Underwater crawling device for nuclear reactor

Abstract

An underwater crawling device for a nuclear reactor comprises: a drive control mechanism; the crawling mechanism is connected with the driving control mechanism, the crawling mechanism comprises a machine body and a plurality of crawling legs, each crawling leg comprises a translation component and a lifting component, the translation component is connected with the machine body, the lifting component is connected with the translation component, and the machine body is connected with the machine body. The driving control mechanism controls the translation part and the lifting part to move in sequence according to a set sequence; the plurality of crawling legs are matched with one another to drive the machine body to crawl and move to a set position; wherein the lifting component is provided with a positioning guide pin corresponding to a flow hole of a lower grid plate of a reactor core in a reactor pressure vessel, and the lifting component is inserted into the flow hole through the positioning guide pin to realize crawling movement; a machine body guide pin matched with the flow hole is arranged on the bottom face of the machine body, and the machine body guide pin is inserted into the flow hole to achieve positioning and bear horizontal component force.

Description

Technical Field

[0001] This utility model relates to nuclear power plant operation and maintenance technology, and in particular to an underwater crawling device for nuclear reactors. Background Technology

[0002] Nuclear power plants typically undergo refueling overhauls every 18 months to ensure equipment performance and safety. Maintenance of the pressure vessel is particularly crucial. During refueling overhauls, the reactor pool is filled with boric acid solution, and the pressure vessel is located at the bottom of the pool. The height difference between the lower core grid plate inside the pressure vessel and the pool shore can reach over 20 meters. Maintenance work on the pressure vessel requires workers to manually operate tools using long poles or wire ropes (over 20 meters long) while standing on a human bridge. Tasks include installing fuel assembly guides, retrieving foreign objects, and repairing fuel assembly locating pins. The following problems arise when workers manually operate tools located underwater on the lower core grid plate while standing on the human bridge using long poles or wire ropes:

[0003] 1) Visibility is poor in deep water environments. The relevant tools and equipment are operated at a depth of more than 20 meters underwater. The operator's vision is affected by water surface fluctuations and water disturbances, making it difficult to observe and determine the location of the tools and equipment.

[0004] 2) The tools are difficult to operate, resulting in high radiation doses for personnel. Current maintenance operations require the use of long poles or steel cables exceeding 20 meters in length. These tools are cumbersome and difficult to control precisely, demanding extremely high skill levels from the operators. For example, during the installation of fuel assembly guiding tools, multiple operators need to coordinate the adjustment of the steel cable, which is time-consuming, labor-intensive, and prone to errors due to operator fatigue. The prolonged work on the human bridge by multiple personnel leads to high collective radiation doses.

[0005] 3) High error rate in tooling positioning: Operators struggle to locate the designated flow orifice among the hundreds of flow orifices on the lower core grid. The tooling is positioned and installed by observing its relative position to the flow orifices on the lower core grid, making positioning errors highly likely.

[0006] 4) Risk of fuel assembly damage: Due to repeated trial and error operations during the positioning and installation process, the risk of fuel assembly damage is greatly increased. Utility Model Content

[0007] The technical problem to be solved by this utility model is to provide an underwater crawling device for nuclear reactors, addressing the above-mentioned deficiencies of the prior art.

[0008] To achieve the above objectives, this utility model provides an underwater crawling device for nuclear reactors, comprising:

[0009] Drive control mechanism; and

[0010] A crawling mechanism is connected to the drive control mechanism. The crawling mechanism includes a body and multiple crawling legs. Each crawling leg includes a translation component and a lifting component. The translation component is connected to the body, and the lifting component is connected to the translation component. The drive control mechanism controls the translation component and the lifting component to move sequentially in a set order. The multiple crawling legs cooperate with each other to drive the body to crawl and move to a set position.

[0011] The lifting component is provided with a positioning guide pin corresponding to the flow hole of the core lower grid plate in the reactor pressure vessel, and the crawling movement is achieved by inserting the positioning guide pin into the flow hole; the bottom surface of the body is provided with a body guide pin adapted to the flow hole, and the positioning is achieved by inserting the body guide pin into the flow hole.

[0012] The aforementioned underwater crawling device for nuclear reactors includes a body that is an L-shaped structure adapted to fuel assemblies, with crawling legs provided on the end face and outer side of the L-shaped structure, respectively.

[0013] The aforementioned underwater crawling device for a nuclear reactor includes a plurality of body clearance structures on the body corresponding to the fuel assembly positioning pins and screws on the lower grid plate of the reactor core; and a plurality of lifting clearance structures on the lifting component corresponding to the fuel assembly positioning pins and screws on the lower grid plate of the reactor core.

