JP6015062B2 - Equipment for concentrating radioactive material-containing water using a zeolite membrane - Google Patents

Description

  The present invention relates to a treatment method and apparatus for radioactive substance-containing water, and more specifically, waste water containing radioactive substance and the like using a zeolite membrane having water resistance, acid resistance, alkali resistance, heat resistance, and radiation resistance. Process, equipment and process for concentrating the radioactive material, and cooling of water containing high-temperature radioactive material etc. using a zeolite membrane The present invention relates to a process and an apparatus for obtaining and collecting decontaminated / purified water that substantially maintains a constant temperature and substantially does not contain the radioactive substance.

  Regarding the treatment of aqueous solutions containing radioactive substances generated at nuclear power plants, etc., ion exchange substances such as ion exchange resins, zeolite substances such as mordenite, clay substances such as smite, and other various adsorbents Proposal or practical use include a method for adsorbing and removing radioactive materials, a method in which a radioactive substance is directly coagulated, precipitated or floated by adding a flocculant, or a radioactive substance is coprecipitated or adsorbed with a substance that is coagulated, precipitated or floated together (Non-Patent Document 1).

We also propose or put into practical use a method for concentrating the radioactive substance by pressure filtration of an aqueous solution containing the radioactive substance through a polymer reverse osmosis membrane, etc., and collecting purified water that does not contain the radioactive substance. Has been.
Any of these methods is a treatment method that is quite effective for an aqueous solution in which the main component of the soluble substance is a radioactive substance and its content is relatively small. However, coexistence is required when treating radioactive material-containing aqueous solutions that contain a large amount of substances other than radioactive substances, such as highly radioactive wastewater containing seawater, etc., generated by the tsunami disaster at the Fukushima Daiichi Nuclear Power Station. The presence of substances impedes the adsorption effect, etc., significantly reducing the removal efficiency of the radioactive substances, and it is substantially impossible to acquire and recover purified water that contains almost no dissolved substances as well as radioactive substances. It is quite difficult.

For this reason, in the treatment of radioactive wastewater generated in large quantities by the accident at the time of the tsunami at the Fukushima Daiichi Nuclear Power Station, the radioactive material is first removed or reduced by the adsorption method or the coagulation sedimentation method. A hybrid process is separately employed which is separately removed and concentrated in a reverse osmosis process using slag (Non-Patent Document 2).
However, because the osmotic pressure of the wastewater at the Fukushima Daiichi Nuclear Power Station containing coexisting substances close to seawater concentration is high, the reverse osmosis (RO) process, which requires more than the osmotic pressure, permeates the membrane. In principle, it is difficult to obtain and recover the purified water at a high recovery rate and to concentrate dissolved substances that do not permeate the membrane at a high magnification. Incidentally, since the osmotic pressure of seawater is about 2.5 MPa and the operating pressure of the reverse osmosis method is usually about 5 to 6 MPa, the water recovery rate in such a case can be expected to be only about 50%. In other words, the concentration factor of the dissolved substance that does not permeate the membrane is 2 times or less.

Furthermore, when the adsorption method is used, a decrease in adsorption efficiency due to the presence of coexisting substances increases the amount of adsorbent used. In addition, reverse osmosis membranes are currently only made of polymers, and as the radiation dose increases due to concentration, etc., the degradation of the polymer membrane becomes more severe and its consumption increases. The amount generated will increase considerably.
As a membrane separation process other than the reverse osmosis method, several apparatuses and processes using a membrane distillation method and a pervaporation method have been proposed. Membrane distillation is a process that permeates water vapor using a hydrophobic polymer porous membrane that keeps the gas phase without penetrating a liquid aqueous solution into the pores in the membrane. It is a process that is similar in form to the pervaporation method utilized in the present invention, such as the difference in water vapor pressure, while the pervaporation membrane has a separation function in the molecular order of water and ethanol, The pore size of the hydrophobic porous membrane used in the membrane distillation method is as large as at least 0.1 micrometer (μm) or more, and there is no separation function for such an evaporated component. However, there are some proposals such as Patent Document 1 and Patent Document 2 regarding application to concentration of radioactive substance-containing water. In any case, since a hydrophobic polymer porous membrane is used, it is difficult to expect high radiation resistance, and there is a limit to application to treatment of aqueous solutions containing radioactive substances at high temperatures and high radiation doses. Moreover, in reality, it is difficult to maintain the hydrophobicity of the membrane due to membrane contamination due to hydrophilic substances, etc., and it is difficult to maintain the membrane distillation action for a long time, which allows only water vapor to permeate through the membrane. At present, practical membrane distillation membranes that can maintain the hydrophobicity of the membrane for a long time have not yet been developed for both polymers and ceramics.

  As with the present invention, there are also proposals such as Patent Document 3 and Patent Document 4 regarding application of the pervaporation method using a hydrophilic inorganic porous membrane that is expected to have high radiation resistance. Patent Document 3 proposes an apparatus structure for separating and removing moisture from radioactive waste such as radioactive sludge using a hydrophilic inorganic porous membrane having a pore diameter of about 20 mm (2 nm). However, there is no description regarding a specific application method relating to removal of coexisting fine particles, collection of membrane permeated water vapor, and the like. The pervaporation membrane used is not particularly specified, but in the examples, an alumina sol thin film is applied to the surface of a porous alumina substrate having a pore diameter of about 2 μm to form a porous layer having a pore diameter of about 20 mm (2 nm). An all-alumina hydrophilic porous membrane is used. Although there is no particular description about the firing of the sol layer, it is difficult to apply to a radioactive aqueous solution that is chemically unstable and high temperature without firing, and if it is fired, the hydrophilicity decreases and the water vapor transmission performance is considerable. Lower.

  Patent Document 4 is a proposal that specifies that microfiltration is performed using a hollow fiber membrane filter or a hydrophobic porous membrane as a pre-filter for the purpose of concentrating radioactive waste liquid with a pervaporation membrane and suppressing the blockage of the membrane. The separation membrane used is not particularly specified, but in the examples, the use of a polymer non-porous pervaporation membrane and the use of a polymer hollow fiber filter as a prefilter is described, both of which are polymer membranes For this reason, it is difficult to apply to high temperature radioactive substance-containing water at 100 ° C. Moreover, there is no description about the hydrophobic porous membrane for microfiltration other than the hydrophobic polymer porous membrane used in the membrane distillation.

