Reactor reflective layer, method for manufacturing same, and

Abstract

The embodiment of the invention relates to the field of reactor core structure parts, in particular to a reflecting layer of a reactor, a manufacturing method of the reflecting layer and the reactor. The reflecting layer of the reactor provided by the embodiment of the invention adopts the diamond particles as a reflecting material, and because the density of diamond is larger than that of materials such as graphite, the neutron absorption cross section is small, and the neutron reflection effect is better; and meanwhile, the density is lower than that of common metal, the total mass is lighter, the lightweight level is good, and the miniaturization level of a reactor is improved. According to the method for manufacturing the reflecting layer, the diamond particles in the containing cavity are vibrated according to the preset vibration frequency and vibration amplitude, compact filling is achieved, and the neutron reflection effect is enhanced. The reactor provided by the embodiment of the invention comprises the reflecting layer, and the reactor has a better neutron reflecting effect, so that the critical mass of the reactor can be reduced, nuclear fuel can be saved, the descending speed of neutron proliferation factors can be slowed down, and the reactor can stably run for a long time.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of core structural components, and in particular to a reflective layer of a reactor, a manufacturing method thereof, and a reactor. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] The reflector in the reactor is used to reflect the neutrons leaking from the core and reflect some of the escaping neutrons back to the reaction area so that they can continue to participate in the nuclear reaction. The reflective effect of the reflector depends on the material used. The specific influencing factors include the material's density, scattering ability, scattered neutron angle distribution, and absorption cross section. Summary of the invention

[0004] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0005] One aspect of an embodiment of the present application provides a reflective layer of a reactor, which includes: a reflective layer body component and diamond particles. The reflective layer body component is configured to form a sealed accommodating cavity, and the diamond particles are configured to be filled into the accommodating cavity.

[0006] Another aspect of an embodiment of the present application provides a method for manufacturing a reflective layer of the aforementioned reactor, which includes the following steps: preparing a reflective layer body component and forming an open receiving cavity, mixing diamond particles of a predetermined size and proportion; filling the receiving cavity with diamond particles; vibrating the receiving cavity at a predetermined vibration frequency and vibration amplitude to densely fill the diamond particles; and sealing the receiving cavity.

[0007] Yet another aspect of the embodiments of the present application provides a reactor, which includes the aforementioned reflective layer.

[0008] The reflective layer of the reactor provided in the embodiment of the present application uses diamond particles filled into the accommodating cavity of the main body component as a reflective material. Since diamond has a higher density than materials such as graphite and a smaller absorption cross-section for neutrons, the reflective layer has a better reflection effect on neutrons; at the same time, its density is lower than that of ordinary metals, and its total mass as a reflective layer is lighter, so the lightweight level is good, which can improve the miniaturization level of the reactor.

[0009] The manufacturing method of the reflective layer provided in the embodiment of the present application can realize the preparation of the aforementioned reflective layer, and the diamond particles in the accommodating cavity are vibrated according to a predetermined vibration frequency and vibration amplitude, so that the gaps between diamond particles of different particle sizes are reduced, dense filling is achieved, and gaps and holes in the reflective layer are prevented, neutron leakage is reduced, and the neutron reflection effect is enhanced.

[0010] The reactor provided in the embodiment of the present application includes the aforementioned reflective layer, and its better neutron reflection effect can reduce the critical mass of the reactor, save nuclear fuel, slow down the rate of decrease of the neutron multiplication factor, and enable the reactor to operate stably for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to further illustrate the above and other advantages and features of the present application, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings together with the following detailed description are included in this specification and form a part of this specification. Elements with the same function and structure are represented by the same reference numerals. It should be understood that these drawings only describe typical examples of the present application and should not be regarded as limiting the scope of the present application.

