Spacer grid suitable for fuel rod and fuel assembly

Abstract

The embodiment of the invention relates to the technical field of nuclear fuel, in particular to a positioning grillwork suitable for a fuel rod and a fuel assembly, and the positioning grillwork comprises a frame assembly which is arranged to form a plurality of accommodating spaces; each of the plurality of clamping assemblies is arranged to have two ends connected with the frame assembly, to be elastically deformable, and to have an adjustable distance between the two ends, the clamping assemblies have no force effect on the fuel rod when the fuel rod is inserted into the accommodating space, and after the fuel rod is inserted into the accommodating space, the fuel rod is inserted into the accommodating space by adjusting the distance. And the clamping assembly can exert a powerful effect on the fuel rod. By adjusting the distance between the two ends of the clamping assembly, when the fuel rod is inserted into the containing space, the surface of the fuel rod is prevented from being scratched, the probability that the fuel rod is abraded is reduced, and therefore the situation that the surface of the fuel rod falls off, and the fuel rod is abraded by scraps is affected is avoided, the running safety of the fuel assembly is guaranteed, and the service life of the fuel assembly is prolonged. And after the fuel rod is inserted into the accommodating space, the fuel rod is positioned stably.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of nuclear fuel technology, and in particular to a spacer grid and a fuel assembly suitable for fuel rods. Background Art

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

[0003] Reactor fuel assemblies are important components in nuclear reactors, which are mainly composed of fuel rods, spacer grids and other structures. In the reactor of a nuclear power plant, fuel assemblies are loaded into the core to generate heat energy through nuclear fission, which is then converted into electrical energy.

[0004] Spacer grids are structural components used to fix fuel rods. With the continuous update of reactor fuel assembly design, the requirements for spacer grids are also changing. Spacer grids include support frames, which are in direct contact with fuel rods and are key components for determining the position of fuel rods. However, current spacer grids have many deficiencies in positioning fuel rods. Summary of the invention

[0005] 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.

[0006] In a first aspect, an embodiment of the present application provides a positioning grid suitable for fuel rods, comprising: a frame assembly, the frame assembly is configured to form a plurality of accommodating spaces and is configured to be inserted by fuel rods; a plurality of clamping assemblies, each of the plurality of clamping assemblies is configured so that its two ends can be movably fixedly connected to the frame assembly, configured to be elastically deformable, and configured so that the distance between its two ends can be adjusted, when the fuel rod is inserted into the accommodating space, the clamping assembly has no force on the fuel rod, and after the fuel rod is inserted into the accommodating space, the clamping assembly can exert a force on the fuel rod by adjusting the distance to enable the fuel rod to be positioned.

[0007] The embodiment of the present application configures the clamping assembly to be elastically deformable and the distance between its two ends to be adjustable, which is beneficial for adjusting the degree of elastic deformation of the clamping assembly by adjusting the distance between the two ends of the clamping assembly, thereby achieving the purpose of adjusting the force applied by the clamping assembly to the fuel rod, so that the clamping assembly has no force on the fuel rod when the fuel rod is inserted into the accommodating space, avoiding surface scratches on the fuel rod, reducing the probability of wear of the fuel rod, thereby avoiding the impact of the shedding of the fuel rod surface on the abrasion of the fuel rod by debris, ensuring the safety of the operation of the fuel assembly, and after the fuel rod is inserted into the accommodating space, the clamping assembly can have a strong effect on the fuel rod, thereby achieving relatively stable positioning of the fuel rod and better positioning effect.

[0008] In a second aspect, an embodiment of the present application further provides a fuel assembly, which includes: a plurality of fuel rods and a spacer grid according to an embodiment of the present application, wherein the fuel rods are arranged in the spacer grid.

[0009] These and other advantages of the present application will become more apparent through the following detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 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.

[0011] Figure 1 is a schematic structural diagram of a spacer grid applicable to fuel rods according to an embodiment of the present application;

[0012] Figure 2 yes Figure 1 A top view of the spacer grid is shown;

[0013] Figure 3 is a schematic structural diagram of a clamping assembly in a first state according to an embodiment of the present application;

[0014] Figure 4 yes Figure 3 a cross-sectional view of the clamp assembly shown;

[0015] Figure 5 is a schematic structural diagram of a clamping assembly in a second state according to an embodiment of the present application;

[0016] Figure 6 It is a schematic structural diagram of the clamping assembly in the third state according to an embodiment of the present application.

