JP2011149863A - Nuclide transmutation device and nuclide transmutation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nuclide transmutation device having a simple constitution, capable of increasing a reaction amount of a nuclide transmutation reaction by improving a deuterium density on a structure surface, and to provide a nuclide transmutation method using the device. <P>SOLUTION: This nuclide transmutation device 10 includes: a chamber 11; a deuterium supply part 12 for supplying deuterium to the inside of the chamber 11; a structure 15 arranged inside the chamber 11, and having palladium or a palladium alloy, or a hydrogen absorbing metal other than palladium or a hydrogen absorbing metal other than a palladium alloy, and a material having a work function which is relatively low thereto; and a temperature adjustment part 16 arranged inside the chamber 11, for varying the temperature of the structure 15. A deuterium barrier layer including a material preventing permeation of deuterium is provided on the surface on the arrangement side of the temperature adjustment part 16 of the structure 15, and a material to which nuclide transmutation is applied is added to the surface on the opposite side to the arrangement side of the temperature adjustment part 16 of the structure 15. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention performs nuclide conversion in a radionuclide conversion apparatus and a nuclide conversion method related to radioactive waste processing technology, technology for generating rare elements from elements abundant in nature, energy generation technology by agglomeration nuclear reaction, and the like. The present invention relates to an apparatus and a method for increasing the permeation amount of deuterium gas that permeates through a structure to which a substance to be added is added.

  Patent Document 1 and Patent Document 2 disclose 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. Yes.

  The nuclide conversion device disclosed in the above document includes a structure including a hydrogen storage metal or a hydrogen storage alloy such as palladium (Pd) or a palladium alloy, and a material having a relatively lower work function than these, and the inside is kept airtight. An occlusion chamber made possible, a discharge chamber provided so as to be kept airtight across the structure, deuterium supply means for supplying deuterium gas to the occlusion chamber, and exhaust means for evacuating the discharge chamber Prepare. A substance to be subjected to nuclide conversion is added to one surface of the structure.

  First, after the storage chamber and the discharge chamber are evacuated, the structure is heated to 70 ° C., for example. Thereafter, evacuation of the storage chamber is stopped, and deuterium gas is introduced into the storage chamber. Deuterium gas permeates through the structure due to a pressure difference from the storage chamber to the discharge chamber, but at this time, the nuclide conversion occurs because the substance that is subjected to nuclide conversion is added to the surface of the structure. To do.

Japanese Patent No. 4347261 (paragraphs [0029] to [0033], [0040] to [0041], FIGS. 1 to 3) Japanese Patent No. 4347262 (paragraphs [0029] to [0033], [0040] to [0041], FIGS. 1 to 3)

In the nuclide conversion devices of Patent Document 1 and Patent Document 2, by supplying deuterium gas to the storage chamber and exhausting the discharge chamber, a deuterium concentration gradient is formed between the storage chamber and the discharge chamber with the structure interposed therebetween. Giving. When the concentration gradient is given, the amount of deuterium gas that permeates the structure increases, the deuterium density on the surface of the structure in the storage chamber increases, and the reaction amount increases.
However, in order to maintain sufficient airtightness between the storage chamber and the discharge chamber, a seal is required when sandwiching the structure, and the apparatus configuration is complicated. Furthermore, it is necessary to increase the thickness of the structure so as to withstand the pressure difference between the storage chamber and the discharge chamber.

  The present invention has been made in view of the above problems, has a simple configuration, and can improve the deuterium density on the surface of the structure, thereby increasing the reaction amount of the nuclide conversion reaction, And it aims at providing the nuclide conversion method using the apparatus.

  In order to solve the above problems, a nuclide conversion device according to the present invention includes a chamber, a deuterium supply unit for supplying deuterium into the chamber, and palladium, a palladium alloy, or other than palladium. A hydrogen storage metal other than the hydrogen storage metal or palladium alloy, a structure having a material having a relatively low work function with respect to these, and a temperature adjustment arranged in the chamber to vary the temperature of the structure A deuterium barrier layer containing a substance that does not allow permeation of deuterium is provided on a surface of the structure on the side where the temperature adjusting unit is arranged, and the temperature adjusting unit of the structure is arranged A substance subjected to nuclide conversion is added to the surface opposite to the side.

