JP2016212003A - Method and device for removing radioactive substances - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for removing radioactive substances capable of extensively attracting contaminated water containing radioactive substances and thus efficiently removing the contaminated water from soil.SOLUTION: Provided is a method for removing radioactive substances which removes radioactive substances from soil 2 permeated by contaminated water containing the radioactive substances, comprising the steps of: burying a permeable trench member 3 in the soil 2; storing an electrolyte solution 4 in the trench member 3; immersing a cathode 5 in the electrolyte solution 4; inserting an anode 6 in the soil 2 away from the trench member 3; applying a voltage between the anode 6 and the cathode 5 to generate an electro-osmotic phenomenon by which the cathode 5 attracts contaminated water containing radioactive substances in the soil 2 between the anode 6 and the cathode 5, so that the contaminated water flows in the electrolyte solution 4 through the trench member 3; and draining the electrolyte solution 4 containing the contaminated water from the trench member 3 by drainage means 8 to complete the removal of the radioactive substances from the soil 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radioactive substance removing method and a radioactive substance removing apparatus, and more particularly to a radioactive substance removing method and a radioactive substance removing apparatus capable of collecting and removing contaminated water containing radioactive substances from soil contaminated by radioactive substances. .

  A radioactive substance is a radioactive isotope of a metal element such as an alkali metal, but it does not exist as a single element in soil moisture, and is a chemical compound called a salt that is ionically bonded to elements such as sulfuric acid in the atmosphere or soil. It exists in the form of a bond. In general, soil contains moisture in fine silty and clay constituting the components of the soil. In particular, in wet soil due to the influence of rainfall and groundwater, moisture is adsorbed by silt and clayey fine particles having a particle diameter of 0.074 mm or less, which occupies at least 10% of ordinary soil components, and the particle diameter exceeds 0.075 mm. Sand or gravel particles made of quartz or the like exist as interstitial water between particles.

  In the interstitial water of soil and silt, which is a soil component, and sand and gravel particles, which are coarse particles, the radioactive isotopes in the soil ionically bound as salts are ionized from the salt and become water as ions. It is often dissolved in water and constitutes contaminated water in the soil. In this way, for soil contaminated with radioactive substances, by applying an electrical coulomb force to the contaminated water in the soil, the contaminated water is forcibly moved by the electroosmosis phenomenon to a certain location. Can collect water.

  As an invention to extract ionized pollutants in soil by utilizing electroosmosis phenomenon, the cathode and anode are inserted into the contaminated soil at a distance, and voltage is applied to them to extract ionized radioactive material. An apparatus is known that collects moisture (contaminated water) contained in a cathode (see, for example, Patent Document 1). In this device, it has a cylindrically formed cathode, a plurality of through holes are formed on the side surface of the cathode, contaminated water drawn to the cathode by the electroosmosis phenomenon is taken into the cathode from the through hole, The contaminated water taken into the cathode is pumped up by a vacuum pump.

JP 2003-31256 A

  By the way, in the above-described conventional apparatus, a cylindrical cathode is inserted into the soil, and the contaminated water in the soil in the vicinity centering on the cathode is attracted to the cathode by the electroosmosis phenomenon and removed. For this reason, although contaminated water within a specified radius centered on a cylindrical cathode can be removed efficiently, it is necessary to insert a large number of cathodes into the soil to accurately remove a wider range of contaminated water. There is room for improvement in terms of efficiency.

  The present invention was devised in view of such problems, and provides a radioactive substance removal method and a radioactive substance removal apparatus capable of efficiently removing contaminated water containing radioactive substances from soil over a wide range. The purpose is to provide.

  According to the present invention, a radioactive substance removal method for removing radioactive substances from soil contaminated with radioactive substances, burying a trench member having water permeability in the soil, and storing an electrolyte solution in the trench member, A trench is immersed in the electrolyte solution, an anode is inserted into the soil at a distance from the trench member, and a contaminated water containing the radioactive substance is applied to the trench member by applying a voltage between the anode and the cathode. A radioactive substance removing method is provided, wherein the radioactive substance is removed from the soil by discharging the electrolyte solution collected therein and mixed with the contaminated water from the trench member.

  Further, according to the present invention, there is provided a radioactive substance removing device that removes a radioactive substance from soil contaminated with a radioactive substance, the trench member having water permeability and embedded in the soil, and stored in the trench member. An electrolyte solution, a cathode immersed in the electrolyte solution, an anode inserted into the soil at a distance from the trench member, a power supply means for applying a voltage between the anode and the cathode, Drainage means capable of discharging the liquid in the trench member, and collecting contaminated water containing the radioactive substance in the trench member by applying a voltage between the anode and the cathode; A radioactive substance removing device is provided, wherein the radioactive substance is removed from the soil by discharging the electrolyte solution mixed with the from the trench member.

