Water treatment device and water treatment method

Abstract

To provide a water treatment device and a water treatment method for performing water treatment for efficiently reducing the concentration of heavy water included in water of a treatment object.SOLUTION: A water treatment device (15) for reducing the concentration of heavy water included in water (Wa) of a treatment object includes: a flow channel part (3) including a flow channel (3a) through which water to be treated is made to flow and a filter medium (31) for filtering the water so as to discharge a portion of water from the flow channel; a first magnetic field generation part (2) for generating a static magnetic field in the flow channel part; a second magnetic field generation part (4) for generating an AC magnetic field having resonance frequency at which heavy hydrogen causes nuclear magnetic resonance in the static magnetic field in the flow channel part; and an electric field generation part (4) for generating an AC electric field having resonance frequency in the flow channel part. The filter medium in the flow channel part is provided with pores (30) having a size in which water molecules can rotate in accordance with the AC electric field.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a water treatment apparatus and a water treatment method for reducing the concentration of heavy water contained in water to be treated, such as cooling water for nuclear fuel in nuclear power generation. [Background technology]

[0002] Heavy water consists of water molecules that contain one or more deuterium atoms instead of hydrogen, and is found in common water in nature along with light water. For example, Patent Document 1 lists two conventional methods for reducing the amount of heavy water (including semi-heavy water) from common water: a method that uses repeated distillation and a method that uses water electrolysis, taking advantage of the very slight difference in physical properties between hydrogen and deuterium.

[0003] Patent Document 1 discloses a method for producing deuterium-reduced water by removing heavy water from water. This method for producing deuterium-reduced water involves supplying water vapor to a predetermined adsorbent at a pressure that causes heavy water to be adsorbed by the adsorbent but light water to be difficult to adsorb, thereby adsorbing the heavy water, and recovering the water vapor that is not adsorbed by the adsorbent. This makes it possible to produce deuterium-reduced water easily and at low cost. The adsorbent is formed, for example, from a material that is classified as type IV or type V in the IUPAC (International Union of Pure and Applied Chemistry) classification of water vapor adsorption isotherms. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 031896 [Non-patent literature]

[0005] [Non-Patent Document 1] Takanori Mori and three others, "Tracking the Melting Phenomenon of Ice Formed in Mesopores by NMR," News from the Low Temperature Center of Osaka University, 141, pp. 11-15, 2008-01 Summary of the Invention [Problem to be solved by the invention]

[0006] In the method of Patent Document 1, water is treated in a vaporized state, making it difficult to remove heavy water from water in large quantities. With conventional technology, it has been difficult to efficiently treat water to reduce the concentration of heavy water in a large flow rate of the target water, such as the cooling water mentioned above.

[0007] An object of the present invention is to provide a water treatment apparatus and a water treatment method that can efficiently perform water treatment to reduce the concentration of heavy water contained in the water to be treated. [Means for solving the problem]

[0008] In one aspect of the present invention, a water treatment device for reducing the concentration of heavy water in water to be treated includes a flow path section including a flow path through which the water to be treated flows and a filtration material that filters the water so as to discharge a portion of the water from the flow path, a first magnetic field generator that generates a static magnetic field in the flow path section, a second magnetic field generator that generates an AC magnetic field in the flow path section having a resonant frequency at which deuterium undergoes nuclear magnetic resonance in the static magnetic field, and an electric field generator that generates an AC electric field in the flow path section having the resonant frequency. The filtration material in the flow path section has pores that are sized to allow water molecules to rotate in response to the AC electric field.

[0009] In one aspect, the strength of the static magnetic field, the size of the pore, the material of the filtration material, and the temperature of the water to be treated may be set so that the resonant frequency is within the full width at half maximum range of the distribution of the rotational frequencies of the water molecules in the pore.

[0010] In one aspect, the electric field generator may be a plurality of electrodes facing each other across the flow path in a direction intersecting a magnetic flux direction of the static magnetic field.

[0011] In one aspect, the second magnetic field generating unit may be at least one coil that is arranged at a position different from the plurality of electrodes around the flow path unit.

[0012] In one embodiment, the at least one coil may be a plurality of coils that face each other across the flow path and each have a saddle-shaped configuration.

[0013] In one aspect, a capacitor formed by the plurality of electrodes and the coil may be electrically connected to each other as a resonant circuit that resonates at the resonant frequency.

[0014] In one aspect, the first magnetic field generating unit may be at least one superconducting magnet having a hollow shape, the flow path unit is disposed inside the superconducting magnet, and the capacitor and the coil are disposed between the flow path unit and the superconducting magnet.

[0015] In one aspect, the at least one superconducting magnet may be a plurality of superconducting magnets each having a hollow shape. The flow path portion, the capacitor, and the coil are arranged inside each superconducting magnet. The resonant circuits corresponding to the capacitors and the coils in each superconducting magnet are connected to each other as a ladder circuit.

[0016] In one aspect, the water treatment device may further include a control pump inserted between an external water channel system that supplies the water to be treated to a heat source as cooling water and the flow path section, and that adjusts the water pressure flowing from the water channel system into the flow path section and the water pressure flowing from the flow path section to the water channel system.

[0017] In one embodiment, the control pump may be a plurality of screw pumps connected in parallel.

[0018] In one aspect, the water treatment device may further include a power supply unit that supplies AC power to the electric field generator so as to generate the AC electric field intermittently.

[0019] In one aspect, the flow path section may be connected to the waterway system so as to divert the water from an external waterway system through which the water to be treated circulates and return the diverted water to the waterway system via the flow path.

[0020] In one aspect, the water treatment device may further include a first flow path through which the target water flows and a second flow path through which external water different from the target water flows, the first flow path and the second flow path being adjacent to each other via the filtration material.

[0021] In one embodiment, the filtration material may include a plurality of hollow fibers, and the flow path section has a piping structure in which the water to be treated flows through the interiors of the plurality of hollow fibers as the first flow path, and the outside water flows through the exterior of the hollow fibers in the flow path section as the second flow path.

[0022] In one embodiment, the filtration medium may comprise a porous material that exhibits a greater increase and decrease in adsorption amount than Types IV and V of the IUPAC classification within a narrower relative pressure range in a given adsorption isotherm.

[0023] In one aspect, a water treatment method for reducing the concentration of heavy water contained in water to be treated includes flowing the water to be treated through a flow path section having a flow path and a filtration material, generating a static magnetic field in the flow path section, generating an alternating current magnetic field in the flow path section having a resonant frequency at which deuterium undergoes nuclear magnetic resonance in the static magnetic field, generating an alternating current electric field in the flow path section having the resonant frequency, and rotating water molecules in pores provided in the filtration material in the flow path section in accordance with the alternating current electric field, thereby filtering the water so as to discharge a portion of the water containing the heavy water in the filtration material. [Effects of the Invention]

[0024] According to the water treatment device and water treatment method of the present invention, water treatment can be carried out efficiently to reduce the concentration of heavy water contained in the water to be treated. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram illustrating a cooling system to which a water treatment device according to a first embodiment of the present invention is applied; [Figure 2] Schematic diagram for explaining the basic principle of the water treatment method according to the first embodiment. [Figure 3] Graph illustrating frequency characteristics of dielectric loss in water to be treated by a water treatment method [Figure 4] 1 is a cross-sectional view showing a configuration example of a water treatment device according to a first embodiment; [Figure 5] FIG. 1 is a transparent perspective view illustrating the configuration of a superconducting magnet in a water treatment device. [Figure 6] FIG. 10 is a transparent perspective view illustrating the structure of an electromagnetic field converter in a water treatment device; [Figure 7] Circuit diagram for explaining a resonant circuit of an electromagnetic field converter in a water treatment device [Figure 8] FIG. 1 is a circuit diagram illustrating a resonant circuit of a modified example of the water treatment device; [Figure 9] Schematic diagram showing a modified example of a control pump in a water treatment device. [Figure 10] Graph for explaining intermittent control in a water treatment device [Figure 11] Schematic cross-sectional view showing a configuration example of a water treatment device according to a second embodiment. [Figure 12] Schematic cross-sectional view of line AA in Figure 11 [Figure 13] 10 is a cross-sectional view showing a modified example of the water treatment device according to the second embodiment. [Figure 14] Graph for explaining modified examples of the filter material of the water treatment device DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiments are provided as examples to embody the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to these embodiments.

[0027] (Embodiment 1) In the first embodiment, an example will be described in which the present invention is applied to water treatment technology for cooling nuclear fuel and the like in various facilities related to nuclear power generation (hereinafter referred to as "nuclear facilities").

[0028] 1. Cooling systems for nuclear facilities An application example of the water treatment device according to the first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 illustrates a cooling system 10 to which a water treatment device 15 according to this embodiment is applied.