  In addition, the nuclide conversion method of the present invention includes a structure having palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage metal other than a palladium alloy, and a substance having a relatively low work function. A deuterium barrier layer forming step of forming a deuterium barrier layer containing a substance that does not allow deuterium permeation on one surface, and a surface of the structure opposite to the surface provided with the deuterium barrier layer, After the nuclide conversion part forming step of adding a substance to be subjected to nuclide conversion, the deuterium barrier layer forming step and the nuclide conversion part forming step, the structure is installed in a chamber, and deuterium is placed in the chamber. A deuterium supply step for supplying the temperature of the structure, the palladium, the palladium alloy, a hydrogen storage metal other than the palladium, or the palladium alloy. A deuterium permeation step of allowing the deuterium to permeate into the structure by setting the temperature below the temperature at which the deuterium density in the outer hydrogen storage metal is increased, and the temperature of the structure is the palladium, the palladium alloy And a deuterium discharging step of discharging the deuterium from the inside of the structure by setting the deuterium density in the hydrogen absorbing metal other than palladium or the hydrogen absorbing metal other than the palladium alloy to be lower than the temperature. .

A hydrogen storage metal such as palladium and a hydrogen storage alloy have different deuterium storage amounts, that is, deuterium densities in the hydrogen storage metal and the hydrogen storage alloy, depending on the temperature. The nuclide conversion apparatus and the nuclide conversion method of the present invention utilize the temperature dependence of the deuterium density in the hydrogen storage metal and the hydrogen storage alloy, and use a nuclide conversion apparatus having a simpler configuration than the conventional structure to make the hydrogen storage metal or hydrogen By allowing deuterium to pass through the structure including the storage alloy, the deuterium concentration can be increased in the vicinity of the nuclide conversion substance provided on the structure surface. As a result, the nuclide conversion reaction can be increased.
Further, according to the present invention, unlike in Patent Document 1 and Patent Document 2, the structure is not required to have a strength capable of withstanding the pressure difference because the structure is not sandwiched between the high pressure portion and the low pressure portion. Therefore, the structure can be thinned.

  The nuclide conversion device of the present invention includes a chamber, a deuterium supply unit for supplying deuterium into the chamber, a pressure adjusting unit for changing the pressure inside the chamber, and a palladium or palladium alloy disposed in the chamber. Or a structure having a hydrogen storage metal other than palladium or a hydrogen storage metal other than a palladium alloy, and a substance having a relatively low work function with respect to these metals, A deuterium barrier layer containing a substance that does not allow permeation of hydrogen is provided, and a substance that is subjected to nuclide conversion is added to a surface different from the surface of the structure on which the deuterium barrier layer is provided.

  In the above invention, the pressure adjusting means may be a deuterium exhaust section connected to the chamber and exhausting deuterium in the chamber.

  Further, in the above invention, the pressure adjusting means is connected to the outside of the chamber and is sealed together with the chamber, so that the volume changing portion capable of changing the internal volume and the volume changing portion are accommodated. A container that is airtight inside, a gas supply unit that is connected to the container and supplies gas into the container, and a gas exhaust unit that is connected to the container and exhausts the gas in the container. May be provided.

  The nuclide conversion method of the present invention is a structure having palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage metal other than a palladium alloy, and a substance having a relatively low work function. A deuterium barrier layer forming step of forming a deuterium barrier layer containing a substance that does not allow permeation of deuterium on the surface of the structure, and nuclide conversion on a surface different from the surface on which the deuterium barrier layer of the structure is provided. After the nuclide conversion part forming step of adding a substance to be applied, the deuterium barrier layer forming step, and the nuclide conversion part forming step, the structure is installed in a chamber and deuterium is supplied into the chamber. A deuterium supply step and a deuterium pressure in the chamber, the palladium, the palladium alloy, a hydrogen storage metal other than the palladium, or the palladium alloy. A deuterium permeation step of increasing the deuterium density in the outer hydrogen storage metal to a pressure higher than that to allow the deuterium to permeate into the structure, and deuterium pressure in the chamber with the palladium, A deuterium discharging step of discharging the deuterium from the inside of the structure by reducing to a pressure lower than a pressure at which a deuterium density in the hydrogen storing metal other than the palladium alloy, the palladium or the hydrogen storing metal other than the palladium alloy is reduced; including.