  The trench member may be embedded so as to protrude from the surface of the soil while being open at the top. In addition, a plurality of the trench members may be disposed substantially parallel to the soil at intervals, and the anode may be disposed between the trench members. A plurality of the anodes may be arranged substantially in parallel along the longitudinal direction of the trench member.

  The power supply means may be constituted by a solar power generation device, a wind power generation device, or another renewable energy power generation device.

  According to the radioactive substance removal method and the radioactive substance removal apparatus according to the present invention, by burying the trench member storing the electrolyte solution in the soil contaminated with the radioactive substance, and applying a voltage between the cathode and the anode, A radioactive substance can be accommodated in the trench member by electroosmosis. In particular, since the entire trench member can act as a cathode, contaminated water containing radioactive substances can be efficiently removed from a wide range of soil corresponding to the length and embedment depth of the trench member.

1 is an overall view of a radioactive substance removing device according to a first embodiment of the present invention. It is explanatory drawing of the trench member shown in FIG. 1, (a) is a perspective view of a trench member, (b) is a cross-sectional view of a trench member. It is the schematic of the drainage means shown to Fig.2 (a). It is a general view of the radioactive substance removal apparatus which concerns on 2nd embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. .

As shown in FIG. 1, the radioactive substance removal device 1 according to the first embodiment of the present invention is
The radioactive material is removed from the soil 2 contaminated with the radioactive material, and has a water-permeable trench member 3 embedded in the soil 2, an electrolyte solution 4 stored in the trench member 3, and an electrolyte solution 4. A cathode 5 immersed in the soil, an anode 6 inserted into the soil 2 at a distance from the trench member 3, a power supply means 7 for applying a voltage between the anode 6 and the cathode 5, and a liquid in the trench member 3 Drainage means 8 capable of discharging the water.

  According to such a radioactive substance removing apparatus 1, by applying a voltage between the anode 6 and the cathode 5, the contaminated water containing the radioactive substance is recovered in the trench member 3 by the electroosmosis phenomenon, and the contaminated water is mixed with the electrolyte. By discharging the solution 4 from the trench member 3, the radioactive material can be removed from the soil 2.

  The soil 2 is, for example, farmland such as rice fields and fields, forest land such as mountain forests, residential land such as residential areas and industrial areas, public land such as roads and parks, and the like that has been infiltrated with contaminated water containing radioactive substances such as cesium and strontium. Etc. In the case where the soil is rice field, the trench member 3 is embedded in the roadway of the rice field. The soil 2 includes the underground of the reactor building and the surrounding land. Moreover, the soil 2 is not necessarily limited to the place where the soil is exposed, and may be a place where the trench member 3 can be embedded by penetrating or removing asphalt or concrete.

  Since this radioactive substance removal apparatus 1 removes radioactive substances as contaminated water together with the moisture in the soil 2, the soil 2 must be moist soil or soil that can retain water (for example, rice fields). preferable. Of course, when the soil 2 is dry, the soil 2 may be forcedly moistened by spraying or pouring water.

  As shown in FIGS. 1 and 2 (a), the trench member 3 is composed of, for example, a rectangular container having an open upper portion, and has a straight trench member 3a formed in a bowl shape and an end having a side wall on one side. The partial trench member 3b is connected via a liquid-tight seal. The trench member 3 may be an integrally molded product, or may be configured by combining two or four or more parts. The cross-sectional shape of the trench member 3 is not limited to the concave shape, and may be a semicircular shape. Moreover, the trench member 3 does not need to have a linear shape, and may be curved or bent.

  The trench member 3 has water permeability that is permeable to contaminated water. For example, unglazed porcelain having a very fine porosity, inorganic porous material (porous ceramic, porous glass, etc.), and porous performance. It is formed of a synthetic polymer material (polyethylene, polypropylene, etc.).

  When soil 2 in which contaminated water penetrates to a shallow depth of about 50 cm from the ground surface is used as the trench member 3, for example, one having a buried depth d = 100 cm or less and a thickness t = 5 cm or less is used. It is done. The length L of the trench member 3 is set according to the range of the soil 2 from which the contaminated water is removed, and the width W of the trench member 3 is immersed in the amount of the electrolyte solution 4 stored in the trench member 3 and the electrolyte solution 4. It is set according to the size of the cathode 5 to be applied.

