A nuclear fuel assembly gripper for a pressurized water reactor in a nuclear power plant

Abstract

The present invention relates to the technical field of pressurized water reactors and spent fuel post-processing in nuclear power plants, and in particular to a gripper for nuclear fuel assemblies in pressurized water reactors in nuclear power plants. It comprises a vertically arranged sleeve, the bottom of which is connected to a positioning plate, a connecting rod is arranged inside the sleeve, the sleeve is coaxial with the connecting rod, the top of the connecting rod passes through the sleeve and is upwardly connected to a rotating handle, the bottom of the connecting rod passes through the sleeve and the positioning plate to connect a gripping plate, the connecting rod is rotatably connected to the positioning plate, and after the gripping plate rotates a certain angle, the gripping plate can clamp the inner wall of the nuclear fuel assembly. The present invention avoids the gripping defects of existing grippers, and on-site operators can directly observe the entire process of gripping and releasing the assembly end on a crane, without blind spots; the structural design is simple and compact, and maintenance and repair operations are few, which is sufficient to realize the frequent operation of receiving and storing pressurized water reactor nuclear fuel assemblies.

Description

Technical Field

[0001] The invention relates to the technical field of pressurized water reactors and spent fuel post-processing of nuclear power plants, in particular to a nuclear fuel assembly gripper for pressurized water reactors of nuclear power plants. Background Art

[0002] A nuclear fuel assembly refers to a group of fuel elements assembled together, consisting of several fuel elements, upper tube seats, lower tube seats, control rod guide tubes, and spacer grids. It does not need to be disassembled during reactor loading and unloading. A spent fuel reprocessing plant needs to use a nuclear fuel assembly gripper during the spent fuel receiving and storage operations. This tool is used to grab nuclear fuel assemblies and complete the lifting, transportation, and storage operations of nuclear fuel assemblies.

[0003] Most existing nuclear fuel assembly grippers use positioning pins and mechanical grippers to grab nuclear fuel assemblies. Operators need to control the handle at the end of the nuclear fuel assembly gripper and observe the operation vertically downward. When the operator of the nuclear fuel assembly gripper controls the handle at the end of the nuclear fuel assembly gripper, the front end of the gripper completely blocks the positioning pin hole, the compression spring, and the inner wall of the end of the assembly. This leads to safety hazards such as the positioning pin deviating and getting stuck, the gripper getting stuck on the spring, the positioning position being difficult to find, and the gripper positioning status being unable to be observed during the grasping process. In addition, the gripper has many parts. When grabbing nuclear fuel assemblies in a pressurized water reactor of a nuclear power plant, it will be difficult to repair the gripper once it fails underwater, which requires the gripper to have higher structural stability.

[0004] Therefore, it is necessary to provide a nuclear fuel assembly gripper for a pressurized water reactor of a nuclear power plant which is easy to operate and can reduce operation risks. Summary of the invention

[0005] The object of the present invention is to provide a gripper for a nuclear fuel assembly of a pressurized water reactor of a nuclear power station, which has high structural stability and can accurately and conveniently grip the nuclear fuel assembly.

[0006] The present invention provides a gripper for nuclear fuel assemblies of a pressurized water reactor in a nuclear power plant, comprising a vertically arranged sleeve, the bottom of the sleeve being connected to a positioning plate, a connecting rod being arranged inside the sleeve, the sleeve being coaxial with the connecting rod, the top of the connecting rod passing through the sleeve and being upwardly connected to a rotating handle, the bottom of the connecting rod passing through the sleeve and the positioning plate being connected to a gripping plate, the connecting rod being rotatably connected to the positioning plate, and the gripping plate being able to clamp the inner wall of the nuclear fuel assembly after the gripping plate is rotated to a certain angle.

[0007] Preferably, the connecting rod is connected to the rotating handle via a handle ring seat, the lower portion of the handle ring seat is rotatably connected to the sleeve, the upper portion of the handle ring seat is located above the sleeve, and the upper portion of the handle ring seat is connected to the rotating handle.

