WO2020173506A1

WO2020173506A1 - Fuel assembly and positioning grid

Info

Publication number: WO2020173506A1
Application number: PCT/CN2020/085410
Authority: WO
Inventors: 颜景文; 刘雨利; 刘贻潮; 李伟才; 庞铮铮; 张玉相
Original assignee: 广东核电合营有限公司; 中广核研究院有限公司; 中国广核集团有限公司; 中国广核电力股份有限公司
Priority date: 2019-02-27
Filing date: 2020-04-17
Publication date: 2020-09-03
Also published as: CN109920561B; CN109920561A

Abstract

A fuel assembly and a positioning grid, comprising several first strips (11) arranged in parallel at intervals and several second strips (12) arranged in parallel at intervals, the first strips (11) intersecting the second strips (12) to form a grid for fuel rods (2) to be inserted, the positioning grid (1) also comprising an elastic clamping mechanism (3), the elastic clamping mechanism (3) comprising clamping parts (33) located within the grid, the clamping parts (33) of the elastic clamping mechanism (3) being capable of switching between first positions and second positions in the lateral direction of the grid. When in the first positions, the clamping parts (33) of the elastic clamping mechanism (3) form channels, larger than the outer diameter of the fuel rods (2), within the grid, and when in the second positions, the clamping parts (33) of the elastic clamping mechanism (3) clamp the fuel rods (2) inserted into the grid. The clamping parts (33) move in the lateral direction to clamp the fuel rods (2), so as to avoid scratching as the fuel rods (2) are inserted into the grid, reduce the risk of abrasion between the fuel rods (2) and the clamping system, form stable surface contact between the fuel rods (2) and the clamping system, and increase the safety of the fuel assembly.

Description

Fuel assembly and positioning grid technical field

[0001] The present invention relates to the field of nuclear power, and more specifically, to a fuel assembly and a positioning grid.

Background technique

[0002] The existing fuel assembly positioning grid adopts a clamping system composed of a spring and a rigid convex structure to maintain a stable position of the fuel rod in the fuel assembly.

[0003] The existing spring is in contact with the fuel rod through the convex surface. The contact between the fuel rod and the rigid convex spring in this structure is line contact or even point contact. When the fuel rod vibrates, the fuel rod is in contact with the fuel rod. The contact area of spring or rigid convex is prone to abrasion.

[0004] The rigid-convex structure of the existing product scratches the fuel rod during the process of installing the fuel assembly into the fuel assembly grid, which will form significant scratches on the surface of the fuel rod, which is an important risk affecting the structural integrity of the fuel rod. Summary of the invention

technical problem

[0005] The technical problem to be solved by the present invention is to provide a fuel assembly and a positioning grid that clamp fuel rods by lateral movement.

The solution to the problem

Technical solutions

[0006] The technical solution adopted by the present invention to solve its technical problem is: construct a fuel assembly positioning grid, including a plurality of first strips arranged side by side at intervals and a plurality of second strips arranged side by side at intervals, the first The strip and the second strip cross each other to form a plurality of grids for fuel rods to pass through, and the positioning grid frame further includes an elastic clamping mechanism;

[0007] The elastic clamping mechanism includes a clamping portion located in each of the grids;

[0008] The clamping portion of the elastic clamping mechanism can be switched between the first and second positions in the transverse direction of the grid; [0009] when the clamping portion of the elastic clamping mechanism is in the first position , Forming a channel larger than the outer diameter of the fuel rod in the grid;

[0010] When the clamping portion of the elastic clamping mechanism is in the second position, it opposes the fuel rods inserted in the grid Form clamping.

[0011] Preferably, the elastic clamping mechanism includes a plurality of first clamping units, and each of the first clamping units and the second strip are arranged side by side, and each of the first strips is passed through in turn;

[0012] Each of the first clamping units respectively forms the clamping portion in a row of the grids distributed along the extending direction of the second strip, and the first strip is provided with a counter The first guiding structure for guiding the lateral movement of the first clamping unit.

[0013] Preferably, the first clamping unit includes two symmetrical first clamping bands to clamp the fuel rods from both sides.