Japanese Patent Publication No. 3-8800 Japanese Patent Laid-Open No. 3-68434 Japanese Patent Laid-Open No. 2-82199 JP-A-2-120698

The Japan Nuclear Industry Council "Radioactive Waste Guidebook 1994 Edition" (July 1994) TEPCO Fukushima Daiichi Nuclear Power Station, Road to Convergence of Accident, Step 2 Completion Report (December 16, 2011, Nuclear Disaster Response Headquarters, Government / Tokyo Electric Power Integration Office)

In the treatment of wastewater containing radioactive materials, it is possible to effectively separate the radioactive materials and coexisting materials from each other, collect as much purified water from which these soluble materials have been removed as possible, and concentrate the radioactive materials as much as possible. It is required that the volume and weight of concentrated water and radioactive final waste generated by processing be as small as possible. In addition, in the event of an accident at a nuclear power plant where the existing cooling system is difficult to use, efficient cooling of high-temperature radioactive material-containing water and nuclear fuel pool water where heat generation due to residual radioactive material in the nuclear fuel becomes a problem Efficient constant temperature maintenance is required.

As a result of various studies to achieve the above object, the present inventors have found that the above problems can be solved by the following apparatus, and have completed the present invention.
That is, the gist of the present invention is as follows.
(1) A membrane separation device for concentrating cesium-containing water, a metal or ceramic microfiltration device for separating and removing fine particles from cesium-containing water, and supplying cesium-containing water from which fine particles have been removed to a membrane module For removing the water from the cesium-containing water by an osmotic vaporization process and concentrating the cesium, and comprising a chabazite-type zeolite membrane containing a zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 3 or more A membrane separation device for concentrating cesium-containing water, comprising a module and a device for collecting and collecting membrane-permeated water vapor that has passed through the zeolite membrane.
(2) microfiltration device is made of metal, and having a function capable of separating and removing 30μm or more fine particles (1) Symbol placement of the device.
(3) The apparatus according to any one of (1) and (2) , which is equipped with a heating device for heating the water to be treated before reaching the membrane module.
(4) The apparatus according to any one of (1) to (3) , which includes a metal concentrated water tank having radiation resistance and a metal or plastic purified water tank.
(5) Equipped with piping for recirculating and supplying treated water concentrated with zeolite membrane as treated water, and a control valve for adjusting the return amount thereof (1) to (4) The apparatus of any one of Claims.
(6) The apparatus according to any one of (1) to (5) , which is equipped with an ejector device that sucks and collects water vapor that has passed through the zeolite membrane and has been decontaminated and purified.
(7) The apparatus according to (6), wherein the aqueous solution discharged from the ejector is reused as working water for the ejector.
(8) In order to keep the working water vapor pressure of the ejector used for sucking and collecting the membrane permeating water vapor low, a cooling device for cooling the working water of the ejector is provided.
The device according to (6) or (7) .
(9) The apparatus according to any one of (1) to (8) , wherein the apparatus is equipped with a device for removing radioactive substances by an adsorption method, an agglutination method, or a dialysis method alone or a combination of a plurality of methods for the purpose of suppressing a high radiation dose of the treatment system. The apparatus of any one of Claims.
(10) The device according to any one of (1) to (9) , wherein the zeolite membrane is a zeolite membrane formed on an inorganic porous support.
(11) A method for concentrating cesium-containing water, wherein cesium-containing water is supplied to a membrane module including a chabazite-type zeolite membrane containing zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 3 or more, and pervaporation A method for concentrating cesium-containing water, comprising removing water from the cesium-containing water by a process and concentrating cesium.
(12) The method for concentrating cesium-containing water according to (11) , wherein the zeolite membrane is a zeolite membrane formed on an inorganic porous support.

Therefore, the present invention utilizes the pervaporation (PV) separation function possessed by a ceramic zeolite membrane excellent in hot water, acid resistance, alkali resistance, and radiation resistance that exhibits a stable separation function even at a high temperature of 100 ° C. or higher. To obtain and recover purified water substantially free of radioactive substances and coexisting substances contained in non-treated water to be treated at a high recovery rate, and to highly concentrate the radioactive substances and coexisting substances And provide a process.
In addition, by utilizing the latent heat transfer action in the pervaporation and separation function of the zeolite membrane, it is possible to efficiently reduce the temperature of the high-temperature radioactive material-containing water, maintain the cooling of the fuel pool water that stores the spent nuclear fuel, etc. Devices and processes that can be performed automatically.

Principle diagram of pervaporation process with zeolite membrane Permeation and separation mechanisms in zeolite membranes Basic configuration of pervaporation process for treating radioactive material-containing water with the zeolite membrane of the present invention and collecting decontaminated / purified water Specific example of the radioactive substance-containing water treatment process of the present invention Schematic of the equipment used for the pervaporation method of the example

  As mentioned above, regarding the treatment of water used to operate nuclear power plant reactors and radioactive material-containing wastewater generated by accidents at nuclear facilities, etc. It is required that the purified water from which coexisting substances have been removed to a level that can be discharged to the outside can be obtained and recovered at the highest possible recovery rate, and at the same time, the weight of radioactive waste generated by these treatments The capacity is ultimately required to be as small as possible.

  As described in the above-mentioned technical background, alkaline earth metal salts such as strontium (Sr), cobalt (Co), etc. are used as treatment methods for waste water containing soluble radioactive materials that have been implemented or proposed to date. Dissolved radioactive materials such as heavy metal salts are mainly produced by the coagulation precipitation method, and dissolved radioactive materials such as alkali metal salts such as cesium (Cs) and halogen compounds such as iodine (I) are mainly produced by the adsorption method, and non-soluble materials such as sodium chloride (NaCl). Radioactive dissolved salts are separated and removed using an ion exchange resin or a reverse osmosis (RO) membrane, and purified water is recovered.

However, when processing highly radioactive wastewater containing a large amount of radioactive material, it is easy to capture the radioactive material by coagulation sedimentation or adsorption methods, but these methods are used when the radioactive material is treated water at a relatively low concentration. Therefore, it is desirable to remove by applying these methods after increasing the concentration to some extent to increase the processing efficiency.
In many cases, a reverse osmosis (RO) membrane is usually used for concentration of an aqueous solution containing a low-concentration dissolved substance that does not contain radioactive substances. However, even when the radioactive material concentrates the water to be treated at a relatively low concentration, the reverse osmosis (RO) membrane made of a polymer and its sealing material deteriorate due to the radiation dose of the concentrated radioactive material. It is difficult to concentrate using (RO) membrane, and there is no other suitable concentration method so far.

