Method and device for recycling activated beryllium, method and apparatus for manufacturing radioactive battery, and radioactive battery

Abstract

To provide a method that enables all steps of recycling activated beryllium to be carried out continuously and rapidly in a dry process without using silane gas, which is difficult to handle and highly hazardous, and to provide a radioactive battery utilizing the recycled activated beryllium.SOLUTION: Activated beryllium (12) is reacted in a dry process with pulsating halogen gas (20, 21) so as to efficiently produce beryllium halide (22), and the generated beryllium halide (22) is reduced to metallic beryllium (32) in the dry process using hydrogen gas (40). In addition, laser light (42) is radiated to recycled activated beryllium (38) obtained by the recycling method, so that isotopes of beryllium with atomic numbers 9 and 10 are separated, thereby obtaining a radioactive battery (60) including the beryllium with atomic number 10.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for recycling activated beryllium, which removes activated impurities from used beryllium that has been activated by neutron irradiation, recovers the beryllium, and reuses it; a method and apparatus for manufacturing a radioactive battery that uses the recovered beryllium; and a radioactive battery. [Background technology]

[0002] Fusion reactors use approximately 200 tons of beryllium metal per reactor as a neutron multiplier. Beryllium is a rare metal, and only about 250 tons are produced annually worldwide, meaning that it cannot be used sustainably in fusion reactors unless it is recycled.

[0003] Therefore, one of the inventors proposed in Patent Document 1 a method for recycling activated beryllium, which comprises a first step of producing high-purity halide beryllium from activated beryllium using halogen gas, and a second step of reducing the halide beryllium to metallic beryllium.

[0004] Furthermore, with regard to power generation using radiation, Non-Patent Document 1 describes Coleman's radioactive battery that uses strontium Sr. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3190005 [Patent Document 2] Patent No. 6914544 [Non-patent literature]

[0006] [Non-Patent Document 1] Material Testing, Vol. 5, No. 39 (December 1956), pp. 92-95 (Figure 2) [Non-patent document 2] J.Behler,and M.Parrinello,Phys.Rev.Lett.98,146401(2007) Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the method for recycling activated beryllium proposed in Patent Document 1, halogenated beryllium was reduced using silane gas, which is pyrophoric at concentrations of 3% or more, has a low lower explosion limit of 1.37 vol%, and a high upper explosion limit of 100 vol%. As a result, not only did the gas spontaneously ignite and burn even in the absence of an ignition source, but it was also highly irritating and could cause emphysema if inhaled, making it difficult to handle.

[0008] To solve these problems, a beryllium recycling system has been developed that uses a wet reduction process using liquid magnesium, as shown in Figure 1.

[0009] In Figure 1, reference numeral 10 denotes an example of a neutron reflector made of beryllium (Be). Its central beryllium portion 12 is cut from the upper and lower adapters 14, 16, and 18, and sublimated at approximately 500°C by a constant flow of halogen gas, yielding beryllium halide 22. During this process, highly activated impurities in the beryllium that emit gamma rays and the like do not sublimate, so residue 24 is produced and removed from the activated beryllium. The resulting beryllium halide grains 32 are then wet-reduced with magnesium liquid, as shown in the following formula (1), and beryllium electrodes 34 are produced by vacuum casting. BeCl2(s)+2Mg(l) → 2MgCl(s)+Be(s) …(1)

[0010] The manufactured beryllium electrode 34 is turned into beryllium microspheres 36 by, for example, the rotating electrode method proposed by the applicant in Patent Document 2.

[0011] However, this method uses a wet reduction process using liquid magnesium (Mg) in the second step to reduce metal beryllium, so it cannot be carried out continuously with the dry first step to produce beryllium halide, and is therefore a batch process, which is very inefficient to operate.Furthermore, there are problems such as the generation of secondary radioactive waste, such as magnesium liquid after reduction, during the reaction.

[0012] Furthermore, the radioactive battery described in Non-Patent Document 1 uses 90Sr as a radiation source, and therefore has a problem of a short half-life of 28 or 29 years and a short lifespan.

[0013] The present invention was made to solve the above-mentioned conventional problems, and its first object is to enable the entire process of recycling activated beryllium to be carried out continuously and quickly in a dry manner without using silane gas, which is difficult to handle and highly dangerous.

[0014] A second objective of the present invention is to provide a semi-permanently usable radioactive battery by utilizing recovered beryllium 10Be. Note that 10Be has a half-life of approximately 1.5 million years, which is approximately 50,000 years longer than 90Sr. [Means for solving the problem]

[0015] The present invention solves the first problem by providing a method for recycling activated beryllium, which comprises a first step of dry-conditionally reacting activated beryllium with pulsating halogen gas to produce halogenated beryllium, and a second step of dry-conditionally reducing the halogenated beryllium produced to metallic beryllium using hydrogen gas.

