A double-stranded biomimetic radiation shielding structure and method of manufacture thereof

Abstract

This invention discloses a double-stranded biomimetic radiation shielding structure and its manufacturing method, comprising a plurality of shielding units arranged in an array. Each shielding unit includes a first single strand for absorbing gamma rays, a second single strand for absorbing neutrons, and a shell for supporting and slowing down neutrons. The first and second single strands are helically wound according to a double-stranded DNA helix structure to form a cylindrical core. The shell wraps around the outside of the core, making the outer shape of the shielding unit a regular prismatic shape. This invention designs a lightweight and efficient polymer-based radiation shielding structure capable of slowing down and timely absorbing neutrons and gamma rays in all directions, and proposes an additive manufacturing method adapted to this shielding structure, ensuring its feasibility in principle and its manufacturability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear radiation shielding design, in particular to a double-chain biomimetic radiation shielding structure and a manufacturing method thereof. BACKGROUND

[0002] Nuclear energy is a safe, clean, low-carbon, high-energy-density strategic energy. In order to cope with the environmental and energy crisis, each country attaches more and more importance to the development and utilization of nuclear energy, and advanced new reactors are constantly being developed. Safety is one of the key issues that need to be considered for nuclear energy. Advanced new reactors (such as small mobile reactors) often require high-performance shielding and lighter weight. Traditional shielding methods such as concrete walls and lead often cannot meet the requirements, so it is a good way to solve the problem of heavy and poor shielding performance of traditional radiation shielding structures by selecting lightweight materials (such as polymer-based materials) and designing efficient radiation shielding structures to shield various rays generated from the reactor.

[0003] The rays from the reactor include alpha, beta, gamma rays and neutron flow, among which gamma rays and neutron flow have strong penetration ability and are the main rays that need to be considered for shielding. A large number of studies have found that using a multi-level structure and timely slowing down, absorbing neutrons and gamma rays is beneficial to improving the radiation shielding performance. However, the movement of the rays in the radiation is random, and the traditional multi-layer structure can only achieve timely neutron slowing down and absorption and gamma ray absorption in the normal direction of the layers in the multi-level structure. If there is a multi-level structure in the parallel direction, the randomly moving rays can experience more levels of radiation shielding and thus improve the radiation shielding performance. Therefore, how to design a material and structure that can timely slow down, absorb neutrons and absorb gamma rays in all directions is an effective method to improve the radiation shielding ability. SUMMARY

[0004] The purpose of the present application is to provide a double-chain biomimetic radiation shielding structure and a manufacturing method thereof to solve the problems of low shielding efficiency and heavy structure of traditional radiation shielding structures. The present application designs a lightweight and efficient polymer-based radiation shielding structure that can slow down and timely absorb neutrons and gamma rays in all directions, and proposes an additive manufacturing method suitable for the shielding structure, which ensures that it is feasible in principle and can be manufactured.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A double-stranded biomimetic radiation shielding structure includes several shielding units arranged in an array. Each shielding unit includes a first single strand for absorbing gamma rays, a second single strand for absorbing neutrons, and a shell for supporting and slowing down neutrons. The first and second single strands are spirally wound according to the double-stranded DNA helix structure to form a cylindrical core. The shell wraps around the outside of the core, making the outer shape of the shielding unit a regular prismatic shape.

[0007] Furthermore, the cross-sections of both the first and second single chains are semi-circular.

[0008] Furthermore, the casing is a structure that allows adjacent shielding units to be arranged in surface contact.

[0009] Furthermore, the shell is a square prism or a hexagonal prism, and the center of the square prism or hexagonal prism is a hollow cylinder that matches the core.

[0010] Furthermore, the first single chain uses polyethylene as the matrix material and lead, tungsten, or bismuth as the radiation shielding enhancement phase material.

[0011] Furthermore, the second single chain uses polyethylene as the matrix material and boron carbide, boron nitride, or gadolinium oxide as the radiation shielding enhancement phase material.

[0012] Furthermore, the shell uses polyetheretherketone as the matrix material and tungsten or bismuth as the radiation shielding enhancement phase material.