[0008] Preferably, a fixing platform is provided on the outside of the top end of the sleeve corresponding to the handle ring seat, a positioning hole is provided on the fixing platform along the radial direction of the sleeve, two limiting holes are provided on the handle ring seat corresponding to the height of the positioning hole, and a positioning pin is provided in the positioning hole.

[0009] Preferably, the central angle between adjacent limiting holes is 45°.

[0010] Preferably, the gripping plate is a rounded square, and after the gripping plate is rotated, the four corners of the gripping plate can abut against the middle positions of the four inner walls of the nuclear fuel assembly.

[0011] Preferably, the upper portion of the connecting rod is connected to a lifting ring via a connecting piece, and the lifting ring is located above the sleeve.

[0012] Preferably, the connecting member includes a horizontal rod, both sides of the upper part of the connecting rod are connected to horizontal rods, the horizontal rods pass through the sleeve to connect to the fixed rods outwardly, the fixed rods extend upward and are connected to the lifting rings, and the sleeve is provided with a sliding groove corresponding to the horizontal rod, and the sliding groove is arranged along the circumference of the sleeve.

[0013] Preferably, a sleeve is provided between the connecting rod and the positioning plate, and the connecting rod and the positioning plate are both rotatably connected to the sleeve.

[0014] Preferably, a water inlet hole is provided at the lower portion of the sleeve, and an air outlet hole is provided at the upper portion of the sleeve.

[0015] Preferably, both sides of the upper portion of the sleeve are connected to support frames, and the support frames are arranged horizontally.

[0016] Beneficial effects:

[0017] The present invention avoids the grasping defects of the existing grasping tools. On-site operators can directly observe the entire process of grasping and releasing the assembly end on the crane without blind spots. The structural design is simple and compact, and the maintenance and repair operations are few, which is sufficient to realize the frequent operations of receiving and storing pressurized water reactor nuclear fuel assemblies. By setting the grasping plate and the positioning plate and changing the angle relationship between the two, the positioning and grasping of the nuclear fuel assembly can be realized simply and quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a front cross-sectional view of the present invention;

[0020] Figure 2 It is a left-side structural schematic diagram of the present invention;

[0021] Figure 3 It is a cross-sectional view of the horizontal plane where the positioning pin of the present invention is located;

[0022] Figure 4 It is a cross-sectional view of the positioning state of the end of the nuclear fuel assembly of the present invention;

[0023] Figure 5 It is a cross-sectional view of the present invention and the nuclear fuel assembly end grabbing state;

[0024] Figure 6 It is a top view schematic diagram of the present invention and the nuclear fuel assembly end grabbing state.

[0025] Description of reference numerals:

[0026] 1- casing, 2- connecting rod, 3- positioning plate, 4- grab plate, 5- sleeve, 6- support frame, 7- horizontal rod, 8- fixed rod, 9- lifting ring, 10- handle ring seat, 11- fixed platform, 12- positioning pin, 13- rotating handle, 14- slide groove, 15- positioning hole, 16- limiting hole, 17- groove, 18- nuclear fuel assembly end, 19- water inlet, 20- air outlet. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0029] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. 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.

[0030] Example 1

[0031] like Figure 1-6 As shown, a gripper for nuclear fuel assemblies of a pressurized water reactor in a nuclear power plant comprises a vertically arranged casing 1, the bottom of which is connected to a positioning plate 3, the positioning plate 3 is adapted to the size and shape of a groove 17 of an end head 18 of the nuclear fuel assembly, and is convenient for engagement and positioning, and at the same time, the size of the positioning plate 3 is smaller than the size of the outer wall of the end head 18 of the nuclear fuel assembly, when the staff operates, the four-side structure of the end head can be fully seen from above the crane, and there is no blind spot between the nuclear fuel assembly and the gripper during the grasping operation, which is convenient for observation.

