JP2015179036A - Radioactive substance adsorbent, radioactive substance adsorption cartridge, and monitoring device for radioactive substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radioactive substance adsorbent capable of improving decontamination efficiency of a radioactive substance included in environment and in suspension liquid.SOLUTION: A radioactive substance adsorbent 3 is porous base material 31 where a zinc-iron cyano-complex particle is held by ethylene-acetate copolymer resin.

Description

  The present invention relates to a radioactive substance adsorbent, a radioactive substance adsorption cartridge, and a radioactive substance monitoring apparatus.

For example, as a radioactive substance adsorbent capable of adsorbing a radioactive substance such as ¹³⁴ Cs and ¹³⁷ Cs, there is an iron cyano complex such as Prussian blue. This radioactive material adsorbent is used in environments such as atmospheric gases and liquids such as water present in seawater, rivers, lakes, ponds, waterways, springs, etc., and suspended in earth and sand and incinerated ash. In order to decontaminate radioactive material contained in the liquid, or concentrate the radioactive material contained in the sample solution collected from the environment and suspension, and measure the concentration and nuclide of the concentrated radioactive material It is used for monitoring (monitoring).

  And in order to make it easy to collect | recover the iron cyano complex which adsorb | sucked the radioactive substance from the environment and suspension liquid, as disclosed, for example in patent document 1, iron cyano complex with a binder on porous substrates, such as a nonwoven fabric, is carried out. Radioactive material adsorbents carrying complex particles have been studied. Patent Document 1 discloses a binder containing a vinyl chloride component as a binder suitable for supporting iron cyano complex particles on a porous substrate.

JP2013-53389A

  With reference to Patent Document 1, the present inventors have studied a radioactive material adsorbent in which iron cyano complex particles are supported on a porous substrate by a binder. However, some of the radioactive material adsorbents studied have a reduced ability to adsorb the radioactive material by the iron cyano complex. In such a radioactive material adsorbent, the radioactive material is sufficiently removed from the environment and suspension. I sometimes couldn't dye. In addition, some of the radioactive material adsorbents that have been studied are those in which iron cyano complex particles easily fall off. In such radioactive material adsorbents, used iron cyano complexes remain in the environment and in suspension. In some cases, it could not be recovered sufficiently.

  As described above, the fact that the iron cyano complex adsorbing the radioactive substance from the environment and the suspension cannot be sufficiently recovered means that the radioactive substance contained in the environment and the suspension cannot be sufficiently decontaminated. . In addition, it has been a cause of increasing the time required for monitoring radioactive substances contained in the environment and suspension.

  Therefore, the radioactive substance adsorbent that can improve the decontamination efficiency of radioactive substances contained in the environment and suspension, and can reduce the time required for monitoring the radioactive substances contained in the environment and suspension, There is a need for a radioactive material adsorption cartridge and a radioactive material monitoring device.

  The radioactive substance adsorbent according to one aspect of the present invention includes a porous substrate on which zinc-iron cyano complex particles are supported by an ethylene-vinyl acetate copolymer resin.

  The radioactive substance adsorption cartridge which concerns on another side surface of this invention is equipped with said radioactive substance adsorption material.

  A radioactive substance monitoring device according to still another aspect of the present invention includes the cartridge described above.

  The present inventors have found that in a radioactive material adsorbent in which zinc-iron cyano complex particles are supported on a porous substrate by an ethylene-vinyl acetate copolymer resin, the zinc-iron cyano complex particles are difficult to drop off. It was. Therefore, the radioactive substance adsorbent, the radioactive substance adsorption cartridge, and the radioactive substance monitoring device can improve the decontamination efficiency of the radioactive substance contained in the environment and in the suspension. The time required for monitoring radioactive materials contained in can be shortened.

  ADVANTAGE OF THE INVENTION According to this invention, the decontamination efficiency of the radioactive substance contained in the environment and suspension can be improved, and the time required for monitoring of the radioactive substance contained in the environment and suspension can be shortened. .

It is a perspective view which shows roughly the structure of the radioactive substance adsorbent which concerns on this embodiment. It is a perspective view which shows roughly the structure of a radioactive substance adsorption cartridge provided with the radioactive substance adsorption material of FIG. It is a perspective view which shows the structure of the accommodating part of FIG. 2 roughly. It is a figure showing roughly a monitoring device concerning this embodiment. It is a figure which shows roughly the modification of the monitoring apparatus of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

  FIG. 1 is a perspective view schematically showing the configuration of the radioactive substance adsorbent according to the present embodiment. As shown in FIG. 1, the radioactive substance adsorbing material 3 is a filter for adsorbing radioactive substances, and is a porous group in which zinc-iron cyano complex particles are supported by an ethylene-vinyl acetate copolymer resin. A material 31 is provided. In this embodiment, since the radioactive substance adsorbing material 3 used as a roll filter for the roll filter device is mentioned as an example, the radioactive substance adsorbing material 3 has a shape processed so as to be wound. .

  The shape of the radioactive substance adsorbing material 3 can be appropriately adjusted so as to have an outer shape suitable for use of the radioactive substance adsorbing material 3, and is not limited. The radioactive substance adsorbing material 3 can also be used as a flat sheet. Moreover, the shape of the radioactive substance adsorbent 3 may be, for example, a shape obtained by punching or cutting a rectangular shape such as a round shape, an oval shape, or a square shape. Moreover, the shape of the radioactive substance adsorbing material 3 may be, for example, a pleated folded shape, or a shape processed so as to follow the shape of the laying target surface of the radioactive substance adsorbing material 3.

  The porous substrate 31 mainly plays a role of forming a skeleton of the radioactive substance adsorbing material 3. The kind of the porous substrate 31 is appropriately selected. Examples of the porous base material 31 include fabrics such as non-woven fabrics, woven fabrics, and knitted fabrics, single materials such as porous films and porous foams, a plurality of single materials stacked, and a plurality of types of materials. Laminates can be used.

