JP2014070986A - Nuclide conversion method and nuclide conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the amount of nuclide conversion in a nuclide conversion device and a nuclide conversion method, capable of performing nuclide conversion with a relatively small-scale device compared with a large-scale device such as an accelerator and an atomic furnace.SOLUTION: In the nuclide conversion method using a nuclide conversion device 1 comprising: a tubular structural body 2; a heavy hydrogen high concentration part 3 through which an electrolyte including heavy water and the substance to be subjected to nuclide conversion can circulate; and a heavy hydrogen low concentration part 4 located at the outside of the structure 2, the electrolyte is fed to the heavy hydrogen high concentration part 3, the electrolyte is electrolyzed, thus heavy hydrogen is generated to make a state where the concentration of heavy hydrogen is high in the vicinity of the surface on the side of the heavy hydrogen concentration part 3 in the structure 2, and further, to make a state where the concentration of heavy hydrogen is low to the heavy hydrogen high concentration part 3 in the heavy hydrogen low concentration part 4, the structure 2 is passed through from the heavy hydrogen high concentration part 3 toward the heavy hydrogen low concentration part 3, thus the substance to be subjected to nuclide conversion in the structure 2 is subjected to nuclide conversion by the heavy hydrogen.

Description

  The present invention relates to a radionuclide conversion method and a radionuclide conversion apparatus related to a radioactive waste treatment technique, a technique for generating a rare element from elements abundantly present in nature, an energy generation technique using an agglomeration-type nuclear reaction, and the like.

  Patent Document 1 discloses a nuclide conversion apparatus and a nuclide conversion method capable of performing nuclide conversion with a relatively small apparatus as compared with a large apparatus such as an accelerator or a nuclear reactor.

  The nuclide conversion device disclosed in Patent Document 1 includes a hydrogen storage metal or a hydrogen storage alloy such as palladium (Pd) or a palladium alloy, and a material having a relatively low work function (calcium oxide: CaO). A laminated structure, an occlusion chamber in which the inside can be kept airtight, a discharge chamber provided in an airtight manner via the structure, deuterium supply means for supplying deuterium gas to the occlusion chamber, And an evacuation unit that evacuates the discharge chamber.

In the nuclide conversion device disclosed in Patent Document 1, a nuclide to be converted (substance subjected to nuclide conversion) is added to one surface of the structure using a technique such as vapor deposition, and a substance subjected to nuclide conversion is added. A deuterium (D ₂ ) gas is permeated from the added surface to induce a nuclear reaction, and a substance subjected to nuclide conversion is converted into another nuclide.

  In the nuclide conversion device having the above-described configuration, the progress of stable nuclear reaction and the amount of conversion can be controlled by adding a substance capable of nuclide conversion to the surface of a structure in which a nanoscale thin film such as CaO is combined with Pd. Increase can be promoted.

Japanese Patent No. 4346838 (paragraphs [0009] to [0014])

The nuclide conversion amount in the nuclide conversion device described in Patent Document 1 is on the order of several to several tens of ng / cm ² , and it is desirable to further increase the nuclide conversion amount in order to promote practical application.

  The present invention has been made in view of such circumstances, and is capable of performing nuclide conversion with a relatively small apparatus compared to a large-scale apparatus such as an accelerator or a nuclear reactor. It is an object of the present invention to provide a nuclide conversion method and a nuclide conversion apparatus that can increase the amount of nuclide conversion in an apparatus and a nuclide conversion method.

  In the first aspect of the present invention, deuterium high-concentration portion located inside a tubular structure containing palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than palladium alloy, An electrolytic solution supplying step of supplying an electrolytic solution containing a substance subjected to nuclide conversion and flowing the electrolytic solution from one end portion to the other end portion of the deuterium high concentration portion; and the supplied electrolysis A high concentration step for deuterating the solution to generate deuterium, in a state where the deuterium concentration is high in the vicinity of the surface on the deuterium high concentration portion side of the structure, and located outside the structure. The deuterium low concentration part that forms a closed space that can be sealed is made to be in a state where the concentration of deuterium is lower than that of the deuterium high concentration part, and gas is discharged from the deuterium high concentration part. Gas discharge process and said heavy A nuclide conversion step in which nuclide conversion is performed on a substance to be subjected to nuclide conversion in the structure when elemental permeates the structure from the deuterium high concentration part toward the deuterium low concentration part A nuclide conversion method comprising:

  According to a second aspect of the present invention, there is provided a tubular structure including palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than a palladium alloy, and a sealable closure located inside the structure. It is a space and is located outside the structure, and can be sealed, and an electrolyte solution containing heavy water and a substance subjected to nuclide conversion can flow from one end to the other end. A deuterium low-concentration part, which is a closed space, a voltage generation part, a positive electrode disposed at a distance from the surface of the structure on the deuterium high-concentration part side, and the electrolytic solution supplied to the deuterium high-concentration part An electrolyte solution supply unit that performs gas discharge from the deuterium high concentration portion, and a high deuterium concentration in the vicinity of the surface of the structure on the deuterium high concentration portion side. Concentration means, and deuterium reduction And a concentration reducing means for reducing the deuterium concentration in a state where the deuterium concentration is lower than that of the deuterium high concentration portion, and using the voltage generator as the structure and the positive electrode. The electrolytic solution is electrolyzed by generating a voltage difference between the deuterium and the deuterium to generate the deuterium, and the deuterium permeates the structure from the deuterium high concentration portion toward the deuterium low concentration portion. In this case, the nuclide conversion device in which the substance subjected to nuclide conversion in the structure is subjected to nuclide conversion by the deuterium.

