Fuel rod pulling device and rod pulling method thereof

Abstract

The invention discloses a fuel rod pulling device and a rod pulling method thereof, and the fuel rod pulling device is used for installing a fuel rod into a positioning grid. The connecting pipe assemblies are used for isolating fuel rods from transverse rigid protrusions of the positioning grillwork, the telescopic driving assemblies are arranged corresponding to the connecting pipe assemblies and used for driving the connecting pipe assemblies to move horizontally, and the rod pulling machine is used for installing the fuel rods into the positioning grillwork. According to the fuel rod pulling device, the fuel rods and the transverse rigid protrusions of the positioning grillwork can be isolated through the arrangement of the connecting pipe assemblies, direct friction and extrusion between the fuel rods and the transverse rigid protrusions are avoided fundamentally, zirconium chips are greatly reduced, meanwhile, scratches on the surfaces of the fuel rods are avoided, and the reliability of safe operation in a fuel assembly reactor is improved. And the telescopic driving assembly can accurately drive the connecting pipe assembly to complete loading and extraction actions, the operation process of existing rod pulling equipment is adapted, large-scale transformation of the existing equipment is not needed, and the practicability is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reactor fuel assembly manufacturing, in particular to a fuel rod drawing device and a fuel rod drawing method thereof. BACKGROUND

[0002] The existing pressurized water reactor fuel assembly rod drawing assembly equipment is generally composed of three parts, including a fuel rod preloading box, an assembly platform and a rod drawing machine. The preloading box is used for accommodating and positioning the fuel rods to be loaded into the framework, the assembly platform is used for positioning and fixing the framework during the rod drawing and tube seat assembly process, and the rod drawing machine is used for grabbing the fuel rods from the preloading box row by row and drawing them into the framework. During the fuel assembly assembly process, when the fuel rods are drawn horizontally into the grid cells, the positioning grid is in contact with the surface of the fuel rod, causing friction and scratching, the rigid transverse protrusions press the fuel rod cladding tube and cause the zirconium material on the surface of the fuel rod to be damaged and fall off, generating zirconium chips and shallow scratches on the surface of the fuel rod. Although most of the zirconium chips can be removed by spraying and cleaning, a small amount of zirconium chips and zirconium chip nodules remain in the fuel assembly, which poses a risk of fuel rod breakage.

[0003] In view of this situation, domestic water lubrication process research has been carried out and put into use, but water lubrication rod drawing can reduce the formation of zirconium chips, but cannot fundamentally eliminate the generation of zirconium chips and shallow scratches on the surface of the fuel rod.

[0004] The present application proposes a new rod drawing scheme from the perspective of reducing the formation of zirconium chips and avoiding scratches on the surface of the fuel rod. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a fuel rod drawing device and a fuel rod drawing method thereof.

[0006] The technical scheme adopted by the present application to solve the technical problem is: a fuel rod drawing device is constructed for installing fuel rods into a positioning grid, which comprises a plurality of connecting pipe assemblies for isolating the fuel rods from the transverse protrusions of the positioning grid, a telescopic drive assembly corresponding to the connecting pipe assemblies and used for driving the connecting pipe assemblies to move horizontally, and a rod drawing machine used for installing the fuel rods into the positioning grid. Each connecting pipe assembly comprises a positioning pipe, a guide end plug detachably connected to one end of the positioning pipe, and a connecting end plug fixedly connected to the other end of the positioning pipe. Each telescopic drive assembly comprises a motor, a gear drivingly connected to the motor, a rack meshing with the gear, a connecting shaft fixedly connected to one end of the rack, a transition piece detachably connected to the connecting shaft, and a claw movably connected to the transition piece, the claw being connected to the connecting end plug in a matched manner.

[0007] In some embodiments, the transition piece is a T-shaped screw, the connecting shaft is provided with a central threaded hole, the T-shaped screw is threadedly connected with the central threaded hole, and the light rod part of the T-shaped screw is connected to the claw.

[0008] In some embodiments, the claw is provided with a positioning groove for mounting the light rod part of the T-shaped screw, the claw can rotate along the axis of the light rod part of the T-shaped screw, and the claw can move along the axial direction of the T-shaped screw.

[0009] In some embodiments, the positioning tube is a semicircular structure, and the radius of the positioning tube is greater than the radius of the cladding of the fuel rod.

[0010] In some embodiments, the edge of the positioning tube is provided with a chamfered part.

