JP2005292152A - Contact device for substance to be nuclide-transformed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact device for a substance to be transformed where nuclides are transformed with a relatively small-scale device. <P>SOLUTION: The contact device is placed in a nuclear transformation device 10 where deuterium is run from the side of one surface 11A of a structure 11 to the side of the other surface 11B of it to a substance 14 to be nuclide-transformed which is put into contact with the one surface 11A of the structure 11 that has palladium or palladium alloy or hydrogen occluding metal other than palladium or that other than palladium alloy and a substance of a low work function. The contact device puts the substance 14 to be nuclide-transformed into contact with the one surface 11A of the structure 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nuclide used in a nuclide conversion apparatus and a nuclide conversion method, for example, an annihilation process for converting long-lived radioactive waste to a short-lived nuclide or a stable nuclide, and a technique for generating a rare element from abundant elements in nature. The present invention relates to a conversion substance contact device.

  Conventionally, for example, a large amount of long-lived radionuclide contained in high-level radioactive waste is compared with a method for nuclide conversion of a small amount of nuclide such as heavy element synthesis by a nuclear fusion reaction using a heavy ion accelerator. A so-called annihilation process is known as a method for efficiently and effectively converting nuclides within a short time. The annihilation process includes minor actinides such as NP, Am, and Cm contained in high-level radioactive waste, long-lived fission products such as Tc-99 and I-129, exothermic Sr-90, Cs- After separating useful platinum group elements such as 137, Rh, and Pd according to the characteristics of each element (group separation), the minor actinides and fission products having a long half-life are irradiated with neutrons, etc. This is a nuclide conversion process that generates a nuclear reaction and converts it into short-lived or non-radioactive nuclides. Useful elements are effectively separated by separating and recovering useful elements and long-lived radionuclides contained in high-level radioactive waste. In addition, the long-lived radionuclide is converted to a short-lived or stable nuclide.

  In the annihilation process, actinides and other annihilation processes by neutron irradiation in nuclear reactors such as fast breeder reactors and actinoid mono-fired furnaces, actinide and other nuclear fragmentation processes by proton irradiation in accelerators, and cesium by gamma irradiation in accelerators, for example, Three types of methods are known, including annihilation of strontium and the like. Neutron irradiation in nuclear reactors, etc. can rationally process minor actinides with large neutron reaction cross sections, and in particular, direct nuclear fission of transuranium elements that are unlikely to undergo fission by irradiating fast neutrons. be able to. However, an annihilation process using an accelerator is applied to long-lived fission products that are difficult to disappear by neutron irradiation such as a nuclear reactor, such as Sr-90 and Cs-137 having small neutron reaction cross sections.

  Unlike the nuclear reactor, the annihilation process using an accelerator can be operated subcritically, so it has advantages such as excellent safety related to criticality and a large degree of freedom in design. Proton accelerator and electron beam accelerator are used. Is done. In the annihilation process using a proton accelerator, for example, a nuclear spallation reaction is performed in which high-energy protons of about 500 MeV to 2 GeV are irradiated to disrupt target nuclei. A large number of neutrons generated by nuclear fragmentation are injected into a subcritical blanket around the target nucleus to generate a fission reaction, or a nuclide conversion reaction is generated by a neutron capture reaction. As a result, for example, transuranium elements such as neptunium and americium and long-lived fission products can be extinguished, and the heat generated by the subcritical blanket can be recovered to generate electricity, which is necessary for the operation of the proton accelerator. Can be self-sufficient.

  In addition, in the annihilation process using an electron beam accelerator, for example, a gamma ray generated by bremsstrahlung of an electron beam, a photonuclear reaction caused by, for example, a gamma ray generated by inverse Compton scattering by combining an electron storage ring and an optical cavity, for example ( For example, long-lived fission products such as strontium and cesium, transuranium elements, and the like are annihilated by utilizing giant resonance such as γ, N) reaction or (γ, fission) reaction.

By the way, when performing nuclide conversion using a nuclear reactor or accelerator as in the case of the annihilation process according to the above-described prior art, a large and expensive device must be used, and the cost required for nuclide conversion increases. There is. Moreover, for example, when processing Cs-137, which is a long-lived fission product, necessary when converting Cs-137 released from a nuclear power plant of about 1 million KW into other nuclides using an accelerator. A large amount of electric power reaches several million KW, which requires a high-intensity and high-current accelerator, which is inefficient.

For example, in a nuclear reactor such as a light water reactor, the thermal neutron flux is about 1 × 10 ¹⁴ / cm ² / sec, whereas the neutron flux necessary for the nuclide conversion of Cs-137 having a small neutron reaction cross section is 1 × There is a problem that the required neutron flux cannot be obtained because it is about 10 ¹⁷ to 1 × 10 ¹⁸ / cm ² / sec. The present invention has been made in view of the above circumstances, for example, a nuclide conversion apparatus and a nuclide conversion capable of performing nuclide conversion with a relatively small apparatus as compared with a large apparatus such as an accelerator or a nuclear reactor. An object of the present invention is to provide a nuclide conversion substance contact device used in the method.

In order to solve the above problems and achieve the object, a nuclide conversion device related to the present invention is a structure made of palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than a palladium alloy ( The structure 11, the multilayer structure 32, the cathode 72, the multilayer structure 89, and the multilayer structure 102) in the embodiment are disposed so as to sandwich the structure from both sides, and can be sealed by the structure. An occlusion part (occlusion chamber 31 or occlusion container 103 or electrolysis cell 83 in the embodiment) and an emission part (emission chamber 34 or emission container 101 or vacuum container 85 in the embodiment) forming a space, and the structure The pressure-increasing means (the deuterium cylinder 35 or the deuterium cylinder 106 in the embodiment or the deuterium cylinder 106 or the The pressure reducing means (the turbo molecular pumps 38, 110 in the embodiment) which makes the pressure of the deuterium relatively low between the source 81) and the discharge portion side which is the other surface side of the structure. And rotary pumps 39, 111 or vacuum exhaust pump 91), and a conversion substance contact means for bringing a substance ( ¹³³ Cs, ¹² C, ²³ Na in the embodiment) that performs nuclide conversion into contact with one surface of the structure (Step S04 or Step S22 or Step S44 or Step S04a in the embodiment).

  According to the nuclide conversion device having the above-described configuration, the nuclide conversion substance is brought into contact with one surface of the structure having a multilayer structure between the one surface side and the other surface side of the structure. By creating a deuterium pressure difference in the structure and generating a deuterium flux from one surface side to the other surface side inside the structure, The nuclide conversion reaction can be generated with good reproducibility.

  Further, in the nuclide conversion apparatus according to the present invention, the high pressure means includes deuterium supply means (deuterium cylinders 35 and 106 in the embodiment) for supplying deuterium gas to the occlusion unit, The means is provided with exhaust means (the turbo molecular pumps 38 and 110 and the rotary pumps 39 and 111 in the embodiment) for evacuating the discharge part.

  According to the nuclide conversion device having the above-described configuration, a pressure difference of deuterium can be formed in the structure by pressurizing the occlusion unit by the deuterium supply unit and reducing the discharge unit to a vacuum state by the exhaust unit. .

  Further, in the nuclide conversion device according to the present invention, the high pressure means supplies the electrolytic solution containing deuterium (electrolytic solution 84 in the embodiment) to the occlusion unit and uses the structure as a cathode to perform the electrolysis. Electrolysis means for electrolyzing the solution (power supply 81 in the embodiment), and the low pressure means includes exhaust means (evacuation pump 91 in the embodiment) for evacuating the discharge section. It is characterized by being.

  According to the nuclide conversion device having the above-described structure, deuterium can be occluded in the structure with an effective large pressure by electrolyzing the electrolytic solution on one surface side of the structure using the structure as a cathode, Furthermore, the pressure difference of deuterium can be formed in the structure by depressurizing the discharge portion to a vacuum state by the exhaust means.

  Furthermore, in the nuclide conversion apparatus according to the present invention, the conversion substance contact means is a conversion substance stacking means for stacking a substance to be subjected to the nuclide conversion on one surface of the structure (step S04 in the embodiment or Step S44 or step S04a) is provided.

