Contaminated water treatment system and contaminated water treatment method

Abstract

To provide a contaminated water treatment system and a contaminated water treatment method capable of simultaneously removing radioactive nuclides contained in contaminated water irrespective of a dissolution form.SOLUTION: This contaminated water treatment system comprises: a contaminated water storage tank for storing contaminated water containing a plurality of radioactive nuclides; one or more suction towers that are connected to the contaminated water storage tank so as to remove the radioactive nuclides from the contaminated water; and a treated water storage tank that is connected to the suction towers so as to store treated water resulting from removing the radioactive nuclides from the contaminated water. Each suction tower includes a precoat suction material capable of removing the radioactive nuclides from the contaminated water. The precoat suction material contains a porous material capable of sucking the radioactive nuclides which take colloidal forms from the contaminated water and a power suction material capable of sucking the radioactive nuclides which take ion forms from the contaminated water.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a contaminated water treatment system and a contaminated water treatment method. [Background technology]

[0002] Contaminated water discharged from nuclear power plants and facilities that handle radioactive materials contains alpha-, beta-, and gamma-ray-emitting nuclides (hereinafter referred to as alpha, beta, and gamma nuclides) derived from nuclear fission and nuclear fuel. Various contaminated water treatment facilities have been proposed to purify these radioactive nuclides to the legally mandated concentration levels.

[0003] However, because these radionuclides exist in contaminated water in different dissolved forms, such as ionic and colloidal forms, it was necessary to develop contaminated water treatment equipment that combined filters, adsorption towers, etc. to deal with each of these forms. As a result, previous contaminated water treatment equipment had the problem of being too complex and large-scale.

[0004] In addition, conventional contaminated water treatment facilities have mainly used organic adsorbents to remove these radionuclides from contaminated water. However, these organic adsorbents have had to be replaced periodically due to a decrease in functionality caused by radiation degradation and limitations on the amount of adsorption, which can cause problems such as worker exposure and an increase in secondary waste. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2023-118283 [Patent Document 2] Patent Publication No. 2020-76650 [Patent Document 3] Patent Publication No. 2016-90556 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention addresses these circumstances, and the problem that the present invention aims to solve is to provide a contaminated water treatment system and a contaminated water treatment method that can simultaneously remove radioactive nuclides contained in contaminated water regardless of their dissolved form. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the contaminated water treatment system of this embodiment is a contaminated water treatment system that removes multiple types of radionuclides from contaminated water containing the multiple types of radionuclides, and comprises: a contaminated water storage tank for storing the contaminated water containing the multiple types of radionuclides; one or more adsorption towers connected to the contaminated water storage tank for removing the multiple types of radionuclides from the contaminated water; and a treated water storage tank connected to the adsorption tower for storing treated water from the contaminated water from which the multiple types of radionuclides have been removed, wherein the adsorption tower has a pre-coated adsorbent capable of removing the multiple types of radionuclides from the contaminated water, and the pre-coated adsorbent comprises a porous material capable of adsorbing the multiple types of radionuclides in colloidal form from the contaminated water, and a powder adsorbent capable of adsorbing the multiple types of radionuclides in ionic form from the contaminated water.

[0008] and a step of measuring a radiation dose of at least one of the treated water and the adsorbed powder adsorbent, and determining whether the radiation dose of at least one of the treated water and the adsorbed powder adsorbent is less than a predetermined value. [Effects of the Invention]

[0009] The embodiments of the present invention have been made to solve the above-mentioned problems, and thereby make it possible to simultaneously remove radionuclides contained in contaminated water regardless of their dissolved form using a single facility. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a contaminated water treatment system 1 according to a first embodiment. [Figure 2] FIG. 4 is an explanatory diagram showing the process of forming a precoated adsorbent. [Figure 3] 1 is a flowchart showing a contaminated water treatment method 100 according to a first embodiment. [Figure 4] FIG. 10 is a schematic configuration diagram of a contaminated water treatment system 50 according to a second embodiment. [Figure 5] 10 is a flowchart showing a contaminated water treatment method 200 according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] A contaminated water treatment system and a contaminated water treatment method according to an embodiment of the present invention will be described in detail below with reference to the drawings. Note that the embodiments shown below are illustrative of embodiments of the present invention and are not intended to limit the scope of the invention. Furthermore, in the drawings referred to in the embodiments, identical parts or parts having similar functions are given the same or similar reference numerals, and their description may be omitted. Furthermore, the dimensional ratios of the drawings may differ from the actual ratios, and some components may be omitted from the drawings.