  Currently, all commercially available reverse osmosis (RO) membranes are polymer membranes, and inorganic membranes with high radiation resistance have not yet been developed. In addition, as described above, even if the radioactive material of the water to be treated is low in concentration, if it contains seawater and other non-radioactive salts in a large amount as in the Fukushima Daiichi Nuclear Power Plant accident, it will penetrate by concentration. As the pressure increases and the effective pressure difference that becomes the driving force for water to permeate through the membrane is reduced, the reverse osmosis (RO) membrane can only concentrate at most twice. For this reason, in the accident at the time of the tsunami disaster at the Fukushima Daiichi Nuclear Power Station, a large amount of concentrated RO water was generated, and it was unavoidable to add more storage tanks one after another. (Refer nonpatent literature 2).

As described above, as a membrane separation process other than the reverse osmosis method, application of a membrane distillation method or a pervaporation method has been proposed. However, with regard to the membrane distillation method, there is substantially no membrane that can be applied other than the hydrophobic polymer porous membrane at present, and high-temperature radioactive material-containing water having a temperature of 100 ° C. or higher, such as nuclear power plant wastewater generated at the time of disaster Application to processing is difficult. With regard to the pervaporation method, a practical pervaporation membrane that is chemically stable in water resistance, acidity, alkali resistance, etc. even at high temperatures and exhibits high water vapor permeability and can be used industrially has not been developed yet. No such membrane application has been reported yet. Incidentally, polymers are generally weak against alkaline solutions, and there are few polymers that can withstand high-temperature alkaline aqueous solutions other than fluororesins. Although the hydrophobic polymer porous membrane is made of a fluororesin, it is not a bulk material made of so-called Teflon (registered trademark), so that the hydrophobic property of the porous portion is hydrophilic in a high-temperature alkaline aqueous solution. Its function is greatly altered, such as becoming hydrophilic.

Under such circumstances, the present invention is effective in treating water to be treated, such as radioactive waste water, in which radioactive substances of relatively low or medium concentration are dissolved, even if other dissolved salts coexist. An object of the present invention is to provide a method for obtaining and recovering water with a high recovery rate that is well concentrated and purified to such an extent that it contains substantially no radioactive substances or dissolved salts and can be discharged.
Furthermore, in order to reduce the temperature of high-temperature treated water containing radioactive substances, at present, in addition to the conventional method of lowering the temperature with cooling water using an indirect heat exchanger that does not make direct contact with the cooling medium. The fact is that there is no appropriate method. However, when cooling with such an indirect heat exchanger, especially in cases where the water to be treated is hot or large in volume, a heat exchanger with a large heat transfer area and a large equipment size and a large amount of cooling water are used. A large pump that feeds the liquid is required.
Therefore, the present invention efficiently reduces the temperature of high-temperature radioactive substance-containing water by using a latent heat transfer action in the pervaporation / separation (PV) function of the heat-resistant / radiation-resistant zeolite membrane. It is intended to provide a novel cooling method that can be used.

(Permeate vaporization (PV) process)
The pervaporation (PV) process, which is the core of the present invention, is a relatively new technology as a membrane separation process based on the principle shown in FIG. It has been put to practical use in the field of dehydration of used isopropyl alcohol (IPA).
In this pervaporation process, as shown in FIG. 1, the water to be treated is supplied to the primary side of the membrane (the water to be treated). Since it selectively permeates and desorbs from the secondary surface of the membrane in the form of water vapor, it is collected and condensed to obtain membrane permeate. On the other hand, a part of the water to be treated is concentrated as a result of permeation through the membrane and discharged from the outlet of the membrane device. The driving force of the membrane permeation is a vapor pressure difference of water which is a membrane permeable substance.

Note that the vapor permeation (VP) process supplies not the liquid to the primary side of the film but the vapor obtained by completely evaporating the liquid to be treated. Currently, bioethanol concentrated to about 90 wt% by distillation is put to practical use in a process of dehydrating and concentrating to 99.5 wt% or more using the A-type zeolite membrane having the highest hydrophilicity.
FIG. 2 shows the concept of the membrane permeation mechanism in the zeolite membrane. Zeolite is alumina (Al
₂ O ₃ ) and silica (SiO ₂ ) mixed crystal, depending on the bonding method, 3 to 8% (0.3
Since fine crystal holes of about 0.8 nm) are formed, water moves through the holes and permeates the membrane. In a hydrophilic zeolite membrane, water molecules with a diameter of about 3 mm (0.3 nm) are vaporized at the zeolite pore inlet on the membrane surface and are selectively taken into the pores, and further permeate through the zeolite pores by diffusion. . The driving force for the incorporation of water molecules into the zeolite pores by vaporization and the subsequent diffusion in the pores is a chemical potential difference based on the water vapor pressure difference. Also, the zeolite pores that have taken in water molecules are slightly larger than water molecules in terms of size, but are not so different from each other, so they are clogged with water molecules, so other molecules such as radioactive substances or It is estimated that separation of water and substances dissolved in the water to be treated occurs when there is no room for ions or the like to enter. As described above, since the size of the zeolite pores is in the molecular order, if the molecular size (ion size) of the dissolved substance is larger than the water molecule, naturally the separation action by the sieving effect contributes.

It is a well-known fact that the pervaporation (PV) process using a zeolite membrane that exhibits such a separation function can be used for dehydration concentration to remove water from a relatively high concentration aqueous alcohol solution. It's being used. However, in general, zeolite has higher chemical stability such as acid resistance as the SiO ₂ / Al ₂ O ₃ molar ratio increases. However, the A-type zeolite membrane currently in practical use has a small molar ratio of 1 and is substantially reduced. Since there is almost no water resistance and the crystal structure of the film is destroyed over time in hot water, it is practically difficult to apply organic solvents with a water content of about 20% or less for purposes other than dehydration. However, there are no reports of industrial application in the water treatment field.

Therefore, the present inventors have a large SiO ₂ / Al ₂ O ₃ molar ratio of 3 or more, which is far superior to conventional zeolite membranes in water resistance, heat resistance, acid resistance, radiation resistance, etc., but is hydrophilic. T-zeolite that has high water vapor permeability comparable to that of A-type zeolite membranes with high water vapor permeability and that exhibits stable separation performance without destroying the membrane structure even in high-temperature hot water at 100 ° C or higher Membranes and new chabazite-type zeolite membranes have been developed, making it possible to use them in the water treatment field. Furthermore, using such a highly functional zeolite membrane, the aqueous solution containing the radioactive substance is treated water, the water is separated from the radioactive substance and the coexisting soluble substance, and the purified water is recovered at a high recovery rate. In addition, the inventors have intensively developed a method capable of concentrating the radioactive substance at a high magnification that cannot be obtained by the conventional reverse osmosis (RO) process, and invented the process and apparatus.