[0029] 1, the cooling system 10 includes a heat source 12 storing nuclear fuel 11, a circulating water channel system 13 that circulates cooling water Wa to the heat source 12, and a water treatment device 15 according to this embodiment in a nuclear facility 1. The cooling system 10 is a system that cools the heat source 12 by circulating the cooling water Wa in, for example, the nuclear facility 1. In the example of FIG. 1, the water treatment device 15 according to this embodiment is incorporated into a flow path that bypasses the cooling water Wa from the circulating water channel system 13 of the cooling system 10.

[0030] The cooling water Wa is an example of water to be treated by the water treatment device 15 in this embodiment, and includes heavy water and light water. Heavy water is composed of various water molecules (HDO, DO) that contain deuterium (D), an isotope of hydrogen (H), while light water is composed of water molecules (HO) that do not contain any hydrogen isotopes. For example, the concentration of heavy water in the cooling water Wa is specified by, for example, mass percent concentration or molar concentration.

[0031] The cooling system 10 of this embodiment can be applied to nuclear facilities 1, such as boiling water nuclear power plants, decommissioning facilities converted from nuclear power plants, and storage pool facilities for spent nuclear fuel. The cooling system 10 of this embodiment can be applied to nuclear facilities 1 having various types of nuclear reactors, such as nuclear fusion reactors, in addition to nuclear fission reactors.

[0032] The heat source 12 in the nuclear facility 1 is, for example, a pressure vessel that stores usable nuclear fuel 11, or a fuel pool that stores spent nuclear fuel 11. The circulating water channel system 13 of the cooling system 10 includes various structures and mechanisms that supply cooling water Wa to the heat source 12, such as water channel pipes, a circulating pump, and a condenser.

[0033] There is concern that the cooling water Wa in the nuclear facility 1 may become activated by exposure to neutrons emitted by the nuclear fuel 11, resulting in the generation of tritium, a radioactive isotope of hydrogen. This activation does not occur when hydrogen is directly converted to tritium in the cooling water Wa, but rather when deuterium, a non-radioactive isotope of hydrogen, is converted to tritium through a nuclear reaction. For example, the concentration of tritiated water in the cooling water Wa (after the nuclear reaction) may be proportional to the square of the concentration of heavy water in the cooling water Wa (before the nuclear reaction).

[0034] Therefore, the water treatment device 15 according to this embodiment performs a water treatment method to reduce the concentration of heavy water contained in the cooling water Wa. This suppresses the generation of tritium in the cooling water Wa exposed to neutron rays, thereby reducing activation of the cooling water Wa. In this way, safety regarding activation of the cooling water Wa in the nuclear facility 1 can be improved.

[0035] The water treatment device 15 of this embodiment can suppress the generation of tritium even in the cooling water Wa that cools the spent nuclear fuel 11, and is therefore useful, for example, in a decommissioning scenario when a nuclear power plant has exceeded its useful life (for example, 40 years). For example, in a decommissioning scenario, the spent nuclear fuel 11 will be stored in a wet environment such as a fuel pool for a cooling period of more than ten years, and then stored in a dry environment.

[0036] By introducing the water treatment device 15 of this embodiment, it becomes possible to realize a decommissioning method in which the nuclear facility 1 to be decommissioned itself is renovated by, for example, converting it into a sarcophagus so that it can be used as a wet storage facility. In this case, even when the facility is directly transferred to dry storage, the generation of radioactive tritiated water can be suppressed, making the transfer construction and the like easier.

[0037] 2. Basic principles of reducing heavy water concentration The basic principle of how the concentration of heavy water is reduced in the water treatment device 15 and the water treatment method of this embodiment will be described with reference to FIGS.

[0038] Fig. 2 is a schematic diagram for explaining the basic principle of the water treatment method according to the present embodiment. Fig. 3 is a graph illustrating the frequency characteristics of the dielectric loss in the water to be treated by the water treatment method.

[0039] To reduce the concentration of heavy water in water to be treated, such as the cooling water Wa, the water treatment device 15 of this embodiment employs the basic principle of selectively exciting heavy water using magnetic fields Ba and Bb and an electric field Ea, as shown in Fig. 2. This basic principle can be reduced to a physical model that states that "if conditions are met to match the resonant frequencies of two types of resonance phenomena at different levels in the atomic-molecular interactions caused by electromagnetic fields, synchronous interlocking occurs via the weak coupling between the two, resulting in interlocking excitation in which the selective characteristics of the former are inherited by the latter resonance."

[0040] Specifically, the former resonance phenomenon is nuclear magnetic resonance (NMR) using an alternating magnetic field Ba and a static magnetic field Bb, as shown in Fig. 2. The latter resonance phenomenon is electromagnetic excitation (i.e., dielectric heating) of the rotational degree of freedom of a water molecule as an electric dipole, for example, using an alternating electric field Ea.

[0041] In the former case, the hydrogen nuclei of light water, i.e., H nuclei, have a spin of "1 / 2," while the deuterium nuclei, i.e., D nuclei, have a spin of "1." Therefore, the NMR resonance frequency can be significantly different between light water and heavy water, e.g., 400 MHz for H nuclei and 70 MHz for D nuclei in a 10-tesla static magnetic field Bb. Therefore, in the water treatment device 15 of this embodiment, by appropriately setting the frequency of the alternating magnetic field Ba for NMR excitation, it is easy to selectively excite only heavy water, as shown in FIG. 2. The excited deuterium can weakly bind to the molecular rotation of heavy water during the spin-lattice relaxation, or T1 relaxation, process.

[0042] Regarding the latter, dielectric heating, as shown in Figure 3, the frequency characteristic F1 of free water, a normal liquid, has a peak frequency due to resonance caused by molecular rotation in the vicinity of 10 GHz, and is used in microwave oven technology, etc. In contrast, the dielectric constant characteristics of water have revealed that if water is confined within the nanopores of a porous material, for example, it is possible to obtain frequency characteristics C2 of confined water, with the peak frequency reduced to several tens of MHz at room temperature, as shown in Figure 3. This behavior is due to the electric dipole water molecules behaving as a group through hydrogen bonds.

[0043] Therefore, the water treatment device 15 of this embodiment uses a porous material as a filter material for filtering heavy water, and is configured so that water molecules become bound water within the pores 30 (Figure 2). In this configuration, water molecules (whether light water or heavy water) move downstream while repeatedly adsorbing and desorbing from the inner wall, similar to, for example, a capillary in liquid chromatography. In this case, the migration speed is determined by the residence time between adsorption and desorption, and increases as the difference between the physical adsorption energy (less than eV) and the thermal disturbance energy proportional to the liquid temperature increases. Therefore, the water treatment device 15 of this embodiment provides the heavy water molecules with an energy difference ΔP (Figure 2) that promotes desorption by exciting the two types of resonance phenomena described above in conjunction with each other.

[0044] In this embodiment, the weak coupling between the Larmor rotation of D nuclei due to NMR and the rotation of the electric dipoles of heavy water molecules due to dielectric heating accelerates and decelerates the latter rotation, promoting synchronous rotation. This is very similar to the operation of a synchronous motor, where the rotor is accelerated and decelerated by the rotating magnetic field generated in the stator, resulting in synchronization. The latter molecular rotation can also occur thermally (i.e., with various phases, speeds, and rotation directions) depending on, for example, the ambient temperature, but the closer the rotation speed is to the former rotation speed, the more pronounced the acceleration and deceleration effect. This synchronization phenomenon has been revealed in research on bound water using NMR relaxation time (e.g., Non-Patent Document 1).

[0045] Non-Patent Document 1 examines the rotational state of water molecules by saturated adsorption of water molecules into existing mesoporous silica with a pore size of 2.7 nanometers and measuring the relaxation time for the excited state to decay from the NMR spectroscopic analysis spectrum. In this case, when the rotational speed of the water molecules is changed using water temperature as a parameter, a phenomenon is observed in which the relaxation time becomes shorter like a resonance curve (i.e., the interaction becomes greater) when the rotational speed is close to the NMR resonance frequency. This indicates that energy transfer from NMR Larmor rotation to water molecule rotation (i.e., synchronization from acceleration and deceleration) occurs.

[0046] Here, Non-Patent Document 1 aims at analysis for material research, and uses pulsed (Fourier) NMR for nuclear magnetic resonance (NMR). Specifically, to minimize disturbance to the target system caused by the excitation pulse, the product of the excitation pulse width and frequency (i.e., duty) is kept as low as possible, and excitation is performed with a short-term wave packet of a radio-frequency magnetic field as an almost single pulse, and the subsequent response echo signal is measured with high sensitivity. This is because if the pulse frequency were high, echoes with different timing would overlap, degrading the signal-to-noise ratio. This cycle is repeated to accumulate and average minute signals, and measurements are performed.

[0047] In contrast, in the water treatment device 15 of this embodiment, NMR is performed to excite as many deuterium atoms as possible and transfer the energy to the rotation of water molecules. For example, by relatively increasing the duty and making the radio frequency magnetic field closer to a continuous wave with successive pulses, it is possible to operate the device so that many D nuclei are successively excited by NMR and further re-excite D nuclei that have returned to the ground state.

