Bar taking device and bar changing method

Abstract

This invention discloses a fuel rod retrieval device and a fuel rod replacement method, including a housing, a power unit and an execution unit disposed within the housing, and a control unit communicatively connected to the power unit. The execution unit includes a core rod, grippers, a locking tube, and an outer tube. The core rod, grippers, and locking tube are disposed within the outer tube and are movable along the axial direction of the outer tube. The locking tube is sleeved on the core rod and grippers and is movable along the axial direction of the core rod. Both ends of the core rod are connected to the power unit and the grippers, respectively. The end of the grippers away from the core rod is provided with a pawl for gripping the fuel rod to be replaced. This fuel rod retrieval device can safely extract the fuel rod to be replaced from the new fuel assembly.

Description

Technical Field

[0001] This invention relates to the field of new fuel assembly maintenance technology for nuclear power plants, and in particular to a rod removal device and rod replacement method. Background Technology

[0002] Currently, to prevent potential accidental loss of new fuel assemblies, each nuclear power plant unit stores a certain number of new fuel assemblies. Domestic nuclear power plants lack the equipment and technology to perform new fuel assembly repair work inside the plant, leaving the field of new fuel assembly repair in a blank state. When a defective fuel rod appears in a new fuel assembly, the only solution is to package the new fuel assembly and return it to the factory for reassembly and repair. Implementing this solution is not only time-consuming, costly, and complex, but also carries the risk of secondary damage to the fuel assembly during the return process. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a rod-removing device and a rod-changing method.

[0004] The technical solution adopted by the present invention to solve its technical problem is: to construct a rod-picking device, including a housing, a power unit and an execution unit disposed in the housing, and a control unit communicatively connected to the power unit;

[0005] The execution unit includes a core rod, a gripper, a locking tube, and an outer tube. The core rod, the gripper, and the locking tube are disposed inside the outer tube and are movable along the axial direction of the outer tube. The locking tube is sleeved on the core rod and the gripper and is movable along the axial direction of the core rod. Both ends of the core rod are connected to the power unit and the gripper, respectively. The end of the gripper away from the core rod is provided with a ratchet for gripping the fuel rod to be replaced.

[0006] Preferably, in the rod-retrieving device of the present invention, the power unit includes a motor, a drum, and a lifting rope; the motor is connected to the drum; the drum is connected to the housing; and the two ends of the lifting rope are respectively connected to the drum and the core rod.

[0007] Preferably, in the rod-retrieving device of the present invention, the execution unit further includes a counterweight, which is sleeved on the outer sleeve and can move along the axial direction of the outer sleeve; the lifting rope is connected to the core rod through the counterweight.

[0008] Preferably, in the rod-retrieving device of the present invention, the counterweight includes an annular member and a reinforcing plate. The annular member is sleeved on the outer peripheral wall of the outer sleeve, and the reinforcing plate passes through the annular member and the outer sleeve in sequence along the radial direction of the annular member. The two sides of the reinforcing plate are respectively connected to the lifting rope and the core rod.

[0009] Preferably, in the rod-retrieving device of the present invention, the number of the lifting ropes is at least two, and the stiffening plate is provided with a first through hole, at least two second through holes and a first screw hole;

[0010] The first through hole extends along the axial direction of the outer sleeve and is located close to the power unit; the first screw hole is located away from the power unit and is used to connect with the core rod; a gap is left between the first through hole and the first screw hole, and at least two second through holes are respectively located on both sides of the gap, and the second through holes extend along the axial direction perpendicular to the outer sleeve.

[0011] One end of each of the hoisting ropes passes sequentially through the first through hole and the corresponding second through hole and then extends out of the stiffening plate;

[0012] The counterweight also includes a clamping cover, which is connected to the stiffening plate and is used to clamp the end of each of the suspension ropes that extends out of the stiffening plate.

[0013] Preferably, in the rod-retrieving device of the present invention, the core rod includes a body portion, a first threaded section, a second threaded section, and a third threaded section;

[0014] The first threaded segment is located at one end of the body and is inserted into the first threaded hole for connection; the third threaded segment is located at the other end of the body and is connected to the clamp; the second threaded segment is located between the first threaded segment and the third threaded segment and is connected to the locking tube.