  Further, in the pervaporation (PV) process, a phase change occurs across the membrane, so that the latent heat is also thermally transferred as the membrane permeates, resulting in a decrease in the temperature of the water to be treated. This temperature drop is particularly large in the case of water having a large membrane permeation component, and 2% equivalent of the water to be treated permeates through the membrane. A temperature drop of about 50 ° C. can be achieved by passing through the membrane.

Therefore, the present inventors have studied in detail how to use this phenomenon as a method for cooling hot water in nuclear power generation facilities and the like, and have invented the process and apparatus.
As already mentioned, the only membrane separation method that can be used for the same purpose as the present invention is currently only a reverse osmosis (RO) process, but currently there are only polymer membranes with poor radiation resistance. Therefore, it is difficult to use it for the purpose of highly concentrated radioactive materials. In particular, in a system where a large amount of dissolved substances coexist with radioactive substances in the water to be treated, there is a problem of osmotic pressure as described above, so it is theoretically difficult to concentrate the coexisting substances together with the radioactive substances at a high concentration. It is.

  However, in the pervaporation (PV) process used as the core technology in the present invention, a high-performance zeolite membrane having water resistance, heat resistance, hot water resistance, radiation resistance and high separation performance is used, and the driving force for membrane permeation Since the water vapor pressure difference is used, the water pressure difference required for the water permeation of the water can be easily secured by increasing the temperature of the water to be treated as much as necessary even if the concentration progresses. There is no concentration limit based on osmotic pressure as in the reverse osmosis process with the driving force, and it is possible to concentrate almost to the solubility limit of dissolved substances.

In the case of a hydrophilic zeolite pervaporation membrane having an average pore diameter of 10 mm (0.1 nm) or less, as described above, selective incorporation of water into the zeolite pores and the effect of eliminating other molecules resulting therefrom, as well as water and others. Since the advanced separation function due to the sieving effect due to the difference in molecular size from the solute of the solute is expressed, the obtained water is highly purified to the extent that there is substantially no dissolved substance.

In addition, since water molecules that have permeated the membrane leave the membrane as water vapor on the secondary side (permeation side) surface on the back side of the membrane, the membrane permeated water collected and condensed is in the form of ions or salts. It is considered that it is difficult in principle to mix radioactive substances such as cesium (Cs131 and Cs137) which are considered to be dissolved in the water to be treated, and it is highly purified.
In addition, since the driving force of membrane permeation in the pervaporation process is a difference in vapor pressure, and it is necessary to supply latent heat of vaporization for water membrane permeation, it is concentrated by evaporation and the condensed water of the generated vapor is recovered as purified water. Some point out that it is basically the same as the usual evaporation method. However, the following permeation vaporization process has the following advantages with respect to treatment with an aqueous solution system containing at least a radioactive substance to be treated by the present invention.

  First, regarding the heat source to be used, a processing target that is generally used under atmospheric pressure is usually operated at 100 ° C. or higher in the evaporation method of an aqueous solution. Therefore, a high-quality heat source at least about 120 ° C. or higher is required. However, in the pervaporation process, since the driving force of membrane permeation is a vapor pressure difference, heating at 100 ° C. or higher is not necessarily required in principle, and actually it is usually operated at about 40 to 80 ° C., As the heat source, a low-quality heat source such as waste heat of 100 ° C. or less can be used.

  Next, in the pervaporation process, water molecules are considered to evaporate at the entrance of the crystal pores of the zeolite membrane due to the presence of interfacial tension. From the selectivity, only water molecules evaporate by being separated from radioactive substances. Moreover, the water to be treated is always maintained in the liquid phase until the treatment is completed, and even when heating is necessary to increase the water vapor pressure, the liquid phase does not create a space for the vapor phase in a form confined in a closed system. It is in a state.

On the other hand, in the evaporation method, water and the like are evaporated in a state where the separation action does not work and the selectivity does not function in a system containing dissolved substances, so volatile substances such as cesium (Cs) system and iodine (I) system are used. Radioactive materials will also move to the vapor side. In addition, these radioactive vapors are generally different in condensation temperature from water and are not guaranteed to condense together with water, and in order to avoid external leakage of the radioactive vapors, it is possible to adsorb and remove gaseous radioactive substances. It is necessary to equip equipment separately, and this leads to increase of the final radioactive waste.

  Furthermore, in the osmotic vaporization process for cooling of the present invention, which is utilized for cooling high-temperature hot water containing a radioactive substance by utilizing the moving action of latent heat of evaporation accompanying the permeation of water in the osmotic vaporization process, the membrane is substantially Can be considered as a heat exchanger serving as a heat transfer surface, and since the heat exchange is performed in the form of latent heat of vaporization, the heat exchange device is extremely efficient. That is, as compared with a normal shell and tube type indirect heat exchanger that exchanges the same amount of heat, the cooling pervaporation device of the present invention using latent heat transfer has a compact size of at least 1/5 or less in its volume. It becomes a device.

  In addition, shell-and-tube type indirect heat exchangers that perform sensible heat exchange require a large amount of cooling water approximately 10 times more than the heat exchange method of the present invention, and provide cooling water (facility) that can cope with that. Pump power nearly 10 times is required. The fact that the required amount of cooling water is substantially 1/10 less than the conventional cooling system that uses a normal indirect heat exchanger is a backup in the event of a trouble such as that at the Fukushima Daiichi Nuclear Power Station. This is a great advantage when used as a system. Furthermore, since the membrane permeated water that flows out as a result of this cooling is highly purified as described above, it can be discharged to the outside without any special treatment.

The proponents of the present invention have intensively conducted technical development for many years, such as the development of zeolite membranes and their application to bioethanol dehydration concentration. And the present inventors came to grasp the membrane permeation mechanism and phenomenon of the above-mentioned zeolite pervaporation membrane specifically and in detail, and developed a high separation performance with newly developed hot water resistance and radiation resistance. Using a high-performance zeolite membrane, it is possible to efficiently decontaminate the water to be treated containing radioactive substances generated at nuclear facilities, etc., and to concentrate the radioactive substances efficiently, and at the same time, high temperature containing radioactive substances etc. The inventors have invented a process and apparatus that can efficiently cool the hot water.
Specific embodiments and the like will be described in detail below.