  According to the nuclide conversion device having the above-described configuration, a substance that performs nuclide conversion can be stacked on one surface of the structure by a conversion material stacking means, for example, a film forming process such as electrodeposition, vapor deposition, and sputtering.

  Further, in the nuclide conversion device according to the present invention, the conversion substance contact means supplies the substance that performs the nuclide conversion to the occlusion unit, and includes a gas that includes the substance that performs the nuclide conversion on one surface of the structure. Alternatively, a conversion substance supply means (step S22 in the embodiment) for exposure to a liquid is provided.

  According to the nuclide conversion device having the above configuration, for example, a substance that performs nuclide conversion can be brought into contact with one surface of the structure by mixing a substance that performs nuclide conversion into a gas or liquid containing deuterium.

  Further, in the nuclide conversion device according to the present invention, the structure is directed to the one surface side from the other surface side, and sequentially, palladium, palladium alloy, hydrogen storage metal other than palladium, or hydrogen other than palladium alloy. A base material made of a storage alloy (Pd substrate 23 in the embodiment), palladium, a palladium alloy, a hydrogen storage metal other than palladium, or a hydrogen storage alloy other than a palladium alloy, and these A mixed layer (mixed layer 22 in the embodiment) composed of a material having a relatively low work function (CaO in the embodiment) and palladium or a palladium alloy formed on the surface of the mixed layer Alternatively, a surface layer (Pd layer 21 in the embodiment) made of a hydrogen storage metal other than palladium or a hydrogen storage alloy other than palladium alloy. Is characterized by Ete is configured.

  According to the nuclide conversion device having the above-described configuration, the reproducibility of the occurrence of the nuclide conversion reaction can be improved by providing a mixed layer including a substance having a low work function in the structure having a multilayer structure.

  In addition, the nuclide conversion method related to the present invention includes a structure made of palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than a palladium alloy (structure 11 in the embodiment, multilayer structure). 32, the cathode 72, the multilayer structure 89, and the multilayer structure 102), a high pressure treatment (steps in the embodiment) in which one surface side of the structure is in a relatively high deuterium pressure state. S07 or step S25 or step S46), and a pressure reduction process (step S05 or step S23 or step S45 in the embodiment) for making the other surface side of the structure relatively low in deuterium pressure, , A conversion substance contact treatment in which a substance that performs nuclide conversion is brought into contact with one surface of the structure (step S04 or step S22 in the embodiment or It is characterized in that it comprises a step S44 or step S04a).

  According to the nuclide conversion method as described above, in a state where a substance that performs nuclide conversion is brought into contact with one surface of a structure having a multilayer structure, the one surface side and the other surface side of the structure A deuterium pressure difference is provided between the deuterium and the nuclide-converting substance by generating a deuterium flux from one surface side to the other surface side within the structure. Thus, the nuclide conversion reaction can be generated with high reproducibility.

  Further, in the nuclide conversion method according to the present invention, the conversion substance contact treatment includes a conversion substance stacking process (step S04 in the embodiment or step S4) in which a substance to be subjected to the nuclide conversion is stacked on one surface of the structure. Step S44 or step S04a), or any one of the conversion substance supply process (step S22 in the embodiment) in which one surface of the structure is exposed to a gas or liquid containing the substance that performs the nuclide conversion. It is characterized by including.

  According to the nuclide conversion method as described above, a substance to be subjected to nuclide conversion is laminated on one surface of the structure by a conversion substance laminating process, for example, a film forming process such as electrodeposition, vapor deposition, sputtering, or the like. By mixing a substance that performs nuclide conversion into a gas or liquid containing hydrogen, the substance that performs nuclide conversion can be brought into contact with one surface of the structure.

  Furthermore, in the nuclide conversion method according to the present invention, the conversion substance contact treatment is characterized in that a substance to be subjected to the nuclide conversion is brought into contact with one surface of the structure.

  According to the nuclide conversion method as described above, the occurrence of the nuclide conversion reaction can be promoted by converting the substance subjected to nuclide conversion into a nuclide having a similar isotope ratio configuration.

  According to the nuclide conversion apparatus related to the present invention, for example, nuclide conversion can be performed with a relatively small-scale configuration as compared with a nuclear reactor, an accelerator, etc., and one surface side and the other surface side of the structure By creating a deuterium pressure difference between the two surfaces and generating a deuterium flux from one surface side to the other surface side in the structure, the deuterium and nuclide conversion material On the other hand, the nuclide conversion reaction can be generated with good reproducibility. Further, according to the nuclide conversion apparatus related to the present invention, the pressure difference of the deuterium is easily applied to the structure by pressurizing the occlusion portion by the deuterium supply means and reducing the discharge portion to the vacuum state by the exhaust means. Can be formed. Furthermore, according to the nuclide conversion apparatus related to the present invention, deuterium can be occluded in the structure with an effective large pressure by electrolyzing the electrolytic solution on one surface side of the structure, By depressurizing the discharge portion to a vacuum state by the exhaust means, a pressure difference of deuterium can be easily and reliably formed in the structure.

  Furthermore, according to the nuclide conversion apparatus related to the present invention, a substance for performing nuclide conversion is easily laminated on one surface of the structure by a film forming process such as electrodeposition, vapor deposition, sputtering, etc. be able to. Furthermore, according to the nuclide conversion apparatus related to the present invention, a substance that performs nuclide conversion is easily brought into contact with one surface of the structure by mixing a substance that performs nuclide conversion into a gas or liquid containing deuterium. Can be made. Furthermore, according to the nuclide conversion apparatus related to the present invention, the reproducibility of the occurrence of the nuclide conversion reaction can be improved by providing a mixed layer containing a substance having a low work function in the multilayer structure. . In addition, in the nuclide conversion apparatus related to the present invention, the nuclide conversion reaction can be promoted by converting the substance subjected to nuclide conversion into a nuclide having a similar isotope ratio configuration, and the occurrence of the nuclide conversion reaction Reproducibility can be improved.

  Further, according to the nuclide conversion method related to the present invention, a substance that performs deuterium and nuclide conversion by generating a deuterium flux from one surface side to the other surface side inside the structure. In contrast, the nuclide conversion reaction can be generated with high reproducibility. Further, according to the nuclide conversion method related to the present invention, for example, a material for performing nuclide conversion is laminated on one surface of the structure by film formation processing such as electrodeposition, vapor deposition, sputtering, or deuterium is used, for example. By mixing a substance that performs nuclide conversion into the gas or liquid that is contained, the substance that performs nuclide conversion can be easily brought into contact with one surface of the structure. Furthermore, according to the nuclide conversion method related to the present invention, the nuclide conversion reaction can be promoted by converting the substance subjected to the nuclide conversion into a nuclide having a similar isotope ratio configuration, and the nuclide conversion reaction can be promoted. It is possible to improve the reproducibility with respect to the occurrence of.

  Hereinafter, a nuclide conversion apparatus and a nuclide conversion method according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram for explaining the principle of the nuclide conversion method according to the first embodiment of the present invention, and FIG. 2 is a structure 11 used in the nuclide conversion method according to the first embodiment of the present invention. FIG. 3 is a configuration diagram of the nuclide conversion device 30 according to the first embodiment of the present invention, and FIG. 4 is a multilayer structure 32 in the nuclide conversion device 30 shown in FIG. 5A is a cross-sectional configuration diagram of the mixed layer 22, FIG. 5B is a cross-sectional configuration diagram of the structure 11 including the mixed layer 22, and FIG. It is a block diagram of the apparatus which adds the substance which performs nuclide conversion to the body.

  An apparatus 10 for realizing the nuclide conversion method according to the present embodiment includes, as shown in FIG. 1, for example, palladium (Pd) or an alloy of Pd, other metal that stores hydrogen (for example, Ti), or an alloy thereof. For example, a substantially plate-like structure 11 and a substance 14 for performing nuclide conversion attached on one surface 11A of both surfaces of the structure 11, and one surface 11A of the structure 11 For example, the deuterium pressure in the structure 11 is set to a region 12 where the pressure of deuterium is high due to, for example, pressurization or electrolysis, and the other surface 11B is set as a region 13 where the pressure of deuterium is low due to vacuum evacuation or the like. Is produced by the reaction of deuterium with the substance 14 to be subjected to nuclide conversion. Here, for example, as shown in FIG. 2, the structure 11 is preferably a material having a relatively low work function, that is, a material that easily emits electrons (for example, a work function of less than 3 eV) on the surface of the Pd substrate 23. A mixed layer 22 of (substance) and Pd is formed, and a Pd layer 21 is laminated on the surface of the mixed layer 22.