[0012] Figure 1 is a schematic diagram of the structure of a reflective layer provided in an embodiment of the present application;

[0013] Figure 2 It is a schematic diagram of mixing diamond particles of two particle sizes provided in an embodiment of the present application;

[0014] Figure 3 It is a schematic diagram of the effective proliferation factor of the core of the reflective layer of different materials provided in the embodiment of the present application;

[0015] Figure 4 It is a schematic diagram of the relationship between the filling rate and the vibration frequency provided in the embodiment of the present application.

[0016] Description of reference numerals:

[0017] 1. Fasteners; 2. Reflection layer cover; 3. Cavity; 4. Reflection layer outer shell; 5. Reflection layer inner shell; 6. Diamond particles; 7. Core effective proliferation factor curve; 701. Core effective proliferation factor of stainless steel reflective layer; 702. Core effective proliferation factor of graphite reflective layer; 703. Core effective proliferation factor of beryllium reflective layer; 704. Core effective proliferation factor of reflective layer with diamond filling rate of 90%; 705. Core effective proliferation factor of reflective layer with diamond filling rate of 100%. DETAILED DESCRIPTION

[0018] Exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the content of this application.

[0019] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0020] The disclosure below provides a plurality of different embodiments or examples to implement the present application. In order to simplify the disclosure of the present application, the parts and methods of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the present application. In the description of the embodiments of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0021] At present, commonly used reflective layer materials include water, graphite, stainless steel, beryllium, beryllium oxide, etc. Among them, the absorption cross section of graphite is very low, and it has very excellent neutron physical properties, but its scattering cross section is also very low. The use of graphite reflective layer usually requires a large volume, which is not suitable for small reactors; water has a strong moderation ability, but it has large harmful absorption of neutrons, and the anisotropy of neutron scattering is poor, so neutrons cannot be effectively reflected back to the core; stainless steel has average reflective ability and is heavy, which is not conducive to reactor miniaturization; beryllium or beryllium oxide has better reflection and moderation performance, but its price is usually high. Therefore, a more cost-effective material is needed as a reflective layer to take into account the needs of reactor neutron economy and reactor miniaturization.

[0022] One aspect of an embodiment of the present application provides a reflective layer of a reactor, which includes: a reflective layer body component and diamond particles. The reflective layer body component is configured to form a sealed accommodating cavity, and the diamond particles are configured to be filled into the accommodating cavity.

[0023] The reflective layer of the reactor provided in the embodiment of the present application uses diamond particles filled into the accommodating cavity of the main body component as a reflective material. Since diamond has a higher density than materials such as graphite and a smaller absorption cross-section for neutrons, the reflective layer has a better reflection effect on neutrons; at the same time, its density is lower than that of ordinary metals, and its total mass as a reflective layer is lighter, so the lightweight level is good, which can improve the miniaturization level of the reactor.

[0024] In some embodiments, the diamond particles are arranged to be densely packed into the receiving cavity.

[0025] In some embodiments, existing industrial diamonds are all in particle form. Since diamonds have the properties of high hardness, great brittleness, and low ignition point, their processing is more difficult, so diamond particles can only be directly filled into the receiving cavity. However, the theoretical filling rate of diamond particles of a single particle size should not exceed 70%, so it is necessary to ensure that the diamond particles can densely fill the receiving cavity.

[0026] Figure 2 Schematic diagram of mixing diamond particles of two particle sizes provided in the embodiments of the present application. In some embodiments, Figure 2 As shown, the diamond particles have different particle sizes, and the diameter ratio between adjacent diamond particles is greater than a first predetermined value, and the total volume ratio between adjacent diamond particles is a second predetermined value.

[0027] The particle size range of diamonds spans a wide range, and since the theoretical filling rate of the diamond particles of the aforementioned single particle size should not exceed 70%, two or more diamond particles of different particle sizes are required to fill the accommodating cavity.