(Basic configuration of equipment and process)
FIG. 3 shows an outline of the pervaporation (PV) apparatus and process for the treatment of radioactive substance-containing water of the present invention. The apparatus and process include a membrane module equipped with a highly functional zeolite separation membrane having acid resistance, hot water resistance, radiation resistance and high separation performance inside, a liquid feed pump for supplying treated water to the membrane module, a membrane A heat exchanger for collecting and condensing water vapor that has passed through the zeolite membrane in the module and a vacuum pump for maintaining the permeation side of the membrane module in a reduced pressure state are the minimum components, but especially pollutants In the equipment and process for the purpose of concentrating radioactive water containing radioactive materials containing selenium, the membrane separation function deteriorates due to so-called membrane contamination, where the surface of the zeolite membrane is contaminated by the deposition of coexisting fine particles. It is equipped with a microfiltration device that captures and removes fine particles in the treated water to be supplied in advance.

(Zeolite membrane)
The zeolite pervaporation membrane used in the water treatment process of the present invention is excellent in water resistance, heat resistance, acid resistance, alkali resistance, radiation resistance, high water vapor and high permeability, and stable separation performance even at a high temperature of 100 ° C or higher. It is essential to show. Therefore, it is difficult to use a conventional ceramic pervaporation membrane having a chemical stability problem such as an all-alumina porous membrane formed from an A-type zeolite membrane or alumina sol, or a silica-based porous membrane. Therefore, in the present invention, a zeolite having a water / heat resistant / acid resistant / alkali resistant / radiation resistant high water vapor high permeability performance and a SiO ₂ / Al ₂ O ₃ molar ratio of at least 3 or more, preferably 5 or more. Is a zeolite membrane containing as a main component. The average pore diameter is preferably 10 mm (1 nm) or less. More specifically, it is desirable to use T-type zeolite membrane, chabasite-type zeolite membrane, MFI-type zeolite membrane, FAU-type zeolite membrane, MOR-type zeolite membrane, and carbon membrane. From the viewpoint of permeability, it is preferable to use a T-type zeolite membrane or a chabazite-type zeolite membrane. Each of these zeolite membranes is a layer of the zeolite membrane formed on the surface of an alumina porous body or the like, and the zeolite pore diameter is 8 mm (0.8 nm) or less. Note that the chabasite type (CHA type) zeolite membrane described in JP2011-121040 is preferable.

(Microfiltration device)
As described above, the present invention is equipped with a microfiltration device.
However, in conventional reverse osmosis processes, polymer filters and polymer microfiltration membranes (MF) are often used for this purpose. However, high-temperature wastewater containing radioactive materials and the like are covered. In the process of the present invention, which is often treated water, heat resistance and radiation resistance are indispensable properties, so ceramic or metal made by sintering inorganic oxide or metal powder such as alumina. It is desirable to use a porous filter. In particular, metal filters that use fine gaps between wires formed by twisting and winding metal wires around a metal support, and fine mesh-like fibers by compression molding thin metal fibers It is preferable to use an all-metal microfiltration device using a metal filter or the like that uses a gap. This is because this type of all-metal filter has a low filtration resistance of water to be treated and can be backwashed very easily using a gas such as air or nitrogen. The metal filter is preferably at least 70 ° C. or higher, preferably 100 ° C. or higher, which can be used for the filtration of hot water. At least 30 μm or higher, preferably 10 μm or higher, particularly preferably 1 μm or higher fine particles are separated. It is preferable to use one having a performance that can be removed.

(Heating device for treated water)
In the treatment of aqueous solution containing radioactive substances by the pervaporation method, the treatment speed is proportional to the water vapor pressure difference given across the pervaporation membrane, so it is equipped with a heating device that preheats the water to be treated supplied to the membrane module The heating of the water to be treated is an extremely effective means for reducing the membrane area of the used pervaporation membrane, which is the dominant factor of the apparatus fixing cost. In particular, in the treatment of radioactively contaminated soil decontamination wastewater, since it is actually assumed to be implemented locally, the equipment of this heating device is indispensable.

(Storage tanks for concentrated water and membrane permeated water)
In the present invention, the installation of tanks for water to be treated, concentrated water, and membrane permeated water is not necessarily an essential condition. However, when treating substances containing aqueous solutions or radioactive materials that are estimated to contain radioactive substances by contact with radioactive materials, etc., prevention to prevent the outflow of radioactive substance containing water to other places as much as possible From the viewpoint of measures, it is desirable to install tanks for water to be treated, concentrated water, and membrane permeated water, all of which are preferably metal tanks having radiation resistance.

  However, the tank for water to be treated can be omitted when the pervaporation (PV) process of the present invention is provided in a line of a nuclear facility or the like. The membrane permeated water tank can be replaced with a tank made of reinforced plastic or the like because the membrane permeated water is purified by permeation of the zeolite membrane. However, although the membrane permeated water is discharged directly to the outside even though it is usually sufficiently purified, there is a concern about the leakage of radioactive materials when trouble occurs in the membrane module. It is desirable to install as many tanks as possible.

(Circulating and supplying treated water to the membrane module)
When the water to be treated is treated with a separation membrane as in the present invention, the supply of the water to be treated to the membrane module is basically completed in one pass and the membrane treatment is generally completed. Equipped with membrane area. When a large amount of water to be treated is generated on the production line, continuous treatment with one pass is necessary. However, in cases such as when treating radioactive material-containing wastewater, a predetermined amount of wastewater that already exists is treated for a predetermined time. In some cases, a certain amount of time is allowed for the processing time. In such a case, by performing a batch-type circulation process that returns the treated water that has undergone membrane treatment to the treated water tank, the membrane area can be reduced and the number of membrane modules used can be reduced compared to the case of one-pass continuous treatment. can do. In other words, the fixing cost of the membrane equipment can be saved at the expense of processing time. However, since it depends on the setting conditions, purpose, environmental conditions, etc., which one should be emphasized, it is actually necessary to optimize them.
As described above, in order to enable not only the one-pass treatment method but also the circulation treatment method, a pipe for returning the membrane-treated treated water to the treated water tank and a control valve capable of adjusting the return amount are equipped. It is preferable.

(Use of ejector)
In the pervaporation (PV) process that is the core technology for carrying out the present invention, most of the water in the water to be treated supplied to the membrane module is driven by the difference in water vapor pressure across the membrane in the membrane module as a driving force. It passes through the membrane and becomes water vapor on the back side of the zeolite membrane (the surface on the permeate side), and is led to a heat exchanger for condensation installed in front of a vacuum pump for maintaining the membrane permeate side under reduced pressure. Is done. The liquefied membrane permeated water is further guided to a gas-liquid separator located between the heat exchanger and the vacuum pump, and the liquid membrane permeated water stored in the lower part of the liquefied membrane permeated water is supplied to an external membrane via the pump. It is sent to the permeate tank.

