Facility and method for reprocessing treated water

Abstract

To safely and easily store treated water by reprocessing the treated water in equipment and a method for reprocessing the treated water.SOLUTION: The Oishi incinerator includes a Oishi ash production part for burning lime stone, a treatment water solidification part for mixing and reacting quick lime produced by burning in the Oishi ash production part and treatment water to produce slaked lime and drying the slaked lime to solidify the slaked lime, and a preheat treatment part for preheating lime stone supplied to the well ash production part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a treated water retreatment facility and method. [Background technology]

[0002] For example, if an accident occurs at a nuclear power plant, contaminated water containing radioactive materials is generated. The contaminated water is purified by a treatment device, which removes radioactive materials and reduces their concentration, and then stored in a storage tank as treated water. However, the storage tank must maintain a negative pressure inside to prevent leakage of the treated water stored inside. Furthermore, if the storage tank that stores treated water deteriorates after long-term use, repairs and other work will be necessary. As a result, the storage tank's storage costs increase.

[0003] Therefore, instead of storing the treated water in a storage tank, it has been considered to store the treated water in a solid form. An example of a treated water retreatment device is described in Patent Document 1 below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-148658 Summary of the Invention [Problem to be solved by the invention]

[0005] In the device described in Patent Document 1, treated water is supplied to a water-absorbing agent to gel it. In this case, there is a problem that it is difficult to store the gel produced by gelling the treated water.

[0006] The present disclosure is intended to solve the above-mentioned problems, and aims to provide treated water retreatment equipment and a method that retreats treated water and enables it to be stored safely and easily. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the treated water reprocessing equipment disclosed herein comprises a quicklime generation unit that calcines limestone, a treated water solidification treatment unit that mixes and reacts the quicklime generated by calcination in the quicklime generation unit with treated water to generate slaked lime, and dries and solidifies the slaked lime, and a preheating treatment unit that preheats the limestone supplied to the quicklime generation unit using heat generated by the reaction in the treated water solidification treatment unit.

[0008] In addition, the method for reprocessing treated water disclosed herein includes the steps of calcining limestone, mixing and reacting the quicklime produced by the calcination with treated water to produce slaked lime, and drying the slaked lime to solidify it, and preheating the limestone before calcination using the heat generated by the reaction when the quicklime and treated water are mixed. [Effects of the Invention]

[0009] According to the treated water retreatment equipment and method disclosed herein, treated water can be retreated and stored safely and easily. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing the configuration of a treated water retreatment facility according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the raw material input section. [Figure 3] FIG. 3 is a schematic diagram showing the quicklime production section. [Figure 4] FIG. 4 is a schematic diagram showing the treated water solidification treatment unit and the storage unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0012] <Treated water reprocessing facility> FIG. 1 is a block diagram showing the configuration of a treated water retreatment facility according to this embodiment.

[0013] As shown in FIG. 1, treated water reprocessing equipment 10 reprocesses treated water generated by purifying contaminated water using a purification treatment device. For example, when an accident occurs at a nuclear power plant, contaminated water containing radioactive materials is generated. The contaminated water undergoes purification treatment using the purification treatment device, such as removing radioactive materials and reducing their concentration. However, the treated water contains at least tritium (tritium) as a radioactive material.

[0014] The treated water reprocessing facility 10 includes a raw material input section 11, a quicklime production section 12, a treated water solidification treatment section 13, a storage section 14, and a preheating treatment section 15.

[0015] The raw material input unit 11 crushes limestone (calcium carbonate / CaCO3) as a raw material and supplies it to the quicklime generation unit 12 (preheating unit 15). The quicklime generation unit 12 calcines the crushed limestone to generate quicklime (calcium oxide / CaO). The treated water solidification unit 13 mixes and reacts the quicklime generated by calcination in the quicklime generation unit 12 with treated water to generate slaked lime (calcium hydroxide / Ca(OH)2), and dries and solidifies the slaked lime. The storage unit 14 stores the treatment container in which the slaked lime solidified by the treated water solidification unit 13 is stored. The preheating unit 15 preheats the limestone to be supplied to the quicklime generation unit 12 using heat generated by the reaction in the treated water solidification unit 13.

[0016] <Raw material input section> FIG. 2 is a schematic diagram showing the raw material input section.

[0017] As shown in Fig. 2, the raw material input section 11 has a crusher 21 and a sorter 22. In addition to limestone, waste shells such as scallops and oysters are used as raw materials. However, the raw materials are not limited to these.

