JPH0484800A - Method of solidifying radioactive waste - Google Patents

Abstract

PURPOSE:To obtain a sound solidified body with high waterproof by performing solidification after the operation for painting the hydrophobic substance in a solidification vessel is performed. CONSTITUTION:After the moisture of waste resin is adjusted from a waste resin tank 1 through a dehydrater 2, it is introduced into a kneading tank 6 with a mixer 7. In a solidification system, a specified quantity of cement from a cement silo 3 is introduced into the kneading tank 6, a specified quantity of water from a kneading water tank 4 is put therein and a specified quantity of a water reducing agent and the like from an addition agent hopper 5 is introduced therein. A solidification vessel 11, for instance, is previously treated in a hydrophobic compound tank in which silicone grease of a low coefficient of viscosity and the like and mixture of grease are put. The previous disposal is performed by painting on the inner wall face of the tank 11 through spray drive power 9 and a spray nozzle 10. After the painting for about 30 minutes the vessel 11 is carried to the lower part of the kneading tank 6, radioactive waste resin homogeneously kneaded is charged therein from the kneading tank 6 to form a solidified body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for solidifying radioactive waste, and particularly to a method for producing a solidified material with excellent water resistance.

[Conventional technology]

Inorganic solidification of cement, water glass (alkali silicate), etc. is a treatment method for so-called low-level radioactive waste, such as concentrated waste liquid, used ion exchange resin, and miscellaneous solids generated from nuclear power plants and nuclear fuel reprocessing facilities. It is known that solidification treatment is performed using materials.

The solidifying material used for this purpose has excellent long-term durability and hardly deteriorates even under adverse conditions where the solidified waste material is submerged in water. However, in order to further improve the durability, attempts have been made to add about 5% of fiber to the solidifying material, as described in Japanese Patent Application Laid-Open No. 60-202398.

[Problem to be solved by the invention]

In addition to the low-level waste mentioned in the conventional technology, it has been devised that so-called medium-level waste, which has a specific radioactivity of more than an order of magnitude, can be disposed of on land after being solidified with cement. ing. In this case, since the specific radioactivity is high, it is desirable to further improve the durability of the solidified material and ensure its integrity for several hundred to several thousand years.

Conventional low-level solidified waste materials have shown sufficient performance considering the durability of the solidified materials after being submerged in water.

A further object of the present invention is to devise a method in which the solidified material itself is not exposed to water even if it is submerged in water in order to ensure its health over a long period of time, and thereby to produce a long-term stable solidified material of radioactive waste. The object of the present invention is to provide a solidification method.

[Means to solve the problem]

In order to achieve the above object, the present invention performs a solidification treatment after applying an operation of a hydrophobic substance in a solidification container.

[Effect]

The hydrophobic substance forms a waterproof layer on the inner side of the drum or lined re-drum, forming a water-stopping multilayer structure. Even if water were to infiltrate from the outside for some reason, this thin layer has a permanent water-repellent effect, so it can be prevented to the maximum extent from penetrating into the solidified body. Therefore, the health of the assimilated body is further improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. In this example, a process for simply solidifying radioactive waste resin will be exemplified. Waste resin discharged from a nuclear power plant or other nuclear facilities is collected and stored in a waste resin tank 1. The waste resin is fed from a waste resin tank 1 through a dehydrator 2 to adjust its moisture content, and then introduced into a mixer 6 having an agitator 7.

On the other hand, in the solidification phase system, a predetermined amount of cement is introduced from the cement silo 3, a predetermined amount of water is introduced from the kneading water tank 4, and a predetermined amount of water reducing agent, fluidizing agent, etc. is introduced from the additive hopper 5 into the kneading tank 6. . In the kneading tank 6, the mixture is sufficiently and uniformly kneaded by the stirrer 7.

On the other hand, on the solidification container side, cement or PIC (polymer impregnated concrete) is already made inside the drum. The solidification container is introduced into the pretreatment stage using a mobile device. Here, the hydrophobic compound tank 8 contains a low viscosity silicone grease, silicone oil, or a mixture of silicone oil and grease. Other effective substances include MMA (methacrylic acid resin),
There are organic polymer compounds such as paraffins. However, silicone-based hydrophobic compounds are preferable in terms of workability and ease of compatibility with assimilable materials. The hydrophobic compound is applied from the hydrophobic compound tank 8 to the inner wall surface of the solidification container via a spray power 9 and a spray nozzle 10.

Approximately 30 seconds of application has been found to be sufficient, although there are usually nozzle and power factors. After about 30 seconds of application, the assimilation vessel 11 is transported to the lower part of the kneading tank 6 by means of a mobile device. Here, the radioactive waste resin homogeneously kneaded with the solidifying material is injected from the kneading tank 6 to form the assimilated body 12. It was confirmed that curing was almost completed in about two weeks after the injection, and that the internal coating layer of the solidified material assimilated container was completely solidified.

〔Effect of the invention〕

According to the present invention, since a hydrophobic substance can be introduced between the solidification container and the radioactive waste solidification section to create a solidified body, a healthy solidified body with higher water resistance can be created compared to conventional assimilated bodies. It can be easily made.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. 1... Waste resin tank, 2... Dehydrator, 3... Cement silo, 4... Kneading water tank, 5... Additive hopper,
6... Kneading tank, 7... Stirrer, 8... Hydrophobic compound tank, 9... Spray power, 1o spray nozzle,
11 solidification container, 12... solidification body.

Claims (1)

[Claims] 1. A method for solidifying radioactive waste, which comprises applying a hydrophobic substance to the inside of a solidification container in advance when solidifying the radioactive waste. 2. In claim 1, the hydrophobic substance is paint,
A method for solidifying radioactive waste, which is an organic polymer compound such as oil or an inorganic polymer compound such as silicone goose or silicone oil. 3. A method for solidifying radioactive waste according to claim 1, in which the application method includes spraying, pouring, or directly applying with a brush.