  In the present embodiment, as shown in FIG. 1, a plurality of trench members 3 are arranged in parallel on the soil 2 with an interval X therebetween. The interval X between the trench members 3 is set according to the range of the soil 2 from which the contaminated water is removed and the strength of the voltage applied between the anode 6 and the cathode 5. The number of trench members 3 may be one or may be three or more.

  As shown in FIG. 2B, the trench member 3 is embedded in the soil 2 so that the upper part protrudes from the surface of the soil 2 (the ground surface 2a), and the upper part is opened to the atmosphere. With this configuration, it is possible to suppress the intrusion of rainwater or the like flowing on the ground surface 2a into the trench member 3, and to suppress the decrease in the concentration of the contaminated water drawn into the trench member 3 or the leakage of the collected contaminated water. it can.

  Note that a lid may be attached to the upper portion of the trench member 3 to suppress intrusion of rain, dust, or the like. Further, when the lid is attached, the trench member 3 may be completely embedded in the soil 2. In this case, since the trench member 3 does not exist on the ground surface 2a, it is possible not to obstruct traffic or to effectively use the ground surface.

  The trench member 3 stores an electrolyte solution 4 as shown in FIGS. As the electrolyte solution 4, a liquid having electrical conductivity such as an aqueous solution of acid, base or salt, an aqueous solution of ammonia or hydrogen peroxide, in addition to natural water having conductivity which is not pure water, is used.

  A cathode 5 is immersed in the electrolyte solution 4 in the trench member 3. The cathode 5 is composed of a metal pipe, a metal rod, or the like along the longitudinal direction of the trench member 3. For example, a metal pipe or a metal rod serving as the cathode 5 has a diameter of 1/3 or less of the width W (inner width) of the trench member 3. When a metal pipe is used for the cathode 5, the contact area with the electrolyte solution 4 is larger than that of the metal rod, so that the efficiency as the cathode 5 for attracting contaminated water can be increased.

  Note that a metal pipe or metal rod provided with fins or grooves on the outer peripheral surface or inner peripheral surface may be used as the cathode 5 to increase the contact area with the electrolyte solution 4. For example, a cathode terminal 5 a having an L-shaped cross section is attached to the cathode 5 by welding or the like, and a cathode wire 5 b is connected to the cathode terminal 5 a so that a negative voltage is applied to the cathode 5. ing.

  As shown in FIG. 1, the anode 6 is inserted into the soil 2 at a distance from the trench member 3. The anode 6 is made of a metal rod having a length substantially equal to or greater than or equal to the depth d of the trench member 3, and a plurality of anodes 6 are arranged in parallel with the trench member 3 at intervals. When the length of the anode 6 is made longer than the depth d of the trench member 3, the range in which the cron force of the electric lines of force operates according to the length L of the trench member 3 can be increased. It can be recovered efficiently.

  As shown in FIG. 1, when a pair of trench members 3 are arranged in parallel on the soil 2, the anode 6 is disposed at an intermediate position between the trench members 3. An anode wire 6b is connected to the anode 6 through an anode terminal 6a, and a positive voltage is applied to the anode 6. Note that the anode 6 protrudes from the ground surface 2 a in FIG. 1, but may be completely embedded in the soil 2.

  A voltage is applied to the cathode 5 and the anode 6 by the power supply means 7 shown in FIG. The power supply means 7 includes, for example, a power generation means 7a that generates electric power, an AC / DC converter 7b that converts alternating current into direct current, and a direct current that controls the direct current and voltage converted by the AC / DC converter 7b. A power supply device 7c, and a minus terminal box 7d and a plus terminal box 7e connected to the DC power supply device 7c are provided. The configuration of the power supply means 7 is not limited to the configuration shown in FIG. 1, and may be another configuration as long as an appropriate voltage can be applied between the cathode 5 and the anode 6.

  The power generation means 7a is preferably, for example, solar power generation, wind power generation, or other renewable energy power generation, but may be a storage battery or a prime mover. If the power generation means 7a generates DC power, the AC / DC converter 7b can be omitted. When renewable energy power generation is used as the power generation means 7a, power is constantly supplied to the radioactive substance removal device even in places where power infrastructure facilities are not provided or where it is difficult to supply fuel. be able to.

  The power supplied by the power generation means 7a is not limited to the supply to the cathode 5 and the anode 6, but requires the power of the suction pump 8b and the on-off valve 8c of the drainage means 8 (see FIG. 3). Can be supplied to all devices.

