Tritium adsorbent and tritium-contaminated water treatment system

Abstract

This makes it possible to easily remove tritium from tritium-contaminated water. SOLUTION: In a tritium-contaminated water treatment system S for removing tritium from tritium-contaminated water including tritium water, a drainage path R for draining the tritium-contaminated water from a storage tank 1 storing the tritium-contaminated water is provided, and a filter device 10 equipped with a tritium adsorbent made of a liquid-permeable fiber material having fullerene and / or a fullerene compound is interposed in this drainage path R. A plurality of filter devices 10 are provided in series, and an aeration tank 30 for aerating the tritium-contaminated water is provided upstream of the most upstream filter device 10.

Description

[Technical field]

[0001] The present invention relates to a tritium adsorbent that adsorbs tritium contained in tritium-contaminated water and a treatment system for tritium-contaminated water. [Background technology]

[0002] The Tohoku Pacific Ocean Earthquake that occurred on March 11, 2011 caused an accident at the Fukushima Daiichi Nuclear Power Plant, and in the decommissioning process that has been carried out since then, large amounts of cooling wastewater have been stored in numerous storage tanks. Although radioactive materials such as cesium can be removed from this wastewater, the tritiated water (tritium water) contained in it has properties similar to those of ordinary water (light water), making it difficult to separate the tritiated water from ordinary water, and in recent years, the treatment of this water as tritium-contaminated water has become a problem. For this reason, various research projects are being conducted on technologies to remove tritium from this tritium-contaminated water.

[0003] Conventional techniques for removing tritium from this type of tritium-contaminated water include, for example, a method of freezing and removing only the tritium water at subzero temperatures (Patent Document 1: International Publication WO2020 / 085046), a method of collecting tritium using an electrode membrane fixed with manganese oxide containing hydrogen ions or lithium ions having a spinel crystal structure (Patent Document 2: Japanese Patent No. 6383950), and a method of adding a predetermined amount of mineral powder such as silicon dioxide ore and nano-level carbon liquid to heated tritium-contaminated water to attenuate or eliminate tritium radioactivity (Patent Document 3: Japanese Patent No. 6713158). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. WO2020 / 085046 [Patent Document 2] Patent No. 6383950 [Patent Document 3] Patent No. 6713158 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional techniques for removing tritium have problems in that the operations are complicated and cumbersome, and the removal efficiency is poor. The present invention has been made in consideration of the above circumstances, and aims to provide a tritium adsorbent and a tritium-contaminated water treatment system that make it possible to easily remove tritium from tritium-contaminated water. [Means for solving the problem]

[0006] In order to achieve such an object, the tritium adsorbent of the present invention is a tritium adsorbent for adsorbing tritium from tritium-contaminated water, including tritiated water, The device is made of a liquid-permeable fibrous material containing fullerene and / or fullerene compounds. Tritium is an isotope of hydrogen and is often called tritiated water (THO, TDO, T 2 O) It is a nuclide that decays by emitting weak beta rays with a half-life of about 12 years.

[0007] The inventors of the present invention conducted extensive research and discovered that the fullerene structure selectively acts on tritium, leading to the completion of the present invention. Fullerene is a cluster consisting of many carbon atoms with closed shells. 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 78 Fullerene, C 84 The fullerene compound includes fullerene derivatives, for example, organic fullerenes.

[0008] As the fibrous material, fullerenes and / or fullerene compounds can be linked together in a fibrous form, for example, in the form of whisker fibers. Also, for example, fullerenes and / or fullerene compounds can be supported by impregnation, adhesion, etc., using a binder as necessary, on fibers of plastics or the like, to form a fibrous form. Also, fullerenes and / or fullerene compounds can be mixed with plastics and formed into a fibrous form. The method of forming the fibrous material is not limited to these, and any appropriate method can be adopted.

[0009] As a result, when tritium-contaminated water is brought into contact with the tritium adsorbent, the tritium in the tritiated water acts on the fullerene and / or fullerene compound and is adsorbed. This is thought to be due to the large mass of the tritiated water.