[0048] If the above-described effect allows only the heavy water molecules to rotate in synchronization with the AC magnetic field Ba for NMR, the heavy water molecules can be vibrated as electric dipoles (i.e., excited and heated) by an AC electric field Ea simultaneously obtained from, for example, the high-frequency power of the source of the AC magnetic field Ba. In the water treatment device 15 of this embodiment, the AC electric field Ea is set, for example, perpendicular to the magnetic flux of the static magnetic field Bb in order to match the direction of rotation of the heavy water molecules caused by NMR.

[0049] In the water treatment device 15, the rotation of water molecules adsorbed to the filtration material is damped by physical adsorption energy and the like due to the attractive force of proximity interaction with the inner walls of the pores 30. If the excitation (heating) by the AC electric field Ea overcomes this damping, the desorption of the adsorbed water molecules is promoted. Therefore, the selective excitation of heavy water molecules in the water treatment device 15 of this embodiment shortens the residence time of heavy water molecules from adsorption to desorption, and as a result, the movement speed of heavy water molecules within the pores increases, thereby improving the permeability of heavy water through the filtration material.

[0050] The water treatment device 15 of this embodiment operates with a device configuration based on the conditions for aligning the former and latter resonance frequencies within a predetermined range. The predetermined range is a range in which the two frequencies are aligned to an accuracy within the latter full width at half maximum 2Δω (FIG. 3), for example, and is set appropriately taking into account the allowable error. As parameters for such setting, the NMR resonance frequency depends on the strength of the static magnetic field Bb, and the rotational frequency of water molecules depends on the confinement space (i.e., the pore size of the porous filter material) and the liquid temperature.

[0051] In this embodiment, water treatment is performed by configuring the water treatment device 15 so that these parameters satisfy the above-mentioned conditions, and by supplying high-frequency power of the corresponding frequency to simultaneously generate an AC magnetic field Ba and an AC electric field Ea, a process for selectively removing heavy water can be achieved. In summary, this process involves selective excitation of deuterium by NMR, followed by selective dielectric heating of heavy water molecules by dipole rotation via the T1 relaxation process, allowing the heavy water to selectively pass through the filter material. For example, in addition to the solution disclosed in Non-Patent Document 1, solutions that satisfy the above-mentioned conditions, when modified to accommodate room temperature water, include solutions in which the static magnetic field Bb strength is several teslas or more, the resonant frequency is several megahertz or more, and the pore size is several nanometers or less in diameter.

[0052] 3. Water treatment equipment The configuration and operation of water treatment device 15 according to this embodiment, which is based on the above-described basic principles, will be described in detail below. Fig. 4 shows an example of the configuration of water treatment device 15 according to this embodiment. Fig. 4 shows a schematic cross section of water treatment device 15 to illustrate its configuration.

[0053] In this configuration example, the water treatment device 15 is configured to effectively discharge heavy water molecules into the external water Wb in order to reduce the heavy water concentration in the cooling water Wa to be treated. The external water Wb is an example of external water that is supplied from outside the cooling system 10 (FIG. 1), for example. The external water Wb can be discharged to the outside, such as the ocean, via the flow path 3, for example.

[0054] 4, the water treatment device 15 of this embodiment includes a superconducting magnet 2 (see FIG. 5) having a hollow shape, a flow path section 3 arranged inside the superconducting magnet 2, and an electromagnetic field converter 4 arranged between the superconducting magnet 2 and the flow path section 3. Furthermore, the water treatment device 15 of this configuration example includes a control pump 5 inserted between the circulating water channel system 13 of the cooling system 10 (FIG. 1) and the flow path section 3, and a power supply section 6 electrically connected to the electromagnetic field converter 4.

[0055] The electromagnetic field converter 4 is a device that generates an AC electric field Ea and an AC magnetic field Ba in accordance with an AC frequency such as a high frequency contained in the power supplied from the power supply unit 6. Details of the electromagnetic field converter 4 will be described later.

[0056] The control pump 5 is a self-pressure regenerating pump (bidirectional pressurization / depressurization parallel) for adjusting the pressure difference between the cooling water Wa circulating to the heat source 12 in the circulating water channel system 13 (FIG. 1) and the cooling water Wa to be treated flowing upstream of the filtration membrane 31 in the flow path section 3 (FIG. 4). Details of the control pump 5 will be described later.

[0057] The power supply unit 6 includes an AC power supply that generates power at an AC frequency such as high frequency, and a control circuit that controls the supply timing and AC frequency of the high frequency power, etc. For example, the power supply unit 6 includes various power converters such as an inverter and a converter.

[0058] FIG. 5 illustrates the configuration of the superconducting magnet 2 in the water treatment device 15. The superconducting magnet 2 generates a uniform static magnetic field Bb in, for example, a hollow inner space. The superconducting magnet 2 includes, for example, a solenoid coil, a cooler, and a control circuit. Existing engineering technologies developed for various other purposes, such as a superconducting energy storage system (SMES), can be appropriately applied to the superconducting magnet 2. The superconducting magnet 2 is an example of a first magnetic field generating unit in this embodiment.

[0059] The flow path section 3 is a part that forms a flow path 3a through which water to be treated, such as cooling water Wa, flows in the water treatment device 15, and is formed of, for example, a tubular member. In this configuration example, the flow path section 3 includes, in addition to the flow path 3a for the cooling water Wa, a flow path 3b through which, for example, downstream water Wb flows as a counterflow to the cooling water Wa.

[0060] The flow path section 3 of this embodiment includes a filter membrane 31, which is an example of a filtering material having the above-described pores 30 (FIG. 2). In the flow path section 3 of this configuration example, for example, in a cooling system 10 (FIG. 1), a flow path 3a for cooling water Wa circulating between the heat source 12 and the water treatment device 15 and outside water Wb, which is constantly replaced from the outside, are separated by the filter membrane 31 having pores with a diameter of several nanometers or less.

[0061] In the flow path section 3 of this example, the filtration membrane 31 is held in a uniform static magnetic field Bb of several teslas or more generated by the superconducting magnet 2. The water treatment device 15 of this example is configured so that an AC magnetic field Ba and an AC electric field Ea are generated in the flow path section 3 by the electromagnetic field converter 4 based on high-frequency power of several megahertz or more. For example, the flow path section 3 is made of a material that can introduce the various electromagnetic fields Ea, Ba, and Bb applied from the outside as described above into the interior without blocking them.

[0062] Furthermore, to prevent the AC electric field Ea from being obstructed even when the electrodes (described below) of the electromagnetic field converter 4 are disposed near the flow path 3, the materials of the container holding the filtration membrane 31 in the flow path 3 are nonmagnetic so that the magnetic fields Ba and Bb can reach the interior, as well as insulating and nondielectric. Examples of materials for the flow path 3 with such properties include resin-based structural materials, inorganic Pyrex (fused silica), and composites thereof such as fiber-reinforced plastics (FRP), glass-fiber-reinforced plastics (GRP), and carbon-fiber-reinforced plastics (CRP). Examples of the resin-based structural materials include Teflon (registered trademark), vinyl chloride, ABS (acrylonitrile butadiene styrene), PEN (polyethylene naphtahalate), polycarbonate, and cellulose.

[0063] To realize the above-described basic principle, various porous materials having desired pore sizes can be appropriately used as the filtering material such as the filtration membrane 31. For example, possible filtering materials include mesoporous silica such as silica gel, FSM-16 (Folded Structure of Mesoporous material 16), and MCM-41 (Mobil Crystalline Material 41).

[0064] Since the pore size of MCM-41 can be changed by approximately several nanometers by changing the alkyl chain length of the template surfactant, it is possible to design the material so that the rotational frequency of water molecules becomes an appropriate value. Furthermore, from the viewpoint of ensuring as large an effective area as possible of the filtration membrane 31 separating the two flow paths 3a, 3b, the filtration membrane 31 may have a three-dimensional structure such as the hollow fibers found in water purifiers and artificial dialysis machines, or the scroll-type structure of a reverse osmosis seawater desalination device.

[0065] By operating the water treatment device 15 of this configuration example, when light water and heavy water in the cooling water Wa pass through the pores 30 of the filtration membrane 31, only the D nuclei of the heavy water molecules are excited by nuclear magnetic resonance, and the T1 relaxation phenomenon immediately accelerates or decelerates the thermal rotation of the heavy water molecules, promoting synchronous rotation (see Figure 2). As a result, the heavy water molecules are also synchronized with the AC electric field Ea that is generated at the same time, and the excitation (heating) of this field promotes desorption, making it easier for only the heavy water molecules to pass through the pores 30 in a short period of time.

[0066] This operation of the water treatment device 15 can increase the filtration efficiency of heavy water in the treatment of cooling water Wa using various electromagnetic fields Ea, Ba, and Bb. The above operation can be achieved by synchronizing and simultaneously linking the nuclear magnetic resonance of the D nucleus caused by the AC magnetic field Ba generated within the pores 30 of the filtration membrane 31 with the vibrational resonance of the dipole rotation of heavy water molecules caused by the AC electric field Ea using single-frequency high-frequency power.