  In the deuterium high-concentration part, an electrolytic solution containing heavy water is electrolyzed using the structure as one of the electrodes to generate deuterium, and the deuterium concentration is high in the vicinity of the structure surface. On the other hand, the deuterium low concentration part is in a state where the deuterium concentration is relatively lower than the deuterium high concentration part. Thus, a deuterium concentration gradient can be generated between the deuterium high concentration portion and the deuterium low concentration portion with the structure interposed therebetween. Due to the deuterium concentration gradient, a deuterium flux from the deuterium high concentration portion side to the deuterium low concentration portion side is formed inside the structure. Deuterium generated by electrolysis is occluded in the structure and permeates to the deuterium low concentration part side.

  Conventionally, addition of hydrogen or deuterium to a hydrogen storage metal (structure) has been performed using gas pressure. When gas pressure is used, hydrogen is physically adsorbed on the surface of the structure by van der Waals force (intermolecular force), dissociated (dissociatively adsorbed, chemisorbed), penetrated solid solution, or generated hydrogen compound. Diffusion of hydrogen atoms in the metal lattice. On the other hand, when deuterium is added to the hydrogen storage metal (structure) using electrolysis, the equivalent hydrogen pressure by electrolysis (the hydrogen pressure inside the electrode, which corresponds to the hydrogen overvoltage and electrolysis voltage) is the gas. Since the pressure is significantly higher than when pressure is used, the packing density of deuterium can be increased.

  While deuterium permeates the structure, a nuclide conversion reaction occurs between the deuterium and the substance subjected to the nuclide conversion, and the substance subjected to the nuclide conversion is converted into the nuclide. When heavy water is electrolyzed, the ion concentration of the electrolytic solution in the deuterium high concentration part becomes high. The higher the ion concentration in the electrolytic solution, the thinner the electric double in the vicinity of the structure, and the higher the electrolytic strength in the vicinity of the structure. This increases the acceleration energy of ions of the substance subjected to nuclide conversion in the electrolytic solution toward the structure, and increases the amount of the substance subjected to nuclide conversion added to the structure. Moreover, the higher the electric field strength, the more the electrolysis of heavy water at the structure (electrode) is promoted. As a result, in the nuclide conversion method of the present invention, the nuclide conversion reaction amount can be increased.

  By continuously supplying an electrolytic solution containing deuterium to the deuterium high concentration part side in the electrolytic solution supplying step, it is possible to maintain the deuterium concentration in the deuterium high concentration part within a desired range for a long period of time. Become. Therefore, the deuterium high concentration part side can be maintained for a long time in a state where the hydrogen partial pressure is high, and the nuclide conversion reaction can be continued for a long time. Moreover, since the gas that does not permeate the structure is exhausted to the outside in the gas discharge process, the inside of the deuterium high-concentration portion can be maintained within a predetermined pressure range.

  In the said aspect, it has a tubular structure. By changing the length of the structure, the reaction rate in one apparatus can be increased or decreased. Moreover, it is possible to reduce an apparatus volume by making a structure into a tubular shape.

  In one aspect of the nuclide conversion reaction, the temperature of the electrolytic solution containing ions of the substance to be subjected to the nuclide conversion before being supplied to the deuterium high concentration portion and the deuterium high concentration portion are supplied. The concentration of ions of the substance to be subjected to the nuclide conversion in the electrolytic solution in the deuterium high concentration part by adjusting the amount of the electrolytic solution and the amount of heavy water supplied to the deuterium high concentration part A density adjustment step in which

  In one aspect of the above various converters, the converter further comprises a concentration control unit that controls the concentration of the substance to be subjected to the nuclide conversion contained in the electrolytic solution in the deuterium high concentration unit, and the concentration control unit includes the electrolysis In the solution supply unit, an electrolyte salt supply means for adding an electrolyte salt containing the substance subjected to the nuclide conversion to the heavy water, an electric field solution temperature adjustment unit for adjusting the temperature of the electrolytic solution, and the electrolytic solution supply unit An electrolytic solution supply amount adjusting unit provided between the deuterium high concentration unit and adjusting the supply amount of the electrolytic solution from the electrolytic solution supply unit to the deuterium high concentration unit; and the deuterium high concentration unit A heavy water supply unit for supplying heavy water to

As described above, the higher the ion concentration of the substance subjected to nuclide conversion contained in the electrolyte solution in the vicinity of the structure, the more the amount of the substance subjected to nuclide conversion to the structure increases, and the structure Promotes electrolysis of heavy water. As a result, the nuclide conversion reaction amount can be increased.
On the other hand, the amount of electrolysis reaction of heavy water is larger than the amount of nuclide conversion reaction. For this reason, if reaction is continued, the density | concentration of the electrolyte containing the substance to which nuclide conversion will be given will become high, and electrolyte salt will precipitate. When this electrolyte salt adheres to the electrode, the above reaction is hindered and the reaction amount is reduced.

The amount of the electrolyte containing the substance subjected to nuclide conversion in the electrolytic solution depends on the temperature of the electrolytic solution. That is, by increasing the temperature of the electrolytic solution, the amount of electrolyte dissolved increases and the ion concentration in the electrolytic solution can be increased. Further, the ion concentration of the electrolytic solution can be lowered by adding heavy water to the electrolytic solution. According to the present invention, the ion concentration in the electrolytic solution in the deuterium high concentration part can be adjusted, and the nuclide conversion reaction amount can be controlled.
In addition, by adjusting the ion concentration of the substance subjected to nuclide conversion, precipitation of the electrolyte salt can be prevented.

In one aspect of the nuclide conversion reaction, the high concentration portion of deuterium is divided into a plurality of regions in the flow direction of the electrolytic solution, and the concentration of ions of the substance subjected to the nuclide conversion in each of the plurality of regions is Adjusted.
In this case, it is preferable that the heavy water is supplied to the deuterium high concentration portion in the plurality of regions.

  In one aspect of the above nuclide conversion device, the deuterium high concentration part is divided into a plurality of regions in the flow direction of the electrolytic solution, and has a plurality of the heavy water supply units. A plurality of the deuterium supply units are connected to the concentration unit.