[0014] The aforementioned underwater crawling device for nuclear reactors includes a translation component comprising a translation leg, a horizontal guide rod, and a horizontal power cylinder. One end of the horizontal guide rod is connected to the translation leg, and the other end of the horizontal guide rod is mounted inside the body and slides relative to the body. The horizontal power cylinder is disposed inside the body and is connected to both the translation leg and a drive control mechanism. The drive control mechanism drives the translation leg to switch between a translation extension position and a translation retraction position via the horizontal power cylinder.

[0015] The aforementioned underwater crawling device for nuclear reactors includes a lifting component comprising a lifting leg, a vertical guide rod, and a vertical power cylinder. One end of the vertical guide rod is connected to the lifting leg, and the other end is installed inside the translation leg and slides relative to the translation leg. A positioning guide pin is disposed on the bottom surface of the lifting leg. The vertical power cylinder is disposed inside the translation leg and is connected to both the lifting leg and a drive control mechanism. The drive control mechanism drives the lifting leg to switch between a lifting extended position and a lifting retracted position via the vertical power cylinder.

[0016] In the aforementioned underwater crawling device for nuclear reactors, the horizontal power cylinder and the vertical power cylinder are respectively a magnetically coupled rodless cylinder, a capsule-type thrust cylinder, a plunger cylinder, or a piston cylinder.

[0017] The aforementioned underwater crawling device for a nuclear reactor comprises a horizontal power cylinder, which is a piston cylinder including a horizontal cylinder body, a horizontal piston rod, and a horizontal piston. The horizontal cylinder body is disposed within the machine body. The horizontal piston is mounted on one end of the horizontal piston rod and disposed within the horizontal cylinder body. The other end of the horizontal piston rod is connected to the translation leg and drives the translation leg to switch between a translation extension position and a translation retraction position. The vertical power cylinder is also a piston cylinder, comprising a vertical cylinder body, a vertical piston rod, and a vertical piston. The vertical cylinder body is disposed within the translation leg. The vertical piston is mounted on one end of the vertical piston rod and disposed within the vertical cylinder body. The other end of the vertical piston rod is connected to the lifting leg and drives the lifting leg to switch between a lifting extension position and a lifting retraction position.

[0018] In the aforementioned underwater crawling device for nuclear reactors, the horizontal power cylinder and the vertical power cylinder are respectively double-acting cylinders or single-acting cylinders. When the horizontal power cylinder is a single-acting cylinder, a horizontal cylinder spring is also provided inside the horizontal cylinder body, and the horizontal cylinder spring is located in the piston rod-less side chamber or the piston rod side chamber of the horizontal cylinder body. When the vertical power cylinder is a single-acting cylinder, a vertical cylinder spring is also provided inside the vertical cylinder body, and the vertical cylinder spring is located in the piston rod-less side chamber or the piston rod side chamber of the vertical cylinder body.

[0019] The aforementioned underwater crawling device for nuclear reactors also includes a tool mounting section and a universal interface on its body.

[0020] The aforementioned underwater crawling device for nuclear reactors includes a drive control mechanism comprising a drive component, a pipeline, and a control valve. The drive component is connected to the translation component and the lifting component via the pipeline, and the control valve is connected to the pipeline. The control valve controls the connection or disconnection of the pipeline to enable the translation component and the lifting component to move sequentially in a set order.

[0021] The beneficial effects of this utility model are as follows:

[0022] This invention utilizes its own crawling mechanism to achieve positioning and autonomous movement on the lower core grid plate without relying on platforms or mechanical equipment above the reactor pool. This enables the random placement and autonomous relocation of tools required for maintenance of the lower core grid plate, reducing the need for operator observation and the difficulty of operation and maintenance work on the lower core grid plate. It solves the problems of existing technologies where manual alignment of tools with specific flow orifices on the lower core grid plate is required, resulting in difficult relocation operations, high workload, and high skill requirements for operators. Simultaneously, personnel do not need to work in an irradiated environment for extended periods, effectively reducing radiation dose and improving safety. It provides a more flexible positioning and movement method for tools required for maintenance of the lower core grid plate.

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Attached Figure Description

[0024] Figure 1A This is a schematic diagram of the working state of an embodiment of the present invention;

[0025] Figure 1B for Figure 1A Enlarged view of Part I;

[0026] Figure 2 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0027] Figure 3 This is a schematic diagram of the crawling mechanism structure according to an embodiment of the present invention;

[0028] Figure 4 This is a top view of a crawling mechanism according to an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the bottom structure of the crawling mechanism according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram showing the planar positional relationship between the crawling mechanism and the lower grid plate of the reactor core according to an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the crawling mechanism being raised according to an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the crawling leg structure according to an embodiment of the present invention;

[0033] Figure 9 This is a schematic diagram illustrating the working principle of a translation component according to an embodiment of the present invention.

[0034] Figure 10This is a schematic diagram illustrating the working principle of the translation component according to another embodiment of the present invention.

[0035] Figure 11 This is a schematic diagram illustrating the working principle of the translation component according to another embodiment of the present invention.

