KR100945744B1 - Disposition method and its process for protective products manufactured by polyvinylalcohol - Google Patents

Abstract

PURPOSE: A method for disposing PVA(Polyvinyl Alcohol) protective products is provided to reduce the amount of combustible wastes by disposing of the PVA protective products through decontamination, concentration, and drying processes. CONSTITUTION: A PVA protective product is collected and separated(S1). The PVA protective products are firstly cleaned in a vacuum condition by an ultrasonic cleaning process(S2). The PVA protective products are then dissolved and concentrated(S3). A PVA solution is filtered to remove radioactive materials(S4,S6). The residual radioactive materials, after a second filtering process, are removed by ion absorption(S7). The radioactive concentration of the PVA solution is evaluated(S8). The PVA solution is stored(S9). A non-radioactive PVA solution is processed(S10).

Description

Disposal method and its process for protective products manufactured by Polyvinylalcohol}

The present invention relates to a method for decontaminating a protective article made of polyvinylalcohol (PVA) used in nuclear power plants by less than MDA, and self-disposal. In addition to overcoming the problem, it is a low and medium-level waste reduction technology that can maximize the economical and eco-friendly advantages that can overcome the disadvantages of the incineration treatment. More specifically, the present invention dissolves and concentrates low and medium-level radioactive wastes of PVA materials generated in a nuclear power plant in recent years to decontaminate radioactive materials to below MDA using a flocculation and filter system, and then concentrate or dry the final PVA solution. It relates to a processing method to dispose.

In the case of domestic nuclear power plants, when the radioactive waste storage space is in saturation level, due to the delayed operation of Gyeongju's mid- and low-level radioactive waste disposal site, which is delayed by two years from the end of 2009, it is very interesting to develop technologies to reduce the amount of waste generated from nuclear power plants. The situation is emerging as a challenge. It is reported that the cost of permanent disposal of wastes generated during the operation of nuclear power plants also exceeds about 7.4 million won per drum, so the payment of these waste disposal costs will be a significant burden on nuclear operators.

Table 1 shows the recent trends in waste generation from domestic nuclear power plants. As a result of analyzing the waste generated from nuclear power plants from 2006 to 2008, it was found that the amount of mixed waste generated 83%, of which the combustible waste accounted for 55.8%. Accordingly, there is a need for a fundamental alternative for reducing the amount of flammable waste generated in the waste collected.

TABLE 1

      ※ Reference: White Paper on Nuclear Power Generation 2006 ~ 2008

In the United States and Mexico, more than 85% of nuclear power plants are involved in reducing laundry room operation costs and waste generation through the use of various water-soluble protective products such as work clothes, salt-washing paper, overshoes and leaking rods made of PVA. According to the report, the ratio of waste reduction due to the use of PVA protective equipment is reported to be 10,000: 1.

The technology to reduce the amount of combustible waste generated from nuclear power plants can be classified into the technology of blocking the source and the technology of treating the generated waste. In general, the most effective treatment of combustible waste is incineration. However, considering the domestic reality, it is difficult to incinerate radioactive waste in the plant and finally dispose of it, which is inconsistent with the national sentiment, and it is contradictory to the operation of eco-friendly nuclear power plants by nuclear power companies, and indiscriminate environment of volatile radioactive materials if management is neglected. Chronic environmental pollution may result from emissions to the furnace. Therefore, the way to drastically reduce the amount of radioactive waste generated can be said to fundamentally block the generation of flammable waste. However, considering that flammable wastes are inevitably generated during the operation of nuclear power plants, fundamental solutions should be prepared to reduce the amount of wastes generated.

In this respect, the introduction of protective articles made of PVA materials is the answer. Unlike other high molecular materials, PVA material has a physical and chemical characteristic close to cotton and dissolves in water at 100 ° C, making it easy to decontaminate radioactive material of wastes made of PVA material below MDA. And, it can be treated biochemically, and because it is finally decomposed into CO ₂ and H ₂ O during treatment, it can be called a very environmentally friendly product.

In the case of domestic nuclear power plants, the use of PVA protection supplies has been gradually increasing since the first application in 2007, and the types of products used in nuclear power plants also absorb decontamination paper, vinyl, gumshoes, gloves, and leakage from initial work clothes. There are various changes such as rods.

