JP2018189515A - Method and device for decontamination treatment of radioactive contaminated water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decontamination treatment method for radioactive contaminated water and a decontamination treatment device thereof capable of increasing an absorption efficiency of a radioactive material adsorption filter for adsorbing the radioactive material upon performing the decontamination treatment of the radioactive contaminated water, and capable of safely exchanging the radioactive material adsorption filter and subjecting the exchanged radioactive material adsorption filter to incineration processing so as to enable the waste volume to be reduced to a large extent.SOLUTION: A method for decontamination treatment of radioactive contaminated water is a decontamination treatment method by allowing a radioactive material adsorption filter 1 fixed with an adsorbent 11 for adsorbing a radioactive material H to transmit a radioactive contaminated water HW and allowing the radioactive material contained in the radioactive contaminated water to be adsorbed on the adsorbent to perform the decontamination treatment. The radioactive material adsorption filter is held by a frame 13 whose outer edge 121 is combustible, and the combustible adsorbent is fixed and formed on a combustible fiber sheet 12 having a shape of a flat film in which the surface of each fiber yarn 122 is subjected to coating treatment by a polymer based protection film 123 in a state exposed from the polymer based protection film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a decontamination treatment method and a decontamination treatment apparatus for radioactively contaminated water contaminated with radioactive substances including cesium and the like.

  A large amount of radioactively contaminated water contaminated with radioactive substances such as cesium has been stored due to the accident at the nuclear power plant that occurred in the March 11th 2011 Pacific Ocean Earthquake. Decontamination is an urgent issue. The invention regarding the decontamination processing method of radioactive contamination water is disclosed by patent document 1, 2, for example.

  For example, as shown in FIG. 13, Patent Document 1 discloses a method of treating a radioactive substance by adsorbing the radioactive substance in the liquid to the adsorbent 102, and adsorbing the liquid (contaminated water) 101 containing the radioactive substance. A method is disclosed that includes a step S01 in which the radioactive material is adsorbed on the adsorbent 102 by contacting the agent 102 and a step S02 in which the liquid 104 containing the adsorbent 102 on which the radioactive material has been adsorbed is cross-flow filtered.

  In the above method, in the step S01 in which the adsorbent 102 is brought into contact with the liquid 101 containing the radioactive substance and the radioactive substance is adsorbed onto the adsorbent 102, the adsorbent 102 and the liquid 101 containing the radioactive substance are brought into contact with each other and mixed. Although there is no particular limitation as long as it is present, a method in which the adsorbent 102 is put into a container containing a liquid containing a radioactive substance, for example, the storage tank 103, and the mixture is stirred and mixed, or a liquid mixture of the adsorbent 102 and the liquid 101 containing the radioactive substance And the like. Examples of the apparatus include a storage tank 103 having a stirring blade inside. Examples of the adsorbent 102 include zeolite formed in the form of fine particles and Prussian blue.

  Further, in the above method, the cross flow filtration in the step S02 of performing the cross flow filtration is performed only by the liquid 104 containing the adsorbent 102 having adsorbed the radioactive substance flowing in parallel to the filtration filter 105a and subjected to the adsorption treatment from the liquid 104. Is a system that passes through the filtration filter vertically and is filtered while producing a crossing flow.

  For example, when a filtration module 105 in which several hundreds of hollow fiber filtration membranes are bundled horizontally and a liquid 104 containing an adsorbent 102 adsorbing a radioactive substance flows through the filtration module 105 from left to right, the radioactive substance The liquid 104 containing the adsorbent 102 that adsorbs the fluid flows on the outside of each hollow fiber type filtration membrane along the filtration membrane surface (longitudinal direction of the hollow fiber), and penetrates the filtration membrane surface vertically in the flow process. The adsorbed liquid soaks inside the hollow fiber membrane and is collected as the filtrate 106. And the liquid 104 containing the adsorbent 102 which made the radioactive substance adsorb | suck is concentrated by the part which the filtrate 106 isolate | separated. The concentrated liquid 107 containing the adsorbent 102 having adsorbed the radioactive substance is returned to the storage tank 103.

  Further, in Patent Document 2, as shown in FIG. 14, a plurality of radioactive substance adsorbents solidified into a bottomed cylindrical shape inside a water storage tank 202 with a lid for a contaminated liquid 201 as filter cylinders 203 are vertically arranged. The suction tube 205 connected to the pump 204 for sucking gas and liquid is disposed in the filter cylinder 203, and the contaminated liquid 201 inside the water storage tank 202 permeates into the filter cylinder 203 and moves. A storage tank 200 for radioactive pollutant liquid is disclosed in which the purified liquid is stored in the filter cylinder 203 so that the purified liquid can be stored inside and can be discharged to the outside through the pump 204.

  Here, the filter cylinder 203 has a weight ratio of 1: 2 to 4 with respect to the powdered cement-based solidified material prepared by mixing alumina with alumina cement as a main component. The powdered radioactive material adsorbent mixed in the above is formed, and necessary water is added to the powdered radioactive material adsorbent and kneaded to be solidified into a predetermined shape. On the inner peripheral surface of the filter cylinder 203, a stainless porous inner cylinder 206 having a large number of fine holes is attached.

JP 2014-66647 A Japanese Patent Laid-Open No. 2006-80486

However, the inventions of Patent Documents 1 and 2 described above have the following problems.
That is, in the invention of Patent Document 1, the liquid 104 containing the adsorbent 102 having adsorbed the radioactive substance is concentrated by the amount of the filtrate 106 separated, and the concentrated liquid 107 is returned to the storage tank 103. Is done. Therefore, a large amount of radioactive material is adsorbed on the adsorbent 102 returned to the storage tank 103 together with the concentrated liquid 107. Therefore, it is necessary to periodically replace the adsorbent 102 returned to the storage tank 103 with a new adsorbent 102.

  However, it is not easy to recover the adsorbent 102 that has adsorbed a large amount of the radioactive substance from the storage tank 103 that stores the liquid (contaminated water) 101 containing the radioactive substance. Further, even if the adsorbent 102 that adsorbs a large amount of radioactive substance is recovered, the adsorbent 102 such as zeolite made of natural minerals or Prussian blue that has a cyano group and may generate hydrogen cyanide when heated, It cannot be easily incinerated. Therefore, there is a problem that the adsorbent 102 adsorbing a large amount of radioactive substance must be disposed of in the ground as it is, and the amount of disposal becomes enormous.

  Further, the filtration module 105 in which several hundreds of hollow fiber filtration membranes are bundled can be clogged due to foreign matter in the liquid (contaminated water) 101 containing radioactive material, particulate adsorbent 102, etc. It is necessary to replace or clean the filter module 105 with a new one. However, since the adsorbent 102 that adsorbs the radioactive substance or the radioactive substance itself is attached to the filtration module 105, there is a problem with respect to safety or the like in the replacement or cleaning operation.

  Further, in order to quickly decontaminate a liquid (contaminated water) 101 containing a large amount of radioactive material stored, it is necessary to install a large number of filtration modules 105 in which hundreds of hollow fiber filtration membranes are bundled, There was a problem that it increased in cost.

  Further, in the invention of Patent Document 2, a plurality of radioactive substance adsorbents solidified into a bottomed cylindrical shape are arranged vertically as a filter cylinder 203 inside a water storage tank 202 with a cover of the contaminated liquid 201, and the filter A suction pipe 205 connected to a pump 204 for sucking gas and liquid is disposed in the cylinder 203 and purified while the contaminated liquid 201 inside the water storage tank 202 permeates and moves into the filter cylinder 203. Therefore, many foreign substances and radioactive substances are unevenly distributed near the outer peripheral surface of the filter cylinder 203 and are easily adsorbed. Therefore, although the radioactive substance adsorbent located in the vicinity of the inner peripheral surface of the filter cylinder 203 can still adsorb the radioactive substance sufficiently, it is necessary to replace the filter cylinder 203 with a new one. Therefore, there is a problem that the cost for the filter cylinder 203 increases.