[0036] Figure 12 This is a schematic diagram illustrating the working principle of a lifting component according to an embodiment of the present invention.

[0037] Figure 13 This is a schematic diagram of the working principle of the lifting component according to another embodiment of the present invention;

[0038] Figure 14 This is a schematic diagram of the working principle of the lifting component in another embodiment of the present utility model.

[0039] Figure 15 This is a schematic diagram of the installation of a robotic arm according to an embodiment of the present invention;

[0040] Figure 16 This is a schematic diagram of the installation of a grinder according to an embodiment of the present invention;

[0041] Figure 17 This is a schematic diagram of a camera installation according to an embodiment of the present invention;

[0042] Figure 18 This is a schematic diagram of the installation of the guide cover according to an embodiment of the present invention;

[0043] Figure 19 for Figure 18 A schematic diagram of the working status.

[0044] Among them, the attached figures are labeled

[0045] 1 Underwater crawling device

[0046] 11 Drive Control Mechanism

[0047] 12 crawling mechanisms

[0048] 121 Tool Installation Department

[0049] 122 units

[0050] 1221 Airframe Guide Pin

[0051] 1222 fuselage bottom surface

[0052] 1223 Arc-shaped avoidance structure

[0053] 1224 square avoidance structure

[0054] 123 Crawling Legs

[0055] 1231 Translation Components

[0056] 12311 Translation Leg

[0057] 12312 Horizontal Guide Rod

[0058] 12313 Horizontal Power Cylinder

[0059] 12314 Horizontal Piston Rod

[0060] 12315 Horizontal Piston

[0061] 12316 Horizontal Cylinder Spring

[0062] 1232 Lifting Components

[0063] 12321 Lifting Leg

[0064] 12322 Vertical guide rod

[0065] 12323 Vertical Power Cylinder

[0066] 12324 Vertical piston rod

[0067] 12325 Vertical Piston

[0068] 12326 Vertical Cylinder Spring

[0069] 12327 Positioning Guide Pin

[0070] 12328 Lifting Arc-Shaped Avoidance Structure

[0071] 12329 Trapezoidal Avoidance Structure

[0072] 124 hoisting structure

[0073] 125 Universal Interface

[0074] 13 pipelines

[0075] 2 Reactor Pressure Vessel

[0076] 21 Core Lower Grid

[0077] 22 flow orifice

[0078] 23 Fuel Assembly Positioning Pins

[0079] 24 screws

[0080] 3 fuel assembly

[0081] 31 Lower tube seat

[0082] 4 guide covers

[0083] 41 Guide Inclined Surface

[0084] 5 robotic arms

[0085] 6 grinders

[0086] 7 cameras Detailed Implementation

[0087] The structural and working principles of this utility model will be described in detail below with reference to the accompanying drawings:

[0088] In the description of this application, it should be noted that the orientation indications of the terms "A", "B", "C", and "D" are based on the orientation or positional relationship of the underwater crawling device 1 in the reactor pressure vessel 2 as shown in Figure 1, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The terms "installation", "connection", and "joining" should be interpreted broadly unless otherwise expressly specified and limited.

[0089] See Figure 1A , 1B and Figure 2 , Figure 1A This is a schematic diagram of the working state of an embodiment of the present invention. Figure 1B for Figure 1A Enlarged view of part I, Figure 2 This is a schematic diagram of an embodiment of the present invention. The underwater crawling device 1 of the present invention is used in a nuclear reactor and includes: a drive control mechanism 11; and a crawling mechanism 12 connected to the drive control mechanism 11. The crawling mechanism 12 includes a body 122 and four crawling legs 123. Each crawling leg 123 includes a translation component 1231 and a lifting component 1232. The translation component 1231 is connected to the body 122, and the lifting component 1232 is connected to the translation component 1231. The drive control mechanism 11 controls the translation component 1231 and the lifting component 1232 to move sequentially according to a set order. The four crawling legs 123 cooperate to move the body 122 to a set position. The lifting component 1232 is equipped with a positioning guide pin 12327 corresponding to the flow orifice 22 of the lower core grid plate 21 within the reactor pressure vessel 2. The lifting component 12327 is inserted into the flow orifice 22 to achieve crawling movement. The bottom surface of the body 122 is provided with a body guide pin 1221 adapted to the flow orifice 22. The body guide pin 1221 is inserted into the flow orifice 22 to achieve positioning and is used to withstand the horizontal component force when guiding the fuel assembly. The crawling mechanism 12 can be made of materials such as 022Cr19Ni10 stainless steel or 022Cr17Ni12Mo2 stainless steel, preferably 022Cr17Ni12Mo2 stainless steel.

