Double-shell tank, treatment system, and method for using double-shell tank

Abstract

To provide a double shell tank or the like in consideration of a function when damaged.SOLUTION: An aqueous solution and pure water are stored in an inner tank and an outer tank of a double shell tank, respectively, and the pressure of the pure water is higher than that of the aqueous solution. The processing system includes a control unit that controls the pressure of the pure water in the double-shell tank in which the aqueous solution is stored in the inner tank and the pure water is stored in the outer tank, and the control unit controls the pressure of the pure water so that the pressure of the pure water is higher than the pressure of the aqueous solution. The processing system may include a detector that detects damage to the inner tank or the outer tank based on the pressure of the aqueous solution or the pure water.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to double-shelled tanks, treatment systems and methods of using double-shelled tanks. [Background technology]

[0002] Patent Document 1 discloses that the gap between the inner and outer shells of a double-shell tank is pressurized or depressurized, and the presence or absence of damage to the outer shell is determined based on a pressure sensor that detects pressure fluctuations in the gap. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-202827 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology disclosed in Patent Document 1 does not take into consideration the function of the double-shell tank when it is damaged.

[0005] Therefore, in one aspect, the present invention aims to provide a double-shell tank or the like that takes into consideration its functionality when damaged. [Means for solving the problem]

[0006] In one embodiment, The inner tank contains an aqueous solution, and the outer tank contains pure water. A double-shelled tank is provided in which the pressure of the pure water is higher than the pressure of the aqueous solution.

[0007] In another aspect, a control unit is provided for controlling the amount of aqueous solution in the inner tank of the double-shelled tank and the amount of pure water in the outer tank of the double-shelled tank, The control unit controls the amounts of the aqueous solution and the pure water so that the pressure of the pure water is higher than the pressure of the aqueous solution.

[0008] In another embodiment, an aqueous solution is contained in the inner tank of the double-shelled tank, and pure water is contained in the outer tank of the double-shelled tank, A method for using a double-shell tank is provided, wherein the pressure of the pure water is made higher than the pressure of the aqueous solution. [Effects of the Invention]

[0009] According to one aspect, the present invention can provide a double-walled tank or the like that takes into consideration its functionality when damaged. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a double-shell tank according to the present embodiment. [Figure 2] FIG. 1 is a diagram showing an example of the configuration of a treatment system involving a double-shell tank. [Figure 2A] FIG. 10 is a diagram showing an example of the configuration of a processing system in which the inner tank and the outer tank are sealed. [Figure 3] FIG. 10 is a diagram showing a method for controlling the pressure of the aqueous solution and the pure water. [Figure 3A] FIG. 10 is a diagram showing a method for controlling the pressure of the aqueous solution and the pure water. DETAILED DESCRIPTION OF THE INVENTION

[0011] FIG. 1 is a diagram showing the configuration of the double-shell tank of this embodiment.

[0012] As shown in FIG. 1, the double-shell tank 10 of this embodiment includes an inner tank 11 and an outer tank 12 disposed around the inner tank 11. The inner tank 11 is disposed inside the inner shell 11A, and the outer tank 12 is disposed between the inner shell 11A and an outer shell 12A formed on the outer periphery of the inner shell 11A. The inner tank 11 and the outer tank 12 may each be of an open type or a closed type. Note that, since the pressure difference between the inner tank 11 and the outer tank 12 does not need to be large, the inner shell 11A does not necessarily need to be robust in terms of pressure resistance. Therefore, for example, the inner shell 11A may be formed of a membrane structure.

[0013] In this embodiment, the inner tank 11 contains an aqueous solution, and the outer tank 12 contains pure water. The aqueous solution in the inner tank 11 is managed by an aqueous solution treatment facility 21, and the pure water in the outer tank 12 is managed by a pure water treatment facility 22. The content of management by the aqueous solution treatment facility 21 and the pure water treatment facility 22 is arbitrary, but at least the aqueous solution in the inner tank 11 is supplied and drained via the aqueous solution treatment facility 21, and the pure water in the outer tank 12 is supplied and drained via the pure water treatment facility 22.

[0014] FIG. 2 is a diagram showing an example of the configuration of a treatment system relating to a double-walled tank.

[0015] As shown in FIG. 2, the processing system 50 includes a control unit 51 and a detection unit 52.