The hydrogen storage metal and the hydrogen storage alloy have different deuterium storage amounts, that is, the deuterium density in the hydrogen storage metal and the hydrogen storage alloy, depending on the pressure. The nuclide conversion apparatus and the nuclide conversion method of the present invention utilize the pressure dependence of the deuterium density, and without providing a release chamber and a storage chamber with different pressures across the structure, a hydrogen storage metal or a hydrogen storage Deuterium can be permeated into the structure including the alloy, and the deuterium concentration can be increased in the vicinity of the nuclide conversion substance provided on the surface of the structure. As a result, the nuclide conversion reaction can be increased.
In the present invention, the structure is not required to have enough strength to withstand the pressure difference. Therefore, the structure can be thinned.

  In the nuclide conversion device, a covering member containing a substance that does not allow permeation of deuterium may be provided on a surface other than the surface of the structure to which the deuterium barrier layer and the substance subjected to the nuclide conversion are added. preferable.

  In the nuclide conversion method, a covering member containing a substance that does not allow permeation of the deuterium is provided on a surface other than the surface of the structure to which the deuterium barrier layer and the substance subjected to the nuclide conversion are added. It is preferable to further include a covering member forming step.

  Thus, when a deuterium barrier layer containing a substance that does not allow deuterium permeation is provided on a surface other than the surface to which the substance subjected to nuclide conversion is added, the substance that is subjected to nuclide conversion Deuterium permeates into the structure only from the surface to which is added. As a result, it is possible to further improve the nuclide conversion reaction efficiency.

  The present invention can increase the concentration of deuterium in the vicinity of the surface of a structure to which a substance that performs nuclide conversion is added by allowing deuterium to permeate into the structure by an apparatus having a simple configuration. As a result, the nuclide conversion reaction can be increased.

1 is a schematic view of a nuclide conversion apparatus according to a first embodiment. The cross-sectional schematic of an example of a structure is shown. The cross-sectional schematic of another example of a structure is shown. It is a graph showing the relationship between the temperature of a structure, and the hydrogen density in Pd in each structure pressure. It is a graph showing the relationship between the pressure inside a chamber, and the hydrogen density in Pd in each structure temperature. It is the schematic of the nuclide conversion apparatus which concerns on 3rd Embodiment.

<First Embodiment>
FIG. 1 is a schematic diagram of a nuclide conversion apparatus according to the first embodiment. The nuclide conversion apparatus 10 includes a chamber 11 whose inside is hermetically sealed, and a deuterium supply unit 12 connected to the chamber 11. The deuterium supply unit 12 includes a deuterium cylinder 13 and valves 14 </ b> A and 14 </ b> B disposed between the chamber 11 and the deuterium cylinder 13.
Inside the chamber 11, a structure 15 and a temperature adjustment unit 16 are arranged. The chamber 11 is connected to a chamber exhaust unit 17 for exhausting the inside of the chamber 11. The chamber exhaust unit 17 is, for example, a turbo molecular pump 18 and a rotary pump 19, and a valve 20 provided between the chamber 11 and the turbo molecular pump 18.

  FIG. 2 shows a schematic cross-sectional view of an example of the structure. The structure is composed of palladium (Pd) or a Pd alloy, or a hydrogen storage metal other than Pd (such as Ti) or an alloy thereof, and a substance having a relatively low work function. Specifically, in the plate-like structure 15A shown in FIG. 2, a substance having a work function relatively low with respect to Pd (for example, CaO) and Pd are alternately stacked on the surface of the Pd substrate 21. The mixed layer 22 is formed, and the Pd layer 23 is formed on the surface of the mixed layer 22. In the mixed layer 22, for example, a total of eight layers of CaO and Pd are alternately stacked in order from the Pd substrate 21 side, and CaO is formed on the uppermost layer.

  A substance to be subjected to nuclide conversion is added to the surface of the Pd layer 23 to form a nuclide conversion unit 24. Examples of the substance subjected to nuclide conversion include cesium (Cs), carbon (C), strontium (Sr), sodium (Na), and the like. As a method of adding a substance to be subjected to nuclide conversion to the surface of the Pd layer 23, a method of laminating a substance to be subjected to nuclide conversion on the surface of the Pd layer 23 and a substance to be subjected to nuclide conversion on the surface of the Pd layer 23 are included. And a method of exposing to deuterium.