[0090] The drive control mechanism 11 includes a drive component, a pipeline 13, and a control valve. The drive component is connected to the translation component 1231 and the lifting component 1232 via the pipeline 13. The control valve is connected to the pipeline 13, and the control valve controls the connection or disconnection of the pipeline 13 to move the translation component 1231 and the lifting component 1232 sequentially according to a set order. That is, the translation and lifting movements of the crawling leg 123 are achieved through the control valve. The control valve can be located in the drive control mechanism 11 above water or in the crawling mechanism 12 underwater; there is no limitation in this regard. The control valve can be a directional valve or a sequence valve, preferably a directional valve. There can be multiple directional valves, preferably eight. A programmable logic controller can also be installed in the drive control mechanism to adjust the control valves to change their states according to a set order, thereby controlling the crawling mechanism 12 to crawl to the required working position on the lower grid plate of the reactor core according to a set pattern. Hydraulic or pneumatic media circulates within pipeline 13. The hydraulic or pneumatic media can be gas or deionized water, preferably deionized water, as its composition will not contaminate the reactor pool even if the sealing structure fails. The drive control mechanism 11 may also be equipped with wireless transmitting and receiving modules, allowing control via a wireless control handle. The drive control mechanism 11 may also have a reserved communication interface with the nuclear power plant's refueling system, enabling information exchange with the system via signal cables.

[0091] This embodiment may also include a lifting structure 124, which is mounted on the guide cover 4. The connection between the crawling mechanism 12 and the lifting structure 124 can be achieved through quick-connect hooks, threaded connections, welding, etc. Preferably, two quick-connect hooks are mounted on the top of the crawling mechanism 12 for easy disassembly. This allows the crawling mechanism 12 to be placed in different directions and positions within the reactor building in conjunction with the lifting facilities configured in the reactor building. Pipelines and lifting cables can be connected to the top of the crawling mechanism 12, and long-handled tools can be used to adjust the position of the pipelines and cables if necessary. When the crawling mechanism 12 is lifted into the pressure vessel, it can also descend along the surrounding plate. The two sides of the crawling mechanism 12 are brought into contact with the surrounding plate to help determine the placement direction of the crawling mechanism 12.

[0092] This embodiment also includes a universal interface 125 and a tool mounting section 121, which are disposed on the body 122, preferably on the top of the body 122, for connecting tools and implements related to the maintenance of the reactor core lower grid 21, such as guide tools, robotic arms, grinding tools, and cameras. The universal interface 125 provides power and signal transmission for the corresponding tools and implements; the tool mounting section 121 provides installation and positioning for the corresponding tools and implements. This structure reduces the difficulty of tasks such as fuel assembly loading guidance, foreign object retrieval, grid 21 maintenance, and underwater observation, greatly expanding the applicability of the underwater crawling device 1 and improving work efficiency.

[0093] See Figures 3-5, Figure 3 This is a schematic diagram of the crawling mechanism 12 according to an embodiment of the present invention. Figure 4 This is a top view of the crawling mechanism 12 according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the bottom structure of the crawling mechanism 12 according to an embodiment of the present invention. In this embodiment, the body 122 has an L-shaped structure, and the bottom surface of the body 122 is provided with a body guide pin 1221 that is adapted to the flow orifice 22 on the lower core grid plate 21 inside the reactor pressure vessel 2. The horizontal component force generated during the operation of the crawling mechanism 12 is borne by the body guide pin 1221 inserted into the flow orifice 22, and the horizontal power cylinder 12313 does not bear this horizontal component force. The vertical component force generated during the operation is directly transmitted from the bottom surface 1222 of the body to the lower core grid plate 21, and the vertical power cylinder 12323 does not bear this vertical component force. Preferably, the lower part of the body 122 is provided with three body guide pins 1221. After the crawling mechanism 12 is in place, the three body guide pins 1221 are inserted into the flow holes 22 corresponding to the core lower grid plate 21, realizing the precise positioning of the crawling mechanism 12. At the same time, the bottom surface 1222 of the body is in contact with the core lower grid plate 21. The end face and outer side of the L-shaped structure are respectively provided with the crawling legs 123, that is, there are four crawling legs 123, which are respectively installed at positions A, B, C and D of the body 122. Each crawling leg 123 has two degrees of freedom, which are accomplished by the translation component 1231 and the lifting component 1232 respectively. The translation component 1231 is installed on the side of the body 122 to realize the translation movement of the crawling leg 123. The lifting component 1232 is installed below the translation component 1231 to realize the lifting movement.

[0094] See Figure 6 , Figure 6 This is a schematic diagram showing the planar positional relationship between the crawling mechanism 12 and the fuel assembly positioning pins 23 and screws 24 on the lower core grid plate 21 according to an embodiment of the present invention. The body 122 is provided with multiple body avoidance structures corresponding to the lower core grid plate 21 inside the reactor pressure vessel 2. Preferably, the lower part of the body 122 is provided with an arc-shaped avoidance structure 1223 and a square avoidance structure 1224 that match the fuel assembly positioning pins 23. The arc-shaped avoidance structure 1223 and the square avoidance structure 1224 are used to prevent the body 122 from colliding with the fuel assembly positioning pins 23 and screws 24 on the surface of the lower core grid plate 21 when it descends.