  In the case of a tubular structure, there is a difference in ion concentration between the upstream side and the downstream side of the electrolytic solution. Therefore, if the deuterium high concentration part is divided into a plurality of regions and the ion concentration is adjusted in each region, the nuclide conversion amount is made uniform in the structure, the nuclide conversion amount is changed for each region, etc. The amount of nuclide conversion reaction can be controlled more efficiently. Moreover, precipitation of the electrolyte salt in a deuterium high concentration part can be suppressed reliably.

In one aspect of the nuclide conversion reaction, the surface of the structure on the deuterium low concentration portion side is heated to be higher than the temperature on the deuterium high concentration portion side of the structure, A temperature gradient is formed in the thickness direction.
In this case, when the deuterium high concentration portion is divided into a plurality of the regions, the surface of the structure located in the plurality of regions on the deuterium low concentration portion side in each of the plurality of regions. It is preferable to be heated.

1 aspect of the said nuclide conversion apparatus WHEREIN: The heating part which heats the said deuterium low concentration part side of the said structure to a temperature higher than the said deuterium high concentration part side of the said structure is provided.
In this case, when the deuterium high-concentration part has a plurality of regions, it is preferable that a plurality of the heating units are installed at positions corresponding to the plurality of regions.

  The hydrogen storage metal or hydrogen storage alloy constituting the structure, particularly palladium, tends to absorb hydrogen more easily at a lower temperature. Therefore, by forming a temperature gradient, deuterium is likely to be present on the surface of the deuterium high concentration portion side of the structure. Thereby, a concentration gradient of deuterium can be generated in the thickness direction of the structure, and the amount of nuclide conversion reaction can be increased.

  According to the present invention, the amount of nuclide conversion can be greatly increased by using electrolysis as a technique for relatively increasing the hydrogen pressure in the deuterium high concentration portion. Thereby, for example, it is possible to realize waste disposal that is currently impossible, such as detoxification of nuclear waste.

1 is a schematic view of a nuclide conversion apparatus according to a first embodiment. It is sectional drawing of a structure. It is a graph which shows the relationship between electrolyte concentration and the addition amount of the substance to which nuclide conversion is performed. It is the schematic of the nuclide conversion apparatus which concerns on 2nd Embodiment.

[First Embodiment]
FIG. 1 is a schematic diagram of a nuclide conversion apparatus according to the present embodiment.
The nuclide conversion apparatus 1 includes a structure 2, a deuterium high concentration unit 3, a deuterium low concentration unit 4, a high concentration unit 5, and a low concentration unit 6.

  The structure 2 has a tubular shape. The structure 2 includes palladium (Pd) or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than a palladium alloy, and a material having a relatively low work function. The substance having a relatively low work function is, for example, a substance having a work function of less than 3 eV, and specifically, CaO or the like. In the nuclide conversion device, the structure also serves as a negative electrode.

FIG. 2 shows an example of a cross section of the structure 2. The cross-sectional shape of the structure 2 in FIG. 2A is not particularly limited, such as a circle, an ellipse, a quadrangle, and a hexagon, but a circle is most preferable based on the positional relationship with the positive electrode described later.
In the structure 2, a laminated film 8 is formed inside the Pd substrate 7. FIG. 2B is an enlarged schematic view of a part of FIG. The laminated film 8 has a configuration in which, for example, ten CaO layers 8a (thickness: 2 nm) and Pd layers 8b (thickness: 20 nm) are alternately laminated. The CaO layer 8a and the Pd layer 8b are alternately formed on the Pd substrate 7 after the etching process by an argon ion beam sputtering method.
The structure 2 shown in FIG. 2 is manufactured by, for example, laminating a CaO layer and a Pd layer on a plate-like Pd substrate and then molding on a tube.

  A substance to be subjected to nuclide conversion may be added to the inner surface (opposite side of the Pd substrate 7) of the structure 2 by a film forming process such as vacuum deposition or sputtering. Examples of the substance subjected to nuclide conversion include cesium (Cs), carbon (C), strontium (Sr), sodium (Na), and the like.

  The deuterium high concentration portion 3 is defined inside the tubular structure 2. Both end portions of the tubular structure 2 are sealed with a jig 10 so that the deuterium high concentration portion 3 can be kept airtight.

  An electrolytic solution 50 is accommodated in the deuterium high concentration portion 3. A pipe 11 is connected to one jig 10, and a liquid (electrolytic solution) can be discharged from the deuterium high concentration part 3.

  The structure 2 is accommodated in the casing 12 having a larger diameter than the structure 2 so as not to contact the wall surface of the casing 12. The space between the casing 12 and the structure 2 is the deuterium low concentration portion 4. Both ends of the deuterium low concentration portion 4 are sealed by the jig 10 so that the deuterium low concentration portion 4 can be kept airtight.

A heating unit 13 is installed on the outer periphery of the casing 12. The heating unit 13 is a nichrome heater or the like. A controller (not shown) for detecting and controlling the temperature on the deuterium low concentration portion side of the structure 2 is connected to the heating unit 13. The control device includes a thermocouple (not shown) that can detect the temperature on the deuterium high concentration part 3 side and the temperature on the deuterium low concentration part 4 side of the structure 2. As for the temperature on the deuterium high concentration part 3 side, the temperature of the structure 2 may be directly measured, or the temperature of the electrolytic solution 50 in the deuterium high concentration part 3 may be measured.
Based on the temperature of the deuterium low concentration portion side of the structure 2 and the temperature of the electrolytic solution in the deuterium high concentration portion 3, the deuterium low concentration portion 4 side (Pd substrate side) of the structure 2 is set to a predetermined temperature. The heating unit 13 is controlled so as to be.

  The high concentration means 5 includes a voltage generator 14, a positive electrode 15, an electrolytic solution supply unit 16, and a gas discharge path 17.