[0014] Preferably, a portion of the first clamping belt of the first clamping unit located in the grid is provided with the clamping portion, the clamping portion is arc-shaped, and the first The openings of the clamping parts of the two first clamping bands of the clamping unit are opposite to each other.

[0015] Preferably, the first guide structure includes a plurality of groups of first guide grooves distributed along the length direction on each of the first strips and corresponding to each of the grid positions one by one, and each group of the first guide grooves The first guide groove includes two symmetrical first guide grooves;

[0016] The two first clamping belts of each first clamping unit respectively pass through the corresponding first guide grooves of each group of the first guide grooves;

[0017] The first guide groove includes an inclined first guide section, which moves the elastic clamping mechanism laterally while moving in the axial direction of the grid, so that the clamping portion is in the Switch between the first position and the second position.

[0018] Preferably, a plurality of first stop buckles are distributed along the length direction on the first clamping belt, so as to cooperate with each of the first stop buckles after the first stop buckles are matched with the first straps. The offset of the strips is limited.

[0019] Preferably, the first guide groove further includes a first assembly section and a first clamping section located at both ends of the first guide section.

[0020] Preferably, the first assembly section and the first clamping section extend along the axial direction of the grid, and the width of the first assembly section is greater than that of the first clamping section.

[0021] Preferably, the combination position of the first guide section and the first clamping section is provided with a first anti-release buckle that prevents the first clamping unit from sliding out of the first clamping section .

[0022] Preferably, the first assembly section penetrates to the edge of the first strip. [0023] Preferably, the elastic clamping mechanism includes a plurality of second clamping units, each of the second clamping units is arranged side by side with the first strip, and each of the second strips is passed through in turn;

[0024] Each of the second clamping units respectively forms the clamping portion in a row of the grids distributed along the extending direction of the first strip, and the second strip is provided with an alignment The second guiding structure for guiding the axial movement of the second clamping unit.

[0025] Preferably, the first guide structure and the second guide structure are staggered in the axial direction of the grid.

[0026] Preferably, the second clamping unit includes two symmetrically arranged second clamping bands to clamp the fuel rods from both sides;

[0027] The portion of the second clamping band of the second clamping unit located in the grid is provided with the clamping portion, the clamping portion is arc-shaped, and the second clamping unit The openings of the clamping parts of the two second clamping bands are opposite.

[0028] Preferably, the second guide structure includes a plurality of groups of second guide grooves alternately distributed along the length direction on each of the second strips and corresponding to each of the grid positions in a one-to-one manner. The second guide groove includes two symmetrical second guide grooves;

[0029] The two second clamping belts of each second clamping unit respectively pass through the corresponding second guide grooves of each group of the second guide grooves;

[0030] The second guide groove includes an inclined second guide section, which moves the elastic clamping mechanism laterally while moving in the axial direction of the grid, so that the clamping portion is at the same time. Switching between the first position and the second position;

[0031] A number of second limiting buckles are distributed along the length direction of the second clamping belt, so as to connect with each of the second straps after the second limiting buckles are matched with the second straps. Offset for limit.

[0032] Preferably, the second guide groove further includes a second assembly section and a second clamping section at both ends of the second guide section;

[0033] The second assembly section and the second clamping section extend along the axial direction of the grid, and the width of the second assembly section is greater than that of the second clamping section.

[0034] The combination position of the second guide section and the second clamping section is provided with a second anti-release buckle which prevents the second clamping unit from sliding out of the second clamping section.

[0035] A fuel assembly, including the positioning grid. The beneficial effects of the invention

Beneficial effect

[0036] The fuel assembly and the positioning grid of the present invention have the following beneficial effects: When the elastic clamping mechanism moves along the horizontal direction of the grid, the clamping part can be moved horizontally, opened for the insertion of fuel rods, and inserted The fuel rod is clamped and clamped by lateral movement to avoid scratches during the process of loading the fuel rod into the grid. The method of contacting the fuel rod after clamping makes the fuel rod and the clamping system abrasion risk The effective reduction is conducive to the stable surface contact between the fuel rod and the clamping system, and the overall safety of the fuel assembly is improved.