[0028] In some embodiments, it is assumed that there are N different sizes of diamond particles, and the diameters of the diamond particles are D1, D2, ..., D N , the ratio of the diameters of adjacent particles is the first predetermined value, which should be greater than 10 times, that is, D1 / D2>10, D2 / D3>10, D N-1 / D N >10, so that the size difference of the selected diamond particles is kept at a high level, so that the smaller diamond particles can fill the gaps between the larger diamond particles, ensuring that the overall density of the reflective layer is maintained at a uniform level and fully reflecting the escaped neutrons.

[0029] In some embodiments, it is assumed that there are N different sizes of diamond particles, and the total volume of diamond particles of each size is V1, V2, ..., V N , the ratio of the total volume of diamond particles of adjacent sizes is a second predetermined value, which is about 7:3, that is, V1 / V2≈7 / 3, V2 / V3≈7 / 3, V N-1 / VN ≈7 / 3, so that the space in the cavity of the reflective layer body component is mainly filled with diamonds with larger particle sizes, and the gaps are filled with diamond particles with smaller particle sizes, thereby enhancing the compressive resistance inside the diamond particle pile to ensure the overall reflective performance of the diamond reflective layer.

[0030] Figure 1 Schematic diagram of the structure of the reflective layer provided in the embodiment of the present application is shown. In some embodiments, Figure 1 As shown, the reflective layer body assembly includes a reflective layer shell and a reflective layer cover 2. The reflective layer shell is configured to be sealed and connected with the reflective layer cover 2 to form a receiving cavity. The diamond particles 6 are configured to be filled into the receiving cavity.

[0031] In some embodiments, the reflective layer shell is used to load diamond particles and provide the necessary structural strength. The reflective layer shell and the reflective layer cover 2 are fixed by fasteners 1 to seal the reflective layer shell filled with diamond particles, so as to put the reactor to reflect neutrons. In some embodiments, the reflective layer shell can be set in shape according to actual needs, for example, a cube, a sector column or a hexagonal prism.

[0032] In some embodiments, when the diamond particles 6 are filled, the filling position thereof is arranged to leave a predetermined distance from the reflective layer cover 2 to form a cavity 3, and the cavity 3 is filled with an inert gas.

[0033] In some embodiments, since diamond has a low ignition point, the high temperature in the reactor easily causes diamond to react with oxygen in the air, so an inert environment needs to be maintained in the receiving cavity formed by the body component, that is, an inert gas needs to be filled in the receiving cavity to maintain the stability of the diamond particles. The diamond particles used for filling have multiple particle sizes. In the initial filling stage of diamond particles, the stacking height of diamond particles is higher than the final dense diamond particle stacking height. Because inert gas needs to be filled in the receiving cavity, a certain space needs to be reserved in the initial filling stage.

[0034] In some embodiments, the reflective layer shell includes a reflective layer outer shell 4 and a reflective layer inner shell 5. The reflective layer outer shell 4 and the reflective layer inner shell 5 are configured to be sealed and connected to the reflective layer cover 2 to form a accommodating cavity; the reflective layer inner shell 5 is configured to be nested in the reflective layer outer shell 4 and configured to contact the diamond particles 6.

[0035] In some embodiments, the outer shell 4 of the reflective layer is set to a stainless steel structure, and the inner shell 5 of the reflective layer is set to a thin layer structure. A non-ferrous metal material with a high melting point, such as copper, can be used. Copper has a high melting point and can adapt to most types of reactor operating conditions. Copper does not chemically react with diamond and stainless steel, and has good compatibility. The inner shell 5 of the reflective layer made of copper is used to isolate the diamond particles 6 from the outer shell 4 of the reflective layer to prevent chemical reactions under high temperature conditions; and copper has a high thermal conductivity, and the diamond particles also have a high thermal conductivity, and the entire reflective layer can be cooled from the outside without setting cooling channels inside; copper has high ductility and good processability, and can meet the requirement that the inner shell 5 of the reflective layer is a thin layer structure.