[0013] A method for manufacturing a double-chain biomimetic radiation shielding structure includes the following steps:

[0014] Step 1: Draw the configuration of the double-chain biomimetic radiation shielding structure using 3D software, and process the model data using 3D printing slicing software;

[0015] Step 2: Prepare various composite filaments for 3D printing based on the different functions of the core and shell;

[0016] Step 3: Based on the processed data obtained in Step 1 and the composite material filaments prepared in Step 2, the core and shell are printed simultaneously using a multi-nozzle 3D printing device to realize the layered solid manufacturing of the double-chain biomimetic radiation shielding structure.

[0017] Furthermore, the multi-nozzle 3D printing equipment includes a plurality of 3D printing nozzles, each of which includes a 3D printing nozzle filament feed wheel, a 3D printing nozzle throat, a 3D printing nozzle heating block, and a 3D printing nozzle.

[0018] The composite material filament for 3D printing is fed into the throat of the 3D printing nozzle through the filament feeding wheel of the 3D printing nozzle. The throat of the 3D printing nozzle is equipped with a 3D printing nozzle heating block for heating and melting the composite material filament for 3D printing. The outlet end of the throat of the 3D printing nozzle is connected to the 3D printing nozzle.

[0019] Furthermore, the composite material filament for 3D printing includes a first composite material filament, a second composite material filament, and a third composite material filament;

[0020] The first composite material filament uses polyethylene as the matrix material and lead, tungsten or bismuth as the radiation shielding reinforcement phase material;

[0021] The second composite material filament uses polyethylene as the matrix material and boron carbide, boron nitride, or gadolinium oxide as the radiation shielding reinforcement phase material;

[0022] The third composite material filament uses polyetheretherketone as the matrix material and tungsten or bismuth as the radiation shielding reinforcement phase material.

[0023] Compared with the prior art, the present invention has the following beneficial technical effects:

[0024] The radiation shielding structure designed in this invention is lightweight and highly efficient. It can be integrally formed through additive manufacturing, and its advantages are specifically reflected in the following aspects:

[0025] Compared to traditional shielding structures made of materials such as concrete, stainless steel, and lead, this invention achieves graded and efficient shielding. Through a graded absorption process involving slowing and absorption, it achieves better radiation absorption and is highly efficient. The choice of matrix material also makes it lightweight. Compared to radiation shielding structures made of a single polymer matrix material, this invention, due to the high hydrogen content of the core and the high mechanical properties of the shell, achieves a balance between hydrogen content and mechanical properties, making it suitable for use as a structural component and providing strong neutron slowing effects. Compared to radiation shielding structures with a multi-layered shielding design (containing slowing and absorption layers), this invention's design ensures that, at the same thickness, radiation rays, regardless of their direction or motion, will pass through the interface at least once or even multiple times (compared to the original design which only passes through the interface once), achieving multiple slowing and absorption effects. This results in more efficient radiation shielding at the same thickness.

[0026] Furthermore, the structure designed in this invention is complex and difficult to manufacture using traditional methods. Therefore, this invention adopts a 3D printing manufacturing method to achieve integrated molding of the structure, which has the characteristics of short manufacturing cycle and low cost. Attached Figure Description

[0027] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0028] Figure 1 The diagram shows the shielding unit structure of the present invention. (a) is a quadrangular prism shell structure, and (b) is a hexagonal prism shell structure.

[0029] Figure 2 This is a schematic diagram of the core structure in the shielding unit of the present invention;

[0030] Figure 3 This is a schematic diagram of the quadrangular prism shell structure in the shielding unit of the present invention;

[0031] Figure 4 a is Figure 1 A schematic diagram of the shielding process of horizontally moving rays by the shielding structure in the middle AA section and the shielding structure under this section;

[0032] Figure 4 b is Figure 1 A schematic diagram of the shielding process of horizontally moving rays by the shielding structure at the BB horizontal section and below the section;

[0033] Figure 5 for Figure 1 A schematic diagram of the shielding process of horizontally moving rays by the shielding structure under the middle CC vertical section;

[0034] Figure 6 This is a schematic diagram of the 3D printing (FDM) of the double-chain biomimetic radiation shielding structure of the present invention.