A deuterium barrier layer 25 containing a substance that does not allow permeation of deuterium is provided on the surface of the Pd substrate 21 opposite to the surface on which the mixed layer 22 is provided. Examples of substances that do not allow deuterium permeation include copper (Cu), gold (Au), silicon (Si), stainless steel (SUS304, SUS316L, etc.), oxidized iron (Fe), and SiO ₂ . The deuterium barrier layer 25 may be formed on the surface of the Pd substrate 21 by a known method, or may be a substrate-like one adhered to the Pd substrate 21.

  FIG. 3 shows a schematic cross-sectional view of another example of the structure. In the structure 15B of FIG. 3, a mixed layer 22 in which Pd and CaO are alternately stacked is formed on the surface of the deuterium barrier layer 25 having a flat plate shape, and a Pd layer 23 is formed on the surface of the mixed layer 22. Is done. The nuclide conversion part 24 is formed on the surface of the Pd layer 23 as described above.

  As shown in FIGS. 2 and 3, a covering member 26 can be provided on the surface (side surface) of the structures 15 </ b> A and 15 </ b> B where the nuclide conversion part 24 and the deuterium barrier layer 25 are not provided. The covering member 26 is a jig or the like, and includes the above-described substance that does not allow permeation of deuterium. The covering member 26 may cover a part of the nuclide conversion unit 24 and the deuterium barrier layer 25 as shown in FIGS.

  The structure 15 is disposed in the chamber 11 such that the deuterium barrier layer faces the temperature adjustment unit 16. The structure 15 and the temperature adjustment unit 16 may be in contact with each other, or may be arranged apart from each other by a distance capable of transferring heat from the temperature adjustment unit 16 to the structure 15.

  The temperature adjustment unit 16 is a heating device such as a heater. Alternatively, a combination of a heating device and a cooling device may be used.

A method for performing nuclide conversion using the nuclide conversion apparatus of the first embodiment will be described with reference to FIG.
After the structure 15 is disposed on the temperature adjustment unit 16 in the chamber 11, the piping valve 20 that connects the pumps 18 and 19 and the chamber 11 is opened. Thus, the chamber 11 is evacuated by the chamber exhaust means 17.

When the inside of the chamber is sufficiently evacuated (for example, 0.1 Pa or less, preferably 1 × 10 ⁻⁴ Pa or less), the valve 20 of the pipe connecting the pump 18.19 and the chamber 11 is closed. Next, the temperature adjusting unit 16 controls and holds the temperature of the structure 15 so that the deuterium density in the hydrogen storage metal or the hydrogen storage alloy is not higher than the temperature.

After the temperature of the structure 15 is controlled, the valves 14A and 14B of piping connecting the deuterium cylinder 13 and the chamber 11 are opened, and deuterium is introduced into the chamber 11 from the cylinder 13.
FIG. 4 is a graph showing the relationship between the temperature of the structure and the hydrogen density in Pd at each structure pressure. In the figure, the horizontal axis represents the temperature of the structure, and the vertical axis represents the hydrogen density in Pd. Note that the hydrogen density in FIG. 4 can be read as deuterium density.
According to FIG. 4, at the same pressure, the deuterium density in Pd tends to increase as the temperature increases. At each pressure, there is a temperature at which the deuterium density in Pd changes abruptly.

  Based on the graph illustrated in FIG. 4, the temperature at which the structure is held is appropriately set in consideration of the pressure inside the chamber 11 and the temperature at which the deuterium density in Pd changes rapidly. That is, in order to stably transmit deuterium, the temperature of the structure is set to a value smaller than the temperature at which the deuterium density in Pd changes rapidly. For example, in the case of 0.5 atm, 120 ° C. or less, and in the case of 1 atm, 140 ° C. or less.

When the deuterium density in the hydrogen storage metal or hydrogen storage alloy is set to a temperature lower than that at a predetermined pressure, deuterium permeates from the surface of the structure 15 toward the inside. When deuterium permeates the nuclide conversion unit 24, a nuclide conversion reaction occurs. At this time, since the deuterium density on the surface of the nuclide conversion unit 24 is higher than the deuterium density inside the structure, the nuclide conversion reaction is promoted.
Note that deuterium does not enter the structure 15 from the deuterium barrier layer 25 side. Further, by providing the covering member 26 as shown in FIGS. 2 and 3, deuterium intrusion from the side surface of the structure 15 is prevented. For this reason, since deuterium can be transmitted only through the nuclide conversion unit 24, the nuclide conversion efficiency is improved.