[0015] Preferably, in the rod-retrieving device of the present invention, the outer sleeve includes at least two strip-shaped members with annular cross-sections. The at least two strip-shaped members surround each other for the core rod, the gripper, and the locking tube to pass through. There is a strip-shaped channel between two adjacent strip-shaped members. The strip-shaped channel extends axially, and the two ends of the stiffener pass through the strip-shaped channel and are connected to the annular members.

[0016] Preferably, in the rod-taking device of the present invention, the strip-shaped member includes an inner strip-shaped segment and an outer strip-shaped segment, the outer strip-shaped segment is disposed on the outer peripheral wall of the inner strip-shaped segment and is connected to the inner strip-shaped segment.

[0017] Preferably, in the rod-retrieving device of the present invention, the outer sleeve further includes an upper end cap, a lower end cap, and at least two support rods;

[0018] The upper end cover is connected to and fixed to the end of the outer strip near the power unit, and at least two of the outer strips are fixed. The upper end cover is provided with a central through hole for the suspension rope to pass through.

[0019] One side of the lower end cover is connected to and fixed to the end of the outer strip segment away from the power unit, and at least two of the outer strip segments are fixed thereto. The other side of the lower end cover is provided with a protective tube for the fuel rod to be replaced to pass through.

[0020] One end of at least two of the support rods is connected to at least two of the outer strip segments, and the other end of the two support rods is connected and fixed to the box body.

[0021] Preferably, in the rod-picking device of the present invention, the rod-picking device further includes a torque sensor and an encoder; the power unit further includes a guide wheel;

[0022] The guide wheel is located between the drum and the outer sleeve; the suspension rope is wound around the guide wheel and extends out to connect with the counterweight;

[0023] One end of the torque sensor is connected to the guide wheel, and the other end of the torque sensor is connected to the encoder.

[0024] Preferably, in the rod-retrieving device of the present invention, the rod-retrieving device further includes a limiter; the limiter is communicatively connected to the control unit, the limiter is partially disposed inside the housing near the counterweight, a portion of the limiter's limiting piece extends out of the housing and is used to make positive contact with the counterweight, and the limiter is triggered to operate.

[0025] Preferably, in the rod-picking device of the present invention, the control unit includes a PLC module for processing data and sending control signals, a motor drive module for controlling the rotation direction and speed of the motor, an industrial machine for setting parameters, monitoring and processing data, a wireless transmission module and a wireless receiving module for establishing communication between the industrial machine and the PLC module, a control panel for displaying and modifying parameters, a controller for controlling the operation of the motor, and an antenna for providing wireless signal transmission and reception.

[0026] The PLC module, the motor drive module, the wireless transmitting module, and the wireless receiving module are all housed inside the enclosure; the control panel and the antenna are located on the outside of the enclosure.

[0027] The outer side of the enclosure is provided with an operator port; the operator is connected to the operator port or the operator uses a wireless connection.

[0028] The present invention also discloses a rod replacement method, using the rod-taking device described in any of the above claims, comprising the following steps:

[0029] S10: Use an auxiliary hoist to lift the rod-retrieving device and align it with the position of the fuel rod to be replaced;

[0030] S20: Lower the auxiliary hoist main lifting mechanism and align the outer sleeve vertically with the guide hole on the guide plate corresponding to the position of the fuel rod to be replaced;

[0031] S30: Start the power unit to lower the core rod, gripper and locking tube. Stop the power unit operation when the locking tube protrudes outside the outer tube and approaches the top of the fuel rod to be replaced.

[0032] S40: Rotate the locking tube to move along the core rod in a direction away from the pawl, so that the pawl of the gripper opens;

[0033] S50: Continue to start the power unit to lower the core rod, so that the pawl surrounds the outer periphery of the end of the fuel rod to be replaced and stop the power unit from operating;

[0034] S60: Rotate the locking tube and move it along the core rod toward the pawl, so that the pawl is put into the locking tube and closed to clamp the outer periphery of the end of the fuel rod to be replaced;

[0035] S70: Start the power unit to raise the core rod, the gripper drives the fuel rod to be replaced to rise, and stop the power unit when the fuel rod to be replaced is completely inside the outer tube;

[0036] S80: Raise the auxiliary hoist main hoist and move the rod taking device above the temporary storage container opening, and put the fuel rod to be replaced into the temporary storage container;

[0037] S90: Use the rod-grabbing device to grab the stainless steel replacement rod and insert the stainless steel replacement rod back into the original position of the fuel rod to be replaced.