  In addition, the filter cylinder 203 has a weight ratio of 1: 2 to 4 with respect to the powdered cement-based solidified material prepared by mixing alumina cement as a main component and active silica. Since the mixed granular radioactive substance adsorbent is formed, and necessary water is added to the granular radioactive substance adsorbent and kneaded to be solidified into a predetermined shape, it cannot be easily incinerated. As a result, there has been a problem that the filter cylinder 203 adsorbing a large amount of radioactive substance must be disposed of in the ground as it is, and the amount of disposal becomes enormous.

  The present invention has been made to solve the above problems, and its purpose is to increase the adsorption efficiency of a radioactive substance adsorption filter that adsorbs radioactive substances in the decontamination treatment of radioactively contaminated water. Provide a decontamination treatment method and decontamination treatment equipment for radioactively contaminated water that can safely replace the radioactive substance adsorption filter, incinerate the replaced radioactive substance adsorption filter, and greatly reduce its disposal amount It is to be.

In order to solve the above problems, a decontamination treatment method and a decontamination treatment apparatus for radioactively contaminated water according to the present invention have the following configuration.
(1) Radiation in which radioactive contamination water is allowed to pass through a radioactive substance adsorption filter to which an adsorbent that adsorbs radioactive substances is fixed, and the radioactive substance contained in the radioactive contamination water is adsorbed to the adsorbent and decontaminated. A method for decontamination of nocturned water,
The radioactive substance adsorbing filter is combustible on a flat membrane-like combustible fiber sheet in which the outer edge is held by a combustible frame and the surface of each fiber yarn is coated with a polymer protective film. The adsorbent is fixed and formed in a state exposed from the polymer protective film.

  In the present invention, the radioactive substance adsorption filter is a flat membrane-like combustible fiber sheet in which the outer edge portion is held by a combustible frame and the surface of each fiber yarn is coated with a polymer protective film. Since the combustible adsorbent is fixed and formed in an exposed state from the polymer protective film, the radioactive material adsorption filter that adsorbs the radioactive material is used for decontamination treatment of radioactively contaminated water. Adsorption efficiency can be increased, and the radioactive substance adsorption filter can be replaced safely, and the discarded radioactive substance adsorption filter can be incinerated to greatly reduce the amount of waste.

  That is, in the radioactive substance adsorption filter, the surface of each fiber yarn is coated with a polymer-based protective film, so that the raising of the fiber sheet protruding from the surface of each fiber yarn (fluffing) is reduced, and the space between each fiber is reduced. And the permeability of radioactively contaminated water can be increased. In addition, the adsorbent is fixed to a flat fiber sheet whose surface is covered with a polymer protective film so that the adsorbent is exposed from the polymer protective film. The radioactively contaminated water can be brought into contact with the respective adsorbents fixed to the flat membrane fiber sheet, and the radioactively contaminated water can be decontaminated while improving the adsorption efficiency of the radioactive substance by the adsorbent. . Further, since the outer edge portion of the flat membrane-like fiber sheet is held by the frame body, the frame body can be gripped by a robot or the like and inserted or removed, and the radioactive substance adsorption filter can be safely replaced. Moreover, since the fiber sheet, the adsorbent, and the frame constituting the radioactive substance adsorption filter are all made of combustible substances, only the radioactive substance remains by incinerating the replaced radioactive substance adsorption filter as it is, The amount of waste can be greatly reduced.

  Therefore, according to the present invention, it is possible to increase the adsorption efficiency of the radioactive substance adsorption filter that adsorbs radioactive substances in decontamination treatment of radioactively contaminated water, and to safely replace the radioactive substance adsorption filter, It is possible to provide a method for decontaminating radioactively contaminated water by incinerating the exchanged radioactive substance adsorption filter and greatly reducing the amount of waste.

(2) The method for decontaminating radioactively contaminated water described in (1),
The adsorbent is made of bamboo charcoal that is pulverized into fine particles by pulverization to a size that is greater than the film thickness of the polymer protective film and less than the fiber yarn diameter of the fiber sheet.

  In the present invention, the adsorbent is made of bamboo charcoal finely pulverized to a size not less than the thickness of the polymer protective film and not more than the fiber yarn diameter of the fiber sheet, so that a large amount of radioactive material can be efficiently removed. It can be adsorbed and the decontamination ability of radioactively contaminated water can be further enhanced.

  That is, zeolite and Prussian blue (including Prussian blue type complexes), which are generally known as radioactive material adsorbents, have a structure in which vacancies are provided inside the crystal structure and the radioactive material is adsorbed in the vacancies. is there. However, zeolite, Prussian blue (including Prussian blue complex), etc., are formed by combining three-dimensional primary particles composed of a plurality of crystal structures to form fine particles (secondary particles) used as an adsorbent. Form. Therefore, the radioactive particles can contact the pores of the primary particles located on the outer peripheral side of the secondary particles and adsorb radioactive materials, but they are located on the inner peripheral side of the secondary particles. It is difficult for radioactive polluted water to enter the pores of the primary particles, and it is difficult to adsorb radioactive substances.

  Therefore, when zeolite or Prussian blue (including Prussian blue complex) is used as the adsorbent for radioactive substances, the adsorption efficiency of the radioactive substances cannot be increased unless the size of the secondary particles is made as small as possible. . However, if secondary particles such as zeolite and Prussian blue (including Prussian blue type complex) are made too small, the secondary particles are covered with an adhesive or the like that is fixed to the fiber sheet, and the adsorption function cannot be performed. .

  In contrast, bamboo charcoal, regardless of the size of finely pulverized fine particles, has a large number of pores that adsorb radioactive substances extending in the same direction and penetrating the fine particles (honeycomb structure). Therefore, radioactively contaminated water can penetrate deeply into the fine pores of bamboo charcoal exposed from the polymer protective film, and radioactive substances can be adsorbed at various locations within the pores. In addition, the adsorbent is made of bamboo charcoal finely pulverized to a size not less than the thickness of the polymer protective film and not more than the fiber yarn diameter of the fiber sheet, so that it is easily fixed to the fiber yarn surface of the fiber sheet. Most of the fine particles of bamboo charcoal can be exposed from the polymer protective film. Therefore, the adsorption efficiency of the radioactive substance can be further increased. Therefore, a large amount of radioactive substance can be adsorbed efficiently, and the decontamination ability of radioactively contaminated water can be further enhanced.

(3) The method for decontamination of radioactively contaminated water described in (1) or (2),
The radioactive substance adsorbing filter allows the radioactive polluted water to pass through at a normal pressure a plurality of times.

  In the present invention, the radioactive substance adsorption filter allows the radioactive polluted water to permeate at normal pressure. Therefore, the pressure difference between the liquid pressure before transmission and the liquid pressure after transmission with respect to the radioactive substance adsorption filter becomes substantially zero. Even if the radioactively contaminated water is permeated through the entire fiber sheet formed in a film shape, an excessive load is not applied to the fiber sheet. Therefore, the clearance gap between the fiber yarns of a fiber sheet can be roughened, and a large amount of radioactive contamination water can permeate | transmit in a short time. In addition, even if the gap between the fiber yarns of the fiber sheet is rough, the radioactive substance adsorption filter allows the radioactive polluted water to permeate multiple times, so that the radioactive substance contained in the radioactive contaminated water can be reliably reduced. it can. Also, the radioactive substance adsorbing filter does not apply an excessive load even if radioactive contaminated water permeates through the entire fiber sheet formed in a flat membrane shape, so that the frame body that holds the outer edge of the fiber sheet In addition, the reinforcing structure for the fiber sheet can be omitted or simplified. As a result, it is possible to decontaminate a large amount of radioactively contaminated water while reducing the cost of the radioactive substance adsorption filter.

(4) The method for decontaminating radioactively contaminated water according to any one of (1) to (3),
The polymer protective film is formed by kneading the adsorbent in a solvent solution in which cellulose ether is dissolved in an alkaline aqueous solution, coating the fiber sheet, and then drying.

  In the present invention, the polymer protective film is formed by kneading an adsorbent in a solvent solution in which cellulose ether is dissolved in an alkaline aqueous solution, coating the fiber sheet, and drying the fiber sheet. A cellulose-based protective film having excellent water resistance can be formed on the surface of the yarn, and at the same time, an adsorbent can be fixed to the surface of each fiber yarn by the cellulose-based protective film. In addition, the cellulosic protective film can further reduce the raised hair protruding from the surface of each fiber yarn while increasing the water resistance, and can widen the gap between each fiber, further increasing the permeability of radioactive polluted water. Can do.

