Nuclear fuel dressing particle based on beryllium oxide and preparation method thereof

Abstract

The invention relates to the technical field of nuclear fuel, in particular to beryllium oxide-based nuclear fuel dressing particles and a preparation method thereof. The nuclear fuel dressing particle comprises a nuclear fuel particle and a beryllium oxide layer located on the periphery of the nuclear fuel particle. The nuclear fuel particle comprises a fuel core, a loose pyrolytic carbon layer, an inner compact pyrolytic carbon layer and a carbide layer which are sequentially arranged from inside to outside. According to the nuclear fuel dressing particle, beryllium oxide is coated on the surface of the nuclear fuel particle, so that the problem that the nuclear fuel particle and a beryllium oxide powder material cannot be uniformly mixed due to large density difference is solved, and the distribution uniformity of the nuclear fuel particle in a beryllium oxide matrix material is remarkably improved; and the serious problems of particle breakage, even failure and the like caused by direct contact of the nuclear fuel particles under high pressure in the compression molding process can be effectively avoided, and the safety of the nuclear fuel particles is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of nuclear fuel technology, in particular to a beryllium oxide-based nuclear fuel coating particle and a preparation method thereof. Background Art

[0002] In the nuclear power sector, micro-reactor technology has become an important future development direction. Graphite, used in high-temperature gas-cooled reactors, cannot meet the requirements of micro-reactors due to its weak neutron moderation and susceptibility to oxidation. Compared with graphite, beryllium oxide ceramics offer improved oxidation and corrosion resistance, higher thermal conductivity, stronger neutron moderation, and the ability to induce neutron multiplication. Therefore, they are the preferred moderator, reflector, and fuel pellet matrix materials for micro-reactors.

[0003] The main methods for preparing beryllium oxide ceramics are pressureless sintering and hot pressing. The density of beryllium oxide ceramics prepared by pressureless sintering is somewhat lower than that of hot pressing. As early as the 1960s, some people explored the use of graphite molds to hot press sinter beryllium oxide powder. However, the beryllium oxide ceramics prepared by hot pressing were light gray, indicating that carbon elements diffused into the beryllium oxide ceramics during the sintering process. The existing technology combines the hot pressing sintering process with the decarburization process, and explores the hot pressing and decarburization process conditions corresponding to the preparation of beryllium oxide ceramics with good appearance. At the same time, the coated fuel particles are dispersed into the beryllium oxide matrix containing additives, and nuclear fuel elements are prepared by pressureless sintering and hot pressing sintering respectively. However, the density of the coated fuel particles is much greater than that of the beryllium oxide powder, and the two are difficult to mix evenly. The high pressure during the pressing process may cause the unevenly dispersed coated fuel particles to directly squeeze each other due to contact, thereby causing the coating layer to crack or even the coated fuel particles to break, causing the coated fuel particles to fail. During service, radioactive fission products will diffuse from the coated fuel particles into the environment. Summary of the Invention

[0004] The present invention aims to at least partially address one of the technical problems in the related art. To this end, the present invention provides beryllium oxide-based nuclear fuel-coated particles and a method for preparing the same. By uniformly coating the surface of the nuclear fuel particles with beryllium oxide, the nuclear fuel-coated particles address the problem of uneven mixing between the nuclear fuel particles and the beryllium oxide powder material due to the significant density difference. This significantly improves the uniformity of the distribution of the nuclear fuel particles within the beryllium oxide matrix material and effectively avoids serious problems such as particle fracture and even failure caused by direct contact of the nuclear fuel particles under high pressure during the press molding process, significantly enhancing the safety of the nuclear fuel particles.

[0005] To this end, the first aspect of the present invention provides a beryllium oxide-based nuclear fuel-coated particle, the nuclear fuel-coated particle comprising a nuclear fuel particle and a beryllium oxide layer located on the periphery of the nuclear fuel particle;

[0006] The nuclear fuel particle comprises a fuel core, a loose pyrolytic carbon layer, an inner dense pyrolytic carbon layer and a carbide layer which are arranged in sequence from the inside to the outside.