[0018] Limestone and waste shells are fed into a crusher 21. The crusher 21 crushes the limestone and waste shells and processes them into powder. The limestone powder crushed by the crusher 21 is supplied to a sorter 22. The sorter 22 sorts the limestone powder crushed by the crusher 21 into particles of a predetermined particle size. The sorter 22 supplies limestone powder of a predetermined particle size or smaller to the quicklime production unit 12, and returns limestone powder of a particle size exceeding the predetermined particle size to the crusher 21.

[0019] <Quicklime generating section> FIG. 3 is a schematic diagram showing the quicklime production section.

[0020] As shown in FIG. 3, the quicklime production unit 12 includes a powder transfer machine 31, a calcination furnace 32, and a carbon dioxide (CO 2 ) recovery machine 33.

[0021] The limestone powder crushed and sorted in the raw material input unit 11 is supplied to a powder transfer machine 31. The powder transfer machine 31 transfers the limestone powder and supplies it from the preheating treatment unit 15 to a calcination furnace 32. The preheating treatment unit 15 will be described later. The calcination furnace 32 produces quicklime by calcining the limestone powder at, for example, 900°C to 1100°C. When the limestone powder is calcined, quicklime and carbon dioxide are produced. The quicklime is supplied to the treated water solidification treatment unit 13. Meanwhile, the carbon dioxide is sent to a carbon dioxide capture machine 33, which captures the carbon dioxide.

[0022] <Treated Water Solidification Treatment Unit> FIG. 4 is a schematic diagram showing the treated water solidification treatment unit and the storage unit.

[0023] 4, the treated water solidification treatment unit 13 has a primary storage tank 41, a reaction tank 42, a dryer 43, and a heat exchanger 44. The treated water solidification treatment unit 13 has a building (or room) 45, which has an enclosed space that is isolated from the outside, and the primary storage tank 41, the reaction tank 42, the dryer 43, and the heat exchanger 44 are arranged in the enclosed space.

[0024] The quicklime produced in the quicklime production unit 12 is supplied to a primary storage tank 41. The primary storage tank 41 temporarily stores the quicklime. The quicklime stored in the primary storage tank 41 is supplied to the reaction tank 42 by a supply device (not shown) such as a conveyor. The treated water storage tank 46 is located outside the building 45. The treated water stored in the treated water storage tank 46 is supplied to the reaction tank 42 by a supply device (not shown) such as a pump.

[0025] The reaction tank 42 has an agitating blade 42a, and produces slaked lime by mixing and reacting the supplied quicklime with the treated water. CaO + H2O → Ca(OH)2 The slaked lime produced in the reaction tank 42 is supplied to the dryer 43. The dryer 43 separates the water content from the slaked lime. That is, the dryer 43 solidifies the slaked lime by drying it. The slaked lime separated and dried in the dryer 43 is poured into a storage container 51 and sealed. Meanwhile, the water separated in the dryer 43 is returned to the treated water storage tank 46 by a supply device (not shown) such as a pump.

[0026] When quicklime and treated water are mixed and reacted in the reaction tank 42, heat is generated. The heat exchanger 44 is provided, for example, around the reaction tank 42. The heat exchanger 44 extracts the reaction heat from the reaction tank 42 and supplies it to the preheating treatment unit 15. The preheating treatment unit 15 uses the reaction heat to preheat the quicklime powder. The heat exchanger 44 also extracts the reaction heat from the reaction tank 42 and supplies it to the dryer 43. The dryer 43 uses the reaction heat to dry the slaked lime.

[0027] <Storage Department> 4, the storage unit 14 stores storage containers 51 in which slaked lime is sealed after treatment in the treated water solidification treatment unit 13. The storage unit 14 stores a large number of storage containers 51.

[0028] <Preheating processing section> 3, the preheating unit 15 has a heat transfer unit 60. The heat transfer unit 60 has a first heat pump 61 and a second heat pump 62.

[0029] The first heat pump 61 supplies heat extracted from a radioactive waste storage container (e.g., a cask) 63 to the preheating treatment unit 15. The radioactive waste storage container 63 stores high-temperature spent nuclear fuel inside, so the outside becomes hot. For example, heat is extracted from the radioactive waste storage container 63 via a heat exchanger. The second heat pump 62 supplies heat supplied from the heat exchanger 44 (see FIG. 4) of the treated water solidification treatment unit 13 to the preheating treatment unit 15. The preheating treatment unit 15 preheats limestone powder using the heat supplied from the first heat pump 61 and the second heat pump 62.

[0030] That is, the preheating unit 15 preheats the limestone powder with the heat extracted from the radioactive waste storage container 63. The preheating unit 15 also preheats the limestone powder with the heat extracted from the reaction tank 42 by the heat exchanger 44 of the treated water solidification unit 13.