When the amount of deuterium in the structure 15 reaches a saturated state, the permeation rate of deuterium into the structure 15 decreases, and the nuclide conversion reaction efficiency also decreases.
When the deuterium permeation rate into the structure 15 becomes a predetermined value or less, the temperature adjusting unit 16 adjusts the temperature of the structure 15 so that the deuterium density in the hydrogen storage metal or the hydrogen storage alloy is equal to or higher than the low temperature. Control and hold. The temperature at this time is appropriately set according to the pressure inside the chamber 11 based on the graph illustrated in FIG. For example, in the case of 0.5 atm, the temperature is 130 ° C. or more, and in the case of 1 atm, the temperature is 155 ° C. or more. In this case, since the density of deuterium stored in the structure 15 is lowered, deuterium is released from the structure 15 through a portion where the deuterium barrier layer and the covering member are not provided.

When the amount of deuterium in the structure 15 is sufficiently released and the deuterium release rate is equal to or lower than a predetermined value, the temperature adjusting unit 16 sets the temperature of the structure 15 to the deuterium density in the hydrogen storage metal or hydrogen storage alloy. Control and maintain the temperature to be lower than the rising temperature. By doing so, a nuclide conversion reaction occurs when passing through the nuclide conversion part.
By repeating the above structure temperature control, the nuclide conversion reaction can be continued with high efficiency.

  The deuterium permeation rate and deuterium release rate are calculated based on the deuterium diffusion rate, temperature, and film thickness of each layer of the structure. Based on the calculated deuterium permeation rate and deuterium release rate, a time for maintaining the deuterium density in the structure at a high temperature and a time for maintaining the deuterium density at a low temperature are set.

Second Embodiment
As a second embodiment, a method for performing nuclide conversion using a nuclide conversion apparatus having the same configuration as that of FIG. 1 will be described. In the present embodiment, a structure similar to that shown in FIGS. 2 and 3 can be used.

  After the structure 15 is disposed on the temperature adjustment unit 16 in the chamber 11, the piping valve 20 connecting the pumps 18 and 19 and the chamber 11 is opened, and the chamber exhaust unit 17 evacuates the interior of the chamber 11. Is done.

When the inside of the chamber 11 is sufficiently exhausted (for example, 0.1 Pa or less, preferably 1 × 10 ⁻⁴ Pa or less), the valve 20 of the pipe connecting the pumps 18 and 19 and the chamber 11 is closed. Next, the structure 15 is controlled and held at a predetermined temperature by the temperature adjusting unit 16.

  When the temperature of the structure 15 is maintained at a predetermined temperature, the valves 14A and 14B of the pipe connecting the cylinder 13 and the chamber 11 are opened, and deuterium is introduced into the chamber 11 from the cylinder 13. The deuterium supply unit 12 controls and holds the deuterium pressure in the chamber 11 so that the deuterium density in the hydrogen storage metal or hydrogen storage alloy becomes equal to or higher than the pressure.

FIG. 5 shows a graph showing the relationship between the pressure inside the chamber and the hydrogen density in Pd at each structure temperature. In the figure, the horizontal axis represents the hydrogen density in Pd, and the vertical axis represents the pressure. Note that the hydrogen density in FIG. 5 can be read as deuterium density.
According to FIG. 5, the deuterium density in Pd is low when the pressure in the chamber is low, and the deuterium density in Pd tends to be high when the pressure in the chamber is high. In addition, there is a pressure at which the deuterium density in Pd changes abruptly at each structure temperature.

  The holding pressure inside the chamber 11 is appropriately set based on the graph illustrated in FIG. 5 in consideration of the holding temperature of the structure 15 and the pressure at which the deuterium density in Pd changes rapidly. That is, in order to allow deuterium to pass through stably, the pressure inside the chamber 11 is set to a value larger than the pressure at which the deuterium density in Pd changes rapidly. Specifically, for example, when the temperature of the structure is 70 ° C., the pressure is 0.1 atmosphere or more, and when it is 120 ° C., the pressure is 1 atmosphere or more.