[0095] This invention enables autonomous crawling movement on the lower core grid plate 21 using the flow orifices 22, without relying on man-bridges or mechanical equipment above the reactor pool. The crawling movement is a step-by-step movement, with each movement covering the distance between two adjacent flow orifices 22. Figure 7As shown, during the crawling movement, the lifting component 1232 lifts the body 122 to avoid the fuel assembly positioning pins 23 and screws 24 on the surface of the lower grid plate 21 of the reactor core.

[0096] See Figure 8 , Figure 8 This is a schematic diagram of the crawling leg 123 according to an embodiment of the present invention. In this embodiment, a positioning guide pin 12327 is disposed on the bottom surface of the lifting leg 12321 and corresponds to the flow orifice 22 of the lower core grid plate 21 within the reactor pressure vessel 2. When the crawling mechanism 12 moves, the positioning guide pin 12327 inserts into the flow orifice 22 of the lower core grid plate 21, thereby positioning the crawling leg 123 and bearing the reaction force during the movement of the crawling mechanism 12. The lifting leg 12321 is provided with multiple lifting avoidance structures corresponding to the fuel assembly positioning pins 23 and screws 24 on the lower core grid plate 21 within the reactor pressure vessel 2, including a lifting arc-shaped avoidance structure 12328 and a trapezoidal avoidance structure 12329, to prevent the lifting component 1232 from colliding with the fuel assembly positioning pins 23 and screws 24 on the surface of the lower core grid plate 21 when it descends.

[0097] See Figures 9-11 , Figure 9 This is a schematic diagram illustrating the working principle of the translation component 1231 according to an embodiment of the present invention, which employs a double-acting cylinder structure. Figure 10 This is a schematic diagram of the working principle of the translation component 1231 according to another embodiment of the present invention. It is a single-acting cylinder structure, and the horizontal cylinder spring 12316 is located in the side chamber without piston rod. Figure 11 This is a schematic diagram illustrating the working principle of the translation component 1231 according to another embodiment of the present invention. It is a single-acting cylinder structure with the horizontal cylinder spring 12316 located in the piston rod side chamber. In this embodiment, a horizontal power cylinder 12313 and two horizontal guide rods 12312 are provided between the translation component 1231 and the body 122. The two horizontal guide rods 12312 are symmetrically arranged on both sides of the horizontal power cylinder 12313. The horizontal power cylinder 12313 can be a magnetically coupled rodless cylinder, a capsule-type thrust cylinder, a plunger cylinder, or a piston cylinder. The capsule-type thrust cylinder can be a capsule-type single-acting piston thrust hydraulic cylinder, a capsule-type single-acting plunger hydraulic cylinder, etc. Both ends of the horizontal power cylinder 12313 can be connected to hoses, through which a medium is supplied to the horizontal power cylinder 12313 to provide power and cause the translation component 1231 to move. The other end of the hose is connected to a reversing valve assembly, which enables the reversing movement of the translation component 1231. The horizontal guide rod 12312 can slide axially to provide guidance for the translation component 1231.

[0098] The horizontal power cylinder in this embodiment is preferably a piston cylinder, including a horizontal cylinder body, a horizontal piston rod 12314, and a horizontal piston 12315. The translation component 1231 includes a translation leg 12311, a horizontal guide rod 12312, a horizontal cylinder body, a horizontal piston rod 12314, and a horizontal piston 12315. One end of the horizontal guide rod 12312 is connected to the translation leg 12311, and the other end of the horizontal guide rod 12312 is installed in a corresponding guide hole on the machine body 122, and moves along the guide hole relative to the machine body 122. The body 122 slides; the horizontal power cylinder 12313 can be a double-acting cylinder or a single-acting cylinder, preferably a double-acting cylinder, and is disposed in the body 122 and connected to the drive control mechanism 11; the horizontal piston 12315 is installed at one end of the horizontal piston rod 12314 and disposed in the horizontal cylinder body, which is disposed in the body 122; the other end of the horizontal piston rod 12314 is connected to the translation leg 12311 and drives the translation leg 12311 to switch between the translation extension position and the translation retraction position.

[0099] When the horizontal power cylinder 12313 is a double-acting cylinder, the piston rod-less side chamber and the piston rod-side chamber of the horizontal cylinder body are respectively connected to the reversing valve in the drive control mechanism 11 via hoses. Pressurized medium flows into the piston rod-less side chamber through the hoses, and the horizontal piston 12315 moves towards the piston rod side. The medium in the piston rod-side chamber flows back to the storage tank through the hoses, and the translation leg 12311 extends. After the reversing valve switches its state, pressurized medium flows into the piston rod-side chamber through the hoses, and the horizontal piston 12315 moves towards the piston rod-less side. The medium in the piston rod-less side chamber flows back to the storage tank through the hoses, and the translation leg 12311 retracts.