[0011] In some embodiments, the wall thickness of the positioning tube is greater than 0.3 mm and not greater than 1 mm.

[0012] In some embodiments, the end of the guide end plug is conical.

[0013] In some embodiments, the fuel rod pulling device further comprises a baffle for preventing the movement of the fuel rod when the positioning tube is pulled out.

[0014] In the present embodiment, a fuel rod pulling method of the fuel rod pulling device is also constructed, which is applied to the fuel rod pulling device, and comprises the following steps: S1, controlling the action of the telescopic driving assembly, rotating the gear driven by the motor, and driving the rack to extend; S2, rotating the claw above the connecting end plug, then moving the claw to the position aligned with the connecting end plug, and rotating the claw below the connecting end plug to realize the connection of the claw and the connecting end plug; S3, pushing out a row of positioning tubes with guide end plugs by the telescopic driving assembly and loading them into the positioning grid, so that the positioning tubes are positioned on the transverse rigid convexes of the positioning grid, and then removing the guide end plugs; S4, controlling the pull rod of the pulling machine to pass through the positioning grid and pull out the fuel rod to a predetermined position; S5, installing the baffle, and then pulling out the positioning tube by the telescopic driving assembly; S6, repeating steps S1 to S5 until all the fuel rods of the fuel assembly are loaded into the positioning grid.

[0015] In some embodiments, during the process of pulling out the fuel rod by the pull rod of the pulling machine, the pulling force of the pulling machine is detected by using a pulling force sensor.

[0016] The fuel rod pulling device has the following beneficial effects: the fuel rod pulling device can isolate the fuel rod from the transverse rigid protrusion of the positioning grid through the setting of the connecting pipe assembly, thus avoiding direct friction and extrusion of the fuel rod and the transverse rigid protrusion from the root, greatly reducing the generation of zirconium chips, avoiding scratches on the surface of the fuel rod, and improving the reliability of the safe operation of the fuel assembly in the reactor. The telescopic driving assembly can accurately drive the connecting pipe assembly to complete the loading and extraction actions, adapt to the operation process of the existing rod pulling equipment, and do not need to make large-scale modification to the existing equipment, and has high practicability. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the present application, the present application will be further described below in conjunction with the drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings: Fig. 1 is a schematic diagram of the three-dimensional structure of the fuel rod pulling device in some embodiments of the present application; Fig. 2 is a schematic diagram of the cooperation of the connecting pipe assembly and the telescopic driving assembly before connection in some embodiments of the present application; Fig. 3 is a schematic diagram of the structure of the positioning pipe installed on the positioning grid in some embodiments of the present application. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the technical solutions of the present application, the present application will be further described below in conjunction with the drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings:

[0019] It should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing", "arranging" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. When an element is referred to as "on" or "below" another element, the element can be "directly" or "indirectly" above another element, or one or more intervening elements can exist. The terms "first", "second", "third" and the like are only for the convenience of describing the technical solutions herein, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features with "first", "second", "third" and the like can be explicitly or implicitly included one or more of the features. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0020] Please refer to Figs. 1 to 3 It is a fuel rod pulling device in some embodiments of the present application, which is used for installing fuel rods 3 into a positioning grid 4, and comprises a plurality of connecting pipe assemblies 1 for isolating the fuel rods 3 from the transverse protrusions 41 of the positioning grid 4, a telescopic drive assembly 2 corresponding to the connecting pipe assembly 1 and used for driving the connecting pipe assembly 1 to move horizontally, and a rod pulling machine used for installing the fuel rods 3 into the positioning grid 4. Each connecting pipe assembly 1 comprises a positioning pipe 11, a guide end plug 12 detachably connected to one end of the positioning pipe 11, and a connecting end plug 13 fixedly connected to the other end of the positioning pipe 11; each telescopic drive assembly 2 comprises a motor, a gear 21 drivingly connected to the motor, a rack 22 engaged with the gear 21, a connecting shaft 23 fixedly connected to one end of the rack 22, a transition piece 24 detachably connected to the connecting shaft 23, and a claw 25 movably connected to the transition piece 24, the claw 25 being connected with the connecting end plug 13.