(5) A decontamination treatment apparatus used in the decontamination treatment method for radioactively contaminated water described in any one of (1) to (4),
A contaminated water tank that stores the radioactively contaminated water, a relay filtration device that circulates the radioactively contaminated water pumped from the contaminated water tank to remove foreign matter, and the radioactive contamination that has been filtered by the relay filter device An intermediate receiving tank for storing water; and a plurality of filter units to which the radioactive substance adsorbing filter for adsorbing the radioactive substance by circulating the radioactively contaminated water stored in the intermediate receiving tank a plurality of times is detachably mounted; It is characterized by providing.

  In the present invention, a contaminated water tank that stores radioactively contaminated water, a relay filtration device that circulates the radioactively contaminated water pumped from the contaminated water tank to remove foreign matters, and a radioactive contamination that has been filtered by the relay filtration device An intermediate receiving tank for storing water, and a plurality of filter units that are detachably mounted with radioactive substance adsorption filters that circulate radioactive contaminated water stored in the intermediate receiving tank multiple times to adsorb radioactive substances. Therefore, in the decontamination treatment of radioactive polluted water, the adsorption efficiency of the radioactive substance adsorption filter that adsorbs radioactive substances can be increased, the radioactive substance adsorption filter can be replaced safely, and the exchanged radioactive substance adsorption Filters can be incinerated to greatly reduce their waste.

  In other words, it is equipped with a contaminated water tank that stores radioactively contaminated water and a relay filtration device that circulates the radioactively contaminated water pumped up from the contaminated water tank and removes foreign substances. The foreign matter can be removed in advance by the relay filtration device, and the clogging of the radioactive substance adsorption filter can be reduced, and the adsorption efficiency can be increased. In addition, an intermediate receiving tank that stores radioactively contaminated water filtered by a relay filtration device and a radioactive substance adsorption filter that circulates radioactive contaminated water stored in the intermediate receiving tank multiple times to adsorb radioactive substances can be attached and detached. A large amount of radioactive material is added to the adsorbent of the radioactive material adsorption filter by circulating the radioactive polluted water multiple times between the intermediate receiving tank and the filter unit. Can be adsorbed. And after radioactive material content of radioactive contamination water becomes below a regulation value, it can discharge outside from an intermediate receiving tank as treated water. In addition, by removing the radioactive substance adsorption filter that adsorbs a large amount of radioactive substance from the filter unit and subjecting it to incineration as it is, only the radioactive substance remains, and the amount of waste can be greatly reduced.

  Therefore, according to the present invention, it is possible to increase the adsorption efficiency of the radioactive substance adsorption filter that adsorbs radioactive substances in decontamination treatment of radioactively contaminated water, and to safely replace the radioactive substance adsorption filter, It is possible to provide a decontamination processing apparatus for use in a decontamination processing method for radioactively contaminated water, which can incinerate the replaced radioactive substance adsorption filter and greatly reduce its disposal amount.

(6) In the decontamination processing apparatus described in (5),
The filter unit is connected in parallel to the intermediate receiving tank.

  In the present invention, since the filter unit is connected in parallel to the intermediate receiving tank, the radioactive pollutant water stored in the intermediate receiving tank is used for the radioactive substance adsorption filter of each filter unit. Each can be divided and circulated at the same time, and the decontamination time for a large amount of radioactively contaminated water can be shortened. Moreover, the decontamination processing capability of radioactively contaminated water can be easily increased only by increasing the number of filter units.

(7) In the decontamination apparatus described in (5) or (6),
The radioactive contaminated water discharged from the output port of the filter unit is temporarily stored in the return line of the radioactive contaminated water connecting the output port of the filter unit and the return port of the intermediate receiving tank. An auxiliary tank is provided below the output port of the filter unit, and the radioactively contaminated water stored in the auxiliary tank is returned to the intermediate receiving tank through a feed pump.

  In the present invention, radioactive polluted water discharged from the output port of the filter unit is temporarily stored in the return pipe of the radioactive polluted water connecting the output port of the filter unit and the return port of the intermediate receiving tank. An auxiliary tank is placed below the output port of the filter unit, and the radioactively contaminated water stored in the auxiliary tank is returned to the intermediate receiving tank via the feed pump. Thus, it is possible to avoid or reduce the backflow of radioactively contaminated water from the return pipe and to allow a large amount of radioactively contaminated water to pass through quickly. As a result, the radioactively contaminated water in the intermediate receiving tank can be further decontaminated.

(8) In the decontamination processing apparatus described in any one of (5) to (7),
In the filter unit, the radioactive substance adsorption filter is stood and accommodated in a vertical direction, and the radioactive substance adsorption filter is provided with a radioactive contamination water storage case that allows the radioactive substance adsorption filter to pass in the horizontal direction.
The upper end opening of the radioactively contaminated water storage case is provided with a lid member formed so that the radioactive substance adsorption filter can be inserted and removed.

  In the present invention, the filter unit is provided with a radioactively contaminated water storage case for storing the radioactive substance adsorbing filter in an upright direction and allowing the radioactive substance adsorbing filter to permeate the radioactively contaminated water in the horizontal direction. The upper end opening of the radioactively contaminated water storage case is equipped with a lid member formed so that a radioactive substance adsorption filter can be put in and taken out. By opening the lid member, the radioactively contaminated water storage case By simply moving the radioactive substance adsorption filter that adsorbs a large amount of radioactive substance in an upright state in the up-down direction, it can be taken out easily and safely. Therefore, the radioactive substance adsorption filter that has adsorbed a large amount of radioactive substance and the new radioactive substance adsorption filter can be easily and safely exchanged from the upper end opening of the radioactively contaminated water storage case.

(9) In the decontamination processing apparatus described in (8),
The lid member is connected to a cylinder member formed to be extendable in the vertical direction, and the cylinder member is attached to the radioactively contaminated water storage case so as to be rotatable in the horizontal direction.

  In the present invention, the lid member is connected to a cylinder member formed to be extendable in the vertical direction, and the cylinder member is attached to the radioactively contaminated water storage case so as to be rotatable in the horizontal direction. The lid member is separated upward from the upper end opening of the radioactively contaminated water storage case by extending, and the cylinder member is rotated in the left-right direction with respect to the radioactively contaminated water storage case. The lid member spaced upward from the upper end opening of the water storage case can be further moved in the left-right direction. Therefore, the radioactive substance adsorption filter can be taken out from the upper end opening of the radioactively contaminated water storage case in the vertical direction, and a new radioactive substance adsorption filter can be put into the upper end opening of the radioactively contaminated water storage case from the vertical direction. . Therefore, the radioactive substance adsorption filter that adsorbs a large amount of radioactive substance and the new radioactive substance adsorption filter can be more easily and safely exchanged from the upper end opening of the radioactively contaminated water storage case.

  According to the present invention, in the decontamination treatment of radioactively contaminated water, the adsorption efficiency of the radioactive substance adsorption filter that adsorbs the radioactive substance can be increased, and the radioactive substance adsorption filter can be safely replaced and replaced. It is possible to provide a decontamination processing method and a decontamination processing apparatus for radioactively contaminated water, which can incinerate a radioactive substance adsorption filter and greatly reduce its disposal amount.