Brief description of the drawings

Description of the drawings

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the accompanying drawings:

[0038] FIG. 1 is a schematic structural diagram of a fuel assembly elastic clamping mechanism in an embodiment of the present invention when the clamping portion is in a first position;

[0039] FIG. 2 is a schematic structural diagram of the fuel assembly elastic clamping mechanism in the embodiment of the present invention when the clamping portion is in the second position;

[0040] FIG. 3 is a three-dimensional internal schematic diagram of the fuel assembly in FIG. 2;

[0041] FIG. 4 is a perspective schematic view of the clamping portion of the elastic clamping mechanism in FIG. 1 being assembled with the local positioning grid when the clamping portion is in the first position;

[0042] FIG. 5 is an assembly schematic diagram of the first clamping unit and the first strip in FIG. 4;

[0043] FIG. 6 is a schematic diagram of the structure when the first assembly section of the first guide groove penetrates to the edge of the first strip; [0044] FIG. 7 is the clamping part of the elastic clamping mechanism in FIG. 2 In the second position, the three-dimensional schematic diagram of the assembly with the local positioning grid.

Invention embodiment

Embodiments of the invention

[0045] In order to have a clearer understanding of the technical features, objectives and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0046] As shown in FIGS. 1 to 3, the fuel assembly in a preferred embodiment of the present invention includes a positioning grid 1. The rod 2, the positioning grid 1 includes a plurality of first strips 11 arranged side by side at intervals and a plurality of second strips 12 arranged side by side at intervals. The first belt 11 and the second belt 12 cross each other to form a plurality of fuel supply rods 2 Grid

[0047] Further, the positioning grid 1 further includes an elastic clamping mechanism 3, and the elastic clamping mechanism 3 includes a clamping portion 33 located in each grid.

[0048] The clamping portion 33 of the elastic clamping mechanism 3 can be switched between the first position A and the second position B in the transverse direction of the grid. When the clamping portion 33 of the elastic clamping mechanism 3 is in the first position A, it is close to the grid. In the inner wall of the grid, a channel larger than the outer diameter of the fuel rod 2 is formed; when the clamping portion 33 of the elastic clamping mechanism 3 is in the second position B, it is close to the center of the grid, and faces the fuel rods inserted in the grid 2 Form a clamp.

[0049] When the clamping portion 33 of the elastic clamping mechanism 3 moves along the transverse direction of the grid, the clamping portion 33 can be opened for the fuel rod 2 to be inserted, and the inserted fuel rod 2 can be clamped and moved laterally to the fuel rod 2. The clamping method prevents the fuel rod 2 from being scratched during the process of loading into the grid. The method of contacting the fuel rod 2 after clamping effectively reduces the risk of abrasion between the fuel rod 2 and the clamping system, which is beneficial to the fuel rod 2. It can form a stable surface contact with the clamping system to improve the overall safety of the fuel assembly.

[0050] The elastic clamping mechanism 3 includes a plurality of first clamping units 31 and a plurality of second clamping units 32, each of the first clamping unit 31 and the second strip 12 are arranged side by side, and each first strip is passed through in turn Belt 11; each second clamping unit 32 and the first belt 11 are arranged side by side, and each second belt 12 is passed through in turn.

[0051] As shown in FIG. 4 to FIG. 6, each first clamping unit 31 respectively forms a clamping portion 33 in a row of grids distributed along the extending direction of the second strip 12. The first strip 11 is provided with There is a first guide structure 111 that guides the lateral movement of the first clamping unit 31.

[0052] Each of the second clamping units 32 respectively forms a clamping portion 33 in a row of grids distributed along the extending direction of the first strip 11, and the second strip 12 is provided with a pair of the second clamping unit 32 The second guiding structure 121 that is guided by axial movement.

[0053] The first guide structure 111 and the second guide structure 121 are staggered in the axial direction of the grid and do not interfere with each other, so that the first clamping unit 31 and the second clamping unit 32 are in different axial directions of the fuel rod 2. Position for clamping and positioning.