[0038] Preferably, in the rod replacement method of the present invention, step S90 includes:

[0039] S91: Use the rod-grabbing device to grab the stainless steel replacement rod and start the power unit to raise the core rod. The gripper drives the stainless steel replacement rod to rise. When the stainless steel replacement rod is completely inside the outer tube, stop the operation of the power unit.

[0040] S92: Use the auxiliary hoist to move the rod-retrieving device above the original position of the fuel rod to be replaced;

[0041] S93: Lower the auxiliary hoist main lifting mechanism to vertically align the outer sleeve with and bring it close to the original position of the fuel rod to be replaced;

[0042] S94: Start the power unit to lower the core rod and fully insert the stainless steel replacement rod into the original position of the fuel rod to be replaced. Attached Figure Description

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0044] Figure 1 This is a schematic diagram of the overall structure of the rod-taking device of the present invention;

[0045] Figure 2 This is a partial structural schematic diagram of the rod-taking device of the present invention;

[0046] Figure 3 This is a partial cross-sectional schematic diagram of the rod-removing device of the present invention;

[0047] Figure 4 This is the present invention. Figure 3 An enlarged schematic diagram of the execution unit within the middle circle;

[0048] Figure 5 This is a perspective view of the counterweight block of the present invention;

[0049] Figure 6 This is the present invention. Figure 4 A schematic diagram of the stiffening ribs in the diagram;

[0050] Figure 7 This is a schematic diagram of the core rod of the present invention;

[0051] Figure 8 This is a schematic diagram of the gripper structure of the present invention;

[0052] Figure 9 This is a schematic diagram of the locking tube of the present invention;

[0053] Figure 10 Figures a, b, and c are schematic diagrams of the outer sleeve of the present invention in different directions;

[0054] Figure 11 This is a diagram showing the released state of the gripper of the present invention;

[0055] Figure 12 This is a diagram showing the locking state of the gripper of the present invention;

[0056] Figure 13 This is a flowchart of the rod replacement method of the present invention. Detailed Implementation

[0057] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0058] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0059] In the description of the invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element 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 of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of the invention, unless otherwise stated, "a plurality of" means two or more.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a chemical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] Furthermore, the flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0062] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0063] See Figures 1 to 12 An embodiment of the present invention discloses a rod-retrieving device, including a housing 5, a power unit 1 and an execution unit 2 disposed within the housing 5, and a control unit 3 communicatively connected to the power unit 1; the control unit 3 is connected to the power unit 1 and controls the operation of the power unit 1; the power unit 1 is connected to the execution unit 2 and drives the execution unit 2 to move.

[0064] Specific combination Figure 3 and Figure 9The execution unit 2 includes a core rod 22, a gripper 23, a locking tube 24, and an outer tube 25. One end of the outer tube 25 is fixedly connected to the inside of the housing 5, and the other end extends outside the housing 5. The core rod 22, gripper 23, and locking tube 24 are disposed inside the outer tube 25, and all three can move axially along the outer tube 25. The locking tube 24 is sleeved on the core rod 22 and the gripper 23, and can move axially along the core rod 22. Both ends of the core rod 22 are connected to the power unit 1 and the gripper 23, respectively. The end of the gripper 23 away from the core rod 22 is provided with a pawl 231 for gripping the fuel rod 6 to be replaced. To adjust the tightening torque of the gripper 23, a tightening notch is provided on the gripper 23 for a wrench to hold. Its specific working principle is as follows:

[0065] Since the power unit 1 is connected to the core rod 22, it can drive the core rod 22 to move axially along the outer sleeve 25, thereby driving the gripper 23 and the locking tube 24 to move simultaneously, so that the locking tube 24 can be exposed outside the outer sleeve 25 or extended into the outer sleeve 25. When the locking tube 24 is exposed outside the outer sleeve 25, it is convenient to push the locking tube 24 to move axially along the core rod 22. In this embodiment, the locking tube 24 can be pushed manually.

