JPS6331759B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for packaging radioactive waste, particularly non-flammable miscellaneous solid waste, from nuclear power plants or other facilities handling radioactive materials.

In the case of such radioactive waste, the radiation emitted from it has a tremendous impact on living things in the natural world, including humans, so until it is finally disposed of (for example, dumped in the ocean or buried underground), You are required to keep this.
In this case, since the above-mentioned waste is generally extremely bulky, there is a problem in that a very large storage space is required if it is stored as is. Therefore, in order to eliminate this problem, the above waste is once melted in a crucible of a high frequency induction furnace or an arc furnace.
A method was also considered in which the molten material was poured into a solidification container by tilting the furnace body and solidified, and the solidified material was then transferred to a storage container and stored, but this method required a lot of time and effort during the process. There is a problem that it takes a lot of time.

The present invention is designed to eliminate the above problems,
It is an object of the present invention to provide a radioactive waste container filling device that can reduce the volume of the waste and also reduce the amount of work required.

Before describing the embodiments of the present application, a method for packaging small-sized radioactive solid waste or radioactive solid waste made into small-sized containers will be described below.

In FIG. 1, numeral 1 indicates non-flammable radioactive solid waste, ranging from large-sized waste 1a to small-sized waste 1b placed in a container 2, as shown. Such waste 1 includes metals (pipes, valves, plates, molded steel, tools, etc.), waste filters (prefilters, HEPA filters), and inorganic materials (insulating materials, fireproof materials, glass, concrete, etc.)
There is. As is well known, and as shown in FIG. 2A, such radioactive waste 1 contains radionuclides 4 on the surface of solid objects 1' forming pipes, filters, glass, etc. as described above. is contaminated with radioactivity.

The waste 1 is then melted in a melting furnace 5.
Prior to this melting step, the large waste 1a is broken down into smaller pieces by a size reduction device 3 such as a plasma cutter, hacksaw, or press.

Further, the container 6 is prepared prior to the melting process.
As this container 6, a container that can be used as is for storage as described later, that is, a container that is suitable for use as is for storage in terms of its structure, size, cost, durability, etc. is used. As an example, a canister 7 made of metal (for example, iron) is provided with a crucible 8 made of refractory material (for example, graphite). This container 6 is placed on the transfer device 10 by a transfer device such as a crane 9. The transfer device 10 includes a moving truck 11, a cylinder 12 fixed to the truck 11, a lower cover 13 attached to an advance/retractor 12a of the cylinder 12, and a pedestal 14. When the container 6 is placed on the pedestal 14 by the crane 9, the transfer device 10 is moved below the furnace body 15 in the melting furnace 5. and cylinder 12
is extended, the lower lid 13 closes the lower opening of the furnace body 15, and the container 6 is positioned at a predetermined position within the furnace body 15.

The melting furnace 5 includes a plasma torch 17 and a lifting device 18 for lifting and lowering the plasma torch 17.
, a waste carrying device 19 and a cooling device 2 for the container 6
has 0. The carrying-in device 19 includes a rail 21 installed within the furnace body 15, a bucket 22 movable along the rail 21, and a cylinder 23 for moving the bucket 22. In addition, 24 indicates a valve,
It is opened when the bucket 22 is moved.

The radioactive waste 1 is placed on a bucket 22 and carried into the furnace body 15, and when the bottom plate of the bucket 22 is opened, it is thrown into the container 6 at a predetermined position. In this case, the plasma torch 17 is lifted up by the lifting device 18.

After the waste 1 has been thrown in as described above, the bucket 22 is pulled out of the furnace and the plasma torch 17 is lowered. The container 6 is then exposed to the high temperature plasma arc emitted from the plasma torch 17.
The waste 1 inside is heated. This results in waste 1
melts. When the waste material 1 is melted in this way, its bulk becomes smaller, so the waste material 1 is again thrown in and the melting operation is performed in the same manner as described above.

During the above-mentioned work, cooling air is blown out from the cooling device 20 toward the outer wall of the container 6.
Protect container 6 from overheating.

When the container 6 becomes full after repeating the above operation several times, the container 6 is transferred to the moving device 10.
is carried out from the furnace 5 by. Note that the waste 1c in the container 6 (the state is different from that before melting, so the reference numeral will be changed in the explanation) is solidified before or during its removal.