[0012] (First embodiment) A contaminated water treatment system 1 according to the first embodiment will be described with reference to Figure 1. The contaminated water to be treated by the contaminated water treatment system 1 according to the first embodiment is contaminated water containing radioactive nuclides such as alpha nuclides, beta nuclides, and gamma nuclides, which is discharged from, for example, a nuclear power plant or a facility that handles radioactive materials.

[0013] FIG. 1 is a schematic diagram of a contaminated water treatment system 1 according to a first embodiment. The contaminated water treatment system 1 is a facility for removing multiple radionuclides from contaminated water to produce treated water in which the radiation dose has been reduced to a predetermined value, for example, the concentration value required by law. The system includes a contaminated water storage tank 2, a water quality analyzer 3, an adsorption tower 4, a powder adsorbent storage tank 5, a treated water storage tank 6, a treated water radiation measuring instrument 7, an adsorbed powder adsorbent radiation measuring instrument 8, a powder adsorbent recovery tank 9, and a control device C. Note that in the drawings referenced in the following description, the open / closed states of various valves are represented by black-colored valves as closed and white-colored valves as open. In particular, FIG. 1 illustrates an example in which all valves are open (white-colored), but the open / closed states of these valves are controlled by the control device C.

[0014] The contaminated water storage tank 2 is a device for storing contaminated water containing radioactive nuclides. The contaminated water storage tank 2 is connected to one end of a pipe 10, and contaminated water discharged from a nuclear power plant, a facility that handles radioactive materials, etc. is transported through this pipe 10. The contaminated water storage tank 2 is connected to one end of a pipe 11, and the contaminated water is transported through this pipe 11 to the adsorption tower 4. The pipe 11 is provided with a valve 12 for opening and closing the flow path and a pump 13 for transporting the contaminated water. The contaminated water storage tank 2 is also connected to one end of a pipe 14, and the contaminated water is transported through this pipe 14 to the water quality analysis device 3. The pipe 14 is provided with a valve 15 for opening and closing the flow path.

[0015] The water quality analyzer 3 is a device for periodically analyzing the quality of the contaminated water stored in the contaminated water storage tank 2. Based on the analysis results of the quality of the contaminated water, the water quality analyzer 3 selects, for example, the type of precoated adsorbent to be used in contaminated water treatment to remove radionuclides from the contaminated water in the adsorption tower 4. The type of precoated adsorbent here refers to a combination of a porous material and a powder adsorbent.

[0016] The porous material referred to here is a substance capable of adsorbing colloidal radionuclides from contaminated water, and is preferably an inorganic substance that is relatively resistant to radiation degradation. Examples of porous materials include activated carbon, zeolite, and silica. However, it is not intended that the porous material must not be an organic substance.

[0017] The powder adsorbent referred to here is a substance capable of adsorbing ionic radionuclides from contaminated water, capable of being precoated onto a porous material, and preferably an inorganic substance that is relatively resistant to radiation degradation. Examples of powder adsorbents include iron-based adsorbents including magnetite and ferrite, zirconium-based adsorbents, zeolite-based adsorbents, and titanium-based adsorbents. However, it is not intended that the powder adsorbent must not be an organic substance.

[0018] The precoated adsorbent here refers to a substance that can simultaneously remove both ionic and colloidal radionuclides from contaminated water, regardless of the dissolved form they are in. That is, even in contaminated water containing a mixture of ionic and colloidal radionuclides, the porous portion of the precoated adsorbent adsorbs the colloidal radionuclides, and the powdered portion of the precoated adsorbent adsorbs the ionic radionuclides.

[0019] The adsorption tower 4 is a device for removing radionuclides from contaminated water containing radionuclides. The adsorption tower 4 is filled with a porous material required to form a precoated adsorbent. The adsorption tower 4 is connected to the other end of a pipe 11, through which contaminated water is sent from the contaminated water storage tank 2. The adsorption tower 4 is connected to one end of a pipe 16, through which the treated water, which is contaminated water from which radionuclides have been removed, is sent to the treated water storage tank 6, which will be described later. The pipe 16 is provided with valves 17 and 18 for opening and closing the flow path and a pump 19 for sending the treated water.

[0020] The powder adsorbent storage tank 5 is a device for storing the powder adsorbent required to form the precoated adsorbent. The powder adsorbent storage tank 5 is connected to one end of a pipe 20, and the powder adsorbent is introduced to the adsorption tower 4 via this pipe 20. The pipe 20 is provided with a valve 21 for opening and closing the flow path and a pump 22 for introducing the powder adsorbent. The powder adsorbent storage tank 5 is connected to one end of a pipe 23, and the powder adsorbent is recovered from the adsorption tower 4 via this pipe 23.