U.S. Pat.No. 7,147,787 B2, Korean Patent Application No. 2002-0063896 discloses a final sanitary sewage system by decomposing PVA into organic acid through a device and method for complete dissolution, sterilization and removal of radioactive material of clothes, supplies, equipment and other products made from PVA. Provides a method and apparatus for processing. The patent is very high in terms of radioactive waste reduction effect and treatment cost by dissolving PVA material at 0.5-5w / v% and decomposing it into organic acid using OH radicals and then treating it with a general domestic sewage treatment stream. However, in the domestic nuclear industry, the external export of radioactive waste is strictly limited, and the treatment method is also limited to incineration, so it is virtually impossible to entrust it to the operating entity operating the biological treatment facility. Therefore, there is an urgent need for the development of an efficient PVA protective article processing technology suitable for the domestic reality.

Development of a treatment method that can fully utilize the eco-friendly characteristics of PVA protective products for the reduction of operating cost of nuclear power plants and the reconstruction of eco-friendly images of the nuclear power business through the introduction of PVA protective equipment that can drastically reduce the amount of combustible waste generated from domestic nuclear power plants. Should be.

The present invention has been made to solve the problems encountered in domestic nuclear power plants as described above, the object of the present invention is made of PVA resin that is introduced for the drastic reduction in the amount of combustible waste generated by more than 50% generated in domestic nuclear power plants It is to provide a treatment technique for the extended use of protective articles.

Another object of the present invention is to provide an environmentally friendly disposal technology that can meet the domestic sentiment by developing a method and apparatus for decontamination of waste of PVA material generated after use in nuclear power plants.

It is still another object of the present invention to provide an apparatus for treating radioactive waste, which can reduce the size of the apparatus and reduce the installation area of the plant, as compared with a conventional system for treating water-soluble radioactive waste.

The above and other objects of the present invention can be achieved by the present invention described in detail.

Protective article decontamination method made of the polyvinyl alcohol of the present invention, 1) collecting / separating the used PVA protective article; 2) a first washing step of pre-treating PVA protective article through ultrasonic cleaning under vacuum conditions; 3) dissolving / concentrating the PVA to secondary wash the protective article vacuumed by the primary wash step; 4) a primary filtering step of filtering the radioactive material present in the dissolved / condensed aqueous solution using a filter; 5) introducing a flocculant to treat the radioactive material in the untreated filtrate in the primary filtering and filtering the secondary; 6) ion adsorption step of removing radioactive material in untreated filtrate after secondary filtering; 7) evaluating the radiation concentration of the PVA solution from which the radioactive material has been removed and storing the concentrate; 8) a disposal step of treating the concentrated non-radioactive PVA solution.

In addition, the step 2) is preferably attached or absorbed to the water-soluble protective article to remove the beta nuclide present.

And the beta nuclide is preferably H-3 and C-14.

In addition, in order to increase the washing efficiency of the radioactive material attached or absorbed to the water-soluble protective article, it is preferable to form the inside of the multi-reactor in a vacuum atmosphere of 100 to 300 Torr.

And the water-soluble protective article is to be washed by the ultrasonic generator of the piezo-type in a vacuum atmosphere.

In addition, it is preferable that the filtrate circulation line is tangentially positioned on the outer circumferential surface of the multi-reactor to allow the filtrate to flow in a tangential direction.

And the multi-reactor is preferably connected to a heater tank for heating the inside of the multi-reactor in the step of dissolving / concentrating PVA.

In addition, the heater tank is preferably dissolved first by heating the multi-reactor to contain 5 to 15% by weight of PVA of the water-soluble protective article in the solution therein.

In addition, the solution in which the PVA is dissolved is preferably concentrated to 35 to 45% by weight so as to minimize the amount of liquid waste targeted for self-disposal.

In addition, it is preferable that the heater tank indirectly heats the multi-reactor by the heating jacket of pure water from which the ionic particles for indirectly heating the multi-reactor is removed.

And the pure water contained in the heater tank is preferably to be formed of a steam of 100 ~ 130 ℃ by the heater.

In addition, in the multi-reactor, it is preferable to promote PVA dissolution with hydroxyl radicals generated by adding hydrogen peroxide and iron salt to induce Fenton reaction upon primary dissolution of PVA.

And it is preferred to so as to induce the Fenton reaction by introducing hydrogen peroxide and ferrous salt solution at the time when the PVA material upon a primary dissolving PVA in the multi-reactor a 70-95% dissolution.