[0066] Furthermore, the locking tube 24 is respectively sleeved on the core rod 22 and the pawl 23, and the locking tube 24 can move along the axial direction of the core rod 22, so that the pawl 231 can be exposed outside the locking tube 24 or sleeved inside the locking tube 24. That is, when the locking tube 24 moves along the core rod 22 in a direction away from the pawl 231, the pawl 231 is exposed outside the locking tube 24 and automatically opens; while when the locking tube 24 moves along the core rod 22 in a direction close to the pawl 231, the pawl 231 is sleeved inside the locking tube 24 and automatically closes, and grips the end of the fuel rod 6 to be replaced.

[0067] The rod removal device of this invention is mainly used in new fuel assemblies of megawatt-class nuclear power plants to extract defective fuel rods 6 that are to be replaced from the new fuel assembly. During the extraction of the fuel rod 6, the power unit 1 drives the core rod 22 to descend toward the fuel rod 6, thereby driving the jaws 23 and the locking tube 24 to move. When the locking tube 24 protrudes outside the outer sleeve 25, the locking tube 24 moves along the core rod 22 in a direction away from the jaws 231, thereby exposing the jaws 231 outside the locking tube 24. The locking tube 24 automatically opens and surrounds the end of the fuel rod 6 to be replaced. Then, the locking tube 24 moves along the core rod 22 toward the pawl 231. The pawl 231 is put into the locking tube 24 and automatically closes, thereby gripping the end of the fuel rod 6 to be replaced. Finally, the core rod 22 is driven to rise by the power unit 1, so that the locking tube 24 extends into the outer tube 25, thereby completely enclosing the extracted fuel rod 6 to be replaced in the outer tube 25, preventing the fuel rod 6 to be replaced from being damaged again during the movement.

[0068] It should be noted that, in order to ensure the integrity of the new fuel assembly and not affect its overall performance, a replacement fuel rod needs to be inserted back into the original position of the replacement fuel rod 6. Since nuclear fuel rods are strictly controlled by the National Nuclear Safety Administration and are not easily obtained, readily available stainless steel rods can be used as direct replacements. After the defective replacement fuel rod 6 has been removed, the rod removal device can be used to reinsert the stainless steel rod into its original position within the new fuel assembly. When the stainless steel rod is inserted into the original position of the replacement fuel rod 6, the power unit 1 drives the core rod 22 to descend. Since the weight of the stainless steel rod is insufficient to completely press itself back into the fuel assembly frame, external force is needed to press the stainless steel rod down to help it fully return to the original state of the replacement fuel rod 6.

[0069] Specifically:

[0070] To achieve the function of driving the core rod 22, such as Figure 2 As shown, the power unit 1 includes a motor 11, a drum 12, and a lifting rope 13. The motor 11 is connected to the drum 12; the drum 12 is connected to the housing 5; the two ends of the lifting rope 13 are connected to the drum 12 and the core rod 22, respectively. The motor 11 drives the drum 12, which in turn drives the lifting rope 13, which in turn drives the core rod 22 to move, thereby driving the gripper 23 to move. The drum 12 is fixed inside the housing 5 by a fixing frame. Preferably, the motor 11 is a stepper motor, and the lifting rope 13 is a steel wire rope.

[0071] To help the stainless steel rod be fully positioned in the original state of the fuel rod to be replaced 6, pressure is applied when the stainless steel rod is inserted into the original position of the fuel rod to be replaced 6. See [link to relevant documentation]. Figures 1 to 5 The execution unit 2 also includes a counterweight 21, which is fitted onto the outer sleeve 25 and can move axially along the outer sleeve 25; the lifting rope 13 is connected to the core rod 22 through the counterweight 21. The counterweight 21 serves as a connection medium between the power unit 1 and the core rod.