[0021] Specifically, the number of connecting pipe assemblies 1 and telescopic drive assemblies 2 corresponds one by one, which can be set according to the number of fuel rods 3 to be installed, and can be 17, 15 or other numbers. For example, Fig. 3As shown, the positioning tube 11 can be loaded into the positioning grid 4 before the fuel rod 3 is loaded, directly blocking the transverse rigid protrusions 41 of the fuel rod 3 and the positioning grid 4, avoiding the extrusion, friction and scratching of the fuel rod 3 cladding by the rigid protrusions. The guide end plug 12 is detachably connected with the positioning tube 11 and located at one end of the positioning tube 11. This design not only ensures the guiding effect of the positioning tube 11 when it is loaded into the positioning grid 4, but also can be removed before the fuel rod 3 is loaded, avoiding interference with the movement of the fuel rod 3. The connecting end plug 13 can be fixedly connected with the positioning tube 11 by welding, serving as a connection node of the connecting tube assembly 1 and the telescopic driving assembly 2. The fixed connection mode ensures the stability of the connection during the rod pulling process. The telescopic driving assembly 2 is correspondingly arranged with the connecting tube assembly 1, ensuring that each connecting tube assembly 1 can be independently driven. The structure includes a motor, a gear 21, a rack 22, a connecting shaft 23, a transition piece 24 and a clamping jaw 25. The connection and movement relationship of each component forms a complete transmission chain. At the same time, the design of the telescopic driving assembly 2 converts the rotary motion of the motor into the linear motion of the rack 22 through the meshing of the gear 21 and the rack 22, and then drives the connecting shaft 23 and the subsequent components to move horizontally, realizing the loading and extraction actions of the connecting tube assembly 1. This transmission mode has the characteristics of accurate positioning and stable movement, which meets the high-precision requirements of the fuel rod 3 loading. In addition, the connecting shaft 23 is movably connected with the clamping jaw 25 through the transition piece 24, and the clamping jaw 25 is rotatably connected with the connecting end plug 13, forming a detachable linkage structure of the telescopic driving assembly 2 and the connecting tube assembly 1. This design makes the telescopic driving assembly 2 flexible to adapt to connecting tube assemblies 1 of different specifications, and facilitates the disassembly and maintenance of the components. The telescopic driving assembly 2 drives the connecting tube assembly 1 to move horizontally, accurately limiting the movement direction of the connecting tube assembly 1, ensuring that the connecting tube assembly 1 can be loaded into or extracted from the positioning grid 4 along the horizontal direction, which is consistent with the horizontal operation direction of the fuel rod 3 loading.

[0022] Understandably, the fuel rod pulling device sets the connecting tube assembly 1 and the telescopic driving assembly 2. The connecting tube assembly 1 can isolate the fuel rod 3 from the transverse rigid protrusions 41 of the positioning grid 4, avoiding direct friction and extrusion between the fuel rod 3 and the transverse rigid protrusions 41, greatly reducing the generation of zirconium chips, and avoiding scratches on the surface of the fuel rod 3, thereby improving the reliability of the safe operation of the fuel assembly in the reactor. The telescopic driving assembly 2 can accurately drive the connecting tube assembly 1 to complete the loading and extraction actions, adapt to the operation process of the existing rod pulling equipment, and do not need to make large-scale modifications to the existing equipment, which has strong practicality.

[0023] Preferably, the transition piece 24 is a T-shaped screw, a central threaded hole is formed in the center of the connecting shaft 23, the T-shaped screw is threadedly connected with the central threaded hole, and a light rod part of the T-shaped screw is connected with the clamping jaw 25. The transition piece 24 is arranged as a T-shaped screw, detachable assembly with the connecting shaft 23 is realized through thread connection, the assembly is stable and convenient to disassemble and assemble, meanwhile, the light rod part of the T-shaped screw can provide a mounting and movement carrier for the clamping jaw 25, and the cooperation and connection precision of the clamping jaw 25 and the connecting end plug 13 is ensured. Before the T-shaped screw is assembled into the connecting shaft 23, the clamping jaw 25 needs to be assembled into the light rod part of the T-shaped screw.

[0024] The clamping jaw 25 is provided with a positioning groove 251 for mounting the light rod part of the T-shaped screw, the clamping jaw 25 can rotate along the axis of the light rod part of the T-shaped screw, and the clamping jaw 25 can move along the axial direction of the T-shaped screw. The clamping jaw 25 is provided with the positioning groove 251 and can rotate and move along the light rod part of the T-shaped screw, so that the clamping jaw 25 can be flexibly adjusted in position to butt against the connecting end plug 13, the clamping jaw 25 and the connecting end plug 13 are quickly and accurately connected, the assembly efficiency of the connecting pipe assembly 1 and the telescopic driving assembly 2 is improved, meanwhile, the stability after connection is ensured, and falling off during the rod pulling process is avoided.