In addition, the hydrogen peroxide is injected into 0.3 ~ 1L _{H 2 O 2} / kg _{PVA protective clothing} of 35% by weight purity, iron _{salt solution} is preferably added to 0.1 ~ 0.5L _{iron salt solution} / kg _{PVA protective clothing} .

In addition, the iron salt solution is preferably added to a 500 mL bolometric flask with 6.25 mL of H ₂ SO ₄ (purity: 35%) and 2.18 g of FeSO ₄ 7H ₂ O into a bolometric flask, filled to 500 mL with distilled water, and purified to form an hour. Do.

In addition, the solution in which the PVA is dissolved is preferably heated and reduced in temperature at a temperature range of 80 to 85 ° C. and a pressure range of 100 to 300 Torr to evaporate water, and condensed evaporated water to be recycled into process water.

In the first filtering step, it is preferable to first remove radionuclides included in the concentrate using a filter having a diameter of 1 to 80 μm.

In addition, the flocculant introduced in the flocculant injection / stirring step is used simultaneously with the cation / anionic polymer flocculant of acrylamide series at pH 6.5 ~ 7.0, so that the dose is in the 0.2 ~ 1.0mL _polymer / L _{PVA solution} range It is desirable to allow removal of gamma nuclides in the wastewater.

And the injected flocculant to increase the decontamination efficiency by injecting agglomeration nuclei containing iron salt in the 0.2 ~ 1.0mL _{agglutination nucleus} / L _{PVA solution} ratio so that a stable floc is produced in a PVA solution containing a high concentration of organic matter It is desirable to.

In addition, the first filtering step and the second filtering step is preferably to filter the flocculant in the concentrate using a filter having a diameter of 0.2 ~ 80㎛.

In the ion adsorption step, the ion exchange media used for removing ionic nuclides is preferably in the form of metal oxides.

In addition, the disposal step of treating the PVA solution is preferably to be made by any one selected from the concentrated liquid self-disposal method or concentrated liquid dry cauterization disposal method.

According to the present invention, when the protective article is replaced with a protective article made of PVA material, it is possible to treat the MDA level using the PVA protective article decontamination apparatus developed through the present invention, and the final treated PVA solution is concentrated or dried after incineration The radioactive waste generated by the treatment can be "zeroed", resulting in the benefits of extending the life of the radioactive waste disposal site by reducing the amount of waste generated, as well as reducing the cost of permanent disposal.

In addition, PVA protective equipment decontamination equipment can be implemented in a small space because it can be implemented in a small mobile equipment is expected to be very beneficial in terms of equipment operation. Therefore, the introduction of PVA protection products in domestic nuclear power plants can expect various effects in terms of reducing the operating cost of nuclear power plants, reducing the amount of radioactive waste generated, and protecting and sanitary workers.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. These embodiments are provided to explain in detail the present invention to those skilled in the art. Accordingly, the shape of each element shown in the drawings may be exaggerated to emphasize a more clear description.

1 is a block diagram showing a protective article decontamination method made of a polyvinyl alcohol of the present invention, Figure 2 is a process diagram showing a protective article decontamination method made of a polyvinyl alcohol of the present invention, Figure 3 is shown in FIG. 4 is a cross-sectional view showing the multi-reactor shown in FIG. 3, FIG. 5 is a plan view showing the multi-reactor shown in FIG. 3, and FIG. 6 is made of the polyvinyl alcohol of the present invention. Figure 7 is a process chart showing a state in which the flocculation process is separated in the protective article decontamination method, Figure 7 is a graph showing the relationship between the concentration of PVA solution treated by the present invention and the cost of self-disposal.

As shown in Figures 1 to 6, the process according to the present invention, 1) collecting / separating the used PVA protective article (S1); 2) a first washing step (S2) of pretreating the PVA protective article by ultrasonic cleaning under vacuum conditions; 3) dissolving / concentrating PVA to decontaminate / dispose the protective article vacuumed by the primary washing step (S3); 4) first filtering step (S4) of filtering the radioactive material present in the dissolved / concentrated aqueous solution using a filter; 5) injecting a flocculant to treat the untreated radioactive material in the primary filtering (S5) and secondary filtering (S6); 6) ion adsorption step (S7) to remove the radioactive material in the untreated filtrate after the second filtering; 7) evaluating the radiation concentration of the PVA solution from which the radioactive material has been removed (S8) and storing the concentrate (S9); 8) a disposal step of treating the concentrated non-radioactive PVA solution (S10).