[0067] 3-1. Electromagnetic field converter The electromagnetic field converter 4 in the water treatment device 15 of this embodiment will be described in detail with reference to FIGS.

[0068] 6 illustrates the structure of the electromagnetic field converter 4 in the water treatment device 15 of this embodiment. FIG. 7 is a circuit diagram for explaining the resonant circuit 40 of the electromagnetic field converter 4.

[0069] The electromagnetic field converter 4 of this embodiment includes a pair of saddle coils 41 and a pair of opposing electrodes 42, as shown in FIG.

[0070] As shown in Fig. 6, for example, a pair of saddle coils 41 are arranged facing each other around the flow path section 3, sandwiching a position where the filtration membrane 31 is placed from a certain direction. When high-frequency power is supplied to the pair of saddle coils 41, an AC magnetic field Ba is generated within the pores 30 of the filtration membrane 31 (see Figs. 2 and 4). The saddle coil 41 of the electromagnetic field converter 4 is an example of a second magnetic field generator in this embodiment. Arranging the saddle coils 41 facing each other makes it easier to linearize the direction of the magnetic flux of the AC magnetic field Ba in the flow path section 3, for example.

[0071] The pair of opposing electrodes 42 are arranged to sandwich the filtration membrane 31 in a direction perpendicular to the magnetic flux of the AC magnetic field Ba and the magnetic flux of the static magnetic field Bb, for example, as shown in Fig. 6. The same high-frequency power as described above is also supplied to the pair of opposing electrodes 42, generating an AC electric field Ea synchronized with the AC magnetic field Ba within the pores 30 of the filtration membrane 31 (see Figs. 2 and 4). The pair of opposing electrodes 42 is an example of an electric field generator in this embodiment.

[0072] 7, the electromagnetic field converter 4 of this embodiment forms an LC ladder-type resonant circuit 40 consisting of an inductance L of a pair of saddle coils 41 and a capacitance C of a capacitor formed by a pair of opposing electrodes 42. By supplying high-frequency power to such a resonant circuit 40, an AC magnetic field Ba and an AC electric field Ba of the same frequency can be easily generated simultaneously within the pores 30 of the filtration membrane 31.

[0073] 7 also shows equivalent circuits 40a and 40b for explaining the function of the resonant circuit 40 of the electromagnetic field converter 4. Hereinafter, L and C may be used to equate the circuit elements with the circuit constants.

[0074] Generating a strong AC magnetic field Ba from high-frequency power can be achieved, for example, by passing a large current through a coil 41. For this purpose, as shown in FIG. 7, for example, an LC parallel circuit 40a can be used, in which a coil (L) and a capacitor (C) are connected in parallel. In this case, the current flowing through the coil L becomes q times the external input current Iin by flowing back and forth between the coil L and the capacitor C. For example, q is expressed as q=ωL / r, where ω is the frequency, L is the inductance, and r is the coil resistance.

[0075] On the other hand, a strong AC electric field Ea can be generated by applying a high voltage between a pair of opposing electrodes 42 that sandwich the flow path section 3. For this purpose, for example, as shown in FIG. 7, an LC series circuit 40b in which a coil L and a capacitor C are connected in series can be used. In this case, the voltage across the capacitor C becomes a high voltage Q times the externally applied voltage Vin in response to the current that rapidly flows from the capacitor C to the coil L. This generates a strong AC electric field Ea in the region of the flow path section 3 sandwiched between the electrodes of the capacitor C.

[0076] According to the electromagnetic field converter 4 of this embodiment, a large current in the coil and a high voltage in the capacitor can be simultaneously generated using an LC ladder-type resonant circuit 40 that combines the above-mentioned LC parallel circuit 40a and LC series circuit 40b, as illustrated in Fig. 7. Furthermore, as illustrated in Fig. 6, the coil is a saddle-type coil 41 that sandwiches the flow path 3 incorporating the filtration membrane 31, and is sandwiched between a pair of opposing electrodes 42 so as to intersect with the coil, forming a capacitor. This allows a strong AC magnetic field Ba and a strong AC electric field Ea to be generated in the flow path 3 in synchronization with the high-frequency power.

[0077] In the electromagnetic field converter 4 of this embodiment, the inductance L and capacitance C are designed so that the resonant frequency of the resonant circuit 40 matches the resonant frequency (e.g., several tens to several hundred MHz) for selectively exciting heavy water as described above. In this case, the capacitance C of the pair of opposing electrodes 42 sandwiching the flow path section 3 incorporating the filtration membrane 31 is calculated taking into consideration that the relative dielectric constant of free water, which occupies most of the inside of the flow path section 3, is "approximately 60 (e.g., in the MHz band)." The inductance L can be calculated from the inner diameter and number of turns of the coil, treating the inside of the flow path section 3 as having a relative magnetic permeability of "1."

[0078] In the electromagnetic field converter 4 configured as described above, the Larmor rotation of deuterium excited by NMR due to the high-frequency AC magnetic field Ba has its axis of rotation in the direction of the static magnetic field Bb of the NMR (see FIG. 2). Then, in the T1 relaxation phenomenon, synchronous rotation is induced by the acceleration / deceleration effect due to binding only to heavy water molecules that thermally rotate on the same axis. The electric dipole heavy water molecules that have begun synchronous rotation are synchronously excited by the dielectric heating of the high-frequency AC electric field Ea that the electromagnetic field converter 4 of this embodiment simultaneously generates in the flow path 3.

[0079] As described above, the electromagnetic fields Ea and Ba from the electromagnetic field converter 4 cause dielectric heating to counteract the proximity interaction with the inner wall of the pore 30, thereby promoting the desorption of heavy water molecules. On the other hand, for the light water molecules present in large numbers in the flow path section 3, there is no synchronization of thermal rotation by NMR, so the effect of dielectric heating can be limited to only a very small number of molecules that happen to have the same phase.

[0080] The water treatment device 15 of this embodiment may include a plurality of electromagnetic field converters 4. For example, a plurality of systems for promoting heavy water filtration, each of which is a combination of a flow path unit 3 installed inside a superconducting magnet 2 and an electromagnetic field converter 4, may be arranged in parallel. This makes it easier to ensure a sufficient treatment volume per unit time when applied to cooling water Wa, which flows at a large flow rate during operation of a nuclear power plant, for example. The superconducting magnet 2 may be an existing configuration such as an SMES. For example, a configuration may be adopted in which a flow path unit 3 incorporating a filtration membrane 31 is inserted at the center of a plurality of solenoid coils used in an SMES.

[0081] Figure 8 illustrates a resonant circuit 40 of a modified example of the water treatment device 15. A plurality of electromagnetic field converters 4 in the parallel system configuration described above may be configured to form a resonant circuit 40 connected in series as a ladder circuit, for example, as shown in Figure 8. This allows the input supply of high-frequency power to be commonized to one location, simplifying the power supply configuration such as the power supply unit 6 (Figure 4).

[0082] 3-2. Control pump In an actual nuclear power plant, the pressure of the circulating cooling water Wa may fluctuate due to various operating conditions. In the water treatment device 15 of this embodiment, the control pump 5 stabilizes the selective permeability of heavy water in the filtration membrane 31 against such pressure fluctuations. The control pump 5 will be described in detail below.

[0083] 4, the control pump 5 includes a pressure reducing pump 51 that reduces the pressure of the cooling water Wa flowing from the circulating water channel system 13 to the flow path section 3, and a pressure increasing pump 52 that pressurizes the cooling water Wa flowing from the flow path section 3 to the circulating water channel system 13. In the example of FIG. 4, the control pump 5 is configured as a reciprocating pump in which the pressure reducing pump 51 and the pressure increasing pump 52 are connected so that the work performed by the two pumps is offset.

[0084] In the water treatment device 15 (FIG. 4), the speed and amount of cooling water Wa flowing through the pores 30 of the filtration membrane 31 are proportional to the pressure difference between the cooling water Wa to be treated upstream of the filtration membrane 31 and the external water Wb downstream. Therefore, in this embodiment, the pressure of the upstream cooling water Wa to be treated is adjusted and stabilized using, for example, the control pump 5 so that it is pressurized slightly relative to the external water Wb downstream of the filtration membrane 31. This improves the performance of the water treatment device 15 of this embodiment in selectively removing heavy water. Furthermore, by providing the water treatment device 15 with this pressure control function, it is easy to ensure flexibility in the operating pressure of the cooling water Wa in the circulating water channel system 13 located at the most upstream.

[0085] 3-2-1. Bypass routes 1, the water treatment device 15 of this embodiment is incorporated into a bypass path that thins out and diverts cooling water Wa from the main flow of the circulating water channel system 13 and returns it to the main flow. For example, pumps 51 and 52 (FIG. 4) of the control pump 5 in the water treatment device 15 are each connected to the bypass path of the circulating water channel system 13.