[0021] Here, the process of forming the precoated adsorbent in the adsorption tower 4 will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram showing the process of forming the precoated adsorbent.

[0022] First, the porous material 24 is packed into the adsorption tower 4 (the state shown in FIG. 2(a)).

[0023] Next, when the control device C opens the valve 21, the powder adsorbent 25 is introduced from the powder adsorbent storage tank 5 to the adsorption tower 4 via the pipe 20 and the pump 22. Once introduced into the adsorption tower 4, the powder adsorbent 25 is stirred together with the porous material 24 within the adsorption tower 4 (the state shown in FIG. 2(b)).

[0024] Finally, due to the physical interaction between the porous material 24 and the powder adsorbent 25 caused by the stirring, the powder adsorbent 25 is pre-coated onto the porous material 24, forming a pre-coated adsorbent 26 (the state shown in FIG. 2(c)).

[0025] The precoated adsorbent 26 may be formed using a porous material 24 and a powder adsorbent 25 having different specific gravities. This may allow the adsorption tower 4 to be separated into the porous material 24 and the powder adsorbent 25 by a backwashing operation. The separated powder adsorbent 25 may then be recovered from the adsorption tower 4 to the powder adsorbent storage tank 5 via the pipe 23.

[0026] Furthermore, in the present embodiment, a case where one adsorption tower 4 and one powder adsorbent storage tank 5 are provided has been described as an example, but the present invention is not limited to this. For example, a plurality of powder adsorbent storage tanks 5 may be provided for each type. This may enable the powder adsorbent 25 to be pre-coated on the porous material 24 in the adsorption tower 4 to be selected based on the analysis results of the quality of the contaminated water by the water quality analyzer 3.

[0027] Alternatively, for example, a plurality of adsorption towers 4 may be provided for each type. This may allow the porous material 24 to be pre-coated with the powder adsorbent 25 to be selected based on the analysis results of the water quality of the contaminated water by the water quality analyzer 3. Furthermore, for example, a plurality of adsorption towers 4 may be provided in series, and the water flow order may be changed by switching valves. This may allow the water flow order, for example, from the first tower, second tower, and third tower to be changed to the second tower, third tower, and first tower as the old porous material 24 in the first tower is replaced with a new porous material 24.

[0028] Furthermore, for example, a plurality of adsorption towers 4 and powder adsorbent storage tanks 5 may be provided for each type. This allows the porous material 24 and the powder adsorbent 25 to be pre-coated on the porous material 24 to be freely combined based on the analysis results of the water quality of the contaminated water by the water quality analyzer 3.

[0029] The treated water storage tank 6 is a device for storing treated water obtained by removing radionuclides from contaminated water in the adsorption tower 4. The treated water storage tank 6 is connected to the other end of piping 16, and the treated water is delivered from the adsorption tower 4 via this piping 16. The treated water storage tank 6 is connected to one end of piping 27, and the treated water is delivered to downstream equipment via this piping 27. The piping 27 is provided with a valve 28 for opening and closing the flow path and a pump 29 for delivering the treated water. The treated water storage tank 6 is also connected to one end of piping 30, and the treated water is delivered to the treated water radiation measuring instrument 7 via this piping 30. The piping 30 is provided with a valve 31 for opening and closing the flow path.

[0030] The treated water storage tank 6 has the function of separating and recovering the adsorbed powder adsorbent, which becomes powder adsorbent that has adsorbed radionuclides, from the treated water. The powder adsorbent adsorbs ionic radionuclides from the contaminated water as the contaminated water passes through the precoated adsorbent in the adsorption tower 4. This adsorbed powder adsorbent, which becomes powder adsorbent that has adsorbed ionic radionuclides, peels off from the porous material and is included in the treated water, leading to the treated water storage tank 6 along with the treated water. Therefore, the treated water storage tank 6 must separate and recover the adsorbed powder adsorbent contained in the treated water. Methods for separating the adsorbed powder adsorbent in the treated water storage tank 6 include, for example, gravity settling, separation using a strainer or filter, centrifugation using a cyclone separator, and separation using an electromagnetic coil attached to the treated water storage tank 6. The treated water storage tank 6 is connected to one end of a pipe 32, and the adsorbed powder adsorbent separated in the treated water storage tank 6 is guided from the treated water storage tank 6 to an adsorbed powder adsorbent radiation counter 8 via the pipe 32. The pipe 32 is provided with a valve 33 for opening and closing the flow path.