[0016] The control unit 51 controls the pressure difference between the aqueous solution in the inner tank 11 and the pure water in the outer tank 12 via the water supply and drainage operations of the aqueous solution treatment equipment 21 and the pure water treatment equipment 22. Specifically, the control unit 51 controls the water level of the aqueous solution in the inner tank 11 and the water level of the pure water in the outer tank 12 so that the pressure of the pure water in the outer tank 12 is higher than the pressure of the aqueous solution in the inner tank 11.

[0017] 2, the control unit 51 constantly acquires the water level of the aqueous solution in the inner tank 11 from the water level sensor 41 provided in the inner tank 11, and constantly acquires the water level of the pure water in the outer tank 12 from the water level sensor 42 provided in the outer tank 12. Furthermore, the control unit 51 controls the amounts of water supply and discharge by the aqueous solution treatment facility 21 and the pure water treatment facility 22, for example, so that the water levels of the aqueous solution and the pure water respectively reach predetermined target water levels.

[0018] If the inner tank 11 or the outer tank 12 is a sealed type, a pressure sensor can be used instead of or in addition to the water level sensor 41 or the water level sensor 42. In this case, the control unit 51 controls the operation of the pump provided in the inner tank 11 or the outer tank 12 so that the pressure inside the inner tank 11 or the outer tank 12 becomes the target pressure.

[0019] FIG. 2A is a diagram showing an example of the configuration of a processing system in which the inner tank and the outer tank are sealed.

[0020] 2A, there are provided pressure sensors 81 and 82 that detect the pressures in the inner tank 11 and the outer tank 12, respectively, and pumps 91 and 92 that pressurize the inner tank 11 and the outer tank 12, respectively. In this case, the control unit 51 acquires the pressures in the inner tank 11 and the outer tank 12 detected by the pressure sensors 81 and 82. The control unit 51 may also control the operation of the pumps 91 and 92 so as to bring the acquired pressures in the inner tank 11 and the outer tank 12 closer to their respective target pressures.

[0021] Furthermore, in this embodiment, the detection unit 52 can detect damage to the inner shell 11A and the outer shell 12A based on the water level or pressure of the inner tank 11 or the outer tank 12 acquired by the control unit 51. For example, if a crack occurs in the outer shell 12A, the water level or pressure in the outer tank 12 changes in a direction corresponding to the external pressure (e.g., groundwater pressure). Furthermore, if a crack occurs in the inner shell 11A, the water level difference or pressure difference between the inner tank 11 and the outer tank 12 changes in a direction that reduces it. Therefore, the detection unit 52 can detect damage to the inner shell 11A and the outer shell 12A based on these phenomena. Specifically, after the sensors (water level sensors 41, 42, pressure sensors 81, 82, etc.) detect the drop in water level or pressure, the presence or absence of damage to the inner tank 11 or the outer tank 12 (inner shell 11A or outer shell 12A) can be determined based on the operation information of the water supply and pressure pumps (pumps 91 and 92, etc.) in the aqueous solution treatment equipment 21 or the pure water treatment equipment 22 that is fed back to the control unit 51. For example, if the water level in the inner tank 11 or the outer tank 12 drops due to water evaporation, the water level and pressure will recover if the water supply and pressure pumps are operated for a short period of time. Therefore, in this case, it can be determined that there is no damage to the inner tank 11 or the outer tank 12 (inner shell 11A or outer shell 12A). On the other hand, if there is a water leak, the water supply and pressure pumps will operate for a long period of time. Therefore, in this case, it can be determined that there is damage to the inner tank 11 or the outer tank 12 (inner shell 11A or outer shell 12A). A threshold value related to the operational information for determining whether or not there is damage may be set in advance, and the presence or absence of damage may be determined using the set value. This threshold value may be a value that varies depending on the environmental temperature and humidity. The detection unit 52 can detect damage to both the inner tank 11 and the outer tank 12 (inner shell 11A or outer shell 12A) independently, but may also detect damage to only one of the inner tank 11 or the outer tank 12 (inner shell 11A or outer shell 12A).

[0022] 3 and 3A are diagrams showing a method for controlling the pressure of the aqueous solution and the pure water. In FIGS. 3 and 3A, the vertical axis represents the water level (height) of the aqueous solution and the pure water, and the horizontal axis represents the pressure (water pressure) of the aqueous solution and the pure water. The state of the aqueous solution is indicated by line 61, and the state of the pure water is indicated by line 62 (FIG. 3) and line 72 (FIG. 3A), respectively.