[0010] In addition, for example, it is considered that the so-called isotope exchange reaction causes the fullerene and / or fullerene compound structure to be incorporated as hydrogen (T) and to change to an organic bond type (OBT). Therefore, tritium can be easily removed from tritium-contaminated water. In this case, since the material is fibrous, the contact efficiency of the tritium-contaminated water is good, and the action can be promoted.

[0011] As a result, the tritiated water is transformed into ordinary water (light water) and the tritium contamination is removed. The tritium adsorbent that has adsorbed the tritium can be stored separately or disposed of by decomposition. The tritium-contaminated water, with the tritium removed, can be discharged into the ocean as ordinary wastewater.

[0012] In addition, the fiber material may be formed into a sheet as required. Since the fiber material is formed into a sheet, the contact efficiency of the tritium-contaminated water is improved, the action can be promoted, and handling is easy.

[0013] If necessary, the fullerene structure of the fullerene and / or fullerene compound may be 60 It is effective that it is fullerene. 60Fullerenes are truncated icosahedrons (soccer ball-shaped) made up of 60 carbon atoms, with a diameter of 7.1 angstroms. They are made up of 20 six-membered rings, 12 five-membered rings, 60 single bonds, and 30 double bonds. As mentioned above, there are many types of fullerenes, but the most common is C 60 Fullerene is superior.

[0014] In order to achieve the above object, the tritium-contaminated water treatment system of the present invention is a tritium-contaminated water treatment system that removes tritium from tritium-contaminated water containing tritium water, and is provided with a drainage path for discharging the tritium-contaminated water from a storage tank that stores the tritium-contaminated water, and is configured such that a filter device equipped with a tritium adsorbent made of a liquid-permeable fibrous material having fullerene and / or a fullerene compound is interposed in the drainage path.

[0015] As a result, when tritium-contaminated water is discharged from the storage tank into the drainage path, the tritium-contaminated water passes through the filter device. Since the filter device is provided with a tritium adsorbent, the tritium-contaminated water comes into contact with the tritium adsorbent. Through this contact, as described above, the tritium in the tritium water acts on and is adsorbed by the fullerene and / or fullerene compound, and the tritium contamination is removed. Therefore, tritium can be easily removed from the tritium-contaminated water. In this case, since the tritium adsorbent is a fibrous material, the contact efficiency of the tritium-contaminated water is good, and the action can be promoted. As a result, tritium is removed from the tritium-contaminated water, and the water can be discharged into the ocean, etc., as normal wastewater.

[0016] If necessary, an aeration tank for aerating the tritium-contaminated water is provided upstream of the filter device. Although tritium water has a large mass, it is well dispersed in the tritium-contaminated water by aeration, and the contact efficiency with the tritium adsorbent in the filter device can be improved.

[0017] In addition, if necessary, a plurality of the filter devices may be provided in series. Since the tritium-contaminated water passes through the plurality of filter devices in sequence, the opportunity for contact with the tritium adsorbent is increased, and the treatment efficiency can be improved.

[0018] Furthermore, if necessary, the tritium adsorbent is formed into a sheet shape to be configured as a filter unit, and the filter device is configured to include a case having an inlet for tritium-contaminated water at one end and an outlet at the other end, and the filter units are stacked and stored in the case from the inlet to the outlet. Since the filter units are stacked, the opportunity for contact with the tritium adsorbent increases, and the treatment efficiency can be further improved. Also, since the filter unit is in a sheet shape, it can be easily attached and detached to the case, and handling can be improved.

[0019] In this case, the fullerene structure of the fullerene and / or fullerene compound is 60 As mentioned above, there are various types of fullerenes, but C 60 Fullerene is superior. Effect of the Invention

[0020] According to the present invention, when tritium-contaminated water is brought into contact with the tritium adsorbent, the tritium in the tritium water acts on the fullerene and / or fullerene compound and is adsorbed. Therefore, tritium can be easily removed from the tritium-contaminated water. In this case, since it is a fibrous material, the contact efficiency of the tritium-contaminated water is good and the action can be promoted. As a result, the tritium water changes into ordinary water (light water) and the tritium contamination is removed. The tritium adsorbent that has adsorbed tritium can be stored separately or treated by decomposition. The tritium-contaminated water, from which tritium has been removed, can be discharged into the ocean as ordinary wastewater. [Brief description of the drawings]