  The material constituting the porous substrate 31 is, for example, a polyolefin resin (for example, a polyolefin resin polyethylene, polypropylene, polymethylpentene or the like having a structure in which a part of hydrocarbon is substituted with a halogen such as fluorine or chlorine or a cyano group). , Ethylene-vinyl acetate copolymer resin, styrene resin, polyvinyl alcohol resin, polyether resin (eg, polyether ether ketone, polyacetal, modified polyphenylene ether, aromatic polyether ketone, etc.), polyester resin (eg, , Polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate, polyarylate, wholly aromatic polyester resin, etc. , Polyimide resins, polyamideimide resins, polyamide resins (for example, aromatic polyamide resins, aromatic polyetheramide resins, nylon resins, etc.), resins having a nitrile group (for example, polyacrylonitrile, etc.), urethane resins, epoxy Resin, polysulfone resin (for example, polysulfone, polyethersulfone, etc.), fluorine resin (for example, polytetrafluoroethylene, polyvinylidene fluoride, etc.), cellulose resin, polybenzimidazole resin, acrylic resin (for example, acrylic resin) Such as polyacrylonitrile resins copolymerized with acid esters or methacrylate esters, modacrylic resins copolymerized with acrylonitrile and vinyl chloride or vinylidene chloride, etc.). That.

  In addition, these organic polymers may consist of either a linear polymer or a branched polymer. The organic polymer may be a block copolymer or a random copolymer. The organic polymer may have any three-dimensional structure and crystallinity, and is not particularly limited. Furthermore, what mixed the multi-component organic polymer may be used. In particular, the porous base material 31 is made of a polyolefin-based resin because it is easy to provide the radioactive material adsorbent 3 in which the zinc-iron cyano complex particles are not easily decomposed during use because they are excellent in weather resistance and difficult to fall off. It is preferable that the porous base material 31 is made of polypropylene.

  The constituent fibers of the fabric are spun by, for example, melt spinning method, dry spinning method, wet spinning method, direct spinning method (melt blow method, spun bond method, electrostatic spinning method, spinning stock solution and gas flow are discharged in parallel. A method (for example, a method disclosed in Japanese Patent Application Laid-Open No. 2009-287138), a method of extracting a fiber having a small fiber diameter by removing one or more kinds of resin components from a composite fiber, It can be obtained by a known method such as a method for obtaining a fresh fiber.

  The fiber constituting the fabric may be composed of one kind of organic polymer or may be composed of a plurality of kinds of organic polymers. The fiber composed of a plurality of types of organic polymers may be generally referred to as a composite fiber, for example, a core-sheath type, a sea-island type, a side-by-side type, an orange type, a bimetal type, or the like.

  The fabric may contain adhesive fibers as constituent fibers. By including adhesive fibers, the strength of the fabric can be improved. The type of the adhesive fiber is appropriately selected. For example, a core-sheath type adhesive fiber, a side-by-side type adhesive fiber, or an all-melt type adhesive fiber can be adopted.

  Further, the fabric may include a modified cross-section fiber as a constituent fiber in addition to a fiber having a circular cross section and an elliptical fiber. In addition, as the irregular cross-section fiber, for example, a polygonal shape such as a triangular shape, an alphabetic character shape such as a Y shape, an irregular shape, a multi-leaf shape, a symbolic shape such as an asterisk shape, or a combination of these shapes The fiber which has fiber cross sections, such as the shape which was made.

  When the fabric is a woven fabric or a knitted fabric, it is prepared by weaving or knitting the fibers prepared as described above. When the fabric is a non-woven fabric, for example, a dry non-woven fabric in which the fibers are intertwined into a non-woven fabric by being applied to a card device or an air lay device, etc. Wet nonwoven fabrics, and nonwoven fabrics obtained by collecting fibers while spinning fibers using a direct spinning method. The direct spinning method includes a melt blow method, a spunbond method, an electrostatic spinning method, a method of spinning by spinning a spinning stock solution and a gas flow in parallel (for example, a method disclosed in JP 2009-287138 A), and the like. .

  As a method for performing at least one of entanglement and integration of fibers constituting a fabric, for example, a method of entanglement with a needle or a water flow, a method of integrating fibers with a binder, or a fiber provided with a thermoplastic resin Is included, a method in which the thermoplastic resin is melted by heat treatment and the fibers are integrated is exemplified. In addition, as a method of heat-processing, the method of heating and pressurizing with a calender roll, the method of heating with a hot air dryer, the method of irradiating infrared rays under no pressure, the method of melting a thermoplastic resin fiber, etc. may be used.

  There exists a tendency which can provide the radioactive substance adsorbent which is excellent in the adsorption | suction performance of a radioactive substance, so that the fineness of the fiber which comprises a fabric is thin. Therefore, the fineness of the fibers constituting the fabric is, for example, preferably 50 dtex or less, and more preferably 30 dtex or less. Further, the lower limit value of the fineness of the fibers constituting the fabric is adjusted as appropriate, but it is realistic that it is 0.1 dtex or more.

  Moreover, the fiber length of the fiber which comprises a fabric is not specifically limited, However, 0.5-150 mm may be sufficient and a continuous fiber may be sufficient depending on the manufacturing method of a fiber. The fabric may include two or more types of fibers that differ in at least one of fineness and fiber length.

  In addition, the preparation method of the porous foam which has a porous film and liquid permeability is selected suitably, and is not limited. The porous film and the porous foam can be prepared by a known method such as casting a molten organic resin into a mold and performing foaming treatment.

  Various configurations (for example, thickness, basis weight, apparent density, etc.) of the porous base material 31 are excellent in the adsorption performance of the radioactive substance, and can provide the radioactive substance adsorbent in which the zinc-iron cyano complex particles are difficult to fall off. , Adjusted as appropriate.

