An auxiliary guiding tool for a nuclear power neutron source assembly and its usage method

Abstract

The present invention discloses an auxiliary guiding tool for a nuclear power neutron source assembly and its usage method, which includes a long rod, a movable tube, a chuck and an adjusting structure. The chuck includes a mounting seat. The lower end of the long rod is inserted into the movable tube. A chuck block is mounted on the mounting seat, and a clamping groove is provided on the chuck block. The adjusting structure includes a handwheel, a mounting box and a threaded connecting rod. The handwheel is connected with a rotating shaft, and the rotating shaft is connected with a bevel gear I. The bevel gear I is mounted in the mounting box, and the mounting box is fixed on one side of the upper end of the long rod. A bevel gear II is provided inside the mounting box. The threaded connecting rod is arranged parallel to the long rod. The upper end of the threaded connecting rod is rotatably inserted into the mounting box and fixedly connected with the bevel gear II. The lower end of the threaded connecting rod is connected with a nut, and the nut is fixedly connected with the upper end of the movable tube through a connecting plate. The neutron source assembly installation auxiliary guiding tool of the present invention can effectively assist in the installation of the neutron source assembly, is simple to operate, and reduces the damage to the rod bundle of the neutron source assembly.

Description

Technical Field

[0001] The present invention belongs to the technical field of auxiliary tools, and particularly relates to an auxiliary guiding tool for a nuclear power neutron source assembly and a using method thereof. Background Art

[0002] In a nuclear power plant, there are 24 guiding tubes in a fuel assembly for inserting fuel-related components (types of fuel-related components include: control rod assembly, primary neutron source assembly, secondary neutron source assembly, burnable poison assembly, and flow restrictor plug assembly). During each unit refueling outage, after all fuel assemblies are unloaded from the core to the spent fuel pool, due to different burnup requirements of the fuel assemblies at the core positions, the loading positions of the fuel assemblies in the core are not exactly the same each time. Thus, the relevant components inserted into the fuel assemblies need to be adjusted according to the positions of the fuel assemblies in the core. According to the relevant component switching and movement plan for the nuclear power plant outage, in the spent fuel pool in the fuel building, the relevant components in the fuel assemblies are switched using special grabs for the relevant components. Only after the relevant component switching work is completed can the refueling work be carried out. This is an important task in the fuel operation of a nuclear power plant.

[0003] The secondary neutron source assembly, such as Figure 2 shown, there are 2 groups of secondary neutron source assemblies in a single unit. Each group of assemblies has 4 secondary neutron source rods (long single rods: length about 3846 mm, diameter about ¢9.7 mm, wall thickness about 0.43 mm), 20 flow restrictor plug rods (short single rods: length about 201 mm, diameter about ¢9.7 mm, solid), as Figure 2 described. Its function is to increase the neutron flux level during refueling and the subcritical state of the core, avoid the monitoring blind area of nuclear instrumentation, and ensure the critical safety of the reactor. Since there are only four rods in the secondary neutron source assembly and there are no spare parts for a single unit, once a neutron source rod is damaged, it will affect the subsequent nuclear power plant outage work. Due to the extensibility of the fuel assembly, during the operation of the unit at power, the fuel assembly will deform, which is an inevitable and allowable phenomenon. The upper end of the secondary neutron source assembly is a hollow tube, and the lower end is partially filled with antimony-beryllium pellets, with the characteristics of a slender tube. After being irradiated at high temperature in the reactor, it is prone to deformation; and once stressed, it is extremely prone to bending. In domestic nuclear power plants, there has been an event where during the neutron source switching, the neutron source assembly did not enter the fuel assembly, resulting in the bending of the neutron source rod.

[0004] For the handling of deformed neutron source switching, currently, the main methods for handling the situation where the deformed neutron source assembly cannot be lowered in place at Fuqing Nuclear Power Plant are as follows: rotating the secondary neutron source assembly by 180°, inserting the fuel assembly, and using a long rod to touch the neutron source assembly to lower it. Both methods have drawbacks. When rotating the neutron source, the operator cannot observe the grab load display, and an additional operator is required to observe the load display, which poses a risk of communication failure. When using a long rod to touch the neutron source, since the end of the long rod is relatively hard and the long rod extends nearly 10 m underwater, the operator cannot control the force, which may cause damage to the neutron source rod. Therefore, a special tool that can effectively assist in guiding the neutron source is needed. Summary of the Invention

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a nuclear power neutron source assembly auxiliary guiding tool, including a long rod, a movable tube, a chuck, and an adjusting structure. The chuck includes a mounting seat fixedly connected to one end of the movable tube. The lower end of the long rod is movably inserted into the movable tube from the other end. A chuck block is mounted on the mounting seat, and a clamping groove is provided on the chuck block. The adjusting structure includes a handwheel, a mounting box, and a threaded connecting rod. The handwheel is connected to a rotating shaft, and the rotating shaft is rotatably inserted into the interior of the mounting box through a bearing and then connected to a bevel gear I. The bevel gear I is mounted inside the mounting box. The mounting box is fixed to one side of the upper end of the long rod. A bevel gear II meshing with the bevel gear I is provided inside the mounting box. The threaded connecting rod is arranged parallel to the long rod. The upper end of the threaded connecting rod is rotatably inserted into the mounting box through a bearing and fixedly connected to the bevel gear II. The lower end of the threaded connecting rod is connected to a nut, and the nut is fixedly connected to the upper end of the movable tube through a connecting plate.