[0021] [Figure 1]1 is a diagram showing a system for treating tritium-contaminated water according to an embodiment of the present invention. [Diagram 2] 1 is a perspective view showing a tritium adsorbent according to an embodiment of the present invention. FIG. [Diagram 3] 1 is an exploded perspective view showing a filter device used in a tritium-contaminated water treatment system according to an embodiment of the present invention. FIG. [Figure 4] 1 is a cross-sectional view showing a filter device used in a tritium-contaminated water treatment system according to an embodiment of the present invention. [Diagram 5] 1 is a cross-sectional view showing a treatment tank used in a treatment system for tritium-contaminated water according to an embodiment of the present invention. [Figure 6] 4 is a cross-sectional view showing another example of a treatment tank in the treatment system for tritium-contaminated water according to the embodiment of the present invention. FIG. [Figure 7] FIG. 10 is a cross-sectional view showing a filter device used in a tritium-contaminated water treatment system according to another embodiment of the present invention and its arrangement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the tritium adsorbent and the tritium-contaminated water treatment system according to the embodiment of the present invention will be described in detail with reference to the attached drawings. The tritium adsorbent according to the embodiment of the present invention is used in the tritium-contaminated water treatment system according to the embodiment of the present invention, and will be described in the treatment system.

[0023] 1 to 5, a tritium-contaminated water treatment system S according to an embodiment of the present invention is for removing tritium from tritium-contaminated water containing tritium water, and is configured with a drainage path R for draining the tritium-contaminated water from a storage tank 1 that stores the tritium-contaminated water. The storage tank 1 is, for example, about 12 m in diameter, about 12 m in height, and has a capacity of about 1000 to 1300 tons.

[0024] A filter device 10 equipped with a tritium adsorbent K for adsorbing tritium from tritium-contaminated water including tritium water is installed in the drainage path R. As shown in FIG. 2, the tritium adsorbent K is made of a liquid-permeable fibrous material having fullerene and / or a fullerene compound. Fullerene is a cluster consisting of many carbon atoms with a closed shell cavity. As a single fullerene, C 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 78 Fullerene, C 84 The fullerene compound includes fullerene derivatives, for example, organic fullerenes.

[0025] In an embodiment, the fullerene structure of the fullerene and / or fullerene compound is 60 Fullerene is selected. 60 Fullerene is a truncated icosahedron (soccer ball-shaped) structure consisting of 60 carbon atoms, with a diameter of 7.1 angstroms. It is made up of 20 six-membered rings, 12 five-membered rings, 60 single bonds, and 30 double bonds. There are various types of fullerenes, but this C 60 Fullerene is superior.

[0026] As the fibrous material, fullerenes and / or fullerene compounds can be linked together in a fibrous form, for example, in the form of whisker fibers. Also, for example, fullerenes and / or fullerene compounds can be supported by impregnation, adhesion, etc., using a binder as necessary, on fibers of plastics or the like, to form a fibrous form. Also, fullerenes and / or fullerene compounds can be mixed with plastics and formed into a fibrous form. The method of forming the fibrous material is not limited to these, and any appropriate method can be adopted.

[0027] 2 to 4, the tritium adsorbent K is formed into a sheet shape and configured as a filter unit 11. In the embodiment, for example, the length is 400 mm, the width is 400 mm, and the thickness is 5 mm.

[0028] Here is an example of making a sheet out of tritium adsorbent K using a fiber material. It is made into a nonwoven fabric mixed with fullerene using the spunbonding method, meltblowing method, flash spinning method, etc. The raw material is, for example, rice-grain-shaped plastic pellets based on polypropylene / polyethylene composite type or polylactic acid, which are made into fibers using a so-called ejector. The melted pellets are mixed with fullerene and ejected from a nozzle with many holes with a diameter of 1 mm or less. While cooling, they are made into fibers using an ejector, transported by a collector, fused with a heated roll, and embossed to make a sheet.