[0086] This allows for a configuration in which the large flow rate of cooling water Wa used to convert core heat into energy in succession through boiling, steam turbine power generation, and condensation, as in a nuclear power plant in operation, is thinned out through a bypass route to perform water treatment, making it easier to introduce the water treatment device 15 as ancillary equipment.

[0087] It should be noted that the water treatment device 15 of this embodiment does not necessarily have to be incorporated into the bypass path of the circulating water channel system 13. For example, the water treatment device 15 may be incorporated into the main flow of the circulating water channel system 13 as long as it is within an appropriate allowable range, taking into consideration the flow rate of the cooling water Wa in the cooling system 10 of the nuclear facility 1 to be introduced and the treatment amount of the water treatment device 15.

[0088] 3-2-2. Modified Control Pump In the above description, two connected reciprocating pumps have been shown as an example of the control pump 5 in the water treatment device 5 of this embodiment in Fig. 4, but screw pumps connected in parallel may be used instead. Such a modification will be described with reference to Fig. 9.

[0089] Figure 9 shows a modified example of the control pump 5 in the water treatment device 15. In this modification, the water treatment device 15 employs, for example, two linked screw pumps 5A as the control pump 5, as shown in Figure 9. This allows for continuous parallel operation of pressurization and depressurization, and reduces pressure fluctuations (i.e., pulsation) that may occur during this operation.

[0090] The above-mentioned twin screw pump 5A can be driven with high energy efficiency, for example, by using a motor to provide power to compensate for mechanical losses such as sliding friction resistance in the mechanism and piping pressure loss. As shown in Fig. 9, the twin screw pump 5A rotates a screw compressor 51A and a screw expander 52A connected in parallel (parallel).

[0091] The connection between the units 51A, 52A in the double screw pump 5A is not limited to the example shown in Figure 9, as long as it allows parallel operation. For example, a series connection may be used. For example, a reducer may be provided between the rotating shafts of the units 51A, 52A. Alternatively, the units 51A, 52A may be controlled to any desired rotation speed and phase using an inverter, or a pressure reducing valve or a flow rate adjusting valve may be used to control the units 51A, 52A so that a constant pressure difference can be stably maintained between the circulating water channel system 13 side of the cooling water Wa and the flow path section 3 side of the water treatment device 15.

[0092] 3-3. Intermittent control The water treatment device 15 of this embodiment uses an ON / OFF intermittent pulse to control, for example, the supply of high-frequency power to the electromagnetic field converter 4. By periodically stopping the supply of high-frequency power through this intermittent control, it is possible to suppress the proliferation of light water molecules that are excited by microwave heating and that may exist in a small proportion among the majority of light water molecules, thereby improving the selective transmittance of heavy water molecules.

[0093] For example, the heating time Ton during which the intermittent pulse is ON is set to be longer than 1 millisecond. Also, the rest time Toff during which the intermittent pulse is OFF is set to be 0.1 to less than 1 millisecond. By operating the water treatment device 15 so as to supply high-frequency power at such intervals, it is easy to promote heating of heavy water molecules.

[0094] If high-frequency power is applied continuously, it is conceivable that among the majority (absolute majority) of light water molecules present in the cooling water Wa, a small number that initially synchronize with the AC electric field Ea by chance will gradually become synchronized due to repeated accidental thermal disturbances. In this case, the synchronous rotation (excitation) with the AC electric field Ea will multiply and eventually grow into a majority. As a result, even if selectivity was initially secured by triggering NMR resonance only on heavy water molecules, that selectivity will be lost.

[0095] This multiplication phenomenon can be avoided by intermittently controlling the supply of high-frequency power. By intermittently stopping the supply of high-frequency power, it is possible to prevent water molecules (light water molecules) other than heavy water molecules that are synchronized by NMR excitation from being synchronously heated by the AC electric field Ea. This intermittent control will be explained in more detail using Figure 10.

[0096] Fig. 10 is a graph illustrating the intermittent control in water treatment device 15. Fig. 10 shows, in time series, the signal waveform of the AC electric field Ea under intermittent control, a graph Ga showing the proportion of heavy water molecules rotating synchronously with the AC electric field Ea, i.e., the synchronization rate, and a graph Gb showing the synchronization rate of light water molecules.

[0097] For example, the rotational motion of the D nucleus excited by the NMR spectroscopy using an AC magnetic field Ba, which originates from the same radio frequency power as the AC electric field Ea in Figure 10, synchronizes the rotation of heavy water molecules through a relaxation phenomenon (see Figure 2). Therefore, the synchronization rate of heavy water molecules initially increases linearly, as shown in graph Ga, and is accelerated by heating with the AC electric field Ea. However, because of the damping load imposed by interactions such as hydrogen bonding with surrounding water molecules and physical adsorption to the inner walls of the pores, the synchronization rate of heavy water molecules eventually saturates even if the AC electric field Ea is continuously applied.

[0098] On the other hand, since light water molecules are a group with random rotational phases, only a small number of molecules are initially synchronized in rotational phase when accelerated by the AC electric field Ea, as shown in graph Gb in Fig. 10. However, if the AC electric field Ea is continuously applied, the group of light water molecules is gradually drawn into a synchronized phase as the braking and acceleration described above are repeated. In this way, the number of synchronized light water molecules increases exponentially, and eventually, as in the case of heavy water molecules described above, acceleration (heating) and braking (loss) become balanced, and the synchronization rate saturates.

[0099] As shown in the graphs Ga and Gb in Figure 10, the synchronization rate of heavy water molecules is first increased by NMR relaxation. Therefore, although the ratio Ra:Rb (selective heating of heavy water molecules) of the synchronization rate of heavy water molecules to that of light water molecules is initially significantly higher than Ra>Rb, it is feared that it will eventually approach 1:1 and the selectivity will disappear.

[0100] Therefore, the water treatment device 15 of this embodiment performs the above-mentioned intermittent control to stop the generation of the AC electric field Ea every pause time Toff. During such pause time Toff, the acceleration (heating) of both molecules is stopped, and only braking (loss) occurs, resulting in an exponential decrease. When intermittent modulation is performed, in which the synchronization rate of the graph Gb etc. decreases appropriately over the lapse of the pause time Toff, the AC electric field Ea is applied again, and then the pause is resumed, the synchronization rate of both molecules fluctuates, for example, as shown in Figure 10. In such intermittent modulation, for example, by maximizing the ratio of the synchronization rates of both molecules, Ra:Rb, it is possible to precisely achieve selective heating of heavy water molecules.

[0101] For example, in the water treatment device 15 of Fig. 4, the power supply unit 6 intermittently supplies high-frequency power to the electromagnetic field converter 4 by intermittent pulse control of the heating time Ton and the rest time Toff. This makes it easy to achieve the intermittent control of the AC electric field Ea described above.

[0102] The heating time Ton is set so that it is equal to or shorter than the time required for the synchronization rate of light water molecules to transition from increasing to saturated, as shown in graph Gb in Fig. 10. This actual time depends on the strength of the AC electric field Ea, and can be determined experimentally using an actual system.

[0103] The lower limit of the rest time Toff can be estimated from the dielectric loss characteristics of water, for example. This estimation focuses on the correspondence between the sharpness of the resonance in the frequency distribution, i.e., the Q value (expressed as the ratio of the half-width at half maximum Δω to the resonant frequency ωo), which is common to resonant systems of various physical phenomena, and the ratio between the energy stored in the system and the energy lost per vibration period.

[0104] Specifically, first, from the frequency distribution of dielectric loss (see Figure 3), the Q value of free water is about "1 / 2 (up to 5GHz / 10GHz)", and the Q value of bound water is estimated to be a similar value. From this, if there are about three oscillation periods (for example, 0.014 microseconds at 70MHz) for the resonant frequency of bound water, then the Q value of "(1 / 2)" 3 It can be seen that the loss is sufficiently attenuated to about 1 / 10. In other words, it can be seen that this system is a forced vibration system in which the loss and heating are nearly equal. Therefore, it can be estimated that setting the rest time Toff to several to ten or more cycles (for example, approximately 0.04 microseconds or more at 70 MHz) is sufficient.

[0105] In the water treatment device 5 of this embodiment, the AC magnetic field Ba does not have to be intermittently controlled. For example, the water treatment device 15 of this embodiment may control the AC electric field Ea intermittently while controlling the AC magnetic field Ba continuously. For example, the supply of high-frequency power to an electric field generator such as a pair of opposing electrodes 42 may be controlled by switching.

[0106] 4. Summary As described above, the water treatment device 15 of this embodiment reduces the concentration of heavy water contained in cooling water Wa as the water to be treated. The water treatment device 15 includes a flow path 3, a superconducting magnet 2 as an example of a first magnetic field generator, an electromagnetic field converter 4 as an example of a second magnetic field generator and an electric field generator, and an electric field generator. The flow path 3 includes a flow path 3a through which the cooling water Wa flows and a filtration membrane 31 as an example of a filtration material that filters the cooling water Wa so as to discharge a portion of the cooling water Wa from the flow path 3a. The first magnetic field generator generates a static magnetic field Bb in the flow path 3. The second magnetic field generator generates an AC magnetic field Ba in the flow path 3, having a resonant frequency at which deuterium undergoes nuclear magnetic resonance in the static magnetic field Bb. The electric field generator generates an AC electric field Ea in the flow path 3, having the resonant frequency. The filtration material in the flow path 3 has pores 30 having a size that allows water molecules to rotate in response to the AC electric field Ea.