Basis weight of the porous substrate 31 is preferably from 30~3000g / ^{m 2,} more preferably from 50 to 1000 g / ^{m 2.} If the basis weight of the porous base material 31 is less than 30 g / m ² , the strength of the porous base material 31 tends to be low, and it tends to break during handling. When the basis weight of the porous base material 31 exceeds 3000 g / m ² , the weight increases and the handleability decreases, and the thickness of the porous base material 31 tends to be thick and difficult to obtain a desired thickness. There is. The “weight per unit area” refers to the mass per 1 m ^{2 on} the main surface, and the main surface refers to a surface having a large area.

Moreover, it is preferable that the thickness of the porous base material 31 is 0.1-100 mm, and 0.1-0.5 mm is more preferable. If the thickness of the porous base material 31 is less than 0.1 mm, the apparent density of the porous base material 31 becomes too high, and the contact area with the radioactive substance tends to decrease. When the thickness of the porous base material 31 exceeds 100 mm, the density of the porous base material 31 becomes too low, and the strength of the porous base material 31 tends to decrease or the handleability tends to decrease. “Thickness” refers to a value measured under a load of 0.5 g / cm ² .

Further, apparent density of the porous substrate 31 is preferably a 0.005 to 0.5 / cm ^3, more preferably 0.007~0.04g / cm ^3. When the apparent density of the porous base material 31 is less than 0.005 g / cm ³ , the strength of the porous base material 31 tends to be lowered, and the handleability tends to be lowered. If the apparent density of the porous base material 31 exceeds 0.5 g / cm ³ , the contact area with the radioactive substance tends to decrease.

The zinc-iron cyano complex plays a role as a radioactive substance adsorbent for adsorbing a radioactive substance. The zinc-iron cyano complex has the general formula:
_Ap Zn [Fe (CN) ₆ ] _X
(In the formula, A is an atom derived from a cation, p is 0 to 0.8, and x is 0.3 to 0.7)
As long as it is capable of adsorbing a radioactive substance, its crystal structure is not limited and may be cubic, trigonal, tetragonal, or the like.

Fe (CN) ₆ is a hexacyanoiron ion, part of which may be substituted with water or hydroxide ion, and a part of the coordination number (in this case 6) is changed to 2-8. It may be. A is, for example, an alkali ion such as potassium ion, lithium ion, sodium ion, rubidium ion, or ammonium ion, and water may be included in the crystal. In particular, A is preferably a sodium ion, and more preferably a potassium ion. Furthermore, a ligand or the like may be present on the surface of the zinc-iron cyano complex particle for the purpose of controlling dispersibility. In addition, when the cation A is excessively contained as a counter ion of other anions such as chloride (ACl), sulfate (A ₂ SO ₄ ), and nitrate (ANO ₃ ), other anions are used. The amount contained as a counter ion with ions is not included in p.

  As the zinc-iron cyano complex, for example, particles described in JP2012-72015A can be used. The primary average particle diameter of the zinc-iron cyano complex particles is preferably 1000 nm or less, more preferably 500 nm or less, and particularly preferably 300 nm or less.

  The primary particle diameter refers to the diameter of the primary particle, and the diameter is calculated as the diameter of the circle corresponding to the projected area of each particle from the image of the diameter of the particle (ultrafine particles obtained by observation with an electron microscope). Value). The average particle size means an arithmetic average value of values obtained by measuring the particle size of at least 30 particles as described above, unless otherwise specified. When it is difficult to perform the measurement, the average particle diameter is calculated from the half-value width of the signal from the X-ray diffraction (XRD) measurement of the particle, or from the value obtained from the dynamic light scattering measurement. The average particle size is calculated. In some cases, a ligand or the like may be present on the particle surface. In this case, the primary particle size is the particle size excluding the ligand.

  Particles granulated into secondary particles as zinc-iron cyano complex particles may be used. In this case, secondary particles having an average particle diameter of 10 μm to 10 mm may be used, and secondary particles having an average particle diameter of 20 μm to 5 mm may be used.

  The shape of the zinc-iron cyano complex particles can be appropriately selected from, for example, a spherical shape (substantially spherical or true spherical shape), a fibrous shape, a needle shape, a flat plate shape, a polygonal cubic shape, a feather shape, and the like.

  The ethylene-vinyl acetate copolymer resin serves as a binder for bonding the porous base material 31 and the zinc-iron cyano complex particles, and serves to support the zinc-iron cyano complex particles on the porous base material 31. . The kind of ethylene-vinyl acetate copolymer resin is appropriately selected so as to provide the radioactive material adsorbent 3 in which the zinc-iron cyano complex particles do not easily fall off. The ethylene-vinyl acetate copolymer resin is a concept including a ternary copolymer resin in addition to the ethylene-vinyl acetate binary copolymer resin. As the ternary copolymer resin, for example, ethylene-vinyl acetate-vinyl versatate copolymer resin, ethylene-vinyl acetate-acrylic ester copolymer resin, ethylene-vinyl acetate-vinyl chloride copolymer resin, etc. are used. Can be.

  It is only necessary that zinc-iron cyano complex particles are supported on the porous substrate 31 by the presence of the ethylene-vinyl acetate copolymer resin. This support may be a binder that exists in the form of particles or a film on the surface of the porous base material 31 and may be formed by a binder containing an ethylene-vinyl acetate copolymer resin. The aspect comprised by the ethylene-vinyl acetate copolymer resin contained in the component which comprises the quality base material 31 may be sufficient.

  In the binder and in the components constituting the porous base material 31, there are resins other than the ethylene-vinyl acetate copolymer resin (hereinafter sometimes referred to as “non-ethylene-vinyl acetate copolymer resin”). May be present. The kind of non-ethylene-vinyl acetate copolymer resin is appropriately selected. As the non-ethylene-vinyl acetate copolymer resin, the organic polymer mentioned as the material constituting the porous substrate 31 can be used. Specific examples include acrylic resin, polyethylene resin, vinyl chloride-ethylene multi-component copolymer resin, and the like.