  The positive electrode 15 is a platinum rod or the like. The positive electrode 15 is disposed inside the deuterium high-concentration portion 3 and is spaced from the inner side surface (surface on the deuterium high-concentration portion side) of the structure 2. At this time, if the cross section of the structure 2 is circular and the positive electrode is disposed at the center position of the circle, the electric field strength between the positive electrode 15 and the structure 2 (negative electrode) can be made substantially constant.

  The voltage generator 14 is located outside the deuterium high concentration part 3 and gives a voltage difference between the positive electrode 15 and the structure 2 (negative electrode).

  The electrolytic solution supply unit 16 includes a first electrolytic solution tank 20, a second electrolytic solution tank 30, electrolytic solution supply paths 21, 31, dehumidifying units 22, 32, and a gas source (not shown).

  The first electrolytic solution tank 20 stores a solution containing deuterium (heavy water) as an electrolytic solution. The first electrolytic solution tank 20 is connected to the second electrolytic solution tank 30 via the electrolytic solution supply path 21. One end of the electrolytic solution supply path 21 is disposed so as to be immersed in heavy water 52 accommodated in the first electrolytic solution tank 20. A valve 23 is provided in the electrolytic solution supply path 21.

  An electrolytic solution 51 is accommodated in the second electrolytic solution tank 30. One end of the electrolytic solution supply path 31 is disposed so as to be immersed in the electrolytic solution 51 accommodated in the second electrolytic solution tank 30. The other end of the electrolytic solution supply path 31 is connected to one of the jigs 10. Thereby, the second electrolytic solution tank 30 and the deuterium high concentration unit 3 are connected via the electrolytic solution supply path 31. A valve 33 is provided in the electrolytic solution supply path 31.

Dehumidifying sections 22 and 32 and a gas source are connected to the first electrolytic solution tank 20 and the second electrolytic solution tank 30 through gas supply paths 24 and 34, respectively. Valves 25 and 35 are installed in the gas supply paths 24 and 34, respectively. The dehumidifying sections 22 and 32 are filters with a dehumidifying function such as silica gel. The gas source is a cylinder filled with an inert gas, for example, a nitrogen (N ₂ ) cylinder, an argon (Ar) cylinder, or a CE (Cold Evaporator).

  The gas discharge path 17 is connected to the deuterium high concentration section 3 via a check valve (<1 atm) 18 so that the gas in the deuterium high concentration section 3 can be discharged to the outside.

  The deuterium low concentration unit 4 includes a low concentration means 6. In FIG. 1, the concentration reducing means 6 is an exhaust device such as a turbo molecular pump and a dry pump, and the deuterium pressure is lower in the deuterium low concentration portion 4 than in the deuterium high concentration portion 3 by evacuation. Maintain state.

The concentration reducing means 6 may be configured to include an inert gas supply device and a discharge path. In this case, the inert gas supply device includes a gas source and a dehumidifying unit. Examples of the gas source include a nitrogen (N ₂ ) cylinder, an argon (Ar) cylinder, and a CE (Cold Evaporator). The exhaust path is connected to the deuterium low concentration part 4 via a check valve.

  The nuclide conversion device 1 of the present embodiment includes a concentration control unit. The concentration control unit includes an electrolyte salt supply unit, an electrolytic solution temperature adjustment unit 41, an electrolytic solution supply amount adjustment unit, and a heavy water supply unit 42.

In FIG. 1, the electrolyte salt supply means is an electrolyte salt 40 including a substance to be subjected to nuclide conversion disposed in the second electrolytic solution tank 30. The electrolyte salt 40 is disposed at a position where part or all of the electrolyte salt 40 is immersed in the electrolyte solution 51 like the bottom of the second electrolyte solution tank 30. The electrolyte salt supply means is configured as an apparatus configuration in which an electrolyte salt containing a substance to be subjected to nuclide conversion is introduced into the electrolyte solution 51 from the outside of the second electrolyte solution tank 30 (for example, a tank and a valve for storing the electrolyte salt). Also good. The electrolyte salt containing the substance subjected to nuclide conversion is, for example, CsNO ₃ , CsOH, NaNO ₃ , Sr (NO ₃ ) ₂ , Ba (NO ₃ ) ₂ or the like. In the electrolytic solution 51 in the second electrolytic solution tank 30, an electrolyte salt containing a substance to be subjected to nuclide conversion is dissolved. Therefore, the electrolytic solution 51 contains ions (for example, Cs ⁺ , Sr ^2+, etc.) of the substance to be subjected to nuclide conversion.

  As the electrolytic solution temperature adjusting unit 41, a heater is installed around the second electrolytic solution tank 30. The heater adjusts the temperature of the electrolytic solution 51 in the second electrolytic solution tank 30.

  The electrolytic solution supply amount adjusting unit is a valve 33 provided in the electrolytic solution supply path 31. The amount of electrolytic solution supplied to the deuterium high concentration part 3 is controlled by the opening degree of the valve 33.

  The heavy water supply unit 42 includes a third electrolytic solution tank 43, a heavy water supply path 44, a valve 45, and a gas source (not shown).

  The third electrolytic solution tank 43 stores a solution containing deuterium (heavy water). One end of the heavy water supply path 44 is disposed so as to be immersed in the heavy water 53 accommodated in the third electrolytic solution tank 43. In FIG. 1, the other end of the heavy water supply path 44 is connected to the electrolytic solution supply path 31. As a result, the third electrolytic solution tank 43 is connected to the deuterium high concentration part 3 via the heavy water supply path 44 and the electrolytic solution supply path 31. Alternatively, the other end of the heavy water supply path 44 may be directly connected to one jig 10. A valve 45 is provided in the heavy water supply path 44.

  A dehumidifying unit 47 and a gas source are connected to the third electrolytic solution tank 43 via a gas supply path 46. A valve 48 is installed in each gas supply path 46. The gas supply path 46, the dehumidifying unit 47, and the gas source have the same configuration as the electrolytic solution supply unit 16.

  A concentration measurement unit 49 is connected to the deuterium high concentration unit 3. The concentration measuring unit 49 is an ion concentration meter or a pH meter, and measures the ion concentration in the electrolytic solution in the deuterium high concentration unit 3.