Next, the container 6 that has been carried out is covered with a lid 25. This lid 25 is welded to the container 6 by a welding device 26, and the inside of the container 6 is sealed.

The container 6 sealed in this way is then stored in the storage 2.
7, where it will be stored until it is dumped into the ocean or otherwise disposed of.

The radioactive waste 1c packed in the container 6 as described above has undergone the melting operation as described above, so before melting, the solid material 1c is as shown in FIG. 2A. The radioactive nuclide 4 that had adhered to the surface of the solid object 1'c was buried in the molten material, and when it solidified again, the nuclide 4 was incorporated into the solid material 1'c that had once been melted and solidified. It is becoming. Therefore, part of the radiation emitted from nuclide 4 is blocked by solid object 1'c, so
The amount of radiation coming out of the container 6 is small.

Next, FIG. 3 shows a different embodiment of the container. This container 6e is a canister 7e and a crucible 8e.
Concrete 28 is filled between the two. The lid 29 is constructed by covering the inner surface of a metal outer plate with concrete. The thickness of these concretes is the thickness required for final disposal (dumping into the ocean) as described above.

When the container 6e configured in this manner is used, it becomes possible to immediately transfer the container to final disposal after storage as described above. In this example, the same reference numerals as in the previous embodiment are given the same reference numerals as those in the previous embodiment, and the letter "e" is added to the parts that are considered to have the same or equivalent structure in terms of function, and redundant explanations are omitted. (Furthermore, in the following example, the same idea is given, and the alpha alphabet f is added to omit the redundant explanation.) Next, an embodiment of the present application will be described based on FIG. 4. In this example, large radioactive waste 1a
is melted directly without being subjected to size reduction as in the previous example. That is, the large-sized radioactive waste 1a is gripped by the gripper 33 of the melting device 31. This gripper 33 is configured to move up and down and rotate relative to the furnace body 32. Further, the furnace body 32 is equipped with a plurality of plasma torches 34. The waste 1a gripped by the gripper 33 is moved up and down or rotated, and is sequentially melted from its lower end by the high temperature plasma arc emitted from the torch 34. The melted waste becomes drops and drips into the container 6f. Container 6 like this
Once the drops are dripping into f and it eventually becomes full, the container 6f is sealed and moved to storage, as described above.

As described above, in the present invention, when the radioactive solid waste 1a is packed in the container 6f, the waste 1a larger than the container 6f is melted by the plasma arc from the plasma torch 34, and the melted waste is Drops can be dropped into the container 6f and packed there, and there is an effect that a very large waste can be packed into a much smaller container. This has the effect of helping to save space when storing the radioactive waste, since even if the waste is originally large in volume, the area required for storage can be reduced.

Moreover, in the above case, even if the waste 1a is very large, the plasma torch 34
Since the waste material 1a is irradiated with a plasma arc, which is stable in its emission direction, it is possible to accurately irradiate the targeted location and melt it. This has the effect that even a small container 6f can be accurately packed into the container.

Furthermore, in the above case, the radioactive waste is melted in a suspended state and the melted drops are dropped directly into the storage container 6f, so the container for melting the waste and the melted material are poured into the storage container. This has the effect of completely eliminating the need for separate equipment such as a Of course, in such cases, it is necessary to dispose of secondary waste generated when using electric furnaces (refractories and pouring equipment for electric furnaces are contaminated with radioactivity, so a lot of secondary waste is generated during repairs). ) is not necessary at all, and has the excellent effect of being able to solve the problems associated with the disposal of secondary waste in advance.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the treatment process of radioactive waste, Fig. 2 is a cross-sectional view showing the composition of radioactive waste, Fig. 3 is a vertical cross-sectional view showing different embodiments of the container, and Fig. 4 is an embodiment of the present invention. A diagram showing a container packaging device for radioactive waste. 1... Radioactive waste, 6... Container, 34... Plasma torch.

Claims (1)

[Claims] 1. A place to keep a container that can be used for storage, a gripper to grip the radioactive solid waste at a position above the container placed in the above place, and a radioactive waste gripped by the gripper. and a plasma torch for irradiating the solid waste with a plasma arc, the radioactive solid waste is melted by the plasma arc above the container placed in the above location, and the melted waste is transferred to the container. A container filling device for radioactive solid waste, characterized in that the radioactive solid waste is packed into the container by dropping the radioactive solid waste into the container.