[0100] When the horizontal power cylinder 12313 is a single-acting cylinder, a horizontal cylinder spring 12316 is also provided inside the horizontal cylinder body. The horizontal cylinder spring 12316 can be located in the piston rod-less side chamber or the piston rod-side chamber of the horizontal cylinder body. If the horizontal cylinder spring 12316 is located in the piston rod-less side chamber, the piston rod-side chamber is connected to the reversing valve in the drive control mechanism 11 via a hose. Pressurized medium flows into the piston rod-side chamber through the hose, the horizontal piston 12315 moves towards the piston rod-less side, the horizontal cylinder spring 12316 is compressed, and the translation leg 12311 retracts. After the reversing valve switches states, the horizontal cylinder spring 12316 pushes the horizontal piston 12315 towards the piston rod side, the medium flows back to the storage tank through the hose, and the translation leg 12311 extends. If the horizontal cylinder spring 12316 is located in the piston rod side chamber, and the piston rod-less side chamber is connected to the reversing valve in the control mechanism via a hose, pressurized medium flows into the piston rod-less side chamber through the hose, causing the horizontal piston 12315 to move towards the piston rod side, compressing the horizontal cylinder spring 12316, and extending the translation leg 12311. After the reversing valve switches states, the horizontal cylinder spring 12316 pushes the horizontal piston 12315 towards the piston rod-less side, the medium flows back to the storage tank through the hose, and the translation leg 12311 retracts.

[0101] See Figure 12-14 , Figure 12 This is a schematic diagram illustrating the working principle of the lifting component 1232 according to an embodiment of the present invention. The vertical power cylinder 12323 is a double-acting cylinder structure. Figure 13 This is a schematic diagram of the working principle of the lifting component 1232 according to another embodiment of the present invention. The vertical power cylinder 12323 is a single-acting cylinder and the spring is located in the side chamber without the piston rod. Figure 14 This is a schematic diagram illustrating the working principle of the lifting component 1232 according to another embodiment of the present invention. The vertical power cylinder 12323 is a single-acting cylinder, and the spring is disposed in the piston rod side chamber. In this embodiment, a vertical power cylinder 12323 and two vertical guide rods 12322 are provided between the lifting component 1232 and the translation component 1231. The two vertical guide rods 12322 are symmetrically arranged on both sides of the vertical power cylinder 12323. The vertical power cylinder 12323 can be a magnetically coupled rodless cylinder, a capsule-type thrust cylinder, a plunger cylinder, or a piston cylinder. The capsule-type thrust cylinder can be a capsule-type single-acting piston thrust hydraulic cylinder, a capsule-type single-acting plunger hydraulic cylinder, etc. Both ends of the vertical power cylinder 12323 are connected to hoses, through which a medium is supplied to the vertical power cylinder 12323 to provide power to the vertical power cylinder 12323, causing the lifting component 1232 to move. The other end of the hose is connected to a reversing valve group, through which the reversing movement of the lifting component 1232 is realized. The vertical guide rod 12322 can slide axially to provide guidance for the lifting component 1232.

[0102] In this embodiment, the vertical power cylinder 12323 is preferably a piston cylinder. The lifting component 1232 includes a lifting leg 12321, a vertical guide rod 12322, a vertical power cylinder 12323, a vertical piston rod 12324, and a vertical piston 12325. One end of the vertical guide rod 12322 is connected to the lifting leg 12321, and the other end of the vertical guide rod 12322 is installed in a guide hole provided on the translation leg 12311 and slides relative to the translation leg 12311 along the guide hole. The vertical power cylinder 12323 can be a double-acting cylinder or a single-acting cylinder, preferably a double-acting cylinder, and is disposed in the translation leg 12311 and connected to the drive control mechanism 11; the vertical piston 12325 is installed at one end of the vertical piston rod 12324 and disposed in the vertical cylinder body of the vertical power cylinder 12323; the other end of the vertical piston rod 12324 is connected to the lifting leg 12321 and drives the lifting leg 12321 to switch between the lifting extension position and the lifting retracted position.

[0103] When the vertical power cylinder 12323 is a double-acting cylinder, the piston rod-less side chamber and the piston rod-side chamber are respectively connected to the reversing valve in the drive control mechanism 11 via hoses. Pressurized medium flows into the piston rod-less side chamber through the hoses, and the vertical piston 12325 moves towards the piston rod side. The medium in the piston rod-side chamber flows back to the storage tank through the hoses, and the lifting leg 12321 extends. After the reversing valve switches its state, pressurized medium flows into the piston rod-side chamber through the hoses, and the vertical piston 12325 moves towards the piston rod-less side. The medium in the piston rod-less side chamber flows back to the storage tank through the hoses, and the lifting leg 12321 retracts.

