Nuclear battery shielding structure and nuclear battery

Abstract

The application discloses a nuclear battery shielding structure and a nuclear battery, and relates to the technical field of nuclear batteries, which comprises a shielding inner layer arranged outside a radioactive source pellet shell, a first gap is arranged between the shielding inner layer and the radioactive source pellet shell, and a shielding outer layer is arranged outside the shielding inner layer. The shielding structure can add materials containing specific elements as the shielding outer layer on the basis of the shielding inner layer according to the escape energy spectrum, so that the gamma photons in a specific energy range are effectively shielded; different kinds of noble metals can be used as the shielding inner layer according to the decay energy spectrum of different radioactive sources, and the shielding layer containing specific elements and the noble metal shielding inner layer can be alternately and spacedly arranged to gradually reduce the radiation energy escape. The combination of the shielding inner layer and the shielding outer layer can effectively reduce the surface dose level of the radioactive source pellet, and 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] This invention relates to the field of nuclear battery technology, specifically to a nuclear battery shielding structure and a nuclear battery. Background Technology

[0002] A nuclear battery is a physical battery that converts the decay energy of a radioactive isotope into electrical energy through a static or dynamic conversion system. Based on the type of particles emitted by the radioactive isotope decay, nuclear batteries are classified into alpha, beta, gamma, and hybrid types. According to the specific energy conversion method, nuclear batteries can be classified into rechargeable nuclear batteries, direct collection nuclear batteries, gas ionization nuclear batteries, voltaic effect nuclear batteries, thermoelectric nuclear batteries, thermionic emission nuclear batteries, electromagnetic radiation energy conversion nuclear batteries, and thermomechanical conversion nuclear batteries, etc.

[0003] The typical energy conversion process of a nuclear battery is as follows:

[0004] 1. The decay of radioactive nuclides releases decay energy, which usually exists in the form of the kinetic energy of particles. For pure beta decay, energy is distributed among the beta particle, the electron neutrino, and the daughter nucleus. Since the energy of the daughter nucleus is much greater than that of the other two particles, its kinetic energy can be approximated as zero. Because the reaction cross-section between neutrinos and matter is extremely small, for nuclear batteries using pure beta decay sources, only the beta particle energy is considered. The beta particle energy is usually a continuous spectrum, typically... 90 Sr's β - Decays into:

[0005]

[0006] For alpha decay, energy is distributed between the daughter nucleus and the alpha particles. Typically, the daughter nucleus's kinetic energy accounts for 2% of the decay energy, while the alpha particles' kinetic energy accounts for 98%. When decaying to the daughter nucleus, it usually first decays to an excited state and then returns to the ground state, releasing gamma rays in the process. Therefore, for alpha-type nuclear batteries, when considering decay heat, the energy of both the daughter nucleus and the alpha particles needs to be taken into account. When utilizing the released alpha particles, the energy of the escaping alpha particles needs to be considered. The fine spectrum of alpha particles is usually a broadened spectrum of several different energies. A typical alpha decay is as follows:

[0007]

[0008] 2. Energy deposition of decay particles or daughter nuclei in conversion materials. For example, in thermal conversion nuclear batteries, the kinetic energy of daughter nuclei and the kinetic energy of decay particle deposition are manifested as thermal energy, which ultimately manifests as an increase in material temperature. In ionization nuclear batteries, charged decay particles are deposited in gas or semiconductors, causing ionization, which in turn generates ion pairs in the conversion material, ultimately manifesting as uneven charge distribution.

[0009] For alpha particles, energy is primarily deposited through inelastic scattering with matter, ionizing and exciting the matter. Ionized and excited matter typically releases photons and reaches its ground state. For beta particles, the deposition process includes ionization loss and radiation loss. Radiation loss includes bremsstrahlung (producing a continuous gamma spectrum with an average energy approximately half that of the beta spectrum) and Cherenkov radiation (primarily continuous visible light). + Particles will produce electron-electron annihilation; for γ particles, the deposition process is the photoelectric effect, Compton scattering, and electron-electron pair effect (which occurs above 1.02 MeV).

