A guide tube assembly with detachable expansion joint and a simulated skeleton

Abstract

The present invention belongs to the manufacturing technology of nuclear fuel assembly, and specifically relates to a guide tube assembly with a detachable expansion joint and a simulation skeleton, including a sleeve, a sleeve connector, a guide tube and an end plug; the two ends of the guide tube are thin-walled ends, the end plug is fixedly connected to one thin-walled end of the guide tube, one end of the sleeve connector is threadedly connected to the other thin-walled end of the guide tube, and the other end is arranged in the sleeve. The simulation skeleton consists of 24 guide tube assemblies, two end grids, a plurality of mixing grids, a plurality of middle mixing grids and a lower tube seat. The expanded sleeve part can be disassembled, and a new sleeve can be reinstalled and tested again, so as to complete multiple tests at a relatively low cost.

Description

Technical Field

[0001] The invention belongs to nuclear fuel assembly manufacturing technology, and in particular relates to a simulation part in experimental research on assembly skeleton expansion process. Background Art

[0002] Skeleton expansion is the key process in the manufacture of 17X17 skeletons. There are two types of skeleton expansion processes: single-branch expansion and overall expansion. Overall expansion is an advanced process technology for the production and manufacturing of nuclear fuel assembly skeletons at home and abroad. It can realize the one-time expansion of 24 guide tubes and 24 sleeves of the fuel assembly skeleton. It has the remarkable characteristics of consistent expansion and higher production efficiency. It is the development direction of AFA3G fuel assembly skeleton manufacturing technology.

[0003] The purpose of skeleton expansion is to firmly connect the sleeve to the skeleton guide tube, which serves as a "bridge" between the skeleton and the tube seat on the assembly. The skeleton expansion is achieved by moving the tapered expansion rod to the right, and using the change in the diameter of the expansion rod to open the expansion sleeve outside the expansion rod, generating a large enough radial expansion force, so that the external guide tube and the sleeve will produce plastic deformation in turn, so that the two are tightly combined together to complete the skeleton expansion work.

[0004] After the overall expansion of the skeleton is completed, the flatness of the 24 sleeve end faces is no more than 0.15mm. This technical indicator is an important inspection item in the quality of the skeleton product, which is directly related to the length of the skeleton and the length difference of the fuel assembly. The flatness test and verification of the 24 sleeve end faces must be tested on the skeleton after welding, and must be guaranteed by the overall expansion device. To debug and determine the key expansion parameters of the overall expansion device (determination of expansion pressure, expansion time, etc.) and the expansion effect, multiple groups of finished skeletons must be used for testing and verification. Each group of finished skeletons can only be tested once. The cost of a group of skeletons is about 300,000. The huge test cost will result in the consumption of a large amount of professional raw materials. When the expansion quality of the skeleton expansion device is unstable, it is also necessary to test on the finished skeleton to verify the debugging effect of the device, which will also result in the consumption of a large amount of professional raw materials. At this stage, the debugging and debugging effect of the overall expansion device must be verified at a high cost.

[0005] The finished skeleton is used to carry out the debugging test of the integral expansion device. One test will consume 11 grids and 24 guide tubes, which is very costly. In order to avoid the loss of a large amount of professional raw materials due to the test, it is necessary to simulate the formal skeleton. Summary of the invention

[0006] The purpose of the present invention is to provide a simulated frame of a detachable expansion joint part, which is used for debugging of an overall expansion joint device or verification of the device during production.

[0007] The technical solution of the present invention is as follows:

[0008] A guide tube assembly with a detachable expansion joint comprises a sleeve, a sleeve connector, a guide tube and an end plug; the two ends of the guide tube are thin-walled ends, the end plug is fixedly connected to one thin-walled end of the guide tube, one end of the sleeve connector is threadedly connected to the other thin-walled end of the guide tube, and the other end of the sleeve connector is arranged in the sleeve.

[0009] The end plug comprises a frustum in the middle, and a cylindrical part and a conical part located on both sides of the frustum, the cylindrical part is located in the guide tube, and the frustum is clamped at the end of the guide tube.

[0010] The outermost diameters of the sleeve connector, the guide tube and the end plug are the same.

[0011] The sleeve comprises two sections with different diameters but the same wall thickness. The outer surfaces of the connecting parts of the two sections are processed into a conical surface transition, and the inner part is processed into a step structure. The sleeve connector is axially positioned with the sleeve through the step structure.