[0072] Furthermore, such as Figure 5 As shown, the counterweight 21 includes an annular component and a stiffening plate 211. The annular component is fitted onto the outer peripheral wall of the outer sleeve 25, and the stiffening plate 211 passes through the annular component and the outer sleeve 25 radially. The two sides of the stiffening plate 211 are connected to the suspension rope 13 and the core rod 22, respectively. The side of the stiffening plate 211 closer to the power unit 1 is connected to the suspension rope 13, and the other side of the stiffening plate 211 away from the power unit 1 is connected to the core rod 22. The annular component is cylindrical, made of stainless steel, and has a central through hole for fitting onto the outer sleeve 25. The stiffening plate 211 passes radially through the center of the counterweight 21 to balance the gravity on both sides. Preferably, one end of the suspension rope 13 passes through the end of the outer sleeve 25 and enters the central through hole of the annular component, reaching the stiffening plate 211 and connecting to the end of the stiffening plate 211 closer to the power unit 1.

[0073] Furthermore, such as Figure 5 As shown, there are at least two suspension ropes 13. The stiffening plate 211 is provided with a first through hole 212, at least two second through holes 213, and a first screw hole 214. The first through hole 212 extends along the axial direction of the outer sleeve 25 and is located close to the power unit 1. The first screw hole 214 is located away from the power unit 1 and is used to connect with the core rod 22. There is a gap between the first through hole 212 and the first screw hole 214. At least two second through holes 213 are respectively provided on both sides of the gap, and the second through holes 213 extend along the axial direction perpendicular to the outer sleeve 25. One end of each suspension rope 13 passes through the first through hole 212 and the corresponding second through hole 213 in sequence and extends out of the stiffening plate 211. The counterweight block 21 also includes a pressing cover 216, which is connected to the stiffening plate 211 and is used to press the end of each suspension rope 13 that extends out of the stiffening plate 211. Preferably, the first through hole 212 is located in the middle of the stiffening plate 211 along the axial direction of the outer sleeve 25. To secure at least two lifting ropes 13, four second screw holes 215 can be provided for bolt insertion. The four second screw holes 215 are evenly distributed on the outer wall of the stiffening plate 211 above at least two second through holes 213. The lifting rope 13 passes through the second through hole 213 to the second screw hole 215, and is secured and tightened by a corresponding clamping cap 216. A bolt is inserted from the outside of the clamping cap 216 into the second screw hole 215 to tighten the lifting rope 13. In some other embodiments, knotting or other methods can also be used to fix the end of the lifting rope 13 to the outside of the second through hole 213.

[0074] Core rod 22 is the central component of actuator 2. To establish a connection between core rod 22 and the counterweight, gripper 23, and locking tube 24, as follows: Figure 7 As shown, the core rod 22 includes a body part 224, a first threaded section 221, a second threaded section 222 and a third threaded section 223;

[0075] The first threaded section 221 is located at one end of the body portion 224 and is inserted into the first threaded hole 214 of the reinforcing rib 211 and connected to the first threaded hole; the third threaded section 223 is located at the other end of the body portion 224 and is connected to the gripper 23; the second threaded section 222 is located near the third threaded section 223, between the first threaded section 221 and the third threaded section 223, and is connected to the locking tube 24. Preferably, the first end 241 of the locking tube 24 is connected to the second threaded section 222, and the first end 241 of the locking tube 24 is provided with a corresponding internal thread, and the portion of the gripper 23 connected to the third threaded section 223 is provided with a corresponding external thread.

[0076] The locking tube 24 controls the opening and closing state of the pawl 231 of the gripper 23. The second end 242 of the locking tube 24 engages with the gripper 23. The power unit 1 drives the core rod 22 to descend, and the core rod 22 moves along the outer sleeve 25 so that the locking tube 24 protrudes outside the outer sleeve 25 or extends into the outer sleeve 25. When the locking tube 24 protrudes outside the outer sleeve 25, the relative position of the locking tube 24 with respect to the gripper 23 is changed by manually rotating the locking tube 24. The bottom of the locking tube 24 engages with the pawl 231, and the pawl 231 engages with the upper end plug of the fuel rod 6 to be replaced, realizing the opening and closing operation of the gripper 23 on the fuel rod 6 to be replaced. Figure 11 As shown, the gripper 23 is in the released state, with the pawl 231 protruding outside the locking tube 24 and the pawl 231 in a free state; therefore, the gripper 23 is in the released state. Figure 12 As shown, the gripper 23 is in the locked state. When the pawl 231 is fully inserted into the second end 242 of the locking tube 24 and the pawl 231 is tightly closed by external force, the gripper 23 is in the locked state. Preferably, the pawl 231 is an eight-petal-shaped pawl 231.