1) The collection / separation step (S1) of collecting in situ to separate insoluble materials,

PVA protective articles used in nuclear power plants are collected and stored in certain areas. The collected protective supplies are separated into a certain volume unit that can be processed by the multi-reactor 100 at a time. At this time, the protective supplies contaminated by oil and particulate matters to the protective supplies are visually classified into high-contamination protective clothing. In the case of the decontamination of these protective products, the low pollution protective clothing is treated step by step in the high pollution protective clothing.

The following Table 2 is a table analyzing the contamination status of PVA protective equipments generated from nuclear power plants. As can be seen from Table 2, the contamination of the overshoes worn on the work clothes and shoes worn in the radiation-contaminated areas is 1.75E + 02Bq / g and 1.52E + 03Bq / g, respectively, which is about 10 times more than the difference.

Therefore, by treating the high-contamination protective clothing after the low-contamination protective clothing decontamination is completed, it is possible to minimize the contamination of the device by the radioactive material, it is possible to obtain a better decontamination effect. PVA protective article separated through this process is put into the multi-reactor 100.

TABLE 2

2) vacuum washing step (S2) of pretreatment of the radioactive material on the PVA protective article by ultrasonic cleaning under vacuum conditions,

In step 2), the PVA protective article contaminated with radioactive material is first washed using ultrasonic waves in a vacuum condition to remove particulate matter, H-3, C-14 and other gamma nuclides as a primary, thereby protecting the PVA protective article. The decontamination efficiency can be increased by minimizing the radioactive material present in the solution upon dissolution. Water is supplied through the water supply line (L14) for the washing of the PVA protective article put into the multi-reactor 100. When a predetermined amount of water is supplied to the multi-reactor 100, the water supply valve is locked by the signal of the water level gauge 100a, and the vacuum pump 50 is operated to maintain the internal pressure of the multi-reactor 100 to 300 Torr. In step 2), ultrasonic vacuum impregnation cleaning was applied to the side of the multi reactor 100 to improve the cleaning efficiency of the PVA protective article.

According to the step 2), it is possible to increase the removal efficiency of contaminants by washing the protective article under vacuum conditions, and by circulating the liquid through the solution circulation line (L3) by the operation of the mixing pump 30 to the protective article It is easy to remove the particle radioactive substance attached. In addition, by applying an ultrasonic wave to the wash water by using the ultrasonic generator 102, higher washing efficiency can be expected. More specifically, the ultrasonic oscillator is suitable for the piezo type, the ultrasonic oscillator can increase the washing efficiency by installing on the side of the multi-reactor 100, the washing time is 0.5 ~ 1 hour / time, the number of recovery is 3 ~ 5 times / batch is suitable.

Compression means (7) installed on the upper portion of the multi-reactor 100 can dewater the protective article after the discharge of the washing liquid can increase the decontamination efficiency.

Gamma nuclide removal efficiency treated through step 2) is shown in Table 3. As can be seen from Table 3, in the case of protective clothing, the initial removal rate of 1.75E + 02 Bq / g was 3.93E + 01 Bq / g, which was about 77.6%, and overshoes 1.52E + 03 Bq / g. After washing at 5.27E + 02 Bq / g, it showed a removal efficiency of about 65.3%.

The washing liquid generated in the washing process can be discharged in connection with the nuclear power plant LRS system without any additional treatment, thereby reducing the burden on the generated waste liquid treatment.

[Table 3]

3) dissolving / concentrating the protective article after washing (S3)

PVA protective article first decontaminated through the washing step (S2) of the step 2) is a continuous dissolution and concentration process for effective secondary decontamination. PVA material is characterized by dissolving in water at 100 ℃, it can be used to prepare a PVA solution of a certain concentration.

After the washing process (S2) is completed, supply a predetermined amount of water required for dissolution through the water supply line (L14) to the multi-reactor 100, indirectly using the steam generated from the heater tank 300 Heating. In particular, the heating unit for heating the multi-reactor 100 is the primary heating of the water in the heater tank 300 with the heater 301 to generate steam of 100 ~ 130 ℃, wherein the generated high temperature steam is steam Through the supply line (L12) flows into the heating jacket 105 installed on the bottom of the multi-reactor 100 to indirectly heat the inside of the multi-reactor.