  The electric capacities (current and voltage) of the AC / DC converter 7b and the DC power supply device 7c are adjusted according to the number and length of the cathode 5 and the anode 6, and an appropriate voltage is applied to the cathode 5 and the anode 6. It is comprised so that it can apply. The minus terminal in the minus terminal box 7d is connected to the cathode 5 through the minus electric wire 5c, the minus power source line 5d, the cathode electric wire 5b, and the cathode terminal 5a. The plus terminal in the plus terminal box 7e is connected to the anode 6 via the plus wire 6c, the plus power supply line 6d, the anode wire 6b, and the anode terminal 6a.

  The power supply means 7 has one or more of a half-wave rectified waveform, a full-wave rectified waveform, a pulse waveform, and an AC waveform in addition to the function of generating direct current by the AC / DC converter 7b and the direct-current power supply device 7c. It may have a function of generating a waveform current. By applying these alternating voltages to the cathode 5 and the anode 6, the pulsation or impulse can be given to the soil 2 between the cathode 5 and the anode 6, and the contaminated water of the soil 2 can be easily collected. Can do.

  The electrolyte solution 4 mixed with the contaminated water in the trench member 3 is taken out by the drainage means 8 shown in FIGS. 2A and 3 and drained into the contaminated water tank 9. The drainage means 8 includes a drain pipe 8a that connects the trench member 3 and the contaminated water tank 9, and a suction pump 8b provided in the drain pipe 8a. One end of the drain pipe 8 a is located below the surface of the electrolyte solution 4 in the trench member 3, and the other end faces the contaminated water tank 9.

  The drain pipe 8a is provided with an on-off valve 8c and a check valve 8d as necessary. A so-called vacuum pump is used as the suction pump 8b. The contaminated water tank 9 is configured to prevent leakage of radioactive substances, and can contaminate the contaminated water with a material having a high radioactive shielding effect such as concrete or steel plate concrete. The configuration of the drainage means 8 is not limited to the illustrated configuration.

  As shown in FIG. 2A, the trench member 3 is connected with a water supply pipe 10a as the water supply means 10, so that a new electrolyte solution 4 is supplied into the trench member 3 through the water supply pipe 10a. It has become. Specifically, the electrolyte solution 4 mixed with contaminated water is drained from the trench member 3 by the drainage means 8, and a new electrolyte solution 4 corresponding to the amount of drainage is replenished in the trench member 3 by the water supply means 10. In addition, you may make it reuse the electrolyte solution which removed the radioactive substance from the electrolyte solution with which the contaminated water in the contaminated water tank 9 was mixed in the new electrolyte solution 4 to be replenished.

  When the radioactive substance removing device 1 described above is used to remove radioactive substances from the soil 2 as contaminated water, as shown in FIG. 1, trench members 3 having water permeability are embedded in the soil 2 in parallel at intervals. The electrolyte solution 4 is stored in the trench member 3, the cathode 5 is immersed in the electrolyte solution 4, and the anode 6 is inserted into the soil 2 between the trench members 3. Thereafter, the power supply means 7 is connected to the cathode 5 and the anode 6 by performing wiring work, and the drainage means 8 and the water supply means 10 are laid as shown in FIGS. 2 and 3 by performing piping work. A negative voltage is applied to each cathode 5 from a negative terminal box 7d, and a positive voltage is applied to each anode 6 from a positive terminal box 7e.

  After the installation of the radioactive substance removing device 1 is completed, a predetermined voltage is applied between the cathode 5 and the anode 6 by the power supply means 7. As a result, the cathode 5 and the anode 6 are charged as electrodes of one electric circuit, and the radioactive material ionized and dissolved in water in the soil 2 between the cathode 5 and the anode 6 in the trench member 3 is contaminated water. It is attracted to the cathode 5 and flows into the electrolyte solution 4 through the fine holes of the trench member 3.

  Note that the potential gradient of the soil 2 between the cathode 5 and the anode 6 is adjusted to be an appropriate value of, for example, 0.1 V / cm or more. The electrolyte solution 4 in the trench member 3 mixed with the contaminated water is taken out of the trench member 3 by the drainage means 8 and collected in the contaminated water tank 9 after reaching a predetermined contamination concentration. By this treatment, the radioactive substance is removed from the soil 2. Further, the drain member 8 replenishes the trench member 3 with a new electrolyte solution 4 according to the amount of drained electrolyte solution 4 mixed with contaminated water from the trench member 3. The level of the electrolyte solution 4 can be maintained.