  As shown in FIG. 3, the nuclide conversion device 30 according to the present embodiment is capable of holding an occlusion chamber 31 in which the inside can be kept airtight, and can be kept airtight inside the occlusion chamber 31 via a multilayer structure 32. A provided discharge chamber 34, a deuterium cylinder 35 for supplying deuterium into the storage chamber 31 via a variable leak valve 33, a discharge chamber vacuum gauge 36 for detecting the degree of vacuum in the discharge chamber 34, for example, a multilayer A mass analyzer 37 for detecting the gaseous reaction product generated from the structure 32 and measuring the amount of deuterium in the discharge chamber 34 to evaluate the amount of deuterium permeated through the multilayer structure 32; The turbo molecular pump 38 that always keeps the inside of the discharge chamber 34 in a vacuum state, and the rotary pump 39 for roughing the inside of the discharge chamber 34 and the turbo molecular pump 38 are provided.

  Furthermore, the nuclide conversion device 30 includes, for example, an electrostatic analyzer 40 that detects photoelectrons and ions emitted from atoms on the surface of the multilayer structure 32 excited by irradiation with X-rays, electron beams, particle beams, and the like. An X-ray gun 41 for XPS (X-ray Photo-electron Spectrometry) that irradiates X-rays on the surface of the multilayer structure 32 exposed to deuterium in the storage chamber 31. A pressure gauge 42 for detecting the pressure in the storage chamber 31 into which deuterium has been introduced, an X-ray detector comprising a high-purity germanium detector 44 having a beryllium window 43, and a vacuum in the storage chamber 31, for example. A storage chamber vacuum gauge 45 for detecting the degree of pressure, a vacuum valve 46 for holding the storage chamber 31 in a vacuum state before introduction of deuterium, a turbo molecular pump 47 for putting the storage chamber 31 in a vacuum state, and a storage chamber 31 and T It is constituted by a rotary pump 48 for roughing the inside of turbomolecular pump 47.

  Then, the multilayer structure 32 is set so that the deuterium pressure is relatively high on the storage chamber 31 side of the multilayer structure 32 and the release chamber 34 side of the multilayer structure 32 is relatively low. By forming a pressure difference of deuterium on both sides, a flow of deuterium is created from the storage chamber 31 side to the discharge chamber 34 side. For example, as shown in FIG. 4, the multilayer structure 32 includes a mixed layer 22 of a substance having a relatively low work function (for example, a substance having a work function of less than 3 eV) and Pd on the surface of the Pd substrate 23. The Pd layer 21 is laminated on the surface of the mixed layer 22, and a cesium (Cs) layer 52 is added as a substance that performs nuclide conversion on the surface of the Pd layer 21.

  The nuclide conversion apparatus 30 according to the present embodiment has the above-described configuration. Next, a method for performing nuclide conversion using the nuclide conversion apparatus 30 will be described with reference to the accompanying drawings.

First, for example, a Pd substrate 23 shown in FIG. 2 (for example, 25 mm long × 25 mm wide × 0.1 mm thick, purity 99.5% or more) is degreased by ultrasonic cleaning in acetone for a predetermined time. Then, in vacuum (for example, 1.33 × 10 ⁻⁵ Pa or less), annealing, that is, heat treatment is performed at a temperature of 900 ° C. for a predetermined time (for example, 10 hours) (step S01). Next, for example, the Pd substrate 23 annealed at room temperature is etched with heavy aqua regia for a predetermined time (for example, 100 seconds) to remove impurities on the surface (step S02).

Next, using a sputtering method using an argon ion beam, a film forming process is performed on the Pd substrate 23 after the etching process, thereby forming the structure 11. Here, for example, the thickness of the Pd layer 21 shown in FIG. 2 is set to 400 · 10 ⁻¹⁰ m, and the mixed layer 22 of the substance having a low work function and Pd has a thickness of, for example, as shown in FIG. and CaO layer 57 is 100 · 10 ^-10 m, for example having a thickness of 100 · 10 ^-10 m and a Pd layer 56 was formed by alternately stacking, a thickness of the mixed layer 22 1000 · 10 ^-10 m It was. Then, the Pd layer 21 was formed at 400 · 10 ⁻¹⁰ m on the surface of the mixed layer 22 to form the structure 11 (step S03).

Next, for example, Cs is added to the film-forming surface of the structure 11 as a substance to be subjected to nuclide conversion by electrolysis of a CsNO ₃ D ₂ O dilute solution (CsNO ₃ / D ₂ O solution). For example, as in the electrodeposition apparatus 60 shown in FIG. 6, a 1 mM CsNO ₃ / D ₂ O solution is used as the electrolytic solution 62, the platinum anode 63 is connected to the anode of the power supply 61, and the structure 11 is connected to the cathode. For example, electrolysis is performed for 10 seconds at a voltage of 1 V, for example, a reaction represented by the following chemical formula (1) is generated on the surface of the structure 11, and the Cs layer 52 is added to form the multilayer structure 32. (Step S04).

Then, the Cs layer 52 of the multilayer structure 32 is directed toward the storage chamber 31 side, and the storage chamber 31 and the discharge chamber 34 are respectively closed in an airtight state with the multilayer structure 32 interposed therebetween. Vacuum evacuation is performed by the rotary pump 39 and the turbo molecular pump 38. Then, the variable leak valve 33 is closed, the vacuum valve 46 is opened, and the storage chamber 31 is evacuated by the rotary pump 48 and the turbo molecular pump 47 (step S05). Next, after the degree of vacuum of the storage chamber 31 is sufficiently stabilized (for example, in a state of 1 × 10 ⁻⁵ Pa or less), the elements present on the surface of the multilayer structure 32 on the storage chamber 31 side are analyzed by XPS. (Step S06). That is, the surface of the multilayer structure 32 is irradiated with X-rays from the X-ray gun 41, and the energy of photoelectrons emitted from the atoms on the surface of the multilayer structure 32 excited by the X-ray irradiation is electrostatically discharged. Detected by the analyzer 40. Thereby, the element which exists on the surface by the side of the storage chamber 31 of the multilayer structure 32 is identified.

Next, after heating the multilayer structure 32 at a temperature of, for example, 70 ° C. with a heating device (not shown), the vacuum valve 46 is closed to evacuate the storage chamber 31, and the variable leak valve 33 is opened. A deuterium gas is introduced into the storage chamber 31 at a predetermined gas pressure, and a nuclide conversion experiment is started. Here, the predetermined gas pressure when introducing the deuterium gas is, for example, 1.01325 × 10 ⁵ Pa (so-called 1 atm). Then, a gaseous reaction product (for example, mass number A = 1 to 140) is measured by the mass analyzer 37 in the discharge chamber 34, and the weight released through the multilayer structure 32 into the discharge chamber 34 is measured. Evaluate the diffusion behavior of hydrogen. Further, X-ray measurement is performed by the high purity germanium detector 44 on the storage chamber 31 side of the multilayer structure 32 (step S07). The amount of deuterium that has permeated through the multilayer structure 32 and released into the discharge chamber 34 is, for example, the degree of vacuum in the discharge chamber 34 detected by the discharge chamber vacuum gauge 36, the exhaust speed of the turbo molecular pump 38, and the like. Calculate based on

A predetermined time, for example, several tens of hours after the introduction of the deuterium gas into the storage chamber 31 is started, the temperature of the multilayer structure 32 is returned to room temperature. Then, the variable leak valve 33 is closed to stop the introduction of deuterium gas into the storage chamber 31, and the vacuum valve 46 is opened to evacuate the storage chamber 31 to complete the nuclide conversion experiment. After the degree of vacuum in the storage chamber 31 is sufficiently stabilized (for example, in a state of 1 × 10 ⁻⁵ Pa or less), the elements present on the surface of the multilayer structure 32 on the storage chamber 31 side are analyzed by XPS. The product is measured (step S08).