It is a typical sectional view of a filter unit used for a decontamination processing method of radioactive contamination water concerning this embodiment. It is a top view of the radioactive substance adsorption filter shown in FIG. In the radioactive substance adsorption filter shown in FIG. 1, an adsorbent (atomized bamboo charcoal) is adsorbed on a flat membrane fiber sheet in which the surface of each fiber yarn is coated with a polymer protective film. It is a typical perspective view showing the state fixed in the more exposed state. It is an enlarged view showing the pore of the adsorbent (atomized bamboo charcoal) shown in FIG. It is typical sectional drawing showing the state by which the radioactive substance (for example, cesium cation) is adsorb | sucked to the inner wall of the pore of the bamboo charcoal shown in FIG. It is a typical perspective view showing the structure where a radioactive substance (for example, cesium cation) is adsorb | sucked to the void | hole formed inside the crystal structure of a zeolite. It is a typical perspective view showing the structure where a radioactive substance is adsorbed in the vacancy formed inside the crystal structure of Prussian blue (including Prussian blue type complex). Zeolite, Prussian blue (including Prussian blue type complex), etc. are schematic perspective views showing a state in which primary particles having a plurality of crystal structures are sterically bonded to form fine particles (secondary particles). . It is a whole block diagram of the decontamination processing apparatus (other embodiment) used for the decontamination processing method of the radioactive contamination water which concerns on this embodiment. FIG. 10 is a front view of the filter unit shown in FIG. 9. It is A arrow directional view shown in FIG. FIG. 2 is a side view of a coating / drying apparatus for forming a polymer protective film on the fiber sheet of the radioactive substance adsorption filter shown in FIG. 1 and fixing an adsorbent at the same time. It is a block diagram regarding the decontamination processing method of the radioactive contamination water described in patent document 1. FIG. It is a block diagram regarding the decontamination processing method of the radioactive contamination water described in patent document 2. FIG.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.
First, the decontamination processing method for radioactively contaminated water according to the present embodiment will be described. Next, the decontamination processing apparatus (other embodiment) used for the decontamination processing method of this radioactive contamination water is demonstrated.

<Decontamination method for radioactively contaminated water>
First, the decontamination processing method for radioactively contaminated water according to this embodiment will be described with reference to FIGS. FIG. 1 shows a schematic cross-sectional view of a filter unit used in the method for decontaminating radioactive contaminated water according to this embodiment. FIG. 2 is a plan view of the radioactive substance adsorption filter shown in FIG. 3, in the radioactive substance adsorption filter shown in FIG. 1, an adsorbent (atomized bamboo charcoal) is added to a flat membrane fiber sheet in which the surface of each fiber yarn is coated with a polymer protective film. The typical perspective view showing the state fixed by the state exposed from the molecular type protective film is shown. FIG. 4 shows an enlarged view showing the pores of the adsorbent (atomized bamboo charcoal) shown in FIG. FIG. 5 is a schematic cross-sectional view showing a state where a radioactive substance (for example, cesium cation) is adsorbed on the inner walls of the pores of bamboo charcoal shown in FIG. FIG. 6 is a schematic perspective view showing a structure in which a radioactive substance (for example, cesium cation) is adsorbed in pores formed in the crystal structure of zeolite. FIG. 7 is a schematic perspective view showing a structure in which a radioactive substance is adsorbed in vacancies formed inside the crystal structure of Prussian blue (including Prussian blue type complex). FIG. 8 is a schematic diagram showing a state where zeolite, Prussian blue (including Prussian blue complex), and the like are primary particles having a plurality of crystal structures are sterically bonded to form fine particles (secondary particles). A perspective view is shown.

  As shown in FIGS. 1 to 3, the radioactive contamination water decontamination method according to the present embodiment is applied to the radioactive material adsorption filter 1 to which the adsorbent 11 that adsorbs the radioactive material H is fixed. And the radioactive substance H contained in the radioactively contaminated water HW is adsorbed by the adsorbent 11 and decontaminated. Here, the radioactive substance H means a substance that emits radiation such as α-rays, β-rays, and γ-rays when the atomic nucleus collapses, and examples thereof include cations such as cesium (Cs) and strontium (Sr). It is done. The radioactively contaminated water HW means an aqueous solution containing the radioactive substance H, for example, an aqueous solution containing the radioactive substance H scattered outside due to an accident at a nuclear power plant or the like, or discharged from a reactor cooling system. Examples thereof include an aqueous solution containing the radioactive substance H.

  The radioactive substance adsorption filter 1 is a flat membrane combustible fiber sheet in which the outer edge 121 is held by a combustible frame 13 and the surface of each fiber yarn 122 is coated with a polymer protective film 123. 12, the combustible adsorbent 11 is adhered and formed in a state exposed from the polymer protective film 123. Here, the combustible fiber sheet 12 means a woven fabric or a non-woven fabric formed by fibers excluding non-combustible fibers (for example, glass fibers, metal fibers, etc.), but the fibers are easily ignited. Swellable fibers (such as cotton, hemp, rayon) that spread immediately, or flammable fibers (such as hair, silk, nylon, polyester, etc.) that easily ignite but slowly burn preferable. In addition, the fiber sheet 12 has a thickness dimension because it can secure a predetermined tensile strength and can take a large gap between the fiber yarns to easily improve the permeability of the radioactively contaminated water HW. Is preferably about 2 to 3 mm. Moreover, it is preferable that the combustion temperature of the frame 13, the fiber sheet 12, and the adsorbent 11 constituting the radioactive substance adsorption filter 1 is 600 ° C. or less. In addition, the fiber sheet 12 may be hold | maintained at the frame 13 in the state which piled up several sheets.

  The polymer protective film 123 means a protective film made of a polymer-based natural substance or synthetic substance. For example, a cellulose-based protective film 123S formed with a film thickness of several μm to several tens of μm is preferable. The cellulose-based protective film 123S is formed, for example, by kneading the adsorbent 11 (T) in a solvent solution in which cellulose ether is dissolved in an alkaline aqueous solution, coating the fiber sheet 12, and drying it after neutralization. The coating / drying apparatus will be described later.

  Moreover, the combustible frame 13 corresponds to, for example, a wooden frame formed in a rectangular annular body with a substantially constant width. A rectangular flat membrane-like combustible fiber sheet 12 whose outer surface 121 is coated with a polymer protective film 123 on the surface of each fiber yarn 122 is attached to a wooden frame formed in a quadrangular annular body. 131 are connected. The outer edge portion 121 of the fiber sheet 12 is connected to the side surface on the input port 211 side of the radioactively contaminated water HW in the frame body 13 by stop members 131 arranged at substantially equal intervals in the circumferential direction. The stopper member 131 may be, for example, a U-shaped needle (stapler).

  The combustible adsorbent 11 is, for example, fine particles such as bamboo charcoal, coconut shell charcoal, and charcoal, but is larger than the film thickness d2 of the polymer protective film 123 and smaller than the fiber yarn diameter d3 of the fiber sheet 12. It is preferably made of bamboo charcoal T which has been pulverized into fine particles d1. The size d1 of the finely divided bamboo charcoal T is more preferably measured by a sieving method (based on a test method specified in JIS Z8801) and passing through openings of about 140 to 160 mesh. . The bamboo charcoal before atomization is preferably formed by burning a finely cut bamboo chip and then quenching it with water or the like.

  In addition, as shown in FIGS. 4 and 5, the bamboo charcoal T has a large number of fine pores 111 that adsorb the radioactive substance H extending in substantially the same direction regardless of the size of the finely pulverized fine particles. It is formed in a structure (honeycomb structure) penetrating through. Therefore, the radioactive polluted water HW can infiltrate deeply into the pores 111 in the finely divided bamboo charcoal T exposed from the polymer protective film 123 shown in FIG. 3, and the radioactive substance H is put in each recess in the pores 111. Can be adsorbed.

  In comparison, as shown in FIGS. 6 to 8, zeolite Z1 and Prussian blue Z2 (including Prussian blue type complex), which are generally known as adsorbents for radioactive substances, are vacant inside the crystal structure. The structure includes holes K1 and K2, and the radioactive substance H is adsorbed in the holes K1 and K2. However, zeolite Z1, Prussian blue Z2 (including Prussian blue complex), and the like are fine particles (primary particles Z11, Z21 having a plurality of crystal structures are sterically bonded and used as an adsorbent ( Secondary particles Z12, Z22) are formed. Therefore, radioactive polluted water HW can come into contact with the pores K1 and K2 of the primary particles Z11 and Z21 located on the outer peripheral side of the secondary particles Z12 and Z22, and the radioactive substance H can be adsorbed. The radioactive polluted water HW hardly enters the vacancies K1 and K2 of the primary particles Z11 and Z21 located on the inner peripheral side of the secondary particles Z12 and Z22, and it is difficult to adsorb the radioactive substance H.