[0025] The positioning tube 11 is a semicircular structure, the radius of the positioning tube 11 is greater than the radius of the cladding of the fuel rod 3, which can effectively wrap the fuel rod 3, isolate the fuel rod 3 from the lateral rigid convex 41 of the positioning grid 4, and reserve enough space for the movement of the fuel rod 3 to avoid excessive friction between the fuel rod 3 and the inner wall of the positioning tube 11. In addition, the guide end plug 12 is a semicircular guide end plug, the connecting end plug 13 is a semicircular connecting end plug, and the clamping jaw 25 is a semicircular clamping jaw, which are adapted to the corresponding semicircular structure of the positioning tube 11. In some other embodiments, in addition to the semicircular positioning tube 11, irregular semicircular designs can also be used to isolate the fuel rod 3 and the lateral rigid convex 41 of the positioning grid 4.

[0026] The edge of the positioning tube 11 is provided with a chamfered part, which can eliminate the sharp edge of the positioning tube 11, avoid scratching when the fuel rod 3 contacts the edge of the positioning tube 11, further prevent scratches on the surface of the fuel rod 3, and facilitate the assembly of the positioning tube 11 into the positioning grid 4.

[0027] The wall thickness of the positioning tube 11 is greater than 0.3 mm and not greater than 1 mm, which not only ensures that the positioning tube 11 has sufficient structural strength and can resist external forces during the rod pulling process without deformation, but also avoids increasing the rod pulling force due to excessive wall thickness, and prevents the generation of new zirconium chips due to excessive friction between the thick tube wall and the fuel rod 3 or the positioning grid 4 when the positioning tube 11 is pulled out.

[0028] The end of the guide end plug 12 is tapered, forming a guide structure that can guide during the process of loading the positioning tube 11 into the positioning grid 4, reducing the resistance of loading the positioning tube 11, enabling the positioning tube 11 to enter the grid element of the positioning grid 4 more smoothly, and improving the assembly efficiency.

[0029] The fuel rod pulling device further comprises a baffle for preventing the fuel rod 3 from moving when the positioning tube 11 is pulled out, and the added baffle can block the fuel rod 3 when the positioning tube 11 is pulled out, prevent the fuel rod 3 from deviating from the predetermined position due to the movement of the positioning tube 11, ensure the position accuracy of the fuel rod 3, and avoid problems in subsequent assembly processes caused by the displacement of the fuel rod 3.

[0030] In the embodiment, a fuel rod pulling method of the fuel rod pulling device is also constructed, which is applied to the above-mentioned fuel rod pulling device, and comprises the steps of: S1, controlling the telescopic driving assembly 2 to act, rotating the gear 21 by the motor, and driving the rack 22 to extend; S2, rotating the clamping jaw 25 above the connecting end plug 13, then moving the clamping jaw 25 to the position aligned with the connecting end plug 13, and rotating the clamping jaw 25 below the connecting end plug 13 to realize the connection between the clamping jaw 25 and the connecting end plug 13; S3, pushing out and loading a row of the positioning tube 11 with the guide end plug 12 into the positioning grid 4 by the telescopic driving assembly 2, so that the positioning tube 11 is positioned on the transverse protrusion 41 of the positioning grid 4, and then removing the guide end plug 12; S4, controlling the pulling rod of the pulling machine to pass through the positioning grid 4, and pulling out the fuel rod 3 to the predetermined position; S5, installing the baffle, and then pulling out the positioning tube 11 by the telescopic driving assembly 2; S6, repeating the steps S1 to S5 until all the fuel rods 3 of the fuel assembly are loaded into the positioning grid 4.

[0031] The fuel rod pulling method of the present application is realized based on the above-mentioned pulling device, and the loading of the connecting tube assembly 1, the pulling and loading of the fuel rod 3, and the pulling out of the positioning tube 11 are controlled through standardized steps, the operation process is clear and operable, the quality and efficiency of the pulling and loading of the fuel rod 3 can be effectively guaranteed, and the assembly rhythm of the existing fuel assembly can be adapted, and the method is easy to popularize and apply in production.