[0029] Furthermore, the filter device 10 is configured with a rectangular case 14 having an inlet 12 for tritium-contaminated water at one end and an outlet 13 at the other end. The case 14 is configured with a case body 15 with the outlet 13 integrally formed therein, and a lid 16 that is detachable from the case body 15 and has the inlet 12 integrally formed therein. Then, the lid 16 is opened, and the filter units 11 are stored in layers in the case body 15 from the inlet 12 to the outlet 13, and then the lid 16 is closed. In the embodiment, the size of the case 14 is formed to be, for example, 450 mm long, 450 mm wide, and 550 mm long. The tritium adsorbent K is formed from a fibrous material in a sheet shape, so that it is easy to handle when it is put in or taken out.

[0030] A plurality of filter devices 10 are provided in series. In detail, as shown in Fig. 1, a plurality of treatment tanks 20 are provided in a row in the drainage path R for sequentially storing and treating the tritium-contaminated water supplied from the storage tank 1, and each treatment tank 20 is provided with a filter device 10. As shown in Fig. 5, for example, the treatment tank 20 is a rectangular sealed tank with a side length of about 5 m, and an inlet 21 is provided at the upper part on the upstream side and an outlet 22 is provided at the lower part on the downstream side. A plurality of baffle plates 23 are provided inside the tank 20 to make the tritium-contaminated water meander up and down to flow down. The filter device 10 is detachably provided at the inlet 21 of the treatment tank 20.

[0031] As shown in FIG. 1, an aeration tank 30 is provided upstream of the most upstream treatment tank 20 (upstream of the most upstream filter device 10) to temporarily store and aerate the tritium-contaminated water supplied from the storage tank 1. The aeration tank 30 has a diameter of about 10 m and a height of about 5 m. An air injector 31 that injects air in a radial direction is provided in the center of the bottom wall, and the tritium-contaminated water in the aeration tank 30 is aerated by air from the air injector 31. The supply of tritium-contaminated water from the storage tank 1 to the aeration tank 30, the supply of tritium-contaminated water from the aeration tank 30 to the treatment tank 20, and the supply of tritium-contaminated water from the upstream treatment tank 20 to the downstream treatment tank 20 are continuously performed by gravity flow or by using an electric pump (not shown).

[0032] Therefore, when tritium is removed from tritium-contaminated water using the tritium-contaminated water treatment system S according to this embodiment, the tritium-contaminated water is supplied from the storage tank 1 to the aeration tank 30 and aeration is performed. In this case, the tritium water has a large mass, but is well dispersed in the tritium-contaminated water by aeration. Therefore, the contact efficiency with the tritium adsorbent K described later can be improved. The tritium-contaminated water can be heated to, for example, 70°C to 90°C.

[0033] Then, when the tritium-contaminated water is supplied from the aeration tank 30 to each treatment tank 20 in sequence, the tritium-contaminated water passes through the filter device 10 in each treatment tank 20. Since the filter device 10 is provided with tritium adsorbent K, the tritium-contaminated water comes into contact with the tritium adsorbent K. Then, when the tritium-contaminated water comes into contact with the tritium adsorbent K, the tritium in the tritium water acts on the fullerene and / or fullerene compound and is adsorbed. This adsorption is considered to be due to the large mass of the tritium water.

[0034] In addition, for example, it is considered that the so-called isotope exchange reaction causes the fullerene and / or fullerene compound structure to be incorporated as hydrogen (T) and to change to an organic bond type (OBT). Therefore, tritium can be easily removed from tritium-contaminated water. In this case, since the material is fibrous, the contact efficiency of the tritium-contaminated water is good, and the action can be promoted.

[0035] In this case, the filter units 11 are stored in a stacked manner from the inlet 12 to the outlet 13 inside the case body 15, so that the opportunity for the tritium water to come into contact with the tritium adsorbent K increases, and the treatment efficiency can be further improved. In addition, since a plurality of filter devices 10 are provided in series, the tritium-contaminated water passes through the plurality of filter devices 10 in sequence, so that the opportunity for contact with the tritium adsorbent K increases, and in this respect as well, the treatment efficiency can be improved.

[0036] As a result, the tritiated water is transformed into ordinary water (light water), the tritium contamination is removed, and the water can be discharged into the ocean as ordinary wastewater. The tritium adsorbent K that has adsorbed tritium can be stored separately or disposed of by decomposition, etc.

