Nuclear battery shielding structure and nuclear battery

Abstract

The invention discloses a nuclear battery shielding structure and a nuclear battery, and relates to the technical field of nuclear batteries, the nuclear battery shielding structure comprises a shielding inner layer arranged outside a radioactive source core block shell, a first gap is arranged between the shielding inner layer and the radioactive source core block shell, and a shielding outer layer is arranged outside the shielding inner layer. According to the shielding structure, on the basis of the shielding inner layer, a material containing specific elements can be added according to an escape energy spectrum to serve as the shielding outer layer, and gamma photons in a specific energy range are effectively shielded; in addition, according to decay energy spectrums of different radioactive sources, different kinds of precious metal can be used as shielding inner layers, the shielding layers added with the specific elements and the precious metal shielding inner layers can be alternately arranged at intervals, and radiation energy escape is reduced step by step. By adopting the structure of combining the shielding inner layer and the shielding outer layer, the surface dose level of the radioactive source pellet can be effectively reduced, the shielding inner layer can be used as a high-stability barrier material, and the shielding outer layer can be used as a high-strength protection structure.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear batteries, and in particular to a nuclear battery shielding structure and a nuclear battery. Background Art

[0002] A nuclear battery is a physical battery that converts the decay energy of radioactive isotopes into electrical energy through a static or dynamic conversion system. Depending on the type of particles emitted by the decay of radioactive isotopes, there are α, β, γ and hybrid nuclear batteries. According to the specific energy conversion method of nuclear batteries, nuclear batteries can be divided into rechargeable nuclear batteries, direct collection nuclear batteries, gas ionization nuclear batteries, Voltaic effect nuclear batteries, temperature difference nuclear batteries, thermionic emission nuclear batteries, electromagnetic radiation energy conversion nuclear batteries, heat engine conversion nuclear batteries, etc.

[0003] The usual energy conversion process of nuclear batteries is:

[0004] 1. Radioactive nuclides decay and release decay energy, which usually exists in the form of particle kinetic energy. For pure β decay, energy is distributed among β particles, electron neutrinos, and daughter nuclei. Since the daughter nucleus energy is much greater than the other two particles, the daughter nucleus kinetic energy can be approximately considered to be zero. Since the reaction cross section between neutrinos and matter is extremely small, for nuclear batteries using pure β decay sources, only the β particle energy is considered. The β particle energy is usually a continuous spectrum, with a typical 90 Sr β - Decays into:

[0005]

[0006] For α decay, energy is distributed between daughter nuclei and α particles. Usually, the kinetic energy of the daughter nuclei accounts for 2% of the decay energy, and the kinetic energy of the α particles accounts for 98%. Usually, when decaying to the daughter nuclei, it first decays to the excited state and then retreats to the ground state, releasing gamma rays in the process. Therefore, for α-type nuclear batteries, when considering decay heat, it is necessary to consider the energy of daughter nuclei and α particles. When using the released α particles, the energy of the escaping α particles should be considered. The fine spectrum of α particles is usually a broadened spectrum of several different energies. The typical α decay is:

[0007]

[0008] 2. The energy deposition of decay particles or daughter nuclei in the conversion material. For example, for thermal conversion nuclear batteries, the kinetic energy of daughter nuclei and the kinetic energy of decay particle deposition are expressed as thermal energy, which ultimately manifests as an increase in material temperature. For ionization nuclear batteries, charged decay particles are deposited in gases or semiconductors and cause ionization, thereby generating ion pairs in the conversion material, which ultimately manifests as an uneven distribution of charge.

[0009] For α particles, they mainly deposit energy by inelastic scattering with matter, ionizing and exciting the matter. The ionized and excited matter usually releases photons to reach the ground state. For β particles, the deposition process includes ionization loss and radiation loss. The radiation loss includes Bremsstrahlung (producing a continuous γ spectrum with an average energy of about half the average energy of the β spectrum) and Cherenkov radiation (mainly continuous visible light). + Particles will produce electron pair annihilation; for γ particles, the deposition process is photoelectric effect, Compton scattering, and electron pair effect (produced when the energy is higher than 1.02 MeV).

[0010] 3. Use dynamic or static energy conversion systems to convert the deposited energy into electrical energy, such as using temperature difference to generate voltage; converting thermal energy into kinetic energy and then into electrical energy; converting the generated ion pairs into electric fields to generate voltage, etc.

