Positioning device for hexagonal fuel assembly

Abstract

The utility model belongs to the technical field of nuclear-grade assembly manufacturing, and particularly relates to a positioning device for a hexagonal fuel assembly. The positioning device comprises a positioning piece, a bottom plate and a clamping mechanism, the positioning piece and the clamping mechanism are fixed on the bottom plate; the clamping mechanism is used for clamping a hexagonal fuel assembly to be operated; the positioning piece is of a cylindrical structure, the length of the positioning piece is matched with that of the hexagonal fuel assembly, and the positioning piece is used for limiting the hexagonal fuel assembly. After the positioning device is applied to fuel assembly welding, the positioning precision is obviously improved, the problem that two structural parts are difficult to position is solved, and the problems of downtime and structural part and fuel rod damage caused by poor positioning precision are also solved.

Description

Technical Field

[0001] This application belongs to the field of nuclear-grade component manufacturing technology, specifically relating to a positioning device for hexagonal fuel assemblies. Background Technology

[0002] M-fuel is short for oxide fuel mixture, and its development is an essential requirement for implementing a closed-cycle nuclear fuel strategy. M-fuel has the following advantages: it can improve resource utilization and solve the problem of insufficient nuclear fuel resources; it is also beneficial to environmental protection.

[0003] Module assembly is the final process in M-module production, undertaking crucial tasks such as fuel rod bundle assembly, module alignment, and module welding. Module welding consists of two welds: one between the upper operating head and the outer sleeve, and the other between the lower transition joint and the outer sleeve. Due to the unique welding structure and position, in the upper operating head weld, molten metal undergoes droplet transfer. During welding, molten metal transfers towards the hexagonal tube. During this transfer, the molten metal flows towards the relatively thinner hexagonal tube, resulting in undercut. However, this phenomenon does not occur between the lower tube and the hexagonal tube because the molten metal flows from the thinner hexagonal tube to the thicker transition joint, preventing undercut.

[0004] In addition, inaccurate positioning can occur when using assembly trusses for material loading. Inaccurate positioning can damage structural components and fuel rods. Since fuel rods contain radioactive materials, they are strategic national resources. Therefore, the losses caused by inaccurate positioning during the production stage are unbearable. Utility Model Content

[0005] The purpose of this application is to provide a positioning device for hexagonal fuel assemblies, which solves the problem of inaccurate positioning during the production stage in the prior art.

[0006] The technical solution to achieve the purpose of this application is as follows:

[0007] This application provides a positioning device for a hexagonal fuel assembly, the positioning device comprising: a positioning element, a base plate, and a clamping mechanism;

[0008] Both the positioning element and the clamping mechanism are fixed to the base plate; the clamping mechanism is used to clamp the hexagonal fuel assembly to be operated;

[0009] The positioning element is a cylindrical structure, the length of which matches the length of the hexagonal fuel assembly, and is used to limit the position of the hexagonal fuel assembly.

[0010] Optionally, the positioning device further includes: a positioning plate;

[0011] The lower end of the positioning plate is fixed to the base plate, and the upper end has a through hole. The positioning component is fixed in the through hole by a pin.

[0012] Optionally, before use, one end of the positioning member is fixed in the through hole, and the other end is away from the clamping mechanism; during use, the other end of the positioning member is fixed in the through hole, and the other end is located between the positioning plate and the clamping mechanism.

[0013] Optionally, the distance between the positioning plate and the clamping mechanism is 302mm, and the length of the positioning element is 197mm.

[0014] Optionally, the positioning device further includes: a drive mechanism;

[0015] The drive mechanism is used to move the base plate toward the hexagonal fuel assembly.

[0016] Optionally, the positioning device further includes: a hard limit;

[0017] A hard limiter is provided on the base plate to limit the distance between the base plate and the hexagonal fuel assembly.

[0018] Optionally, the rear end of the clamping mechanism is hexagonal and the front end is arc-shaped to fit the characteristics of the operating head and the pins.

