JP2019093312A - Isotope separation device, isotope separation system and isotope separation method - Google Patents

Abstract

To provide a compact isotope separation device having high isotope separation efficiency, an isotope separation system and an isotope separation method.SOLUTION: An isotope separation device includes: a container 1 storing a liquid 1a containing isotopes; a mist generator 7 misting the liquid; a mist transfer pipe 4 disposed at the upper part of the container; a partition member 5a partitioning the mist transfer pipe into a plurality of regions and having a plurality of holes in which the mist can pass through; a gas 2a transferring mist 3a-3d; and a mist recovery container 9 connected to the upper part of the mist transfer pipe.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to an isotope separation apparatus, an isotope separation system and an isotope separation method for separating isotopes from liquid.

  When an accident occurs at a nuclear power plant, the main decontamination target nuclides immediately after the accident are cesium (Cs), but in recent years, the need for treatment of tritium water in stagnant water is increasing. The conventional method for treating tritium water has been dilution, but in recent years, it has been desired to separate and remove tritium water contained in stagnant water.

  Separation, concentration, recovery, and removal of tritiated water is important as a technology for improving nuclear reaction control and nuclear fuel cycle reliability in the nuclear industry, and it has also been identified in the fields of biological, chemical, medical, etc. It is also important as a label technology for elements.

  In general isotope separation methods, separation methods based on mass number differences such as diffusion methods and centrifugation methods are generally used, but as means for isotope separation such as heavy water and tritiated water, precision distillation methods, isotopes A replacement method, an electrolysis method, etc. are mentioned.

In the precision distillation method, since there is a difference in boiling point between water (H ₂ O), heavy water (D ₂ O) and tritiated water (T ₂ O), separation is performed using a distillation column. However, the difference in boiling point between tritium water and water is about 3 ° C., so the separation efficiency per stage is not high although depending on the height of the distillation column, and a large number of stages are required for treatment.

The isotope exchange method, is brought into contact with H 2 _S solvent to heavy water or tritiated water, deuterium (D), since tritium (T) moves to the H _{2 S} side was replaced with H of H _{2 S,} which D and T can be recovered by recovering and concentrating. This method is often used for separation and recovery of D and T, but has problems such as H ₂ S toxicity, corrosiveness, and complicated operation of the reaction.

Although separation is possible by the electrolytic method, the equipment cost and the large power consumption are disadvantageous.
Among the tritium separation methods used in fusion reactors, etc. instead of the polluted water from nuclear power plants, the most popular method is the isotope exchange method using a catalyst called CECE (Combined Electrolysis Catalytic Exchange).

However, this method needs to perform electrolysis with alkaline water electrolysis or solid polymer electrolyte, and perform concentration and hydrogenation of tritium, but in principle, the height of the device can not be avoided. In order to store this CECE system in a building interior, it is necessary to be arranged through multiple layers, which causes the size of the building to be increased and the number of tritium confinement spaces to increase, which causes an increase in cost. In order to miniaturize this CECE system, it is essential to develop a system that reduces the amount of processing before the CECE system.
There is also proposed a means for forming water containing heavy water, tritiated water or the like into a fine droplet and separating heavy water or tritiated water depending on the density.

Japanese Patent Publication No. 61-28603 JP, 2017-56422, A

  As mentioned above, separation systems such as precision distillation, isotope exchange, electrolysis and CECE, which have been conventionally used as separation methods for heavy water and tritiated water, require complicated processes and high processing costs. And, there was a problem that the device became large.

  Although the conventional separation system by mist formation has advantages in terms of energy saving performance and miniaturization, in order to increase the separation rate, it is necessary to multistage the separation device, and the problem that the device as a whole becomes large there were.

  The embodiment of the present invention has been made to solve the above-described problems, and an object thereof is to provide a compact isotope separation apparatus, isotope separation system, and isotope separation method with high separation efficiency.