A nuclide conversion method using the nuclide conversion apparatus of the first embodiment will be described.
In the nuclide conversion device of FIG. 1, the deuterium high concentration portion 3 and the deuterium low concentration portion 4 are sealed in a liquid-tight and air-tight state by a jig 10.

(Electrolytic solution supply process)
The electrolytic solution supply unit 16 supplies the electric field solution into the deuterium high concentration unit 3.
CE (Cold Evaporator) _N ₂ is supplied from the gas source to the first electrolytic solution tank 20 through the gas supply path 24 and the dehumidifying unit 22. Heavy water in the first electrolytic solution tank 20 is transported from the first electrolytic solution tank 20 to the second electrolytic solution tank 30 via the electrolytic solution supply path 21 with N ₂ .

  In the second electrolytic solution tank 30, the electrolyte salt 40 containing the substance to be subjected to nuclide conversion is dissolved in the electrolytic solution 51. The concentration of ions of the substance subjected to nuclide conversion in the second electrolytic solution tank 30 is adjusted by the supply amount of the electrolytic solution to the second electrolytic solution tank 30 and the temperature of the electrolytic solution 51. When the electrolyte salt is introduced from outside the system, the ion concentration is also adjusted by the supply amount of the electrolyte salt.

  An electrolytic solution 51 containing ions of a substance to be subjected to nuclide conversion is supplied from the second electrolytic solution tank 30 to the deuterium high concentration unit 3 via the electrolytic solution supply path 31. Simultaneously with the supply of the electrolytic solution, the electrolytic solution is discharged from the deuterium high concentration portion 3 through the pipe 11. Thereby, in the deuterium high concentration part 3, the flow of the electrolyte solution toward the other end part connected to the piping 11 from one end part connected to the electrolyte solution supply path 21 is generated. The supply amount of the electrolytic solution to the deuterium high concentration part 3 is controlled so that the amount of the electrolytic solution 50 in the deuterium high concentration part 3 is always immersed in the positive electrode 15.

(Low concentration process)
The deuterium low concentration portion 4 is brought into a low deuterium pressure state by the concentration reducing means 6. In detail, the inside of the deuterium low concentration part 4 is made into a vacuum state using a vacuum pump, and this is maintained. The pressure in the deuterium low concentration portion 4 is preferably <0.1 Pa.

  When an inert gas supply device and an exhaust path are installed as the concentration reducing means 6, the inert gas supply device supplies an inert gas to the deuterium low concentration portion 4. When the pressure in the deuterium low concentration portion 4 exceeds a predetermined value (1 atm), the check valve is opened and the gas in the deuterium low concentration portion 4 is exhausted to the outside. By making the deuterium low concentration part 4 into an inert environment, the deuterium partial pressure in the deuterium low concentration part 4 is maintained substantially at zero.

(High concentration process)
The voltage generator 14 applies power to the positive electrode 15 to generate a voltage difference between the positive electrode 15 and the negative electrode (structure) 2. The voltage difference is at least 2V. As a result, heavy water (D ₂ O) is electrolyzed on the inner surface (surface opposite to the Pd substrate) of the structure 2 to generate deuterium gas (D ₂ ) and oxygen gas. If the voltage difference is less than 2V, the electrolysis reaction does not proceed sufficiently.
A deuterium concentration gradient is generated between the deuterium high concentration portion 3 and the deuterium low concentration portion 4 with the structure 2 interposed therebetween, and deuterium permeates the structure 2 from the deuterium high concentration portion 3 to deuterium. Move to the low concentration part 4.

In the present embodiment, a heating step may be performed at this time.
(Heating process)
The deuterium low concentration part 4 side is heated to a predetermined temperature by the heating part 13. Specifically, the temperature of the deuterium low concentration part 4 side (Pd substrate side) and the deuterium high concentration part 3 side (opposite side of the Pd substrate or the electrolytic solution 50) of the structure 2 are measured by the control device. The obtained temperature information is transmitted to the control device. The control device controls the heating of the structure 2 by the heating unit 13 based on the temperature information.

  The Pd layer 8b, which is a layer on the surface of the structure 2, has a characteristic of easily storing deuterium at a low temperature. By cooling the electrolytic solution 50, the amount of deuterium charged on the deuterium high concentration part 3 side (Pd layer) of the structure 2 is increased. Since the nuclide conversion amount depends on the deuterium amount, the nuclide conversion amount can be increased by increasing the deuterium density of the structure 2.

  On the other hand, a higher temperature of the structure 2 can promote deuterium diffusion. By heating the deuterium low concentration portion 4 side of the structure 2 and forming a temperature gradient in the thickness direction of the structure, the permeation amount of deuterium can be increased.

  Therefore, the heating unit 13 warms the structure 2 on the deuterium low concentration part 4 side so that the temperature on the deuterium low concentration part 4 side becomes higher than the temperature on the deuterium high concentration part 3 side. The temperature gradient at this time is preferably about 50 ° C.

(Nuclide conversion process)
As described above, due to the concentration gradient and the temperature gradient, deuterium gas permeates through the structure 2 from the deuterium high concentration portion 3 side toward the deuterium low concentration portion 4 side. When power is applied to the positive electrode 15 by the voltage generator 14, ions of a substance to be subjected to nuclide conversion in the electrolytic solution move to the structure 2 (negative electrode) side and enter the structure 2.

When deuterium permeates through the structure 2, the substance (ion) subjected to nuclide conversion in the structure 2 is nuclide converted. For example, nuclide conversion reactions such as ¹³³ Cs → ¹⁴¹ Pr, ¹³⁸ Ba → ¹⁵⁰ Sm, ⁸⁸ Sr → ⁹⁶ Mo, ²³ Na → ²⁷ Na → ²⁷ Mg → ²⁷ Al occur. In addition, when C is added to the structure 2 in advance as a substance to be subjected to nuclide conversion, a reaction of ¹² C → ²⁴ Mg → ²⁸ Si → ³² S occurs.