[0032] A connecting rod 2 is provided inside the sleeve 1. The sleeve 1 and the connecting rod 2 are coaxial. The top of the connecting rod 2 passes through the sleeve 1 and is connected to the rotating handle 13 upward through the handle ring seat 10. The lower part of the handle ring seat 10 is rotatably connected to the inner wall of the sleeve 1. The upper part of the handle ring seat 10 is located above the sleeve 1, and the side wall of the upper part of the handle ring seat 10 is connected to the rotating handle 13. A fixing platform 11 is provided on the top of the sleeve 1 corresponding to the handle ring seat 10. A positioning hole 15 is provided on the fixing platform 11 along the radial direction of the sleeve 1. Two limiting holes 16 are provided on the handle ring seat 10 corresponding to the height of the positioning hole 15. A positioning pin 12 is inserted into the positioning hole 15. The positioning pin 12 can be inserted into the limiting hole 16 through the positioning hole 15, thereby limiting the relative rotation between the sleeve 1 and the connecting rod 2. The limiting hole 16 and the positioning hole 15 are both arranged along the radial direction of the sleeve 1, and the central angle between adjacent limiting holes 16 is 45°. A marking line can be provided on the top of the handle ring seat 10 corresponding to the axis of the limiting hole 16 to facilitate the staff to observe the rotation angle.

[0033] The lengths of the casing 1 and the connecting rod 2 are both greater than 9 meters, which can adapt to the depth of the pressurized water reactor where the spent fuel assembly is located and has a wider application range.

[0034] The upper part of the connecting rod 2 is connected to the lifting ring 9 through a connecting piece, and the lifting ring 9 is located above the sleeve 1 to facilitate the overall movement of the gripper. The connecting piece is an integrated structure, including a horizontal rod 7. Both sides of the upper part of the connecting rod 2 are connected to the horizontal rod 7. The connection point of the horizontal rod 7 is located below the handle ring seat 10. The weight of the sleeve 1 can be carried by the horizontal rod 7. The horizontal rod 7 passes through the sleeve 1 and is connected to the fixed rod 8 outward. The fixed rod 8 extends upward and connects to the lifting ring 9. A slide groove 14 is opened on the sleeve 1 corresponding to the horizontal rod 7. The slide groove 14 is arranged along the circumference of the sleeve 1, and the horizontal rod 7 can move along the slide groove 14.

[0035] The bottom of the connecting rod 2 passes through the sleeve 1, and the positioning plate 3 is connected to the grab plate 4. The connecting rod 2 is rotatably connected to the positioning plate 3. A sleeve 5 is provided between the connecting rod 2 and the positioning plate 3. The connecting rod 2 and the positioning plate 3 are both rotatably connected to the sleeve 5. It is easy to contain fine impurity particles underwater. The sleeve 5 can effectively reduce the probability of the positioning plate 3 and the connecting rod 2 being stuck, and ensure the free rotation between the connecting rod 2 and the positioning plate 3. The sleeve 5 can be made of a copper sleeve, which has high hardness, excellent wear resistance, and is not easy to be stuck.

[0036] A circle of slots is also provided at the bottom of the recess 17 of the end 18 of the nuclear fuel assembly. The gripping plate 4 is a rounded square, slightly smaller than the size of the positioning plate 3, and does not obstruct the line of sight. After the gripping plate 4 is rotated 45°, the four corners of the gripping plate 4 can abut against the middle position of the four inner walls of the slot of the nuclear fuel assembly. The thickness of the gripping plate 4 is less than the height of the slot, which is convenient for rotation. Rotating the rotating handle 13 can drive the connecting rod 2 and the gripping plate 4 to rotate, so that the gripping plate 4 is clamped inside the nuclear fuel assembly, which is convenient for grabbing the nuclear fuel assembly.

[0037] A water inlet 19 is provided at the lower part of the sleeve 1, and an air outlet 20 is provided at the upper part of the sleeve 1. The cavity between the sleeve 1 and the connecting rod 2 is connected to the outside through the water inlet and air outlet to ensure that the pressure in the cavity is consistent with the outside.

[0038] The upper two sides of the casing 1 are connected to the support frame 6, and the support frame 6 is arranged horizontally. The use site is provided with a hanging rack, and the hanging rack includes two sets of parallel racks. When the gripper is placed, the support frame 6 is placed on the rack, which is convenient for storage and has reliable safety performance.