[0017] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

[0018] Description of reference numerals:

[0019] 10. Positioning grid;

[0020] 11. frame assembly; 111. accommodating space; 112. first frame member; 1121. matching portion; 113. second frame member;

[0021] 12. Clamping assembly; 121. Elastic member; 122. Matching member; 1221. Fixing portion; 1222. Connecting portion. DETAILED DESCRIPTION

[0022] 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.

[0023] 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.

[0024] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should have the common meanings understood by persons with ordinary skills in the field to which this application belongs.

[0025] In the description of the embodiments of the present application, “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] In the related art, the commonly used positioning grids include strip-type positioning grids, grid-element positioning grids, and wire-wound positioning structures, etc. These positioning grids have many shortcomings. For example, for the grid-element positioning grid, which is composed of a circumference plate and a plurality of grid-element tubes, when clamping the fuel rod, the position of the fuel rod is mainly maintained by the friction force limited by the elastic interference of the grid element to the fuel rod and the grid element to the guide tube. This method of clamping the fuel rod cannot adjust the size of the clamping force. When the fuel rod is inserted into the grid element, due to the large friction force, the surface of the fuel rod is easily scratched severely, resulting in the adverse effect of the fallen debris on the abrasion of the fuel rod during the operation of the fuel assembly.

[0027] In view of the above technical problems, the embodiments of the present application provide a spacer grid suitable for fuel rods. Figure 1 is a schematic structural diagram of a spacer grid applicable to fuel rods according to an embodiment of the present application, Figure 2 yes Figure 1 A top view of the spacer grid is shown, as Figure 1 and Figure 2 As shown, the spacer grid 10 includes a frame assembly 11 and a plurality of clamping assemblies 12 .

[0028] The frame assembly 11 is configured to form a plurality of accommodation spaces 111 and is configured to be inserted with fuel rods.

[0029] A plurality of clamping assemblies 12 are provided, each of the plurality of clamping assemblies 12 is configured so that its two ends can be movably fixedly connected to the frame assembly 11, is configured so that it can be elastically deformed, and is configured so that the distance between its two ends can be adjusted. When the fuel rod is inserted into the accommodating space 111, the clamping assemblies 12 have no force on the fuel rod. After the fuel rod is inserted into the accommodating space 111, the clamping assemblies 12 can exert a strong force on the fuel rod by adjusting the distance, so that the fuel rod can be positioned.

[0030] The embodiment of the present application sets the clamping assembly 12 to be elastically deformable and sets the distance between its two ends to be adjustable, which is beneficial to adjusting the degree of elastic deformation of the clamping assembly 12 by adjusting the distance between the two ends of the clamping assembly 12, thereby achieving the purpose of adjusting the force applied by the clamping assembly 12 to the fuel rod, so that the clamping assembly 12 has no force on the fuel rod when the fuel rod is inserted into the accommodating space 111, thereby avoiding scratches on the surface of the fuel rod and reducing the probability of wear of the fuel rod, thereby avoiding the impact of the shedding of the fuel rod surface on the abrasion of the fuel rod by debris, ensuring the safety of the operation of the fuel assembly, and after the fuel rod is inserted into the accommodating space 111, the clamping assembly 12 can have a strong effect on the fuel rod, so as to achieve the positioning of the fuel rod in a relatively stable manner and with a good positioning effect.

[0031] In some embodiments, for each clamping assembly 12, its two ends are movably fixedly connected to the frame assembly 11, which can be understood as: either end is detachable from the frame assembly 11, and when connected to the frame assembly 11, its final connection state is a fixed connection.

[0032] In some embodiments, the clamping assembly 12 is configured with one end fixed on the frame assembly 11 and the other end capable of adjusting position on the frame assembly 11, so as to adjust the distance between the two ends of the clamping assembly 12 and thereby adjust the degree of its elastic deformation, which is relatively easy to operate.

[0033] In some embodiments, one end of the clamping assembly 12 is welded to the frame assembly 11 so as to be fixed to the frame assembly 11 .

[0034] In some embodiments, the clamping assembly 12 is configured so that both ends thereof can be adjusted on the frame assembly 11, so as to adjust the distance between the two ends of the clamping assembly 12 and thereby adjust the degree of its elastic deformation, which is relatively easy to operate.