  The amount of nuclide conversion reaction depends on the amount of deuterium permeated into the structure and the amount of ions of the substance to be subjected to nuclide conversion attached to the structure.

  When the voltage difference between the positive electrode 15 and the structure 2 is constant, the higher the ion concentration in the electrolytic solution of the deuterium high concentration part 3, the higher the electric double layer on the surface of the positive electrode 15 and the structure 2 (negative electrode). The thickness becomes thinner. Since the electric field strength in the electric double layer is increased, the energy by which ions of the substance subjected to nuclide conversion are accelerated toward the structure 2 is increased.

FIG. 3 is a graph showing the interrelationship between the concentration of the electrolyte salt (CsNO ₃ ) in the electrolytic solution (heavy water base) and the amount of Cs adhering to the surface of the structure. In the figure, the horizontal axis represents CsNO ₃ concentration, and the vertical axis represents Cs adhesion amount. In the structure, a total of 10 Pd layers and CaO layers were alternately laminated on a flat Pd substrate in the same manner as in FIG. After maintaining the voltage difference between the positive electrode and the negative electrode at 1 V for 10 seconds, the amount of Cs adhering to the surface of the structure was measured using ICP = MS. As shown in FIG. 3, the higher the ion concentration in the electrolytic solution, the greater the amount of the substance that is subjected to nuclide conversion that adheres to the structure.
The higher the electric field strength at the electric double layer, the more the electrolysis reaction at the positive electrode 15 and the structure 2 (negative electrode) is promoted. For this reason, the amount of generated deuterium also increases.

Therefore, the higher the ion concentration in the electrolytic solution, the greater the amount of nuclide conversion reaction. That is, the nuclide conversion amount can be controlled by adjusting the ion concentration. The amount of the nuclide conversion reaction that is most increased is the saturation concentration of the electrolyte salt containing the substance that performs the nuclide conversion. For example, the saturation concentration at 20 ° C. is 1.2 mol / l for CsNO ₃ and 26.3 mol / l for CsOH.

  Further, the amount of heavy water consumed in the electrolysis reaction is larger than the amount of ions subjected to the nuclide conversion consumed in the nuclide conversion reaction. For this reason, with the continuation of the reaction, the ion concentration in the electrolytic solution in the deuterium high concentration part 3 becomes high, and the electrolyte salt is deposited on the electrode surface and the wall surface exceeding the saturation concentration. When the electrolyte salt is deposited on the electrode surface, the above reaction is suppressed.

The present embodiment may include a concentration adjusting step for adjusting the ion concentration of a substance subjected to nuclide conversion in the electrolytic solution in the deuterium high concentration portion 3. The concentration adjustment step can control the amount of nuclide conversion reaction in addition to suppressing the precipitation of the electrolyte salt.
(Density adjustment process)
The ion concentration in the electrolytic solution in the deuterium high concentration unit 3 is managed by the concentration measurement unit 49. Based on the ion concentration acquired by the concentration measuring unit 49, the ion concentration in the deuterium high concentration unit 3 is adjusted.

  When increasing the ion concentration, the ion concentration in the electrolytic solution 51 in the second electrolytic solution tank 30 is increased, and the supply amount of the electrolytic solution 51 from the second electrolytic solution tank 30 is increased. In order to increase the ion concentration in the electrolytic solution 51, the electrolytic solution temperature adjustment unit 41 increases the temperature of the electrolytic solution 51. When the electrolyte salt is charged into the second electrolytic solution tank 30 from outside the system, the charging amount may be increased as the temperature rises. The supply amount of heavy water 52 from the first electrolytic solution tank 20 is adjusted so that the water level of the electrolytic solution 51 in the second electrolytic solution tank 30 can be secured.

  When decreasing the ion concentration, the ion concentration in the electrolytic solution 51 in the second electrolytic solution tank 30 is decreased and the ratio of heavy water in the deuterium high concentration part 3 is increased. In order to reduce the ion concentration in the electrolytic solution 51, the temperature of the electrolytic solution 51 is lowered by the electrolytic solution temperature adjustment unit 41. In order to increase the ratio of heavy water in the deuterium high-concentration part 3, the supply amount of the electrolytic solution 51 from the second electrolytic solution tank 30 is reduced or the valve 45 is opened, and the heavy water is discharged from the third electrolytic solution tank 43. 53 is supplied to the deuterium high concentration part 3.

  As described above, when the supply amount of the electrolytic solution to the deuterium high concentration part 3 is varied, the supply amount of the electrolytic solution is adjusted so that the positive electrode 15 and the structure 2 are located below the electrolytic solution level. To do.

  Moreover, in the deuterium high concentration part 3, since the electrolysis reaction of heavy water is progressing in the downstream area in the flow direction of the electrolytic solution, the electrolyte concentration tends to be high. For this reason, the concentration measuring unit 49 is installed on the downstream side of the electrolytic solution of the deuterium high concentration unit 3, and in the deuterium high concentration unit 3 according to the ion concentration in the electrolytic solution of the deuterium high concentration unit 3 on the downstream side. The temperature of the electrolytic solution may be increased. In this case, the temperature of the electrolytic solution 51 may be increased by the electrolytic solution temperature adjustment unit 41, or the temperature of the heating unit 13 may be increased within a range in which the increased temperature gradient is maintained.

(Gas discharge process)
When electrolysis proceeds in the deuterium high concentration part 3, deuterium gas and oxygen gas are generated accordingly. Further, when supplying the electrolytic solution to the deuterium high concentration part 3, nitrogen gas flows into the deuterium high concentration part 3. In the present embodiment, the check valve 18 is opened when the pressure in the deuterium high concentration portion 3 becomes 1 atm (1 × 10 ⁵ Pa) or more, and excess deuterium gas, oxygen from the deuterium high concentration portion 3 is opened. Gas and nitrogen gas are discharged.