[0054] The first clamping unit 31 includes two first clamping bands 311 symmetrically arranged to clamp the fuel rod 2 from both sides.

. In other embodiments, the first clamping unit 31 may also include only one first clamping band 311, and the fuel rod 2 is clamped against the side wall of the grid or other supporting structure by a first clamping band 311. tight. [0055] Preferably, the portion of the first clamping band 311 of the first clamping unit 31 located in the grid is provided with a clamping portion 33, the clamping portion 33 is arc-shaped, and the two first clamping units 31 The openings of the clamping portion 33 of the clamping band 311 face each other.

[0056] The two arc-shaped clamping portions 33 of the first clamping unit 31 can be wrapped from both sides of the fuel rod 2, and are in surface contact with the fuel rod 2, thereby improving the stability of clamping. The clamping portion 33 may also be in the shape of a V-shape, a U-shape or a flat plate. After clamping the fuel rod 2, it can form a line contact or a point contact with the fuel rod 2.

[0057] The first guide structure 111 includes a plurality of groups of first guide grooves 1111 distributed along the length direction of each first strip 11 and corresponding to each grid position one-to-one, and each group of first guide grooves 1111 includes a symmetrical Two first guide grooves 111

[0058] The two first clamping bands 311 of each first clamping unit 31 respectively pass through the corresponding first guide grooves 1111 of each set of first guide grooves 1111, so that one of the first guide grooves 1111 corresponds to a first clamp The movement of the holding belt 311 is guided, which facilitates separate control of the movement of the first holding belt 311.

[0059] In some embodiments, the first guide groove 1111 includes an inclined first guide section 1112, and the elastic clamping mechanism 3 is moved laterally while moving in the axial direction of the grid, so that the clamping portion 33 is Switch between the first position A and the second position B. The first guiding section 1112 is inclined, so that the first clamping belt 311 is laterally offset when moving in the axial direction of the grid, and clamps the side surface of the fuel rod 2. The first guiding section 1112 may also be an arc-shaped groove or a straight groove provided along the transverse direction of the grid, so that the first clamping belt 311 can move laterally.

[0060] In order to prevent the first clamping belt 311 from moving in the length direction after the first guide groove 1111 is inserted, a number of first stop buckles 3111 are distributed along the length direction on the first clamping belt 311, so as to The first retaining buckle 3111 cooperates with the first strap 11 to limit the position of each of the first straps 11, which can limit the length of the first clamping strap 311 in each grid.

[0061] The first guide groove 1111 further includes a first assembly section 1113 located at both ends of the first guide section 1112, a first clamping section 1114, and the first clamping band 311 passes through the first assembly section 1113 in advance, and the first clamp The holding belt 311 is located at the first position A, close to the inner wall of the grid, allowing the fuel rod 2 to be inserted, and then the first holding belt 311 is slid into the first clamping section 1114 along the first guide section 111 2 The clamping band 311 is located at the second position B, allowing the first clamping band 311 to clamp and fix the fuel rod 2.

[0062] Preferably, the first assembly section 1113 and the first clamping section 1114 extend along the axial direction of the grid to ensure that the side surface of the first clamping band 311 abuts against the fuel rod 2 to achieve surface contact. The width of the first assembly section 1113 is greater than that of the first clamping section 1114, which facilitates the initial insertion of the first clamping band 311 into the first guide groove 1111. At the same time, the first The width of the clamping section 1114 is small, which facilitates the fixed positioning of the first clamping band 311 and ensures stable clamping of the fuel rod 2.

[0063] In order to prevent the first clamping band 311 from sliding into the first guiding section 1112 along the first guide groove 1111 after being clamped into the first clamping section 1114, the first guiding section 1112 and the first clamping section The joint position of 1114 is provided with a first anti-release buckle 1115 that prevents the first clamping unit 31 from sliding out of the first clamping section 1114. Generally, the first anti-release buckle 1115 protrudes toward the first guide groove 1111 to face A clamping belt 311 is locked and positioned.