[0031] The treated water radiation measuring instrument 7 is a device for periodically measuring the radiation dose of treated water. The treated water radiation measuring instrument 7 determines whether the radiation dose of treated water stored in the treated water storage tank 6 is below a predetermined value in order to prevent the outflow of highly concentrated radioactive materials to downstream equipment. The predetermined value here refers to the concentration value notified regarding radiation dose safety. If the treated water radiation measuring instrument 7 determines that the radiation dose of the treated water is below the predetermined value, it sends the treated water to downstream equipment. Specifically, the treated water radiation measuring instrument 7 is connected to one end of a pipe 34, and sends the treated water to the downstream equipment via this pipe 34. The pipe 34 is provided with a valve 35 for opening and closing the flow path.

[0032] On the other hand, when the treated-water radiation measuring instrument 7 determines that the radiation dose of the treated water is not less than the predetermined value, it sends the treated water to the adsorption tower 4. Specifically, the treated-water radiation measuring instrument 7 is connected to one end of a pipe 36, and sends the treated water to the pipe 11 via this pipe 36. This pipe 36 is provided with a valve 37 for opening and closing the flow path and a pump 38 for sending the treated water.

[0033] The adsorbed powder adsorbent radiation counter 8 is a device for measuring the radiation dose of the adsorbed powder adsorbent. To prevent the increase of secondary waste, the adsorbed powder adsorbent radiation counter 8 determines whether the radiation dose of the adsorbed powder adsorbent separated and recovered in the treated water storage tank 6 is below a predetermined value. The predetermined value here refers to the concentration value notified regarding radiation dose safety. If the adsorbed powder adsorbent radiation counter 8 determines that the radiation dose of the adsorbed powder adsorbent is below the predetermined value, it guides the adsorbed powder adsorbent to the powder adsorbent storage tank 5. Specifically, the adsorbed powder adsorbent radiation counter 8 is connected to one end of a pipe 39, and the adsorbed powder adsorbent is guided to the powder adsorbent storage tank 5 via this pipe 39. A valve 40 for opening and closing the flow path is provided in the pipe 39.

[0034] On the other hand, when adsorbed powder adsorbent radiation measuring instrument 8 determines that the radiation dose of the adsorbed powder adsorbent is not less than the predetermined value, it guides the adsorbed powder adsorbent to powder adsorbent recovery tank 9. Specifically, adsorbed powder adsorbent radiation measuring instrument 8 is connected to one end of piping 41, and guides the adsorbed powder adsorbent to powder adsorbent recovery tank 9 via this piping 41. Piping 41 is provided with a valve 42 for opening and closing the flow path.

[0035] Powder adsorbent recovery tank 9 is a device for recovering and storing adsorbed powder adsorbent whose radiation dose is not less than a predetermined value. Powder adsorbent recovery tank 9 is connected to the other end of pipe 41, and adsorbed powder adsorbent is introduced from adsorbed powder adsorbent radiation measuring instrument 8 via this pipe 41. This powder adsorbent recovery tank 9 is preferably a container that combines a dehydration function and a waste storage function. Note that, although the present embodiment illustrates a case in which powder adsorbent recovery tank 9 is connected only to adsorbed powder adsorbent radiation measuring instrument 8, it may also be connected to treated water storage tank 6.

[0036] The control device C includes one or more processors (not shown) and a memory (not shown). The control device C controls the various devices, valves, and pumps described above by having the one or more processors (not shown) execute software programs and / or instruction sets stored in the memory (not shown).

[0037] Next, a contaminated water treatment method 100 according to the first embodiment will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the contaminated water treatment method 100 according to the first embodiment. The contaminated water treatment method 100 is carried out by a control device C controlling various devices, various valves, and various pumps.

[0038] First, the water quality analyzer 3 analyzes the quality of the contaminated water (step S101). Specifically, the control device C opens the valve 15, and the contaminated water stored in the contaminated water storage tank 2 is sent to the water quality analyzer 3. Then, the water quality analyzer 3 analyzes the quality of the contaminated water.

[0039] Next, the water quality analyzer 3 selects a porous material and a powder adsorbent for removing radionuclides from the contaminated water (step S102). Specifically, when a plurality of adsorption towers 4 and / or powder adsorbent storage tanks 5 are provided for each type, the water quality analyzer 3 selects a combination of a porous material and a powder adsorbent suitable for removing radionuclides from the contaminated water based on the analysis results of the quality of the contaminated water.