[0035] In some embodiments, Figure 3 is a schematic structural diagram of a clamping assembly in a first state according to an embodiment of the present application, Figure 4 yes Figure 3 A cross-sectional view of the clamping assembly shown in FIG. Figure 3 and Figure 4 As shown, the clamping assembly 12 includes an elastic member 121 and a matching member 122. Both ends of the elastic member 121 are fixedly connected to the matching member 122 respectively. A plurality of mating portions 1121 are formed in the frame assembly 11, and the mating piece 122 is configured to be mated with the mating portion 1121, and is configured to be able to move from one mating portion 1121 to another mating portion 1121 under the action of an external force. When the mating piece 122 is in the mating portion 1121, the mating portion 1121 is fixedly connected to the mating piece 122, so that the mating piece 122 is fixedly connected to the frame assembly 11; when the mating piece 122 moves from one mating portion 1121 to another mating portion 1121, the distance between the two mating pieces 122 will change, so that the elastic piece 121 changes from a stretched state to a bent state, so that when the fuel rod is inserted into the accommodating space 111, the elastic piece 121 has no force on the fuel rod. After the fuel rod is inserted into the accommodating space 111, the elastic piece 121 can exert a force on the fuel rod by adjusting the distance, so that the fuel rod can be positioned.

[0036] In the embodiment of the present application, a plurality of mating parts 1121 are arranged on the frame assembly 11, and the mating parts 122 are arranged to be able to move from one mating part 1121 to another mating part 1121 under the action of an external force, so as to change the distance between the two mating parts 122, thereby changing the degree of elastic deformation of the elastic part 121, so that the elastic part 121 is changed from a stretched state to a bent state. The operation is relatively simple, and the force applied to the fuel rod by the elastic part 121 in the bent state ensures that the fuel rod is firmly positioned.

[0037] Figure 5 is a schematic structural diagram of a clamping assembly in a second state according to an embodiment of the present application, Figure 6 is a schematic structural diagram of the clamping assembly according to an embodiment of the present application when it is in the third state, such as Figure 3 , Figure 5 as well as Figure 6 As shown, when the clamping assembly 12 is in the first state, the two fitting pieces 122 cooperate with the two fitting parts 1121 that are farther apart, and the elastic piece 121 is in a stretched state, and the fitting piece 122 is fixedly connected to the fitting part 1121. In the process of inserting the fuel rod into the accommodating space 111, the elastic piece 121 has no force on the fuel rod, that is, the elastic piece 121 will not scratch the surface of the fuel rod; when the clamping assembly 12 is in the second state, the two fitting pieces 122 are separated from the fitting part 1121, and the clamping assembly 12 and the frame assembly 11 are in a disassembled state; when the clamping assembly 12 is in the third state, the two fitting pieces 122 cooperate with the two fitting parts 1121 that are closer to each other, and the fuel rod has been inserted into the accommodating space 111, the elastic piece 121 is in a bent state, and the fitting piece 122 is fixedly connected to the fitting part 1121. The elastic piece 121 can exert a supporting force on the fuel rod, so that the fuel rod can be positioned.

[0038] In such an embodiment, Figure 3 As shown, the two matching portions 1121 that are closer to each other are two matching portions 1121 other than the two matching portions 1121 that are farthest from each other among the multiple matching portions 1121 .

[0039] In such an embodiment, the first state is an extended state and the third state is a bent state.

[0040] In some embodiments, after the elastic member 121 changes from the stretched state to the bent state, the elastic member 121 protrudes toward the center of the accommodating space 111 .

[0041] In some embodiments, the elastic member 121 is a spring structure, and the material of the elastic member 121 is a deformable memory alloy.

[0042] In such an embodiment, the elastic member 121 is a double-sided triple-bend spring structure.

[0043] In some embodiments, after the fuel rod is inserted into the accommodating space 111 and the fitting 122 is moved from one fitting portion 1121 to another fitting portion 1121, that is, after the elastic member 121 is changed from a stretched state to a bent state, a heating furnace is used to perform heat treatment on the position of the entire spacer grid 10 to solidify the shape of the elastic member 121 and eliminate the stress generated during assembly.