[0010] 3. Use dynamic or static energy conversion systems to convert deposited energy into electrical energy. For example, use temperature differences to generate voltage; convert thermal energy into kinetic energy and then into electrical energy; convert generated ion pairs into an electric field to generate voltage, etc.

[0011] During the decay particle energy deposition process described above, gamma or X-rays are generated directly or indirectly outside the nuclear battery system. These sources include undeposited gamma particles and X-rays generated by charged particles in an electric field; both are essentially gamma photons. For matter within this gamma photon environment, the magnitude of the energy deposited by the gamma photons determines whether radiation damage occurs and the severity of that damage. Therefore, it is necessary to control the gamma radiation field outside the nuclear battery system within a certain range to control radiation damage and ensure the safety of the surrounding environment and personnel. Dosing is typically used to quantify the gamma radiation field. To reduce the dose, shielding structures are usually added to or outside the nuclear battery system. Conventional shielding structures are heavy and bulky. Summary of the Invention

[0012] Given the current shielding structures for nuclear batteries are heavy and bulky, the purpose of this invention is to provide a nuclear battery shielding structure and a nuclear battery that, compared to the conventional use of only a single shielding layer, can effectively reduce the volume and mass of the shielding body while achieving the same shielding effect for the nuclear battery. This makes it more conducive to the efficient design of the nuclear battery, and the inner shielding layer provides secondary protection for the internal radioactive core.

[0013] This invention is achieved through the following technical solution:

[0014] In a first aspect, this application provides a nuclear battery shielding structure, including an inner shielding layer disposed outside the outer shell of a radioactive source core, a first gap being provided between the inner shielding layer and the outer shell of the radioactive source core, and an outer shielding layer being disposed outside the inner shielding layer.

[0015] Based on the inner shielding layer, this shielding structure can add materials containing specific elements as an outer shielding layer according to the escape energy spectrum to effectively shield gamma photons in a specific energy range. It can also use different types of precious metals as the inner shielding layer according to the decay energy spectrum of different radiation sources. The shielding layer with added specific elements and the inner shielding layer with precious metals can be arranged alternately to reduce radiation energy escape step by step. The inner shielding layer with precious metals and the outer shielding layer with added specific elements are combined by electroplating or gold plating.

[0016] The nuclear battery shielding structure of this invention is characterized by high efficiency and lightweight. Compared with conventional nuclear batteries that only use a single shielding layer, this nuclear battery shielding structure can effectively reduce the volume and mass of the shielding body while achieving the same shielding effect for the nuclear battery. This makes it more conducive to the efficient design of the nuclear battery. Furthermore, the inner shielding layer provides secondary protection for the internal radioactive core, achieving the best shielding effect for γ photons within a certain energy range, thus achieving a highly efficient shielding effect.

[0017] This invention, by adding a shielding inner layer to the outside of the radioactive source core, can ensure that the maximum dose level of the overall surface is below 2 mSv / h after the addition of the shielding inner layer, thereby protecting the radiation safety of surrounding personnel and reducing the radiation damage effect on peripheral equipment during use.

[0018] This invention employs a structure combining an inner shielding layer and an outer shielding layer, which can effectively reduce the surface dose level of the radioactive source core. Furthermore, the inner shielding layer can serve as a highly stable barrier material, while the outer shielding layer can serve as a high-strength protective structure.

[0019] Furthermore, a radioactive source core is disposed inside the outer shell of the radioactive source core, and a second gap is provided between the radioactive source core and the outer shell of the radioactive source core.

[0020] Furthermore, the outer shell of the radioactive source core is made of a double-layered Hastelloy alloy.

[0021] The outer shell of the radioactive source core in this invention is made of a double-layered Hastelloy alloy, which can ensure the safety of the core.

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

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

[0024] By setting a first gap between the inner shielding layer and the outer shell of the radiation source core, the present invention can provide a margin for thermal expansion caused by the temperature rise after radiation heat generation.