[0019] The beneficial technical effects of this application are as follows:

[0020] This application provides a positioning device for a hexagonal fuel assembly, comprising: a positioning element, a base plate, and a clamping mechanism; both the positioning element and the clamping mechanism are fixed to the base plate; the clamping mechanism is used to clamp the hexagonal fuel assembly to be operated; the positioning element is a cylindrical structure, the length of which matches the length of the hexagonal fuel assembly, for limiting the position of the hexagonal fuel assembly. After the fuel assembly is welded, this positioning device significantly improves the positioning accuracy, not only solving the problem of difficult positioning of the two structural components, but also solving the problems of downtime and damage to structural components and fuel rods caused by poor positioning accuracy. This brings huge cost savings to subsequent assembly production. Attached Figure Description

[0021] Figure 1 A schematic diagram of a positioning device for a hexagonal fuel assembly provided in an embodiment of this application;

[0022] Figure 2a and Figure 2b This is a schematic diagram showing the usage state of a positioning device for a hexagonal fuel assembly, provided in an embodiment of this application.

[0023] In the picture:

[0024] 1-Positioning component; 2-Pin; 3-Drive mechanism; 4-Base plate; 5-Hard limit; 6-Clamping mechanism; 7-Positioning plate. Detailed Implementation

[0025] To enable those skilled in the art to better understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only a part of the embodiments of this application, and not all of them. Based on the embodiments described in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] See Figure 1 The figure is a schematic diagram of a positioning device for a hexagonal fuel assembly provided in an embodiment of this application.

[0027] This application provides a positioning device for a hexagonal fuel assembly, comprising: a positioning element 1, a base plate 4, and a clamping mechanism 6;

[0028] Both the positioning component 1 and the clamping mechanism 6 are fixed on the base plate 4; the clamping mechanism 6 is used to clamp the hexagonal fuel assembly to be operated;

[0029] Positioning element 1 is a cylindrical structure, the length of which matches the length of the hexagonal fuel assembly, and is used to limit the position of the hexagonal fuel assembly.

[0030] In this embodiment, the clamping mechanism 6 clamps the hexagonal fuel assembly to be operated, and the positioning element 1 limits its position to ensure positioning accuracy during operation.

[0031] In some possible implementations of the embodiments of this application, the positioning device may further include: a positioning plate 7;

[0032] The lower end of the positioning plate 7 is fixed on the base plate 4, and the upper end has a through hole. The positioning component 1 is fixed in the through hole by a pin 2.

[0033] In one example, before use, one end of the positioning member 1 is fixed in the through hole, and the other end is away from the clamping mechanism 6; during use, the other end of the positioning member 1 is fixed in the through hole, and the other end is located between the positioning plate 7 and the clamping mechanism 6.

[0034] In practical applications, when welding hexagonal fuel assemblies is required, simply lift pin 2 and reverse the orientation of positioning element 1 to position the hexagonal fuel assembly for welding. Figure 2a and 2b As shown.

[0035] In another example, the distance between the positioning plate 7 and the clamping mechanism 6 is 302mm, and the length of the positioning element 1 is 197mm.

[0036] Understandably, by adjusting the distance of the clamping mechanism 6 and the length of the positioning component 1 based on the dimensional difference between the hexagonal fuel assemblies, the positioning accuracy has been significantly improved. This not only solves the problem of difficult positioning of the two structural components, but also solves the problem of downtime and damage to structural components and fuel rods caused by poor positioning accuracy.

[0037] In some possible implementations of the embodiments of this application, the positioning device may further include: a driving mechanism 3;

[0038] The drive mechanism 3 is used to move the base plate 4 toward the hexagonal fuel assembly.

[0039] In one example, the drive mechanism 3 can be driven using a cylinder.

[0040] In some possible implementations of the embodiments of this application, the positioning device may further include: a hard limit 5;

[0041] A hard limiter 5 is provided on the base plate 4 to limit the distance between the base plate 4 and the hexagonal fuel assembly.

[0042] It is understandable that a hard limit 5 is added to the travel direction of the base plate 4 to prevent damage to the hexagonal fuel assembly due to excessive power from the drive mechanism 3.