[0011] In the above-mentioned decay particle energy deposition process, gamma or X-rays will be directly or indirectly generated outside the nuclear battery system. The sources include undeposited gamma particles and X-rays generated by charged particles in the electric field, which are essentially gamma photons. For substances in this part of the gamma photon environment, whether radiation damage effects occur and the severity of radiation damage will be determined by the amount of energy deposited by gamma photons in it. Therefore, it is necessary to control the gamma radiation field outside the nuclear battery system within a certain range to control radiation damage, thereby ensuring the safety of the surrounding environment or workers. Dose is usually used to quantify the gamma radiation field. In order to reduce the dose, it is usually necessary to add a shielding structure in or outside the nuclear battery system. Conventional shielding structures have the problems of heavy weight and large volume. Summary of the invention

[0012] Based on the fact that the current nuclear battery shielding structure has the problems of being heavy and large in size, the purpose of the present invention is to provide a nuclear battery shielding structure and a nuclear battery. Compared with the conventional use of only a single shielding layer, while having the same shielding effect on the nuclear battery, the volume and mass of the shielding body can be effectively reduced, so as to be more conducive to the efficient design of the nuclear battery, and the internal radioactive core blocks can be secondary protected by the setting of the inner shielding layer.

[0013] The present invention is achieved through the following technical solutions:

[0014] In a first aspect, the present application provides a nuclear battery shielding structure, comprising an inner shielding layer arranged outside an outer shell of a radioactive source core block, a first gap being arranged between the inner shielding layer and the outer shell of the radioactive source core block, and an outer shielding layer being arranged outside the inner shielding layer.

[0015] On the basis of the shielding inner layer, the shielding structure can add materials containing specific elements as the shielding outer layer according to the escape energy spectrum, so as to effectively shield gamma photons in a specific energy range; different types of precious metals can also be used as the shielding inner layer according to the decay energy spectra of different radiation sources, wherein the shielding layer with added specific elements and the precious metal shielding inner layer can be arranged alternately and spaced to gradually reduce the radiation energy escape; the precious metal shielding inner layer and the shielding outer layer with added specific elements are combined by electroplating or gold plating technology.

[0016] The nuclear battery shielding structure of the present invention has the characteristics of high efficiency and light weight. Compared with conventional nuclear batteries that only use a single shielding layer, the nuclear battery shielding structure can effectively reduce the volume and mass of the shielding body while having the same shielding effect on the nuclear battery, so as to be more conducive to the efficient design of the nuclear battery. The internal radioactive core blocks are secondary protected by the setting of the inner shielding layer, and the shielding effect is optimal for γ photons within a certain energy range, thereby achieving an efficient shielding effect.

[0017] The present invention adds a shielding inner layer outside the radiation source core block, so that the maximum dose level of the entire surface after the shielding inner layer is added is lower than 2mSv / h, thereby ensuring the radiation safety of surrounding workers during use and reducing the radiation damage effect of peripheral equipment.

[0018] The present invention adopts a structure combining an inner shielding layer and an outer shielding layer, which can effectively reduce the surface dose level of the radiation source core block, and the inner shielding layer can be used as a high-stability barrier material, and the outer shielding layer can be used as a high-strength protective structure.

[0019] Furthermore, a radiation source core block is arranged inside the radiation source core block shell, and a second gap is arranged between the radiation source core block and the radiation source core block shell.

[0020] Furthermore, the shell of the radiation source core block is made of double-layer Hastelloy.

[0021] The material of the shell of the radioactive source core block in the present invention is made of double-layer Hastelloy, which can ensure the safety of the core block.

[0022] Furthermore, the thickness of the outer shell of the radiation source core block is 1 mm to 3 mm.

[0023] Furthermore, a first gap between the shielding inner layer and the radiation source core block outer shell is 0.5 mm to 2 mm.

[0024] The present invention provides a first gap between the shielding inner layer and the outer shell of the radiation source core block, thereby leaving a margin for thermal expansion caused by the temperature rise after radiation heat generation.

[0025] Furthermore, the material used to make the inner shielding layer includes platinum.

[0026] Furthermore, the thickness of the shielding inner layer is 0.5 mm to 2 mm.

[0027] Furthermore, the material used to make the outer shielding layer includes uranium.

[0028] Furthermore, the axial thickness of the shielding outer layer is 6 cm to 8 cm, and the radial thickness is 5 cm to 8 cm.

