinder is provided between the tops of the outer cylinder and the inner cylinder, the radioactive waste is disposed in this manner. Since the guide member guides the bottom structure to the buffer structure, the above-described operation and effect of the first embodiment can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a storage container according to the present invention in which radioactive waste is stored.

FIG. 2 is a partial cross-sectional view showing a shape before deformation of a buffer structure in the storage container of FIG.

FIG. 3 is a sectional view showing a conventional storage container.

[Explanation of symbols]

4 ... radioactive waste, 10 ... radioactive waste storage container, 11
... Outer cylinder, 11a ... Bottom of outer cylinder, 11b ... Top of outer cylinder, 14 ... Inner cylinder, 14a ... Bottom of inner cylinder,
14b: the top of the inner cylinder, 16: bottom plate (buffer structure),
18 ... annular body (guide member).

Claims (2)

[Claims] An outer cylindrical body having a closed bottom and an open top;
A radioactive waste storage container, comprising: an inner cylinder having an open top provided in the outer cylinder; and a buffer structure provided at a bottom of the inner cylinder. 2. The radioactive waste storage container according to claim 1, wherein a guide member extending into the inner cylinder is provided between the tops of the outer cylinder and the inner cylinder.