[0031] <How treated water is reprocessed> As shown in Figures 1 and 2, in the raw material input section 11, a crusher 21 crushes the input limestone and waste shells, a sorter 22 sorts the crushed limestone powder into predetermined particle sizes, and supplies the selected limestone powder having a particle size equal to or smaller than the predetermined size to a quicklime production section 12.

[0032] As shown in FIGS. 1 and 3 , in the quicklime production unit 12, the powder transfer machine 31 transfers the selected limestone powder and supplies it to the preheating unit 15. The preheating unit 15 preheats the limestone powder using heat supplied from the first heat pump 61 and the second heat pump 62. The preheating unit 15 preheats the limestone powder from room temperature to approximately 100°C, for example. The preheating unit 15 supplies the preheated limestone powder to the calcination furnace 32.

[0033] The calciner 32 produces quicklime by calcining the limestone powder preheated in the preheating treatment unit 15, for example, at 900° C. to 1100° C. The calciner 32 supplies the produced quicklime to the treated water solidification treatment unit 13.

[0034] As shown in FIGS. 1 and 4 , the primary storage tank 41 temporarily stores the quicklime generated in the quicklime generation unit 12 and supplies a predetermined amount of quicklime to the reaction tank 42. A predetermined amount of treated water stored in the treated water storage tank 46 is also supplied to the reaction tank 42. The reaction tank 42 rotates the agitator blades 42a to agitate the quicklime and treated water to properly mix them. The quicklime and treated water then react to produce slaked lime. Radioactive materials, such as tritium, contained in the treated water are then supported by the slaked lime. The dryer 43 dries the slaked lime generated in the reaction tank 42 and separates the water from the slaked lime. The slaked lime solidifies. The slaked lime solidified by the dryer 43 is placed in a storage container 51 and sealed. Because the slaked lime containing radioactive materials is difficult to dissolve in water, it can be safely stored in a storage container 51, such as a drum.

[0035] At this time, heat is generated when the quicklime reacts with the treated water in the reaction tank 42, and the heat exchanger 44 extracts the reaction heat from the reaction tank 42. The heat exchanger 44 supplies the extracted reaction heat to the preheating treatment unit 15 via the second heat pump 62. The preheating treatment unit 15 preheats the limestone powder using the reaction heat supplied from the heat exchanger 44. The heat exchanger 44 also supplies the extracted reaction heat to the dryer 43. The dryer 43 dries the slaked lime using the reaction heat.

[0036] The storage unit 14 stores a large number of storage containers 51 in which the treated water treated in the treated water solidification treatment unit 13 is filled with slaked lime.

[0037] [Effects of this embodiment] The treated water reprocessing equipment according to the first embodiment includes a quicklime generation unit 12 that calcines limestone, a treated water solidification treatment unit 13 that mixes and reacts the quicklime generated by calcination in the quicklime generation unit 12 with treated water to generate slaked lime, and dries and solidifies the slaked lime, and a preheating treatment unit 15 that preheats the limestone supplied to the quicklime generation unit 12 using heat generated by the reaction in the treated water solidification treatment unit 13.

[0038] In the treated water reprocessing facility according to the first aspect, quicklime and treated water are mixed and reacted to produce slaked lime, which is then solidified to trap radioactive materials such as tritium in the solidified slaked lime. Therefore, by reprocessing and solidifying treated water containing radioactive materials, the treated water can be safely and easily stored. Furthermore, by preheating limestone with heat generated by the reaction in the treated water solidification unit 13, the amount of heat used in the quicklime production unit 12 can be reduced, thereby reducing energy costs.

[0039] The treated water reprocessing facility according to the second embodiment is the treated water reprocessing facility according to the first embodiment, further comprising: the treated water containing at least tritium; and the treated water solidification treatment unit 13 is configured by arranging a reaction tank 42 and a dryer 43 in an enclosed space. As a result, safety can be improved by treating the treated water containing tritium in the reaction tank 42 and dryer 43 arranged in the enclosed space.

[0040] The treated water reprocessing facility according to the third embodiment is the treated water reprocessing facility according to the first or second embodiment, and further includes a treated water solidification treatment unit 13 having a heat exchanger 44 that extracts heat generated when quicklime and treated water are mixed and reacted in a reaction tank 42, and the heat extracted by the heat exchanger 44 is supplied to a preheating treatment unit 15 by a second heat pump 62. This allows the reaction heat in the reaction tank 42 to be efficiently extracted by the heat exchanger 44 and supplied to the preheating treatment unit 15 by the second heat pump 62, thereby enabling effective use of the reaction heat.

[0041] The treated water retreatment facility according to the fourth embodiment is the treated water retreatment facility according to the third embodiment, and further supplies heat extracted by the heat exchanger 44 to the dryer 43. This reduces the amount of heat used in the dryer 43, thereby enabling reductions in energy costs.