[0016] The present invention also provides an apparatus for recycling activated beryllium, comprising: means for dry-processing activated beryllium with a halogen gas to produce halogenated beryllium; means for pulsating the halogen gas; and means for reacting the halogenated beryllium produced with hydrogen gas or the like to reduce it to metallic beryllium.

[0017] The present invention also solves the second problem by providing a radioactive battery containing activated beryllium 10Be recovered by the recycling method.

[0018] The present invention also solves the second problem by irradiating the activated beryllium recovered by the recycling method with laser light to separate the beryllium isotopes of atomic numbers 9 and 10, thereby obtaining a radioactive battery containing beryllium with atomic number 10.

[0019] The present invention also provides a radioactive battery produced by the above method.

[0020] The present invention also provides a radioactive battery manufacturing apparatus comprising: the recycling apparatus; and means for irradiating the activated beryllium recovered by the recycling apparatus with laser light to separate the beryllium isotopes of atomic numbers 9 and 10, thereby obtaining a radioactive battery containing beryllium with atomic number 10. [Effects of the Invention]

[0021] According to the present invention, the entire process of recycling activated beryllium can be carried out continuously and quickly in a dry manner without using silane gas, which is difficult to handle and highly dangerous.

[0022] Hydrogen is a flammable gas, but it cannot burn without a substance that aids combustion (a combustion-supporting gas). Its flammability limits are narrower than those of silane gas, with a lower limit of 4.0 vol% and an upper limit of 75.0 vol%. Furthermore, it is not particularly toxic, making it safer and easier to handle than silane gas.

[0023] Furthermore, since the halogen gas is pulsated, the halogenation reaction can be promoted.

[0024] In other words, while halogen gas was conventionally fed at a constant flow rate in the first step of halogenation-based impurity removal, in the present invention, the halogen gas is pulsated, thereby accelerating the halogenation reaction. This was based on the results of a simulation conducted by the present inventors, which shows the dependence of the beryllium desorption number on the inflow rate of chlorine gas Cl molecules, as shown in Figure 2. Specifically, for a temperature of T = 773 K and a flow rate of V = 13,098 m / s, the dependence of the beryllium desorption number on the chlorine gas flow rate was investigated using the neural network molecular dynamics (NNMD) method described in Non-Patent Document 2, for both a constant flow rate and a pulsating flow. As shown in Figure 2, a comparison of the chlorine gas flow rate dependences revealed a higher beryllium desorption number with a pulsating flow, confirming that for the same chlorine gas inflow rate, the beryllium desorption number increases when pulsating flow is taken into account.

[0025] Furthermore, since the entire process is dry, secondary radioactive waste such as Mg liquid after reduction can be reduced to zero.

[0026] Furthermore, the radioactive battery according to the present invention uses 10Be, which has a very long half-life of 1.5 million years, and therefore can be used semi-permanently for 1.5 million years. [Brief explanation of the drawings]

[0027] [Figure 1] Diagram showing the configuration of an example of a beryllium recycling system that uses liquid magnesium for reduction [Figure 2] FIG. 10 is a diagram illustrating an example of the dependence of the number of beryllium desorption on the amount of chlorine gas molecules flowing in, for explaining the principle of the present invention. [Figure 3] FIG. 1 is a diagram showing the configuration of an embodiment of a beryllium recycling system according to the present invention. [Figure 4] Cross-sectional view showing a modified example of beryllium for radioactive batteries [Figure 5] A diagram showing an example of how recovered beryllium can be reused. [Figure 6] A diagram showing another example [Figure 7] A similar diagram showing the effect of another example DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the contents described in the following embodiments and examples. Furthermore, the constituent elements in the embodiments and examples described below include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments and examples described below may be appropriately combined or appropriately selected for use.

[0029] The overall configuration of a beryllium recycling system according to an embodiment of the present invention is shown in Fig. 3. The system is the same as the example shown in Fig. 1 except that a halogen gas pulsating device 21 is provided on the outlet side of halogen gas supply device 20 to supply pulsating halogen gas, and that H gas supplied from H gas supply device 40 is used instead of Mg liquid to perform the dry reduction according to the following formula (2), and therefore a detailed description thereof will be omitted. BeCl2(s)+H2(g) → 2HCl(l)+Be(s)…(2)

[0030] The recovered beryllium is irradiated with neutrons, so an isotope with atomic number 10 exists. This 10Be is Be that only emits beta rays, and because current flows in the opposite direction to the beta rays, it can be used as a raw material for radioactive batteries. 10Be can be produced by using an isotope separation laser irradiation device 42 to irradiate recycled Be (for example, coin-shaped Be (referred to as a Be coin) 38 cut from a beryllium electrode 34) with laser light whose wavelength has been adjusted using, for example, the atomic method, odd-even method, or molecular method of laser isotope separation, thereby isotope separating the atomic numbers 9 and 10.