  And the process of step S06-step S07 mentioned above is repeated, and the time change of nuclide conversion reaction is measured (step S09). Then, the multilayer structure 32 is taken out from the nuclide conversion device 30, and the nuclide conversion experiment is terminated (step S10).

  Hereinafter, two experimental results in the nuclide conversion experiment performed by the above-described nuclide conversion method according to the present embodiment, that is, Example 1 and Example 2 when the same experiment was performed twice are shown in FIGS. The description will be given with reference. FIG. 7 is a graph showing the spectrum of Pr by XPS on the surface of the multilayer structure 32 shown in FIG. 4, and FIG. 8 shows the number of Cs and Pr atoms on the surface of the multilayer structure 32 shown in FIG. It is a graph showing a time change. According to the XPS analysis results in Example 1 and Example 2, in Example 1 and Example 2, Cs (atomic number Z = 55) of the multilayer structure 32 decreases with time. Pr (praseodymium, atomic number Z = 59) increased like the spectrum of Pr by XPS shown in FIG. Hereinafter, a method of calculating the number of atoms of each element from the spectrum for Cs and Pr by XPS will be described.

The intensity of X-rays irradiated from the X-ray gun 41 to the multilayer structure 32 at the time of measurement by XPS is always constant, and the regions irradiated with these X-rays are the same as those in the first and second embodiments. It was assumed to be the same in each measurement. Further, the region irradiated with X-rays on the surface of the multilayer structure 32 is, for example, a circular region having a diameter of 5 mm, and the depth that can be analyzed by XPS is, for example, estimated from the escape depth of the emitted photoelectrons. 20 · 10 ^-10 m. Since Pd constituting the Pd substrate 23 is an fcc (face-centered cubic lattice) crystal, the number of Pd atoms was calculated to be 3.0 × 10 ¹⁵ from the peak intensity of the Pd spectrum obtained by XPS.

Then, referring to the ionization cross section of each element, that is, the ratio of the core electrons of the element that absorb and excite X-rays, for example, the peak intensity of the spectrum of each element and the peak intensity of the Pd spectrum obtained by XPS And the number of atoms of each element is calculated. In Table 1, the calculated values of the ionization cross sections of each element are shown as relative values when the value (2.22 × 10 ⁻²⁴ m ² ) for C 1s orbital is “1”. In Table 1 below, 2p for Si, 2p for S, and 2p for Cl were calculated as the sum of 2p _3/2 and 2p _1/2 .

As shown in FIG. 8, in Example 1, 1.3 × 10 ¹⁴ Cs present in the initial state decreased to 8 × 10 ¹³ after 48 hours, and 5 × 10 ¹³ after 120 hours. It has decreased to pieces. On the other hand, it was observed that 3 × 10 ¹³ Prs that did not exist before the start of the experiment were detected after 48 hours and increased to 7 × 10 ¹³ after 120 hours. Similarly, in Example 2, the decrease in the number of Cs atoms, the generation of Pr, and the increase in the number of Pr atoms were observed with the passage of time from the start of the experiment, and the same tendency as in Example 1 was observed. Show. Thereby, it can be interpreted that nuclide conversion from Cs to Pr occurs.

In the following, it will be considered whether or not the detected Pr is derived from impurities. In Example 1 and Example 2 which concern on this embodiment mentioned above, since the elemental analysis is performed without taking out the multilayered structure 32 from the vacuum container which consists of the storage chamber 31 and the discharge chamber 34, it is as a cause that an impurity mixes. What can be considered are impurities contained in deuterium gas (D ₂ gas) and impurities inside the multilayer structure 32. The D ₂ gas has, for example, a purity of 99.6%. As impurities, N ₂ and D ₂ 0 are 10 ppm or less, and O _2, CO _2, and CO are 5 ppm or less. _{Even when two} gases were analyzed, gases other than these impurities and hydrocarbons were not detected.

On the other hand, in the multilayer structure 32, the purity of Pd is 99.5%, and the purity of CaO and CsNO ₃ is 99.9%. Further, as a result of quantitative analysis of lanthanoids ( ₅₇ La to ₇₁ Lu) on the multilayer structure 32 before the start of the experiment by glow discharge mass spectrometry (GD-MS), 0.02 ppm of Nd was detected. The other lanthanoids were below the detection limit, that is, 0.01 ppm or less. Here, it is assumed that the detection limit of 0.01 ppm of Pr exists in the multilayer structure 32 (for example, 0.7 g≈7 × 10 ⁻³ mol) used in Examples 1 and 2. As a result, 4.2 × 10 ¹³ Pr atoms exist in the multilayer structure 32.

In this case, assuming that the Pr atoms detected in Example 1 and Example 2 are caused by Pr atoms below the detection limit based on the above assumption, all the Pr atoms below the detection limit are included in the multilayer structure 32. It is necessary to assume that the Pr atoms dispersed and arranged as impurities in the multilayer structure 32 are arranged so as to be concentrated in a region having a depth of several tens · 10 ⁻¹⁰ m from the surface of A physical phenomenon that concentrates only near the surface of the multilayer structure 32 is thermodynamically impossible, and the Pr atoms detected in the first and second embodiments are included in the multilayer structure 32 in advance. We cannot conclude that the impurities were. Moreover, it can be determined that if the impurities are included in the multilayer structure 32 in advance, the change in the number of atoms over time is not observed and a constant value is maintained. From the above, it can be concluded that Pr detected in Example 1 and Example 2 was produced as a result of the nuclide conversion reaction.

In addition, the experimental result in Example 1 and Example 2 mentioned above is, for example, Fusion Technology magazine (Y. Iwamura, T. Itoh, N. Gotoh and I.
Toyoda, "Detection of Anomalous Elements, X-ray and Excess Heat in aD2-Pd
System and its Interpretation by the Electron-Induced Nuclear Reaction
Model ", Fusion Technology, vol.33, No.4, P.476, 1998), which can be explained very well by the EINR model. According to this EINR model, Pr is calculated from Cs as shown in the following formula (1) and In the following chemical formulas (2) and (3), d represents deuterium, e represents an electron, ² n represents a dyneutron, and ν represents a neutrino.

As shown in the chemical formula (2), in the EINR model, deuterium captures electrons to generate dyneutrons, and at the same time, reacts with a substance such as Cs to cause nuclide conversion. Incidentally, beta decay by the chemical formula (3), i.e. ^{141 Cs (= 133 Cs + 4} 2 n) from towards ¹⁴¹ Pr beta ^- decay of symbols is omitted.

As described above, according to the nuclide conversion apparatus 10 according to the present embodiment, the nuclide conversion process is performed with a relatively small configuration without requiring a relatively large apparatus such as a nuclear reactor or an accelerator. Can be applied. In addition, according to the nuclide conversion method according to the present embodiment, the number of Pr atoms detected after the start of the nuclide conversion experiment but not increasing before the start of the experiment is the same as the supplied D ₂ gas or multilayer structure. It is possible to eliminate the possibility of detection due to impurities contained in advance in 32 and reliably show that the nuclide conversion reaction from Cs to Pr has occurred.

  In the above-described embodiment, the multilayer structure 32 is configured by adding the cesium (Cs) layer 52 as a substance that performs nuclide conversion on the surface of the Pd layer 21. However, the present invention is not limited thereto, and the nuclide is not limited thereto. Instead of Cs, another substance such as carbon (C) may be added as a substance to be converted. Hereinafter, as a first modification of the present embodiment, a case where, for example, carbon (C) is added as a substance that performs nuclide conversion on the surface of the Pd layer 21 will be described with reference to FIGS. 9 and 10. FIG. 9 is a graph showing the change over time in the number of atoms of C, Mg, Si and S on the surface of the multilayer structure 32 in Example 3, and FIG. 10 is a graph showing the multilayer structure in Example 4. It is a graph showing the time change of each number of atoms of C, Mg, Si, and S on the surface of 32.