[0007] The nuclear fuel-coated particles provided by the present invention coat the surface of the nuclear fuel particles with beryllium oxide powder as a coating layer. On the one hand, the nuclear fuel particles can be well protected during compression molding, and on the other hand, the nuclear fuel particles can be more evenly dispersed in the beryllium oxide matrix. The nuclear fuel-coated particles can be directly used to prepare beryllium oxide-based dispersed fuel pellets.

[0008] According to an embodiment of the present invention, the diameter of the nuclear fuel particles is 300 μm-1000 μm.

[0009] According to an embodiment of the present invention, the thickness of the beryllium oxide layer is 100 μm-500 μm.

[0010] According to an embodiment of the present invention, the diameter of the fuel core is 100 μm-900 μm.

[0011] According to an embodiment of the present invention, the thickness of the loose pyrolytic carbon layer is 10 μm-100 μm.

[0012] According to an embodiment of the present invention, the thickness of the inner dense pyrolytic carbon layer is 3 μm-50 μm.

[0013] According to an embodiment of the present invention, the thickness of the carbide layer is 15 μm-50 μm.

[0014] According to an embodiment of the present invention, the material of the fuel core includes at least one of zirconium carbide, tungsten carbide, uranium dioxide, uranium carbide, and uranium nitride.

[0015] According to an embodiment of the present invention, the material of the carbide layer includes at least one of silicon carbide, zirconium carbide, and niobium carbide.

[0016] According to an embodiment of the present invention, the beryllium oxide layer includes beryllium oxide and an additive.

[0017] According to an embodiment of the present invention, the content of the additive in the beryllium oxide layer is 0.5 wt %-5 wt %.

[0018] According to an embodiment of the present invention, the additive includes at least one of silicon dioxide, magnesium oxide, and aluminum oxide.

[0019] A second aspect of the present invention provides a method for preparing the nuclear fuel-coated particles according to the first aspect, the method comprising the following steps:

[0020] mixing beryllium oxide and additives, and granulating to obtain beryllium oxide powder;

[0021] The nuclear fuel particles are placed in a dressing device, and the beryllium oxide powder and ethanol aqueous solution are added into the dressing device to obtain the nuclear fuel dressing particles.

[0022] According to an embodiment of the present invention, the volume ratio of ethanol to water in the ethanol aqueous solution is 1:3-3:1.

[0023] According to an embodiment of the present invention, the preparation method further comprises: placing nuclear fuel particles in a dressing device, adding the beryllium oxide powder and ethanol aqueous solution into the dressing device, and drying to obtain the nuclear fuel dressing particles.

[0024] According to an embodiment of the present invention, the rotation speed of the dressing device is 150 rpm-250 rpm.

[0025] According to an embodiment of the present invention, the drying temperature is 105°C-120°C.

[0026] According to an embodiment of the present invention, the drying time is 2 hours to 4 hours.

[0027] The beneficial effects of the present invention compared to the prior art are as follows:

[0028] The present invention coats nuclear fuel particles with beryllium oxide powder and then directly hot-presses and sinters them to prepare nuclear fuel pellets with different loading amounts. Compared with simply mixing nuclear fuel particles and beryllium oxide powder and then hot-pressing and sintering them, the nuclear fuel pellets prepared by the present invention have more uniform particle distribution inside.