[0029] In a second aspect, the present application provides a nuclear battery, including the above-mentioned nuclear battery shielding structure.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] (1) The nuclear battery shielding structure of the present invention has the characteristics of high efficiency and light weight. Compared with conventional nuclear batteries that only use a single shielding layer, the nuclear battery shielding structure can effectively reduce the volume and mass of the shielding body while having the same shielding effect on the nuclear battery, so as to be more conducive to the efficient design of the nuclear battery. The internal radioactive core block is provided with secondary protection by setting the shielding inner layer, and has the best shielding effect for gamma photons within a certain energy range, thereby achieving a high efficiency shielding effect;

[0032] (2) The present invention adds a shielding inner layer outside the radiation source core block, so that the maximum dose level of the entire surface after adding the shielding inner layer is lower than 2mSv / h, thereby ensuring the radiation safety of surrounding workers during use and reducing the radiation damage effect of peripheral equipment;

[0033] (3) The present invention adopts a structure combining an inner shielding layer and an outer shielding layer, which can effectively reduce the surface dose level of the radiation source core block, and the inner shielding layer can be used as a high-stability barrier material, and the outer shielding layer can be used as a high-strength protective structure;

[0034] (4) The shell of the radiation source pellet in the present invention is made of double-layer Hastelloy, which can ensure the safety of the pellet;

[0035] (5) The present invention provides a first gap between the shielding inner layer and the outer shell of the radiation source core block, thereby leaving a margin for thermal expansion caused by the temperature increase after radiation heat generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0037] Figure 1 It is a cross-sectional view of a nuclear battery shielding structure in the present invention;

[0038] Figure 2 This is the escape energy spectrum of the 90Sr-β source nuclear battery core block in Example 1 of the present invention and the energy spectrum after shielding.

[0039] Marks and corresponding parts names in the attached drawings:

[0040] 01-first gap, 02-second gap, 03-radiation source core block, 04-radiation source core block outer shell, 05-shielding inner layer, 06-shielding outer layer. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0042] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to one of ordinary skill in the art that these specific details need not be employed to practice the present invention. In other embodiments, in order to avoid confusing the present invention, well-known materials or methods are not specifically described.

[0043] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0044] In the description of the present invention, the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0045] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment provides a nuclear battery, wherein the radiation source core block 03 is a SrTiO3 cylindrical core block with a size of Φ1.5cm×0.551cm and a density of 3.85g / cm 3 , the system has reached 90 Sr- 90 Y balance, activity is 1000Ci, inside the pellet 90 The Sr abundance is 48%. The radiation source core block 03 uses a double-layer Hastelloy alloy as a shell to ensure the safety of the core block, the thickness of the radiation source core block shell 04 is 2 mm, and the first gap between the radiation source core block 03 and the radiation source core block shell 04 is 1 mm.

[0048] A shielding layer is added outside the radiation source core block housing 04 so that the maximum dose level of the entire surface is lower than 2mSv / h after the shielding layer is added, thereby ensuring the radiation safety of surrounding workers during use and reducing the radiation damage effect of peripheral equipment.

[0049] A 1 mm thick platinum shielding inner layer 05 is used, and a 2 mm second gap 02 is left between the shielding inner layer 05 and the radiation source core block outer shell 04 to allow for thermal expansion caused by the temperature rise after radiation heat generation. 90 The maximum energy of Y beta particles is about 2.3MeV. According to the relationship between the linear attenuation coefficient of the element and the energy, an alloy with uranium as the core element is selected as the shielding outer layer 06. For example, U-8Mo (8% wt-Mo) provides excellent material strength and temperature resistance. The overall simplified structure is shown in the attached figure. Figure 1 shown.

[0050] The axial thickness of the shielding outer layer 06 is set to 6cm, and the radial thickness is set to 5cm. The maximum axial outer dose rate is 1.047mSv / h, and the maximum radial outer dose rate is 1.476mSv / h. When the shielding layer is not added, the dose rates at the two same measurement points are 6.708Sv / h and 4.1368Sv / h, respectively. It can be seen that the setting of the shielding layer can effectively reduce the surface dose level, and the shielding inner layer 05 can be used as a high-stability barrier material, and the shielding outer layer 06 can be used as a high-strength protective structure.

