JPS6254199A - Method of processing radioactive waste aqueous solution - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a method for treating an aqueous radioactive waste solution suitable for use in solidifying an aqueous radioactive waste solution such as an aqueous tritium solution using cement.

(b), Conventional technology When treating a radioactive waste aqueous solution such as a tritium aqueous solution, conventionally, cement is kneaded using the aqueous solution, and the kneaded cement is put into a container such as a drum pipe. It was solidified and stored in that state.

(C) 2 Problems to be Solved by the Invention However, since mixing is performed with water containing radioactive waste, when the cement adhering to the mixer is cleaned and removed after work, the removed material also contains radioactive materials. As a result, secondary waste will be generated.

In order to eliminate the above-mentioned drawbacks, the present invention aims to provide a method for processing a radioactive waste aqueous solution that can significantly reduce the generation of secondary waste when processing the radioactive waste aqueous solution. It is something.

(d) Means for solving zero problems, that is, the present invention performs dry kneading of cement and aggregate in a sub-zero atmosphere, and at that time, micronized particles produced from a radioactive waste aqueous solution are Ice is put into the cement and mixed, and the cement 1- after the dry mixing is put into a container and heated to melt the ice mixed in. It is constructed in such a way that the ice reacts with the surrounding cement, causing the cement to solidify.

(e) Zero effect With the above-described configuration, the present invention can maintain a dry state until the radioactive waste aqueous solution is mixed with cement in the state of fine particle water and poured into a container. act.

(f), Example Examples of the present invention will be specifically described below.

When treating a radioactive waste aqueous solution such as a tritium aqueous solution, first, aggregate such as sand is added to cement in a dry state and dry mixing is performed. The purpose of dry mixing (Part 2) is to mix cement and aggregate evenly, but during this dry mixing, ice in the form of fine particles made from an aqueous radioactive waste solution is simultaneously added to the cement and mixed. This work is carried out at sub-zero temperatures (here, "sub-zero" means a temperature below the freezing point of an aqueous solution. The same applies hereinafter), and therefore the ice mixed with cement is solid. and other aggregates in a dry state. The grain size of the ice is preferably similar to that of cement, or as close as possible to the size of cement particles, and ice with this grain size is produced by applying ultrasonic vibrations to a liquid aqueous solution and atomizing it. The atomized aqueous solution is then instantaneously cooled.

In this way, once the dry kneading of fine particulate ice, cement, and aggregate at sub-zero temperatures is completed, the dry-kneaded cement is poured into a nuclear waste container such as a drum pipe in the same sub-zero atmosphere. , compression formed by tamping etc.
Seal. Next, when the sealed cement is forcibly or naturally heated, the ice made of radioactive waste in the compressed cement melts and turns into water, causing a hydration reaction with the surrounding concrete and solidifying and hardening. do. Since the ice in the concrete is thoroughly and uniformly mixed with the concrete by dry mixing, an aqueous solution containing approximately the theoretical hydration amount of water sufficiently causes a hydration reaction in the concrete and solidifies it. Therefore, no excess waste aqueous solution remains in the container, and the waste aqueous solution is completely sealed in the concrete.

In addition, fine particle freezing of nuclear waste aqueous solution is produced by blowing a solution atomized into fine particles at room temperature into a freezing room, etc., but the method for atomizing the solution is to apply the above-mentioned ultrasonic vibration to the aqueous solution. In addition to this method, various methods can be considered, such as one using the principle of mist blowing and one using the boiling current value due to low pressure.

(g) 0 Effects of the Invention As explained above, according to the present invention, cement and aggregate are mixed in air in a sub-zero atmosphere, and at that time, fine particles produced from a radioactive waste aqueous solution are By putting the ice mixed into the cement and dry-mixing it, and putting the dry-mixed cement into a container such as a nuclear waste container and heating it, the ice mixed in the cement is melted. Since the melted ice reacts with the surrounding cement to solidify the cement, the radioactive waste aqueous solution such as tritium aqueous solution can be handled in a dry state, that is, in a solid particle state, until it is poured into a container. This makes it possible to solve the problem of cement containing waste adhering to the mixer and the secondary waste generated when cleaning it, as in the case of water mixing.

In addition, since cement is solidified by a radioactive waste aqueous solution such as a tritium aqueous solution containing water at a theoretical hydration level,
After solidification of cement, there is less leaching of waste due to evaporation of excess water, resulting in high safety.

Applicant: Mitsui Construction Co., Ltd. Agent Patent attorney Phase 1) Shinji (1 other person)

Claims (1)

[Claims] Cement and aggregate are mixed in air in a sub-zero atmosphere, and at that time, micronized ice produced from an aqueous radioactive waste solution is poured into the cement and mixed in air, The dry-kneaded cement is put into a container and heated to melt the ice mixed in the cement, thereby causing the melted ice to react with the surrounding cement and solidifying the cement. A method for treating radioactive waste aqueous solution composed of