  Therefore, when using zeolite Z1 or Prussian blue Z2 (including Prussian blue type complex) as the adsorbent 11 of the radioactive substance H, the radioactive substance must be made unless the size d4 of the secondary particles Z12 and Z22 is made as small as possible. The adsorption efficiency of H cannot be increased. However, if the secondary particles Z12 and Z22 such as zeolite Z1 and Prussian blue Z2 (including Prussian blue type complex) are made too small, the secondary particles Z12 are bonded to the fiber sheet 12 by the adhesive or the polymer protective film 123. Z22 is covered, and there is a problem that the adsorption function cannot be performed. Further, there is a problem that it is not possible to easily incinerate zeolite Z1 made of natural minerals, Prussian blue Z2 having a cyano group and generating hydrogen cyanide when heated. Therefore, zeolite Z1 or Prussian blue Z2 (including Prussian blue type complex) or the like is not used for the adsorbent 11 used in the method for decontaminating radioactively contaminated water according to this embodiment.

  Moreover, as shown in FIG. 1, it is preferable to let the radioactive substance adsorption filter 1 permeate the radioactively contaminated water HW a plurality of times at normal pressure. The normal pressure means a pressure equal to the atmospheric pressure and corresponds to approximately 1 atmosphere (≈1013 hPa). The number of times the radioactive contaminated water HW is transmitted is preferably about 2 to 4 times, but is appropriately set according to the permeation amount of the radioactive contaminated water HW per hour and the content per volume of the radioactive substance H. Further, by allowing the radioactive polluted water HW to permeate at normal pressure, the pressure difference between the liquid pressure V1 before permeation to the radioactive substance adsorption filter 1 and the liquid pressure V2 after permeation becomes substantially zero and is formed in a flat film shape. In addition, the radioactively contaminated water HW can be transmitted substantially uniformly through the entire fiber sheet 12. Even in this case, an excessive load is not applied to the radioactive substance adsorption filter 1. Therefore, the frame 13 holding the outer edge portion 121 of the fiber sheet 12 and the reinforcing structure for the fiber sheet 12 are not required or can be simplified. For example, a reinforcing frame or the like that supports the central portion of the fiber sheet 12 is not attached to the frame body 13 that is formed into a quadrangular annular body with a substantially constant width.

<Decontamination equipment used for the method of decontamination of radioactively contaminated water>
Next, the decontamination processing apparatus (other embodiment) used for the decontamination processing method of radioactive contamination water which concerns on this embodiment is demonstrated using FIG. 1, FIG. 9-FIG. In FIG. 9, the whole block diagram of the decontamination processing apparatus (other embodiment) used for the decontamination processing method of the radioactive contamination water which concerns on this embodiment is shown. FIG. 10 shows a front view of the filter unit shown in FIG. FIG. 11 is a view taken in the direction of arrow A shown in FIG. FIG. 12 shows a side view of a coating / drying apparatus for forming a polymer protective film on the fiber sheet of the radioactive substance adsorption filter shown in FIG. 1 and fixing the adsorbent at the same time.

  As shown in FIGS. 1 and 9 to 11, the decontamination treatment apparatus 10 circulates the contaminated water tank 3 storing the radioactively contaminated water HW and the radioactively contaminated water HW pumped from the contaminated water tank 3. The intermediate filtration device 4 for removing the foreign matter X, the intermediate receiving tank 5 for storing the radioactive contaminated water HW filtered by the relay filtration device 4, and the radioactive contaminated water HW stored in the intermediate receiving tank 5 are circulated a plurality of times. And a plurality of filter units 2 to which a radioactive substance adsorption filter 1 for adsorbing the radioactive substance H is detachably mounted.

  Specifically, the contaminated water tank 3 is connected to a tank body 31 for storing the radioactively contaminated water HW, a pumping pump 32 for pumping up the radioactively contaminated water HW stored in the tank body 31, and the pumping pump 32. In addition, the pumping pump 32 is operated to supply the radioactively contaminated water HW stored in the tank body 31 to the relay filtration device 4 via the contaminated water supply conduit 33.

  The relay filtration device 4 includes a first filter 42, a second filter 43, and a third filter 44 that filter the radioactively contaminated water HW supplied from the contaminated water tank 3, and foreign matter separated from each filter. A transport conveyor 45 that transports X, a collection box 48 that collects the foreign matter X transported by the transport conveyor 45, a storage tank 41 that stores radioactively contaminated water HW that has passed through each filter, and a storage tank 41 that stores An intermediate return pipe 46 for returning the radioactive contaminated water HW to the second filter 43 and the third filter 44, and a feed pump 461 for sending the radioactive contaminated water HW from the storage tank 41 to the intermediate return pipe 46. And.

  In addition, the first filter 42, the second filter 43, and the third filter 44 are wedge wires each having a slit interval of a predetermined width in order to separate foreign substances contained in the radioactively contaminated water HW in order from a larger one. Has a screen. The slit interval of the wedge wire screen is formed narrower in the order of the first filter 42, the second filter 43, and the third filter 44. The intermediate return pipe 46 has an open / close valve 431 that shuts off the radioactive contaminated water HW returned to the second filter 43 and an open / close valve 441 that shuts off the radioactive contaminated water HW returned to the third filter 44. And.

  Moreover, the operating method of the relay filtration apparatus 4 is performed as follows. That is, the pumping pump 32 is operated to allow the radioactive contaminated water HW stored in the contaminated water tank 3 to pass through the first filter 42, thereby increasing the gap between the slits of the wedge wire screen provided in the first filter 42. Remove foreign objects of size. Thereafter, only the on-off valve 431 that shuts off the radioactively contaminated water HW to be returned to the second filter 43 is opened, and the feed pump 461 is operated for a certain period of time. At this time, by allowing the radioactively contaminated water HW stored in the storage tank 41 to pass through only the second filter 43, foreign matters having a size larger than the slit interval of the wedge wire screen provided in the second filter 43 are removed. .

  Furthermore, only the on-off valve 441 that shuts off the radioactively contaminated water HW to be returned to the third filter 44 is opened, and the feed pump 461 is operated for a certain period of time. At this time, by allowing the radioactively contaminated water HW stored in the storage tank 41 to pass through only the third filter 44, foreign matters having a size larger than the slit interval of the wedge wire screen provided in the third filter 44 are removed. . As described above, the relay filtration device 4 is operated, and the foreign matter X having a certain size or more contained in the radioactively contaminated water HW is removed in advance before the radioactive substance H is adsorbed.

  Further, the intermediate return pipe 46 is provided with a branch pipe 47 for supplying the radioactive contaminated water HW filtered by the relay filtration device 4 to the intermediate receiving tank 5. The branch pipe 47 is provided with an open / close valve 471 for blocking the radioactively contaminated water HW supplied to the intermediate receiving tank 5. The radioactively contaminated water HW from which the foreign substance X having a certain size or larger has been removed in advance by the relay filtration device 4 closes the on-off valves 431 and 441 of the intermediate feedback pipe 46 and opens the on-off valve 471 of the branch pipe 47. Then, the feed pump 461 is operated to move from the storage tank 41 to the intermediate receiving tank 5.

  The plurality of filter units 2 are connected in parallel to the intermediate receiving tank 5. Between the intermediate receiving tank 5 and each filter unit 2, a supply conduit 51 and a return conduit 52 for the radioactively contaminated water HW are provided. The supply pipe 51 is connected from an output port 511 provided in the lower part of the intermediate receiving tank 5 to an input port 211 provided in the lower part of each filter unit 2 via a feed pump 512.

  The return pipe 52 is connected from an output port 212 provided at the upper part of each filter unit 2 to a return port 521 provided at the upper part of the intermediate receiving tank 5 via a feed pump 522. On-off valves are respectively attached to the input port 211 and the output port 212 of each filter unit 2. In addition, the supply pipe 51 includes a discharge pipe 54 that discharges from the intermediate receiving tank 5 to the outside as the treated water SW after the radioactive substance content of the radioactively polluted water HW becomes less than a specified value, and an opening / closing valve 541 thereof. Is connected.