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

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

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

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

[0029] Secondly, this application provides a nuclear battery, including the aforementioned 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 in this invention has the characteristics of high efficiency and light weight. Compared with conventional nuclear batteries that only use a single shielding layer, this nuclear battery shielding structure can effectively reduce the volume and weight of the shielding body while having the same shielding effect on the nuclear battery, which is more conducive to the efficient design of the nuclear battery. Furthermore, the inner shielding layer provides secondary protection for the internal radioactive core, and has the best shielding effect on γ photons within a certain energy range, thereby achieving a highly efficient shielding effect.

[0032] (2) By adding a shielding inner layer to the outside of the radioactive source core, the present invention can ensure that the maximum dose level of the overall surface is less than 2mSv / h after the shielding inner layer is added, thereby ensuring the radiation safety of the surrounding staff and reducing the radiation damage effect of the peripheral equipment during use.

[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 radioactive source core block. The inner shielding layer can serve as a highly stable barrier material, and the outer shielding layer can serve as a high-strength protective structure.

[0034] (4) The outer shell of the radioactive source core block in this invention is made of double-layer Hastelloy, which can ensure the safety of the core block;

[0035] (5) By setting a first gap between the inner shielding layer and the outer shell of the radiation source core, the present invention can provide a margin for thermal expansion caused by the temperature rise after radiation heat generation. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

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

[0038] Figure 2 The images show the escape energy spectrum and the shielded energy spectrum of the 90Sr-β source nuclear battery cell in Embodiment 1 of the present invention.

[0039] The attached diagram shows the markings and corresponding component names:

[0040] 01-First gap, 02-Second gap, 03-Radioactive source core, 04-Radioactive source core outer shell, 05-Inner shielding layer, 06-Outer shielding layer. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0042] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known materials or methods have not been specifically described in order to avoid obscuring the invention.

[0043] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and 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 this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0045] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment provides a nuclear battery in which the radioactive source chip 03 is a cylindrical SrTiO3 chip with dimensions of Φ1.5cm × 0.551cm and a density of 3.85g / cm³. 3 The system has reached 90 Sr- 90 Y-equilibrium, activity 1000 Ci, within the core. 90 The Sr abundance is 48%. The radioactive source chip 03 uses a double-layer Hastelloy as the outer shell to ensure the safety of the chip. The thickness of the outer shell 04 is 2 mm, and the first gap between the radioactive source chip 03 and the outer shell 04 is 1 mm.

[0048] A shielding layer is added to the outer shell 04 of the radioactive source core to ensure that the maximum dose level on the overall surface is below 2 mSv / h after the shielding layer is added, thereby ensuring the radiation safety of surrounding personnel during use and reducing the radiation damage effect of peripheral equipment.

[0049] A 1mm thick platinum layer 05 is used as the inner shielding layer, and a 2mm second gap 02 is left between the inner shielding layer 05 and the outer shell 04 of the radiation source core to allow for thermal expansion caused by the temperature rise after radiation heat generation. This is because the system is in equilibrium at this point. 90 The maximum energy of the β particles of Y is approximately 2.3 MeV. Based on the relationship between the linear decay coefficient of elements and energy, an alloy with uranium as the core element was selected as the outer shielding layer O6. Taking U-8Mo (8% wt-Mo) as an example, it provides excellent material strength and temperature resistance. The overall simplified structure is shown in the attached figure. Figure 1 As shown.

[0050] With the outer shielding layer 06 having an axial thickness of 6 cm and a radial thickness of 5 cm, the maximum axial dose rate was 1.047 mSv / h and the maximum radial dose rate was 1.476 mSv / h. Without the shielding layer, the dose rates at the two same measurement points were 6.708 Sv / h and 4.1368 Sv / h, respectively. This demonstrates that the shielding layer effectively reduces the surface dose level, and the inner shielding layer 05 serves as a highly stable barrier material, while the outer shielding layer 06 provides a high-strength protective structure.