[0064] In some embodiments, the first assembly section 1113 penetrates to the edge of the first strip 11, so that the first clamping band 311 can be directly inserted from the opening position of the first assembly section 1113, which is beneficial to reduce the The length of a guide groove 1111 improves the strength of the grid. Preferably, due to the interference of the mixing wings on the positioning grid 1, the structure where the first assembly section 1113 penetrates to the edge of the first strip 11 can only be used when the first clamping belt 311 is installed from the lower part of the positioning grid 1的assembly.

[0065] As shown in FIG. 7, in some embodiments, the second clamping unit 32 includes two symmetrically arranged second clamping bands 321 to clamp the fuel rod 2 from both sides. In other embodiments, the second clamping unit 32 may also include only one second clamping band 321, and the fuel rod 2 is clamped against the side wall of the grid or other supporting structure by means of a second clamping band 321. tight.

[0066] The portion of the second clamping band 321 of the second clamping unit 32 located in the grid is provided with a clamping portion 33, the clamping portion 33 is arc-shaped, and the two second clamping bands of the second clamping unit 32 The openings of the clamping portion 33 of the 321 face each other.

[0067] The two arc-shaped clamping portions 33 of the second clamping unit 32 can be wrapped from both sides of the fuel rod 2, and are in surface contact with the fuel rod 2, thereby improving the stability of the clamping. Same as the clamping portion 33 of the first clamping unit 31, the clamping portion 33 of the second clamping unit 32 can also be V-shaped, U-shaped or flat. After clamping the fuel rod 2, it can be in contact with the fuel rod 2. Line contact and point contact are formed between.

[0068] The second guide structure 121 includes a plurality of groups of second guide grooves 1211 which are alternately distributed along the length direction of each second strip 12 and correspond to each grid position one-to-one. Each group of second guide grooves 1211 includes a symmetrical The two second guide grooves 1211.

[0069] The two second clamping bands 321 of each second clamping unit 32 respectively pass through the corresponding second guide grooves 1211 of each set of second guide grooves 1211, so that one of the second guide grooves 1211 corresponds to a second clamp The movement of the holding belt 321 is guided, which facilitates separate control of the movement of the second holding belt 321.

[0070] In some embodiments, the second guide groove 1211 includes an inclined second guide section 1212, which is opposed to the elastic clamping mechanism 3 Perform lateral movement while moving along the axial direction of the grid, so that the clamping portion 33 is switched between the first position A and the second position B. The second guiding section 1212 is inclined, so that the second clamping band 321 is laterally offset when moving in the axial direction of the grid, and clamps the side of the fuel rod 2. The second guiding section 1212 may also be an arc-shaped groove or a straight groove arranged along the transverse direction of the grid, so that the second clamping belt 321 can move laterally.

[0071] In order to prevent the second clamping belt 321 from moving in the length direction after passing through the second guide groove 1211, a number of second limiting buckles 3211 are distributed along the length direction on the second clamping belt 321 to The second limiting buckle 3211 cooperates with the second strap 12 to limit the position of each of the second straps 12, which can limit the length of the second clamping strap 321 in each grid.

[0072] The second guide groove 1211 further includes a second assembly section 1213 and a second clamping section 1214 located at both ends of the second guide section 1212. The second clamping band 321 passes through the second assembly section 1213 in advance, and the second clamp The holding belt 321 is located at the first position A, close to the inner wall of the grid, to allow the fuel rod 2 to be inserted, and then the second holding belt 321 is slid into the second clamping section 1214 along the second guiding section 1212. The clamping band 321 is located at the second position B, allowing the second clamping band 321 to clamp and fix the fuel rod 2.

[0073] The second assembly section 1213 and the second clamping section 1214 extend along the axial direction of the grid to ensure that the side surface of the second clamping band 321 abuts the fuel rod 2 to achieve surface contact. The width of the second assembly section 1213 is larger than that of the second clamping section 1214, which facilitates the initial insertion of the second clamping band 321 into the second guide groove 1211. At the same time, the width of the second clamping section 1214 is smaller, which is beneficial for fixing The second clamping band 321 is positioned to ensure stable clamping of the fuel rod 2.