[0077] To provide a fixed travel path for the counterweight 21, core rod 22, locking tube 24, and gripper 23, and to provide containment and protection for the extracted fuel rod 6 to be replaced. Figure 3 , Figure 4 and Figure 10 As shown, the outer sleeve 25 includes at least two annular strips with a cross-section. The at least two strips enclose the core rod 22, the gripper 23, and the locking tube 24 for passage. A strip channel is formed between two adjacent strips, extending axially. The two ends of the stiffener 211 pass through the strip channel and are connected to the annular strips. The strip channel serves as the movement path for the stiffener 211.

[0078] Further, the strip-shaped component includes an inner strip segment 251 and an outer strip segment 252. The outer strip segment 252 is disposed on the outer peripheral wall of the inner strip segment 251 and connected to the inner strip segment 251. At least two strip-shaped components include at least two inner strip segments 251 and at least two outer strip segments 252. Preferably, there are two inner strip segments 251 and two outer strip segments 252. The two inner strip segments 251 form a moving protection channel for the core rod 22, the gripper 23, the locking tube, and the fuel rod 6 to be replaced. The two outer strip segments 252 provide a moving path for the annular component. The inner strip segment 251 and the outer strip segment 252 can be fixed by spot welding with reinforcing ribs. Generally, multiple pairs of reinforcing ribs are used, and the spot welding positions of the reinforcing ribs are evenly distributed.

[0079] To secure the outer sleeve 25, this includes fixing the outer sleeve to the housing 5 and fixing at least two outer strip segments 252, such as... Figure 10As shown in Figures b and c, the outer casing 25 also includes an upper end cap 253, a lower end cap 254, and at least two support rods 255; the two ends of the two outer strip segments 252 are fixed by the upper end cap 253 and the lower end cap 254; the upper end cap 253 is connected to and fixes at least two outer strip segments 252 near the end of the outer strip segments 252 close to the power unit 1, and the upper end cap 253 has a central through hole for the hoisting rope 13 to pass through; one side of the lower end cap 254 is connected to and fixes at least two outer strip segments 252 away from the power unit 1, and the other side of the lower end cap 254 has a protective tube 256 for the fuel rod 6 to be replaced to pass through; the protective tube 256 can also be used to assist in aligning the position of the fuel rod 6 to be replaced;

[0080] At least two support rods 255 have one end connected to at least two outer strip segments 252, and the other end of the two support rods 255 are respectively connected and fixed to the housing 5 to fix the outer sleeve 25 to the housing 5. Preferably, there are two support rods 255, matching the number of outer strip segments 252.

[0081] To monitor the speed and friction of the gripper 23 during its up-and-down movement, such as Figure 2 As shown, the rod-picking device also includes a torque sensor 41 and an encoder 42; the power unit 1 also includes a guide wheel 14; the guide wheel 14 is located between the drum 12 and the outer tube 25; the lifting rope 13 is wound around the guide wheel 14 and extends out to connect with the counterweight 21; preferably, the lifting rope 13 first passes through the central through hole of the upper end cap 253 of the outer tube 25 before connecting with the counterweight 21.

[0082] One end of the torque sensor 41 is connected to the guide wheel 14, and the other end is connected to the encoder 42. The encoder 42 and the torque sensor 41 are used to collect the rotational speed and force of the guide wheel, thereby monitoring the speed and friction of the gripper during its up-and-down movement. Preferably, the suspension rope 13 squeezes the guide wheel 14 and only needs to be wound around the guide wheel 14 less than once. The guide wheel 14, the encoder 42, and the torque sensor 41 are connected by rotating shafts.

[0083] The rod-retrieving device also includes a limiter 43; the limiter 43 is communicatively connected to the control unit 3, and part of the limiter 43 is located inside the housing 5 near the counterweight 21. One end of the limiter plate 431 of the limiter 43 extends out of the housing 5 and is used to make direct contact with the counterweight 21 to trigger the action of the limiter 43. When the counterweight 21 comes into contact with the limiter plate 431 near the top plane of the power unit 1, the limiter 43 is triggered to stop the motor 11 from rotating, preventing human error.