  In this first modification, the point that differs greatly from the first embodiment described above is the method of forming the multilayer structure 32, particularly the processing in step S04 described above. That is, after step S03 described above, the structure 11 composed of the Pd substrate 23, the mixed layer 22 and the Pd layer 21 is exposed to the atmosphere, so that carbon (C) in the atmosphere adheres to the surface of the Pd layer 21. The multilayer structure 32 is formed (step S14). Then, the Pd layer 21 with C attached is directed toward the storage chamber 31 side, the storage chamber 31 and the discharge chamber 34 are closed with the multilayer structure 32 interposed therebetween, and both the storage chamber 31 and the discharge chamber 34 are respectively closed. Vacuum evacuation (step S15). Then, the processing from step S06 described above is performed.

  Hereinafter, two experimental results in the nuclide conversion experiment performed by the nuclide conversion method according to the first modification of the present embodiment, that is, Example 3 and Example 4 when the same experiment was performed twice are attached drawings. Will be described with reference to FIG. In this case, according to the XPS analysis results in Example 3 and Example 4, in Example 3 and Example 4, C of the multilayer structure 32 decreases with time, and Si, which is a reaction product. And S and Mg which is an intermediate product were detected. In the same manner as in the present embodiment described above, the number of atoms of each element was calculated from the spectra for C, Mg, Si, and S by XPS.

  As shown in FIG. 9, in Example 3, the number of C atoms derived from hydrocarbons decreased after 44 hours from the start of the experiment, whereas 44 Mg did not exist before the start of the experiment. It is detected after a time and decreases slightly after 116 hours. Furthermore, Si and S that did not exist before the start of the experiment increased monotonically after 44 hours and after 116 hours.

  As shown in FIG. 10, in Example 4, the number of C atoms derived from hydrocarbons monotonically decreased after 24 hours, 76 hours, and 116 hours after the start of the experiment, whereas the start of the experiment. Mg which did not exist before is formed after 24 hours and decreases monotonically after 76 hours and 116 hours. Furthermore, Si and S that did not exist before the start of the experiment monotonically increased after 24 hours, 76 hours, and 116 hours.

From the above results, it can be concluded that C is nuclide-converted and Mg, Si, and S are generated by the nuclide conversion method according to the first modification of the present embodiment. In this case, according to the EINR model described above, the nuclide conversion of C is represented by the above chemical formula (2) and the following chemical formula (4). In the chemical formula (4), the reaction by the dyneutron cluster (6 ² n, 2 ² n) is shown.

  Hereinafter, as a second modification of the present embodiment, a case where strontium (Sr), for example, is added as a substance that performs nuclide conversion on the surface of the Pd layer 21 will be described with reference to FIGS. FIG. 11 is a cross-sectional configuration diagram showing a multilayer structure 32 according to a second modification of the present embodiment, and FIG. 12 is a graph showing a spectrum of Mo by XPS on the surface of the multilayer structure 32 shown in FIG. FIGS. 13 and 14 are graphs showing temporal changes in the number of atoms of Sr and Mo on the surface of the multilayer structure 32 shown in FIG. FIG. 15 is a graph showing the abundance ratio of naturally occurring Mo along with the change in mass number, and FIG. 16 shows the presence of Mo isotopes observed on the surface of the multilayer structure 32 in the fifth embodiment. FIG. 17 is a graph showing the ratio of the isotopes of naturally occurring Sr added as a substance to be subjected to nuclide conversion together with the change in mass number.

In the second modified example, in the multilayer structure 32 of the first embodiment described above, the Sr layer 53 is added instead of the Cs layer 52 made of a substance that performs nuclide conversion. That is, the point that differs greatly from the first embodiment described above is the method of forming the multilayer structure 32, particularly the processing in step S04 described above. In the second modified example, as the Pd substrate 23, for example, length 25 mm × width 25 mm × thickness 0.1 mm and purity 99.9% or more are used. In the second modification, after the step S03 described above, the electrolysis of SrO of D ₂ O diluted solution _{(Sr (OD) 2 / D} 2 O solution), as a substance undergoes the nuclide, for example Sr structures 11 is added to the film forming surface. For example, in the electrodeposition apparatus 60 shown in FIG. 6, a 1 mM Sr (OD) ₂ / D ₂ O solution is used as the electrolytic solution 62, the platinum anode 63 is connected to the anode of the power supply 61, and the structure 11 is connected to the cathode. Then, for example, electrolysis is performed for 10 seconds at a voltage of 1 V, a reaction shown in the following chemical formula (5) is generated on the surface of the structure 11, and the Sr layer 53 is added to form the multilayer structure 32. (Step S04a).

  Then, the Sr layer 53 of the multilayer structure 32 is directed to the storage chamber 31 side, and the processing from step S05 described above is performed.

  Hereinafter, two experimental results in the nuclide conversion experiment performed by the nuclide conversion method according to the second modification of the present embodiment, that is, Example 5 and Example 6 when the same experiment was performed twice are attached drawings. Will be described with reference to FIG. According to the XPS analysis results in Example 5 and Example 6, in Example 5 and Example 6, the Sr (atomic number Z = 38) of the multilayer structure 32 decreases with time. As in the spectrum of Mo by XPS shown in FIG. 12, Mo (molybdenum, atomic number Z = 42) increased.

Here, when calculating the number of atoms of each element from the spectrum for Sr and Mo obtained by XPS, the same method as in the first embodiment described above was used. That is, the intensity of X-rays irradiated from the X-ray gun 41 to the multilayer structure 32 at the time of measurement with XPS is always constant, and the regions irradiated with these X-rays are the same as those in the fifth and sixth embodiments. It was assumed to be the same in each measurement. Further, the region irradiated with X-rays on the surface of the multilayer structure 32 is, for example, a circular region having a diameter of 5 mm, and the depth that can be analyzed by XPS is, for example, estimated from the escape depth of the emitted photoelectrons. 20 · 10 ^-10 m. Since Pd constituting the Pd substrate 23 is an fcc (face-centered cubic lattice) crystal, the number of Pd atoms was calculated to be 3.0 × 10 ¹⁵ from the peak intensity of the Pd spectrum obtained by XPS.

  Then, referring to the ionization cross section of each element, that is, the ratio of the core electrons of the element that absorb and excite X-rays, for example, the peak intensity of the spectrum of each element and the peak intensity of the Pd spectrum obtained by XPS And the number of atoms of each element was calculated.

As shown in FIG. 13, in Example 5, 1.2 × 10 ¹⁴ Sr present in the initial state decreased to 1.0 × 10 ¹⁴ after 80 hours, and 8 × after 240 hours. It decreases to 10 ¹³ , and after 400 hours, it decreases to 4 × 10 ¹³ . On the other hand, about 2.2 × 10 ¹³ Mo were detected after 80 hours after the start of the experiment, increased to about 3.2 × 10 ¹³ after 240 hours, and increased to about 3.2 × 10 ¹³ after 400 hours. An increase to 8 × 10 ¹³ was observed. Similarly, in Example 6 shown in FIG. 14, with the passage of time from the start of the experiment, the number of Sr atoms decreased, the generation of Mo that did not exist before the start of the experiment, and the number of Mo atoms. An increase was observed, indicating a tendency similar to that in Example 5. In both Example 5 and Example 6, the time change of the decrease in the number of Sr atoms and the time change of the generation and increase of the number of Mo atoms are almost the same. It can be interpreted that the nuclide conversion has occurred. Moreover, in both Example 5 and Example 6, it can be concluded that experimental results with qualitatively good reproducibility are obtained.

Furthermore, in Example 5, after completion of the nuclide conversion experiment, that is, after the above-described step S10, the surface of the multilayer structure 32 is analyzed by secondary ion mass spectrometry (SIMS). The isotopic ratio of Mo was calculated. For example, compared to the isotope abundance ratio of Mo naturally occurring shown in FIG. 15, for example, in the isotope abundance ratio of Mo observed in the fifth embodiment shown in FIG. 16, a specific isotope, i.e. only ⁹⁶ Mo It can be seen that shows a high abundance rate. Here, for example, as shown in FIG. 17, in the isotope abundance ratio of naturally-occurring Sr added to the multilayer structure 32 as a substance that performs nuclide conversion, only a specific isotope, that is, ⁸⁸ Sr protrudes and is high. It turns out that the abundance rate is shown. That is, there is a strong correlation between the isotope abundance ratio of the substance (Sr) to be subjected to nuclide conversion and the isotope abundance ratio of the substance (Mo) that is not present before the start of the experiment and is generated after the end of the experiment It can be concluded that Mo detected in Example 5 and Example 6 was generated by nuclide conversion for Sr.