[0040] Next, the adsorption tower 4 forms a precoated adsorbent from the porous material and powder adsorbent selected by the water quality analysis device 3 (step S103). Specifically, the control device C opens the valve 21, and the powder adsorbent selected by the water quality analysis device 3 is introduced into the adsorption tower 4 filled with the porous material selected by the water quality analysis device 3. The adsorption tower 4 then agitates the porous material and powder adsorbent, thereby precoating the powder adsorbent onto the porous material and forming a precoated adsorbent.

[0041] Next, the precoated adsorbent removes radionuclides from the contaminated water (step S104). Specifically, the control device C opens the valve 12, and the contaminated water stored in the contaminated water storage tank 2 is sent to the adsorption tower 4. Then, the precoated adsorbent in the adsorption tower 4 removes colloidal and ionic radionuclides from the contaminated water sent to the adsorption tower 4.

[0042] Next, the treated water storage tank 6 separates the adsorbed powder adsorbent, which is the powder adsorbent that has adsorbed radionuclides, from the treated water stored in the treated water storage tank 6 (step S105). Specifically, the control device C opens the valve 17, and the treated water, which is contaminated water from which radionuclides have been removed, is delivered from the adsorption tower 4 to the treated water storage tank 6. At this time, the treated water is delivered together with the adsorbed powder adsorbent, which is the powder adsorbent that has adsorbed radionuclides in ion form. The treated water storage tank 6 then separates the adsorbed powder adsorbent from the treated water using a predetermined separation method. The predetermined separation method here refers to, for example, gravity settling separation, separation using a strainer or filter, centrifugal separation using a cyclone separator, separation using an electromagnetic coil attached to the treated water storage tank 6, etc.

[0043] Thereafter, the radiation doses of the treated water stored in the treated-water storage tank 6 and the adsorbed powder adsorbent are measured (step S106). Specifically, if the measurement target is treated water (YES in step S107), the control device C opens valve 31, and the treated water stored in the treated-water storage tank 6 is sent to the treated-water radiation measuring device 7. The treated-water radiation measuring device 7 then measures the radiation dose of the treated water and determines whether the radiation dose of the treated water is below a predetermined value. The predetermined value here refers to the concentration value notified regarding radiation dose safety. If the radiation dose of the treated water is below the predetermined value (YES in step S108), the treated-water radiation measuring device 7 determines that radionuclides have been sufficiently removed from the contaminated water, and the control device C opens valve 28 or valve 35. Then, the treated water is sent from the treated water storage tank 6 or the treated water radiation measuring instrument 7 to downstream equipment, and the contaminated water treatment is completed (step S109). On the other hand, if the radiation dose of the treated water is not less than the predetermined value (NO in step S108), the treated water radiation measuring instrument 7 determines that radioactive nuclides have not been sufficiently removed from the contaminated water, and the control device C opens the valve 37. Then, the treated water is sent from the treated water radiation measuring instrument 7 to the adsorption tower 4, and the contaminated water treatment using the precoated adsorbent is repeated again (return to step S104).

[0044] On the other hand, if the measurement target is not treated water (NO in step S107), the control device C opens valve 33, and the adsorbed powder adsorbent stored in the treated water storage tank 6 is introduced to adsorbed powder adsorbent radiation measuring device 8. Then, adsorbed powder adsorbent radiation measuring device 8 measures the radiation dose of the adsorbed powder adsorbent and determines whether the radiation dose of the adsorbed powder adsorbent is below a predetermined value. The predetermined value here refers to the concentration value notified regarding radiation dose safety. If the radiation dose of the adsorbed powder adsorbent is below the predetermined value (YES in step S110), the adsorbed powder adsorbent radiation measuring device 8 determines that the adsorbed powder adsorbent can be reused, and the control device C opens valve 40. Then, the adsorbed powder adsorbent is introduced from adsorbed powder adsorbent radiation measuring device 8 to the powder adsorbent storage tank 5, and the powder adsorbent storage tank 5 reuses the adsorbed powder adsorbent (return to step 103). On the other hand, if the radiation dose of the adsorbed powder adsorbent is not less than the predetermined value (NO in step S110), adsorbed powder adsorbent radiation measuring instrument 8 determines that the adsorbed powder adsorbent cannot be reused, and control device C opens valve 42. Then, the adsorbed powder adsorbent is guided from adsorbed powder adsorbent radiation measuring instrument 8 to powder adsorbent recovery tank 9, which recovers and stores the adsorbed powder adsorbent (step S111).