  Note that radiation discharged from the output port 212 of the filter unit 2 is connected to the return conduit 52 of the radioactively contaminated water HW connecting the output port 212 of each filter unit 2 and the return port 521 of the intermediate receiving tank 5. An auxiliary tank 6 for temporarily storing the active contaminated water HW is provided below the output port 212 of the filter unit 2, and the radioactive contaminated water HW stored in the auxiliary tank 6 is supplied to the intermediate receiving tank 5 via the feed pump 522. It is preferable to return to the return port 521. This is because by providing the auxiliary tank 6 below the output port 212 of the filter unit 2, the backflow of the radioactively contaminated water HW discharged from the output port 212 of the filter unit 2 can be easily avoided or reduced.

  The filter unit 2 accommodates a radioactive substance adsorption filter 1 arranged upright in the vertical direction, and allows the radioactive substance adsorption filter 1 to transmit the radioactive contamination water HW in the left-right direction. A storage case 21 is provided. The radioactive substance adsorption filter 1 is arranged vertically at a substantially central portion in the left-right direction of the radioactively contaminated water storage case 21. In addition, a lid member 22 formed so that the radioactive substance adsorption filter 1 can be loaded and unloaded is attached to the upper end opening 213 of the radioactively contaminated water storage case 21.

  In addition, when letting radioactive substance adsorption filter 1 permeate | transmit radioactivity contaminated water HW by a normal pressure, it is possible to permeate | transmit radioactivity contaminated water HW substantially uniformly to the fiber sheet 12 formed in flat film shape entirely. Therefore, it is not necessary to intervene a sealing member between the frame 13 of the radioactive substance adsorption filter 1 and the inner wall of the radioactively contaminated water storage case 21. By eliminating the need for a sealing member between the radioactive substance adsorption filter 1 and the radioactively contaminated water storage case 21, it is possible to further simplify the loading / unloading operation of the radioactive substance adsorption filter 1 with respect to the filter unit 2.

  Further, the lid member 22 is connected to a cylinder member 23 formed to be extendable in the vertical direction, and the cylinder member 23 is attached to the radioactively contaminated water storage case 21 so as to be rotatable in the left-right direction. That is, the rod portions 231 and 231 of the cylinder members 23 and 23 are connected to the front end portion 221 and the rear end portion 222 of the lid member 22 extending in the front-rear direction. Case lower end portions 232 and 232 of the cylinder members 23 and 23 are pivotally supported by support portions 223 and 224 protruding from the front and rear side walls of the radioactively contaminated water storage case 21. Further, brackets 233 and 233 extending to the left are fixed to the case lower end portions 232 and 232 of the cylinder members 23 and 23, and the auxiliary cylinder members 24 and 24 are formed on the brackets 233 and 233 so as to be vertically extendable. Rod parts 241 and 241 are connected. The lower end portions 242 and 242 of the auxiliary cylinder member 24 are pivotally supported by support portions 223 and 224 that protrude from the front and rear side walls of the radioactively contaminated water storage case 21.

  Therefore, when the cylinder members 23 and 23 are extended, the lid member 22 is separated upward from the upper end opening 213 of the radioactively contaminated water storage case 21, and the auxiliary cylinder members 24 and 24 are extended, thereby The members 23 and 23 are rotated in the left-right direction with respect to the radioactively contaminated water storage case 21. Thereby, the lid member 22 separated upward from the upper end opening 213 of the radioactively contaminated water storage case 21 can be further moved in the left-right direction. Therefore, the radioactive substance adsorption filter 1 is taken out from the upper end opening 213 of the radioactively contaminated water storage case 21 in the vertical direction, and the new radioactive substance adsorption filter 1 is inserted into the upper end opening 213 of the radioactively contaminated water storage case 21 in the vertical direction. Can be put in.

  Next, the coating / drying apparatus 20 for forming the polymer protective film 123 on the fiber sheet 12 of the radioactive substance adsorption filter 1 shown in FIGS. 1 and 3 and fixing the adsorbent 11 (T) at the same time will be described. To do. As shown in FIG. 12, the coating / drying apparatus 20 includes a coating unit 60, a heater unit 7, a cylinder drying unit 8, and a winding unit 9.

  Specifically, the coating unit 60 includes an unwinder 62 that unwinds the raw fabric 61 in which a strip-shaped nonwoven fabric 611 is wound in a coil shape, a squeegee coater 63 that coats the unwound nonwoven fabric 611, and a squeegee coater. The feed roller 64 is disposed opposite to the feed roller 63 and feeds the nonwoven fabric 611. The fiber yarn (for example, polyester fiber) of the nonwoven fabric 611 corresponds to the fiber yarn 122 constituting the fiber sheet 12 of the radioactive substance adsorption filter 1. In the squeegee coater 63, a raw material component (for example, cellulose ether) of the polymer protective film 123 covering the surface of the fiber yarn 122 constituting the fiber sheet 12, finely divided bamboo charcoal T, a necessary binder component and the like are used as a solvent. The pasty coating liquid kneaded with the liquid is applied to the unwound nonwoven fabric 611.

  The heater unit 7 is a drying chamber equipped with a gas stove, a far infrared heater, and the like. When the non-woven fabric 611 coated with the squeegee coater 63 is allowed to pass through the heater unit 7, a polymer component or a binder component that covers the surface of the fiber yarn is rapidly removed by rapidly removing moisture contained in the coating solution. Concentrate to prevent shedding from the fiber yarn surface.

  In the cylinder drying section 8, a plurality of hollow cylinder bodies 81 and 82 are arranged in a staggered manner in two upper and lower rows, and the nonwoven fabric 611 that has passed through the heater section 7 is replaced with the outer peripheral surfaces of the hollow cylinder bodies 81 and 82 alternately up and down. Passing while winding around. The hollow cylinder body 81 on the upstream side in the feed direction is heated by steam heat, but the hollow cylinder body 82 on the downstream side in the feed direction is cooled by the refrigerant. By passing the nonwoven fabric 611 through the plurality of hollow cylinder bodies 81 and 82, the polymer component and the binder component covering the surface of the fiber yarn are solidified, and the surface of each fiber yarn is coated with the polymer protective film 123. At the same time, the finely divided bamboo charcoal T is fixed to the surface of each fiber yarn.

  The winding unit 9 includes a winding machine 91 that winds the coated and dried strip-shaped nonwoven fabric 611 in a coil shape, and a drive motor 92 for the winding machine 91. The surface of each fiber yarn 122 is coated with a polymer protective film 123, and the strip-shaped non-woven fabric 611 in which finely divided bamboo charcoal T is fixed to the surface of each fiber yarn 122 is coiled by the winding unit 9. In the state of being wound around, it is transported to a cutting device (not shown) and cut into a size necessary for the radioactive substance adsorption filter 1 for use.

<Effect>
As described above in detail, according to the method for decontaminating radioactive water according to the present embodiment, the radioactive substance adsorption filter 1 is held by the frame 13 whose outer edge 121 can be combusted and each fiber yarn. The combustible adsorbent 11 is fixed to the flat membrane-like combustible fiber sheet 12 whose surface is coated with the polymer protective film 123 in a state of being exposed from the polymer protective film 123, As it is formed, it is possible to increase the adsorption efficiency of the radioactive substance adsorption filter 1 that adsorbs the radioactive substance H in the decontamination process of the radioactively contaminated water HW, and to replace the radioactive substance adsorption filter 1 safely. It is possible to incinerate the exchanged radioactive substance adsorption filter 1 and greatly reduce the amount of waste.

  That is, since the surface of each fiber yarn 122 is coated with the polymer protective film 123, the radioactive substance adsorption filter 1 reduces the raising (fluffing) protruding from the surface of each fiber yarn 122 in the fiber sheet 12. Thus, the gap between the fibers can be enlarged, and the permeability of the radioactively contaminated water HW can be increased. Further, since the adsorbent 11 is fixed to the flat fiber sheet 12 in which the surface of each fiber yarn 122 is coated with the polymer protective film 123 while being exposed from the polymer protective film 123. The radioactively contaminated water HW with increased permeability can come into contact with the respective adsorbents 11 fixed to the flat membrane-like fiber sheet 12, increasing the adsorption efficiency of the radioactive substance H by the adsorbent 11, and increasing the radioactivity. Contaminated water HW can be decontaminated. Further, since the outer edge portion 121 of the flat membrane fiber sheet 12 is held by the frame body 13, the frame body 13 can be gripped by a robot or the like and can be inserted or removed, and the radioactive substance adsorption filter 1 can be safely replaced. can do. Further, since the fiber sheet 12, the adsorbent 11 and the frame 13 constituting the radioactive substance adsorption filter 1 are all made of combustible substances, the radioactive substance can be incinerated by incinerating the exchanged radioactive substance adsorption filter 1 as it is. Only H remains, and the amount of waste can be greatly reduced.