At the time of the multi-reactor inner temperature at which the PVA is preferably 95 ℃ starts to dissolve in water, the 30 minutes of more than 70 ~ 95% less than a 95% PVA to be soluble in water.

According to the present invention, after PVA dissolution, an effective filtering process (S4) and a second filtering step (S6) are performed, and a flocculant injection / stirring process step (S5) for floc formation by a flocculant is performed. ) And the concentrated liquid self-disposal step (S10-1) selected by the disposal step (S10) for treating the PVA solution or the concentrated liquid may be disposed of through the self-disposal step (S10-2a, S10-2b). The optimum PVA solution concentration considering the disposal cost was found to be in the range of 35-45 w / v%.

That is, the final 35 ~ 45w / v% PVA solution prepared in this step can be incinerated through the disposal step (S10-2a, S10-2b) can obtain a reduction effect of the disposal cost. 7 is a graph showing the self-disposal cost according to the concentration of the final decontaminated PVA solution. Self-disposal costs presented in this graph are calculated on the basis of 400,000 won per ton of non-radioactive waste.

The preparation of these concentrates described above can be obtained by the following detailed steps.

 PVA solution concentrated to 35 ~ 45w / v% is prepared through the secondary concentration process after the first 5 ~ 15w / v% solution preparation. In addition, in order to prepare the solution of the first 5 ~ 15w / v%, the Fenton reaction using hydrogen peroxide and iron salt should be accompanied during the dissolution process. Hydroxide radicals generated by the Fenton reaction can increase the dissolution rate by decomposing the polymer PVA material into low molecules, and the first and second filtering steps (S4, 1), which proceed continuously after the dissolution / concentration step (S3). In S6) it is possible to minimize the clogging of the filter.

In order to manufacture the first 5 ~ 15w / v% PVA solution, hydrogen peroxide and iron salt solution should be added when 95% of the PVA material is dissolved.In this case, 35% hydrogen peroxide is added as 0.3 ~ 1L _H2O2 / kg _{PVA protective clothing} . For iron salt solution, 0.1 ~ 0.5L _{iron salt solution} / kg _{PVA protective suit} is appropriate.

The heat of oxidation generated by the Fenton reaction can supply energy for dissolving PVA, thus acting as a stable energy source without the heater 301 operating. In addition, the PVA solution is maintained at 98 ~ 100 ℃ by the heat energy generated by the Fenton reaction to evaporate the water in the PVA solution. Water evaporated in the dissolution step is collected in the condensate storage tank 500 via the heat exchanger (400). This water evaporation may be closer to the concentration (35 ~ 45w / v%) to be obtained in the present invention by evaporating the water added in the initial excess.

According to the present invention, the dissolution step may be evaluated as a dissolution completion step when the temperature of the multi reactor down to 95 ℃.

When dissolution is completed, the vacuum pump 50 is operated to maintain the inside of the multi-reactor 100 at 100 to 300 Torr and concentrate the PVA solution. The technique of concentrating the solution under vacuum conditions can shorten the concentration time because of the excellent water evaporation efficiency in the waste liquid containing the high concentration organic matter.

Application of this concentration process can obtain the effect of reducing the disposal cost as shown in FIG.

All the steam generated during the operation of the process is condensed with water through the heat exchanger 400 is collected in the condensate storage tank 500, the collected condensate is reused in the dissolution / concentration process (S3) to zero the waste liquid generated Can be.

The PVA solution prepared through the dissolution / concentration step (S3) may undergo a first filtering step (S4) in a multi-reactor as shown in FIG. 2, and discharged into the coagulation bath 110 as shown in FIG. 6. It is also possible to build a separate filtering system.

4) The primary filtering step (S4) of filtering the radioactive material present in the dissolved PVA protective article aqueous solution by using a filter sequentially,

In order to remove particulate matter present in the prepared PVA solution, the filter is subjected to a first filtering step.

By removing the particulate matter present in the PVA solution through this step it is possible to maximize the radioactive material removal efficiency by the flocculant.

In the first filtering step, the filter device 200 having the 80 μm filter cartridge therein, the filter device 201 having the 20 μm filter cartridge therein, and the 1 μm filter cartridge having the filter pump 20 are embedded therein. The filter device 202 is sequentially passed through.

The types and concentrations of the nuclides removed through the first step are shown in Table 4 below.