[0074] In order to prevent the second clamping band 321 from sliding into the second guiding section 1212 along the second guide groove 1211 after being clamped into the second clamping section 1214, the second guiding section 1212 and the second clamping section The joint position of 1214 is provided with a second anti-release buckle 1215 that prevents the second clamping unit 32 from sliding out of the second clamping section 1214. Generally, the second anti-release buckle 1215 protrudes into the second guide groove 1211 to face the first The two clamping belts 321 are locked and positioned.

[0075] In this embodiment, the guiding direction of the first guiding groove 1111 and the second guiding groove 1211 is along the axial direction of the grid, and the guiding direction is opposite, that is, the elastic clamping mechanism 3 is switched to the first clamping of the fuel rod 2. In the second position B, the first clamping unit 31 moves upwards, the second clamping unit 32 moves downwards, and when the elastic clamping mechanism 3 switches to the first position A where the fuel rods 2 are released, the first clamping unit 31 moves toward When moving downward, the second clamping unit 32 moves upward to prevent the fuel rod 2 from being forced to move axially.

[0076] The guiding directions of the first guide groove 1111 and the second guide groove 1211 can also be the same. When the second clamping band 321 needs to be installed from the lower part of the positioning grid 1 into the second assembly section 1213, refer to FIG. 6, The second assembly section 1213 also runs through To the lower edge of the second strip 12.

[0077] In other embodiments, the elastic clamping mechanism 3 may also only include a plurality of first clamping units 31, or the elastic clamping mechanism 3 may only include a plurality of second clamping units 32.

[0078] It can be understood that the above technical features can be used in any combination without limitation.

[0079] The above are only the embodiments of the present invention, and do not limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the description and drawings of the present invention, or directly or indirectly applied to other Related technical fields are included in the scope of patent protection of the present invention in the same way.

Claims

[Claim 1] A fuel assembly positioning grid, comprising a plurality of first strips (11) arranged side by side at intervals and a plurality of second strips (12) arranged side by side at intervals, said first strips (11) and The second strips (12) cross each other to form a grid for the fuel rods (2) to pass through, characterized in that the positioning grid (1) also includes an elastic clamping mechanism (3);

The elastic clamping mechanism (3) includes a clamping portion (33) located in each of the grids; the clamping portion (33) of the elastic clamping mechanism (3) can be positioned in the transverse direction of the grid One position (A), the second position (B) conversion;

When the clamping portion (33) of the elastic clamping mechanism (3) is in the first position (A), a channel larger than the outer diameter of the fuel rod (2) is formed in the grid; When the clamping portion (33) of the clamping mechanism (3) is in the second position (B), it clamps the fuel rods (2) inserted in the grid.

[Claim 2] The positioning grid frame according to claim 1, wherein the elastic clamping mechanism (3) comprises a plurality of first clamping units (31), and each of the first clamping units (31) ) Arranged side by side with the second strip (12), and pass through each of the first strips (11) in turn;

Each of the first clamping units (31) respectively forms the clamping portion (33) in a row of the grids distributed along the extending direction of the second strip (12), and the first strip The belt (11) is provided with a first guiding structure (111) that guides the lateral movement of the first clamping unit (31).

[Claim 3] The positioning grid of claim 2, wherein the first clamping unit (3

1) Including two symmetrically arranged first clamping bands (311) to clamp the fuel rod (2) from both sides.

[Claim 4] The positioning grid of claim 3, wherein the first clamping unit (3

I) The first clamping belt (311) is provided with the clamping portion (33) in the part of the grid, the clamping portion (33) is arc-shaped, and the first clamping The openings of the clamping parts (33) of the two first clamping bands (311) of the unit (31) are opposite.

[Claim 5] The positioning grid of claim 4, wherein the first guide structure (1

II) Including the lengthwise distribution on each of the first strips (11), and the A number of groups of first guide grooves (1111) corresponding to the grid position one by one, each group of the first guide grooves (11 11) includes two symmetrical first guide grooves (1111);

The two first clamping belts (311) of each first clamping unit (31) respectively pass through the corresponding first guide grooves (1111) of each group of the first guide grooves (1111);

The first guide groove (1111) includes an inclined first guide section (1112), and the elastic clamping mechanism (3) is moved laterally while moving in the axial direction of the grid, so that the The clamping portion (33) is switched between the first position (A) and the second position (B).