[0045] As described above, according to the contaminated water treatment system 1 and contaminated water treatment method 100 of this embodiment, the precoated adsorbent, which is a porous material precoated with a powder adsorbent, simultaneously removes ionic and colloidal radionuclides from contaminated water, regardless of their dissolved form. Conventionally, in order to remove ionic and colloidal radionuclides, it was necessary to combine corresponding filters, adsorption towers, etc., which resulted in complex and large-scale equipment. In contrast, in this embodiment, the use of a precoated adsorbent makes it possible to simultaneously remove ionic and colloidal radionuclides from contaminated water using a single facility (adsorption tower 4), thereby simplifying and downsizing the facility.

[0046] Furthermore, according to the contaminated water treatment system 1 and contaminated water treatment method 100 of this embodiment, the adsorbed powder adsorbent is separated and recovered from the treated water, and is reused for contaminated water treatment if the radiation dose of the adsorbed powder adsorbent is below a predetermined value. Conventionally, organic adsorbents used in contaminated water treatment facilities required periodic replacement due to functional decline caused by radiation degradation and limitations on adsorption capacity, resulting in an increase in secondary waste associated with such periodic replacement. In contrast, this embodiment uses a powder adsorbent that is an inorganic substance that is relatively resistant to radioactive degradation, and allows the adsorbed powder adsorbent to be reused if the radiation dose is below a predetermined value, thereby reducing the generation of secondary waste.

[0047] Furthermore, according to the contaminated water treatment system 1 and contaminated water treatment method 100 of this embodiment, inorganic porous materials and powder adsorbents remove radionuclides from contaminated water. Conventionally, organic adsorbents used in contaminated water treatment facilities required periodic replacement due to functional decline caused by radiation degradation and limitations on adsorption capacity, posing a risk of worker exposure during periodic replacement. In contrast, this embodiment uses inorganic porous materials and powder adsorbents that are relatively resistant to radiation degradation, thereby extending the replacement cycle and reducing the risk of worker exposure during periodic replacement.

[0048] Furthermore, according to the contaminated water treatment system 1 and the contaminated water treatment method 100 of this embodiment, the porous material and / or powder adsorbent is selected in accordance with the quality of the contaminated water. This allows the precoated adsorbent to be formed with an optimal combination suited to the quality of the contaminated water, thereby ensuring the performance of removing radionuclides from the contaminated water.

[0049] In this embodiment, the adsorption tower 4 and powder adsorbent storage tank 5 are provided between the contaminated water storage tank 2 and the treated water storage tank 6, and radioactive nuclides such as α-, β-, and γ-nuclides contained in the contaminated water are removed by the pre-coated adsorbent in the adsorption tower 4. However, the present invention is not limited to this. For example, the adsorption tower 4 and powder adsorbent storage tank 5 between the contaminated water storage tank 2 and the treated water storage tank 6 may be configured to remove α-nuclides contained in the contaminated water, and the adsorption tower, powder adsorbent storage tank, and treated water storage tank additionally provided downstream of the treated water storage tank 6 may be configured to remove β- and γ-nuclides contained in the contaminated water.

[0050] (Second embodiment) A contaminated water treatment system 50 according to the second embodiment will be described using Figure 4. Hereinafter, only the parts that differ from the first embodiment will be described, and the other parts will be assigned the same reference numerals as those in the first embodiment, and descriptions of their configurations will be omitted.

[0051] 4 is a schematic diagram of a contaminated water treatment system 50 according to the second embodiment. The contaminated water treatment system 50 includes a water quality analyzer 3, an adsorption tower 4, a powder adsorbent storage tank 5, a treated water storage tank 6, a treated water radiation measuring instrument 7, an adsorbed powder adsorbent radiation measuring instrument 8, a powder adsorbent recovery tank 9, a pretreatment device 43, and a control device C. That is, the contaminated water treatment system 50 according to the second embodiment differs from the contaminated water treatment system 1 according to the first embodiment in that the contaminated water storage tank 2 is the pretreatment device 43. Note that, although FIG. 4 illustrates an example in which all valves are in the open state (white-out state), the open / closed states of these valves are controlled by the control device C.