  Therefore, according to the present embodiment, the adsorption efficiency of the radioactive substance adsorption filter 1 that adsorbs the radioactive substance H can be increased in the decontamination process of the radioactively contaminated water HW, and the radioactive substance adsorption filter 1 is It is possible to provide a method for decontaminating radioactively contaminated water that can be safely exchanged, incinerate the exchanged radioactive substance adsorption filter 1 and greatly reduce the amount of waste.

  Further, according to the present embodiment, the adsorbent 11 is made of bamboo charcoal T that is pulverized to a size d1 that is equal to or greater than the thickness of the polymer protective film 123 and equal to or less than the fiber yarn diameter of the fiber sheet 12. A large amount of radioactive substance H can be adsorbed efficiently, and the decontamination ability of the radioactively contaminated water HW can be further enhanced.

That is, zeolite Z1 or Prussian blue Z2 (including Prussian blue type complex), which is generally known as an adsorbent for radioactive substance H, has pores K1, K2 inside the crystal structure, and the pores K1, K2 In this structure, radioactive material H (Cs ⁺ ) is adsorbed on the surface. However, zeolite Z1, Prussian blue Z2 (including Prussian blue complex), and the like are fine particles (primary particles Z11, Z21 having a plurality of crystal structures are sterically bonded and used as an adsorbent ( Secondary particles Z12, Z22) are formed. Therefore, radioactive polluted water HW can come into contact with the pores K1 and K2 of the primary particles Z11 and Z21 located on the outer peripheral side of the secondary particles Z12 and Z22, and the radioactive substance H can be adsorbed. The radioactive polluted water HW hardly enters the vacancies K1 and K2 of the primary particles Z11 and Z21 located on the inner peripheral side of the secondary particles Z12 and Z22, and it is difficult to adsorb the radioactive substance H.

  Therefore, when using zeolite Z1 or Prussian blue Z2 (including Prussian blue type complex) as an adsorbent for the radioactive substance H, it is necessary to reduce the size d4 of the secondary particles Z12 and Z22 as much as possible. The adsorption efficiency cannot be increased. However, if the secondary particles Z12 and Z22 such as zeolite Z1 and Prussian blue Z2 (including Prussian blue type complex) are made too small, the secondary particles Z12 are bonded to the fiber sheet 12 by an adhesive or a polymer protective film 123. Z22 is covered, and there is a problem that the adsorption function cannot be performed.

  On the other hand, the bamboo charcoal T has a structure in which a large number of pores 111 that adsorb the radioactive substance H extend in substantially the same direction and penetrate through the fine particles of the bamboo charcoal T regardless of the size d1 of finely pulverized fine particles. Nest-like structure), the radioactive polluted water HW can infiltrate deeply into the fine pores 111 in the finely divided bamboo charcoal T exposed from the polymer protective film 123, and each concave in the fine pores 111 The radioactive substance H can be adsorbed at the place. Further, since the adsorbent 11 is made of bamboo charcoal T which is finely pulverized to a fiber yarn diameter d3 or less of the fiber sheet 12 with a film thickness d2 or more of the polymer protective film 123, the fiber yarn 122 of the fiber sheet 12 It is easy to adhere to the surface, and most of the fine particles of bamboo charcoal T can be exposed from the polymer protective film 123. Therefore, the adsorption efficiency of the radioactive substance H can be further increased. Therefore, a large amount of radioactive substance H can be adsorbed efficiently, and the decontamination ability of the radioactively contaminated water HW can be further enhanced.

  In addition, according to the present embodiment, the radioactive substance adsorption filter 1 allows the radioactive polluted water HW to permeate at normal pressure, so that the liquid pressure V1 before permeation to the radioactive substance adsorption filter 1 and the liquid pressure V2 after permeation Even if the radioactively contaminated water HW is permeated through the entire fiber sheet 12 formed in a flat film shape, an excessive load is not applied to the fiber sheet 12. Therefore, the clearance gap between the fiber yarns of the fiber sheet 12 can be roughened, and the radioactive contamination water HW can be permeated in a large amount in a short time. Even if the gap between the fiber yarns of the fiber sheet 12 is made rough, the radioactive substance adsorbing filter 1 allows the radioactive polluted water HW to permeate a plurality of times, so that the radioactive substance H contained in the radioactive polluted water HW is surely contained. Can be reduced. Moreover, even if the radioactive contamination water HW permeate | transmits the whole fiber sheet 12 formed in flat membrane shape at the radioactive substance adsorption filter 1, since an excessive load is not applied, the outer edge part 121 of the fiber sheet 12 is not carried out. A reinforcing structure for the frame body 13 and the fiber sheet 12 that hold the sheet can be unnecessary or simplified. As a result, it is possible to decontaminate a large amount of radioactively contaminated water HW while reducing the cost of the radioactive substance adsorption filter 1.

  Further, according to the present embodiment, the polymer protective film 123 is dried after the adsorbent 11 (T) is kneaded in a solvent solution obtained by dissolving cellulose ether in an alkaline aqueous solution and applied to the fiber sheet 12. Therefore, the cellulose-based protective film 123S having excellent water resistance can be formed on the surface of each fiber yarn 122 in the fiber sheet 12, and at the same time, the adsorbent 11 (T ) Can be fixed. In addition, the cellulose-based protective film 123S can further increase the water resistance while further reducing the protruding hairs protruding from the surface of each fiber yarn 122 to enlarge the gaps between the fibers, thereby increasing the permeability of the radioactive polluted water HW. It can be further enhanced.

  According to the treatment apparatus 10 used in the method for decontaminating radioactive contaminated water according to the other embodiment, the contaminated water tank 3 storing the radioactive contaminated water HW, and the radioactive contamination pumped up from the contaminated water tank 3 are used. Relay filtration device 4 that circulates water HW to remove foreign matter X, intermediate receiving tank 5 that stores radioactively contaminated water HW filtered by relay filtering device 4, and radioactively contaminated water that is stored in intermediate receiving tank 5 A plurality of filter units 2 to which a radioactive substance adsorption filter 1 that circulates HW a plurality of times to adsorb radioactive substance H is detachably mounted; Thus, the adsorption efficiency of the radioactive substance adsorption filter 1 that adsorbs the radioactive substance H can be increased, the radioactive substance adsorption filter 1 can be safely replaced, and the exchanged radioactive substance adsorption filter 1 is incinerated. The amount of waste can be significantly reduced.

  That is, since the contaminated water tank 3 that stores the radioactive contaminated water HW and the relay filtration device 4 that circulates the radioactive contaminated water HW pumped from the contaminated water tank 3 and removes the foreign matter X are provided. Various foreign substances X contained in the contaminated water HW can be removed in advance by the relay filtration device 4, and the clogging of the radioactive substance adsorption filter 1 can be reduced and its adsorption efficiency can be increased. In addition, an intermediate receiving tank 5 that stores the radioactive contaminated water HW filtered by the relay filtration device 4 and a radioactive substance that adsorbs the radioactive substance H by circulating the radioactive contaminated water HW stored in the intermediate receiving tank 5 a plurality of times. And a plurality of filter units 2 to which the adsorption filter 1 is detachably mounted, so that radioactive polluted water HW circulates between the intermediate receiving tank 5 and the filter unit 2 a plurality of times, thereby causing radioactive substances. A large amount of radioactive substance H can be adsorbed on the adsorbent 11 of the adsorption filter 1. And after radioactive material content of the radioactive contamination water HW becomes below a regulation value, it can discharge to the outside from the intermediate receiving tank 5 as treated water SW. Further, the radioactive substance adsorption filter 1 that adsorbs a large amount of the radioactive substance H is taken out from the filter unit 2 and incinerated as it is, so that only the radioactive substance H remains and the amount of waste can be greatly reduced.