When the deuterium pressure in the chamber 11 is set to a value that increases the deuterium in Pd, deuterium permeates from the surface of the structure 15 toward the inside. When deuterium permeates the nuclide conversion unit 24, a nuclide conversion reaction occurs. At this time, since the deuterium density on the surface of the nuclide conversion unit 24 is higher than the deuterium density inside the structure, the nuclide conversion reaction is promoted.
Note that deuterium does not enter the structure 15 from the deuterium barrier layer 25 side. Further, by providing the covering member 26 as shown in FIGS. 2 and 3, deuterium intrusion from the side surface of the structure 15 is prevented. For this reason, since deuterium can be transmitted only through the nuclide conversion unit 24, the nuclide conversion efficiency is improved.

As described above, when the amount of deuterium in the structure 15 is saturated and the deuterium permeation rate into the structure 15 becomes a predetermined value or less, the valve 14A for piping connecting the deuterium cylinder 13 and the chamber 11 is used. , 14B are closed. Subsequently, the valve 20 of the pipe connecting the pumps 18 and 19 and the chamber 11 is opened, and the chamber exhaust unit 17 discharges deuterium inside the chamber 11.
When the pressure in the chamber 11 reaches a pressure at which the deuterium density in Pd becomes low, the deuterium occluded in the structure 15 passes through a portion where the deuterium barrier layer and the covering member are not provided. Released to the outside of the structure.

  When the deuterium in the structure 15 is sufficiently released and the deuterium release speed becomes a predetermined value or less, the valve 20 of the pipe connecting the cylinders 18 and 19 and the chamber 11 is closed. Next, the valves 14 A and 14 B of the pipe connecting the deuterium cylinder 13 and the chamber 11 are opened, and deuterium is supplied again into the chamber 11.

  The deuterium permeation rate and deuterium release rate are calculated based on the deuterium diffusion rate, temperature, deuterium pressure, and the thickness of each layer of the structure. Based on the calculated deuterium permeation rate and deuterium release rate, the time for supplying deuterium and the time for discharging deuterium are set.

<Third Embodiment>
FIG. 6 is a schematic diagram of a nuclide conversion apparatus according to the third embodiment. The nuclide conversion device 30 includes a chamber 31 whose inside is hermetically sealed, a deuterium supply unit 32 connected to the chamber 31, a volume changing unit 41 connected integrally with the chamber 31 outside the chamber 31, And a container 42 provided so as to accommodate the volume changing unit 41. The deuterium supply unit 32 includes a deuterium cylinder 33 and valves 34 </ b> A and 34 </ b> B disposed between the chamber 31 and the cylinder 33.

  Inside the chamber 31, a structure 35 and a temperature adjustment unit 36 are arranged. In the present embodiment, a structure similar to that shown in FIGS. 2 and 3 can be used. A chamber exhaust unit 37 is connected to the chamber 31 in order to exhaust the interior of the chamber 31. The chamber exhaust part 37 is, for example, a turbo molecular pump 38 and a rotary pump 39, and a valve 40 provided between the chamber 31 and the turbo molecular pump 38.

  A gas supply unit 43 that supplies gas into the container 42 and a gas exhaust unit 46 that discharges gas inside the container 42 are connected to the container 42. The gas supply unit 43 includes a cylinder 44 and valves 45 </ b> A and 45 </ b> B disposed between the container 42 and the cylinder 44. The gas exhaust unit 46 is a valve in FIG. 6, but a pump such as a rotary pump or a turbo molecular pump may be further connected to the downstream side of the valve.

  The volume changing unit 41 is airtight with the chamber 31. The volume changing unit 41 can change its internal volume. Specifically, the volume variation part 41 has a bellows shape.

A method for performing nuclide conversion using the nuclide conversion apparatus of the third embodiment will be described with reference to FIG.
After the structure 34 is disposed on the temperature adjustment unit 36 in the chamber 31, the piping valve 40 that connects the pumps 38 and 39 and the chamber 31 is opened. By doing so, the inside of the chamber 31 is evacuated by the chamber exhaust unit 37.