  The mass ratio of the ethylene-vinyl acetate copolymer resin contained in the binder is appropriately adjusted to such an extent that the radioactive material adsorbent 3 that is less likely to drop off can be provided. Ethylene-vinyl acetate copolymer resin: Non-ethylene-vinyl acetate copolymer resin may be, for example, 99% by mass: 1% by mass to 10% by mass: 90% by mass, and 90% by mass: 10% by mass to 50 mass%: It may be 50 mass%. In particular, a binder in which the adhesive component carrying the zinc-iron cyano complex particles on the porous base material 31 is made of only an ethylene-vinyl acetate copolymer resin is preferable because it can provide the radioactive material adsorbent 3 that is most unlikely to drop off.

  The binder may contain functional components such as a crosslinking agent (for example, a melamine resin, an oxazoline resin, an isocyanate resin, etc.), a surfactant, an oil repellent, a penetrating agent, a flame retardant, and the like.

The basis weight of the radioactive substance adsorbing material 3 is not particularly limited. The basis weight of the radioactive material adsorbent 3 may be a 10~3000g / ^{m 2,} may be 20~1000g / ^{m 2.} Moreover, the thickness of the radioactive substance adsorbent 3 is adjusted as appropriate, and is not limited. The thickness of the radioactive substance adsorbing material 3 may be, for example, 0.01 to 100 mm, or 0.1 to 50 mm.

Although the mass of the zinc-iron cyano complex particles carried on the radioactive substance adsorbing material 3 is adjusted as appropriate, the adsorbing performance of the radioactive substance exhibited by the radioactive substance adsorbing material 3 is excellent per 1 m ² of the radioactive substance adsorbing material. The supported mass is preferably 1 g or more. Since the adsorption performance of the radioactive substance is better when the loading mass of the zinc-iron cyano complex particles is larger, the loading mass is preferably 3 g or more per 1 m ² of the radioactive substance adsorbent, and more preferably 4 g or more. Most preferred. On the other hand, there is no upper limit to the mass of the zinc-iron cyano complex particles carried on the radioactive material adsorbent 3. However, if the mass of the supported zinc-iron cyano complex particles is too heavy, the zinc-iron cyano complex particles may be peeled off from the radioactive material adsorbent 3, so that it is 20 g or less per 1 m ² of the radioactive material adsorbent. Thus, the radioactive material adsorbent 3 preferably supports zinc-iron cyano complex particles.

  The mass ratio of the ethylene-vinyl acetate copolymer resin and the zinc-iron cyano complex particles contained in the radioactive material adsorbent 3 is appropriately adjusted so that the zinc-iron cyano complex particles do not easily fall off. The ratio of the mass of the ethylene-vinyl acetate copolymer resin to the mass of the zinc-iron cyano complex particles is preferably 80:20 to 99: 1, more preferably 80:20 to 97: 3, More preferably, it is 80: 20-95: 5.

The method for supporting the zinc-iron cyano complex particles on the porous substrate 31 with the ethylene-vinyl acetate copolymer resin is appropriately selected. As this supporting method, for example,
(1) After immersing the porous substrate 31 in a mixture prepared by mixing zinc-iron cyano complex particles in a binder dispersion or solution containing an ethylene-vinyl acetate copolymer resin, A method of removing the solvent or dispersion medium by drying by heating,
(2) A method of removing the solvent or dispersion medium by applying or spraying the above-mentioned mixed solution to the porous substrate 31 and then naturally drying or heat drying.
(3) A method in which a binder and zinc-iron cyano complex particles are imparted to the porous base material 31, and the binder is heated to melt the binder, followed by cooling.
(4) A method of cooling after applying a molten binder to the porous base material 31 and attaching zinc-iron cyano complex particles on the molten binder,
(5) Zinc-iron cyano complex particles were imparted to the porous base material 31 containing ethylene-vinyl acetate copolymer resin as a constituent component and heated to melt the ethylene-vinyl acetate copolymer resin. After cooling,
Etc.

  Note that the heating method can be appropriately selected. As a heating method, for example, a method of heating and pressurizing with a calender roll, a method of heating with a hot air dryer, a method of melting thermoplastic resin fibers by irradiating infrared rays under no pressure can be used. The porous substrate 31 can carry zinc-iron cyano complex particles by heat drying by the above-described method and softening or melting the ethylene-vinyl acetate copolymer resin.

  In particular, when the porous base material 31 has air permeability or liquid permeability, after immersing the porous base material 31 in the mixed liquid of (1), the solvent or dispersion medium is removed by natural drying or heat drying. It is preferable that zinc-iron cyano complex particles are supported on the porous substrate 31 by adopting the method. In this case, zinc-iron cyano complex particles can be supported even inside the porous substrate 31, and the radioactive substance can be adsorbed efficiently.

  The method for drying by heating is not particularly limited. However, when the porous substrate 31 has air permeability or liquid permeability, the structure is maintained and the zinc-iron cyano complex particles are brought into contact with the radioactive substance. It is preferable to dry with a hot air drier so as to increase opportunities.

  The radioactive substance adsorbent 3 prepared as described above can be used as it is. Moreover, the radioactive substance adsorbing material 3 may be reinforced by laminating a support such as a separately prepared fabric, film, or foam so that handling and performance are improved, such as improving strength and filtration performance.

  Next, a radioactive substance adsorption cartridge using a radioactive substance adsorbent will be described. FIG. 2 is a perspective view schematically showing the configuration of the radioactive substance adsorption cartridge according to the present embodiment. As shown in FIG. 2, the radioactive substance adsorption cartridge 1 is a radioactive substance adsorption cartridge for a radioactive substance monitoring device, and includes a storage portion 2 and a radioactive substance adsorption material 3.