[0084] To precisely control the speed of the motor 11, the power unit 1 also includes a gearbox 15; one end of the gearbox 15 is connected to the motor 11, and the other end is connected to the drum 12. The power of the motor 11 is transmitted to the drum 12 through the gearbox 15. The suspension rope 13 on the drum 12 passes through the guide wheel 14 and is connected to the counterweight 21. The counterweight 21 is connected to the core rod 22. By controlling the forward and reverse rotation of the motor 11 and the rotation speed of the motor 11, the up-and-down movement and speed of the core rod 22 can be controlled.

[0085] In order to control the operation of power unit 1, such as Figure 2 As shown, the control unit 3 includes a PLC module 31 for processing data and sending control signals, a motor drive module for controlling the rotation direction and speed of the motor 11, an industrial unit for setting equipment parameters, monitoring, and processing data, a wireless transmission module and a wireless reception module for establishing communication between the industrial unit and the PLC module 31, a control panel 32 for displaying and modifying parameters, a controller for controlling the operation of the motor 11, and an antenna 33 for providing wireless signal transmission and reception. Preferably, the wireless transmission module and the wireless reception module are 485 wireless transmission modules and 485 wireless reception modules. The PLC module 31 is used to process data and send control signals to the motor drive module; the motor drive module is used to control the rotation direction and speed of the motor 11; the 485 wireless transmission module and the 485 wireless reception module are used to establish communication between the industrial unit and the PLC module 31; the industrial unit is used for setting equipment parameters, monitoring, and processing data, and can be any type of data processing terminal.

[0086] The PLC module 31, motor drive module, wireless transmitter module, and wireless receiver module are all located inside the housing 5. The housing 5 is equipped with a mounting support structure to fix each module. The control panel 32 and antenna 33 are located on the outside of the housing 5. The PLC module 31 is connected to the motor drive module 11, the 485 wireless transmitter module, and the 485 wireless receiver module. The industrial unit is connected to another 485 wireless transmitter module and another 485 wireless receiver module.

[0087] An operator port is provided on the outside of the housing 5; the operator can be connected to the operator port or connected wirelessly. Preferably, two wiring ports are provided below the control panel 32: one is a power supply port 34, responsible for powering the entire device, and the other is an operator interface 35, which allows control of the device via operator buttons. The rod-picking device control of this invention provides both wired and wireless operation modes. The panel antenna 33 provides wireless signal transmission and reception, and control can also be achieved directly via a wireless operator.

[0088] To prevent damage to the rod-retrieving device and ensure its safe operation, the encoder 42, torque sensor 41, and limit switch 43 together constitute the protection unit 4 of the rod-retrieving device. The protection principle is as follows: the encoder 42, torque sensor 41, and guide wheel 14 are mounted on the same rotating shaft. The rotational speed and force of the guide wheel are input to the PLC module 31 via the encoder 42 and torque sensor 41 to monitor the speed and friction of the gripper 23 during its vertical movement. When the movement speed or friction of the gripper 23 exceeds the set limit, the rod-retrieving device activates its protection action, preventing the gripper 23 from continuing to move. The limit switch 43, installed at the bottom of the housing 5, prevents the gripper 23 from being lifted too high, damaging the equipment and the fuel rod 6 to be replaced. When the top plane of the counterweight 21 makes contact with the contact point of the limit switch 43 extending outside the housing 5, triggering the limit switch 43, the motor 11 stops rising to prevent human error.

[0089] This invention presents a compact rod-retrieving device, with an overall assembly length of approximately 5 meters, solving the problem of height restrictions on equipment in nuclear fuel plant buildings. It also features a simple structure and stable mechanical performance. Utilizing mostly threaded connections, it allows for quick assembly and disassembly, facilitating hoisting and transportation. Operation is simple and requires minimal learning. It offers multiple operating modes, including wireless and wired remote control, allowing for flexible selection based on the site environment. The device incorporates multiple protection functions, such as load protection, limit switches, and travel protection, effectively ensuring safety during the rod-retrieving and maintenance process of nuclear fuel assemblies.

