TW201318007A - Method to decontaminate surface nuclides for thermal insulating perlite - Google Patents

Abstract

A Method is applied to decontaminate surface nuclides for thermal insulating perlite. A mixture of de-mineralized water and a cleaning agent was placed into a container followed by the contaminated perlite, which was immersed entirely into this mixed solution. The container was then put in an ultrasonic vibrator to undergo ultrasonication for 30 to 60 minutes and left undisturbed for 6 to 24 hours. Afterward, the container was ultrasonicated for an additional 10 minutes, prior to removing the perlite from the mixed solution. At this moment, the decontamination of perlite was complete. The implementation of this Method will benefit the management of contaminated perlite including its storage, handing and reuse.

Description

Pearl rock insulation material surface nuclear decontamination method

The invention relates to a method for decontaminating a surface of a perlite thermal insulation material, in particular to a physicist capable of effectively removing the nuclear pollution of the surface of the perlite thermal insulation material for subsequent storage, treatment or reuse.

According to the pipeline insulation material used in general nuclear power equipment, it is usually made of perlite material, and the insulation material is contaminated by the gas/liquid leakage of the nuclear energy equipment. Therefore, when the pipeline is repaired and replaced, the insulation material is removed. The replaced insulation material is classified as low-level radioactive waste.

Most of the domestic nuclear power plants are temporarily classified and stored in low-level radioactive waste storage warehouses, or subjected to ultra-high pressure compression treatment by a reduction center. International nuclear facilities usually use ultra-high pressure compression or high-temperature melting treatment to reduce the volume of perlite insulation material with radioactive contamination to less than 1/3 of the original volume, and then carry out temporary storage operations to wait for future transportation to the final disposal site. . However, in the case of high pressure treatment or melt treatment, it only reduces or stabilizes the perlite insulation material with radioactive contamination, and cannot effectively remove the nuclear species on the surface of the perlite insulation material. Therefore, even if the perlite insulation material with radioactive contamination is treated in this way, it is still radioactive and still classified as low-level radioactive waste, and subsequent storage and final disposal operations are still required in accordance with strict regulations.

However, after the replacement of the nucleus-contaminated perlite insulation material, the volume of the perlite-contaminated perlite insulation material is reduced by high-pressure treatment or molten treatment, and then sent to the radioactive waste warehouse for subsequent temporary storage. . The high-temperature melting method is to mix and mix the perlite with the flux and the adhesive, and after drying, the pellets are sent to the electric heating furnace to melt and reduce the volume at about 950 ° C, and after cooling, the high compressive strength and the high leaching index are formed. The glass melt solid, the experimental value of the volume reduction ratio can reach 10, but whether the waste barrel is full and the amount of foreign matter in the barrel affects the volume reduction effect in actual operation, so the actual volume reduction ratio is about 6-7 times. The plasma melting method uniformly mixes the granular granulated perlite and borax at a weight ratio of 4:1, and the purpose thereof is to lower the melting temperature of the perlite, increase the fluidity of the molten metal, and achieve vitrification. After that, it is packaged into a small package of 100 g by a baler, and then sent to a microwave plasma furnace for melting through a conveyor belt, and the temperature of the core is controlled between 1150 and 1220 °C. The treated glass cured body has a density of about 2.8 to 3.0 g/cm 3 and a volume reduction ratio of about 8 to 10 times. The former processing steps include classification, pulverization, addition of flux mixing, granulation, drying and sintering; the latter also requires classification, pulverization, addition of flux mixing and packaging, etc. The processing procedure is complicated and requires a large amount of energy at high temperatures. The Taipower reduction center uses a compression compressor with a compression force of up to 1,500 tons, which is a vertical compressor with a reduction ratio of about 3 to 5 times. Although the operation steps are simple, not all dry wastes are suitable for compression treatment. Some wastes tend to gradually return to their original shape when the pressure disappears, and their long-term stability still has doubts. Regardless of whether the means is ultra-high pressure compression or high heat melting, the main purpose of the treatment is to reduce the volume, and it is not effective to remove the nuclear pollution on the surface of the perlite insulation material. Therefore, even the perlite insulation material with nuclear pollution is at a high pressure. Or in the form of fusion treatment, it still has nuclear pollution, and is still classified as low-level radioactive waste. It is still necessary to carry out temporary storage and final disposal operations in accordance with strict regulations.