  FIG. 3 is a perspective view schematically showing the configuration of the accommodating portion 2. The accommodating portion 2 is a container that can accommodate the radioactive substance adsorbing material 3. In the present embodiment, the accommodating portion 2 is a frame that accommodates the roll filter, and includes a cylindrical member 21, a first end plate 22, and a second end plate 23. The cylindrical member 21 is a hollow cylindrical porous member, and has one end portion 21a, the other end portion 21b, an outer peripheral surface 21c, and an inner peripheral surface 21d. One end portion 21a of the cylindrical member 21 is one end portion in the axis X direction, and has a circular opening with the axis X as the center. The other end 21b of the cylindrical member 21 is the other end in the direction of the axis X, and has a circular opening centered on the axis X. A hollow portion extends along the axis X from the opening of the one end 21a to the opening of the other end 21b.

  The tubular member 21 is provided with a plurality of water passage holes 21e penetrating from the outer peripheral surface 21c to the inner peripheral surface 21d. The shape and size of the water passage hole 21e and the number and arrangement of the water passage holes 21e are adjusted as appropriate. For example, the water passage hole 21e has a long oval shape in the circumferential direction. , And a shape arranged at regular intervals along the axis X direction, and arranged at regular intervals along the circumferential direction. The cylindrical member 21 is comprised from the organic polymer which can comprise a cloth, a metal, wood, a silicone resin, etc.

  The first end plate 22 has a disk shape with the axis X of the cylindrical member 21 as an axis, and has a circular opening 22 a centered on the axis X. The first end plate 22 is provided at one end 21 a of the cylindrical member 21. The cylindrical member 21 and the first end plate 22 are bonded by, for example, welding by welding a contact portion between the cylindrical member 21 and the first end plate 22 or by bonding via a hot melt resin. Is done. In addition, a screw thread is provided at one end 21a of the cylindrical member 21, a screw receiver is provided at a joint portion of the first end plate 22 with the cylindrical member 21, and the cylindrical member 21 and the first end are fitted by screwing. One end plate 22 may be joined. A screw receiver may be provided at one end 21 a of the cylindrical member 21, and a screw thread may be provided at the first end plate 22. Moreover, a fitting part is provided in the one end part 21a of the cylindrical member 21, a fitting part is provided in the junction part with the cylindrical member 21 of the 1st end plate 22, and this fitting part is fitted. The cylindrical member 21 and the first end plate 22 may be joined together. This fitting part is a recessed part or a convex part, for example. The first end plate 22 is made of an organic polymer, metal, wood, silicone resin, or the like that can form a cloth.

  The second end plate 23 has a disk shape with the axis X of the cylindrical member 21 as an axis. Note that, similarly to the first end plate 22, the second end plate 23 may have a circular opening (not shown) centered on the axis X. The second end plate 23 is provided at the other end 21 b of the cylindrical member 21. The joining of the tubular member 21 and the second end plate 23 is performed in the same manner as the joining of the tubular member 21 and the first end plate 22. The second end plate 23 is made of an organic polymer, metal, wood, silicone resin, or the like that can form a cloth.

  In the accommodating part 2, the 1st end plate 22, the cylindrical member 21, and the 2nd end plate 23 are coaxially arranged in the axis | shaft X direction in that order. Further, the opening 22a of the first end plate 22 and the hollow portion of the cylindrical member 21 are coaxially connected. When the second end plate 23 has an opening, the opening 22a of the first end plate 22, the hollow portion of the cylindrical member 21, and the opening of the second end plate 23 are coaxially connected. Yes.

  In the radioactive substance adsorbing cartridge 1 of FIG. 2, the length of the radioactive substance adsorbing material 3 in the axis X direction is appropriately adjusted, but the environmental water and the sample liquid are transferred from one end 3 a and the other end 3 b of the radioactive substance adsorbing material 3. In order to prevent water from passing through the inner peripheral surface 3d, one end 3a of the radioactive substance adsorbing material 3 contacts the first end plate 22, and the other end 3b of the radioactive substance adsorbing material 3 contacts the second end plate 23. It may be a possible length.

  The storage unit 2 may be a variety of frames and containers that can store the radioactive substance adsorbing material 3. For example, a tubular container including a syringe container, a marinelli container, or a U8 container, a frame with a frame shape, and a depth filter. It may be a frame or the like. The syringe container may be a container in which a disk-shaped radioactive substance adsorbing material can be sandwiched between a pair of top-shaped plastic moldings provided with inlets or outlets at both ends. Further, the tubular container has a disk-shaped radioactive substance adsorbent laminated body or a wound scroll-shaped radioactive substance adsorbent 3 inside a pipe provided with an inlet or outlet at one or both ends. The container which can be accommodated may be sufficient.

  When the accommodating part 2 is a frame for a depth filter, the aspect of the radioactive substance adsorbing material 3 accommodated is a depth type in which the radioactive substance adsorbing material 3 is wound around the core material in multiple layers, and around the core material. A pleat type in which the radioactive material adsorbent 3 pleated into a zigzag shape is wound may be used. Further, in order to prevent the radioactive substance adsorbing material 3 accommodated in the depth filter frame from being deformed during use, the end of the core material is surrounded so as to surround the outer main surface of the wound radioactive substance adsorbing material 3. The part may be provided with at least one of an end plate and a cover material having a plurality of holes. Note that the end plate and the cover material can be composed of the same components as the core material, and the core material, the end plate and the cover material can be separated, or the respective members can be bonded and integrated. Good.