[0052] The pretreatment device 43 is a device for storing contaminated water containing radionuclides. The pretreatment device 43 also performs pretreatment on the stored contaminated water. That is, the pretreatment device 43 is a device that, in addition to the functions of the contaminated water storage tank 2, also has the function of performing pretreatment of the contaminated water. Pretreatment here includes rough removal of radionuclides, removal of poorly adsorbed substances such as cobalt, manganese, or nickel, removal of adsorption inhibitors derived from seawater components, removal of adsorption tower blocking substances such as sand and iron rust components, stabilization of chemical form, pH adjustment, precipitation separation, filtration, centrifugation, membrane separation, desalination, and the like. This pretreatment may be performed based on the results of an analysis of the water quality of the contaminated water by the water quality analyzer 3. In this embodiment, the pretreatment device 43 is described using a chemical solution.

[0053] The pretreatment device 43 includes a chemical tank 44 and an agitator 45 .

[0054] The chemical tank 44 is a device for storing a chemical solution for pretreating contaminated water. Examples of chemical solutions include pH adjusters and coprecipitants (ferric chloride, sodium hydroxide, calcium hydroxide, calcium chloride, etc.). For example, a pH adjuster is used to adjust the chemical form of radionuclides to be soluble or insoluble. Furthermore, a coprecipitant is used to remove radionuclides, poorly adsorbed substances, adsorption inhibitors, or adsorption tower blocking substances by coprecipitation. The chemical tank 44 is connected to one end of a pipe 46 and delivers the chemical solution to the pretreatment device 43 via the pipe 46. The pipe 46 is provided with a valve 47 for opening and closing the flow path. While the present embodiment illustrates a case in which one chemical tank 44 is provided, multiple chemical tanks of different types may be provided.

[0055] The agitator 45 is a device for agitating the contaminated water. The agitator 45 is used to make the particle content gradient in the contaminated water uniform and to mix the contaminated water with the chemical solution added from the chemical tank 44.

[0056] Next, a contaminated water treatment method 200 according to a second embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing the contaminated water treatment method 200 according to the second embodiment. The contaminated water treatment method 200 is executed by a control device C controlling various devices, various valves, and various pumps.

[0057] The contaminated water treatment method 200 according to the second embodiment differs from the contaminated water treatment method 100 according to the first embodiment in that the pretreatment device 43 further includes a step (step S201) of performing pretreatment of the contaminated water stored in the pretreatment device 43. This step 201 is performed between the above-mentioned steps S101 and S102. Specifically, the control device C opens the valve 47, and the pretreatment device 43 adds a chemical solution from the chemical solution tank 44 to the contaminated water in the pretreatment device 43 based on the analysis result of the water quality of the contaminated water by the water quality analysis device 3 in step S101. For example, if the analysis result by the water quality analysis device 3 shows that it is necessary to adjust the chemical solution to the properties of the porous material and powder adsorbent used, a pH adjuster is added from the chemical solution tank 44 to the contaminated water in the pretreatment device 43. Furthermore, for example, if the analysis by the water quality analysis device 3 indicates that it is necessary to remove poorly adsorbable substances and adsorption inhibitors from the porous material and powder adsorbent used, or if it is necessary to remove adsorption tower blocking substances that reduce the performance of the adsorption tower 4, a coprecipitant is added from the chemical tank 44 to the contaminated water in the pretreatment device 43.

[0058] As described above, the contaminated water treatment system 50 and the contaminated water treatment method 200 of this embodiment have the same functions and effects as the first embodiment, and the pretreatment device 43 performs pretreatment of the contaminated water before performing contaminated water treatment using the precoated adsorbent. This makes it possible to adjust the quality of the contaminated water in advance to a level suitable for the precoated adsorbent to remove radionuclides, thereby ensuring the performance of removing radionuclides from the contaminated water.

[0059] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0060] 1...contaminated water treatment system, 2...contaminated water storage tank, 3...water quality analysis device, 4...adsorption tower, 5...powder adsorbent storage tank, 6...treated water storage tank, 7...treated water radiation measuring device, 8...adsorbed powder adsorbent radiation measuring device, 9...powder adsorbent recovery tank, 43...pretreatment device, 44...chemical tank, 45...agitator, 50...contaminated water treatment system, 100...contaminated water treatment method, 200...contaminated water treatment method.