[0031] An example of a radioactive battery manufactured in this manner is shown in Fig. 3. This radioactive battery 60 includes Be coins 44 in which 10Be has been isotope-separated, a collector 62 made of, for example, aluminum, an insulator 64, tungsten 66, steel 68, an anode 70, a cathode 72, and a container 74.

[0032] It is also possible to use Be coins or Be grains 32 containing a mixture of 9Be and 10Be in the radioactive battery 60 without separating the 10Be.

[0033] Alternatively, a beryllium film 48 can be formed by depositing a paste of 10Be that has been isotope separated by a laser onto a metal plate 46 as shown in Figure 4, and then placing the metal plate 46 so that beta rays are emitted downward (as in Figure 3) in a radioactive battery 60. Although beta rays have low penetrating power, forming a thin film as shown in Figure 4 allows for effective use of beta rays from the inside.

[0034] Another example of the reuse of recovered beryllium is shown in Figure 5. Deuterium and tritium generate fast neutrons through a nuclear fusion reaction in a plasma state. These fast neutrons are then injected into a neutron multiplier 50 made of beryllium, for example, in an experimental fusion reactor, where each fast neutron is multiplied into two thermal neutrons. These thermal neutrons are then injected into a tritium breeder 52 made of lithium, for example, where the fuel tritium is produced and helium is also generated.

[0035] Further examples of the reuse of recovered beryllium are shown in Figures 6 and 7. Figure 6(B) shows a cross section of the central beryllium portion 12 of the neutron reflector 10 shown in Figure 6(A). For example, beryllium microspheres 36 are packed in a helium gas atmosphere between an outer rectangular tube 13 made of aluminum and an inner cylinder 17. The ratio of the amount of helium produced in stainless steel (SUS), He-appm, to the amount of displacement damage (dpa), He-appm / dpa, can be controlled by the neutron reflector 10 packed with beryllium microspheres 36. In the example of Figure 6(B), an irradiation capsule with a diameter of 40 mm can be inserted into the inner cylinder 17.

[0036] Figure 7 shows the simulation results for the fusion conditions in the example of Figure 6. Figure 7 shows the He-production rate (He-appm) versus the displacement damage rate (dpa), with the thin solid line A representing the case of a beryllium reflector element, the dashed line B representing the case of a beryllium microsphere packing rate of 80%, the dotted line C representing the case of a beryllium microsphere packing rate of 60%, and the thick solid line D representing the case of an aluminum reflector element. This makes it possible to efficiently utilize the space inside the irradiation capsule.

[0037] In the above embodiment, chlorine gas is used as the halogen gas, but the type of halogen gas is not limited to this, and for example, fluorine gas or the like can also be used. [Explanation of symbols]

[0038] 10...Neutron reflector 12...Beryllium section 20...Halogen gas supply device 21...Halogen gas pulsation device 22...Beryllium halide 32...Beryllium grains 34...Beryllium electrode 36...Beryllium microspheres 38, 44...Beryllium coins 40...Hydrogen (H2) gas supply device 42...Laser irradiation device for isotope separation 46...Metal plate 48...Beryllium film 50...Neutron multiplier 60...Radioactive battery

Claims

1. a first step of dry-reacting activated beryllium with pulsating halogen gas to produce beryllium halide; a second step of reducing the produced beryllium halide to metallic beryllium using hydrogen gas in a dry process; A method for recycling activated beryllium, comprising:

2. a means for reacting activated beryllium with a halogen gas in a dry state to produce a beryllium halide; means for pulsating the halogen gas; a means for reducing the produced beryllium halide with hydrogen gas to produce metallic beryllium; 1. A recycling device for activated beryllium, comprising:

3. A radioactive battery comprising activated beryllium recovered by the recycling method according to claim 1.

4. A method for producing a radioactive battery, comprising irradiating activated beryllium recovered by the recycling method of claim 1 with laser light to separate beryllium with atomic numbers 9 and 10 into isotopes, thereby obtaining a radioactive battery containing beryllium with atomic number 10.

5. A radioactive battery produced by the method of claim 4.

6. The recycling device according to claim 2; a means for irradiating the activated beryllium recovered by the recycling device with laser light to separate the beryllium with atomic numbers 9 and 10 into isotopes, thereby obtaining a radioactive battery containing beryllium with atomic number 10; A radioactive battery manufacturing apparatus comprising:

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