[0051] Figure 2Given the 90 The radiation energy spectrum of the β-type nuclear battery with Sr as the decay source generated by bremsstrahlung is given, and the escape energy spectrum after 1mm platinum or gold shielding is given. After adding the platinum or gold shielding layer, the radiation energy spectrum is significantly reduced compared to the initial value before the addition, indicating that the platinum or gold shielding layer has an excellent shielding effect on bremsstrahlung.

[0052] Example 2

[0053] Based on Example 1, this embodiment provides a nuclear battery. Compared with Example 1, the shielding inner layer 05 of this embodiment is 1 mm thick gold, and other technical features are exactly the same as those of Example 1. The maximum dose rate outside the axial direction is 1.032 mSv / h, and the maximum dose rate outside the radial direction is 1.463 mSv / h. When the shielding layer is not added, the dose rates at the two same measurement points are 6.708 Sv / h and 4.1368 Sv / h, respectively. It can be seen that the setting of the shielding layer can effectively reduce the surface dose level.

[0054] Example 3

[0055] Based on Example 1, this embodiment provides a nuclear battery. Compared with Example 1, the shielding inner layer 05 of this embodiment is 0.5 mm thick platinum, and other technical features are exactly the same as those of Example 1. The maximum dose rate outside the axial direction is 1.061 mSv / h, and the maximum dose rate outside the radial direction is 1.497 mSv / h. When the shielding layer is not added, the dose rates at the two same measurement points are 6.708 Sv / h and 4.1368 Sv / h, respectively. It can be seen that the setting of the shielding layer can effectively reduce the surface dose level.

[0056] Example 4

[0057] Based on Example 1, this embodiment provides a nuclear battery. Compared with Example 1, the shielding inner layer 05 of this embodiment is 2 mm thick platinum, and other technical features are exactly the same as those of Example 1. The maximum dose rate outside the axial direction is 1.011 mSv / h, and the maximum dose rate outside the radial direction is 1.434 mSv / h. When the shielding layer is not added, the dose rates at the two same measurement points are 6.708 Sv / h and 4.1368 Sv / h, respectively. It can be seen that the setting of the shielding layer can effectively reduce the surface dose level.

[0058] Example 5

[0059] Based on Example 1, this embodiment provides a nuclear battery. Compared with Example 1, the axial thickness of the shielding outer layer 06 of this embodiment is 8 cm, the radial thickness is 8 cm, and the other technical features are exactly the same as those of Example 1. The maximum dose rate outside the axial direction is 0.601 mSv / h, and the maximum dose rate outside the radial direction is 0.513 mSv / h. When the shielding layer is not added, the dose rates at the two same measurement points are 6.708 Sv / h and 4.1368 Sv / h, respectively. It can be seen that the setting of the shielding layer can effectively reduce the surface dose level.

[0060] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A nuclear battery shielding structure, characterized in that: The invention comprises a shielding inner layer (05) arranged outside a radiation source core block shell (04), a first gap (01) being arranged between the shielding inner layer (05) and the radiation source core block shell (04), and a shielding outer layer (06) being arranged outside the shielding inner layer (05).

2. A nuclear battery shielding structure according to claim 1, characterized in that: A radioactive source core block (03) is arranged inside the radioactive source core block shell (04), and a second gap (02) is arranged between the radioactive source core block (03) and the radioactive source core block shell (04).

3. A nuclear battery shielding structure according to claim 1, characterized in that: The material of the radiation source core block shell (04) is made of double-layer Hastelloy.

4. A nuclear battery shielding structure according to claim 1, characterized in that: The thickness of the radiation source core block shell (04) is 1 mm to 3 mm.

5. A nuclear battery shielding structure according to claim 1, characterized in that: The first gap (01) between the shielding inner layer (05) and the radiation source core block outer shell (04) is 0.5 mm to 2 mm.

6. A nuclear battery shielding structure according to claim 1, characterized in that: The material of the shielding inner layer (05) includes platinum or gold.

7. A nuclear battery shielding structure according to claim 1, characterized in that: The thickness of the shielding inner layer (05) is 0.5 mm to 2 mm.

8. A nuclear battery shielding structure according to claim 1, characterized in that: The material used to make the shielding outer layer (06) includes uranium.

9. A nuclear battery shielding structure according to claim 1, characterized in that: The shielding outer layer (06) has an axial thickness of 6 cm to 8 cm and a radial thickness of 5 cm to 8 cm.

10. A nuclear battery, characterized in that: A nuclear battery shielding structure comprising any one of claims 1 to 9.

Images