[0006] As a preference of the above technical solution, a screw rod is fixedly connected to the upper end of the chuck block, and a threaded hole for the screw rod to be screwed into is provided on the mounting seat.

[0007] As a preference of the above technical solution, a number of buffer pads are detachably mounted on the inner wall of the clamping groove.

[0008] As a preference of the above technical solution, a number of bearing seats are fixedly connected to the middle of the long rod, and the threaded connecting rod passes through the bearing seats in sequence.

[0009] As a preference of the above technical solution, a limiting plate is fixedly connected to the lower end of the threaded connecting rod.

[0010] As a preference of the above technical solution, a number of sliding grooves are provided on the inner wall of the movable tube, and a number of sliding blocks are provided at the lower end of the long rod. The sliding blocks are slidably inserted into the sliding grooves.

[0011] As a preference of the above technical solution, an opening is provided on the mounting box, and a box cover is covered at the opening.

[0012] The usage method of the auxiliary guiding tool for the nuclear power neutron source assembly includes the following steps: Use a crane to lift the neutron source assembly and gradually lower it into the pool, so that the long single rod on the neutron source assembly is close to the installation hole in the pool. Hold the long rod by hand and extend the chuck into the pool. Use the clamping groove to clamp the long single rod. Control the angle of the long rod, turn the handwheel to adjust the height of the chuck, and the neutron source assembly descends by a certain height accordingly. After aligning each long single rod with the corresponding installation hole in sequence, the neutron source assembly continues to descend to complete the installation of the neutron source assembly.

[0013] The beneficial effects of the present invention are as follows: The auxiliary guiding tool for the nuclear power neutron source assembly of the present invention can effectively assist in the installation of the neutron source assembly, is easy to operate, and reduces damage to the rod bundle of the neutron source assembly. Brief Description of the Drawings

[0014] Figure 1 is the structural schematic diagram of the present invention;

[0015] Figure 2 is the structural schematic diagram of the neutron source assembly. Detailed Embodiments

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0017] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0018] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] Such as Figure 1As shown in the figure, a nuclear power neutron source assembly auxiliary guiding tool includes a long rod 1, a movable tube 2, a chuck and an adjusting structure. The chuck includes a mounting seat 3 fixedly connected to one end of the movable tube 2. The lower end of the long rod 1 is movably inserted into the movable tube 2 from the other end of the movable tube 2. A chuck block 4 is mounted on the mounting seat 3, and a clamping groove 5 is provided on the chuck block 4. The adjusting structure includes a handwheel 6, a mounting box 7, and a threaded connecting rod 8. The handwheel 6 is connected to a rotating shaft 9, and the rotating shaft 9 is rotatably extended into the interior of the mounting box 7 through a bearing and then connected to a bevel gear I 10. The bevel gear I 10 is mounted in the mounting box 7. The mounting box 7 is fixed to one side of the upper end of the long rod 1. A bevel gear II 11 meshing with the bevel gear I 10 is provided inside the mounting box 7. The threaded connecting rod 8 is arranged parallel to the long rod 1. The upper end of the threaded connecting rod 8 is rotatably extended into the mounting box 7 through a bearing and fixedly connected to the bevel gear II 11. The lower end of the threaded connecting rod 8 is connected to a nut 12, and the nut 12 is fixedly connected to the upper end of the movable tube 2 through a connecting plate 13. After lifting the neutron source assembly with a crane and lowering it into the pool, when the neutron source assembly descends to a certain height and stops, hold the long rod 1 and insert the chuck into the pool. Use the chuck to clamp the lower end of the long single rod in the inclined direction. By adjusting the angle of the long rod 1 and rotating the handwheel 6, guide it to align with the installation hole below and insert it into the installation hole. The distance of the chuck can be finely adjusted through the handwheel 6 to avoid damaging the neutron source assembly due to excessive force. The process of the nuclear power neutron source assembly auxiliary guiding tool assisting in the installation of the neutron source assembly is shown in Figure 2 the figure shown.

[0020] Furthermore, a screw rod 14 is fixedly connected to the upper end of the chuck block 4, and a threaded hole 15 for the screw rod 14 to be screwed into is provided on the mounting seat 3. In this way, the chuck block 4 is detachably mounted on the mounting seat 3, and the angle of the chuck block 4 is adjustable.

[0021] Furthermore, a number of buffer pads 16 are detachably mounted on the inner wall of the clamping groove 5. The buffer pads 16 can be made of materials with certain elasticity such as rubber and plastic. The buffer pads 16 prevent the clamping groove 5 from wearing and damaging the neutron source assembly. The buffer pads 16 are detachably mounted on the inner wall of the clamping groove 5 through screws or the like, so that the buffer pads 16 can be replaced regularly to prevent the buffer pads 16 from aging and falling off into the pool to form foreign objects during the use process.