  In order to solve the above-mentioned subject, the isotope separation device concerning this embodiment is provided in the upper part of the container in which the liquid containing an isotope is stored, the misting device which atomizes the liquid, and the container. An isotope separator comprising a mist transfer pipe, a partition member for dividing the mist transfer pipe into a plurality of regions, a gas for transferring the mist, and a mist recovery container connected to an upper portion of the mist transfer pipe The partition member may have a plurality of holes through which mist can pass.

Moreover, the isotope separation system according to the present embodiment is characterized in that a plurality of isotope separation devices according to the embodiment of the present invention are arranged in parallel and / or in series.
Moreover, the isotope separation method according to the present embodiment is characterized in that isotope separation is performed using the isotope separation device according to the embodiment of the present invention.

  According to an embodiment of the present invention, a compact isotope separation device, isotope separation system and isotope separation method with high isotope separation efficiency can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the isotope separator which concerns on 1st Embodiment. 6 is a demonstration test example using the isotope separation device according to the first embodiment. The block diagram of the isotope separator which concerns on 2nd Embodiment. The block diagram of the isotope separator which concerns on 3rd Embodiment. The block diagram of the isotope separator which concerns on 4th Embodiment. The block diagram of the isotope separation system which concerns on 5th Embodiment.

Hereinafter, embodiments of the isotope separation apparatus, the isotope separation system, and the isotope separation method according to the present invention will be described with reference to the drawings.
First Embodiment
The isotope separation apparatus and the isotope separation method according to the first embodiment will be described with reference to FIGS. 1 and 2.

(Overview)
First, an overview of the isotope separation apparatus and the isotope separation method according to the present embodiment will be described with reference to FIG.

When a liquid containing heavy water (D ₂ O) or tritiated water (HTO, DTO, T ₂ O, etc.) is misted, the mist containing much heavy water or tritiated water is more than the mist containing mainly light water (H ₂ O) The density also increases. The separation system by mist formation separates heavy water and tritiated water by this density difference.

  Furthermore, the present inventors place packings or structures (partitioning members) in the separating apparatus, and actively cause aggregation and dropletization of the mist to improve the separation efficiency of isotopes. The present invention has been found out.

  FIG. 1 is a block diagram of an isotope separation apparatus 20 according to an embodiment of the present invention, which includes a container 1 containing a liquid 1a mainly containing water including isotopes such as heavy water and / or tritium water. A mist forming device 7 for forming a liquid 1 a in the container 1, a pipe 2 for supplying a gas 2 a for transferring the mist, a mist transfer pipe 4 provided on the upper part of the container 1, and a mist transfer pipe 4 It consists of at least one or more partition members 5a installed inside and a mist recovery container 9 connected to the upper part of the mist transfer pipe 4 by piping.

  At least one partition member 5a is provided so that a plurality of regions (in the example of FIG. 1, region I to region III) are formed in the height direction of the mist transfer pipe 4, and in the form of particles having a large number of small holes. An aggregate (granular aggregate), a structure such as a punching metal, a honeycomb metal, a lattice metal, or a sintered body is used. In the example of FIG. 1, the example which uses a granular aggregate as the partition member 5a is shown.

  In addition, the mist formation device 7 is a means for forming mist by spraying of gas or liquid, a pressurizing action due to collision, a means for forming mist by oscillating action by high frequency wave or sound wave, rotation, heating or stirring of the liquid 1a. Although a means for forming a mist or the like is used, the example of FIG. 1 shows an example of forming a mist by spraying or collision of a gas. Although the gas spray device may be provided independently, a transfer gas may be used in combination as the spray means, and the example of FIG. 1 shows an example in which the transfer gas 2a is used in combination as the mist formation means. .

In addition, the gas 2a contains at least one gas of nitrogen, oxygen, argon, helium, neon, carbon dioxide gas, or water vapor.
Furthermore, although the mist formation means mentioned above may be one type, you may use it in combination of multiple types.

The operation of the isotope separator 20 configured as described above will be described.
First, it is assumed that a liquid having an isotope concentration of A (becquerel / ml) is contained in the container 1.