[0107] The water treatment device 15 described above can perform water treatment using various electromagnetic fields Ea, Ba, and Bb to utilize two types of resonance phenomena, NMR and molecular rotation, for deuterium in water to be treated, such as cooling water Wa. In this way, the water treatment device 15 can efficiently perform water treatment to reduce the concentration of heavy water contained in the water to be treated.

[0108] For example, in the water treatment device 15 of this embodiment, when light water and heavy water in the cooling water Wa pass through the pores 30 of the filtration membrane 31, adsorption and desorption are repeated on the inner walls of the pores 30, and only the deuterium in the heavy water molecules is excited by nuclear magnetic resonance. Due to this T1 relaxation phenomenon, only the thermally rotating heavy water molecules accelerate and decelerate in synchronization with the AC electric field Ea. The resulting heating action promotes desorption, and only the heavy water molecules pass through the pores in a short time. As a result, the filtration efficiency of heavy water can be increased.

[0109] In the water treatment device 15 of this embodiment, the strength of the static magnetic field Bb, the size of the pore 03, the material of the filtration material, and the temperature of the water to be treated are set so that the resonant frequency is within the range of the full width at half maximum 2Δω in the distribution of the rotational frequencies of water molecules in the pore 30.

[0110] This allows the nuclear magnetic resonance of deuterium constituting heavy water and the vibrational resonance of the dipole rotation of heavy water molecules caused by the AC electric field Ea to occur synchronously and simultaneously due to the AC magnetic field Ba generated within the pores 30 of the filtration membrane 31 by, for example, single-frequency radio frequency power. One example of such a setting method is to adjust the strength of the static magnetic field Bb based on the material and pore size of the filtration material used and the expected water temperature, since the NMR resonance frequency is proportional to the strength of the static magnetic field Bb and the proportionality coefficient is known as the nuclear magnetic moment of deuterium.

[0111] In this embodiment, a pair of opposing electrodes 42, which is an example of an electric field generator, is a plurality of electrodes that face each other across the flow path 3 in a direction that intersects with the magnetic flux direction of the static magnetic field Bb. This makes it easier to apply dielectric heating by the AC electric field Ea to heavy water molecules that have reached molecular rotation due to the relaxation phenomenon from NMR excitation. The direction of the AC electric field Ea does not need to be strictly perpendicular to the magnetic flux direction, and may be at an intersecting angle within a range that provides the above effect.

[0112] In this embodiment, the second magnetic field generating unit may be at least one coil arranged at a position different from the counter electrode 42 around the flow path unit 3. This allows an AC magnetic field Ba to be generated in the flow path unit 3 together with the AC electric field Ea, thereby enabling selective excitation of heavy water by NMR.

[0113] In this embodiment, at least one coil serving as the second magnetic field generating unit is a pair of saddle-shaped coils 41, which are an example of a plurality of coils each having a saddle shape and facing each other across the flow path unit 3. This makes it easy to generate an AC magnetic field Ba in the flow path unit 3 so as to intersect with the AC electric field Ea.

[0114] In this embodiment, the capacitor formed by the plurality of opposing electrodes 42 and the coil are electrically connected to each other as a resonant circuit 40 that resonates at a resonant frequency. This allows a synchronized AC magnetic field Ba and AC electric field Ea of the same frequency to be simultaneously generated in the flow path section 3 with a simple configuration.

[0115] In this embodiment, the first magnetic field generating unit is at least one superconducting magnet 2 having a hollow shape. The flow path unit 3 is arranged inside the superconducting magnet 2. The electromagnetic field converter 4 including the capacitor and the coil is arranged between the flow path unit 3 and the superconducting magnet 2. This allows the water treatment of this embodiment to be performed sequentially on the water to be treated that passes through the hollow shape of the superconducting magnet 2, making it easy to achieve efficient water treatment.

[0116] In this embodiment, the at least one superconducting magnet 2 may be a plurality of superconducting magnets 2 each having a hollow shape. A flow path section 3, a capacitor, and a coil may be arranged inside each superconducting magnet 2. The resonant circuits 40 corresponding to the capacitors and coils in each superconducting magnet 2 may be connected to each other as a ladder circuit (FIG. 8). This makes it easier to ensure a large water treatment throughput and allows the power supply system to be shared.

[0117] In this embodiment, the water treatment device 15 further includes a control pump 5. The control pump 5 is inserted between the flow path section 3 and a circulating water channel system 13, which is an example of an external water channel system that supplies the water to be treated as cooling water Wa to the heat source 12, and adjusts the pressure of water flowing from the water channel system into the flow path section 3 and the pressure of water flowing from the flow path section 3 to the water channel system. This makes it possible to adjust the water pressure in the water treatment device 15 while maintaining the operating pressure of the circulating water channel system 13, for example, in the cooling system 10 of the nuclear facility 1, thereby enabling efficient water treatment. Note that the control pump 5 may be an external component of the water treatment device 15.

[0118] In this embodiment, the control pump may be a plurality of screw pumps 5A connected in parallel, which can suppress pressure fluctuations such as pulsation that may occur when pressurizing and depressurizing the water in parallel in, for example, the water treatment device 15.

[0119] In this embodiment, the water treatment device 15 further includes a power supply unit 6. The power supply unit 6 supplies AC power, such as high-frequency power, to the electric field generator so as to intermittently generate the AC electric field Ea. This prevents the AC electric field Ea from accidentally acting on light water molecules, thereby increasing the heating of the light water molecules, and improves the selective filtration rate of heavy water molecules.

[0120] In this embodiment, the flow path unit 3 is connected to a waterway system so as to divert cooling water Wa from a circulating waterway system 13, which is an external waterway system through which water to be treated circulates, via, for example, a control pump 5, and return the diverted cooling water Wa to the waterway system via the flow path 3a. Such a bypass path makes it easier to realize water treatment for reducing the heavy water concentration in a large flow rate of cooling water Wa in a cooling system 10 of a nuclear facility 1, such as a nuclear power plant in operation.

[0121] In this embodiment, the flow path section 3 includes a first flow path 3a through which the water to be treated flows, and a second flow path 3b through which downstream water Wb, an example of external water different from the water to be treated, flows. The first flow path 3a and the second flow path 3b are adjacent to each other via a filtering material such as a filtration membrane 31. This allows heavy water to be filtered from the cooling water Wa flowing through the first flow path 3a and discharged into the downstream water of the second flow path 3b, thereby efficiently reducing the concentration of heavy water in the water to be treated. Note that the flow path section 3 does not necessarily have to include the second flow path 3b; for example, the second flow path 3b may be formed outside the flow path section 3, with the filtering material as a boundary.

[0122] The water treatment method of this embodiment is a method for performing water treatment to reduce the concentration of heavy water contained in water to be treated. This method includes, for example, operating a water treatment device 15, flowing the water to be treated through a flow path unit 3 including a flow path and a filtration material, generating a static magnetic field Bb in the flow path unit 3, generating an AC magnetic field Ba in the flow path unit 3 having a resonant frequency at which deuterium undergoes nuclear magnetic resonance in the static magnetic field Bb, generating an AC electric field Ea in the flow path unit 3 having the resonant frequency, and rotating water molecules in accordance with the AC electric field Ea in pores 30 provided in the filtration material in the flow path unit 3, thereby filtering the water so as to discharge a portion of the water containing heavy water through the filtration material. This allows for efficient water treatment to reduce the concentration of heavy water contained in the water to be treated.

[0123] (Embodiment 2) In the above-described first embodiment, a configuration example of the water treatment device 15 using the filtration membrane 31, which is an example of a filtration material, was described, but the filtration material is not particularly limited to this, and various configurations can be adopted. In the second embodiment, a configuration example of the water treatment device in which the surface area of ​​the filtration material is increased will be described.

[0124] Fig. 11 shows a configuration example of a water treatment device 15A according to embodiment 2. Fig. 12 shows a schematic cross-sectional view taken along line AA corresponding to the central cross-section of the water treatment device 15A in Fig. 11. In each drawing, the configuration of the water treatment device 15A according to this embodiment other than the flow path section 3A and the superconducting magnet 2 is omitted.

[0125] A water treatment device 15A of this embodiment has the same configuration as the water treatment device 15 of Embodiment 1, but instead of the flow path portion 3 using the filtration membrane 31, it includes a flow path portion 3A of a shell-and-tube type equipped with a filtration material, as shown in Figures 11 and 12. The flow path portion 3A of this embodiment includes, for example, a horizontal cylindrical shell portion 32 and a tube portion 33 as an example of a filtration material.