[0035] In the figure, 1. First single chain; 2. Second single chain; 3. Shell; 4. 3D printing nozzle; 5. 3D printing nozzle heating block; 6. 3D printing nozzle throat; 7. 3D printing nozzle filament feed wheel; 8. First composite filament; 9. Second composite filament; 10. Third composite filament. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0038] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0039] The design concept of the double-chain biomimetic radiation shielding structure of this invention is as follows:

[0040] Based on the arrangement of the DNA double helix structure in the biological world, the characteristic of double strands is that both strands can pass through the double helix structure in any direction. This provides a design concept for a shielding structure capable of slowing down and timely absorbing neutrons and gamma rays in all directions, as described in this invention. Specifically, one single strand is used for neutron slowing and gamma ray absorption, while the other single strand is used for neutron absorption. The key feature of this design is that when rays pass through the shielding structure from different directions, they will all pass through both single strands of the double helix, thus achieving a graded radiation shielding process from slowing down to absorption.

[0041] Based on the above design concept, it was determined that a structure with a semi-circular cross-section would be used as a single chain of a double helix, and the double chains would be wound together to form a cylinder as the core. The final shielding structure would be composed of the core evenly arranged.

[0042] Because the uniformly arranged cylinders are in tangential line contact, the resulting shielding structure has many pores. Further optimization is needed to eliminate these pores. The optimized shielding unit is a core-shell structure. The core uses a double-helix structure to primarily achieve radiation shielding in all directions. The shell uses square prisms (not limited to square prisms; hexagonal prisms, etc., arranged in surface contact) primarily to eliminate structural pores and serve as a support and radiation absorption structure.

[0043] The aforementioned design configuration was manufactured using 3D printing. First, the configuration was drawn using 3D software, and the model data was processed using 3D printing slicing software. Furthermore, various 3D printing-specific materials were prepared based on the different functions of the core double chains and the shell. Finally, using the obtained data and the prepared materials, a multi-nozzle 3D printing machine was used to simultaneously print the core and shell models with complex multi-material configurations, achieving the layered solid fabrication of this shielding structure.

[0044] This invention discloses a biomimetic double-chain radiation shielding structure and its manufacturing method. Its key features are: 1. The use of a double-chain helical core and shell structure, enabling radiation shielding from all directions; 2. The flexibility in material selection for the core and shell allows the radiation shielding structure to possess both strong mechanical properties and high hydrogen content. The shell can be made of a polyetheretherketone (PEEK) matrix material (not limited to PEEK, any resin with good mechanical and heat resistance) as the supporting structure, and gamma-ray absorbers such as tungsten or lead as fillers. The core is made of polyethylene material with good neutron moderation (not limited to polyethylene, any resin with high hydrogen content that can effectively moderate neutrons), and neutron absorbers such as boron carbide and boron nitride, and gamma-ray absorbers such as tungsten and lead are selected as fillers for the two single chains, respectively.

[0045] The shell material of this invention uses a high-performance polymer material (such as polyetheretherketone) to give it good mechanical properties. However, high-performance polymers like polyetheretherketone typically have a low hydrogen content. Furthermore, for current polymers, it is generally difficult to balance hydrogen content and mechanical properties. Therefore, the material system is selected as follows: polyetheretherketone is chosen for the shell to provide overall mechanical properties, and polyethylene is chosen for the core to increase the overall hydrogen content of the structure.

[0046] Example

[0047] This invention provides a double-chain biomimetic radiation shielding structure and its manufacturing method. The radiation shielding structure has good radiation shielding capability and is composed of multiple shielding units. To illustrate the radiation shielding performance of this structure, the shielding process of the shielding units of the radiation shielding structure is first introduced. By understanding the shielding principle of the shielding units, the shielding principle of the entire shielding structure can be understood.

[0048] The shielding unit in this invention is as follows Figure 1 As shown, it consists of a core and a shell 3. The core structure is as follows: Figure 2 As shown, it consists of a first single chain 1 and a second single chain 2; the shell 3 is as follows Figure 3 As shown, its main function is to provide support and prevent structural voids. Various structures can be adopted, such as regular square prisms and regular hexagonal prisms. Figure 1 The two structures shown are illustrated below. For ease of explanation, a regular square prism is used to illustrate the implementation of this invention; other structural shells are similar. The optimized material selection for each part of this shielding unit is as follows:

[0049] The preferred materials for this shielding unit include polyetheretherketone (PEEK), polyethylene (PE), tungsten, bismuth, boron carbide, boron nitride, and gadolinium oxide. PEEK and PE are preferred matrix materials, both being lightweight. PEEK possesses excellent mechanical and heat resistance properties, making it suitable as a structural component to bear loads, and its hydrogen content helps moderate neutrons to a certain extent. PE, with its high hydrogen content, is an excellent neutron moderator, significantly slowing down neutrons. Lead, tungsten, bismuth, boron carbide, boron nitride, and gadolinium oxide are preferred radiation shielding enhancement phases that absorb radiation. Tungsten and bismuth, being heavy elements, primarily absorb gamma rays. Boron in boron carbide and boron nitride has a large neutron absorption cross-section, effectively absorbing neutrons and producing only a small amount of secondary gamma rays. Gadolinium oxide has the largest thermal neutron absorption cross-section among all elements, theoretically possessing the best neutron absorption performance.