[0022] Furthermore, a number of bearing seats 17 are fixedly connected to the middle of the long rod 1, and the threaded connecting rod 8 passes through the bearing seats 17 in sequence. The bearing seats 17 make the rotation process of the threaded connecting rod 8 stable and solve the problem that it is easy to shake during rotation due to its excessive length.

[0023] Furthermore, a limiting plate 18 is fixedly connected to the lower end of the threaded connecting rod 8. The limiting plate 18 limits the lowest position of the nut 12 moving on the threaded connecting rod 8 to prevent the nut 12 from falling off the threaded connecting rod 8.

[0024] Furthermore, a plurality of sliding grooves 19 are provided on the inner wall of the movable tube 2, and a plurality of sliding blocks 20 are provided at the lower end of the long rod 1. The sliding blocks 20 can slidably extend into the sliding grooves 19. The cooperation between the sliding blocks 20 and the sliding grooves 19 makes the movement process of the movable tube 2 in the long rod 1 smoother, ensuring that the movable tube 2 only moves around the axis direction of the long rod 1.

[0025] Furthermore, an opening 21 is provided on the mounting box 7, and a box cover 22 is covered at the opening 21. Opening the box cover 22 allows adding butter or the like to the bevel gear I 10 and the bevel gear II 11 to improve lubricity. In this way, rotating the hand wheel 6 can effectively drive the threaded link 8 to rotate through the cooperation of the bevel gear I 10 and the bevel gear II 11, ensuring the rotation accuracy of the hand wheel 6 to control the threaded link 8.

[0026] In order to reduce the overall weight, the long rod 1 can be hollow.

[0027] It is worth mentioning that the technical features such as the neutron source assembly involved in this invention patent application should be regarded as the prior art. The specific structures, working principles, and possible control methods and spatial arrangement methods involved in these technical features can be selected conventionally in this field and should not be regarded as the inventive points of this invention patent. This invention patent will not be further specifically elaborated.

[0028] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in this technical field based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. An auxiliary guiding tool for a nuclear power neutron source assembly, characterized in that It includes a long rod, a movable tube, a chuck and an adjustment structure. The chuck includes a mounting seat fixedly connected to one end of the movable tube. The lower end of the long rod is movably inserted into the movable tube from the other end of the movable tube. A chuck block is mounted on the mounting seat, and a clamping groove is provided on the chuck block. The adjustment structure includes a handwheel, a mounting box and a threaded connecting rod. The handwheel is connected with a rotating shaft, and the rotating shaft is rotatably extended into the interior of the mounting box through a bearing and then connected with a bevel gear I. The bevel gear I is mounted in the mounting box. The mounting box is fixed on one side of the upper end of the long rod. A bevel gear II meshing with the bevel gear I is provided inside the mounting box. The threaded connecting rod is arranged parallel to the long rod. The upper end of the threaded connecting rod is rotatably extended into the mounting box through a bearing and fixedly connected with the bevel gear II. The lower end of the threaded connecting rod is connected with a nut, and the nut is fixedly connected with the upper end of the movable tube through a connecting plate. The upper end of the chuck block is fixedly connected with a screw rod, and a threaded hole for the screw rod to be screwed into is provided on the mounting seat. A plurality of bearing seats are fixedly connected to the middle of the long rod, and the threaded connecting rod sequentially passes through the bearing seats.

2. The auxiliary guiding tool for the nuclear power neutron source assembly according to claim 1, wherein, A plurality of buffer pads are detachably mounted on the inner wall of the clamping groove.

3. The auxiliary guiding tool for the nuclear power neutron source assembly according to claim 1, wherein A limiting plate is fixedly connected to the lower end of the threaded connecting rod.

4. The auxiliary guiding tool for the nuclear power neutron source assembly according to claim 1, wherein A plurality of sliding grooves are provided on the inner wall of the movable tube, and a plurality of sliding blocks are provided at the lower end of the long rod. The sliding blocks are slidably extended into the sliding grooves.

5. The auxiliary guiding tool for the nuclear power neutron source assembly according to claim 1, wherein An opening is provided on the mounting box, and a box cover is covered at the opening.

6. The method for using the auxiliary guiding tool for the nuclear power neutron source assembly according to any one of claims 1-5, characterized in that, It includes the following steps: Use a crane to lift the neutron source assembly and gradually lower it into the water tank, so that the long single rod on the neutron source assembly is close to the mounting hole in the water tank. Hold the long rod by hand and make the chuck extend into the water tank. Clamp the long single rod with the clamping groove, control the angle of the long rod, shake the handwheel to adjust the height of the chuck, the neutron source assembly cooperates to descend a certain height. After aligning each long single rod with the corresponding mounting hole in turn, the neutron source assembly continues to descend to complete the installation of the neutron source assembly.

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