[0044] In some embodiments, the clamping assembly 12 includes an elastic member 121 and a matching member 122 . One end of the elastic member 121 is fixedly connected to the matching member 122, and the other end of the elastic member 121 is fixedly connected to the frame assembly 11; a plurality of matching portions 1121 are formed on the frame assembly 11, and the matching member 122 is configured to match with the matching portion 1121, and is configured to be able to move from one matching portion 1121 to another matching portion 1121 under the action of an external force; when the matching member 122 is in the matching portion 1121, the matching portion 1121 is fixedly connected to the matching member 122, so that the matching member 122 is fixedly connected to the frame assembly 11; when the matching member 122 moves from one matching portion 1121 to another matching portion 1121, the distance between the two ends of the elastic member 121 will change, so that the elastic member 121 changes from a stretched state to a bent state, so that when the fuel rod is inserted into the accommodating space 111, the elastic member 121 has no force on the fuel rod, and after the fuel rod is inserted into the accommodating space 111, the elastic member 121 can have a strong effect on the fuel rod by adjusting the distance, so that the fuel rod can be positioned.

[0045] In the embodiment of the present application, a plurality of mating parts 1121 are arranged on the frame assembly 11, and the mating parts 122 in the clamping assembly 12 are arranged to be able to move from one mating part 1121 to another mating part 1121 under the action of an external force, so as to change the distance between the two mating parts 122, thereby changing the degree of elastic deformation of the elastic part 121, so that the elastic part 121 is changed from a stretched state to a bent state. The operation is relatively simple, and the force applied to the fuel rod by the elastic part 121 in the bent state ensures that the fuel rod is firmly positioned.

[0046] In some embodiments, the mating piece 122 forms a fixing portion 1221 and a connecting portion 1222, the fixing portion 1221 is formed at both ends of the connecting portion 1222, and the mating portion 1121 is formed into a shape that matches the fixing portion 1221 so that the fixing portion 1221 can be fixed to the mating portion 1121; wherein one end of the elastic piece 121 is fixedly connected to the connecting portion 1222.

[0047] In the embodiment of the present application, the elastic member 121 connected to the connecting portion 1222 can be fixed on the frame assembly 11 through the cooperation between the fixing portion 1221 of the matching member 122 and the matching portion 1121, thereby ensuring the stability of the connection between the elastic member 121 and the frame assembly 11.

[0048] In some embodiments, the mating piece 122 is configured to form an "I" shape, the mating portion 1121 is configured to form an "I" shaped hole, and the fixing portion 1221 cooperates with the mating portion 1121 to prevent the fixing portion 1221 from shaking, thereby further improving the stability of the connection between the elastic piece 121 and the frame assembly 11.

[0049] In some embodiments, the fixing portion 1221 is the “-” portion in the “I” structure, and the connecting portion 1222 is the “|” portion in the “I” structure.

[0050] In some embodiments, the “I”-shaped holes of the plurality of “I”-shaped holes respectively matched with the same fixing portion 1221 are arranged adjacent to each other to improve the convenience of moving the matching piece 122 from one matching portion 1121 to another matching portion 1121 .

[0051] In some embodiments, if one end of the elastic member 121 is fixedly connected to the mating member 122 and the other end is fixedly connected to the frame assembly 11, then the "I"-shaped holes among the multiple "I"-shaped holes respectively mating with the same fixing portion 1221 are arranged to have a predetermined spacing.

[0052] In some embodiments, the frame assembly 11 includes a first frame member 112 and a second frame member 113, and the multiple first frame members 112 are configured to cooperate with each other to form a plurality of accommodating spaces 111, the first frame member 112 is configured to be fixedly connected to the second frame member 113, and the second frame member 113 is arranged on the outside of the first frame member 112, wherein the multiple clamping assemblies 12 are configured to be fixedly connected to the multiple first frame members 112.

[0053] In the embodiment of the present application, a plurality of accommodating spaces 111 are formed by cooperation between the first frame member 112 and the second frame member 113, so that a plurality of fuel rods can be accommodated in the plurality of accommodating spaces 111, thereby flexibly adjusting the number of accommodated fuel rods and having a wide range of applications.

[0054] In some embodiments, the second frame member 113 is a polygonal strip structure, for example, a quadrilateral strip structure or a hexagonal strip structure, etc. The first frame member 112 is a combination structure of strips that cooperate with each other.