Furthermore, the experimental results in Example 5 and Example 6 can be explained very well by, for example, the above-described EINR model. For example, ⁹⁶ Mo is generated by the above chemical formula (2) and the following chemical formula (6). it is conceivable that. Incidentally, beta decay by the chemical formula (6), i.e. ^{96 Sr (= 88 Sr + 4} 2 n) from toward the ⁹⁶ Mo beta ^- decay of symbols is omitted.

  Hereinafter, a nuclide conversion apparatus and a nuclide conversion method according to a second embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 18 is a diagram for explaining the principle of the nuclide conversion method according to the second embodiment of the present invention, and FIG. 19 is a configuration diagram of the nuclide conversion apparatus 80 according to the second embodiment of the present invention.

  For example, as shown in FIG. 18, an apparatus 70 for realizing the nuclide conversion method according to the present embodiment includes an anode 71 such as platinum, an alloy of palladium (Pd) or Pd, or other metal that stores hydrogen (for example, , Ti, etc.) or a cathode 72 made of this alloy or the like, a heavy aqueous solution 73 that immerses the anode 71 and one surface of the cathode 72, and a heavy solution that is made liquid-tight by the cathode 72 and contains a substance that performs nuclide conversion, for example. An electrolytic cell 74 filled with an aqueous solution 73 and a vacuum vessel 75 hermetically sealed by a cathode 72 are provided. One surface 72A side of the cathode 72 is set as a region where the pressure of deuterium is high by electrolysis or the like, and the other Since the surface 72B side is made into a region where the pressure of deuterium is low, for example, by vacuum evacuation or the like, a flow of deuterium is generated inside the cathode 72, and deuterium reacts with a substance that performs nuclide conversion. A device that nuclide is carried out by the. Here, the cathode 72 has, for example, the same structure as that of the structure 11 shown in FIG. 2, and is preferably a substance having a relatively low work function on the surface of the Pd substrate 23, that is, a substance that easily emits electrons. A mixed layer 22 of Pd (for example, a material having a work function of less than 3 eV) is formed, and a Pd layer 21 is formed on the surface of the mixed layer 22 by being laminated.

  As shown in FIG. 19, the nuclide conversion device 80 according to the present embodiment includes a power source 81, an electrolytic cell 83 provided with a pressure gauge 82, an electrolytic solution 84 stored in the electrolytic cell 83, a vacuum vessel 85, , A cooling tube 86 made of, for example, an insulating resin for cooling the electrolytic solution 84 in the electrolytic cell 83, a catalyst 87, platinum connected to the cathode of the power supply 81 and immersed in the electrolytic solution 84, etc. The anode electrode 88 and the electrolytic cell 83 are held in a liquid-tight state, and the vacuum vessel 85 is held in an air-tight manner, and the multilayer structure 89 connected to the cathode of the power source 81, the electrolytic cell 83 and the vacuum vessel 85 are provided. The thermostatic chamber 90 stores and controls the temperature, and a vacuum exhaust pump 91 that evacuates the vacuum vessel 85 is configured.

Here, each of the electrolysis cell 83 made of, for example, an insulating resin and the vacuum vessel 85 made of, for example, stainless steel is liquid-tightened by the multilayer structure 89 through, for example, a Kalrez O-ring having excellent chemical resistance. It is sealed in an airtight state, and so to speak, it is connected via a multilayer structure 89. The electrolytic solution 84 stored in the electrolytic cell 83 is a heavy aqueous solution containing, for example, cesium (Cs) as a substance that performs nuclide conversion, for example, a Cs ₂ (SO ₄ ) heavy aqueous solution having a concentration of 3.1 mol / l. It is said that. The catalyst 87 is composed of a platinum black electrodeposited on platinum, generates water from most of hydrogen and oxygen generated by electrolysis of the electrolytic solution 84, and returns it to the electrolytic solution 84 again.

  The nuclide conversion apparatus 80 according to the present embodiment has the above-described configuration. Next, a method for performing nuclide conversion using the nuclide conversion apparatus 80 will be described with reference to the accompanying drawings.

First, the structure 11 is created in the same manner as steps S01 to S03 in the nuclide conversion method according to the first embodiment described above. Then, the structure 11 is used as a multilayer structure 89, the Pd layer 21 of the multilayer structure 89 is directed toward the electrolysis cell 83, and the electrolysis cell 83 and the vacuum vessel 85 are sealed in a liquid-tight state and an air-tight state, respectively ( Step S21). Next, for example, a Cs ₂ (SO ₄ ) heavy aqueous solution having a concentration of 3.1 mol / l is injected into the electrolytic cell 83 as the electrolytic solution 84. Further, a space in the electrolytic cell 83 that is not filled with the electrolytic solution 84 is replaced with nitrogen gas and sealed, and the pressure in the electrolytic cell 83 is maintained at, for example, 1.5 kg / cm ² (step S22).

  Then, the inside of the vacuum vessel 85 is evacuated by the vacuum pump 91 and kept in a vacuum state (step S23). Then, for example, a refrigerant is supplied into the cooling pipe 86 made of an insulating resin or the like, and the temperature in the electrolysis cell 83 is maintained at a predetermined constant temperature (step S24). Then, an anode electrode 88 made of, for example, platinum immersed in an electrolytic solution 84 in the electrolytic cell 83 and a multilayer structure 89 serving as a cathode are connected to a power source 81, and electrolysis is performed using power supplied from the power source 81. A reaction is generated (step S25). Here, the current supplied during the electrolysis is gradually increased from 1 A to 2 A, for example, in 3 hours, and then 2 A is maintained.

  Then, 12 hours after the start of electrolysis, the temperature of the thermostatic chamber 90 is set to 70 ° C., and this temperature is maintained thereafter (step S26). After this electrolysis is continued for a predetermined time, for example, 7 days, the electrolysis is stopped and the temperature of the thermostatic chamber 90 is set to room temperature (step S27). Then, the multilayer structure 89 is removed from the nuclide conversion device 80, and the surface of the multilayer structure 89 is analyzed by secondary ion mass spectrometry (SIMS) (step S28).

  Hereinafter, experimental results in the nuclide conversion experiment performed by the nuclide conversion method according to the present embodiment described above, that is, Example 7 will be described with reference to FIGS. 20 is a diagram showing the surface of the multilayer structure 89 on the electrolysis cell 83 side after the experiment using the nuclide conversion device 80 shown in FIG. 19, and FIG. 21 uses the nuclide conversion device 80 shown in FIG. It is a graph which shows the SIMS analysis result of the surface of the multilayered structure 89 after an experiment.

The deuterium permeation portion 96 shown in FIG. 20 and the deuterium non-permeation portion 95 shown in FIG. 20 have the same secondary ion intensity for ¹⁴⁰ Ce as shown in FIG. However, in ¹³⁹ La and ¹⁴¹ Pr, the portion 96 through which the deuterium permeates, that is, the portion where the nuclide conversion reaction occurs, has a higher secondary ion intensity. In addition, for mass number A = 142, it is impossible to determine whether it is ¹⁴² Ce or ¹⁴² Nd, but the portion 96 through which deuterium permeates has a higher secondary ion intensity. Yes. From this, it can be concluded that at least ¹⁴¹ Pr is a substance produced by nuclide conversion of Cs.