[Claim 6] The positioning grid of claim 5, wherein the first clamping belt (311

) Are distributed along the length direction with a number of first stop buckles (3111), so that after the first stop buckle (3111) and the first strap (11) are matched with each of the first straps ( 11) The offset is limited.

[Claim 7] The positioning grid of claim 5, wherein the first guide groove (1111

) Also includes a first assembly section (1113) and a first clamping section (1114) located at both ends of the first guide section (1112).

[Claim 8] The positioning grid according to claim 7, wherein the first assembly section (111

3) The first clamping section (1114) extends along the axial direction of the grid, and the width of the first assembly section (1113) is greater than that of the first clamping section (1114).

[Claim 9] The positioning grid according to claim 7, wherein the first guiding section (111

2) The joint position with the first clamping section (1114) is provided with a first anti-release buckle (1115) that prevents the first clamping unit (31) from sliding out of the first clamping section (1114) ).

[Claim 10] The positioning grid according to claim 7, wherein the first assembly section (111

3) Pass through to the edge of the first strip (11).

[Claim 11] The positioning grid according to any one of claims 2 to 10, wherein the elastic clamping mechanism (3) comprises a plurality of second clamping units (32), each of the second clamping units (32) The clamping unit (32) is arranged side by side with the first strip (11), and each of the second strips (12) is passed through in turn;

Each of the second clamping units (32) is divided along the extension direction of the first strip (11) The clamping portions (33) are respectively formed in a row of the grids of the cloth, and the second strip (12) is provided with a first guiding the axial movement of the second clamping unit (32). Two guiding structure (121).

[Claim 12] The positioning grid according to claim 11, wherein the first guide structure (111) and the second guide structure (121) are staggered in the axial direction of the grid.

[Claim 13] The positioning grid according to claim 11, wherein the second clamping unit (

32) Including two second clamping bands (321) symmetrically arranged to clamp the fuel rod (2) from both sides;

The portion of the second clamping band (321) of the second clamping unit (32) located in the grid is provided with the clamping portion (33), and the clamping portion (33) is in an arc The openings of the clamping portions (33) of the two second clamping bands (321) of the second clamping unit (32) are opposite to each other.

[Claim 14] The positioning grid according to claim 13, wherein the second guiding structure (

121) Including a number of sets of second guide grooves (1211) alternately distributed along the length direction on each of the second strips (12) and corresponding to each grid position one-to-one, and each set of the second guide grooves (1211) The groove (1211) includes two symmetrical second guide grooves (1211);

The two second clamping belts (321) of each second clamping unit (32) respectively pass through the corresponding second guide grooves (1211) of each group of the second guide grooves (1211); The second guide groove (1211) includes an inclined second guide section (1212), and the elastic clamping mechanism (3) is moved laterally while moving in the axial direction of the grid, so that the The clamping portion (33) is switched between the first position (A) and the second position (B);

A plurality of second limiting buckles (3211) are distributed along the length direction of the second clamping belt (321), so that after the second limiting buckle (3211) is matched with the second strap (12) Limit the offset with each of the second strips (12).

[Claim 15] The positioning grid according to claim 14, wherein the second guide groove (1211

) It also includes a second assembly section (1213) and a second clamping section (1214) located at both ends of the second guide section (1212); The second assembly section (1213) and the second clamping section (1214) extend along the axial direction of the grid, and the width of the second assembly section (1213) is larger than that of the second clamping section (1214)

);

The joint position of the second guiding section (1212) and the second clamping section (1214) is provided with a device that prevents the second clamping unit (32) from sliding out of the second clamping section (1214) The second anti-dropping buckle (1215).

[Claim 16] A fuel assembly, characterized in that it comprises the positioning grid (1) according to any one of claims 1 to 15.