[0051] Figure 2The following is given 90 The radiation spectrum of a β-type nuclear battery with Sr as the decay source, generated by bremsstrahlung, is presented, along with the escape spectrum after 1 mm of platinum or gold shielding. The radiation spectrum significantly decreased after adding the platinum or gold shielding layer compared to the initial value, indicating that the platinum or gold shielding layer has excellent shielding effect against bremsstrahlung.

[0052] Example 2

[0053] Based on Example 1, this embodiment provides a nuclear battery. Compared to Example 1, the inner shielding layer 05 in this embodiment is made of 1 mm thick gold, while other technical features are identical to those in Example 1. The maximum axial outward dose rate is 1.032 mSv / h, and the maximum radial outward dose rate is 1.463 mSv / h. When no shielding layer is added, the dose rates at two identical measurement points are 6.708 Sv / h and 4.1368 Sv / h, respectively. Therefore, the shielding layer effectively reduces the surface dose level.

[0054] Example 3

[0055] Based on Example 1, this example provides a nuclear battery. Compared to Example 1, the inner shielding layer 05 in this example is made of 0.5 mm thick platinum, while other technical features are identical to those in Example 1. The maximum axial outward dose rate is 1.061 mSv / h, and the maximum radial outward dose rate is 1.497 mSv / h. Without the shielding layer, the dose rates at two identical measurement points are 6.708 Sv / h and 4.1368 Sv / h, respectively. This demonstrates that the shielding layer effectively reduces the surface dose level.

[0056] Example 4

[0057] Based on Example 1, this embodiment provides a nuclear battery. Compared to Example 1, the inner shielding layer 05 in this embodiment is 2 mm thick platinum, while other technical features are identical to those in Example 1. The maximum axial outward dose rate is 1.011 mSv / h, and the maximum radial outward dose rate is 1.434 mSv / h. When no shielding layer is added, the dose rates at two identical measurement points are 6.708 Sv / h and 4.1368 Sv / h, respectively. Therefore, the shielding layer effectively reduces the surface dose level.

[0058] Example 5

[0059] Based on Example 1, this embodiment provides a nuclear battery. Compared to Example 1, the axial thickness and radial thickness of the outer shielding layer 06 in this embodiment are 8 cm, while other technical features are exactly the same as in Example 1. The maximum axial dose rate is 0.601 mSv / h, and the maximum radial dose rate is 0.513 mSv / h. When no shielding layer is added, the dose rates at two identical measurement points are 6.708 Sv / h and 4.1368 Sv / h, respectively. Therefore, the shielding layer effectively reduces the surface dose level.

[0060] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment 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 within the scope of protection of the present invention.

Claims

1. A nuclear battery shielding structure, characterized in that, The system includes an inner shielding layer (05) disposed outside the outer shell (04) of the radioactive source core, with a first gap (01) between the inner shielding layer (05) and the outer shell (04) of the radioactive source core, and an outer shielding layer (06) disposed outside the inner shielding layer (05); a radioactive source core (03) is disposed inside the outer shell (04) of the radioactive source core, with a second gap (02) between the radioactive source core (03) and the outer shell (04) of the radioactive source core; The outer shielding layer and the inner shielding layer are arranged alternately at intervals; The first gap (01) between the inner shielding layer (05) and the outer shell of the radioactive source core (04) is 0.5 mm to 2 mm.

2. The nuclear battery shielding structure according to claim 1, characterized in that, The outer shell (04) of the radioactive source core is made of a double-layered Hastelloy alloy.

3. The nuclear battery shielding structure according to claim 1, characterized in that, The thickness of the outer shell (04) of the radioactive source core is 1mm to 3mm.

4. The nuclear battery shielding structure according to claim 1, characterized in that, The material used to make the inner shielding layer (05) includes platinum or gold.

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

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

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

8. A nuclear battery, characterized in that, Includes the nuclear battery shielding structure as described in any one of claims 1 to 7.

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