  As described above, according to the nuclide conversion apparatus 80 according to the present embodiment, the nuclide conversion process is performed with a relatively small configuration without requiring a relatively large apparatus such as a nuclear reactor or an accelerator. Can be applied. In addition, although the configuration is different from the nuclide conversion apparatus 30 according to the first embodiment described above, it is possible to obtain an experimental result indicating that a nuclide conversion reaction from Cs to Pr occurs. The effectiveness of the essential means can be shown. In addition, according to the nuclide conversion method of the present embodiment, the nuclide conversion from at least Cs to Pr is made by comparing the portion 96 through which the deuterium permeates in the multilayer structure 89 and the portion 95 through which the deuterium does not pass. It can be shown reliably that the reaction is occurring.

  In the present embodiment, a heavy aqueous solution containing a substance that performs nuclide conversion is used as the electrolytic solution 84. However, the present invention is not limited to this. For example, vacuum deposition or sputtering is performed on one surface of the multilayer structure 89. An electrolytic solution 84 made of a heavy aqueous solution stored in the electrolytic cell 83 is formed by laminating a substance to be subjected to nuclide conversion by the film forming process of the method, for example, Cs, and the surface on which the Cs is laminated faces the inside of the electrolytic cell 83. May be immersed in In this case, the heavy aqueous solution does not need to contain a substance that performs nuclide conversion, that is, Cs.

  In the above-described embodiment, a heavy aqueous solution containing Cs is used as the electrolytic solution 84. However, the present invention is not limited to this. For example, sodium (Na) or the like can be used instead of Cs as a substance that performs nuclide conversion. Other substances may be added. Hereinafter, as a modification of the present embodiment, a case where, for example, sodium (Na) is added to a heavy aqueous solution as a substance that performs nuclide conversion will be described.

In this modified example, the point that differs greatly from the second embodiment described above is the processing in step S22 and subsequent steps described above. That is, after the above-described step S21, a LiOD heavy aqueous solution having a concentration of 4.3 mol / l to which, for example, 400 ppm of sodium is added is injected into the electrolytic cell 83 as the electrolytic solution 84. Further, a space in the electrolytic cell 83 that is not filled with the electrolytic solution 84 is replaced with nitrogen gas and sealed, and the pressure in the electrolytic cell 83 is maintained at, for example, 1.5 kg / cm ² (step S32).

  Then, the inside of the vacuum vessel 85 is evacuated by the vacuum pump 91 and kept in a vacuum state (step S33). Then, for example, a refrigerant is supplied into the cooling pipe 86 made of an insulating resin or the like, and the temperature in the electrolysis cell 83 is maintained at a predetermined constant temperature (step S34). Then, an anode electrode 88 made of, for example, platinum immersed in an electrolytic solution 84 in the electrolytic cell 83 and a multilayer structure 89 serving as a cathode are connected to a power source 81, and electrolysis is performed using power supplied from the power source 81. A reaction is generated (step S35). Here, the current supplied at the time of electrolysis is gradually increased from 0.5 A to 2 A, for example, in 6 hours, and then kept at 2 A.

  Then, after the electrolysis is continued for a predetermined time, for example, 7 days, the electrolysis is stopped and the temperature of the thermostatic chamber 90 is set to room temperature (step S36). Then, the multilayer structure 89 is removed from the nuclide conversion device 80, and the surface of the multilayer structure 89 is analyzed by an electron probe microanalyzer (EPMA) (step S37).

  Hereinafter, experimental results in three nuclide conversion experiments performed by the nuclide conversion method according to the modification of the second embodiment of the present invention described above, that is, Example 8 and implementation when the same experiment was performed three times. Example 9 and Example 10 will be described. In Table 2, the analysis of the electrolytic solution 84 by Inductive Coupled Plasma-Auger Electron Spectrometry (ICP-AES) is performed for Example 8, Example 9, and Example 10. The results are shown. In addition, the analysis result of the electrolytic solution 84 before the start of the experiment was used as a comparative example.

As shown in Table 2, Na is 430 ppm and Al is 1 ppm or less below the detection limit in the electrolytic solution 84 before the start of the experiment. On the other hand, after the experiment of nuclide conversion, Na was several tens of ppm, which is about an order of magnitude lower, and Al was several hundred ppm. The change of the electrolytic solution 84 before and after the start of the experiment is merely an electrolysis by applying a current from the power source 81, and no other substance is added from the outside. Further, in terms of the number of atoms (Atom in Table 2), the decreased number of Na atoms is about 2.2 × 10 ²¹ to 2.0 × 10 ^21, which is almost equal to the increase amount of Al. I can confirm.

  This result is represented by the above chemical formula (2) and the following chemical formula (7) in the above-mentioned EINR model.

Here, Na has a natural abundance of ²³ Na of 100%, and Al has a natural abundance of ²⁷ Al of 100%. From the conventional experimental data, it can be determined that nuclide conversion is likely to occur between nuclides with similar isotope composition, and that Na is likely to be converted to Al. Both Na and Al elements are stable. It can be inferred from the fact that there is only one isotope. Further, as a result of analyzing the surface of the multilayer structure 89 by EPMA, Al was also detected from the central portion of the multilayer structure 89, that is, the portion through which deuterium permeated. Since Al is an amphoteric metal, it can be dissolved in the electrolytic solution 84. However, Al is detected also from the center surface of the multilayer structure 89, so that it is concluded that Na is nuclide-converted and Al is generated. can do.

  In the present embodiment, a heavy aqueous solution containing a substance that performs nuclide conversion is used as the electrolytic solution 84. However, the present invention is not limited to this. For example, vacuum deposition or sputtering is performed on one surface of the multilayer structure 89. An electrolytic solution 84 made of a heavy aqueous solution stored in the electrolytic cell 83 with a layer to be subjected to nuclide conversion by the film forming process of the method, for example, Na stacked, and the surface on which the Na is stacked facing the inside of the electrolytic cell 83. May be immersed in In this case, the heavy aqueous solution does not need to contain a substance that performs nuclide conversion, that is, Na.

  Hereinafter, a nuclide conversion apparatus and a nuclide conversion method according to a third embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 22 is a configuration diagram of a nuclide conversion apparatus 100 according to the third embodiment of the present invention.

  The nuclide conversion device 100 according to the present embodiment includes a discharge container 101 that can be kept airtight inside, and an occlusion container 103 that can be kept airtight inside the release container 101 via a multilayer structure 102. The deuterium cylinder 106 for supplying deuterium into the storage container 103 through the regulator valve 104 and the valve 105, the pressure gauge 107 for detecting the pressure in the storage container 103, and the inside of the discharge container 101 through the vacuum valve 108 A connecting pipe 109 that connects the inside of the storage container 103, a turbo molecular pump 110 that keeps the inside of the discharge container 101 in a vacuum state, and roughing the inside of the release container 101, the storage container 103, and the turbo molecular pump 110. A rotary pump 111 and a vacuum gauge 112 for detecting the degree of vacuum in the discharge container 101 are provided.

  The nuclide conversion apparatus 100 according to the present embodiment has the above-described configuration. Next, a method for performing nuclide conversion using the nuclide conversion apparatus 100 will be described with reference to the accompanying drawings.

  First, for example, the Pd substrate 23 shown in FIG. 2 (for example, diameter 70 mm × thickness 0.1 mm, purity 99.9% or more) is degreased by ultrasonic cleaning in acetone for a predetermined time. Then, annealing, that is, heat treatment is performed in an Ar gas atmosphere at a temperature of, for example, 900 ° C. for a predetermined time (for example, 10 hours) (step S41). Next, the annealed Pd substrate 23 is etched for a predetermined time (for example, 100 seconds) with aqua regia diluted 1.5 times at room temperature, for example, to remove surface impurities (step) S42).

Next, in the same manner as in step S03 described above, the structure 11 is formed by performing a film forming process on the Pd substrate 23 after the etching process using a sputtering method using an argon ion beam (step S43). Then, in the same manner as in the above-described step S04, the Cs layer is formed as a material to be subjected to nuclide conversion by electrolysis of a CsNO ₃ D ₂ O dilute solution (CsNO ₃ / D ₂ O solution). Is added to form the multilayer structure 102 (step S44).

  Then, the Cs layer of the multilayer structure 102 is directed toward the storage container 103 side, and the storage container 103 and the discharge container 101 are respectively sealed in an airtight state with the multilayer structure 102 interposed therebetween. First, the valve 105 is closed, the vacuum valve 108 of the connection pipe 109 is opened, and the discharge container 101 and the storage container 103 are evacuated by the rotary pump 111 and the turbo molecular pump 110 (step S45).