  According to the radioactive substance removing device 1 described above, the trench member 3 having water permeability is embedded in the soil 2, the electrolyte solution 4 is stored in the trench member 3, and the cathode 5 is immersed in the electrolyte solution 4. Electrolyte solution 4 in which contaminated water containing radioactive material is collected in trench member 3 by inserting anode 6 into soil 2 at an interval and applying a voltage between anode 6 and cathode 5 and mixed with contaminated water. The radioactive substance removal method of removing a radioactive substance from the soil 2 by discharging | emitting from the trench member 3 is easily realizable.

  According to the radioactive substance removing device 1 and the radioactive substance removing method according to the embodiment described above, the electrolyte solution 4 is stored in the water permeable trench member 3 and the cathode 5 is immersed therein. When a negative voltage is applied, the negative voltage is transmitted to the electrolyte solution 4 and the entire trench member 3 acts as a cathode for the soil 2.

  Therefore, as shown in FIG. 1, contaminated water in a wide range of soil 2 corresponding to the length L, the buried depth d, and the interval X of the trench member 3 can be efficiently attracted to the trench member 3 and recovered. . Thereafter, the electrolyte solution 4 mixed with the radioactive substance is drained from the trench member 3 by the drainage means 8, so that the radioactive substance can be efficiently removed from the soil 2 over a wide range.

  Next, the radioactive substance removal apparatus 1 which concerns on 2nd embodiment of this invention is demonstrated using FIG. As shown in FIG. 4, the radioactive substance removing device 1 according to the second embodiment is obtained by changing the configuration of the anode 6 to the same configuration as that of the cathode 5. Specifically, the electrolyte solution 4 is stored in the trench member 3, and an anode 6 made of a metal pipe is immersed in the electrolyte solution 4.

  According to such a configuration, movement or transportation of contaminated water in the soil 2 can be promoted by periodically switching between plus and minus of the power supply means 7 and changing the direction of the current. Since the other configuration is the same as that of the radioactive substance removing device 1 according to the first embodiment shown in FIG. 1, detailed description thereof is omitted here.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments, and various modifications within the scope of the claims. Needless to say, examples or modifications also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Radioactive substance removal apparatus 2 Soil 2a Ground surface 3 Trench member 3a Straight trench member 3b End trench member 4 Electrolyte solution 5 Cathode 5a Cathode terminal 5b Cathode electric wire 5c Negative electric wire 5d Negative electric power line 6 Anode 6a Anode terminal 6b Anode electric wire 6c Plus electric wire 6d plus power line 7 power supply means 7a power generation means 7b AC / DC converter 7c DC power supply 7d minus terminal box 7e plus terminal box 8 drainage means 8a drain pipe 8b suction pump 8c on-off valve 8d check valve 9 contaminated water tank 10 water supply Means 10a Water supply pipe

Claims (6)

A method for removing radioactive material from soil contaminated with radioactive material, comprising:
A trench member having water permeability is embedded in the soil,
Storing the electrolyte solution in the trench member;
Immerse the cathode in the electrolyte solution,
Inserting an anode into the soil at a distance from the trench member,
Collecting contaminated water containing the radioactive material in the trench member by applying a voltage between the anode and the cathode;
Removing the radioactive material from the soil by discharging the electrolyte solution mixed with the contaminated water from the trench member;
The radioactive substance removal method characterized by the above-mentioned. A radioactive substance removal device for removing radioactive substances from soil contaminated with radioactive substances,
A trench member having water permeability and embedded in the soil;
An electrolyte solution stored in the trench member;
A cathode immersed in the electrolyte solution;
An anode inserted into the soil at a distance from the trench member;
Power supply means for applying a voltage between the anode and the cathode;
Drainage means capable of draining the liquid in the trench member,
By applying a voltage between the anode and the cathode, the contaminated water containing the radioactive substance is recovered in the trench member, and the electrolyte solution mixed with the contaminated water is discharged from the trench member. Removing the radioactive material from the soil;
The radioactive substance removal apparatus characterized by the above-mentioned.   The radioactive substance removing device according to claim 2, wherein the trench member has an open top and is embedded so as to protrude from the surface of the soil.   4. The radioactive substance according to claim 2, wherein a plurality of the trench members are disposed substantially parallel to the soil at intervals, and the anode is disposed between the trench members. 5. Removal device.   5. The radioactive substance removing device according to claim 2, wherein a plurality of the anodes are arranged substantially in parallel along a longitudinal direction of the trench member. The radioactive substance removing device according to any one of claims 2 to 5, wherein the power supply means is configured by a solar power generation device, a wind power generation device, or another renewable energy power generation device. .