[0029] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0031] Figure 1 The figure shows the morphology of the nuclear fuel-coated particles prepared in Example 1 of the present invention;

[0032] Figure 2 shows the morphology of the nuclear fuel pellets prepared in Example 1 of the present invention;

[0033] Figure 3shows the morphology of the nuclear fuel pellets prepared in Example 2 of the present invention;

[0034] Figure 4 shows the morphology of the nuclear fuel pellets prepared in Example 3 of the present invention;

[0035] Figure 5 shows a CT test image of the nuclear fuel pellets prepared in Example 3 of the present invention;

[0036] Figure 6 shows the morphology of the nuclear fuel pellets prepared in Comparative Example 1 of the present invention;

[0037] Figure 7 Shows the CT test image of the nuclear fuel pellets prepared in Comparative Example 1 of the present invention;

[0038] Figure 8 A schematic diagram showing the shedding of the beryllium oxide layer of the nuclear fuel-coated particles prepared in Comparative Example 2 of the present invention after drying. DETAILED DESCRIPTION

[0039] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0040] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. Furthermore, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0041] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0042] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meaning commonly understood by those skilled in the art to which the present invention belongs.

[0043] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention, but not excluding other contents.

[0044] As used herein, the terms "optionally," "optional," or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0045] According to an embodiment of the present invention, a first aspect of the present invention provides a nuclear fuel-coated particle based on beryllium oxide, wherein the nuclear fuel-coated particle comprises a nuclear fuel particle and a beryllium oxide layer located on the periphery of the nuclear fuel particle;

[0046] The nuclear fuel particle comprises a fuel core, a loose pyrolytic carbon layer, an inner dense pyrolytic carbon layer and a carbide layer which are arranged in sequence from the inside to the outside.

[0047] The nuclear fuel-coated particles provided by the present invention solve the problem of uneven mixing of nuclear fuel particles and beryllium oxide powder materials due to the large density difference by coating beryllium oxide on the surface of the nuclear fuel particles, significantly improve the distribution uniformity of the nuclear fuel particles in the beryllium oxide matrix material, and effectively avoid serious problems such as particle breakage and even failure caused by direct contact of nuclear fuel particles under high pressure during the pressing and molding process, thereby greatly improving the safety of the nuclear fuel particles.

[0048] According to a specific embodiment of the present invention, the diameter of the nuclear fuel particles is 300 μm-1000 μm. As some specific examples, the diameter of the nuclear fuel particles can be 300 μm, 500 μm, 700 μm, 800 μm, 1000 μm, etc.

[0049] According to a specific embodiment of the present invention, the thickness of the beryllium oxide layer is 100 μm-500 μm. As some specific examples, the thickness of the beryllium oxide layer may be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc.

[0050] According to a specific embodiment of the present invention, the diameter of the fuel core is 100 μm-900 μm. As some specific examples, the diameter of the fuel core can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, etc. Specifically, the maximum loading amount of the nuclear fuel coating particles (i.e., the volume proportion of the fuel core in the nuclear fuel coating particles) is not less than 30%.

[0051] According to a specific embodiment of the present invention, the thickness of the loose pyrolytic carbon layer is 10μm-100μm. As some specific examples, the thickness of the loose pyrolytic carbon layer may be 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, etc.

[0052] According to a specific embodiment of the present invention, the thickness of the inner dense pyrolytic carbon layer is 3μm-50μm. As some specific examples, the thickness of the inner dense pyrolytic carbon layer can be 3μm, 10μm, 20μm, 30μm, 40μm, 50μm, etc.

[0053] According to a specific embodiment of the present invention, the thickness of the carbide layer is 15 μm-50 μm. As some specific examples, the thickness of the carbide layer may be 15 μm, 20 μm, 30 μm, 40 μm, 50 μm, etc.

[0054] According to a specific embodiment of the present invention, the material of the fuel core is not particularly limited. As some specific examples, the material of the fuel core includes but is not limited to at least one of zirconium carbide, tungsten carbide, uranium dioxide, uranium carbide, and uranium nitride.

[0055] According to a specific embodiment of the present invention, the material of the carbide layer is not particularly limited. As some specific examples, the material of the carbide layer includes but is not limited to at least one of silicon carbide, zirconium carbide, and niobium carbide.