[0104] When the vertical power cylinder 12323 is a single-acting cylinder, a vertical cylinder spring 12326 is also provided inside the vertical power cylinder 12323. The vertical cylinder spring 12326 is located in either the piston rod-less side chamber or the piston rod-side chamber of the vertical power cylinder 12323. When the vertical cylinder spring 12326 is located in the piston rod-less side chamber, the piston rod-side chamber is connected to the reversing valve in the control mechanism via a hose. Pressurized medium flows into the piston rod-side chamber through the hose, the vertical piston 12325 moves towards the piston rod-less side, the vertical cylinder spring 12326 is compressed, and the lifting leg 12321 retracts. After the reversing valve switches states, the vertical cylinder spring 12326 pushes the vertical piston 12325 towards the piston rod side, the medium flows back to the storage tank through the hose, and the lifting leg 12321 extends. When the vertical cylinder spring 12326 is located in the piston rod-side chamber, the piston rod-less side chamber is connected to the reversing valve in the control mechanism via a hose. Pressurized medium flows into the piston rod-less side chamber through the hose, causing the vertical piston 12325 to move towards the piston rod side, compressing the vertical cylinder spring 12326, and extending the lifting leg 12321. After the directional valve switches states, the vertical cylinder spring 12326 pushes the vertical piston 12325 towards the piston rod-less side, the medium flows back to the storage tank through the hose, and the lifting leg 12321 retracts.

[0105] After the underwater crawling device 1 is equipped with the corresponding tools and implements in the tool mounting section 121, it can complete the maintenance work on the lower grid plate 21 of the reactor core. For example... Figure 15 As shown, after the underwater crawling device 1 has the robotic arm 5 installed in the tool mounting section 121, it can perform foreign object retrieval operations. Figure 16 As shown, after the underwater crawling device 1 installs the grinder 6 in the tool mounting section 121, it can perform grinding and repair of the lower core grid plate 21. Figure 17 As shown, after the underwater crawling device 1 has the camera 7 installed in the tool mounting section 121, it can perform underwater observation and inspection. Figure 18 and Figure 19 As shown, after the guide cover 4 is installed on the tool mounting part 121, the underwater crawling device 1 can provide auxiliary guidance for the positioning of fuel assembly loading. The guide cover 4 is adapted to the L-shaped body 122 and is installed on the tool mounting part 121 on the top of the body 122. Each (6) side of the guide cover 4 connected to the body 122 is provided with a guide ramp 41. The guide ramps 41 are connected by an arc transition. The angle between the guide ramp 41 and the horizontal plane is 55 degrees to 70 degrees, preferably 60 degrees, which can adapt to the loading guidance of fuel assembly 3 under various working conditions. Different guide covers 4 can be removed and replaced according to the loading guidance requirements of different reactors. The guide cover 4 is preferably a sheet metal part, which can withstand cushioning and avoid accidental damage to the fuel assembly 3.

[0106] Reused fuel assemblies inevitably undergo bending and torsional deformation after a three-stage nuclear reaction. When loading such fuel assemblies, the loading / unloading machine may encounter difficulties in inserting the lower mounting bracket 31 of the fuel assembly 3 into the fuel assembly positioning pin 23 on the lower core grid plate 21. Using a guiding tool during loading can improve the reliability of the loading and positioning. Figure 18 As shown, the guide cover 4 is mounted to the body 122 via the tool mounting part 121. The guide cover 4 has a guide ramp 41 along which the fuel assembly 3 can be guided to the correct loading position. The underwater crawling device 1 can carry the guide cover 4 to any position providing guidance for the fuel assembly 3 as needed. Figure 19 As shown, with the assistance of the guide cover 4, the fuel assembly 3 successfully inserts the lower tube seat 31 of the fuel assembly 3 into the fuel assembly positioning pin 23 on the lower grid plate 21 of the reactor core.

[0107] This invention utilizes its own crawling mechanism 12 to achieve positioning and autonomous crawling on the lower core grid plate 21 without relying on platforms or mechanical equipment above the reactor pool. This enables the random placement and autonomous relocation of tools required for maintenance of the lower core grid plate 21, reducing the operator's observation needs and the difficulty of operation and maintenance work on the lower core grid plate 21. It solves the problems of existing technologies where tools need to be manually aligned with specific flow orifices 22 on the lower core grid plate 21, resulting in difficult relocation operations, high workload, and high skill requirements for operators. Simultaneously, personnel do not need to work in an irradiated environment for extended periods, effectively reducing radiation dose and improving safety. It provides a more flexible positioning and movement method for tools required for maintenance of the lower core grid plate 21.

[0108] Of course, there may be other embodiments of this utility model. Without departing from the spirit and essence of this utility model, those skilled in the art can make various corresponding changes and modifications based on this utility model, but these corresponding changes and modifications should all fall within the protection scope of the appended claims of this utility model.

