Novel spacecraft radiation shielding structure

Abstract

The invention relates to a novel spacecraft radiation shielding structure, and relates to the field of radiation protection, the novel spacecraft radiation shielding structure comprises two outer layers formed by tungsten aluminum alloy and an inner layer formed by combining metal hydride and boron carbide, the two outer layers are separately arranged on the two sides of the inner layer, and the inner layer is powdery. And the shielding protection requirement of the spacecraft is met.

Description

Technical Field

[0001] The present invention relates to the field of radiation protection technology, and in particular to a novel radiation shielding structure for spacecraft. Background Art

[0002] With the rapid development of the aerospace industry, people are exploring the space more and more deeply. The long flight time and high power of the space mission make the space nuclear reactor power supply (referred to as "space reactor power supply") have the characteristics of high output power, long working life and strong environmental adaptability. It has become the preferred power source for future space exploration missions.

[0003] However, the space reactor power supply needs to strictly limit the volume size and overall mass, and faces harsh radiation environment and high temperature conditions, which puts high demands on the shielding structure of the space reactor. In order to solve the problems of weight, thickness and shielding performance of the shielding structure, it is necessary to continuously optimize the design of the shielding structure.

[0004] Therefore, in view of the above shortcomings, it is necessary to provide a new type of spacecraft radiation shielding structure. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is to solve the problem that the current shielding structure has a large volume and mass and cannot shield neutrons and gamma rays at the same time.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the present invention provides a new type of spacecraft radiation shielding structure, including two outer layers composed of tungsten aluminum alloy and an inner layer composed of metal hydride and boron carbide, the two outer layers are arranged on both sides of the inner layer, and the inner layer is in powder form.

[0009] As a further illustration of the present invention, preferably, the inner layer is a combination powder of lithium hydride and boron carbide.

[0010] As a further illustration of the present invention, preferably, the thickness of the outer layer is 5 mm and the thickness of the inner layer is 50 mm.

[0011] As a further illustration of the present invention, preferably, the ratio of tungsten content to aluminum alloy content in the outer layer is 9:1.

[0012] (III) Beneficial effects

[0013] The above technical solution of the present invention has the following advantages:

[0014] The present invention designs a high-performance shielding structure for a space nuclear reactor power supply, realizes neutron / gamma ray shielding integration, and can meet the shielding requirements of a space nuclear reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural diagram of the present invention;

[0016] Figure 2 This is a comparative analysis diagram of the structure with and without auxiliary detectors;

[0017] Figure 3 This is a schematic diagram of the Geant4 model of neutron shielding performance.

[0018] In the figure: 1. Outer layer; 2. Inner layer; 3. Neutron source; 4. Boron-containing polyethylene plate; 5. Sample; 6. Detector. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution 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 part of the embodiments of the present invention, not all of the embodiments. 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.

[0020] A new type of spacecraft radiation shielding structure, such as Figure 1 As shown, it includes two outer layers 1 made of tungsten aluminum alloy and an inner layer 2 composed of metal hydride and boron carbide. The two outer layers 1 are arranged on both sides of the inner layer 2. The outer layer 1 is preferably 5 mm thick. The inner layer 2 is in powder form and preferably uses lithium hydride (LiH) and boron carbide (B 4 C) of the combined powder, the inner layer 2 preferably has a thickness of 50 mm.

[0021] Combination Figure 1 , Figure 2 The metal tungsten in the outer layer 1 has a good gamma-ray shielding effect, and compared with lead, tungsten has the characteristics of non-toxicity, high hardness, and no secondary bremsstrahlung. Aluminum-based alloys have been widely used in the aerospace field in recent years. In tungsten-aluminum alloys, the tungsten content affects the gamma shielding effect. When the tungsten content is high, the gamma shielding performance is high, which can improve the mechanical properties of the material. Therefore, tungsten-containing alloys can be used for space reactor shielding protection. When the tungsten content is 90% and the aluminum alloy is 10%, it can not only ensure a higher gamma shielding performance, but also improve the mechanical properties of the material, so it can be used for spacecraft shielding protection.

[0022] like Figure 1 As shown, inner layer 2 is selected as LiH+B 4C combination, LiH can slow down neutrons well and absorb thermal neutrons, while B 4 C has a very high thermal neutron absorption cross section. The choice of neutron shielding materials is to contain a certain number of elements with medium or higher atomic numbers and an appropriate amount of light elements, especially hydrogen. Hydrides generated by the reaction of hydrogen and metals, such as lithium hydride, titanium hydride, zirconium hydride, etc., have a high hydrogen density. The density of stored hydrogen exceeds that of liquid hydrogen neutrons, and it has strong neutron shielding ability and good physical and chemical stability at high temperatures. It can effectively reduce the mass and volume of neutron shielding bodies, making it an important candidate shielding material for small modular compact nuclear reactors and space nuclear reactors. The element B has a very high thermal neutron absorption cross section, so it is also an important neutron shielding material.

[0023] In order to verify the shielding effect of the present invention, samples 5 made of various shielding materials were selected for testing. Figure 3 As shown, the test equipment is as follows:

[0024] The 252Cf neutron source 3 is placed in a lead box with three layers of boron-containing polyethylene sheets 4. The source box has a cylindrical opening at one end facing the detector 6. The neutron detector 6 is a 3He proportional counter tube. It is placed 50 cm away from the source, facing the opening of the source box. The sample 5 is located between the source and the counter tube, close to the opening of the source box. Through the test, it can be seen that the shielding rates of various shielding materials are shown in the following table:

[0025] Material Shielding rate / % <![CDATA[B 4 C]]> 74.5 HkD 77..3 <![CDATA[TiH 2 ]]> 80.9 Zirconium zirconate 73.6 LiH+Stainless Steel 70.3 <![CDATA[TiH 2 +B 4 C]]> 85.9 <![CDATA[ZnH 2 +B 4 C]]> 78.9 <![CDATA[LiH+B 4 C]]> 82.4

[0026] The structure of the present invention protects neutrons in two steps: first, deceleration by hydrogen-containing substances, and then absorption by neutron absorbers. 2 +B 4 C has higher neutron shielding performance, but due to TiH 2 The thermal stability is not very good, so the neutron shielding material combination is LiH+B 4 C is the best.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A novel spacecraft radiation shielding structure, characterized in that: The invention comprises two outer layers (1) made of tungsten aluminum alloy and an inner layer (2) composed of metal hydride and boron carbide. The two outer layers (1) are arranged on both sides of the inner layer (2). The inner layer (2) is in powder form.

2. A novel spacecraft radiation shielding structure according to claim 1, characterized in that: The inner layer (2) is a combination powder of lithium hydride and boron carbide.

3. A novel spacecraft radiation shielding structure according to claim 2, characterized in that: The thickness of the outer layer (1) is 5 mm, and the thickness of the inner layer (2) is 50 mm.

4. A novel spacecraft radiation shielding structure according to claim 3, characterized in that: The ratio of tungsten content to aluminum alloy content in the outer layer (1) is 9:1.

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