[0056] According to a specific embodiment of the present invention, the beryllium oxide layer includes beryllium oxide and additives.

[0057] According to a specific embodiment of the present invention, the content of the additive in the beryllium oxide layer is 0.5wt%-5wt%. As some specific examples, the content of the additive in the beryllium oxide layer can be 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, etc.

[0058] According to a specific embodiment of the present invention, the type of the additive is not particularly limited. As some specific examples, the additive includes but is not limited to at least one of silicon dioxide, magnesium oxide, and aluminum oxide.

[0059] According to an embodiment of the present invention, a second aspect of the present invention provides a method for preparing the nuclear fuel-coated particles according to the first aspect, the preparation method comprising the following steps:

[0060] mixing beryllium oxide and additives, and granulating to obtain beryllium oxide powder;

[0061] The nuclear fuel particles are placed in a dressing device, and the beryllium oxide powder and ethanol aqueous solution are added into the dressing device to obtain the nuclear fuel dressing particles.

[0062] The nuclear fuel-coated particles can be prepared by the preparation method provided by the present invention. The nuclear fuel-coated particles can be directly used to prepare beryllium oxide-based dispersed fuel pellets and have high uniformity and safety.

[0063] According to a specific embodiment of the present invention, the volume ratio of ethanol to water in the ethanol-water solution is 1:3-3:1. As some specific examples, the volume ratio of ethanol to water in the ethanol-water solution can be 1:3, 2:3, 1:1, 3:2, 3:1, etc. Specifically, the nuclear fuel-coated particles can only be produced by adding a specific volume ratio of ethanol-water to the coating device. If ethanol or water alone is used, the beryllium oxide layer will fall off the surface of the nuclear fuel particles after drying.

[0064] According to a specific embodiment of the present invention, the preparation method further comprises: placing nuclear fuel particles in a dressing device, adding the beryllium oxide powder and ethanol aqueous solution into the dressing device, and drying to obtain the nuclear fuel dressing particles.

[0065] According to a specific embodiment of the present invention, the rotation speed of the dressing device is 150 rpm-250 rpm. As some specific examples, the rotation speed of the dressing device may be 150 rpm, 200 rpm, 250 rpm, etc.

[0066] According to a specific embodiment of the present invention, the drying temperature is 105°C-120°C. As some specific examples, the drying temperature may be 105°C, 110°C, 115°C, 120°C, etc.

[0067] According to a specific embodiment of the present invention, the drying time is 2 hours to 4 hours. As some specific examples, the drying time can be 2 hours, 3 hours, 4 hours, etc.

[0068] According to a specific embodiment of the present invention, the type of the dressing device is not particularly limited, for example, a coating machine can be used.

[0069] Below, the scheme of the present invention will be explained in conjunction with embodiment.It will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.In the embodiment, if specific technology or conditions are not indicated, the technology or conditions described in the literature in this area or the product instructions are used.The reagents or instruments used are not indicated by the manufacturer, and are all conventional products that can be obtained by commercial purchase.

[0070] Example 1

[0071] This embodiment provides a nuclear fuel-coated particle and a preparation method thereof, the preparation method comprising the following steps:

[0072] Weigh 39.019 g of nuclear fuel particles, wherein the fuel core is made of tungsten carbide, has a diameter of 440 μm, a loose pyrolytic carbon layer is 17 μm thick, an inner dense pyrolytic carbon layer is 3 μm thick, and the carbide layer is made of silicon carbide, with a thickness of 20 μm.

[0073] Weigh 35.464g of beryllium oxide powder (bulk density 0.80g / cm 3 , the material of the additive is silicon dioxide, and the content of the additive is 3.85wt%);

[0074] The nuclear fuel particles were placed in a coating machine, and the coating machine was started with the speed set to 200 rpm. After the speed of the coating machine stabilized, the beryllium oxide powder was added to the coating machine, and a mixture of anhydrous ethanol and deionized water (prepared by mixing 200 mL of anhydrous ethanol and 200 mL of deionized water) was sprayed into the coating machine until all the beryllium oxide powder was added to the coating machine. The total coating time was about 25 minutes.