  When the housing 2 is a depth filter frame, the radioactive substance adsorbing cartridge 1 generally has a radioactive substance adsorbing material 3 that is filtered from the outer main surface side of the radioactive substance adsorbing material 3 to the core material side. It may be used so as to pass through, or may be used so that the object to be filtered passes through the radioactive substance adsorbing material 3 from the core material side to the external main surface side of the radioactive substance adsorbing material. When the radioactive substance adsorbing cartridge 1 is used in such a manner that the object to be filtered passes through the radioactive substance adsorbing material 3 from the core material side to the outer main surface side of the radioactive substance adsorbing material, it is trapped in the radioactive substance adsorbing material 3. It is possible to prevent non-dissolved components (hereinafter referred to as “SS component”) such as sand to which radioactive material is attached from coming out of the radioactive material adsorption cartridge 1 even when the radioactive material adsorbent 3 falls off.

  Next, a monitoring device using a radioactive substance adsorption cartridge will be described. FIG. 4 is a diagram schematically illustrating the monitoring device according to the present embodiment.

  As shown in FIG. 4, the monitoring device 10 is in the environmental water W1 which is water contained in the environment (for example, water existing in seawater, rivers, lakes, ponds, waterways, springs, etc.) or suspension. Is a device for adsorbing and concentrating the radioactive substance in the radioactive substance adsorbing material 3 provided in the radioactive substance adsorbing cartridge 1, and enables decontamination and monitoring of the radioactive substance contained in the environmental water W1. The monitoring device 10 includes a radioactive substance adsorption cartridge 1, a flow meter 11, a pump 12, and a liquid passage 13.

  The flow meter 11 is a device that measures the amount of environmental water flowing through the monitoring device 10. The pump 12 is a device for passing the environmental water W1 through the monitoring device 10. The liquid flow pipe 13 is a pipe through which the environmental water W1 flows, and includes a liquid flow pipe 13a, a liquid flow pipe 13b, a liquid flow pipe 13c, and a liquid flow pipe 13d. The liquid passage 13a connects between the environmental water W1 and the radioactive substance adsorption cartridge 1, the liquid passage 13b connects between the radioactive substance adsorption cartridge 1 and the flow meter 11, and the liquid passage 13c is connected to the flow meter 11. And the pump 12 are connected to each other, and the fluid passage 13d connects the pump 12 and the environmental water W1.

  A method of using the monitoring device 10 will be described. First, one end of the liquid flow pipe 13a is installed in the environmental water W1. Instead of this, the radioactive substance adsorption cartridge 1 may be installed in the environmental water W1 without using the liquid passing pipe 13a. Then, the pump 12 is operated to supply the environmental water W1 to the radioactive substance adsorbing cartridge 1 through the liquid pipe 13a, and the environmental water W1 is passed through the radioactive substance adsorbing material 3 provided in the radioactive substance adsorbing cartridge 1. . At this time, the radioactive substance dissolved in the environmental water W1 is selectively adsorbed on the zinc-iron cyano complex particles supported on the radioactive substance adsorbent 3, thereby being adsorbed on the radioactive substance adsorbent 3 and concentrated. To do.

  Next, the environmental water W1 that has passed through the radioactive substance adsorbing material 3 is allowed to pass through the flow meter 11 through the liquid passing pipe 13b. Further, the environmental water W1 that has passed through the flow meter 11 is allowed to pass through the pump 12 via the liquid passage 13c. And the environmental water W1 which passed the pump 12 is discharged | emitted from the monitoring apparatus 10 through the liquid pipe 13d.

  After supplying the specific amount of environmental water W1 to the monitoring device 10, the radioactive material adsorbing cartridge 1 is removed from the monitoring device 10 and the used radioactive material adsorbing material 3 is collected, so that the radioactive material contained in the environmental water W1 is recovered. Decontamination is performed.

You may monitor the radioactive substance in environmental water W1 by using the collect | recovered radioactive substance adsorbent 3 for a detector. The method is appropriately selected. For example,
(1) When measuring the concentration and nuclide of the radioactive substance dissolved in the SS component and the environmental water W1, a method of using the collected radioactive substance adsorbent 3 as it is to the detector,
(2) When measuring only the concentration and nuclide of the radioactive substance dissolved in the environmental water W1, the collected radioactive substance adsorbent 3 is washed with water or ultrasonically so as to recover the collected radioactive substance adsorbent. A method of using the detector after removing SS from 3;
(3) On the outer peripheral surface of the radioactive material adsorbent 3, a separately prepared fabric is provided as at least one of the reinforcing material layer and the prefilter layer, and the concentration and nuclide of the radioactive material dissolved in the environmental water W1. In the case where only the measurement is performed, a separately prepared fabric is removed from the collected radioactive substance adsorbent 3, thereby removing the SS component from the collected radioactive substance adsorbent 3 and then providing the detector,
The radioactive material adsorbent 3 is analyzed by any one of the methods.

  The concentration of the radioactive substance dissolved in the environmental water W1 is the amount of the environmental water W1 supplied to the radioactive substance adsorption cartridge 1 by using the amount of radiation (Bq) in the radioactive substance adsorbed by the radioactive substance adsorbing material 3. It can be calculated from the concentration (Bq / L) calculated by dividing by (L).

  As described above, in the radioactive material adsorbent 3, since the zinc-iron cyano complex particles are supported on the porous base material 31 by the ethylene-vinyl acetate copolymer resin, the zinc-iron cyano complex particles fall off. It was found difficult. Therefore, the radioactive substance adsorbent 3, the radioactive substance adsorption cartridge 1, and the radioactive substance monitoring device 10 can improve the decontamination efficiency of the radioactive substance contained in the environment and in the suspension. The time required for monitoring radioactive substances contained in the suspension can be shortened.

  In addition, the monitoring device 10 makes it possible to monitor the radioactive material dissolved in the environmental water W1 in distinction from the total amount of radioactive material including SS, and simplifies the monitoring and measurement time of the radioactive material in the environmental water. Can be shortened. For example, even if it is a radioactive substance of low concentration less than 0.3 Bq / L (for example, radioactive cesium), measurement time is not required.