The radioactive concentration of the dissolved / condensed 35w / v% PVA solution was 3.25E + 01 Bq / g, and the gamma nuclide after filtration using the 80 ~ 1㎛ filter decreased 61.5% from the first 13 species to 5 species. The total radiation concentration decreased to 2.94E-1 Bq / g. The final missing DF value was 110.5 through the first filtering step.

TABLE 4

The function of the primary filtering step in the present invention leads to the removal of radioactive material as well as the washing inside the multi-reactor 100. Bubbles that may be generated in the PVA dissolution step may contaminate the walls of the multi-reactor, and these contaminated materials may act as a source of contamination of the solution.

The filtrate discharged in the first filtering step is introduced into the multi-reactor 100 through the filtrate circulation line (L5). The inflow angle flowing into the multi-reactor is installed in the tangential direction of the outer circumferential surface of the multi-reactor as shown in FIG. 7 to form a swirl flow on the wall of the multi-reactor when the filtrate enters to wash the interior of the Malty reactor.

5) coagulant input (S5) and secondary filtering (S6) for treating untreated radioactive material in the first filtered filtrate

After the Fenton reaction, the PVA solution is present as a strong acid of pH 2-3. When the pH is low, the radioactive metal (M; Metal) ion is present in the form of M ^{2 +,} which is difficult to precipitate in water, so that it is difficult to effectively filter. In order to maximize the efficiency of removing radioactive material by the addition of coagulant, the pH is 7 It is preferable to adjust to. In addition, NaOH added to adjust pH can induce decomposition of hydrogen peroxide and precipitation of dissolved heavy metals that can remain after Fenton reaction, effectively acting to remove radioactive substances present in PVA solution. To provide a suitable pH condition.

In order to carry out the continuous filtration after dissolution, the prepared PVA solution temperature should be cooled to 35 ° C in a short time.

When cooling of the PVA solution is required, a cooling line L7 provided with a heat exchanger 401 may be used.

 This step is characterized by injecting a flocculant capable of removing gamma nuclides for further decontamination of the radioactive material present in the primary filtered PVA solution.

The flocculant to be introduced is characterized in that the cation and anionic flocculant are added separately.

In order to increase the coagulation efficiency, the pH of the PVA solution should be adjusted, and the optimal pH range is 6.5 to 7.0.

In order to promote effective floc formation by adding a flocculant, a flocculating nucleus containing iron salt is added before the flocculant is added.

According to the present invention, an acrylamide-based polymer is effective for removing gamma nuclides present in a solution containing a high concentration of organic matter, such as a PVA solution, and an appropriate dosage is 0.2-1.0 mL _polymer / L _{PVA solution.} More preferably, the dosage of 0.5 mL _polymer / L _{PVA solution} is appropriate.

The injected polymer can remove all gamma nuclides with positive and negative charges present in solution.

In order to efficiently operate the multi-reactor 100 of the present invention, the iron salt solution tank 61, the cation flocculant tank 62, the anion flocculant tank 63, the flocculant injection pump 60 is provided with a flocculant injection facility It is preferable. In addition, it is preferable to apply a syringe pump (Syringe pump (60)) for the effective injection of high viscosity flocculant.

According to the present invention, the rotation speed (RPM) of the mixing pump 30 is adjusted for effective mixing and flocculation of the flocculant introduced into the multi-reactor 100, and the mixing of the PVA solution is easily performed using the solution circulation line L3. Do.

In addition, according to the present invention, in order to completely mix the concentrate and the flocculant, as shown in FIG. 6, the flocculation tank 110 and the agitator 111 are separately installed and operated to separate the dissolution / concentration process and the flocculation / filtration process. It is possible to obtain a more stable decontamination effect by operating.

Table 4 shows the results obtained through the examples of the present invention. As can be seen from Table 4, the gamma nucleus, which was 2.94E-01 Bq / g after the first filtering, was reduced to 6.23E-03 Bq / g through the second filtering process after adding the flocculant, and the DF value was 47.2. Very high, all nuclides except Sb-124 and Cs-137 were removed below MDA.

6) After the second filtering ion adsorption step (S7) to remove the untreated radioactive material in the filtrate,

According to the present invention, the effective removal of Cs-137 and Sb-124 requires an ion exchange process capable of selectively removing the above-mentioned ions.

In the ion exchange column 204, mainly Cs-137 and Sb-124 nuclides are removed, and the ion exchange media used in the present process is preferably a metal oxide type.