[0055] In such an embodiment, slots are provided on each strip in the first frame member 112 and the second frame member 113 , and a plurality of strips can be connected through the slots on the strips and welded after connection to form the frame assembly 11 .

[0056] exist Figure 1 and Figure 2 In the illustrated embodiment, the first frame member 112 and the second frame member 113 together form a square cell space (accommodating space 111 ).

[0057] In some embodiments, the frame assembly 11 includes a first frame member 112 and a second frame member 113, and the multiple first frame members 112 are configured to cooperate with each other to form a plurality of accommodating spaces 111, the first frame member 112 is configured to be fixedly connected to the second frame member 113, and the second frame member 113 is arranged on the outside of the first frame member 112, wherein the multiple clamping assemblies 12 are configured to be fixedly connected to the multiple first frame members 112.

[0058] In the embodiment of the present application, a plurality of accommodating spaces 111 are formed by cooperation between the first frame member 112 and the second frame member 113, so that a plurality of fuel rods can be accommodated in the plurality of accommodating spaces 111, thereby flexibly adjusting the number of accommodated fuel rods and having a wide range of applications.

[0059] In some embodiments, the mating portion 1121 is configured to be formed on the first frame member 112 so as to securely position the fuel rod in the accommodating space 111 .

[0060] In some embodiments, for any accommodating space 111 , a plurality of clamping assemblies 12 are fixedly connected to a corresponding portion of the first frame member 112 , and the inner walls of the accommodating space 111 where the plurality of clamping assemblies 12 are located are different.

[0061] The embodiment of the present application further provides a method for assembling fuel rods and a spacer grid 10 , and the assembly method includes steps S1 to S4 .

[0062] S1. Fix the two matching pieces 122 in the clamping assembly 12 to the two matching portions 1121 on the first frame member 112 which are farther apart, so that the elastic piece 121 is in the first state.

[0063] S2. Insert the fuel rod into the accommodating space 111 of the frame assembly 11.

[0064] S3. Apply a first external force to the clamping assembly 12 to separate the two mating members 122 of the clamping assembly 12 from the two mating portions 1121 on the first frame member 112 that are farther apart, thereby placing the elastic member 121 in the second state.

[0065] S4. Continue to apply a second external force to the clamping assembly 12, so that the two matching pieces 122 of the clamping assembly 12 are fixedly connected to the two matching parts 1121 on the first frame member 112 that are close to each other, so that the elastic piece 121 is in the third state, so that the elastic piece 121 can be used to clamp the fuel rod.

[0066] The method provided in the embodiment of the present application adjusts the force applied by the clamping assembly 12 to the fuel rod by adjusting the connection state between the matching piece 122 in the clamping assembly 12 and the different matching parts 1121 in the frame assembly 11, so that when the fuel rod is inserted into the accommodating space 111, the clamping assembly 12 has no force on the fuel rod, thereby avoiding surface scratches on the fuel rod and reducing the probability of wear of the fuel rod, thereby avoiding the impact of the shedding of the fuel rod surface on the abrasion of the fuel rod by debris, ensuring the safety of the operation of the fuel assembly, and after the fuel rod is inserted into the accommodating space 111, the clamping assembly 12 can have a strong effect on the fuel rod, so as to achieve the positioning of the fuel rod in a relatively stable manner and with a good positioning effect.

[0067] The embodiment of the present application further provides a fuel assembly, which includes: a plurality of fuel rods and a spacer grid 10 according to the embodiment of the present application, wherein the fuel rods are arranged in the spacer grid 10 .

[0068] The embodiment of the present application can avoid surface scratches on the fuel rods and reduce the probability of wear of the fuel rods by arranging the fuel rods in the positioning grid 10, thereby avoiding the influence of the abrasion of the fuel rods by the debris falling off the surface of the fuel rods, ensuring the safety of the operation of the fuel assembly and ensuring the stability of the positioning of the fuel rods.

[0069] 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.

[0070] The above description is only a specific implementation manner 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 spacer grid suitable for fuel rods, characterized in that: It includes: a frame assembly, the frame assembly being configured to form a plurality of accommodation spaces and being configured to be inserted by the fuel rods; A plurality of clamping assemblies, each of the plurality of clamping assemblies is configured so that its two ends can be movably fixedly connected to the frame assembly, is configured so that it can be elastically deformed, and is configured so that the distance between its two ends can be adjusted, when the fuel rod is inserted into the accommodating space, the clamping assembly has no force effect on the fuel rod, and after the fuel rod is inserted into the accommodating space, by adjusting the distance, the clamping assembly can have a strong effect on the fuel rod so that the fuel rod can be positioned.