  However, these membrane permeation equipment that collects and condenses “membrane permeation water vapor” that has permeated through the zeolite membrane and flows out through the gas-liquid separator can be replaced with an ejector. . The ejector is a tubular device with a circular cross section devised so that the middle part of the flow path becomes narrow, and when the working fluid flows at a high speed inside it, the venturi part that narrows the flow path uses the phenomenon of decompression This is a device that exhibits a vacuum pump function. In the permeation vaporization process used in the present invention, when the membrane permeation system device is replaced with this ejector, the heat exchanger for condensation, the gas-liquid separator, the vacuum pump for maintaining the reduced pressure, and the gas-liquid separator are used. All the five functions of the liquid pump can be replaced with one ejector, and the membrane permeation system can be remarkably simplified. In this case, the water vapor that has permeated through the membrane is directly guided to the inside of the venturi portion with a narrowed inner diameter provided in the middle portion of the ejector flow path through an external pipe, and is absorbed by the working water for the ejector. That is, the ejector can perform all of the functions of collecting the membrane permeation water vapor, maintaining the reduced pressure state on the membrane permeation side, condensing the membrane permeation water vapor, and feeding the liquefied membrane permeate water. Therefore, it is preferable to equip an ejector device for sucking and collecting water vapor that has passed through the zeolite membrane and has been decontaminated and purified.

(Reuse of membrane permeated water to ejector operation water)
As the working fluid of the ejector, “membrane permeated water” stored in the membrane permeated water tank can be used. In this case as well, the water vapor that has passed through the membrane is directly introduced into the venturi portion of the ejector through the external pipe and absorbed by the “membrane permeated water” used as the working water. Therefore, it is preferable to reuse the aqueous solution discharged from the ejector as working water for the ejector.

(Cooling water for ejector operation)
The suction operating pressure of the ejector is generally governed by the supply speed of the working water and the water vapor pressure. In particular, the water vapor pressure of the working water governs the lower limit of the suction working pressure inside the venturi section.
For this reason, as described above, when the membrane permeated water is reused for the ejector operating water, the concentration of the water to be treated by the membrane treatment advances as the circulation operation proceeds, and the ejector operating water is condensed by the heat of condensation of the membrane permeated water. The temperature gradually rises, and as a result, the suction operating pressure of the ejector is increased, thereby reducing the trapping ability of the membrane permeation water vapor and the processing capacity of the entire system.
Further, when the operation temperature of the water to be treated is not so high as about 40 to 60 ° C., it is necessary to lower the water vapor pressure on the membrane permeation side in order to increase the water vapor pressure difference of the membrane permeation. It is necessary to keep the temperature of the working water sufficiently low.

  Therefore, in order to cope with these situations, it is necessary to equip a cooling device for lowering the temperature of the ejector operating water. For cooling, water of relatively constant temperature existing in nature such as groundwater and seawater may be used as cooling water, and the temperature is lowered by using a cooling tower (cooling tower) that is often used in production factories and buildings. Ordinary cooling water produced may be used. In addition, when a cooling water having a temperature lower than that of these cooling waters is particularly necessary, a cooling liquid cooled using a heat pump type cooling device or the like may be used.

  As described above, in the treatment process using the zeolite pervaporation membrane of the present invention, the water vapor pressure on the membrane permeation side is an extremely important factor that affects the increase / decrease in the membrane permeation water. The temperature control of the ejector operation water that greatly affects the operation efficiency of the present invention can be used to easily control the concentration of the radioactive substance-containing water and the treatment effect of the entire treatment process for collecting the purified water, which is the object of the present invention. . Accordingly, it is preferable to provide a cooling device for cooling the working water for the ejector in order to keep the working water vapor pressure of the ejector used for sucking and collecting the membrane permeating water vapor low.

(Suppression of high radiation dose by concentration)
In the concentration process of radioactive substance-containing water using the zeolite pervaporation (PV) membrane of the present invention, it is possible to easily concentrate at a high concentration. It should be noted that the radiation dose is so high that no safe working environment can be maintained due to concentration.
In such a case, it is desirable to reduce the radiation dose of the water to be treated by using an adsorption method, a coagulation method, a dialysis method, or a combination of two or more of these. As an adsorbent in the adsorption method, ion exchange resin, zeolite, activated carbon, bentonite, smite, ferrocyanic compound, etc. can be used, but are not particularly limited to these, and not only the use of these adsorbents alone. Two or more types may be used in combination, or two or more types of adsorption methods using different adsorbents may be used in combination.

As the aggregating method, an agglomerating precipitation method or agglomerating flotation method by adding one or more of acid, alkali, aluminum compound, iron compound, acrylic type aggregating agent and the like are effective. Is not to be done.
As the dialysis method, a diffusion dialysis method or an electrodialysis method using a (strong / weak) cation exchange membrane, a (strong / weak) anion exchange membrane, a neutral dialysis membrane or the like as appropriate can be used.

  The treatment to reduce the radiation dose of the water to be treated by using these methods alone or in combination of two or more is performed during the concentration by the pervaporation process using the zeolite membrane or on the concentrated water after the concentration. However, when the radiation amount of the water to be treated is high from the beginning, it is preferable to perform the treatment on the water to be treated before the treatment water is supplied to the pervaporation process. Therefore, it is preferable to equip a device for removing radioactive substances by an adsorption method, an agglutination method, or a dialysis method alone or in combination with each other for the purpose of suppressing a high radiation dose of the treatment system.

(Concentration treatment of radioactive water)
As another gist of the present invention, it is preferable to perform concentration of radiation-containing water using the above-described apparatus.
(Treatment of decontaminated wastewater from radioactively contaminated soil)
The treatment process using the zeolite pervaporation (PV) membrane of the present invention is a radioactive cesium (C
s), radioactive strontium (Sr), radioactive iodine (I), etc., concentration of radioactive material-containing wastewater generated in the decontamination process of soil contaminated with radioactive materials, and recovery of purified water from which radioactive materials have been removed When applied for the purpose, extremely effective results are obtained.

  Contaminated soil contaminated with radioactive material and having radioactivity is considered to be attached, adsorbed or chemically bonded to the soil. For this reason, in order to decontaminate these contaminated soils, as in the case of decontamination of heavy metal-contaminated soils, first, an acidic or alkaline aqueous solution or the like that dissolves the radioactive substances is poured into the soil. The radioactive material is dissolved and extracted, and then purified water is poured into the soil, and the acidic aqueous solution adhering to the soil is washed. In order to enhance the decontamination effect, it is desirable that the extraction operation with an acidic or alkaline aqueous solution or the like and the soil washing operation with purified water are each performed a plurality of times. A mixture of an acidic aqueous solution in which these radioactive substances are dissolved and extracted and soil washing water is contaminated soil decontamination wastewater.