7) the radiation concentration evaluation step (S8) and the concentrate storage step (S9) of the PVA solution from which the radioactive material is removed,

The radioactive material contained in the PVA solution is subjected to various decontamination processes from the collection / classification step (S1) of the PVA protective article (S1) to the ionic nucleus removal step (S7).

The final concentrate generated in this process is passed through the radiation concentration evaluation step (S8), and if the concentrate is below the MDA value, the concentrate is transferred to the concentrate storage step (S9). The radioactive material removal process can be performed to finally obtain a non-radioactive PVA concentrate.

In addition, it is possible to treat the concentrated liquid that has undergone the concentrated liquid storage step (S9) using a self-disposal step and a concentrated liquid drying and disposal step.

8) The disposal step (S10) of consigning the concentrated non-radioactive PVA solution to a specialized incineration company for alienation,

The concentrated PVA solution transferred to the concentrate storage step (S9) through the radiation concentration evaluation step (S8) is classified as a non-radioactive material and subjected to a disposal step (S10), and the disposal step (S10) is a self-disposal method. According to the self-disposal method (S10-1) for self-disposal of PVA solution concentrated at 35w / v% and the self-disposal of dry matter (S10-2a, S10- 2b) can be classified and used selectively.

A detailed example of the self disposal cost analysis according to the concentration rate of the PVA solution to be disposed of is shown in FIG. 7. When disposing the 35 ~ 45w / v% PVA solution presented in the present invention, it is expected that the disposal cost of about 13.6 ~ 10.9 million won. On the other hand, when it is completely dried at 85 to 100 w / v%, a relatively low disposal cost of 5.6 to 4.8 million won may be required.

In addition to the protective article decontamination method made of the water-soluble material of the present invention made of the above steps, the present invention provides a radioactive material decontamination apparatus used in the decontamination method.

This can maximize the cost and use efficiency of protective supplies by decontaminating water-soluble protective supplies, including protective products of PVA material generated from nuclear power plants.

The present invention is not limited by the embodiments described above, and various changes and modifications can be made by those skilled in the art, which are included in the spirit and scope of the present invention as defined in the appended claims.

1 is a block diagram showing a protective article decontamination method made of the polyvinyl alcohol of the present invention.

Figure 2 is a process chart showing a protective article decontamination method made of polyvinyl alcohol of the present invention.

FIG. 3 is a perspective view illustrating a multi reactor illustrated in FIG. 2. FIG.

4 is a cross-sectional view showing the multi reactor shown in FIG.

FIG. 5 is a plan view illustrating a multi reactor illustrated in FIG. 3. FIG.

Figure 6 is a process chart showing a state in which the flocculation process is separated in the protective article decontamination method made of polyvinyl alcohol of the present invention.

Figure 7 is a graph showing the relationship between the concentration of PVA solution treated by the present invention and the self-disposal cost.

Claims (22)