In the nuclide conversion apparatus 1 of FIG. 1, there is one casing 12 (deuterium high concentration portion 3 and deuterium low concentration portion 4) that is a section that causes a nuclide conversion reaction. . By carrying out like this, the reaction amount in one nuclide conversion device 1 can be raised. In this case, the electrolytic solution supply unit 16 is shared by the plurality of casings 12, and the casing 12 is connected in parallel to the flow of the electrolytic solution. The deuterium low concentration portion 4 may be connected in common by the plurality of casings 12.
In this embodiment, since the structure 2 is tubular, the capacity of the casing 12 can be reduced, and even when a plurality of casings 12 are installed, there is an advantage that the apparatus capacity can be reduced.

[Second Embodiment]
FIG. 4 is a schematic diagram of a nuclide conversion apparatus according to the second embodiment. About the structure which is not demonstrated especially, it is set as the structure similar to the nuclide converter of 1st Embodiment, and the same code | symbol is attached | subjected.
In the nuclide conversion device 100 of the present embodiment, the deuterium high concentration part 3 is divided into a plurality of regions (three regions 101a to 101c in FIG. 4) in the flow direction of the electrolytic solution. The number of regions to be divided is appropriately set according to the length of the structure 2 (deuterium high concentration portion 3).

  In each of the regions 101a to 101c, the heavy water supply units 102a to 102c are connected to the deuterium high concentration unit 3, respectively. The heavy water supply units 102a to 102c have the same configuration as that of the first embodiment. The heavy water supply units 102a to 102c supply heavy water to the regions 101a to 101c of the deuterium high concentration unit 3, respectively. Concentration measuring units 103a to 103c that measure the ion concentration in the deuterium high concentration unit 3 are installed at positions corresponding to the regions 101a to 101c.

  Heating portions 104a to 104c are installed on the outer periphery of the casing 12 at positions corresponding to the regions 101a to 101c.

A nuclide conversion method using the nuclide conversion apparatus of the second embodiment will be described.
Similarly to the first embodiment, the electrolytic solution supply process, the concentration reduction process, and the concentration increase process are performed.

(Heating process)
The deuterium low concentration part 4 side is heated to a predetermined temperature by the heating parts 104a to 104c. The temperature control process of each heating part 104a-104c is the same as that of 1st Embodiment. Heating by the heating units 104a to 104c is performed independently. By doing so, the amount of deuterium permeation in each region can be changed, and the amount of nuclide conversion reaction in each region can be controlled.

(Nuclide conversion process)
As in the first embodiment, the substance subjected to nuclide conversion in the structure 2 is nuclide converted.
First, in the region 101a, an electrolytic reaction and a nuclide conversion reaction of the electrolytic solution supplied from the electrolytic solution supply unit 16 to the deuterium high concentration unit 3 occur. The amount of heavy water consumed by the electrolysis reaction is larger than the amount of ions consumed by the nuclide conversion reaction. For this reason, when the reaction is continued in the region 101a, the ion concentration in the electrolytic solution in the region 101a becomes high.
The electrolytic solution having a high ion concentration flows in the deuterium high concentration portion 3 from the region 101a toward the region 103b and the region 103c. In the regions 101b and 101c, a reaction similar to that in the region 101a occurs.

(Density adjustment process)
As described above, ions in the electrolytic solution are concentrated by electrolysis of heavy water. Similar to the first embodiment, the ion concentration in the deuterium high concentration part 3 is adjusted so that the electrolyte salt does not precipitate in the deuterium high concentration part 3 and to control the nuclide conversion reaction amount. . In the present embodiment, the ion concentrations of the regions 101a to 101c are adjusted independently.

  The concentration measuring units 103a to 103c measure the ion concentration in the electrolytic solution in the deuterium high concentration unit 3 in the installed regions 101a to 101c.

  When increasing the ion concentration, the ion concentration in the electrolytic solution 51 in the second electrolytic solution tank 30 is increased by the same method as in the first embodiment, and the supply amount of the electrolytic solution 51 from the second electrolytic solution tank 30 is increased. Increase. Regarding the region 101b and the region 101c, the electrolytic solution concentration in the region 101a can be increased by increasing the amount of electrolysis in the region 101a.

  When reducing the ion concentration, the ion concentration in the electrolytic solution 51 in the second electrolytic solution tank 30 is reduced by the same method as in the first embodiment. Further, heavy water is supplied from the heavy water supply units 102a to 102c via the heavy water supply paths 105a to 105c, and the ratio of heavy water in the deuterium high concentration unit 3 is increased. At this time, heavy water from the third electrolytic solution tanks 107a to 107c is adjusted by adjusting the opening degree of the valves 106a to 106c in each of the regions 101a to 101c based on the ion concentrations measured by the concentration measuring units 103a to 103c. Adjust the supply amount.

  When the heating amount by the heating units 104a to 104c is changed in each region, the deuterium permeation amount in each region can be changed. It is also possible to adjust the ion concentration in the electrolytic solution in each region by changing the temperature of the heating units 104a to 104c.

Specifically, the electrolyte concentration tends to be higher in the region 104c on the downstream side than the region 104a on the upstream side in the flow direction of the electrolytic solution because the heavy water electrolysis reaction proceeds. When the concentration of the electrolyte salt exceeds the saturation concentration in the downstream region 104c, the electrolyte salt is deposited on the electrode surface and the wall surface. When the electrolyte salt is deposited on the electrode surface, the above reaction is suppressed.
In this embodiment, you may adjust the temperature of the heating parts 104a-104c so that temperature may become high as the area | region of a downstream side. In this case, the temperature gradient between the deuterium high concentration part 3 and the deuterium low concentration part 4 described in the first embodiment is adjusted to be maintained. By so doing, even if the amount of heavy water decreases due to the electrolysis reaction on the downstream side of the electrolytic solution, the saturation concentration of the electrolyte salt increases, so that precipitation can be suppressed.