  FIG. 5 is a diagram schematically illustrating a modified example of the monitoring device. As shown in FIG. 5, the monitoring device 10 </ b> A is different from the monitoring device 10 described above in that it further includes a tank 14, and the other configuration is the same as that of the monitoring device 10. That is, in the monitoring apparatus 10A, the sample liquid W2 collected from the environment and the suspension is stored in the tank 14, and is discharged from the monitoring apparatus 10A while monitoring the radioactive substance in the sample liquid W2. By returning the sample liquid W2 into the tank 14, the sample liquid W2 in the tank 14 is circulated.

  Even with the above monitoring device 10A, the same effect as the above-described monitoring device 10 is produced. The monitoring device 10 </ b> A includes a tank 14. For this reason, the sample substance W2 stored in the tank 14 is circulated and supplied to the monitoring device 10A, so that the radioactive substance dissolved in the sample liquid W2 is more reliably concentrated on the radioactive substance adsorbent 3. it can. For this reason, it becomes possible to monitor the radioactive substance dissolved in the sample liquid W2 more accurately.

  The radioactive substance adsorbent, the radioactive substance adsorption cartridge, and the radioactive substance monitoring device according to the present invention are not limited to those described in the above embodiment. For example, the monitoring devices 10 and 10A include one radioactive substance adsorption cartridge 1, but may include a plurality of radioactive substance adsorption cartridges 1.

  Moreover, the monitoring apparatuses 10 and 10A may further include a prefilter for capturing the SS component. This filter is provided on the upstream side of the radioactive substance adsorption cartridge 1 (on the liquid passage 13a). In this case, the SS component, the radioactive water dissolved in the environmental water W1 and the sample liquid W2 can be separately captured, and the environmental water W1 and the sample liquid W2 from which the SS component has been removed are supplied to the radioactive substance adsorption cartridge 1. It becomes possible. The prefilter may be a fabric or a porous film.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention.

(Preparation of non-woven fabric)
A core-sheath type composite fiber (core part: polypropylene resin, sheath part: polyethylene resin, fineness: 0.8 dtex, fiber length: 5 mm) is subjected to wet papermaking, and then dried at 140 ° C. with a hot air dryer to form the sheath part. A nonwoven fabric (weight per unit area: 50 g / m ² ) was prepared by melting and heat sealing.

(Preparation of binder solution)
The following radioactive material adsorbents (A) to (C) and binders (D) to (K) were blended in the mixing ratio (mass%) shown in Table 1 below, respectively, and Example 1 and Comparative Examples 1 to 1 were mixed. A binder solution used in Comparative Example 6 was prepared.
[Radioactive material adsorbent]
(A) Zinc-iron cyano complex particle dispersion (particle size: 50-200 nm, manufactured by Kanto Chemical Co., Ltd., product name: zinc ferrocyanide potassium complex, solid content: 10% by mass)
(B) Bituminous powder (iron cyano complex particles, particle size: 50-100 nm, manufactured by Dainichi Seika, product name: Belence Blue)
(C) Prussian blue nano-dispersion (iron cyano complex particle nano-dispersion, particle size: 10-20 nm, manufactured by Kanto Chemical Co., Ltd., product name: Prussian blue nano-dispersion H, solid content: 10% by mass)
[Binder]
(D) Ethylene-vinyl acetate copolymer resin emulsion (manufactured by Sumitomo Chemical, product name: Sumikaflex 951HQ, solid content: 55% by mass)
(E) Ethylene-vinyl acetate copolymer resin emulsion (manufactured by Sumitomo Chemical, product name: Sumikaflex 752, solid content: 50% by mass)
(F) Acrylic resin emulsion (manufactured by DIC, product name: Boncoat 3218EF, solid content: 50% by mass)
(G) Polyethylene resin dispersion (Mitsui Chemicals, product name: Chemipearl W4005, solid content: 40% by mass)
(H) Vinyl chloride-ethylene multi-component copolymer resin emulsion (manufactured by Sumitomo Chemical, product name: Sumikaflex 850HQ, solid content: 50% by mass)
(I) Polyvinyl chloride resin emulsion (CBC, VYCAR351, solid content: 57% by mass)
(J) Styrene-butadiene copolymer resin emulsion (manufactured by Nippon Zeon, NIPOLLLX421, solid content: 41% by mass)
(K) Water

(Preparation of radioactive material adsorbent)
[Example 1, Comparative Examples 1 to 5]
After applying the prepared binders used in Example 1 and Comparative Examples 1 to 5 using a nip roll to the nonwoven fabric, drying is performed at 130 ° C. with a can dryer, so that the radioactive material adsorbent (weight per unit: 86 g) / M ² , loading mass of radioactive material adsorbent: 4 g / m ² , binder mass (solid content) contained in the radioactive material adsorbent: 32 g / m ² ).

[Comparative Example 6]
The nonwoven fabric was impregnated with the binder liquid used in Comparative Example 6 using a nip roll, and then dried at 130 to 135 ° C. with a can dryer. Thereafter, for the purpose of fixing the bitumen powder, a dye fixing agent (manufactured by Nitto Bo Medical, product name: Dunfix 723, solid content: 35% by mass) is applied by a spray method to give a solid content of 0.06 g / m ^2. , and dried at 130 ° C. at the can dryers, radioactive material adsorbent (basis weight: 86.1 g / ^{m 2,} carrying mass of radioactive material adsorbent: 5 g / ^{m 2,} binder mass containing the radioactive material adsorbent ( Solid content): 31 g / m ² ) was prepared.

(Preparation of cartridge member)
By injection molding molten polypropylene resin,
(1) A cylindrical member (inner diameter 21 mm, outer diameter 28 mm, height 38 mm) having a plurality of water passage holes penetrating from the outer peripheral surface to the inner peripheral surface,
(2) Disc-shaped first plate (outer diameter 62 mm, height 4.5 mm),
(3) a disk-shaped second plate having an opening in the center (inner diameter 23 mm, outer diameter 62 mm, height 4.5 mm),
(4) A cover member having a plurality of water holes penetrating from the outer peripheral surface to the inner peripheral surface (inner diameter 58 mm, outer diameter 61 mm, height 38 mm)
Got.