1) collecting / separating used PVA protective article; 2) a first washing step of pre-treating PVA protective article through ultrasonic cleaning under vacuum conditions; 3) dissolving / concentrating the PVA to secondary wash the protective article vacuumed by the primary wash step; 4) a primary filtering step of filtering the radioactive material present in the dissolved / condensed aqueous solution using a filter; 5) introducing a flocculant to treat the radioactive material in the untreated filtrate in the primary filtering and filtering the secondary; 6) ion adsorption step of removing radioactive material in untreated filtrate after secondary filtering; 7) evaluating the radiation concentration of the PVA solution from which the radioactive material has been removed and storing the concentrate; 8) Disposal step of treating the concentrated non-radioactive PVA solution; protective article disposal method made of polyvinyl alcohol comprising a. The method of claim 1, Step 2) is a method of disposing protective article made of polyvinyl alcohol, characterized in that to remove the beta nuclide is attached to or absorbed by the water-soluble protective article. The method of claim 2, The beta nuclide is a method of disposing protective articles made of polyvinyl alcohol, characterized in that H-3 and C-14. The method of claim 2, In the step 2), the protective article made of a polyvinyl alcohol, characterized in that the interior of the multi-reactor in a vacuum atmosphere of 100 ~ 300 Torr to increase the washing efficiency of the radioactive material attached or absorbed in the water-soluble protective article Disposal Method. The method of claim 4, wherein And the water-soluble protective article in step 2) is cleaned by a piezo-type ultrasonic generator in a vacuum atmosphere. The method of claim 4, wherein In the multi-reactor, the filtrate circulation line is located in a tangential direction on the outer circumferential surface so that the filtrate is introduced in a tangential direction to flow into the protective article made of polyvinyl alcohol. The method of claim 4, wherein And a heater tank for heating the inside of the multi-reactor in the step of dissolving / concentrating PVA to the multi-reactor. The method of claim 7, wherein The heater tank is a method of disposing protective article made of polyvinyl alcohol, characterized in that the primary dissolution to heat the multi-reactor to contain 5 to 15% by weight of the PVA of the water-soluble protective article in the solution therein. The method of claim 8, The method of disposing the protective article made of polyvinyl alcohol, characterized in that the solution in which the PVA is dissolved is concentrated to 35 to 45% by weight to minimize the amount of liquid waste to be disposed of. The method of claim 8, The heater tank is a method of disposing protective articles made of polyvinyl alcohol, characterized in that the pure water from which the ionic particles are removed to indirectly heat the multi-reactor by the heating jacket. The method of claim 10, The pure water accommodated in the heater tank is a method of disposing protective goods made of polyvinyl alcohol, characterized in that the heater is formed by the steam of 100 ~ 130 ℃. The method of claim 10, In the multi-reactor, the method of disposing protective goods made of polyvinyl alcohol, characterized in that to promote the dissolution of PVA with hydroxyl radicals generated by introducing hydrogen peroxide and iron salt to induce Fenton reaction during the first dissolution of PVA. The method of claim 12, In the multi-reactor, the protective article disposal method of polyvinyl alcohol, characterized in that to induce the Fenton reaction by injecting hydrogen peroxide and iron salt solution when the PVA material is 70-95% dissolved when the PVA is first dissolved. The method of claim 13, The hydrogen peroxide is injected into 0.3 ~ 1L _H2O2 / kg _{PVA protective suit} of 35% by weight purity, iron salt solution is 0.1 ~ 0.5L _{iron salt solution} / kg _{PVA protective clothing} disposal of protective articles made of polyvinyl alcohol, characterized in that Way. The method of claim 14, The iron salt solution was prepared by polyvinyl alcohol, which was formed by adding 6.25 mL of H 2 SO 4 (purity: 35%) and 2.18 g of FeSO 47 H 2 O in a 500 mL bolometric flask to a volume of 500 mL with distilled water, followed by purification for 1 hour. How to dispose of protective equipment. The method of claim 9, The solution in which the PVA is dissolved is evaporated by evaporating water by heating and decompressing in a temperature range of 80 to 85 ° C. and a pressure range of 100 to 300 Torr, and condensing the evaporated water to recycle the process water. Disposal of protective articles made of alcohol. The method of claim 1, The first filtering step is to remove the radionuclides contained in the concentrate using a filter having a diameter of 1 ~ 80㎛ primary protective article disposal method made of polyvinyl alcohol. The method of claim 17, After the first filtering step, the flocculant introduced through the flocculant injection / stirring step is used simultaneously with the acrylamide-based cationic / anionic polymer flocculant under the conditions of pH 6.5 to 7.0, and the dose is 0.2 to 1.0 mL _polymer. A method of disposing protective articles made of polyvinyl alcohol, characterized by removing gamma nuclides from the wastewater by falling into the / L _{PVA solution} range. The method of claim 18, The injected flocculant increases the decontamination efficiency by injecting coagulant nuclei containing iron salt in a 0.2 to 1.0 mL _{coagulant nucleus} / L _{PVA solution} ratio so that a stable floc can be produced in a PVA solution containing a high concentration of organic matter. Disposal method of protective articles made of polyvinyl alcohol, characterized in that. The method of claim 1, The first filtering step and the second filtering step is a method for disposing protective goods made of polyvinyl alcohol, characterized in that to filter the flocculant in the concentrate using a filter having a diameter of 0.2 ~ 80㎛. The method of claim 1, The ion adsorption step is a method for disposing protective articles made of polyvinyl alcohol, characterized in that the ion exchange media used for removing ionic nuclides in the form of metal oxides. The method of claim 1, Disposing step of treating the PVA solution is a method for disposing of protective articles made of polyvinyl alcohol, characterized in that is made by any one selected from the method of self-disposal of the concentrate concentrate or incineration of the concentrate dry matter.

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