[0012] A simulated skeleton of a detachable expansion joint portion consists of 24 guide tube assemblies, two end grids, a plurality of mixing grids, a plurality of middle mixing grids and a lower tube seat. The guide tube assembly passes through the end grids, the mixing grids and the middle mixing grids, and the end of the guide tube assembly is fixedly connected to the lower tube seat.

[0013] The guide tube assembly includes a sleeve, a sleeve connector, a guide tube and an end plug; the two ends of the guide tube are thin-walled ends, the end plug is fixedly connected to one thin-walled end of the guide tube, one end of the sleeve connector is threadedly connected to the other thin-walled end of the guide tube, and the other end of the sleeve connector is installed in the sleeve.

[0014] The end plug comprises a frustum in the middle, and a cylindrical part and a conical part located on both sides of the frustum, the cylindrical part is located in the guide tube, and the frustum is clamped at the end of the guide tube.

[0015] The outermost diameters of the sleeve connector, the guide tube and the end plug are the same.

[0016] The sleeve comprises two sections with different diameters but the same wall thickness. The outer surfaces of the connecting parts of the two sections are processed into a conical surface transition, and the inner part is processed into a step structure. The sleeve connector is axially positioned with the sleeve through the step structure.

[0017] The guide tube is fixed to the end grid, the mixing grid and the middle mixing grid by welding respectively.

[0018] The remarkable effects of the present invention are as follows:

[0019] The simulated frame of the expansion joint can be disassembled, and the expanded sleeve part can be disassembled, and a new sleeve can be reinstalled and tested again, so as to complete multiple tests at a relatively low cost.

[0020] The simulated skeleton at the detachable expansion part has the same dimensions as the production skeleton, and the expansion part of the skeleton is designed to be a detachable structure with threaded connection. After a set of tests are completed, the expanded part can be removed, and then a new test sleeve can be reinstalled to repeat the next round of tests. Using the simulated skeleton at the detachable expansion part to conduct the overall expansion test can verify and debug the overall expansion device, correct the expansion device in time, and effectively avoid batch defects in the quality of the finished skeleton expansion, so as to ensure that the overall flatness and skeleton length of the finished skeleton after overall expansion meet the requirements of the skeleton product drawings. At the same time, the sleeve after expansion is designed to be a detachable structure, which realizes the reuse of the simulated skeleton and greatly reduces the cost.

[0021] 1) Design of guide tube

[0022] The target guide tube is a reducer, and its expansion end is a thin-walled end with a wall thickness of 0.5 mm, which cannot meet the design requirements of the threaded connection. Therefore, it is necessary to flip the upper and lower ends of the guide tube 180°, that is, the thick-walled end becomes the upper end of the guide tube, and the thin-walled end becomes the lower end of the guide tube. Then the thick-walled end is designed and processed into M11×1-LH-6H, with a left-handed internal thread of 20 mm in length, which is used to connect the test guide tube sleeve.

[0023] 2) Design of end plug

[0024] Since the thin-walled end of the guide tube becomes the lower end of the guide tube, that is, the inner cavity of the lower end of the guide tube is enlarged, the size of the part pressed into the guide tube in the special lower end plug of the guide tube is also increased accordingly.

[0025] 3) Design of special casing connector

[0026] Design a threaded connector, screw it into the thick-walled end of a special guide tube, and then put on the guide tube sleeve.

[0027] Through the above three structural modifications, the sleeve part of the guide tube assembly can be disassembled, and a new sleeve can be reinstalled and tested again.

[0028] The simulated skeleton formed by the guide tube assembly with this design can also have a corresponding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the guide tube assembly of the detachable expansion joint;

[0030] Figure 2 It is a schematic diagram of a simulated skeleton of a detachable expansion joint;

[0031] Figure 3 It is a schematic diagram of the end plug of the detachable expansion joint;

[0032] In the figure: 1. casing; 2. end grid; 3. guide tube assembly; 4. mixing grid; 5. middle mixing grid; 6. lower tube seat; 7. shoulder screw; 8. casing connector; 9. guide tube; 10. end plug;

[0033] 10-1. Cone; 10-2. Cylindrical part; 10-3. Conical part. DETAILED DESCRIPTION

[0034] The present invention will be further described below through the accompanying drawings and specific implementation methods.

[0035] like Figure 1 As shown, the guide tube assembly 3 includes a sleeve 1 , a sleeve connector 8 , a guide tube 9 and an end plug 10 .