The academic community also uses supercritical carbon dioxide extraction to develop decontamination of perlite surface at high pressure (300 atm) and medium temperature (<100 °C). Due to the poor removal of inorganic materials by supercritical carbon dioxide, additional auxiliary solvents are needed to enhance Cleaning rate. However, it is still in the stage of metal ion simulation experiment, and has not yet entered the nuclear decontamination experiment.

In view of this, the inventors of this case have intensively discussed the above-mentioned problems of conventional inventions, and actively pursued solutions through years of experience in R&D and manufacturing of related industries. After long-term efforts in research and development, they finally succeeded in developing this book. Invented "the method of decontamination of surface minerals on perlite insulation materials" to improve the problems of conventional use.

The main object of the present invention is to effectively remove the nuclear pollution of the surface of the perlite insulation material for the purpose of subsequent storage, treatment or reuse.

For the purpose of the above, the present invention is a method for decontaminating the surface of a perlite thermal insulation material, comprising the following steps: Step 1: placing a perlite insulation material having nuclear pollution in a container; Step 2: in the container The demineralized water and the cleaning solution are added, and the perlite heat insulating material with nuclear pollution is completely immersed in the demineralized water and the cleaning solution; and step 3: the container in the second step is placed in the ultrasonic oscillating mechanism, and The perlite insulation material with nuclear pollution is oscillated for 30 minutes to 1 hour, then immersed for 6 to 24 hours, and finally oscillated for about 10 minutes to remove the nuclear pollution on the surface of the perlite insulation material.

In an embodiment of the invention, the cleaning solution can be a hydrochloric acid solution.

In an embodiment of the invention, the cleaning solution is an oxalic acid solution.

In one embodiment of the invention, the cleaning solution can be a sodium hydroxide solution.

In one embodiment of the present invention, the cleaning solution is mixed with demineralized water at a concentration of between 1 wt% and 5 wt%.

In an embodiment of the invention, the ultrasonic oscillation mechanism comprises a tank body, an ultrasonic oscillator disposed at the bottom of the tank body, and an aqueous solution injected into the tank body.

In an embodiment of the present invention, in the third step, a limiting unit may be disposed on the perlite thermal insulation material having nuclear pollution, thereby fixing the perlite thermal insulation material having nuclear pollution at a predetermined position.

Please refer to FIG. 1 to FIG. 6 , which are schematic diagrams of the first step of the present invention, a schematic diagram of the second step of the present invention, a schematic diagram of the third step of the present invention, a schematic diagram of the decontamination efficiency of the hydrochloric acid solution of the present invention, and the present invention. Schematic diagram of the decontamination efficiency of the oxalic acid solution and the decontamination efficiency of the sodium hydroxide solution of the present invention. As shown in the figure: The present invention is a method for decontaminating a surface of a perlite thermal insulation material, comprising at least the following steps: Step 1: placing a perlite insulation material 11 having nuclear pollution in a container 12.

Step 2: adding demineralized water 21 and cleaning solution 22 to the container 12, and completely immersing the perlite heat insulating material 11 having nuclear pollution in the demineralized water 21 and the cleaning solution 22, wherein the demineralized water 21 and the cleaning solution The mixture concentration of 22 is between 1 wt% and 5 wt%, and the cleaning solution 22 may be a hydrochloric acid solution, a sulfuric acid solution, an oxalic acid solution or a sodium hydroxide solution.

Step 3: The container 12 in the second step is placed in the ultrasonic oscillating mechanism 31, and the ultrasonic oscillating mechanism 31 includes a slot body 311, an ultrasonic oscillator 312 disposed at the bottom of the slot 311, and injected into The aqueous solution 313 in the tank body 311 is further disposed in the aqueous solution 313 of the tank body 311, and the perlite heat insulating material 11 having the nuclear pollution is fixed at a predetermined position by the limiting unit 32 to avoid ultrasonic waves. When the oscillation occurs, the ultrasonic oscillator 312 can be activated, and the demineralized water 21 and the cleaning solution 22 are oscillated for 30 minutes to 1 hour on the perlite heat insulating material 11 having nuclear pollution, and then immersed in 6~. After 24 hours, it will finally oscillate for about 10 minutes to remove the nuclear pollution of the surface of the perlite-protected perlite insulation material 11 for subsequent storage, treatment or reuse.