(Cartridge preparation method)
The radioactive substance adsorbents of Example 1 and Comparative Examples 1 to 6 were cut into a rectangular shape (long side: 1520 mm, short side: 38 mm). After winding this around a cylindrical member, it is inserted and accommodated in the cover member, and the first plate and the second plate are welded to both ends of the cylindrical member and the cover member, so that Example 1 and Comparative Examples 1 to 1 are compared. Each radioactive substance adsorption cartridge equipped with the radioactive substance adsorbent of Example 6 was prepared.

(Measurement method of cyan elution concentration)
Each radioactive substance adsorption cartridge was set in a monitoring device comprising a liquid supply unit, a metering pump, a housing, a flow meter, and a liquid discharge unit. Using this radioactive substance monitoring device, 20 L of water (pH = 6 to 7) in which the concentration of ¹³⁷ Cs was adjusted to 5 Bq was passed through at a rate of 2.5 L / min. 100 ml of water immediately after passing water was collected from the liquid discharge part. The collected water was quantified in terms of the total cyan concentration by a test method according to Japanese Industrial Standards K010238.1.2 and 38.3. The higher the cyan elution concentration, the greater the amount of radioactive material adsorbent that has fallen from the radioactive material adsorption cartridge.

(Measurement method of cesium adsorption rate)
Using a radioactive substance monitoring device equipped with each radioactive substance adsorption cartridge, 20 L of water (pH = 6 to 7) in which the concentration of ¹³⁷ Cs was adjusted to 5 Bq was passed through at a rate of 2.5 L / min. All 20 L of water after passing through was collected in a plastic tank, stirred uniformly, and 2 L was collected. The collected water was put in a 2 L marinelli container, and the ¹³⁷ Cs concentration was measured with a germanium semiconductor detector (manufactured by Seiko EG & G Co., GEM20-70). And using the measured ¹³⁷ Cs density | concentration, the cesium adsorption rate was calculated | required by the following formula.
Cesium adsorption rate ^{(%) = (1- (137} Cs concentration of ¹³⁷ Cs concentration / water flow before after passing water)) × 100

(Measurement method of cesium adsorption rate under acid and alkali (PH dependence))
In the measurement method described in the item (Measurement method of cesium adsorption rate), measurement was performed using a ¹³⁷ Cs test solution adjusted to pH = 3 and pH = 10. Only the radioactive substance adsorbing cartridges of Example 1 and Comparative Example 6 were the targets of this measurement.

(result)
The measurement results of cyan elution concentration and cesium adsorption rate are summarized in Table 2. In Table 2, “−” is written in the results of no measurement.

  According to the results shown in Table 2, the radioactive substance adsorbents of Comparative Example 1, Comparative Example 2, Comparative Example 4 and Comparative Example 6 have a higher cyan elution concentration than the radioactive substance adsorbent of Example 1. The cesium adsorption rate was inferior. Moreover, in the radioactive substance adsorbent of Comparative Example 3, although the cyan elution concentration was the same as that of Example 1, the cesium adsorption rate was inferior. Further, in the radioactive material adsorbent of Comparative Example 5, although the cesium adsorption rate was equivalent to that of Example 1, the cyan elution concentration was high. In addition, in the radioactive substance adsorbent of Comparative Example 5, although the cyan elution concentration was high, the reason why the cesium adsorption rate was equivalent to Example 1 was that the particle diameter of the radioactive substance adsorbent was small and the specific surface area was It can be expensive. Further, in the radioactive material adsorbent of Example 1, the cesium adsorption rate did not decrease even in the strongly acidic or alkaline test solution, whereas in the radioactive material adsorbent of Comparative Example 6, the strongly acidic or alkaline test solution did not decrease. In the test solution, the cesium adsorption rate was lower than that of the test solution with pH = 6-7.

  From the above, it was found that the radioactive substance adsorbent of Example 1 had a low cyan elution concentration and an excellent cesium adsorption rate as compared with the radioactive substance adsorbents of Comparative Examples 1 to 6. That is, in the radioactive substance adsorbent of Example 1, zinc-iron cyano complex particles are supported as a radioactive substance adsorbent on the nonwoven fabric by the ethylene-vinyl acetate copolymer resin, and the radioactive substance adsorbent is difficult to drop off. It was found that the adsorption efficiency of radioactive material (radiocesium) was high regardless of the hydrogen ion concentration of the test solution. Thus, in Example 1, the decontamination efficiency of the radioactive substance (radiocesium) contained in the environment and in the suspension can be improved, and the radioactive substance contained in the environment and in the suspension ( It can be said that the time required for monitoring of radioactive cesium can be shortened.

  According to the radioactive substance adsorbent, the radioactive substance adsorption cartridge, and the radioactive substance monitoring device according to one aspect of the present invention, the decontamination efficiency of the radioactive substance contained in the environment and in the suspension can be improved. In addition, the time required for monitoring the radioactive substance contained in the suspension can be shortened.

  DESCRIPTION OF SYMBOLS 1 ... Radioactive material adsorption cartridge, 2 ... Storage part, 3 ... Radioactive material adsorption material, 10, 10A ... Monitoring apparatus, 31 ... Porous base material, W1 ... Environmental water, W2 ... Sample liquid.

Claims (3)

  A radioactive material adsorbent comprising a porous substrate on which zinc-iron cyano complex particles are supported by an ethylene-vinyl acetate copolymer resin.   A radioactive substance adsorbing cartridge comprising the radioactive substance adsorbing material according to claim 1.   A radioactive substance monitoring device comprising the radioactive substance adsorption cartridge according to claim 2.

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