Acidic aqueous solution used for dissolution / extraction of contaminated radioactive materials, soil washing water, etc. must be heated to a fairly high temperature of 60 ° C or higher as necessary to enhance the extraction / decontamination / cleaning effect. In particular, special chemicals such as organic compounds such as complexing agents and halides and ferrocyanides are added to acidic aqueous solutions for dissolution / extraction to facilitate the dissolution of poorly soluble radioactive materials. Sometimes used. For this reason, the treatment of contaminated soil decontamination wastewater must be treated with acidic or alkaline wastewater containing special chemicals at such high temperatures, and is currently widely used for the purpose of removing dissolved substances and desalting. The treatment process using the reverse osmosis membrane is difficult to apply, and only the pervaporation (PV) process using the ceramic zeolite membrane of the present invention is the only application that can achieve high concentration and purified water recovery. It is a possible processing process.

  In addition, decontamination of soil with low contamination and relatively low radiation levels, such as residual soil on the surface of schoolyards in schools in Fukushima and Ibaraki prefectures, etc. contaminated by the Fukushima Daiichi nuclear power plant accident in March 2011 There are actually many cases where this is unavoidable. In these soil decontamination wastewaters, the dissolved amount of radioactive substances is low, and the conventional decontamination techniques such as the agglutination method and adsorption method do not have high removal efficiency. A large amount of waste will be generated.

  In such a case as well, by applying the concentration process of radioactive material-containing wastewater using the zeolite pervaporation membrane of the present invention, the concentration of the radioactive pollutant is increased, and then the aggregated water is agglomerated. A sufficiently high removal efficiency can be easily obtained by applying a conventional decontamination technique such as a method or an adsorption method. Therefore, it is preferable to acquire and collect the decontamination waste water from which radioactive substances are separated and removed from radioactively contaminated soil using an acidic or alkaline aqueous solution and purified water substantially free of radioactive substances.

(Efficient cooling of hot hot water, etc.)
As described above, in the pervaporation process, water permeates from the liquid phase to the vapor phase and changes through the membrane, so that the latent heat of vaporization moves through the membrane as the membrane permeates. As a result, the temperature of the water to be treated decreases. This can be thought of as a heat exchanger in which the membrane is essentially a heat transfer surface.
Incidentally, the temperature drop at this time is particularly large because the membrane permeation component is water and its latent heat of vaporization is large, and when the amount equivalent to 6% of the water to be treated passes through the membrane, the remaining water to be treated has a temperature drop of about 30 ° C. Occurs and the equivalent of 12% results in a temperature drop of about 60 ° C.
Therefore, the present inventors have studied in detail how to use this phenomenon as a method of cooling hot water in nuclear power generation facilities, etc., invented the following process and apparatus, and clarified its epoch-making effect. .

  The permeation vaporization process for cooling water to be treated for this purpose is not much different from the permeation vaporization process for concentration of radioactive material-containing water and recovery of purified water described above in its basic configuration. However, a heating device for the treated water is basically unnecessary, but when this permeation vaporization process for cooling is installed near the original line in the nuclear facility, the treated water tank or the concentrated water tank is not installed. Can be omitted. If the membrane permeated water is to be discharged outside, it is desirable to install a temporary storage tank from the viewpoint of safety measures.

  In the pervaporation process for cooling the water to be treated, it is particularly desirable to use an ejector as a membrane permeation water vapor collection / condensation system. In this case, normal cooling water or a relatively constant temperature can be used as the operation water for the ejector. Although it is conceivable to directly supply natural cooling water such as stored water or seawater, it is not particularly limited thereto. However, when a large amount of hot water or the like is cooled, a cooling water amount corresponding to the required heat amount for cooling is separately required.

  However, in this cooling pervaporation process, the cooling action is performed in the form of latent heat transfer of evaporation, which is extremely efficient. Compared to the case of a normal shell & tube type indirect heat exchanger that exchanges the same amount of heat, Its volume is at least 1/5 or less. In addition, in the case of heat exchange by latent heat transfer according to the present invention, an indirect heat exchanger such as a shell and tube type is unnecessary, and cooling water is not sensible heat exchange. Less than 10 is enough. In other words, in the case of using an indirect heat exchanger, a large amount of cooling water approximately 10 times or more than the cooling pervaporation process is required. Is required.

In addition, the membrane permeated water that will eventually flow out due to this cooling is highly purified to such an extent that it does not substantially contain radioactive substances, as explained in the above-mentioned items such as concentration of radioactive substances. Basically, external discharge is possible via a temporary storage tank.
By the way, in nuclear power generation facilities, it is essential to maintain radioactive materials containing hot water that needs to be lowered at a relatively high temperature or to maintain cooling in the event of an abnormal situation in a normal cooling system due to a natural disaster, etc. There are various kinds of water containing radioactive substances at low temperatures. For example, a typical example of the former is a suppression pool water attached to a reactor containment vessel, and a typical example of the latter is a pool water for fuel that temporarily stores used nuclear fuel having self-heating properties. In the latter case in particular, the main purpose is to maintain a constant temperature by cooling and removing only the amount of heat corresponding to the amount of heat generated.

  The cooling pervaporation process of the present invention using a zeolite membrane is much more compact than conventional cooling systems and requires less than about 1/10 of the cooling water for the purpose of cooling these radioactive substance-containing waters at high or relatively low temperatures. It ’s the best way. Therefore, by using the latent heat transfer action in the pervaporation (PV) process, the temperature of hot water contacted with high temperature radioactive substance-containing aqueous solution or radioactive equipment, etc., or the inclusion of radioactive substances in contact with exothermic substances It is preferable to obtain and collect purified water substantially free of the radioactive substance while maintaining a constant temperature of water.

  FIG. 4 conceptually shows a specific example of these processes and apparatuses of the present invention, but is not limited to this example. These processes and devices of the present invention, that is, a hot water-resistant, acid-resistant, radiation-resistant zeolite pervaporation membrane that concentrates radioactive substance-containing water and recovers purified water substantially free of radioactive substance at a high recovery rate. The osmosis vaporization process and device for concentration using water, or the osmosis vaporization process and device for cooling for cooling or maintaining cooling of high-temperature radioactive material-containing water, etc. are limited to water containing radioactive material. However, the present invention can also be applied to an aqueous solution containing a toxic substance or the like whose external leakage is strictly regulated and an aqueous solution containing a solute that is substantially difficult to separate and concentrate by other separation methods.