[0036] In some embodiments, Figure 1 As shown, the vertical height of the reflective layer inner shell 5 is set to be lower than the height of the reflective layer outer shell 4, so that a stepped height difference is formed between the reflective layer inner shell 5 and the reflective layer outer shell 4. Correspondingly, the reflective layer cover 2 is set to a shape matching the stepped reflective layer shell to increase the contact area and achieve a better sealing effect.

[0037] In some embodiments, the thickness of the reflective layer outer shell 4 is greater than the thickness of the reflective layer inner shell 5 to make the structure stronger.

[0038] In some embodiments, the maximum diameter of the diamond particles is D1, and the minimum length, width and height of the outline envelope formed by all the diamond particles is D r , D r / D1 is greater than a predetermined value.

[0039] In some embodiments, D r / D1 is greater than 10, so that the diamond particles with the largest particle size are smaller than the internal size of the accommodating cavity, preventing the diamond particles from being too large, resulting in too large a gap left at the boundary, thereby reducing the boundary effect and achieving a higher filling rate.

[0040] Another aspect of an embodiment of the present application provides a method for manufacturing the aforementioned reflective layer, which includes the following steps: preparing a reflective layer body component and forming an open receiving cavity, mixing diamond particles of a predetermined size and proportion; filling the receiving cavity with diamond particles; vibrating the receiving cavity according to a predetermined vibration frequency and vibration amplitude to densely fill the diamond particles; and sealing the receiving cavity.

[0041] The manufacturing method of the reflective layer of the reactor provided in the embodiment of the present application can realize the preparation of the aforementioned reflective layer, and the diamond particles in the containing cavity are vibrated according to a predetermined vibration frequency and vibration amplitude, so that the gaps between diamond particles of different particle sizes are reduced, dense filling is achieved, and gaps and holes in the reflective layer are prevented, neutron leakage is reduced, and the neutron reflection effect is enhanced.

[0042] In some embodiments, the reflective layer inner shell 5 and the reflective layer outer shell 4 need to be processed according to the required size and shape, and the upper opening is retained for filling diamond particles; the particle size of diamond particles is determined according to the standard that the ratio of the diameters of diamond particles of adjacent sizes is greater than 10 and the ratio of the total volume of diamond particles of adjacent sizes is 7:3; the selected diamond particles are preliminarily mixed to prevent small-sized diamond particles from being unable to fill the gaps; the mixed diamond particles are filled into the reflective layer shell, and the reflective layer shell filled with diamond particles is placed as a whole on a dedicated three-dimensional vibration platform for vibration compaction; the reflective layer cover 2 is installed and fixed with fasteners 1 to achieve the packaging of the reflective layer shell.

[0043] Figure 4 A schematic diagram showing the relationship between the filling rate and the vibration frequency provided by the embodiments of the present application. In some embodiments, the vibration amplitude is selected to be close to the minimum particle size of the diamond particles, such as Figure 4 As shown in the figure, the filling rate changes with the vibration frequency and shows a characteristic of first rising and then falling, with a maximum point. When the vibration frequency is low, increasing the vibration frequency can rearrange the particles and fill the large pores to make the diamond particles denser as a whole, while too high a vibration frequency will destroy the already formed tight stacking.

[0044] Yet another aspect of the embodiments of the present application provides a reactor, which includes the aforementioned reflective layer.

[0045] The reactor provided in the embodiment of the present application includes the aforementioned reflective layer, and its better neutron reflection effect can reduce the critical mass of the reactor, save nuclear fuel, slow down the rate of decrease of the neutron multiplication factor, and enable the reactor to operate stably for a long time.

[0046] The effective core multiplication factor indicates the multiplication of neutrons in the reactor. When the effective core multiplication factor is greater than 1, it means that the number of neutrons in the reactor is increasing and the reactor is in a supercritical state. When the effective core multiplication factor is equal to 1, it means that the number of neutrons remains unchanged and the reactor is in a critical state. When the effective core multiplication factor is less than 1, it means that the number of neutrons is decreasing and the reactor is in a subcritical state. An efficient reflector can significantly improve the utilization rate of neutrons and the efficiency of the reactor, thereby improving the effective core multiplication factor. Therefore, the performance of the reflector material can be characterized by the effective core multiplication factor.

