A fuel assembly skeleton connection structure and a fuel assembly skeleton

Abstract

The present invention belongs to the technical field of fuel assemblies, and specifically relates to a fuel assembly skeleton connection structure and a fuel assembly skeleton. In the skeleton connection structure of the present invention, the guide tube runs through the grid element of the positioning grid, and the guide tube and the grid element of the positioning grid are connected by welding contact to form an integrated fixed structure; in the fuel assembly skeleton of the present invention, the grid element of the positioning grid is a four-sided cylinder, and upper slots are respectively provided on the four faces of the grid element for matching the plug-in connection, and the plug-in includes a clamping part and a plug-in part, and the clamping part protrudes toward the inner side of the grid element. The present invention can effectively prevent the guide tube from falling off and loosening, and improve the life cycle and operation stability of the guide tube.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel assemblies, and in particular relates to a fuel assembly skeleton connection structure and a fuel assembly skeleton. Background Art

[0002] The fuel assembly is the core component that generates heat in a nuclear reactor, and its design is related to the safety, reliability and economy of the nuclear reactor.

[0003] The guide tubes, positioning grids, upper tube seats and lower tube seats in the fuel assembly constitute the fuel assembly skeleton: a number of guide tubes penetrate the grid elements of the positioning grid from top to bottom, the upper ends of the guide tubes are fixedly connected to the upper tube seats, and the lower ends of the guide tubes are fixedly connected to the lower tube seats.

[0004] In the prior art, the method of accurately controlling the size of the grid element of the spacer frame and the size of the outer wall of the guide tube is generally adopted to make the guide tube stuck in the grid element of the spacer frame to achieve a fixed connection between the guide tube and the spacer frame. The disadvantage of this fixed connection is that it is easy to cause the guide tube to loosen and cause wear on the outer surface of the guide tube, affecting the life cycle and operation stability of the guide tube. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the fixed connection method between the guide tube and the positioning grid in the prior art easily leads to loosening of the guide tube and causes wear on the outer surface of the guide tube, thus affecting the life cycle and operation stability of the guide tube.

[0006] The technical solution of the present invention is as follows:

[0007] A fuel assembly skeleton connection structure, wherein a guide tube runs through a positioning grid element, and the guide tube and the positioning grid element are connected by welding contact to form an integrated fixed structure.

[0008] As a preferred solution: a sleeve is embedded outside the guide tube at the spacer grid: the sleeve and the guide tube are fixed by welding or expansion; the sleeve and the spacer grid are fixed by welding. As a further preferred solution: the sleeve and the spacer grid are in surface contact, and the contact part is fixed by welding.

[0009] As a preferred solution: it also includes two metal rings, which are sleeved on the outside of the guide tube and are respectively located on the upper end face and the lower end face of the positioning grid element through which the guide tube passes. The outer diameter of the metal ring is larger than the aperture of the positioning grid element, that is, the two metal rings clamp the guide tube in the positioning grid element.

[0010] As a preferred solution: fins are provided on the inner walls of the upper and lower end surfaces of the spacer grid element, and the fins are welded to the outer wall of the guide tube penetrating the spacer grid element.

[0011] As a preferred solution, the guide tube and the spacer grid element are connected by spot welding. As a further preferred solution, each side of the spacer grid element is connected by welding with the outer wall of the contacting guide tube by two welding points symmetrically distributed relative to the guide tube.

[0012] As a preferred solution: the guide tube and the spacer grid element are connected by strip welding.

[0013] A fuel assembly skeleton comprises a guide tube, a positioning grid, an upper tube seat and a lower tube seat, wherein a plurality of guide tubes penetrate from top to bottom in a grid element of the positioning grid, wherein the upper end of the guide tube is fixedly connected to the upper tube seat, and the lower end of the guide tube is fixedly connected to the lower tube seat; the guide tube and the positioning grid directly adopt any one of the above-mentioned fuel assembly skeleton connection structures; the grid element of the positioning grid is a four-sided cylinder, wherein upper slots are respectively arranged on the four faces of the grid element for matching with plug-in plug-in, and the plug-in comprises a clamping portion and a plug-in portion, and the clamping portion protrudes toward the inner side of the grid element.

[0014] As a preferred solution: the plug-in is an angle plug-in, which includes a clamping portion and two plug-in portions, wherein the two plug-in portions are perpendicular to each other, and the clamping portion is arranged between the two plug-in portions.

[0015] As a preferred solution: the plug-in is an edge plug-in, which includes two clamping parts and three plug-in parts, the three plug-in parts are in a T shape, and the clamping parts are respectively arranged at a right angle between every two plug-in parts.

[0016] As a preferred solution: the plug-in is a channel plug-in, which includes three clamping parts and four plug-in parts, the four plug-in parts are in a cross shape, and the clamping part is arranged between every two plug-in parts.