[0126] According to the water treatment device 15A of this embodiment, the selective permeability of heavy water molecules can be improved by increasing the surface area of ​​the filtration material, for example, by using the tube portion 33 of the flow path portion 3A, rather than increasing the thickness of the filtration material. This reduces pressure loss in the filtration material and allows the flow path portion 3A to be made smaller.

[0127] In the water treatment device 15 of this embodiment, the superconducting coil 2 is disposed outside the shell portion 32 of the flow path portion 3A. The shell portion 32 is a member that constitutes a container for the tube portion 33. For example, the material of the shell portion 32 is the non-magnetic, insulating, and non-dielectric material described above. The tube portion 33 is formed by filtration material in the form of hollow fibers (long flexible thin tubes). A structure similar to that of a filter in a water purifier can be employed, in which a large number of tube portions 33 are housed in a longitudinal cylindrical space in which a magnetic field is generated inside the shell portion 32.

[0128] In the flow path portion 3A of this embodiment, the inside of the tube portion 33 forms a flow path 3a for the cooling water Wa. In the shell portion 32, the outside of the tube portion 33 forms a flow path 3b for the external water Wb. A piping structure is provided so that high-pressure cooling water Wa is supplied to the hollow inside of the tube portion 33 and low-pressure external water Wb is supplied to the outside, and both types of water circulate.

[0129] In the flow path section 3A of this embodiment, the cylindrical shape of the shell portion 32 is suitable for withstanding the pressure difference between the cooling water Wa and the external water Wb. The shell portion 32 can be minimized in thickness and weight to meet the required pressure resistance. Furthermore, the flexible thin tube portion 33 can be accommodated in large numbers in a longitudinal cylindrical space where a static magnetic field is generated, for example, by a solenoid-shaped superconducting magnet 2, thereby ensuring a wide area of ​​the partition interface between the cooling water Wa and the external water Wb. Thus, the water treatment device 15A of this embodiment can improve the selective permeability of heavy water molecules.

[0130] The above-described configuration example is a basic structure in which the cooling water Wa and the external water Wb flow in countercurrent directions in the shell-and-tube type flow path section 3A, and various modifications are possible. These modifications will be described with reference to FIG.

[0131] In the flow path section 3A of the present embodiment, the tube section 33 through which the cooling water Wa flows may be folded back within the shell section 32 to form multiple passes, as shown in Fig. 13, for example. For example, the tube section 33 may be formed into multiple passes, such as three passes or five passes, each time it travels back and forth within the shell section 32, with the portion spanning the longitudinal direction of the shell section 32 being one pass. By forming the tube section 33 into multiple passes, the time that the cooling water Wa remains in the water treatment device 15A for heavy water filtration can be extended, and the selective permeability of heavy water molecules can be improved.

[0132] Furthermore, in the flow path section 3A of this embodiment, a baffle 34 may be provided inside the shell section 32, as shown in FIG. 13, for example. The baffle 34 is configured, for example, in the shape of a plate through which the tube section 33 is inserted, and agitates the water flow of the external water Wb. This allows the cooling water Wa and the external water Wb to flow in a state similar to a completely countercurrent flow. In other words, the concentration difference between the heavy water concentration in the cooling water Wa and the heavy water concentration in the external water Wb is made uniform throughout the shell section 32, thereby improving the selective permeability of heavy water molecules.

[0133] As described above, in the water treatment device 15A of the second embodiment, the tube portion 33, which is an example of a filtration material, includes a plurality of hollow fibers. The flow path portion 3 has a piping structure in which the water to be treated flows through the interior of the plurality of hollow fibers as a first flow path 3a, and outside water flows through the exterior of the hollow fibers in the flow path portion 3 as a second flow path 3b. This ensures a large area for the partition interface for selectively filtering heavy water in the water treatment device 15A.

[0134] (Other embodiments) In the above-described first and second embodiments, examples of the configuration of the water treatment device 15 are described, each using a filtering material having a structure such as the filtration membrane 31 or the tube portion 33. A modified example of the material of the filtering material of the water treatment device 15 will be described with reference to FIG.

[0135] 14 is a graph illustrating a modified example of the filtration material of the water treatment device 15. In the water treatment device 15 of this embodiment, from the viewpoint of improving the property of facilitating selective adsorption / desorption of light water and heavy water, respectively, and facilitating control, a porous material that shows a large increase or decrease in the amount of adsorption within a specific narrow relative pressure range may be used as the filtration material. Specifically, mesoporous silica having cylindrical pores is one example of a candidate for the filtration material of this embodiment.

[0136] The adsorption of liquids into porous materials depends not only on the interaction between the material surface and the liquid, but also on the size, structure, and regularity of the pores. Adsorption characteristics are generally evaluated using an adsorption isotherm, which shows the relationship between the amount of adsorption and pressure under isothermal conditions. Figure 14 shows examples of adsorption isotherms classified by IUPAC that have hysteresis.

[0137] In Figure 14, silica gel and mesoporous silica with mesopores are classified as Type IV and Type V (left side of the figure), and exhibit hysteresis, which indicates an increase and decrease in the amount of adsorption within a certain range of relative pressure. In particular, among mesoporous silica with uniform pore size and regular structure, cylindrical pores are classified as Type H1 (right side of the figure), and exhibit significant hysteresis, which indicates an increase and decrease in the amount of adsorption within a specific narrow range of relative pressure during the adsorption / desorption process.

[0138] The increase / decrease in the amount of adsorption, such as the phase change described above, is caused by capillary condensation / evaporation inside the mesopores. By utilizing this property, it is possible to improve the selective adsorption / desorption characteristics by adjusting the pressure so that light water molecules are adsorbed and excited heavy water molecules are desorbed. Furthermore, by considering the pressure adjustment according to such adsorption characteristics, it is easy to identify a control method that enables stable operation of the water treatment device 15 of this embodiment.

[0139] As described above, in the water treatment device 15 of this embodiment, the filtration material includes a porous material that exhibits a greater increase and decrease in adsorption amount than types IV and V in a narrower relative pressure range than types IV and V in the IUPAC classification in a predetermined adsorption isotherm. For example, an H1-type porous material is used for the filtration material. This allows for the use of a porous material that exhibits a greater increase and decrease in adsorption amount within a specific narrow relative pressure range, and by adjusting the pressure to an adsorption state for light water molecules and a desorption state for excited heavy water molecules, selective adsorption / desorption characteristics can be improved. Furthermore, a control method that enables stable operation can be identified.

[0140] In addition, in each of the above embodiments, the electromagnetic field converter 4 has been described as an example of the electric field generator and the second magnetic field generator in the water treatment device 15, but the configuration of the electric field generator and the second magnetic field generator is not particularly limited to this. For example, the second magnetic field generator is not particularly limited to a pair of saddle-shaped coils 41, and may be coils of various shapes. The number of coils in the second magnetic field generator is not particularly limited to two, and may be one, three, or more.

[0141] Furthermore, in this embodiment, the resonant circuit 40 of the electromagnetic field converter 4 is not particularly limited to the above-mentioned examples (FIGS. 7 and 8), and may include, for example, another inductor and capacitor in addition to or instead of the coil 41 (second magnetic field generator) and the counter electrode 42 (electric field generator). For example, the resonant circuit 40 may be provided with a circuit element whose inductance and capacitance are variable. The resonant circuit 40 does not particularly need to be a multi-stage ladder circuit, and may be a single-stage ladder circuit. Furthermore, separate resonant circuits may be provided for the coil 41 (second magnetic field generator) and the counter electrode 42 (electric field generator).

[0142] Furthermore, in this embodiment, the second magnetic field generator and the electric field generator do not necessarily have to be integrated into the electromagnetic field converter 4, and may be configured as separate bodies as appropriate. Furthermore, in this embodiment, the structures of the electric field generator and the second magnetic field generator can be selected appropriately depending on the strength required for the alternating electromagnetic fields Ea and Ba. For example, an antenna structure that irradiates electromagnetic waves may be used if such requirements are met.

[0143] In addition, in each of the above embodiments, an application example of the water treatment device 15 has been described in which the cooling water Wa is treated in the nuclear facility 1. In this embodiment, the application example of the water treatment device 15 is not necessarily limited to the nuclear facility 1, and the water treatment device 15 may be applied to, for example, the production of deuterium-reduced water. The water treatment device 15 of this embodiment can be applied to water in which the concentration of heavy water is to be reduced in various applications such as biology, chemistry, and medicine.

[0144] (Summary of aspects) Various aspects of the present invention are described below.

[0145] A first aspect of the present invention is a water treatment device for reducing the concentration of heavy water contained in water to be treated, comprising: a flow path section including a flow path through which the water to be treated flows and a filtration material that filters the water so as to discharge a portion of the water from the flow path, a first magnetic field generator that generates a static magnetic field in the flow path section, a second magnetic field generator that generates an AC magnetic field in the flow path section having a resonant frequency at which deuterium undergoes nuclear magnetic resonance in the static magnetic field, and an electric field generator that generates an AC electric field in the flow path section having the resonant frequency. The filtration material in the flow path section has pores that are sized to allow water molecules to rotate in response to the AC electric field.