[0043] In one example, the rear end of the clamping mechanism 6 is hexagonal and the front end is arc-shaped to fit the characteristics of the operating head and the pin, ensuring firm clamping without damaging the component structure and improving positioning accuracy during assembly.

[0044] After the device was applied to fuel assembly welding, the positioning accuracy of each assembly was measured four times. The test results are shown in Table 1. The coaxiality test results at various points before and after assembly installation are shown in Table 2.

[0045] Table 1. Repeatability test table after application.

[0046]

[0047]

[0048] Table 2. Coaxiality Test Table of Various Parts of the Device After Application

[0049]

[0050] Compared to before the application, the positioning accuracy has been significantly improved. This not only solved the problem of difficult positioning for the two structural components, but also resolved the issues of downtime and damage to structural components and fuel rods caused by poor positioning accuracy. This has resulted in substantial cost savings for subsequent component production.

[0051] This application provides a positioning device for a hexagonal fuel assembly, comprising: a positioning element, a base plate, and a clamping mechanism; both the positioning element and the clamping mechanism are fixed to the base plate; the clamping mechanism is used to clamp the hexagonal fuel assembly to be operated; the positioning element is a cylindrical structure, the length of which matches the length of the hexagonal fuel assembly, used to limit the position of the hexagonal fuel assembly. After welding the fuel assembly, this positioning device fixes the position of the hexagonal fuel assembly, thereby fixing the weld position and significantly improving positioning accuracy. It not only solves the problem of difficult positioning of the two structural components but also solves the problems of downtime and damage to structural components and fuel rods caused by poor positioning accuracy. It greatly improves the weld quality of the upper operating head, laying a solid foundation for mass production of the assembly and bringing significant cost savings to subsequent assembly production.

[0052] The present application has been described in detail above with reference to the accompanying drawings and embodiments. However, the present application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present application. All content not described in detail in this application can be derived from existing technology.

Claims

1. A positioning device for a hexagonal fuel assembly, characterized in that, The positioning device comprises a positioning member (1), a bottom plate (4) and a clamping mechanism (6); The positioning member (1) and the clamping mechanism (6) are both fixed on the bottom plate (4); the clamping mechanism (6) is used for clamping a hexagonal fuel assembly to be operated; The positioning member (1) is in a cylindrical structure, and its length matches the length of the hexagonal fuel assembly, and is used for limiting the hexagonal fuel assembly.

2. The spacer grid for hexagonal fuel assemblies according to claim 1, characterized in that, The positioning device further comprises a positioning plate (7); The lower end of the positioning plate (7) is fixed on the bottom plate (4), and the upper end is provided with a through hole; the positioning member (1) is fixed in the through hole through a bolt (2).

3. The spacer grid for hexagonal fuel assemblies according to claim 2, characterized in that, Before use, one end of the positioning member (1) is fixed in the through hole, and the other end is away from the clamping mechanism (6); during use, the other end of the positioning member (1) is fixed in the through hole, and one end is located between the positioning plate (7) and the clamping mechanism (6).

4. The spacer grid for hexagonal fuel assemblies according to claim 3, characterized in that, The distance between the positioning plate (7) and the clamping mechanism (6) is 302 mm, and the length of the positioning member (1) is 197 mm.

5. The spacer grid for hexagonal fuel assemblies according to claim 1, characterized in that, The positioning device further comprises a driving mechanism (3); The driving mechanism (3) is used for driving the bottom plate (4) to move towards the hexagonal fuel assembly.

6. The spacer grid for hexagonal fuel assemblies according to claim 5, characterized in that, The positioning device further comprises a hard stop (5); The hard stop (5) is arranged on the bottom plate (4) and is used for limiting the distance between the bottom plate (4) and the hexagonal fuel assembly.

7. A spacer grid for hexagonal fuel assemblies according to any one of claims 1-6, characterized in that The rear end of the clamping mechanism (6) is in a hexagonal structure, and the front end is in a circular arc structure, so as to match the characteristics of the operating head and the pin.

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