[0075] The wet particles were placed in a culture dish and dried in an oven at 120°C for 2 hours to obtain the nuclear fuel coated particles (morphology as shown in FIG. Figure 1 The nuclear fuel pellets were hot pressed and sintered using a graphite die with an inner diameter of 23 mm to obtain nuclear fuel pellets with a loading of 20% (morphology as shown). Figure 2 The diameter of the nuclear fuel pellet is 22.98 mm, the length is 39.70 mm, and the mass is 72.079 g. The mass of the nuclear fuel pellet is reduced compared to the nuclear fuel dressing particle, mainly because some additives are volatilized and discharged during the sintering process.

[0076] Example 2

[0077] The nuclear fuel particles and beryllium oxide powder used in this embodiment are the same as those in Example 1, with the only difference being that the mass of the nuclear fuel particles is replaced from 39.019 g to 39.830 g, and the mass of the beryllium oxide powder is replaced from 35.464 g to 18.043 g.

[0078] The nuclear fuel particles were placed in a coating machine, and the coating machine was started with the speed set to 150 rpm. After the speed of the coating machine stabilized, the beryllium oxide powder was added to the coating machine, and a mixture of anhydrous ethanol and deionized water (prepared by mixing 150 ml of anhydrous ethanol and 300 ml of deionized water, respectively) was sprayed into the coating machine until all the beryllium oxide powder was added to the coating machine. The total coating time was about 20 minutes.

[0079] The nuclear fuel-coated particles were dried using the same method as in Example 1. The mass of the nuclear fuel-coated particles obtained was 56.639 g.

[0080] The nuclear fuel coating particles prepared in this embodiment were hot pressed and sintered in the same manner as in Example 1, using a graphite mold with an inner diameter of 18 mm to obtain nuclear fuel pellets with a loading amount of 30% (morphology as shown in FIG. Figure 3As shown), its diameter is 18.02mm, length is 49.52mm, and mass is 55.874g.

[0081] Example 3

[0082] The nuclear fuel particles and beryllium oxide powder used in this embodiment are the same as those in Example 1, with the only difference being that the mass of the nuclear fuel particles is replaced from 39.019 g to 19.510 g, and the mass of the beryllium oxide powder is replaced from 35.464 g to 42.032 g.

[0083] The nuclear fuel particles were placed in a coating machine, and the coating machine was started with the speed set to 250 rpm. After the speed of the coating machine stabilized, the beryllium oxide powder was added to the coating machine, and a mixture of anhydrous ethanol and deionized water (300 ml of anhydrous ethanol and 150 ml of deionized water, respectively) was sprayed into the coating machine until all the beryllium oxide powder was added to the coating machine. The total coating time was about 30 minutes.

[0084] The nuclear fuel-coated particles were dried using the same method as in Example 1. The mass of the nuclear fuel-coated particles obtained was 59.046 g.

[0085] The nuclear fuel coating particles prepared in this example were hot pressed and sintered in the same manner as in Example 1, using a graphite mold with an inner diameter of 23 mm to obtain nuclear fuel pellets with a loading amount of 10% (morphology as shown in FIG. Figure 4 The diameter of the nuclear fuel pellet is 22.98 mm, the length is 36.74 mm, and the mass is 57.367 g. The electronic computed tomography (CT) test results of the nuclear fuel pellet are as follows: Figure 5 As shown in the figure, it can be seen that the distribution of nuclear fuel particles is relatively uniform, and there is basically no contact between particles.

[0086] Comparative Example 1

[0087] This comparative example provides a nuclear fuel and a preparation method thereof, wherein the preparation method comprises the following steps:

[0088] Weigh 19.510 g of nuclear fuel particles (the material and thickness of each layer are the same as in Example 1) and 39.536 g of beryllium oxide powder (the material and content of the additive are the same as in Example 1), and directly mix the two to obtain nuclear fuel with a mass of 59.046 g, which is consistent with the mass of the nuclear fuel-coated particles in Example 3.