[0023] When the specific gravity of the aqueous solution is substantially equal to that of pure water, the pressures of the aqueous solution and pure water correspond to their respective water levels, and the pressures are the same when the water levels are the same, as shown by lines 61 and 62 in Fig. 3. Therefore, the target water level of the pure water is set higher than the target water level of the aqueous solution, and the control unit 51 controls the water level of the pure water to be higher than the water level of the aqueous solution.

[0024] If the specific gravity of the aqueous solution is greater than that of pure water, the pressure of the aqueous solution will be lower than the pressure of pure water even at the same water level, as shown by lines 61 and 72 in Figure 3A. For this reason, it is necessary to set the target water level of the aqueous solution higher.

[0025] If the outer tank 12 is a sealed type and the pressure is insufficient even when the water level reaches the upper limit, pressurization can be performed using a pump. In Fig. 3A, line 72a shows the change in state of the pure water when the pressure increases due to a rise in the water level, and line 72b shows the change in state of the pure water when the pressure increases due to pressurization.

[0026] Next, the function of the double-shell tank 10 will be described.

[0027] The double-shell tank 10 can be widely used when an aqueous solution is stored in the inner tank 11. The aqueous solution may have any composition, but as an example, an application to an aqueous gadolinium solution will be described.

[0028] One type of observation facility for neutrinos and other elementary particles, as well as cosmic rays, is to install a huge water tank underground and observe the luminous phenomenon (Cherenkov radiation) inside it. At Super-Kamiokande, a facility of this type, observations were previously carried out using ultrapure water stored in the tank, but now an aqueous gadolinium solution is used. While there are no legal restrictions on gadolinium, such as environmental or emission standards, its impact on the natural environment has not yet been fully verified, and careful handling is required.

[0029] When the double-shell tank 10 is applied to such a facility, the following advantages can be obtained.

[0030] First, if a crack were to occur in the inner shell 11A due to an accident, deterioration, earthquake, or the like, pure water would simply flow into the inner tank 11, and no impurities would be mixed in. Furthermore, a crack in the inner shell 11A can be detected by fluctuations in the water level in the inner tank 11 or the outer tank 12. In this case, observations can be continued as long as the pressure difference between the inner tank 11 and the outer tank 12 can be maintained by supplying and discharging water to and from the inner tank 11 and the outer tank 12.

[0031] Similarly, if a crack occurs in the outer shell 12A, pure water will simply leak out, preventing contamination of the surrounding environment. Furthermore, a crack in the outer shell 12A can be detected by fluctuations in the water level and pressure in the outer tank 12. In this case, observations can be continued as long as the pressure difference between the inner tank 11 and the outer tank 12 can be maintained by supplying water to the outer tank 12.

[0032] As described above, according to this embodiment, even if the inner shell 11A or the outer shell 12A is damaged, the functionality of the double-walled tank 10 can be ensured to some extent. For example, even if a crack occurs in the inner shell 11A or the outer shell 12A, it is possible to prevent impurities from entering the inner tank 11A and adversely affecting the outside.

[0033] Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the claims. In addition, it is also possible to combine all or a plurality of components of the above-described embodiments. [Explanation of symbols]

[0034] 10 Double-shell tank 11 Inner tank 12 Outer Tank 50 Processing Systems 51 Control section 52 Detection unit

Claims

1. The inner tank contains an aqueous solution, and the outer tank contains pure water. The double-shell tank, wherein the pressure of the pure water is higher than the pressure of the aqueous solution.

2. a control unit for controlling a pressure difference between the aqueous solution and the pure water in a double-shell tank, the double-shell tank having an inner tank containing an aqueous solution and an outer tank containing pure water, The control unit controls the pressure of the pure water so that the pressure of the pure water is higher than the pressure of the aqueous solution.

3. The processing system according to claim 2 , further comprising a detection unit that detects damage to the inner tank or the outer tank based on the pressure of the aqueous solution or the pure water.

4. The inner tank of the double-shelled tank contains an aqueous solution, and the outer tank of the double-shelled tank contains pure water, A method for using a double-shell tank, wherein the pressure of the pure water is made higher than the pressure of the aqueous solution.

5. 5. The method for using a double-shell tank according to claim 4, wherein the pressure of the pure water is controlled so as to be higher than the pressure of the aqueous solution.

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