1,100 nuclide conversion device 2 structure (negative electrode)
3 Deuterium high concentration part 4 Deuterium low concentration part 5 High concentration means 6 Low concentration means 7 Pd substrate 8 Laminated film 8a CaO layer 8b Pd layer 10 Jig 11 Pipe 12 Casing 13, 104a-104c Heating part 14 Voltage generator 15 Positive electrode 16 Electrolytic solution supply unit 17 Gas discharge path 18 Check valve 20 First electrolytic solution tanks 21, 31 Electrolytic solution supply paths 22, 32, 47 Dehumidifying units 23, 25, 33, 35, 45, 48, 106a-106c Valves 24, 34, 46 Gas supply path 30 Second electrolytic solution tank 40 Electrolyte salt 41 Electrolytic solution temperature adjustment unit 42, 102a-102c Heavy water supply unit 43, 107a-107c Third electrolytic solution tank 44, 105a-105c Heavy water supply unit 49, 103a to 103c Concentration measuring unit 50, 51 Electrolytic solution 52, 53 Heavy water 101a to 101c region

Claims (11)

Deuterium and a substance to be subjected to nuclide conversion in a high concentration portion of deuterium located inside a tubular structure containing palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than palladium alloy. An electrolytic solution supplying step of supplying an electrolytic solution containing, and circulating the electrolytic solution from one end portion of the deuterium high concentration portion toward the other end portion;
Electrolyzing the supplied electrolyte solution to generate deuterium, and increasing the concentration of deuterium near the surface of the structure on the deuterium-enriched portion side;
A low concentration step in which a deuterium low concentration portion located outside the structure and forming a sealable closed space is in a state where the concentration of deuterium is lower than the high concentration portion of deuterium;
A gas discharging step of discharging gas from the deuterium high concentration part;
When the deuterium permeates the structure from the deuterium high-concentration part toward the deuterium low-concentration part, the nuclide whose nuclide is converted into the nuclide by the deuterium in the structure A nuclide conversion method comprising a conversion step.   The temperature of the electrolytic solution containing ions of the substance subjected to the nuclide conversion before being supplied to the deuterium high concentration part, the amount of the electrolytic solution supplied to the deuterium high concentration part, and the heavy ion A concentration adjusting step in which the amount of heavy water supplied to the high hydrogen concentration portion is adjusted to adjust the concentration of ions of the substance subjected to the nuclide conversion in the electrolytic solution in the high deuterium concentration portion. The nuclide conversion method according to claim 1.   The deuterium high concentration part is divided into a plurality of regions in the flow direction of the electrolytic solution, and the concentration of ions of the substance subjected to the nuclide conversion is adjusted in each of the plurality of regions. Radionuclide conversion method.   The nuclide conversion method according to claim 3, wherein the heavy water is supplied to the deuterium high concentration portion in the plurality of regions.   The surface on the deuterium low concentration portion side of the structure is heated to be higher than the temperature on the deuterium high concentration portion side of the structure to form a temperature gradient in the thickness direction of the structure. The nuclide conversion method according to any one of claims 1 to 4.   When the deuterium high concentration portion is divided into a plurality of the regions, the surface of the structure located in the plurality of regions on the deuterium low concentration portion side is heated in each of the plurality of regions. The nuclide conversion method according to claim 5. A tubular structure containing palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than palladium alloy;
A closed space that can be sealed inside the structure, and a high concentration portion of deuterium in which an electrolytic solution containing heavy water and a substance subjected to nuclide conversion can flow from one end to the other end; ,
A deuterium low-concentration portion which is located outside the structure and is a closed space that can be sealed;
A voltage generator, a positive electrode disposed at a distance from a surface on the deuterium high concentration portion side of the structure, an electrolytic solution supply unit for supplying the electrolytic solution to the deuterium high concentration portion, and the deuterium high A high concentration means comprising a gas discharge path for discharging gas from the concentration portion, and a state in which the concentration of deuterium is high in the vicinity of the surface on the deuterium high concentration portion side of the structure;
A concentration reducing means for setting the deuterium low concentration portion to a state in which the concentration of the deuterium is lower than the deuterium high concentration portion;
With
Using the structure as a negative electrode, the voltage generator applies a voltage difference between the structure and the positive electrode to electrolyze the electrolytic solution to generate the deuterium,
When the deuterium permeates the structure from the deuterium high-concentration part toward the deuterium low-concentration part, the nuclide whose nuclide is converted into the nuclide by the deuterium in the structure Conversion device. A concentration control unit for controlling the concentration of the substance subjected to the nuclide conversion contained in the electrolytic solution in the deuterium high concentration unit;
The concentration controller
In the electrolytic solution supply unit, an electrolyte salt supply means for adding an electrolyte salt containing a substance that is subjected to the nuclide conversion to the heavy water;
An electric field solution temperature adjusting unit for adjusting the temperature of the electrolytic solution;
An electrolytic solution supply amount adjustment unit that is provided between the electrolytic solution supply unit and the deuterium high concentration unit and adjusts the supply amount of the electrolytic solution from the electrolytic solution supply unit to the deuterium high concentration unit;
A heavy water supply section for supplying heavy water to the deuterium high concentration section;
The nuclide conversion device according to claim 7 provided. The deuterium high concentration part is divided into a plurality of regions in the flow direction of the electrolytic solution,
A plurality of the heavy water supply units;
The nuclide conversion device according to claim 8, wherein the plurality of deuterium supply units are connected to the deuterium high concentration unit in each of the plurality of regions.   10. The heating device according to claim 7, further comprising a heating unit that heats the deuterium low concentration portion side of the structure to a temperature higher than that of the deuterium high concentration portion side of the structure. Nuclide conversion device.   The nuclide conversion device according to claim 10, wherein when the deuterium high concentration part has a plurality of the regions, the plurality of heating units are installed at positions corresponding to the plurality of regions.

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