[0089] The nuclear fuel prepared in this comparative example was hot pressed and sintered in the same manner as in Example 1, using a graphite mold with an inner diameter of 23 mm to obtain nuclear fuel pellets with a loading amount of 10% (morphology as shown in FIG. Figure 6The CT test results of the nuclear fuel pellets are shown in Figure 2. Figure 7 As shown in the figure, it can be seen that the distribution of nuclear fuel particles is very uneven, and it is common for particles to contact each other, which leads to poor safety.

[0090] Comparative Example 2

[0091] The only difference between this comparative example and Example 1 is that "spraying a mixture of anhydrous ethanol and deionized water into the coating machine" is replaced by "spraying anhydrous ethanol into the coating machine".

[0092] The results showed that beryllium oxide powder could be evenly covered on the surface of nuclear fuel particles during the dressing process, but when all the wet particles were dried, it was found that the beryllium oxide layer on the surface of all nuclear fuel particles fell off, such as Figure 8 shown.

[0093] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0094] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A nuclear fuel-coated particle based on beryllium oxide, characterized in that: The nuclear fuel-coated particle comprises a nuclear fuel particle and a beryllium oxide layer located on the periphery of the nuclear fuel particle; The nuclear fuel particle comprises a fuel core, a loose pyrolytic carbon layer, an inner dense pyrolytic carbon layer and a carbide layer which are arranged in sequence from the inside to the outside.

2. The nuclear fuel-coated particle according to claim 1, characterized in that: The diameter of the nuclear fuel particles is 300 μm-1000 μm; Optionally, the beryllium oxide layer has a thickness of 100 μm to 500 μm.

3. The nuclear fuel-coated particle according to claim 1, characterized in that: The diameter of the fuel core is 100 μm-900 μm; Optionally, the thickness of the loose pyrolytic carbon layer is 10 μm-100 μm; Optionally, the thickness of the inner dense pyrolytic carbon layer is 3 μm-50 μm; Optionally, the carbide layer has a thickness of 15 μm to 50 μm.

4. The nuclear fuel-coated particle according to claim 1, characterized in that: The material of the fuel core includes at least one of zirconium carbide, tungsten carbide, uranium dioxide, uranium carbide, and uranium nitride.

5. The nuclear fuel-coated particle according to claim 1, characterized in that: The material of the carbide layer includes at least one of silicon carbide, zirconium carbide, and niobium carbide.

6. The nuclear fuel-coated particle according to claim 1, characterized in that: The beryllium oxide layer includes beryllium oxide and additives; Optionally, the content of the additive in the beryllium oxide layer is 0.5 wt%-5 wt%.

7. The nuclear fuel-coated particle according to claim 6, characterized in that: The additive includes at least one of silicon dioxide, magnesium oxide, and aluminum oxide.

8. A method for preparing the nuclear fuel-coated particles according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: mixing beryllium oxide and additives, and granulating to obtain beryllium oxide powder; The nuclear fuel particles are placed in a dressing device, and the beryllium oxide powder and ethanol aqueous solution are added into the dressing device to obtain the nuclear fuel dressing particles.

9. The preparation method according to claim 8, characterized in that The volume ratio of ethanol to water in the ethanol aqueous solution is 1:3-3:

1.

10. The preparation method according to claim 8, characterized in that The preparation method further comprises: placing nuclear fuel particles in a dressing device, adding the beryllium oxide powder and ethanol aqueous solution into the dressing device, and drying to obtain the nuclear fuel dressing particles; Optionally, the speed of the dressing device is 150 rpm-250 rpm; Optionally, the drying temperature is 105°C-120°C; Optionally, the drying time is 2h-4h.

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