When the present invention performs the action of the second step, the hydrochloric acid solution, the sulfuric acid solution, the oxalic acid solution or the sodium hydroxide solution may be respectively used as the cleaning solution 22, and the hydrochloric acid solution, the sulfuric acid solution, the oxalic acid solution or the hydrogen is used. The decontamination efficiency of the sodium oxide solution is shown in Figures 4, 5 and 6, respectively, wherein the decontamination effect of the cleaning solution 22 is optimized with a hydrochloric acid solution, followed by a sulfuric acid solution, an oxalic acid solution and a sodium hydroxide solution.

In summary, the method for decontaminating the surface of the perlite thermal insulation material of the present invention can effectively improve various disadvantages of the conventional use, and can effectively remove the nuclear pollution of the surface of the perlite thermal insulation material, so as to facilitate the subsequent storage, treatment or reuse; The requirements for making the invention more progressive, more practical, and more in line with consumer use have indeed met the requirements of the invention patent application, and the patent application is filed according to law.

However, the above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto; therefore, the simple equivalent changes and modifications made in accordance with the scope of the present invention and the contents of the invention are modified. All should remain within the scope of the invention patent.

11. . . Perlite insulation material with nuclear pollution

12. . . container

twenty one. . . Mine water

twenty two. . . Cleaning solution

31. . . Ultrasonic oscillator

311. . . Slot

312. . . Ultrasonic oscillator

313. . . Aqueous solution

32. . . Limit unit

Figure 1 is a schematic view of the first step of the present invention.

Figure 2 is a schematic diagram of the second step of the present invention.

Figure 3 is a schematic diagram of the third step of the present invention.

Fig. 4 is a schematic view showing the decontamination efficiency of the hydrochloric acid solution of the present invention.

Fig. 5 is a schematic view showing the decontamination efficiency of the oxalic acid solution of the present invention.

Figure 6 is a schematic illustration of the decontamination efficiency of the present invention or sodium hydroxide solution.

11. . . Perlite insulation material with nuclear pollution

12. . . container

twenty one. . . Mine water

twenty two. . . Cleaning solution

31. . . Ultrasonic oscillator

311. . . Slot

312. . . Ultrasonic oscillator

313. . . Aqueous solution

32. . . Limit unit

Claims (8)

A method for decontaminating a surface of a perlite thermal insulation material comprises the following steps: Step 1: placing a perlite insulation material having nuclear pollution in a container; and step 2: adding demineralized water and a cleaning solution to the container; And completely immersing the perlite insulation material with nuclear pollution in the demineralized water and the cleaning solution; and step 3: placing the container in the second step in the ultrasonic oscillating mechanism, and performing the perlite insulation material with nuclear pollution 30 minutes to 1 hour of shock, thereby removing the nuclear pollution of the surface of the perlite insulation material. The method for decontaminating the surface of the perlite thermal insulation material according to the first aspect of the patent application, wherein the cleaning solution is a hydrochloric acid solution. The method for decontaminating the surface of the perlite thermal insulation material according to the first aspect of the patent application, wherein the cleaning solution is a sulfuric acid solution. The method for decontaminating the surface of the perlite thermal insulation material according to the first aspect of the patent application, wherein the cleaning solution is an oxalic acid solution. The method for decontaminating the surface of the perlite thermal insulation material according to the first aspect of the patent application, wherein the cleaning solution is a sodium hydroxide solution. The method for decontaminating the surface of the perlite thermal insulation material according to the first aspect of the patent application, wherein the concentration of the mixed solution of the demineralized water and the cleaning solution is between 1 wt% and 5 wt%. The method for decontaminating the surface of a perlite heat insulating material according to the first aspect of the patent application, wherein the ultrasonic oscillating mechanism comprises a tank body, an ultrasonic oscillator disposed at the bottom of the tank body, and injected into the tank body. Aqueous solution in the middle. According to the method for decontaminating the surface of the perlite thermal insulation material according to the first aspect of the patent application, wherein the third step is to provide a limiting unit on the perlite thermal insulation material with nuclear pollution, thereby fixing the nuclear pollution. Perlite insulation is at the intended location.