JPS60133399A - Method of solidifying radioactive washing waste liquor - 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 [Technical Field of the Invention] The present invention relates to a method for assimilating radioactive laundry waste liquid using a cement assimilation method.

[Technical Background of the Invention and Problems Therein] Generally, waste liquid from washing clothing and the like generated from nuclear facilities has an extremely low radioactivity concentration, so it is often diluted and released into the environment. However, such release of radioactive laundry waste into the environment is not necessarily desirable from the perspective of environmental preservation, so some nuclear facilities concentrate radioactive laundry waste and then turn it into a slurry and store it in drums. things are being done. By the way, if the contents are simply sealed in drums like this, there is a risk that the contents will leak out due to corrosion or damage to the container during a long storage period. Therefore, radioactive laundry waste liquid should be solidified and stabilized like other radioactive waste liquids. It is desirable to make it into a form. For this reason, a cement assimilation method is currently being proposed as a solidification treatment method for radioactive laundry waste.

However, it has been revealed that in the cement 1-assimilation method of radioactive laundry waste liquid, the assimilation of cement is inhibited by the action of surfactants, which are the main components of detergents, resulting in insufficient solidification.

For this reason, when solidifying radioactive laundry waste liquid, powdered activated carbon is added and mixed to the radioactive laundry waste liquid in advance to adsorb and remove the surfactant contained in the detergent, and then a flocculating precipitant is added to solidify the activated carbon. After separation, the activated carbon is mixed with cement to solidify it, or the activated carbon that has been precipitated and separated is dehydrated in a centrifugal dehydrator to reduce its volume, and then mixed with cement to solidify it.

However, the former method has poor volume reduction properties, and the latter method has the disadvantage that precipitates adhere to the outlet of the centrifugal dehydrator and cannot be discharged.

[Object of the Invention] The object of the present invention is to provide a method for solidifying radioactive laundry waste liquid that does not require the separation of C1 activated carbon and has a high capacity for volume reduction.

[Summary of the Invention] That is, the method for assimilating radioactive laundry waste liquid of the present invention is characterized in that, after concentrating the radioactive laundry waste liquid, the concentrated liquid is mixed with activated carbon and solidified with cement.

As the radioactive laundry waste liquid to be applied to the present invention, a liquid mainly using a nonionic surfactant as a detergent is preferable because it does not cause foaming when concentrated.

Further, as a concentrating device, a commonly used evaporator concentrator, thin film scraping dryer, etc. can be used.

As the activated carbon added to the radioactive laundry waste liquid concentrated by these concentrators, powdered activated carbon (average particle size: 50 μm), which is commonly used for water treatment, can be used.

Furthermore, in the present invention, mixing with the concentrated liquid such as activated carbon,
This liquid mixture and cement can be mixed using, for example, a conventional cement mixing machine as shown in the drawings.

That is, a stirring shaft 2 to which stirring blades 1.1 are fixed in upper and lower stages is arranged in a drum can 3 serving as a storage container, and a motor (
(not shown) rotates the stirring shaft 2 and rotates the drum can 3.
Activated carbon and concentrated liquid inside.

After kneading, Cement I~ is added to these mixed liquids and kneaded.

In the present invention, radioactive laundry waste is sufficiently reduced in volume by concentration, and then treated with activated carbon to solidify the slag mixed with cement, resulting in a strong and healthy assimilate.

[Embodiments of the invention] Embodiments of the present invention will be described below.

In addition, in the following examples, simulated washing was performed using a detergent having the composition shown in Table 1 (manufactured by Nippon Oil & Fats Co., Ltd., trade name: Tosuna Soap H) as radioactive laundry waste liquid, and the obtained laundry waste liquid was poured into a drum. A concentrated solution concentrated using a type concentrator was used.

In addition, activated carbon (powder activated carbon (Hitachi Carbon Industries, Ltd.)
Type 0 blast furnace cement (manufactured by Nippon Cement Co., Ltd.) was used as the cement, and a cement mixer shown as a rough mixer was used.

(Left below) Example 1 Ioo, C drums were filled with 17 kg of powdered activated carbon, set in a cement mixer to start mixing, and in this state, 50p of washing W1 concentrated waste liquid (liquid temperature 40°C, concentration 8%) ) was poured into the mixture and thoroughly kneaded. Next, 100 kg of cement was filled into this drum and kneaded for 10 minutes to produce a cement assimilate.

Example 2 A 100β drum was first filled with 50 volumes of washing wBm waste liquid (liquid temperature 40°C, concentration 8%) and set in a cement mixer, then filled with 17 kg of powdered activated carbon to start mixing, and was filled with 1 ook of cement and mixed for 10 minutes to produce a solidified cement body.

Next, we measured the physical properties of the obtained cement solidified material, which serve as standards for ocean dumping, and the results shown in Table 2 were obtained, indicating that there was a healthy solidified material that exceeded the standard values. confirmed.

(Left below) [Effects of the Invention] As is clear from the above examples, according to the present invention, radioactive laundry waste liquid is sufficiently reduced in volume by concentration, then treated with activated carbon and kneaded with cement. It is extremely easy to operate, has high volume reduction properties, and significantly reduces the generation of radioactive waste.

Moreover, the solidified material obtained is also strong and sound.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view of a cement 1 to kneader used in an example of the present invention. １・・・・・・・・・・・・Stirring blade 2・・・・・・・・・Stirring shaft 3・・・・・・・・・Drum

Claims (4)

[Claims] (1) A method for solidifying radioactive laundry waste, which comprises concentrating the radioactive laundry waste, then mixing the concentrated liquid with activated carbon to form a cement body. (2) The method for assimilating radioactive laundry waste liquid according to claim 1, wherein the detergent in the radioactive laundry waste liquid is a nonionic detergent. (3) The method for solidifying radioactive laundry waste liquid according to claim 1, wherein the radioactive laundry waste liquid is concentrated using an evaporator type concentrator or a thin film scraping dryer. (4) The method for solidifying radioactive laundry waste liquid according to claim 1, wherein the activated carbon is powdered activated carbon.