JPS6117995A - Method of treating radioactive ion exchange resin - 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 (Field of Industrial Application) The present invention relates to a method for the purposeful treatment of radioactive ion exchange resins by capturing radioactive substances discharged from atomic couplants.

(Prior Art) Various methods for treating radioactive ion exchange resins (hereinafter simply referred to as @resin for simplicity) have been studied, but unfortunately, none has yet been put to practical use.

Typical methods and their drawbacks are listed below.

(Incineration method: Literally a method of incinerating resin, but if the radioactivity level contained in the resin is high, the amount of radioactivity contained in the combustion exhaust gas will also increase, so it is not recommended for exhaust gas treatment equipment. Excessive radioactive decontamination performance will be required.In other words, the exhaust gas treatment equipment will become complicated and large-scale.The concentration of radioactive substances in the incineration ash will increase, making it difficult to handle.

(2) Pyrolysis method: This is a method in which the supply of oxygen is cut off and the decomposition is carried out at high temperatures, and then the decomposed gas is combusted.Although it produces less dust compared to the incineration method, the pyrolysis step is redundant. This does not change the fact that the radioactive material concentration in the product is high.

(3) Chemical decomposition method: x for chemical reactions with chemicals
! This method oxidizes and decomposes 11 resin, but since strong acids and oxidizing agents are handled at high temperatures, corrosion of the equipment's constituent materials becomes a problem.

(4) M-contacting method: This is a method of encircling resin K with cement, asphalt, polymers, etc., but since the resin is an organic substance, the solidified product lacks long-term stability. .

(Problems to be Solved by the Invention) The present invention has been made in order to eliminate all the drawbacks of the above-mentioned conventional methods. It reduces the concentration of radioactive materials, reduces the amount of radioactivity contained in the incinerator exhaust gas, reduces the burden on the exhaust gas treatment system, and provides a reliable way to confine high-level radioactive materials in assimilators. That is.

(Means for solving all the problems) The present invention solves the problem of radioactive substances (Os-13
7, Elr-90, Co-6D, etc.), transferred to an inorganic adsorbent such as zeolite, and the resin with reduced radioactivity is incinerated in an incinerator, and the inorganic material that has completely absorbed radioactivity is subjected to a hydrothermal synthesis reaction. This is to turn it into rock and make it into a highly reliable solidified body.

That is, the present invention transfers the radioactive substances contained in the radioactive ion exchange resin to an inorganic adsorbent using a solvent as a medium, and the ion exchange resin whose nursery radioactivity has decreased is incinerated in an incinerator to adsorb the radioactivity. Inorganic adsorbent is a treatment method for radioactive ion exchange resin characterized by turning it into rock by hydrothermal treatment.

Broadly speaking, the present invention is a technology that combines an adsorption technology using an inorganic adsorbent, an incineration technology, and a hydrothermal synthesis technology.

Adsorption technology and incineration technology are well-known technologies, so their explanations will be omitted. Hydrothermal synthesis reaction is a method of synthesizing substances and growing crystals under conditions of pressure and temperature above the critical point of water. By holding it at a critical point, the ionic reaction of the dissolved mineral components is significantly accelerated, and the precipitation and growth of crystal nuclei occur almost instantaneously, so it is completed over a geologically long period of time. This technology allows rocks to be created artificially in a short period of time.

According to the present invention, since most of the radioactive materials have been removed from the resin supplied to the incinerator, subsequent treatment becomes easy, that is, exhaust gas treatment and incineration ash handling become easy. In addition, zeolite, which is an inorganic adsorbent, is a material suitable for hydrothermal synthesis and produces rocks of high quality (high strength, minimal radioactive leaching rate, long-term stability).

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. 1. ◎ The resin 1 is first received in a resin receiver tank 2, and a predetermined amount of resin is loaded into a resin packed tower 4 by a total resin supply pump 3. The resin packed tower 4 has a resin receiving port, a discharge port, and an inlet and an outlet for circulating the extract. Various solutions can be used as the extract, but a tartrate solution is suitable. The extract is circulated by the extract circulation pump 8 in a closed loop of the resin-packed column 4 -> the inorganic adsorbent light-packed tower 6 -> the extract tank 7 -> the extract circulation pump 8 . Zeolite is suitable as an inorganic adsorbent.
A predetermined amount of inorganic adsorbent is loaded into the inorganic adsorbent packed tower 6 from the line 5 in the figure. When the extract is circulated in the closed loop for a predetermined period of time, the radioactive substances (Os-137, 5r-9) held in the resin are removed.
0, etc.) are separated into the resin extract, and the 70% are adsorbed to an inorganic adsorbent (zeolite). In this way, most of the radioactivity is transferred from the resin to the inorganic adsorbent, so the resin 1 is then discharged from the lower part of the resin packed tower 4, the incinerator resin receiver is sent to the tank 11, and then the incinerator resin is supplied. It is supplied to an incinerator 13 by a pump 12 and is incinerated.

Although FIG. 1 shows the case of a fluidized bed type incinerator, the spirit of the present invention will not be impaired even if the incinerator is of a narrow type. In a fluidized bed type incinerator 13, combustion air 14 is introduced from the bottom.
The resin is blown into the fluidized bed and burns efficiently. Ash is sent from the upper part of the incinerator 13 to a cyclone 15, and most of the ash is separated and collected from the exhaust gas in the cyclone 15. After that, the exhaust gas is passed through the exhaust gas treatment device 16 (composed of a wet treatment device such as a Venturi scrubber and a high-efficiency gust filter made of glass fiber, etc.) to remove solids and harmful gases, and then becomes the exhaust gas 17. released into the atmosphere. On the other hand, the incinerated ash collected by the cyclone 15 is discharged from the lower part of the cyclone 15, and is solidified into a solidified body 19 in the incinerated ash solidification device 18. Here, the solidification device may be any of various known devices (cement solidification, plastic solidification, rock solidification, etc.).

On the other hand, in the inorganic adsorbent packed tower 6, a radioactive substance (Os-
137, 5r-90, etc.) is sent to the petrification device 9. This petrification device 9
utilizes a hydrothermal formation reaction, in which a small amount of NaOH aqueous solution is added to the zeolite and mixed well, then filled into a hydrothermal hot press and heated at a temperature (200
℃~300℃, pressure~300 kg/ctn”G)
A high quality solidified body 10 can be obtained by holding the solidified body 10 at

(Effects) The present invention provides the following effects through the above-described method and its effects.

(1) Since most of the radioactivity has been removed from the resin supplied to the incinerator, subsequent processing is extremely easy. Specifically, ■ Since the amount of radioactive materials in the combustion exhaust gas is small, the radioactivity removal performance required of the exhaust gas treatment device is low. In other words, a simple device is sufficient.

■ The low concentration of radioactive substances in incinerated ash makes it easy to handle. (It also makes it easier to solidify incinerated ash.) (2) The radioactive substances extracted from the resin are adsorbed to zeolite. It can be done.

[Brief explanation of drawings]

FIG. 1 shows the entire flow of one embodiment of the present invention. Sub-agent: 1) Akira Sub-agent Ryo Hagi Hara -

Claims (1)

[Claims] The radioactive substances contained in the radioactive ion exchange resin are transferred to an inorganic adsorbent using a solvent as a medium, and the ion exchange resin whose radioactivity has decreased is incinerated in an incinerator, and the inorganic adsorbent that has absorbed radioactivity is transferred to an inorganic adsorbent using a solvent. A method for processing radioactive ion exchange resin, which is characterized by turning into rock through synthesis.