[0036] Both ends of the guide tube 9 are thin-walled ends with a wall thickness of 0.5 mm, and one end is processed with an internal thread section.

[0037] The end plug 10 is pressed into one thin-walled end of the guide tube 9 and fixed by TIG welding. One end of the sleeve connector 8 is processed with an external thread section and screwed into the thread section of the other thin-walled end of the guide tube 9. The other end of the sleeve connector 8 is installed in the sleeve 1.

[0038] The outer diameters of the above-mentioned sleeve connector 8, guide tube 9 and end plug 10 are the same. The sleeve 1 consists of two sections with different diameters but the same wall thickness. The outer surfaces of the two connecting parts are processed into a conical transition, and the inside is processed into a step structure. The above-mentioned sleeve connector 8 achieves axial positioning with the sleeve 1 through the step structure.

[0039] like Figure 2 As shown, the simulation skeleton is composed of 24 of the above-mentioned guide tube assemblies 3, the end grids 2, the mixing grids 4, the middle mixing grids 5 and the lower tube seats 6.

[0040] The 24 guide tube assemblies 3 are inserted into the end grid 2, the mixing grid 4, the middle mixing grid 5 and the lower tube seat 6 according to corresponding positions.

[0041] The end plug 10 is tightened to the lower pipe seat 6 by the shoulder screw 7.

[0042] The guide tube 9 is welded to the above-mentioned various grids by pressure resistance welding.

[0043] like Figure 2 In the example shown, the guide tube assembly 3 sequentially passes through the end grid 2, three groups of mixing grids 4, the middle mixing grid 5, and then sequentially passes through the three mixing grids 4 and the end grid 2, and is finally tightened and positioned on the lower tube seat 6 by the shoulder screw 7.

[0044] like Figure 3 As shown, the end plug 10 includes a truncated cone 10-1 in the middle (whose outer diameter is the same as that of the sleeve connector 8 and the guide tube 9), and c located on both sides of the truncated cone. The end of the cylindrical part is processed with a rounded corner, and the diameter of the conical section changes from large to small. When installed, the cylindrical part is located in the guide tube 9, and the truncated cone is clamped at the end of the guide tube 9.

[0045] The height of the cone section 10-3 is smaller than the height of the frustum 10-1, and the height of the cylindrical section 10-2 is equal to the height of the frustum 10-1.

Claims

1. A simulated skeleton with detachable expansion joints, characterized in that: It is composed of 24 guide tube assemblies (3), two end grids (2), a plurality of mixing grids (4), a plurality of middle mixing grids (5) and a lower tube seat (6); the guide tube assemblies (3) pass through the end grids (2), the mixing grids (4) and the middle mixing grids (5), and the ends of the guide tube assemblies (3) are fixedly connected to the lower tube seat (6); The guide tube assembly (3) comprises a sleeve (1), a sleeve connector (8), a guide tube (9) and an end plug (10); both ends of the guide tube (9) are thin-walled ends, the end plug (10) is fixedly connected to one thin-walled end of the guide tube (9), one end of the sleeve connector (8) is threadedly connected to the other thin-walled end of the guide tube (9), and the other end of the sleeve connector (8) is arranged in the sleeve (1); The end plug (10) comprises a frustum (10-1) in the middle, and a cylindrical portion (10-2) and a conical portion (10-3) located on both sides of the frustum, the cylindrical portion (10-2) being located in the guide tube (9), and the frustum (10-1) being clamped at the end of the guide tube (9); The outer diameter of the truncated cone (10-1) is the same as the outer diameter of the sleeve connecting piece (8) and the guide tube (9); The height of the cone section (10-3) is smaller than the height of the frustum (10-1), and the height of the cylindrical section (10-2) is equal to the height of the frustum (10-1); The end of the cylindrical part (10-2) is processed with a rounded corner, and the diameter of the conical section (10-3) changes from large to small; The sleeve (1) comprises two sections with different diameters but the same wall thickness. The outer surfaces of the connecting parts of the two sections are processed into a conical transition, and the inside is processed into a step structure. The sleeve connector (8) is axially positioned with the sleeve (1) through the step structure.

2. A simulated skeleton with detachable expansion joints as claimed in claim 1, characterized in that: The guide tube (9) is respectively welded and fixed to the end grid (2), the mixing grid (4) and the middle mixing grid (5).

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