[0037] FIG. 6 shows another treatment tank 40 in a treatment system S for tritium-contaminated water according to an embodiment. A plurality of straightening plates 41 are provided inside the treatment tank 40 to form a flow path that meanders up and down. A filter device 10 is provided in every other flow path between the straightening plates 41, through which all the tritium-contaminated water flowing through the flow path passes. The filter device 10 includes a stack of sheet-like tritium adsorbent K, as described above. There may be one treatment tank 40, or a plurality of treatment tanks 40 may be provided in a row. The same actions and effects as those described above are achieved.

[0038] Fig. 7 shows a tritium-contaminated water treatment system S according to another embodiment. Unlike the above, this system does not include a treatment tank (20, 40), but includes filter devices 10 arranged in series, and tritium-contaminated water supplied from an aeration tank 30 is sequentially introduced into each filter device 10 for treatment. In the filter device 10, the sheet-shaped tritium adsorbent K is formed into a cylindrical shape and stored in a cylindrical case 50, and tritium-contaminated water is injected from an inlet 51 at the upper center of the case 50, circulated from the inside to the outside of the cylindrical tritium adsorbent K, and discharged from an outlet 52 provided on the upper side of the case 14. This system also provides the same functions and effects as those described above.

[0039] In the above embodiment, the tritium adsorbent K is formed in a sheet shape, but this is not necessarily limited to this, and it may simply be a fibrous material without being in a sheet shape, and may be modified as appropriate. In this case, for example, the tritium adsorbent made of a fibrous material can be stored in a case-shaped column having an inlet and an outlet and used as a filter device.

[0040] In addition, in the above embodiment, the aeration tank 30 is provided separately, but this is not necessarily limited to this, and an air injector for aeration may be provided in each treatment tank 20, 40, and may be modified as appropriate. In addition, the configuration of the tritium adsorbent K is not limited to the above-mentioned embodiment, and may be modified as appropriate. The present invention is not limited to the above-mentioned embodiment of the present invention, and those skilled in the art can easily make many modifications to these exemplary embodiments without substantially departing from the novel teachings and effects of the present invention, and these many modifications are included in the scope of the present invention. [Explanation of symbols]

[0041] S. Tritium-contaminated water treatment system 1 Storage tank R Drainage route K Tritium adsorbent 10 Filter device 11 Filter alone 12 Entrance 13 Exit 14 cases 15 Case body 16 Lid 20 Treatment tank 21 Inlet 22 Outlet 23 Rectifier plate 30 Aeration tank 31 Air Injector 40 Treatment tank 41 Rectifier plate 50 cases 51 Entrance 52 Exit

Claims

1. A tritium adsorbent for adsorbing tritium from tritium-contaminated water, including tritium water, A tritium adsorbent comprising a liquid-permeable fibrous material having fullerene and / or a fullerene compound.

2. 2. The tritium adsorbent according to claim 1, wherein the fiber material is formed into a sheet shape.

3. The fullerene structure of the fullerene and / or fullerene compound is ６０ 3. The tritium adsorbent according to claim 1, which is a fullerene.

4. In a tritium-contaminated water treatment system for removing tritium from tritium-contaminated water containing tritium water, A system for treating tritium-contaminated water, comprising: a drainage path for draining tritium-contaminated water from a storage tank storing the tritium-contaminated water; and a filter device having a tritium adsorbent made of a liquid-permeable fibrous material having fullerene and / or a fullerene compound, disposed in the drainage path.

5. 5. The system for treating tritium-contaminated water according to claim 4, further comprising an aeration tank for aerating the tritium-contaminated water, disposed upstream of the filter device.

6. 5. The system for treating tritium-contaminated water according to claim 4, wherein a plurality of said filter devices are provided in series.

7. 7. A system for treating tritium-contaminated water as described in any one of claims 4 to 6, characterized in that the tritium adsorbent is formed into a sheet shape and configured as a filter unit, the filter device is configured with a case having an inlet for tritium-contaminated water at one end and an outlet at the other end, and the filter units are stacked and stored in the case from the inlet to the outlet.

8. The fullerene structure of the fullerene and / or fullerene compound is ６０ 7. The system for treating tritium-contaminated water according to claim 4, wherein the tritium-contaminated water is fullerene.

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