[0050] Furthermore, the shell 3 functions to moderate neutrons and absorb some gamma rays to a certain extent. In addition, the shell 3, as a supporting structure, needs to possess certain mechanical properties and high-temperature resistance; preferably, it is made of polyetheretherketone (PEEK) matrix with elements such as tungsten and bismuth, which have high atomic numbers, added to absorb gamma rays.

[0051] Furthermore, the core is formed by a helical winding (double-stranded DNA helical structure) of a first single chain 1 and a second single chain 2 of different shielding materials. It has the functions of better slowing down neutrons, absorbing neutrons, absorbing gamma rays, and absorbing secondary gamma rays generated during the interaction of matter and neutrons. Preferably, the core matrix material is polyethylene, wherein the first single chain 1 mainly plays the role of slowing down neutrons and absorbing gamma rays, and uses polyethylene matrix with added heavy element materials such as tungsten and bismuth as shielding reinforcement phase; the second single chain 2 mainly plays the role of slowing down neutrons and absorbing them, and uses polyethylene matrix with added materials such as boron nitride, boron carbide, and gadolinium oxide as shielding reinforcement phase.

[0052] In summary, by using a polyetheretherketone (PEEK) matrix shell 3, the radiation shielding structure possesses excellent mechanical properties as well as heat and radiation resistance. The double-chain core is made of polyethylene matrix material, which enables the radiation shielding structure to have good neutron moderation capabilities, thereby improving the radiation shielding performance. Furthermore, by selecting the optimal radiation shielding enhancement material, the shielding against neutrons and gamma rays is effectively achieved.

[0053] The shielding principle of the shielding unit in this invention is described below:

[0054] When radiation rays containing gamma rays and neutron flux pass horizontally through the shielding unit, the movement of the rays is random and may continue to move horizontally or vertically. The shielding unit of the present invention can effectively shield and absorb rays from all directions, thereby improving the shielding performance.

[0055] The ray will first pass through the shell 3. When moving horizontally, it can undergo several changes: 1. It passes through the first single chain 1 and then the second single chain 2, exhibiting the characteristic of slowing down neutrons before absorption. The above process is as follows: Figure 4 As shown in a; 2. Passing through the second single chain 2 and then through the first single chain 1, it has the characteristic of absorbing neutrons and then absorbing gamma rays and secondary gamma rays. The specific process is as follows: Figure 4 As shown in b. Similarly, after the ray passes through the casing 3, it also exhibits the two aforementioned situations in the vertical direction, one of which is as follows: Figure 5 As shown, this illustrates the ray shielding process when a ray first penetrates the second single chain 2 and then the first single chain 1; another case can be obtained by analogy with case 1 during horizontal movement. Ultimately, the ray will undergo multi-layered shielding during both horizontal and vertical movement. In summary, the double-chain structure achieves the same effect as the double-layer structure in the horizontal direction, and in the vertical direction, due to the repeated passage through the two single chains during movement, it achieves a better effect than the double-layer structure. The random movement of the ray within the shielding structure can be considered as a superposition of horizontal and vertical movements. Therefore, this structure can provide radiation shielding equal to (along horizontal movement) or greater than (non-horizontal movement) two levels of shielding effect for rays from all directions and for the random movement of rays. Figure 6 The combination of multiple shielding units shown will achieve better radiation shielding performance than traditional multi-level structures. In addition, it also has good mechanical properties, heat resistance and lightweight characteristics.

[0056] Furthermore, arranging smaller radiation shielding units can yield shielding structures for various targets.

[0057] Furthermore, if the above-mentioned target shielding structure is manufactured using... Figure 2 The core and shown Figure 3 The traditional manufacturing method of manufacturing the shell separately and then assembling it is difficult to achieve, so 3D printing is required.