Next, after the multilayer structure 102 is heated to a temperature of, for example, 70 ° C. by a heating device (not shown), the vacuum valve 108 is closed to evacuate the storage container 103, and the valve 105 is opened to store the storage container. A deuterium gas is introduced into the gas chamber 103 at a predetermined gas pressure, and a nuclide conversion experiment is started. Here, the predetermined gas pressure when introducing the deuterium gas is adjusted by the regulator valve 104, for example, 1.01325 × 10 ⁵ Pa (so-called 1 atm) (step S46). Note that the amount of deuterium that has permeated through the multilayer structure 102 and exited into the discharge container 101 is based on, for example, the degree of vacuum in the discharge container 101 detected by the vacuum gauge 112 and the exhaust speed of the turbo molecular pump 110. To calculate.

  A predetermined time, for example, several tens of hours after the introduction of deuterium gas into the storage container 103 is started, the temperature of the multilayer structure 102 is returned to room temperature. Then, the valve 105 is closed to stop introduction of deuterium gas into the storage container 103, and the vacuum valve 108 is opened to evacuate the storage container 103 to complete the nuclide conversion experiment (step S47). . Then, the multilayer structure 102 is removed from the nuclide conversion device 100, and the multilayer structure 102 is etched with aqua regia to create a solution in which elements existing on the surface of the multilayer structure 102 are dissolved. By applying inductive coupled plasma-mass spectrometry (ICP-MS) to this solution, quantitative analysis of elements present on the surface of the multilayer structure 102 is performed (step S48). .

  Hereinafter, two experimental results in the nuclide conversion experiment performed by the above-described nuclide conversion method according to the present embodiment, that is, Example 11 and Example 12 when the same experiment was performed twice with reference to Table 3 will be described. explain. Table 3 below shows the results of analysis by ICP-MS for Example 11 and Example 12. In addition, the analysis result of the solution produced | generated by performing the etching process with aqua regia on the multilayer structure 102 before the experiment start was made into the comparative example.

  As shown in Table 3, in the solution obtained from the multilayer structure 102 before the start of the experiment in the comparative example, the weight of Pr is 0.008 μg and the weight of Cs is 3.8 μg. The amount of Pr is a detection limit value of the measuring instrument and is a value as background noise. On the other hand, in Example 12, the weight of Pr was 0.12 μg which was a sufficiently high value with respect to the background. Further, in Example 11, the weight of Pr increased to 1.3 μg, which is about one digit higher than that in Example 12, and the weight of Cs decreased to 2.3 μg. That is, it can be concluded that the increase in Pr detected in Example 11 and Example 12 is a result of the occurrence of a nuclide conversion reaction from Cs to Pr. In addition, the reaction amount could be increased by increasing the reaction cross section.

  As described above, according to the nuclide conversion apparatus 100 according to the present embodiment, the nuclide conversion process is performed with a relatively small configuration without requiring a relatively large apparatus such as a nuclear reactor or an accelerator. Can be applied. In addition, an experimental result indicating that a nuclide conversion reaction from Cs to Pr occurs in the multilayer structure 102 having a different apparatus configuration and different shape from the nuclide conversion apparatus 30 according to the first embodiment described above. And the effectiveness of the essential means of the present invention can be demonstrated.

  In the first embodiment, the second embodiment, and the third embodiment of the present invention described above, palladium (Pd) is used as a metal that absorbs hydrogen. However, the present invention is not limited to this. It may be an alloy, or another metal that occludes hydrogen such as Ti, Ni, V, or Cu, or an alloy thereof.

It is a figure explaining the principle of the nuclide conversion method concerning a 1st embodiment of the present invention. It is a section lineblock diagram showing a structure used with a nuclide conversion method concerning a 1st embodiment of the present invention. 1 is a configuration diagram of a nuclide conversion device according to a first embodiment of the present invention. It is a cross-sectional block diagram which shows the multilayer structure used with the nuclide conversion apparatus shown in FIG. FIG. 5A is a cross-sectional configuration diagram of the mixed layer, and FIG. 5B is a cross-sectional configuration diagram of the structure including the mixed layer. It is a block diagram of the apparatus which adds the substance which performs nuclide conversion to a structure. FIG. 5 is a graph showing a Pr spectrum by XPS on the surface of the multilayer structure shown in FIG. 4. It is a graph showing the time change of the atomic number of Cs and Pr on the surface of the multilayer structure shown in FIG. In Example 3, it is a graph showing the time change of each atom number of C, Mg, Si, and S on the surface of a multilayer structure. In Example 4, it is a graph showing the time change of each atom number of C, Mg, Si, and S on the surface of a multilayer structure. It is a section lineblock diagram showing multilayer structure 32 concerning the 2nd modification of this embodiment. It is a graph which shows the spectrum of Mo by XPS on the surface of the multilayer structure shown in FIG. It is a graph showing the time change of the number of atoms of Sr and Mo on the surface of the multilayer structure shown in FIG. It is a graph showing the time change of the number of atoms of Sr and Mo on the surface of the multilayer structure shown in FIG. It is a graph which shows the isotope abundance ratio of naturally existing Mo with the change of mass number. It is a graph which shows the isotope abundance ratio of Mo observed on the surface of the multilayer structure in 5th Example with the change of mass number. It is a graph which shows the isotope abundance ratio of naturally occurring Sr added as a substance to be subjected to nuclide conversion together with a change in mass number. It is a figure explaining the principle of the nuclide conversion method concerning the 2nd Embodiment of this invention. It is a block diagram of the nuclide conversion apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the surface by the side of the electrolysis cell of the multilayer structure after the experiment using the nuclide conversion apparatus shown in FIG. It is a graph which shows the SIMS analysis result of the surface of the multilayer structure after an experiment using the nuclide conversion apparatus shown in FIG. It is a block diagram of the nuclide conversion apparatus which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

10, 30, 70, 80, 100 nuclide conversion device 11 structure 21 Pd layer (surface layer)
22 Mixed layer 23 Pd substrate (base material)
31 Occupation room (Occupation part)
32,89,102 Multilayer structure (structure)
34 Release chamber (discharge section)
35,106 Deuterium cylinder (high pressure means, deuterium supply means)
38,110 Turbo molecular pump (low pressure means, exhaust means)
39,111 Rotary pump (low pressure means, exhaust means)
72 Cathode (structure)
81 Power supply (high pressure means, electrolysis means)
83 Electrolysis cell (occlusion)
84 Electrolytic solution 85 Vacuum container (discharge part)
91 Vacuum pump (low pressure means, exhaust means)
101 Discharge container (discharge part)
102 Occlusion container (occlusion part)

Claims (6)

Contacted on one surface of a structure having palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than palladium alloy, and a material having a relatively low work function. For a substance that performs nuclide conversion, it is provided in a nuclide conversion apparatus in which deuterium flows from the one surface side of the structure toward the other surface side,
A nuclide conversion substance contact device, wherein a substance that performs nuclide conversion is brought into contact with the one surface of the structure. 2. The nuclide conversion substance contact device according to claim 1, further comprising an occlusion portion that forms a closed space that can be sealed by the structure on the one surface side of the structure. 3. The material for performing the nuclide conversion is brought into contact with the one surface of the structure by supplying a gas containing the material for performing the nuclide conversion together with deuterium gas to the occlusion unit. The nuclide conversion substance contact device as described. 3. The nuclide conversion substance contact device according to claim 2, wherein a substance that performs the nuclide conversion is stacked on the one surface of the structure in the occlusion part. The electrolytic solution containing the substance that performs the nuclide conversion is supplied into the occlusion part, and the substance that performs the nuclide conversion is brought into contact with the one surface of the structure by electrolysis. Nuclide conversion material contact device. 6. The nuclide conversion substance contact device according to claim 5, wherein a heavy aqueous solution is used as the electrolytic solution, the substance for performing nuclide conversion is brought into contact with the one surface of the structure, and deuterium is supplied.

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