When the liquid 1 a in the container 1 is misted by the pressurizing action of the gas 2 a sprayed from the pipe 2, the mist 3 a flows into the region I of the mist transfer pipe 4.
At that time, when the liquid 1a becomes mist 3a, the surface area becomes large and it is easily volatilized, the surface temperature of the partition member 5a is lowered due to the evaporation latent heat, and a part of the mist 3a is easily aggregated.

  In addition, the inside of the mist transfer pipe 4 may be controlled to a temperature lower than the ambient temperature of the container 1. In that case, mist smaller than the particle diameter of the particulate aggregate constituting the partition member 5a is transferred in the traveling direction On the other hand, the droplet 6 whose particle diameter is increased due to aggregation or the like drops downward.

As described above, the mist 3a attached to the partition member 5a condenses with the other mist 3a to form droplets, and drops toward the container 1 when the gravity of the droplets 6 becomes larger than the adhesion of the partition member 5a.
Further, at least a part of the partition member 5 may be made of a hydrophobic substance or covered with a hydrophobic substance to promote the droplet formation.

In the example shown in FIG. 1, the mist transfer pipe 4 is provided with two partition members 5a consisting of granular aggregates and is divided into three regions I to III. By carrying out the transfer of the mist having a small specific gravity, a mist having a small isotope concentration in each region is generated and transferred to the next region. By repeating this in a plurality of regions, a mist having a lower isotope concentration is finally obtained, and is collected in the mist collection container 9.
In this way, it is possible to separate the liquid containing isotope 1a into a liquid with high isotope concentration and a liquid with small isotope concentration.

Here, the degree of separation F (T) in one region is expressed by equation (1).
F = isotope concentration of liquid in container 1 / isotope concentration in mist ... (1)

Assuming that the isotope concentration of the liquid in the container 1 is A (becquerel / ml), the isotope concentration (Bq / ml) of the mist is represented by the following formulas (2) to (4) in the regions I to III, respectively. Ru.
Region I; A × (1-F (T)) ... (2)
Region II; A × (1-F (T)) ² (3)
Region III; A × (1−F (T)) ³ (4)

The degree of separation F (T) is a function of the temperature T, and when the temperature is around room temperature, the degree of separation F (T) is about 5 to 10%, and by making the separation process into multiple stages (multiple regions), The overall degree of separation can be increased.
In addition, the installation position of the partition member 5a and an installation space | interval can be changed suitably.

Example 1
In the first embodiment, the container 1 shown in FIG. 1 contains a liquid 1a mainly composed of water (H ₂ O) discharged from a nuclear facility. The liquid 1a contains a high concentration of tritium which is an isotope of hydrogen, but in some cases it may contain an ionic component such as Na ⁺ or Cl ⁻ .
In addition, as the existence form of tritium, HTO, DTO, T ₂ O may be mentioned, but it exists mainly in the form of HTO. In addition, isotopes of oxygen may also be included.

In the first embodiment, isotopes of hydrogen or oxygen are separated using the isotope separation device 20 shown in FIG.
First, the gas 2 a from the piping 2 is caused to collide with the gas-liquid interface of the liquid 1 a in the container 1 by spraying, and the mist 3 a is generated in the upper space in the container 1.

The gas 2a contains at least one or more of nitrogen, oxygen, argon, helium, neon, carbon dioxide gas and water vapor, and is maintained at about 50 kPa or more.
The mist 3a generated in the container 1 enters the area I of the mist transfer pipe 4 and ascends in the area I together with the gas 2a. When the mist 3a in the region I contacts the inner surface of the mist transfer pipe 4 and the partition member 5a, the mists 3a are coalesced together, the density is increased, and the liquid droplets are formed. The droplets 6 fall toward the container 1 and are again atomized by the gas 2a.

The evaporation of the mist 3a is promoted by the increase of the surface area, but when it evaporates in the vicinity of the partition member 5a, the surface temperature of the partition member 5a decreases due to the latent heat of evaporation, and dropletization due to aggregation tends to occur. The humidity of the gas 2a is reduced. Then, the evaporation rate increases as the difference between the humidity in the gas 2a and the humidity of the surrounding environment increases, so that evaporation easily occurs on the surface portion of the partition member 5a, and dropletization is promoted.
As described above, in the region I, the mist 3a is actively formed into droplets, while the mist 3b having a small diameter passes through the partition member 5a and enters the region II.

