TRISO fuel particle

Abstract

The invention provides a TRISO fuel particle which comprises a TRISO fuel particle body and a base body, the TRISO fuel particle body is embedded in the base body, the TRISO fuel particle body is coated with a loose pyrolytic carbon layer, and the density of the loose layer is 45-55%; the integrity of the ceramic packaging particles in a full-ceramic nuclear fuel application scene is improved, and the method for manufacturing the TRISO fuel particles only has few requirements for an existing manufacturing process, can be carried out on the basis of an existing process route and has universality.

Description

Technical Field

[0001] This application belongs to the field of ceramic encapsulated particle applications. More specifically, it relates to a TRISO fuel particle. Background Art

[0002] Ceramic encapsulated particles use ceramic materials as claddings to encapsulate substances in spherical microparticles. Taking TRISO (fully known as Tristructural Isotropic) fuel particles as an example, its full name is three-layer isotropic coated fuel particles, which are small-sized (about 1 mm in diameter) fuel particles obtained by using nuclear fuel (UN or UCO) as the material to be coated and coating it layer by layer with carbon coatings and silicon carbide coatings. This coating technology provides certain mechanical strength and material retention for the particles. Ceramic encapsulated particles can use a variety of ceramic materials as claddings, not limited to silicon carbide.

[0003] The main technical difficulty faced by ceramic encapsulated particles represented by TRISO particles in all-ceramic nuclear fuels is how to ensure the integrity of the particles. In all-ceramic fuels, ceramic encapsulated particles are dispersed in all-ceramic nuclear fuels with ceramic as the matrix material. They are wrapped by the ceramic matrix and fixed through direct contact between the cladding and the ceramic matrix. In addition, ceramic encapsulated particles may come into contact with each other to form aggregates of multiple particles. Due to the strong mechanical interlocking effect brought about by the close contact between ceramic encapsulated particles and the close contact between ceramic encapsulated particles and the ceramic matrix material, when cracks appear in the ceramic matrix, the claddings of ceramic encapsulated particles will crack accordingly, and the cracks will conduct along the claddings, ultimately leading to the complete rupture of the claddings and the leakage of the contained substances. Summary of the Invention

[0004] To achieve the above object, the technical solution adopted in this application is: to provide a TRISO fuel particle, including a TRISO fuel particle body and a matrix. The TRISO fuel particle body is embedded in the matrix, and a loose layer is coated on the TRISO fuel particle body, and the density of the loose layer is 45-55%.

[0005] As a possible design, the density of the loose layer is 50%.

[0006] As a possible design, the loose layer is made of pyrolytic carbon.

[0007] As a possible design, the thickness of the loose layer is 40-60 μm.

[0008] As a possible design, the thickness of the loose layer is 50 μm.

[0009] As a possible design, the TRISO fuel particle body includes a TRISO fuel core, a loose pyrolytic carbon layer, an inner dense pyrolytic carbon layer, a silicon carbide layer, and an outer dense pyrolytic carbon layer, which are arranged in sequence from the inside to the outside.

[0010] As a possible design, the matrix is made of ceramics.

[0011] As a possible design, the density of the loose pyrolytic carbon layer is 45-55%.

[0012] As a possible design, the density of the loose pyrolytic carbon layer is 50%.

[0013] The beneficial effects of the TRISO fuel particles provided in this application are as follows: The present invention solves the problem of cladding cracking that occurs when ceramic encapsulated particles are applied in all-ceramic nuclear fuels, improves the integrity of ceramic encapsulated particles in the application scenario of all-ceramic nuclear fuels, and the method for manufacturing the TRISO fuel particles only has relatively few requirements for the existing manufacturing process and can be based on the existing process route, having universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is a schematic diagram of the layered structure of the existing TRISO fuel particles provided in the embodiments of the present application;

[0016] Figure 2 It is a schematic diagram of the structure of the existing TRISO fuel particles provided in the embodiments of the present application;

[0017] Figure 3 It is a schematic diagram of the layered structure of the improved TRISO fuel particles provided in the embodiments of the present application.