Hereinafter, the present invention will be described more specifically based on reference examples and examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the present invention, in order to schematically show treatment of radiation-containing water with a zeolite membrane, a simulation experiment for concentrating water containing cesium chloride or strontium chloride is shown as a reference example. (Reference Example 1)
Using deionized water, 1 L of an aqueous solution containing 0.13% by weight of cesium chloride and 0.18% by weight of strontium chloride was prepared as a liquid to be separated. Using a CHA-type zeolite membrane (inorganic porous support described in JP2011-121040-CHA-type zeolite membrane composite) at 40 ° C., water is selectively permeated from the liquid to be separated by a pervaporation method. It was.
The CHA zeolite membrane had a SiO ₂ / Al ₂ O ₃ molar ratio of 16. A schematic diagram of the apparatus used for the pervaporation method is shown in FIG. In FIG. 5, the inside of the zeolite membrane composite of 5 is depressurized by a vacuum pump of 9, and the pressure difference is about 1 atm with the outside where the liquid to be separated is in contact with 4. Due to this pressure difference, water of the permeated substance 4 in the liquid to be separated permeates and permeates through the zeolite membrane composite 5. The permeated material is collected by 7 traps. On the other hand, the non-permeating ionic component stays outside the 5 zeolite membrane. After 2 hours, the water permeation flux was calculated from the weight of the water repaired in the trap and the effective area of the zeolite membrane immersed in the permeate.
The permeation flux was 2.67 kg / (m ² · h). The measurement results are shown in Table 1.

(Reference Example 2)
A liquid to be separated containing cesium chloride and strontium chloride by a pervaporation method using an inorganic porous support-CHA type zeolite membrane composite as in Example 1 except that the temperature of the liquid to be separated was maintained at 75 ° C. From which water was selectively permeated.
The permeation flux at that time was 11.97 kg / (m ² · h). The measurement results are shown in Table 1.

(Reference Example 3)
The liquid to be separated is an aqueous solution of 96.2% by weight of water, 0.13% by weight of cesium chloride, 0.18% by weight of strontium chloride, 2.79% by weight of sodium chloride, 0.524% by weight of calcium chloride, and wt% of magnesium chloride. In the same manner as in Example 1, water was separated from the liquid to be separated containing cesium chloride, strontium chloride, calcium chloride, and magnesium chloride by the pervaporation method using the inorganic porous support-CHA type zeolite membrane composite. Permeated selectively.
The permeation flux at that time was 2.58 kg / (m ² · h), and a permeation flux equivalent to that in Example 1 in which sodium ions, magnesium ions, and calcium ions did not coexist was obtained. The measurement results are shown in Table 1.

(Reference Example 4)
Except for maintaining the temperature of the liquid to be separated at 75 ° C., a cesium chloride, strontium chloride, calcium chloride, chloride, and the like by the pervaporation method using the inorganic porous support-CHA type zeolite membrane composite as in Example 3. Water was selectively permeated from the liquid to be separated containing magnesium.
The permeation flux at that time was 11.90 kg / (m ² · h), and a permeation flux equivalent to that in Example 3 in which sodium ions, magnesium ions, and calcium ions did not coexist was obtained. The measurement results are shown in Table 1.

In addition, the cation concentration in the permeated liquid was measured using an ICP mass spectrometer 7500ce manufactured by Agilent Technologies for cesium ions and strontium ions, and high by Thermo Fisher Scientific for sodium ions, calcium ions, and magnesium ions. Each was measured using a resolution ICP mass spectrometer ELEMENT2 type.
The cesium ion concentration in the permeate was 0.1 ppb or less, which is the detection lower limit of the measurement method.
Strontium ions are also 1.3 ppb, and it can be seen that there is almost no leakage. The measurement results are shown in Table 2.

1 Stirrer 2 Hot water bath 3 Stirrer 4 Liquid to be separated 5 Zeolite membrane composite 6 Pirani gauge 7 Trap for permeate collection 8 Cold trap 9 Vacuum pump

Claims (12)

A membrane separation device for concentrating cesium-containing water,
Metal or ceramic microfiltration device that separates and removes fine particles from cesium-containing water,
A pump for supplying cesium-containing water from which fine particles have been removed to the membrane module;
Removing water from the cesium-containing water by an osmotic vaporization process and concentrating the cesium;
A membrane module including a chabazite-type zeolite membrane containing zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 3 or more,
It has an apparatus for collecting and collecting membrane-permeated water vapor that has passed through the zeolite membrane,
Membrane separator for concentration of cesium-containing water. Microfiltration device is made of metal, according to claim 1 Symbol mounting device and having a function capable of separating and removing 30μm or more fine particles. The apparatus of Claim 1 or 2 equipped with the heating apparatus for heating before to-be-processed water reaches a membrane module. The apparatus of any one of Claims 1-3 which has a metal tank for concentrated water which has radiation resistance, and a tank for purified water made of metal or plastic. The treated water enriched treated zeolite membrane and piping for recirculated supplied as water to be treated, in any one of claims 1 to 4, characterized in that equipping a control valve for adjusting the amount of return The device described. The apparatus of any one of Claims 1-5 equipped with the ejector apparatus for attracting | sucking / collecting the water vapor | steam which permeate | transmitted the zeolite membrane and was decontaminated and purified. The apparatus according to claim 6, wherein the aqueous solution discharged from the ejector is reused as working water for the ejector. A cooling device for cooling the working water of the ejector is provided in order to keep the working steam pressure of the ejector used for sucking and collecting the membrane permeating steam low.
An apparatus according to claim 6 or claim 7 . The radioactive material to any one of claims 1-8, characterized in that to equip a device for removing adsorption or aggregation method or dialysis method, alone or in combination of plural methods in high dose suppression purposes of the processing system The device described. The apparatus according to any one of claims 1 to 9 , wherein the zeolite membrane is a zeolite membrane formed on an inorganic porous support. A method for concentrating cesium-containing water,
Supplying cesium-containing water to a membrane module including a chabazite-type zeolite membrane containing zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 3 or more,
Removing water from the cesium-containing water by an osmotic vaporization process and concentrating the cesium,
A method for concentrating cesium-containing water. The method for concentrating cesium-containing water according to claim 11 , wherein the zeolite membrane is a zeolite membrane formed on an inorganic porous support.