2. The spacer grid according to claim 1, characterized in that: The clamping assembly is configured such that one end thereof is fixed to the frame assembly and the other end thereof can be adjusted in position on the frame assembly.

3. The spacer grid according to claim 1, characterized in that: The clamping assembly is configured so that both ends thereof can be adjusted in position on the frame assembly.

4. The spacer grid according to claim 1 or 3, characterized in that: The clamping assembly includes an elastic member and a matching member, and both ends of the elastic member are fixedly connected to the matching member respectively. A plurality of mating parts are formed in the frame assembly, the mating piece is configured to be mated with the mating parts, and is configured to be able to move from one mating part to another mating part under the action of an external force, and when the mating piece is in the mating part, the mating part is fixedly connected to the mating piece, so that the mating piece is fixedly connected to the frame assembly; When the fitting piece moves from one fitting part to another fitting part, the distance between the two fitting pieces will change, so that the elastic piece changes from a stretched state to a bent state, so that when the fuel rod is inserted into the accommodating space, the elastic piece has no force acting on the fuel rod. After the fuel rod is inserted into the accommodating space, by adjusting the distance, the elastic piece can exert a force on the fuel rod, so that the fuel rod can be positioned.

5. The spacer grid according to claim 2, characterized in that: The clamping assembly comprises an elastic member and a matching member, one end of the elastic member is fixedly connected to the matching member, and the other end of the elastic member is fixedly connected to the frame assembly; A plurality of mating parts are formed in the frame assembly, the mating piece is configured to be mated with the mating parts, and is configured to be able to move from one mating part to another mating part under the action of an external force, and when the mating piece is in the mating part, the mating part is fixedly connected to the mating piece, so that the mating piece is fixedly connected to the frame assembly; When the fitting piece moves from one fitting part to another fitting part, the distance between the two ends of the elastic piece will change, so that the elastic piece changes from a stretched state to a bent state, so that when the fuel rod is inserted into the accommodating space, the elastic piece has no force acting on the fuel rod. After the fuel rod is inserted into the accommodating space, by adjusting the distance, the elastic piece can exert a force on the fuel rod, so that the fuel rod can be positioned.

6. The spacer grid according to claim 4 or 5, characterized in that: The matching piece forms a fixing portion and a connecting portion, the fixing portion is formed at both ends of the connecting portion, and the matching portion is formed into a shape matching with the fixing portion so that the fixing portion can be fixed to the matching portion; Wherein, one end of the elastic member is fixedly connected to the connecting portion.

7. The spacer grid according to claim 6, characterized in that: The matching piece is configured to be formed into an "I" shape, the matching portion is configured to be formed into an "I"-shaped hole, and the fixing portion matches with the matching portion.

8. The spacer grid according to claim 7, characterized in that: The "I"-shaped holes of the plurality of said "I"-shaped holes are respectively arranged adjacent to the "I"-shaped holes matched with the same said fixing part.

9. The spacer grid according to claim 1, characterized in that: The frame assembly includes a first frame member and a second frame member, wherein a plurality of the first frame members are arranged to cooperate with each other to form a plurality of accommodation spaces. The first frame member is arranged to be fixedly connected to the second frame member, and the second frame member is arranged on the outside of the first frame member. Wherein, the plurality of clamping assemblies are configured to be fixedly connected to the plurality of the first frame members.

10. The spacer grid according to any one of claims 5 to 8, characterized in that: The frame assembly includes a first frame member and a second frame member, wherein a plurality of the first frame members are arranged to cooperate with each other to form a plurality of accommodation spaces. The first frame member is arranged to be fixedly connected to the second frame member, and the second frame member is arranged on the outside of the first frame member. Wherein, the plurality of clamping assemblies are configured to be fixedly connected to the plurality of the first frame members.

11. The spacer grid according to claim 10, characterized in that The mating portion is configured to be formed on the first frame member.

12. A fuel assembly, characterized in that: It includes: A plurality of fuel rods and a spacer grid as claimed in any one of claims 1 to 11, The fuel rods are arranged in the spacer grid.

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