[0047] In some embodiments, a typical small reactor is selected to carry out calculation of the effective proliferation factor of the core under different material reflector environments, wherein stainless steel, graphite, beryllium, diamond with a filling rate of 90%, and diamond with a filling rate of 100% equivalent to different carbon element densities are selected as the core reflector, and the effective proliferation factor of the core under corresponding conditions is calculated. Figure 3A schematic diagram showing the effective proliferation factor of the core of the reflective layer of different materials provided in the embodiments of the present application. In some embodiments, Figure 3 As shown, on the core effective proliferation factor curve 7, the value of the core effective proliferation factor 701 of the stainless steel reflector layer is about 0.985; the value of the core effective proliferation factor 702 of the graphite reflector layer is slightly greater than the value of the core effective proliferation factor 701 of the stainless steel reflector layer and less than 0.99; the value of the core effective proliferation factor 703 of the beryllium reflector layer is between 1.00 and 1.01; the value of the core effective proliferation factor 704 of the reflector layer with a diamond filling rate of 90% is about 1.02; the value of the core effective proliferation factor 705 of the reflector layer with a diamond filling rate of 100% is greater than 1.02. In summary, the reflector layer with a diamond filling rate of 90% can achieve a reactivity value exceeding 1700pcm of the beryllium reflector layer, indicating that the diamond reflector layer has a better reflection effect.

[0048] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0049] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A reflector layer of a reactor, characterized in that: It includes: Reflection layer body components, diamond particles, The reflective layer body assembly is configured to form a sealed accommodating cavity. The diamond particles are configured to be filled into the accommodating cavity.

2. The reflective layer according to claim 1, characterized in that: The diamond particles are arranged to be densely filled into the accommodating cavity.

3. The reflective layer according to claim 2, characterized in that: The diamond particles have different particle sizes, and a diameter ratio between adjacent diamond particles is greater than a first predetermined value, and a total volume ratio between adjacent diamond particles is a second predetermined value.

4. The reflective layer according to claim 1, characterized in that: The reflective layer body assembly comprises a reflective layer shell and a reflective layer cover. The reflective layer housing is configured to be sealed and connected to the reflective layer cover to form the accommodating cavity. The diamond particles are configured to be filled into the accommodating cavity.

5. The reflective layer according to claim 4, characterized in that: When the diamond particles are filled, the filling position is arranged to leave a predetermined distance from the reflective layer cover to form a cavity, and the cavity is filled with an inert gas.

6. The reflective layer according to claim 4, characterized in that: The reflective layer housing comprises a reflective layer outer shell and a reflective layer inner shell, wherein the reflective layer outer shell and the reflective layer inner shell are configured to be sealed and connected with the reflective layer cover to form the accommodating cavity; The inner reflective layer shell is arranged to be nested in the outer reflective layer shell and to be in contact with the diamond particles.

7. The reflective layer according to claim 6, characterized in that: The thickness of the outer shell of the reflective layer is greater than the thickness of the inner shell of the reflective layer.

8. The reflective layer according to any one of claims 1 to 7, characterized in that: The maximum diameter of the diamond particles is D1, and the minimum length, width and height of the outline envelope formed by all diamond particles is D r , D r / D1 is greater than a predetermined value.

9. A method for manufacturing the reflective layer according to any one of claims 1 to 8, characterized in that: It includes the following steps: Prepare a reflective layer body component and form an open receiving cavity, Mixing diamond particles of predetermined sizes and proportions; Filling the diamond particles into the containing cavity; Vibrating the containing cavity according to a predetermined vibration frequency and vibration amplitude so as to densely fill the diamond particles; The accommodating cavity is sealed.

10. A reactor, characterized in that: It comprises the reflective layer according to any one of claims 1 to 8.

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