[0018] Among them, the reference numerals in the drawings are as follows:

[0019] 1 - TRISO fuel core; 2 - loose pyrolytic carbon layer, 3 - inner dense pyrolytic carbon layer, 4 - silicon carbide layer, 5 - outer dense pyrolytic carbon layer, 6 - matrix, 7 - TRISO fuel particle body, 8 - loose layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the following further details this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0021] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0022] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this application.

[0023] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality" means two or more, unless otherwise specifically defined.

[0024] The main reason for the cladding cracking of the above-mentioned TRISO particles is the strong mechanical interlocking effect generated by the close contact between the claddings and between the cladding and the ceramic matrix, which causes the cracks generated in the ceramic matrix to conduct through the closely fitting parts.

[0025] To solve the above problems, an improved TRISO fuel particle is provided. Please refer to Figures 1-3 , and now the TRISO fuel particle provided by the embodiment of this application is described. The TRISO fuel particle includes a TRISO fuel particle body 7 and a matrix 6. The TRISO fuel particle body 7 is embedded in the matrix 6. The matrix 6 is coated with a loose layer 8. The density of the loose layer 8 is 45-55%, and the loose layer 8 is made of pyrolytic carbon.

[0026] As shown in Figure 1 and Figure 2As shown, the TRISO fuel particle body 7 includes a TRISO fuel core 1, a loose pyrolytic carbon layer 2, an inner dense pyrolytic carbon layer 3, a silicon carbide layer 4, and an outer dense pyrolytic carbon layer 5, which are arranged in sequence from the inside to the outside. The TRISO fuel core 1 occupies most of the volume of the TRISO particle to provide nuclear fuel to the maximum extent. The density of the loose pyrolytic carbon layer 2 is about 50%, preferably 50%, and is used to accommodate nuclear fuel. The inner dense pyrolytic carbon layer 3 and the outer dense pyrolytic carbon layer 5 respectively provide inward and outward buffering for the silicon carbide layer 4.

[0027] In the present invention, the main components, effects, and structures of the TRISO fuel core 1, the loose pyrolytic carbon layer 2, the inner dense pyrolytic carbon layer 3, the silicon carbide layer 4, and the outer dense pyrolytic carbon layer 5 are all prior arts, so they will not be elaborated in detail here.

[0028] It should be noted that the materials used to make the loose layer 8 and the loose pyrolytic carbon layer 2 in the present invention are the same.

[0029] As Figure 3 shown, the loose layer 8 can play a buffering role when the micro-particles contact each other and when the micro-particles contact the ceramic matrix material. The density of the loose layer 8 is about 50%, ensuring that the particles are not closely attached when they contact each other and when the particles contact the ceramic matrix. When a crack extends through the ceramic matrix to this layer, its large number of loose pores can accommodate the extension of the crack or deflect it, so that the crack does not conduct deeper into the particle.

[0030] The production of the TRISO fuel particles provided by the present invention only requires a small change to the existing process, that is, adding a process of adhering the loose layer on the basis of the existing process, and this process is simple and easy to implement.

[0031] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A TRISO fuel particle, comprising a TRISO fuel particle body and a matrix, the TRISO fuel particle body being embedded in the matrix, characterized in that: The TRISO fuel particle body is coated with a loose layer, and the density of the loose layer is 45-55%.

2. The TRISO fuel particle according to claim 1, wherein: The density of the loose layer is 50%.

3. The TRISO fuel particle according to claim 1, characterized in that: The loose layer is made of pyrolytic carbon.

4. The TRISO fuel particle according to claim 1, characterized in that: The thickness of the loose layer is 40-60 um.

5. The TRISO fuel particle according to claim 4, characterized in that: The thickness of the loose layer is 50 um.

6. The TRISO fuel particle according to claim 1, characterized in that: The TRISO fuel particle body includes a TRISO fuel core, a loose pyrolytic carbon layer, an inner dense pyrolytic carbon layer, a silicon carbide layer, and an outer dense pyrolytic carbon layer, which are arranged in sequence from the inside to the outside.

7. The TRISO fuel particle according to claim 6, characterized in that: The matrix is made of ceramics.

8. The TRISO fuel particle according to claim 6, wherein: The density of the loose pyrolytic carbon layer is 45-55%.

9. The TRISO fuel particle according to claim 8, wherein: The density of the loose pyrolytic carbon layer is 50%.

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