[0058] Furthermore, using multiple 3D printing nozzles, a first composite material filament 8, a second composite material filament 9, and a third composite material filament 10 are respectively used to print the shell 3 and the core (composed of a spiral of a first single chain 1 and a second single chain 2) to achieve the fabrication of the shielding structure. The first composite material filament 8 uses polyethylene as the matrix material and lead, tungsten, or bismuth as the radiation shielding reinforcement phase material; the second composite material filament 9 uses polyethylene as the matrix material and boron carbide, boron nitride, or gadolinium oxide as the radiation shielding reinforcement phase material; the third composite material filament 10 uses polyetheretherketone (PEEK) as the matrix material and tungsten or bismuth as the radiation shielding reinforcement phase material, such as... Figure 6As shown, the composite material filament for 3D printing is fed into the 3D printing nozzle throat 6 through the 3D printing nozzle feed roller 7. The 3D printing nozzle throat 6 is equipped with a 3D printing nozzle heating block 5 for heating and melting the composite material filament for 3D printing. The outlet end of the 3D printing nozzle throat 6 is connected to the 3D printing nozzle 4.

[0059] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A double-chain biomimetic radiation shielding structure, characterized in that, The shielding unit comprises several shielding units arranged in an array. Each shielding unit includes a first single strand (1) for absorbing gamma rays, a second single strand (2) for absorbing neutrons, and a shell (3) for supporting and slowing down neutrons. The first single strand (1) and the second single strand (2) are spirally wound in a double-stranded DNA helical structure to form a cylindrical core. The shell (3) wraps around the outside of the core, making the outer shape of the shielding unit a regular prism. The cross-section of the first single strand (1) and the second single strand (2) is semi-circular. The shell (3) is a structure that allows adjacent shielding units to be arranged in surface contact. The shell (3) is a quadrangular prism or a hexagonal prism, and the center of the quadrangular prism or hexagonal prism is a hollow cylinder that matches the core.

2. The double-chain biomimetic radiation shielding structure according to claim 1, characterized in that, The first single chain (1) uses polyethylene as the matrix material and lead, tungsten or bismuth as the radiation shielding enhancement phase material.

3. The double-chain biomimetic radiation shielding structure according to claim 1, characterized in that, The second single chain (2) uses polyethylene as the matrix material and boron carbide, boron nitride or gadolinium oxide as the radiation shielding enhancement phase material.

4. The double-chain biomimetic radiation shielding structure according to claim 1, characterized in that, The shell (3) uses polyetheretherketone as the matrix material and tungsten or bismuth as the radiation shielding enhancement phase material.

5. A method for manufacturing the double-chain biomimetic radiation shielding structure according to claim 1, characterized in that, Includes the following steps: Step 1: Draw the configuration of the double-chain biomimetic radiation shielding structure using 3D software, and process the model data using 3D printing slicing software; Step 2: Prepare various composite filaments for 3D printing based on the different functions of the core and shell; Step 3: Based on the processed data obtained in Step 1 and the composite material filaments prepared in Step 2, the core and shell are printed simultaneously using a multi-nozzle 3D printing device to realize the layered solid manufacturing of the double-chain biomimetic radiation shielding structure.

6. The manufacturing method of a double-chain biomimetic radiation shielding structure according to claim 5, characterized in that, The multi-nozzle 3D printing equipment includes several 3D printing nozzles, each of which includes a 3D printing nozzle feed wheel (7), a 3D printing nozzle throat (6), a 3D printing nozzle heating block (5), and a 3D printing nozzle (4). The composite material filament for 3D printing is fed into the 3D printing nozzle throat (6) by the 3D printing nozzle feed wheel (7). The 3D printing nozzle throat (6) is provided with a 3D printing nozzle heating block (5) for heating and melting the composite material filament for 3D printing. The outlet end of the 3D printing nozzle throat (6) is connected to the 3D printing nozzle (4).

7. The manufacturing method of a double-chain biomimetic radiation shielding structure according to claim 5, characterized in that, The composite material filaments for 3D printing include a first composite material filament (8), a second composite material filament (9), and a third composite material filament (10). The first composite material filament (8) uses polyethylene as the matrix material and lead, tungsten or bismuth as the radiation shielding reinforcement material; The second composite material filament (9) uses polyethylene as the matrix material and boron carbide, boron nitride or gadolinium oxide as the radiation shielding reinforcement phase material; The third composite material filament (10) uses polyether ether ketone as the matrix material and tungsten or bismuth as the radiation shielding reinforcement phase material.

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