JPH02145997A - Overpacked container for radioactive waste - Google Patents

Abstract

PURPOSE:To diminish a deformation of a buffer material layer and a generation of a wrack and to prevent a deterioration of the buffer layer's protection effect by filling spaces between an inner wall of an overpacked container and a canister with the buffer material. CONSTITUTION:An overpacked container 4 is constituted with a main body part 6 of the container and a lid 7, a canister 3 containing a radioactive waste is housed in the container 4 and a buffer material 8 and 9 are packed into spaces between the canister 3 and the container 4. As the buffer material 8 filled in an upper part of the container 4 is fixed after the radioactive waste is brought in, an inner part of the material has a recessed shape and the shaped material is fixed to the lid part 7 to be able to be handled together with the lid 7, and also a knob 11 is provided so as to be controlled remotely. On the other hand, the buffer material 9 is shaped protrudingly to fit with a bottom shape of the canister 3 and several air vent holes are provided. Consequently, even in a case that an outer pressure works on the buffer material layer outside the container 4, a little doformation of the buffer material occurrs and a generation of wracks diminishes and thus an effect of the outer buffer material layer can be kept for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an overpack container for safely disposing of radioactive waste deep underground.

(Prior Art) Currently, all the waste discharged from nuclear facilities such as nuclear power generation is stored within nuclear facilities as radioactive waste, and the amount of waste has become enormous. Therefore,
Various methods are being considered for categorizing radioactive waste into radioactive levels and disposing them according to their radioactive levels. Of these, deep ocean disposal and geological disposal are being considered as final disposal methods for particularly high-level radioactive waste. There is. Since the former deep-sea disposal poses international problems, the latter geological disposal is considered more realistic. Geological disposal involves transporting high-level radioactive waste into deep geological formations, several hundred meters underground, and isolating radioactive waste from the human environment using multiple barriers consisting of a combination of natural and artificial barriers. I have a basic idea.

As shown in Figure 4, the structure of the artificial barrier is as follows: a solidified body 2 in which radioactive waste is solidified in a bedrock 1;
A canister 3 for accommodating these, an overpack container 4 for accommodating these, and a buffer material layer 5 between the overpack container 4 and the rock 1 has been proposed.

Among these, the buffer material layer 5 has the function of preventing groundwater from entering the overback container and the function of suppressing the rate of leakage of radionuclides from the solidified body to the bedrock layer. plays an important role in ensuring the safety of geological disposal. ,.

(Problem to be solved by the invention) By the way, in this type of underground dumping of radioactive waste,
In order to ensure the safety mentioned above, it is important that the buffer material layer is densely packed, and there are few voids in the center area surrounded by the buffer material layer, that is, in the overback container. It is also important that If there are many voids in the center, when an external force is applied to the first buffer material layer due to an earthquake or other reason, the buffer material will deform and cracks will occur, reducing the protective effect of the buffer material layer. Because it does.

The present invention was made in view of the above circumstances, and its purpose is to provide an overback container for radioactive waste that can ensure safety over a long period of time even when used for geological disposal of radioactive waste. be.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an overpack container for containing radioactive waste, which is produced when a canister containing radioactive waste is inserted into the container body. The present invention is characterized in that a gap between the canister and the inner wall of the container body is filled with a buffer material.

(Function) In the present invention, since most of the voids inside the overback container are filled with the buffer material, even if an external force is applied to the buffer material layer on the outside of the overback container, the buffer material layer is less deformed and cracks etc. The occurrence of is reduced. Therefore, it is possible to prevent the protective effect of the buffer material layer from decreasing.

(Example) Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an overpack container showing an embodiment of the present invention. The overpack container 4 is composed of a container main body part 6 and a lid part 7, and a canister 3 containing radioactive waste is housed inside the overpack container 4.

Since there are normally spaces at the top and bottom between the canister 3 and the overpack container 4, these spaces are filled with buffer material 8.9.

The buffer material filled in the upper part of the overpack container 4 has a concave interior as shown in FIG. 2, and is fixed to the lid 7 of the overpack container with adhesive or the like. It can be handled together with. In addition, the buffer material 9 filled in the lower part of the overpack container 4 has an upwardly convex shape to match the bottom of the canister 3, as shown in FIG. Several holes 10 are provided. This lower buffer material 9 is placed in the bottom of the overpack container 4 before it is introduced into the hot cell. Therefore, there is no need for remote control when inserting the lower buffer material 9, but since the upper buffer material 8 is attached after containing the radioactive waste, it can be handled as one with the lid as described above. A knob portion 11 is provided for remote control.

Incidentally, as the buffer material, it is appropriate to use a material with long-term stability such as that used in the buffer material layer of an artificial barrier, and for example, ben-1-nite, synthetic resin, etc. are preferable.

(Effects of the Invention) As explained above, according to the present invention, even if an external force is applied to the buffer material layer on the outside of the overback container for some reason, the buffer material is less deformed and the occurrence of cracks is reduced. The effect of the buffer material layer provided on the outside of the overpack container is maintained over a long period of time. Therefore, the reliability of the safety of radioactive waste geologically disposed of by the present invention can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an overpack container according to an embodiment of the present invention, FIG. 2 is a perspective view of the lid of the overpack container of FIG. 1, and FIG. 3 is a bottom view of the overpack container of FIG. 1. FIG. 4, a perspective view of the buffer material to be filled, is a conceptual diagram of conventional geological disposal of high-level radioactive waste. 1... Bedrock 2... Radioactive waste solidified body 3... Canister 4... Overpack container 5... Buffer material layer 6... Container body of overpack container 7... Overpack Container lid 8.9 Buffer material 10 Air hole 11 Knob (8733) agent

Claims (1)

[Claims] In overpack containers containing radioactive waste,
Radioactive waste, characterized in that the gap between the canister and the inner wall of the container body, which is created when a canister containing radioactive waste is inserted into the container body, is filled with a buffer material. Overpack container for things.