[0017] As a preferred solution: the plug-in is an intermediate plug-in, which includes four clamping parts and four plug-in parts, the four plug-in parts are in a cross shape, and the clamping part is arranged between every two plug-in parts.

[0018] The beneficial effects of the present invention are:

[0019] (1) In the fuel assembly skeleton connection structure of the present invention, the spacer grid and the guide tube are connected by welding, which can effectively prevent the guide tube from falling off and loosening;

[0020] (2) The fuel assembly skeleton connection structure of the present invention can significantly reduce the wear of the spacer grid on the outer wall of the guide tube, effectively improving the life cycle and operating stability of the guide tube;

[0021] (3) In the fuel assembly skeleton connection structure of the present invention, the sleeve in Example 3 is in surface contact with the spacer grid, which greatly increases the contact area and further improves the connection reliability;

[0022] (4) The design of the positioning grid of the fuel assembly skeleton of the present invention is not only applicable to common rod-shaped fuel assemblies, but also to fuel elements with a larger outer diameter, such as annular fuel elements, so that the coolant and the fuel element can be more fully contacted, the fuel element can be horizontally positioned, and a certain stirring effect can be produced on the coolant;

[0023] (5) The fuel assembly skeleton of the present invention uses plug-ins to clamp and support the fuel elements, which significantly enhances the overall rigidity and simplifies the processing procedures of the support parts of the spacer grid, thereby reducing the processing difficulty;

[0024] (6) In the fuel assembly skeleton of the present invention, a gap is provided between the side surface of the plug-in plug-in portion and the side surface of the grid element, so that the clamping force value range of the clamping portion is increased, which can meet the working requirements under different conditions;

[0025] (7) The fuel assembly skeleton of the present invention can avoid the problem of welding dissimilar materials when the grid element and the plug-in are made of different materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the fuel assembly skeleton connection structure in Example 1;

[0027] Figure 2 for Figure 1 A top view of

[0028] Figure 3 This is a schematic diagram of the fuel assembly skeleton connection structure in Example 2;

[0029] Figure 4 is a schematic diagram of the positioning grid structure;

[0030] Figure 5 For angular plugin intention;

[0031] Figure 6 This is a schematic diagram of the edge plug-in;

[0032] Figure 7 This is a schematic diagram of the intermediate plug-in.

[0033] In the figure, 1-positioning grid element, 2-guide tube, 3-welding point, 4-clamping part, 5-plug-in part, 6-corner plug-in, 7-side plug-in, 8-channel plug-in, 9-middle plug-in, 10-plug-in, 11-outer strip, 12-guide wing, 13-guide tube channel. DETAILED DESCRIPTION

[0034] The fuel assembly skeleton connection structure of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0035] In the fuel assembly skeleton connection structure of the present invention, the guide tube 2 and the spacer grid element 1 are connected by welding to form an integrated fixed structure.

[0036] Example 1

[0037] Existing spacer grid elements 1 are generally polygonal structures, such as hexagonal grid elements and Figure 2 The quadrilateral grid element shown. For the spacer grid element 1 through which the guide tube 2 passes, the guide tube 2 and the spacer grid element 1 are connected by spot welding. For example, for each side of the spacer grid element 1, two welding points 3 are used to weld and connect with the outer wall of the contacting guide tube 2. As a preferred embodiment, the two welding points 3 on each side of the spacer grid element 1 are symmetrically distributed relative to the guide tube 2. This design can further prevent the guide tube 2 from falling off and loosening.

[0038] Example 2

[0039] In the fuel assembly skeleton connection structure of this embodiment, the sleeve is nested outside the guide tube 2 at the spacer grid. The sleeve and the guide tube 2 can be fixed by welding or expansion; the sleeve and the spacer grid are in surface contact, and the contact part is fixed by welding.

[0040] Example 3

[0041] The skeleton connection structure in this embodiment includes two metal rings. The two metal rings are sleeved on the outside of the guide tube 2 and are respectively located on the upper end face and the lower end face of the spacer grid element 1 through which the guide tube 2 passes. The outer diameter of the metal rings is slightly larger than the aperture of the spacer grid element 1, that is, the two metal rings clamp the guide tube 2 in the spacer grid element 1 to achieve the connection between the guide tube 2 and the spacer grid.

[0042] Example 4

[0043] In the skeleton connection structure of this embodiment, fins are arranged on the inner walls of the upper and lower end surfaces of the spacer grid element 1, and the connection between the guide tube 2 and the spacer grid is achieved by welding the fins to the outer wall of the guide tube 2 penetrating the spacer grid element 1.

[0044] Example 5

[0045] For the spacer grid element 1 through which the guide tube 2 penetrates, the guide tube 2 and the spacer grid element 1 are connected by strip welding.