  Then, the same phenomenon as in the region I is repeated in the region II. That is, in the region II, the humidity is lower than that in the region I, and the mist 3b having a small diameter promotes dropletization by aggregation by the partition member 5a or the like between the region II and the region III. The small mist 3c moves to the region III through the partition member 5a.

  Further, in the low humidity region III, dropletization is promoted by evaporation or contact with the inner surface of the mist transfer pipe 4, etc., and the mist 3d having a smaller diameter is finally recovered in the mist recovery container 9 and liquefied by aggregation etc. Be done.

In the example of FIG. 1, the relative humidity in the region I to the region III is expressed as high humidity, medium humidity, and low humidity, respectively.
As described above, in Example 1, as a result of sequentially performing isotope separation in the regions I to III, the isotope concentration in the region III is A × (1−F (T )) ³ ).

A demonstration test was conducted using pure water (H ₂ O) containing 80 Bq / ml tritiated water (HTO) using this isotope separator, and as shown in FIG. It was found that the degree of separation F (T) was maintained at about 10%.

  In the first embodiment, the three-stage mist transfer pipe 4 including the region I to the region III is used. However, the present invention is not limited to this, and the separation efficiency can be further enhanced by increasing the number of stages.

(effect)
As described above, according to the first embodiment, by using the multistage mist transfer pipe 4 partitioned by the partition member 5a, a compact isotope separator and isotope having high isotope separation efficiency are provided. A separation method can be provided.

Second Embodiment
An isotope separator according to a second embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the said embodiment, and the overlapping description is abbreviate | omitted.

  In the second embodiment, as shown in FIG. 3, the region I and the region II are partitioned by the partition member 5a made of a granular aggregate, and the region II and the region III are a plurality of pores. It is divided by the partition member 5b which consists of a structure which it has. The partition members 5a and 5b are connected to the temperature control device 10, and can be cooled to a desired temperature.

The structure constituting the partition member 5b is made of a punching metal, a honeycomb metal, a lattice metal, a sintered body or the like, and a large number of holes through which mist can pass are formed.
The temperature control device 10 cools the partition members 5a and 5b to a temperature lower than the internal temperature of the mist transfer pipe 4, and promotes mist condensation and dehumidification of the gas 2a in the vicinity of the partition members 5a and 5b.

Thereby, the evaporation of the mist adhering to the partition members 5a and 5b is promoted, and the mist collection efficiency can be finally improved.
Incidentally, the structure of the granular aggregate, the punching metal and the like constituting the partition members 5a and 5b is at least a part of a hydrophobic material or is covered with a hydrophobic material to form a mist liquid It may be possible to promote the formation of droplets or the evaporation of mist.

  As described above, according to the second embodiment, by using different types of partition members and connecting them to the temperature control device, it is possible to improve isotope separation efficiency and compactness of the device.

Third Embodiment
An isotope separator according to a third embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the said embodiment, and the overlapping description is abbreviate | omitted.
In the third embodiment, as shown in FIG. 4, the mist transfer pipe 4 is arranged to be inclined with respect to the container 1.

  The mists 3a to 3c in the vicinity of the partition member 5a move laterally on the inclined partition member 5a, so the moving distance of the mists 3a to 3c is longer than that of the mist transfer pipe 4 in the vertical direction. As a result, since the time for the mists 3a to 3c to stay in the vicinity of the partition member 5a becomes long, it is possible to further promote the droplet formation of the mist and the evaporation of the mist.

In addition, since a part of the droplets 6 formed by the aggregation etc. drips onto the container 1 along the inner surface of the mist transfer pipe 4, the direct dripping to the container 1 can be reduced. Thereby, it becomes possible to perform mist formation in container 1 stably.
In addition, the inclination angle of the mist transfer pipe 4 can be changed suitably.