[0042] The treated water reprocessing facility according to the fifth embodiment is the treated water reprocessing facility according to any one of the first to fourth embodiments, and further supplies heat extracted from the radioactive waste storage container 63 to the preheating treatment unit 15 by the first heat pump 61. This allows the heat generated in the radioactive waste storage container 63 to be effectively utilized.

[0043] The treated water reprocessing equipment according to the sixth embodiment is the treated water reprocessing equipment according to any one of the first to fifth embodiments, and further includes a raw material input unit 11 that supplies powder obtained by pulverizing limestone to a preheating unit 15. The preheating unit 15 preheats the limestone powder supplied from the raw material input unit 11, and the quicklime generating unit 12 calcines the limestone powder preheated in the preheating unit 15. This allows the preheating unit 15 to efficiently preheat the limestone powder, and the quicklime generating unit 12 to properly calcinate the limestone powder.

[0044] The treated water reprocessing facility according to the seventh embodiment is the treated water reprocessing facility according to any one of the first to sixth embodiments, and further, the slaked lime solidified by the treated water solidification treatment unit 13 is stored and sealed in a storage container 51, and the storage container 51 storing the slaked lime is stored in the storage unit 14. This allows the slaked lime containing radioactive materials sealed in the storage container 51 to be stored safely.

[0045] The eighth aspect of the present invention relates to a method for reprocessing treated water, which includes the steps of calcining limestone, mixing the quicklime produced by calcination with treated water to generate slaked lime, and drying the slaked lime to solidify it, and preheating the limestone before calcination using heat generated by the reaction between the quicklime and treated water. This allows radioactive materials such as tritium to be trapped in the solidified slaked lime, and reprocessing and solidifying the treated water containing radioactive materials allows for safe and easy storage. Furthermore, preheating the limestone using heat generated by the reaction in the treated water solidification process reduces the amount of heat used in the quicklime generator 12, thereby reducing energy costs.

[0046] In the above-described embodiment, the treated water retreatment device and method are for retreatment of treated water obtained by purifying contaminated water containing radioactive materials generated in a nuclear power plant, but the treated water is not limited to this type of treated water. Also, although the treated water contains tritium, the treated water is not limited to this type of treated water. [Explanation of symbols]

[0047] 10 Reprocessing Facilities 11 Raw material input section 12 Quicklime production section 13 Treated water solidification treatment unit 14 Storage Department 15 Preheating processing section 21 Crusher 22 Sorting Machine 31 Powder transfer machine 32 Kiln 41 Primary storage tank 42 Reactor 43 Dryer 44 Heat exchanger 45 Building 46 Treated water storage tank 51 Storage Container 60 Heat transfer section 61 First heat pump 62 Second heat pump 63 Radioactive waste storage container

Claims

1. a quicklime generating section for burning limestone; a treated water solidification treatment unit that mixes and reacts the quicklime generated by burning in the quicklime generation unit with treated water to generate slaked lime, and dries and solidifies the slaked lime; a preheating treatment unit that preheats limestone to be supplied to the quicklime production unit using heat generated by a reaction in the treated water solidification treatment unit; Treated water reprocessing facility equipped with:

2. The treated water contains at least tritium, and the treated water solidification treatment unit is configured by arranging a reaction tank and a dryer in an enclosed space. A facility for reprocessing treated water according to claim 1.

3. The treated water solidification treatment unit has a heat exchanger that extracts heat generated when quicklime and treated water are mixed and reacted in the reaction tank, and the heat extracted by the heat exchanger is supplied to the preheating treatment unit by a heat pump. A facility for reprocessing treated water according to claim 2.

4. The heat extracted by the heat exchanger is supplied to the dryer. A facility for reprocessing treated water according to claim 3.

5. Heat extracted from a radioactive waste storage container is supplied to the preheating treatment unit by a heat pump. A facility for reprocessing treated water according to claim 1.

6. The apparatus has a raw material input section that supplies powder obtained by pulverizing limestone to the preheating processing section, the preheating processing section preheats the limestone powder supplied from the raw material input section, and the quicklime generating section calcines the limestone powder preheated in the preheating processing section. A facility for reprocessing treated water according to claim 1.

7. The slaked lime solidified by the treated water solidification treatment unit is stored in a treatment container and sealed, and the treatment container in which the slaked lime is stored is stored in a storage unit. A facility for reprocessing treated water according to claim 1.

8. Calcining the limestone; a step of mixing and reacting the quicklime produced by the burning with treated water to produce slaked lime, and drying the slaked lime to solidify it; A step of preheating limestone before calcination using heat generated by a reaction when quicklime and treated water are mixed; A method for reprocessing treated water comprising the steps of:

Images