Claims

1. A contaminated water treatment system for removing multiple types of radionuclides from contaminated water containing the multiple types of radionuclides, a contaminated water storage tank for storing the contaminated water containing the plurality of types of radionuclides; one or more adsorption towers connected to the contaminated water storage tank for removing the plurality of radionuclides from the contaminated water; a treated water storage tank connected to the adsorption tower for storing treated water obtained by removing the plurality of radionuclides from the contaminated water; Equipped with the adsorption tower has a precoated adsorbent capable of removing the plurality of types of radionuclides from the contaminated water, a powder adsorbent capable of adsorbing the plurality of radioactive nuclides that become colloidal from the contaminated water; and a powder adsorbent capable of adsorbing the plurality of radioactive nuclides that become ionic from the contaminated water.

2. further comprising one or more powder adsorbent storage tanks connected to the adsorption tower for storing the powder adsorbent; 2. The contaminated water treatment system according to claim 1, wherein the precoated adsorbent comprises the porous material filled in the adsorption tower and the powder adsorbent sent from the powder adsorbent storage tank to the adsorption tower.

3. 2. The contaminated water treatment system according to claim 1, wherein the porous material and the powder adsorbent are inorganic substances.

4. Further provided is a water quality analyzer connected to the contaminated water storage tank for analyzing the quality of the contaminated water; 2. The contaminated water treatment system according to claim 1, wherein the water quality analyzer is capable of selecting the type of the precoated adsorbent based on the analysis result of the water quality of the contaminated water.

5. further comprising a treated water radiation measuring device connected to the treated water storage tank for measuring the radiation dose of the treated water; 2. The contaminated water treatment system according to claim 1, wherein the treated water radiation measuring device determines whether the radiation dose of the treated water is less than a predetermined value.

6. further comprising an adsorbed powder adsorbent radiation measuring device connected to the treated water storage tank for measuring the radiation dose of the adsorbed powder adsorbent that has adsorbed the plurality of radioactive nuclides that have been converted into ions from the contaminated water; 2. The contaminated water treatment system according to claim 1, wherein the adsorbed powder adsorbent radiation measuring device determines whether the radiation dose of the adsorbed powder adsorbent is less than a predetermined value.

7. 7. The contaminated water treatment system according to claim 6, further comprising a powder adsorbent recovery tank connected to the adsorbed powder adsorbent radiation measuring instrument for recovering and storing the adsorbed powder adsorbent.

8. 8. The contaminated water treatment system according to claim 1, wherein the contaminated water storage tank is a pretreatment device capable of performing pretreatment of contaminated water.

9. 9. The contaminated water treatment system according to claim 8, wherein the pretreatment is any one of rough removal of radionuclides, removal of poorly adsorbed substances, removal of adsorption inhibitors derived from seawater components, removal of substances blocking the adsorption tower such as sand and iron rust components, stabilization of chemical form, pH adjustment, precipitation separation, filtration, centrifugation, membrane separation, and desalination.

10. Further, a water quality analyzer is connected to the pretreatment device and configured to analyze the quality of the contaminated water.

9. The contaminated water treatment system according to claim 8, wherein the pretreatment device performs the pretreatment of the contaminated water based on the analysis result of the water quality of the contaminated water by the water quality analyzer.

11. A contaminated water treatment method for removing multiple types of radionuclides from contaminated water containing the multiple types of radionuclides, comprising: analyzing the quality of the contaminated water; selecting a porous material and a powder adsorbent material for removing the plurality of radionuclides from the contaminated water based on the results of the analysis; forming a precoated adsorbent material from the porous material and the powder adsorbent material; removing the plurality of radionuclides from the contaminated water using the precoated adsorbent; a step of separating an adsorbed powder adsorbent, which becomes the powder adsorbent having adsorbed the plurality of radionuclides, from treated water, which is obtained by removing the plurality of radionuclides from the contaminated water; measuring the radiation dose of at least one of the treated water and the adsorbed powder adsorbent, and determining whether the radiation dose of at least one of the treated water and the adsorbed powder adsorbent is less than a predetermined value; A contaminated water treatment method comprising:

12. If the radiation dose of the treated water is less than a predetermined value, the contaminated water treatment is completed; If the radiation dose of the treated water is not less than a predetermined value, repeating the contaminated water treatment using the precoated adsorbent again; The method for treating contaminated water according to claim 11, further comprising:

13. If the radiation dose of the adsorbed powder adsorbent is less than a predetermined value, reusing the adsorbed powder adsorbent; If the radiation dose of the adsorbed powder adsorbent is not less than a predetermined value, recovering and storing the adsorbed powder adsorbent; The method for treating contaminated water according to claim 11, further comprising:

14. 14. The contaminated water treatment method according to claim 11, further comprising the step of performing pretreatment of the contaminated water based on the results of the analysis.

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