When the inside of the chamber 31 is sufficiently exhausted (for example, 0.1 Pa or less, preferably 1 × 10 ⁻⁴ Pa or less), the valve 40 of the pipe connecting the pumps 38 and 39 and the chamber 31 is closed. Next, the structure 35 is controlled and held at a predetermined temperature by the temperature adjusting unit 36.

The gas supply unit 43 supplies gas into the container 42 so that the valves 45A and 45B of the pipe connecting the container 42 and the cylinder 44 are opened and the volume of the volume changing unit 41 is minimized. The gas applied to this embodiment is not particularly limited, but air or nitrogen is preferable in consideration of safety and cost. At this time, the gas exhaust part 46 (valve) is closed.
When the volume of the volume changing unit 41 becomes minimum and the pressure inside the container 42 reaches a predetermined value, the gas supply unit 43 stops supplying gas. The pressure inside the container 42 may be set higher than the pressure reached when deuterium is supplied into the chamber 31 in the subsequent stage. Alternatively, the gas supply unit 43 may continue to supply gas even during the subsequent deuterium supply so that the pressure inside the container 42 is always higher than the pressure inside the chamber 31 and the volume changing unit 41.

  Next, the valves 34 A and 34 B of piping connecting the deuterium cylinder 33 and the chamber 31 are opened, and deuterium is introduced into the chamber 31 from the cylinder 33. The deuterium supply unit 32 controls and holds the pressure inside the chamber 31 and the volume variation unit 41 so that the deuterium density in the hydrogen storage metal or the hydrogen storage alloy becomes higher than the pressure. The pressure is set in the same manner as in the second embodiment. By doing so, deuterium permeates from the surface of the structure 35 toward the inside. When deuterium permeates through the nuclide conversion part provided on the structure surface, a nuclide conversion reaction occurs.

  When the amount of deuterium in the structure 35 is saturated and the deuterium permeation rate into the structure 35 becomes a predetermined value or less, the valves 34A and 34B of the pipes connecting the deuterium cylinder 33 and the chamber 31 are closed. The When the gas supply unit 43 continues to supply gas to the container 42, the valves 45A and 45B of the piping connecting the cylinder 44 and the container 42 are closed.

  Next, the gas discharge part 46 (valve) is opened. Thereby, the gas discharge part 46 discharges | emits the gas inside the container 42, and the pressure inside the container 42 falls. When the pressure inside the container 42 becomes lower than the pressure inside the chamber 31 and the volume variation unit 41, the volume variation unit 41 expands, and the pressure inside the chamber 31 and the volume variation unit 41 decreases. When the pressure in the chamber 31 and the volume changing unit 41 reaches a pressure at which the deuterium density in Pd is lowered, the deuterium occluded in the structure 35 is not provided with the deuterium barrier layer or the covering member. It passes through the portion and is released to the outside of the structure 35.

When the deuterium in the structure 35 is sufficiently released and the deuterium release rate becomes a predetermined value or less, the gas discharge part 46 (valve) is closed. Next, the valves 45 </ b> A and 45 </ b> B of the pipe connecting the cylinder 44 and the container 42 are opened, and gas is supplied to the container 42. As a result, the volume changing unit 41 contracts, the pressure inside the chamber 31 and the volume changing unit 41 rises, and deuterium permeation into the structure 35 is resumed. In order to supplement the deuterium consumed by the previous nuclide conversion reaction, the valves 34A and 34B of the pipe connecting the deuterium cylinder 33 and the chamber 31 are opened, and deuterium is supplied into the chamber 31. Also good.
By repeating the above control, the nuclide conversion reaction is continued with high efficiency. The time for supplying deuterium and the time for discharging gas from the container are set based on the deuterium permeation rate and the deuterium release rate, respectively, as in the second embodiment.