  Therefore, according to this other embodiment, in the decontamination process of the radioactively contaminated water HW, the adsorption efficiency of the radioactive substance adsorption filter 1 that adsorbs the radioactive substance H can be increased, and the radioactive substance adsorption filter 1 can be safely exchanged, and the treatment apparatus 10 used for the decontamination treatment method of radioactively contaminated water can be provided by incineration of the exchanged radioactive substance adsorption filter 1 and greatly reducing the amount of waste.

  Moreover, according to this other embodiment, since the filter unit 2 is connected in parallel to the intermediate receiving tank 5, the radioactive substance adsorbing filter 1 of each filter unit 2 is provided in the intermediate receiving tank 5. The radioactively contaminated water HW stored in can be divided for each filter unit 2 and circulated simultaneously, and the decontamination time for a large amount of radioactively contaminated water HW can be shortened. Moreover, the decontamination processing capability of the radioactively contaminated water HW can be easily increased only by increasing the number of filter units 2.

  Further, according to the other embodiment, the return line 52 of the radioactively contaminated water HW connecting the output port 212 of the filter unit 2 and the return port 521 of the intermediate receiving tank 5 is connected to the filter unit 2. An auxiliary tank 6 for temporarily storing radioactive contaminated water HW discharged from the output port 212 is provided below the output port 212 of the filter unit 2, and the radioactive contaminated water HW stored in the auxiliary tank 6 is supplied to the feed pump 522. Since it is returned to the intermediate receiving tank 5 via the, the backflow of the radioactive polluted water HW from the return pipe 52 is avoided or reduced with respect to the radioactive substance adsorption filter 1 of each filter unit 2, and a large amount of radioactive contamination Water HW can be rapidly permeated. As a result, the radioactively contaminated water HW in the intermediate receiving tank 5 can be decontaminated more rapidly.

  Further, according to the other embodiment, the filter unit 2 accommodates the radioactive substance adsorption filter 1 upright in the vertical direction, and the radioactive polluted water HW in the horizontal direction with respect to the radioactive substance adsorption filter 1. Since the radioactive contaminated water storage case 21 is made to pass therethrough, the upper end opening 213 of the radioactive contaminated water storage case 21 is fitted with a lid member 22 formed so that the radioactive substance adsorption filter 1 can be loaded and unloaded. By simply opening the lid member 22, the radioactive substance adsorption filter 1 that adsorbs a large amount of radioactive substance H in an upright state is moved up and down from the upper end opening 213 of the radioactively contaminated water storage case 21. It can be easily and safely removed. Therefore, the radioactive substance adsorption filter 1 that adsorbs a large amount of radioactive substance H and the new radioactive substance adsorption filter 1 can be easily and safely exchanged from the upper end opening 213 of the radioactively contaminated water storage case 21.

  According to the other embodiment, the lid member 22 is connected to the cylinder member 23 formed to be extendable in the vertical direction, and the cylinder member 23 is rotated in the horizontal direction to the radioactively contaminated water storage case 21. Since the cylinder member 23 extends, the lid member 22 is separated upward from the upper end opening 213 of the radioactively contaminated water storage case 21, and the cylinder member 23 is moved away from the radioactively contaminated water storage case. The lid member 22 separated upward from the upper end opening 213 of the radioactively contaminated water storage case 21 can be further moved in the left-right direction by rotating in the left-right direction with respect to 21. Therefore, the radioactive substance adsorption filter 1 is taken out from the upper end opening 213 of the radioactively contaminated water storage case 21 in the vertical direction, and the new radioactive substance adsorption filter 1 is inserted into the upper end opening 213 of the radioactively contaminated water storage case 21 in the vertical direction. Can be put in. Therefore, the radioactive substance adsorption filter 1 that adsorbs a large amount of radioactive substance H and the new radioactive substance adsorption filter 1 can be more easily and safely exchanged from the upper end opening 213 of the radioactively contaminated water storage case 21. .

  INDUSTRIAL APPLICABILITY The present invention can be used as a decontamination treatment method and treatment apparatus for radioactively contaminated water contaminated with radioactive substances such as cesium.

DESCRIPTION OF SYMBOLS 1 Radioactive material adsorption filter 2 Filter unit 3 Contaminated water tank 4 Relay filtration apparatus 5 Intermediate receiving tank 6 Auxiliary tank 10 Treatment apparatus 11 Adsorbent 12 Fiber sheet 13 Frame 21 Radioactive contaminated water storage case 22 Lid member 23 Cylinder member 52 Return Pipe line 121 Outer edge 122 Fiber yarn 123 Polymer protective film 212 Output port 213 Upper end opening 521 Return port 522 Feed pump H Radioactive substance HW Radioactive contaminated water T Bamboo charcoal

Claims (9)

Radioactive contaminated water in which radioactive polluted water is passed through a radioactive substance adsorbing filter to which an adsorbent that adsorbs radioactive substances is fixed, and the radioactive substance contained in the radioactive contaminated water is adsorbed on the adsorbent and decontaminated. The decontamination processing method of
The radioactive substance adsorbing filter is combustible on a flat membrane-like combustible fiber sheet in which the outer edge is held by a combustible frame and the surface of each fiber yarn is coated with a polymer protective film. A decontamination treatment method for radioactively contaminated water, characterized in that an adsorbent is fixedly formed while being exposed from the polymer protective film. A method for decontaminating radioactively contaminated water according to claim 1,
The adsorbent is made of bamboo charcoal that has been pulverized into fine particles by pulverizing to a size not less than the fiber yarn diameter of the fiber sheet and not less than the thickness of the polymer protective film. Processing method. A method for decontamination treatment of radioactively contaminated water according to claim 1 or claim 2,
The radioactive substance adsorbing filter allows the radioactive contaminated water to permeate at a normal pressure a plurality of times. A decontamination method for radioactively contaminated water according to any one of claims 1 to 3,
The polymer protective film is formed by kneading the adsorbent in a solvent solution in which cellulose ether is dissolved in an alkaline aqueous solution, coating the fiber sheet, and then drying it. Decontamination treatment method. It is a decontamination processing apparatus used for the decontamination processing method of the radioactive contamination water described in any one of Claims 1 thru | or 4,
A contaminated water tank that stores the radioactively contaminated water, a relay filtration device that circulates the radioactively contaminated water pumped from the contaminated water tank to remove foreign matter, and the radioactive contamination that has been filtered by the relay filter device An intermediate receiving tank for storing water; and a plurality of filter units to which the radioactive substance adsorbing filter for adsorbing the radioactive substance by circulating the radioactively contaminated water stored in the intermediate receiving tank a plurality of times is detachably mounted; And a decontamination processing apparatus. In the decontamination processing apparatus according to claim 5,
The decontamination processing apparatus, wherein the filter unit is connected in parallel to the intermediate receiving tank. In the decontamination processing apparatus according to claim 5 or 6,
The radioactive contaminated water discharged from the output port of the filter unit is temporarily stored in the return line of the radioactive contaminated water connecting the output port of the filter unit and the return port of the intermediate receiving tank. A decontamination processing apparatus comprising an auxiliary tank placed below the output port of the filter unit and returning the radioactively contaminated water stored in the auxiliary tank to the intermediate receiving tank via a feed pump . In the decontamination processing apparatus according to any one of claims 5 to 7,
In the filter unit, the radioactive substance adsorption filter is stood and accommodated in a vertical direction, and the radioactive substance adsorption filter is provided with a radioactive contamination water storage case that allows the radioactive substance adsorption filter to pass in the horizontal direction.
A decontamination processing apparatus, wherein a lid member formed so that the radioactive substance adsorption filter can be inserted and removed is attached to an upper end opening of the radioactively contaminated water storage case. In the decontamination processing apparatus according to claim 8,
The lid member is connected to a cylinder member formed to be extendable in the vertical direction, and the cylinder member is attached to the radioactively contaminated water storage case so as to be rotatable in the horizontal direction. Processing equipment.

Images