[0146] In a second aspect, in the water treatment device described in the first aspect, the strength of the static magnetic field, the size of the pore, the material of the filtration material, and the temperature of the water to be treated are set so that the resonant frequency is within the full width at half maximum range of the distribution of the rotational frequencies of the water molecules in the pore.

[0147] In a third aspect, in the water treatment device described in the first or second aspect, the electric field generating unit is a plurality of electrodes facing each other via the flow path unit in a direction intersecting the magnetic flux direction of the static magnetic field.

[0148] In a fourth aspect, in the water treatment device according to the third aspect, the second magnetic field generating unit is at least one coil arranged at a position different from the plurality of electrodes around the flow path unit.

[0149] In a fifth aspect, in the water treatment device according to the fourth aspect, the at least one coil is a plurality of coils that face each other across the flow path portion and each have a saddle shape.

[0150] In a sixth aspect, in the water treatment device according to the fourth aspect, a capacitor formed by the plurality of electrodes and the coil are electrically connected to each other as a resonant circuit that resonates at the resonant frequency.

[0151] In a seventh aspect, in the water treatment device according to the sixth aspect, the first magnetic field generating unit is at least one superconducting magnet having a hollow shape, the flow path unit is disposed inside the superconducting magnet, and the capacitor and the coil are disposed between the flow path unit and the superconducting magnet. The water treatment device according to claim 6.

[0152] In an eighth aspect, in the water treatment device according to the seventh aspect, the at least one superconducting magnet is a plurality of superconducting magnets each having a hollow shape. The flow path portion, the capacitor, and the coil are arranged inside each superconducting magnet. The resonant circuits corresponding to the capacitor and the coil in each superconducting magnet are connected to each other as a ladder circuit.

[0153] In a ninth aspect, the water treatment device according to any one of the first to eighth aspects further comprises a control pump inserted between an external water channel system that supplies the water to be treated to a heat source as cooling water and the flow path section, and that adjusts the water pressure flowing from the water channel system into the flow path section and the water pressure flowing from the flow path section to the water channel system.

[0154] A tenth aspect of the present invention is the water treatment device according to the ninth aspect, wherein the control pump is a plurality of screw pumps connected in parallel.

[0155] In an eleventh aspect, the water treatment device according to any one of the first to tenth aspects further includes a power supply unit that supplies AC power to the electric field generation unit so as to generate the AC electric field intermittently.

[0156] In a twelfth aspect, in a water treatment device described in any one of the first to eleventh aspects, the flow path section is connected to the water channel system so as to divert the water from an external water channel system through which the water to be treated circulates and return the diverted water to the water channel system via the flow path.

[0157] In a thirteenth aspect, in the water treatment device according to any one of the first to twelfth aspects, the flow path unit further comprises a first flow path through which the water to be treated flows and a second flow path through which external water different from the water to be treated flows, and the first flow path and the second flow path are adjacent to each other via the filtration material.

[0158] In a fourteenth aspect, in the water treatment device according to the thirteenth aspect, the filtration material includes a plurality of hollow fibers. The flow path section has a piping structure in which the water to be treated flows through the interiors of the plurality of hollow fibers as the first flow path, and the outside water flows through the exterior of the hollow fibers in the flow path section as the second flow path.

[0159] In a fifteenth aspect, in the water treatment device according to any one of the first to fourteenth aspects, the filtration material includes a porous material that exhibits a greater increase and decrease in adsorption amount than types IV and V in the IUPAC classification within a narrower relative pressure range in a predetermined adsorption isotherm.

[0160] A sixteenth aspect is a water treatment method for reducing the concentration of heavy water contained in water to be treated, comprising: flowing the water to be treated through a flow path section having a flow path and a filtration material; generating a static magnetic field in the flow path section; generating an alternating current magnetic field in the flow path section having a resonant frequency at which deuterium undergoes nuclear magnetic resonance in the static magnetic field; generating an alternating current electric field in the flow path section having the resonant frequency; and rotating water molecules in pores provided in the filtration material in the flow path section in accordance with the alternating current electric field, thereby filtering the water so as to discharge a portion of the water containing the heavy water in the filtration material. [Explanation of symbols]

[0161] 1. Nuclear facilities 12 Heat Source 13 Circulation waterway system 15 Water Treatment Equipment 2. Superconducting magnet 3,3A Flow path section 3a,3b flow path 30 pores 31 Filtration membrane 33 Tube section 4 Electromagnetic field converter 40 Resonant circuit 41 Saddle coil 42 Counter electrode 5 Control pump 5A screw pump 6 Power supply section

Claims

1. A water treatment device that reduces the concentration of heavy water contained in water to be treated, a flow path section including a flow path through which the water to be treated flows and a filter material having pores so as to discharge a portion of the water from the flow path; a first magnetic field generating unit that generates a static magnetic field in the flow path; a second magnetic field generating unit that generates, in the flow channel, an alternating current magnetic field having a resonance frequency at which deuterium undergoes nuclear magnetic resonance in the static magnetic field; an electric field generating unit that generates an AC electric field having the resonance frequency in the flow path section, The pores of the filtering material in the flow path portion have a size such that water molecules of bound water bound in the pores when the water flows in from the flow path can rotate by dipole rotation in response to the AC electric field. Water treatment equipment.

2. The strength of the static magnetic field, the size of the pores, the material of the filtering material, and the temperature of the water to be treated are set so that the resonant frequency is within a range of the full width at half maximum of the distribution of the rotational frequencies of the water molecules in the pores. The water treatment device according to claim 1 .

3. The electric field generating unit is a plurality of electrodes that face each other across the flow path in a direction that intersects with the magnetic flux direction of the static magnetic field. The water treatment device according to claim 1 or 2.

4. The second magnetic field generating unit is at least one coil arranged at a position different from the plurality of electrodes around the flow path unit. The water treatment device according to claim 3 .

5. The at least one coil is a plurality of coils that face each other across the flow path and each have a saddle shape. The water treatment device according to claim 4.

6. The capacitor formed by the plurality of electrodes and the coil are electrically connected to each other as a resonant circuit that resonates at the resonant frequency. The water treatment device according to claim 4 .

7. the first magnetic field generating unit is at least one superconducting magnet having a hollow shape, the flow path portion is disposed inside the superconducting magnet, The capacitor and the coil are disposed between the flow path and the superconducting magnet. The water treatment device according to claim 6.

8. the at least one superconducting magnet is a plurality of superconducting magnets each having a hollow shape, the flow path portion, the capacitor, and the coil are disposed inside each superconducting magnet; The resonant circuits corresponding to the capacitors and the coils in each of the superconducting magnets are connected to each other as a ladder circuit. The water treatment device according to claim 7.

9. The system further includes a control pump inserted between an external water channel system that supplies the water to be treated as cooling water to a heat source and the flow path section, and that adjusts the water pressure flowing from the water channel system into the flow path section and the water pressure flowing from the flow path section into the water channel system. The water treatment device according to claim 1 or 2.

10. The control pump is a plurality of screw pumps connected in parallel. The water treatment device according to claim 9.

11. The electric field generating unit may further include a power supply unit that supplies AC power to the electric field generating unit so as to intermittently generate the AC electric field. The water treatment device according to claim 1 or 2.

12. The flow path section is connected to the waterway system so as to divert the water from an external waterway system in which the water to be treated circulates and return the diverted water to the waterway system via the flow path. The water treatment device according to claim 1 or 2.

13. the flow path unit further includes a first flow path through which the water to be treated flows and a second flow path through which external water different from the water to be treated flows; The first flow path and the second flow path are adjacent to each other via the filter material. The water treatment device according to claim 1 or 2.

14. The filtration material includes a plurality of hollow fibers, The flow path section is a piping structure in which the water to be treated flows through the interiors of the plurality of hollow fibers as the first flow path, and the outside water flows through the exteriors of the hollow fibers in the flow path section as the second flow path. The water treatment device of claim 13.

15. The filtration medium includes a porous material that exhibits a greater increase and decrease in adsorption amount than Types IV and V in the IUPAC classification within a narrower relative pressure range in a predetermined adsorption isotherm. The water treatment device according to claim 1 or 2.

16. A water treatment method for reducing the concentration of heavy water contained in water to be treated, comprising: A flow path portion includes a flow path and a filter material, and the water to be treated is caused to flow through the flow path; generating a static magnetic field in the flow path section; generating an AC magnetic field in the flow channel portion, the AC magnetic field having a resonance frequency that causes deuterium to undergo nuclear magnetic resonance in the static magnetic field; generating an AC electric field having the resonant frequency in the flow path portion; The method includes rotating the water molecules in response to the AC electric field in pores provided in the filtering material in the flow path portion, the pores having a size that allows the water molecules bound in the pores to rotate by dipole rotation in response to the AC electric field, and discharging a portion of the water containing the heavy water in the filtering material. Water treatment methods.

Images