DESCRIPTION OF SYMBOLS 10,30 Nuclide conversion apparatus 11,31 Chamber 12,32 Deuterium supply part 15,35 Structure 16,36 Temperature adjustment part 17,37 Chamber exhaust part 21 Pd substrate 22 Mixed layer 23 Pd layer 24 Nuclide conversion part 25 Deuterium Barrier layer 41 Volume variation part 42 Container 43 Gas supply part 46 Gas discharge part

Claims (8)

A chamber;
A deuterium supply section for supplying deuterium into the chamber;
A structure that is disposed inside the chamber and includes palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage metal other than a palladium alloy, and a material having a relatively low work function with respect to these,
A temperature adjusting unit arranged in the chamber and changing the temperature of the structure;
With
A deuterium barrier layer containing a substance that does not allow permeation of deuterium is provided on the surface of the structure on the side where the temperature adjustment unit is disposed,
A substance to be subjected to nuclide conversion is added to the surface of the structure opposite to the side on which the temperature adjusting unit is disposed.
Nuclide conversion device. A chamber;
A deuterium supply section for supplying deuterium into the chamber;
A pressure adjusting unit for changing the pressure inside the chamber;
A structure that is disposed in the chamber and includes palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage metal other than a palladium alloy, and a material having a relatively low work function with respect to these,
With
A deuterium barrier layer containing a substance that does not allow permeation of deuterium is provided on one surface of the structure,
A substance subjected to nuclide conversion is added to a surface different from the surface on which the deuterium barrier layer of the structure is provided,
Nuclide conversion device.   The nuclide conversion apparatus according to claim 2, wherein the pressure adjusting unit is a deuterium exhaust unit that is connected to the chamber and exhausts deuterium in the chamber. The pressure adjusting means is
A volume changing unit connected to the outside of the chamber and sealed together with the chamber, and the volume of the inside can be changed;
A container which is provided so as to accommodate the volume changing portion and is internally airtight;
A gas supply means connected to the container for supplying gas into the container;
A gas exhaust unit connected to the container and exhausting the gas in the container;
The nuclide conversion device according to claim 2 provided with.   The covering member containing the substance which does not permeate deuterium is provided on the surface of the structure other than the surface to which the deuterium barrier layer and the substance subjected to the nuclide conversion are added. The nuclide conversion apparatus of any one of Claims. Deuterium permeates through one surface of a structure having palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage metal other than palladium alloy, and a material having a relatively low work function. A deuterium barrier layer forming step of forming a deuterium barrier layer containing a substance that is not allowed to occur;
A nuclide conversion part forming step of adding a substance to be subjected to nuclide conversion to the surface opposite to the surface on which the deuterium barrier layer of the structure is provided;
After the deuterium barrier layer forming step and the nuclide conversion unit forming step, the structure is installed in a chamber, and a deuterium supplying step for supplying deuterium into the chamber;
The temperature of the structure is set to be equal to or lower than a temperature at which deuterium density in the palladium, the palladium alloy, the hydrogen storage metal other than palladium, or the hydrogen storage metal other than the palladium alloy is increased, and the structure is brought into the structure. A deuterium permeation step for permeating the deuterium;
The temperature of the structure is set to be equal to or higher than the temperature at which the deuterium density in the palladium, the palladium alloy, the hydrogen storage metal other than the palladium, or the hydrogen storage metal other than the palladium alloy is reduced, from the inside of the structure. A deuterium discharging step for discharging the deuterium;
Nuclide conversion method including Deuterium permeates through one surface of a structure having palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage metal other than palladium alloy, and a material having a relatively low work function. A deuterium barrier layer forming step of forming a deuterium barrier layer containing a substance that is not allowed to occur;
A nuclide conversion part forming step of adding a substance subjected to nuclide conversion to a surface different from the surface on which the deuterium barrier layer of the structure is provided;
After the deuterium barrier layer forming step and the nuclide conversion unit forming step, the structure is installed in a chamber, and a deuterium supplying step for supplying deuterium into the chamber;
The deuterium pressure in the chamber is increased to a pressure higher than the pressure at which deuterium density in the palladium, the palladium alloy, the hydrogen storage metal other than palladium, or the hydrogen storage metal other than the palladium alloy is increased, and the structure A deuterium permeation step for permeating the deuterium into the interior;
Reducing the deuterium pressure in the chamber below the pressure at which deuterium density in the palladium, palladium alloy, hydrogen storage metal other than palladium, or hydrogen storage metal other than palladium alloy is reduced, and the structure A deuterium discharging step for discharging the deuterium from the inside;
Nuclide conversion method including   The method further includes a covering member forming step of providing a covering member containing a substance that does not allow permeation of the deuterium on a surface other than the surface to which the deuterium barrier layer of the structure and the substance subjected to the nuclide conversion are added. The nuclide conversion method according to claim 6 or 7.

Images