[0046] Example 6

[0047] A fuel assembly skeleton in this embodiment includes a guide tube 2, a positioning grid, an upper tube seat and a lower tube seat. A plurality of guide tubes 2 are inserted into the grid element of the positioning grid from top to bottom. The upper end of the guide tube 2 is fixedly connected to the upper tube seat, and the lower end of the guide tube 2 is fixedly connected to the lower tube seat. The guide tube 2 and the positioning grid directly adopt any one of the fuel assembly skeleton connection structures in Examples 1 to 5; the grid element 1 of the positioning grid is a four-sided cylinder, and upper slots are respectively provided on the four faces of the grid element 1 for matching with the plug-in 10 for plugging. The plug-in 10 includes a clamping portion 4 and a plug-in portion 5, and the clamping portion 4 protrudes toward the inner side of the grid element 1.

[0048] The plug-in 10 includes a corner plug-in 6, a side plug-in 7, a channel plug-in 8 and a middle plug-in 9. The corner plug-in 6 includes a clamping portion 4 and two plug-in portions 5, wherein the two plug-in portions 5 are perpendicular to each other, and the clamping portion 4 is arranged between the two plug-in portions 5. The side plug-in 7 includes two clamping portions 4 and three plug-in portions 5, wherein the three plug-in portions 5 are in a T-shape, and the clamping portions 4 are respectively arranged at right angles between every two plug-in portions 5. The channel plug-in 8 includes three clamping portions 4 and four plug-in portions 5, wherein the four plug-in portions 5 are in a cross shape, and the clamping portion 4 is arranged between every two plug-in portions 5. The middle plug-in 9 includes four clamping portions 4 and four plug-in portions 5, wherein the four plug-in portions 5 are in a cross shape, and the clamping portion 4 is arranged between every two plug-in portions 5.

Claims

1. A fuel assembly skeleton connection structure, wherein a guide tube (2) penetrates through a spacer grid element (1), characterized in that: The guide tube (2) and the positioning grid element (1) are connected by welding contact to form an integrated fixed structure; a sleeve is nested outside the guide tube (2) at the positioning grid: the sleeve and the guide tube (2) are fixed by welding or expansion connection; the sleeve and the positioning grid are in surface contact, and the contact part is fixed by welding; two metal rings are sleeved on the outside of the guide tube (2), respectively located on the upper end face and the lower end face of the positioning grid element (1) through which the guide tube (2) passes, and the outer diameter of the metal rings is larger than the aperture of the positioning grid element (1), that is, the two metal rings clamp the guide tube (2) in the positioning grid element (1).

2. The fuel assembly skeleton connection structure according to claim 1, characterized in that: Wings are arranged on the inner walls of the upper and lower end surfaces (1) of the spacer grid element, and the wing is welded and connected to the outer wall of the guide tube (2) penetrating the spacer grid element (1).

3. The fuel assembly skeleton connection structure according to claim 1, characterized in that: The guide tube (2) and the spacer grid element (1) are connected by strip welding.

4. The fuel assembly skeleton connection structure according to claim 3, characterized in that: For each side of the spacer grid element (1), two welding points (3) symmetrically distributed relative to the guide tube (2) are used to weld and connect with the outer wall of the guide tube (2) in contact.

5. The fuel assembly skeleton connection structure according to claim 1, characterized in that: The guide tube (2) and the spacer grid element (1) are connected by means of strip welding.

6. A fuel assembly skeleton, comprising a guide tube (2), a spacer grid, an upper tube seat and a lower tube seat, wherein a plurality of guide tubes (2) penetrate from top to bottom in a grid element of the spacer grid, the upper end of the guide tube (2) is fixedly connected to the upper tube seat, and the lower end of the guide tube (2) is fixedly connected to the lower tube seat, characterized in that: The guide tube (2) and the spacer grid directly adopt any one of the fuel assembly skeleton connection structures in claim 1 to claim 5; The grid element of the positioning grid is a four-sided cylinder, and upper slots are respectively arranged on the four faces of the grid element for matching the plug-in plug-in. The plug-in includes a clamping part and a plug-in part, and the clamping part protrudes toward the inner side of the grid element.

7. A fuel assembly skeleton according to claim 6, characterized in that: The plug-in unit is an angle plug-in unit, which comprises a clamping portion and two plug-in portions, wherein the two plug-in portions are perpendicular to each other, and the clamping portion is arranged between the two plug-in portions.

8. A fuel assembly skeleton according to claim 6, characterized in that: The plug-in is a side plug-in, which comprises two clamping parts and three plug-in parts, the three plug-in parts are in a T-shape, and the clamping parts are respectively arranged at right angles between every two plug-in parts.

9. A fuel assembly skeleton according to claim 6, characterized in that: The plug-in is a channel plug-in, which comprises three clamping parts and four plug-in parts. The four plug-in parts are in a cross shape, and the clamping part is arranged between every two plug-in parts.

10. A fuel assembly skeleton according to claim 6, characterized in that: The plug-in is an intermediate plug-in, which comprises four clamping parts and four plug-in parts. The four plug-in parts are in a cross shape, and the clamping part is arranged between every two plug-in parts.

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