[0039] Working principle:

[0040] The crane lifts the gripper as a whole through the lifting ring 9 until the positioning plate 3 is aligned with the inner groove 17 of the end 18 of the nuclear fuel assembly, and then puts the gripper down as a whole; the positioning pin 12 is pulled out, and the rotating handle 13 is rotated 45 degrees to drive the gripper plate 4 to rotate. The four corners of the gripper plate 4 can abut against the middle position of the inner wall of the four sides of the nuclear fuel assembly slot, and the positioning pin 12 is reinserted to prevent the gripper plate 4 from rotating during the movement of the gripper, thereby ensuring stable gripping;

[0041] The gripper is hoisted as a whole by the hoisting ring 9, and the nuclear fuel assembly is hoisted out of the spent fuel transport container and transferred to the spent fuel storage grid, or when the nuclear fuel assembly needs to be measured for burnup, the nuclear fuel assembly is transferred to the burnup measurement device, or when the spent fuel parts need to be sent for shearing, the nuclear fuel assembly is transferred from the spent fuel storage grid to the assembly transport trolley;

[0042] After transporting to the designated location, loosen the lifting ring, pull out the positioning pin 12 from the limiting hole 16, turn the rotating handle 13, and insert the positioning pin 12 into another limiting hole 16. At this time, the gripping plate 4 is released from the gripping state, and the gripper is lifted as a whole through the lifting ring 9, and the support frame 6 is placed on the storage rack for storage.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nuclear fuel assembly gripper for a pressurized water reactor in a nuclear power plant, characterized in that: It comprises a vertically arranged sleeve, the bottom of the sleeve is connected to the positioning plate, a connecting rod is arranged inside the sleeve, the sleeve is coaxial with the connecting rod, the top of the connecting rod passes through the sleeve and is upwardly connected to a rotating handle, the connecting rod is connected to the rotating handle through a handle ring seat, the lower part of the handle ring seat is rotatably connected to the sleeve, the upper part of the handle ring seat is located above the sleeve, the upper part of the handle ring seat is connected to the rotating handle, a fixing platform is arranged outside the top end of the sleeve corresponding to the handle ring seat, a positioning hole is arranged on the fixing platform, two limiting holes are arranged on the handle ring seat corresponding to the height of the positioning hole, the central angle between adjacent limiting holes is 45°, the positioning hole and the limiting hole are arranged along the radial direction of the sleeve, and a positioning pin is arranged in the positioning hole; The bottom of the connecting rod passes through the sleeve and the positioning plate is connected to the grab plate. The connecting rod is rotatably connected to the positioning plate. The grab plate is a rounded square. After the grab plate is rotated by a certain angle, the four corners of the grab plate can resist the middle position of the four inner walls of the nuclear fuel assembly.

2. The nuclear fuel assembly gripper for a pressurized water reactor of a nuclear power plant according to claim 1, characterized in that: The upper part of the connecting rod is connected to a lifting ring through a connecting piece, and the lifting ring is located above the sleeve.

3. The nuclear fuel assembly gripper for a pressurized water reactor of a nuclear power plant according to claim 2, characterized in that: The connecting member includes a horizontal rod, both sides of the upper part of the connecting rod are connected to horizontal rods, the horizontal rods pass through the sleeve to connect to the fixed rods outwardly, the fixed rods extend upward and connect to the lifting rings, and the sleeve is provided with a sliding groove corresponding to the horizontal rod, and the sliding groove is arranged along the circumference of the sleeve.

4. The nuclear fuel assembly gripper for a pressurized water reactor of a nuclear power plant according to claim 1, characterized in that: A sleeve is provided between the connecting rod and the positioning plate, and both the connecting rod and the positioning plate are rotatably connected to the sleeve.

5. The nuclear fuel assembly gripper for a pressurized water reactor of a nuclear power plant according to claim 1, characterized in that: A water inlet hole is provided at the lower part of the sleeve, and an air outlet hole is provided at the upper part of the sleeve.

6. The nuclear fuel assembly gripper for a pressurized water reactor of a nuclear power plant according to claim 1, characterized in that: Both sides of the upper part of the sleeve are connected to support frames, and the support frames are arranged horizontally.

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