[0032] In the process of pulling rod 3 out of the fuel rod 3 by the pull rod machine, the pulling force sensor is used to detect the pulling force of the pull rod machine. The pulling force sensor is used to detect the pulling force during the pulling process, so that the stress condition of the pulling operation can be monitored in real time, and when the pulling force is abnormal, it can be found and handled in time to avoid the fuel rod 3 being damaged or the positioning tube 11 being deformed due to the pulling force being too large, thereby further ensuring the safety and stability of the pulling operation.

[0033] It can be understood that the above embodiments only express the preferred embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application; it should be pointed out that for ordinary skilled in the art, the above technical features can be freely combined without departing from the concept of the present application, and several modifications and improvements can be made, which belong to the protection scope of the present application; therefore, any equivalent transformation and modification within the scope of the claims of the present application shall belong to the scope of the claims of the present application.

Claims

1. A fuel rod pulling device for installing fuel rods (3) into a positioning grid (4), characterized in that, It includes a connecting pipe assembly (1) with multiple transverse rigid protrusions (41) for isolating fuel rods (3) from positioning grids (4), a telescopic drive assembly (2) corresponding to the connecting pipe assembly (1) and used to drive the connecting pipe assembly (1) to move horizontally, and a rod pulling machine for installing fuel rods (3) into positioning grids (4); Each of the connecting tube assemblies (1) includes a positioning tube (11), a guide end plug (12) detachably connected to one end of the positioning tube (11), and a connecting end plug (13) fixedly connected to the other end of the positioning tube (11). Each of the telescopic drive components (2) includes a motor, a gear (21) driven by the motor, a rack (22) meshing with the gear (21), a connecting shaft (23) fixedly connected to one end of the rack (22), a transition piece (24) detachably connected to the connecting shaft (23), and a pawl (25) movably connected to the transition piece (24). The pawl (25) is engaged with the connecting end plug (13).

2. The fuel rod pulling device according to claim 1, characterized in that, The transition piece (24) is a T-shaped screw, and the connecting shaft (23) has a central threaded hole. The T-shaped screw is threadedly connected to the central threaded hole, and the smooth part of the T-shaped screw is connected to the chuck (25).

3. The fuel rod pulling device according to claim 2, characterized in that, The claw (25) is provided with a positioning groove (251) for mounting the smooth part of the T-screw. The claw (25) can rotate along the axis of the smooth part of the T-screw and can move along the axial direction of the T-screw.

4. The fuel rod pulling device according to claim 1, characterized in that, The positioning tube (11) has a semi-circular structure, and the radius of the positioning tube (11) is greater than the radius of the cladding of the fuel rod (3).

5. The fuel rod pulling device according to claim 1, characterized in that, The edge of the positioning tube (11) is chamfered.

6. The fuel rod pulling device according to claim 1, characterized in that, The wall thickness of the positioning tube (11) is greater than 0.3 mm and not greater than 1 mm.

7. The fuel rod pulling device according to claim 1, characterized in that, The end of the guide plug (12) is tapered.

8. The fuel rod pulling device according to claim 1, characterized in that, The fuel rod pulling device also includes a baffle for preventing the fuel rod (3) from moving when the positioning tube (11) is pulled out.

9. A method for pulling a fuel rod in a fuel rod pulling device, applied to the fuel rod pulling device according to any one of claims 1 to 8, characterized in that, Including the following steps: S1. Control the telescopic drive component (2) to move, drive the gear (21) to rotate through the motor, and drive the rack (22) to extend; S2. Rotate the claw (25) above the connecting end plug (13), then move the claw (25) to a position aligned with the connecting end plug (13) and rotate it below the connecting end plug (13) to achieve the connection between the claw (25) and the connecting end plug (13); S3. A row of positioning tubes (11) with guide end plugs (12) is pushed out and installed into the positioning grid (4) by telescopic drive assembly (2), so that the positioning tubes (11) are positioned on the transverse rigid protrusion (41) of the positioning grid (4), and then the guide end plugs (12) are removed. S4. Control the rod puller to pass through the positioning grid (4) and pull the fuel rod (3) to the predetermined position; S5. Install the baffle, and then pull out the positioning tube (11) through the telescopic drive assembly (2); S6. Repeat steps S1 to S5 until all fuel rods (3) of the fuel assembly are installed in the positioning grid (4).

10. The method for pulling the fuel rod of the fuel rod pulling device according to claim 9, characterized in that, During the process of the rod pulling machine pulling out the fuel rod (3), the pulling force of the rod pulling machine is detected by the pulling force sensor.

Images