Claims

1. An underwater crawling device for nuclear reactors, characterized in that, include: Drive control mechanism; as well as A crawling mechanism is connected to the drive control mechanism. The crawling mechanism includes a body and multiple crawling legs. Each crawling leg includes a translation component and a lifting component. The translation component is connected to the body, and the lifting component is connected to the translation component. The drive control mechanism controls the translation component and the lifting component to move sequentially in a set order. The multiple crawling legs cooperate with each other to drive the body to crawl and move to a set position. The lifting component is provided with a positioning guide pin corresponding to the flow hole of the core lower grid plate in the reactor pressure vessel, and the crawling movement is achieved by inserting the positioning guide pin into the flow hole; the bottom surface of the body is provided with a body guide pin adapted to the flow hole, and the positioning is achieved by inserting the body guide pin into the flow hole.

2. The underwater crawling device for a nuclear reactor as described in claim 1, characterized in that, The body is an L-shaped structure adapted to the fuel assembly, and the crawling legs are respectively provided on the end face and the outer side of the L-shaped structure.

3. The underwater crawling device for a nuclear reactor as described in claim 1, characterized in that, The body is provided with multiple body clearance structures corresponding to the fuel assembly positioning pins and screws on the lower grid plate of the reactor core; the lifting component is provided with multiple lifting clearance structures corresponding to the fuel assembly positioning pins and screws on the lower grid plate of the reactor core.

4. The underwater crawling device for a nuclear reactor as described in claim 1, characterized in that, The translation component includes a translation leg, a horizontal guide rod, and a horizontal power cylinder. One end of the horizontal guide rod is connected to the translation leg, and the other end of the horizontal guide rod is installed in the body of the machine and slides relative to the body of the machine. The horizontal power cylinder is disposed in the body of the machine and is connected to the translation leg and the drive control mechanism respectively. The drive control mechanism drives the translation leg to switch between a translation extension position and a translation retraction position through the horizontal power cylinder.

5. The underwater crawling device for a nuclear reactor as described in claim 4, characterized in that, The lifting component includes a lifting leg, a vertical guide rod, and a vertical power cylinder. One end of the vertical guide rod is connected to the lifting leg, and the other end of the vertical guide rod is installed inside the translation leg and slides relative to the translation leg. The positioning guide pin is disposed on the bottom surface of the lifting leg. The vertical power cylinder is disposed inside the translation leg and is connected to the lifting leg and the drive control mechanism respectively. The drive control mechanism drives the lifting leg to switch between the lifting extended position and the lifting retracted position through the vertical power cylinder.

6. The underwater crawling device for a nuclear reactor as described in claim 5, characterized in that, The horizontal power cylinder and the vertical power cylinder are respectively a magnetically coupled rodless cylinder, a capsule-type thrust cylinder, a plunger cylinder, or a piston cylinder.

7. The underwater crawling device for a nuclear reactor as described in claim 6, characterized in that, The horizontal power cylinder is a piston cylinder, including a horizontal cylinder body, a horizontal piston rod, and a horizontal piston. The horizontal cylinder body is disposed within the machine body. The horizontal piston is installed at one end of the horizontal piston rod and disposed within the horizontal cylinder body. The other end of the horizontal piston rod is connected to the translation leg and drives the translation leg to switch between a translation extension position and a translation retraction position. The vertical power cylinder is a piston cylinder, including a vertical cylinder body, a vertical piston rod, and a vertical piston. The vertical cylinder body is disposed within the translation leg. The vertical piston is installed at one end of the vertical piston rod and disposed within the vertical cylinder body. The other end of the vertical piston rod is connected to the lifting leg and drives the lifting leg to switch between a lifting extension position and a lifting retraction position.

8. The underwater crawling device for a nuclear reactor as described in claim 7, characterized in that, The horizontal power cylinder and the vertical power cylinder are either double-acting cylinders or single-acting cylinders, respectively. When the horizontal power cylinder is a single-acting cylinder, a horizontal cylinder spring is also provided inside the horizontal cylinder body. The horizontal cylinder spring is located in the piston rod-less side chamber or the piston rod side chamber of the horizontal cylinder body. When the vertical power cylinder is a single-acting cylinder, a vertical cylinder spring is also provided inside the vertical cylinder body. The vertical cylinder spring is located in the piston rod-less side chamber or the piston rod side chamber of the vertical cylinder body.

9. The underwater crawling device for a nuclear reactor as described in claim 1, characterized in that, The machine body is also equipped with a tool mounting section and a universal interface.

10. The underwater crawling device for a nuclear reactor as described in claim 1, characterized in that, The drive control mechanism includes a drive component, pipelines, and a control valve. The drive component is connected to the translation component and the lifting component respectively through the pipelines. The control valve is connected to the pipelines. The control valve controls the connection or disconnection of the pipelines to enable the translation component and the lifting component to move sequentially in a set order.

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