  As described above, according to the third embodiment, it is possible to further improve the separation efficiency of isotopes by inclining the mist transfer pipe 4.

Fourth Embodiment
An isotope separator according to a fourth embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the said embodiment, and the overlapping description is abbreviate | omitted.

  In the fourth embodiment, as shown in FIG. 5, the temperature control device 11 is connected to the mist recovery container 9, and the refrigerant is supplied to the mist recovery container 9, thereby liquefying the mist 3d recovered from the region III. To promote.

  As a result, the recovery rate and recovery efficiency of low concentration isotopes are improved, and the humidity of the gas 2a is reduced. By returning the gas 2 a to the container 1 through the pipe 13 and reusing the gas for mist generation and the gas for transfer in the container 1, it is possible to improve processing efficiency and save resources.

Fifth Embodiment
The isotope separation system according to the fifth embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the said embodiment, and the overlapping description is abbreviate | omitted.
In the fifth embodiment, as shown in FIG. 6, a system configuration in which a plurality of isotope separators 21 to 24 are arranged in parallel and / or in series is used.

In the system example shown in FIG. 6, the isotope separators 21 and 22 described in the first to fourth embodiments are arranged in parallel to perform parallel processing, and thereafter, the isotope separators 23 arranged in series, 24 is configured to perform serial processing. As a result, processing speed can be improved in parallel processing, and separation efficiency can be improved in serial processing.
The system shown in FIG. 6 is only an example, and various systems using a plurality of isotope separation devices can be configured by appropriately combining parallel processing and / or serial processing.

  While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. For example, although tritium has been described as an example in the above embodiment, the present invention is also applicable to isotopes of deuterium and oxygen, and is also applicable to isotopes other than hydrogen and oxygen.

  These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

DESCRIPTION OF SYMBOLS 1 ... Container, 1a ... Liquid, 2 ... Plumbing, 2a ... Gas, 3a-3d ... Mist, 4 ... Mist transfer pipe, 5a, 5b ... Partition member, 6 ... Droplet, 7 ... Mistization apparatus, 9 ... Mist collection Container, 10, 11 ... temperature control device, 13 ... piping, 20-24 ... isotope separation device

Claims (10)

A container containing a liquid containing an isotope, a mist forming apparatus for forming the liquid into a mist, a mist transfer pipe provided on an upper portion of the container, and a partition member dividing the mist transfer pipe into a plurality of regions An isotope separation apparatus comprising: a gas for transferring the mist; and a mist recovery container connected to an upper portion of the mist transfer pipe,
The isotope separation device according to claim 1, wherein the partition member has a large number of holes through which mist can pass.   The isotope separating apparatus according to claim 1, wherein the partition member is a granular aggregate, a sintered body, a punching metal, a honeycomb metal or a lattice metal.   The isotope separation apparatus according to claim 1 or 2, wherein at least a part of the partition member is a hydrophobic substance or is covered with a hydrophobic substance.   The mist forming device is a gas spraying device, a liquid spraying device, a high frequency vibrating device, a rotating device, a sonic vibration device, a pressure reducing device or a heating device, or a combination thereof. The isotope separator according to any one of the above.   5. The isotope separation apparatus according to claim 4, wherein the gas sprayed from the gas spray device includes at least one or more of nitrogen, oxygen, argon, helium, neon, carbon dioxide gas, and water vapor.   The isotope separation apparatus according to any one of claims 1 to 5, wherein the mist transfer pipe is inclined with respect to the container.   The temperature control apparatus is connected to the said mist collection | recovery apparatus and / or the said partition member, The isotope separation apparatus in any one of the Claims 1 thru | or 6 characterized by the above-mentioned.   The isotope separation apparatus according to any one of claims 1 to 7, wherein the mist recovery container and the container are connected by piping, and the gas recovered in the gas recovery container is reused.   9. An isotope separation system comprising a plurality of the isotope separators according to any one of claims 1 to 8 arranged in parallel and / or in series.   An isotope separation method comprising performing isotope separation using the isotope separation device according to any one of claims 1 to 8.

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