[0090] See Figure 13 One embodiment of the present invention discloses a rod-changing method, using the rod-taking device described in any of the above embodiments, comprising the following steps:

[0091] S10: Use an auxiliary hoist to lift the rod removal device and align it with the position of the fuel rod 6 to be replaced;

[0092] S20: Lower the auxiliary hoist and lift the main hoist, and vertically align the outer sleeve 25 with the guide hole on the guide plate corresponding to the position of the fuel rod 6 to be replaced;

[0093] S30: Start the power unit 1 to lower the core rod 22, gripper 23 and locking tube 24. Stop the operation of the power unit 1 when the locking tube 24 is exposed outside the outer tube 25 and close to the top of the end of the fuel rod 6 to be replaced.

[0094] S40: Rotate the locking tube 24 and move it along the core rod 22 in a direction away from the pawl 231, so that the pawl 231 opens;

[0095] S50: Continue to start the power unit 1 to lower the core rod 22, so that the pawl 231 surrounds the outer periphery of the end of the fuel rod 6 to be replaced and stop the power unit 1 from operating;

[0096] S60: The rotating locking tube 24 moves along the core rod 22 toward the direction of the pawl 231, and the pawl 231 is put into the locking tube 24 and closed to clamp the outer periphery of the end of the fuel rod 6 to be replaced;

[0097] S70: Start the power unit 1 to raise the core rod 22, the gripper 23 drives the fuel rod to be replaced 6 to rise, and stop the power unit 1 when the fuel rod to be replaced 6 is completely inside the outer tube 25.

[0098] S80: Lift the auxiliary hoist and move the rod removal device above the temporary storage container opening, and put the fuel rod 6 to be replaced into the temporary storage container;

[0099] S90: Use the rod-removing device to grab the stainless steel replacement rod and insert it back into the original position of the fuel rod 6 to be replaced. The rod replacement method of the present invention includes the rod-removing device described in any of the above embodiments, and will not be repeated here. Preferably, the housing 5 of the rod-removing device is also provided with lifting lugs, and the auxiliary lifting hook is connected to the lifting lugs of the housing 5, thereby lifting the entire rod-removing device.

[0100] The method for replacing fuel rods in this invention can extract defective fuel rods from a new fuel assembly and insert a stainless steel replacement rod into the original position of the defective fuel rod.

[0101] Specifically:

[0102] Step S90 includes: S91: Using the rod-grabbing device to grab the stainless steel replacement rod and starting the power unit 1 to raise the core rod 22, the gripper 23 drives the stainless steel replacement rod to rise, and the power unit 1 stops operating when the stainless steel replacement rod is completely inside the outer sleeve 25; S92: Using the auxiliary hoist to move the rod-grabbing device above the original position of the fuel rod 6 to be replaced; confirming that the trolley of the auxiliary hoist is accurately aligned; S93: Lowering the main lifting arm of the auxiliary hoist, vertically aligning the outer sleeve 25 and bringing it close to the original position of the fuel rod 6 to be replaced; S94: Starting the power unit 1 to lower the core rod 22, completely inserting the stainless steel replacement rod into the original position of the fuel rod 6 to be replaced. Preferably, the counterweight 21 is used to completely insert the stainless steel replacement rod into the original position of the fuel rod 6 to be replaced. In some other embodiments, other force-applying bodies can also be used to press down the stainless steel replacement rod.

[0103] During the rod replacement process, monitor the load changes in real time and stop the operation immediately if any abnormality occurs.

[0104] By using the technical solution described in this invention, the following beneficial effects can be achieved:

[0105] The rod extraction device described in this invention can extract defective fuel rods from new fuel assemblies.

[0106] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that for those skilled in the art, the above embodiments or technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present invention. These all fall within the protection scope of the present invention. That is, the embodiments described "in some embodiments" can be freely combined with any of the embodiments above and below. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A rod-picking device, characterized in that, It includes a housing (5), a power unit (1) and an execution unit (2) disposed within the housing (5), and a control unit (3) that is communicatively connected to the power unit (1); The execution unit (2) includes a core rod (22), a gripper (23), a locking tube (24), and an outer tube (25). The core rod (22), the gripper (23), and the locking tube (24) are disposed inside the outer tube (25) and can move along the axial direction of the outer tube (25). The locking tube (24) is sleeved on the core rod (22) and the gripper (23) and can move along the axial direction of the core rod (22). The two ends of the core rod (22) are respectively connected to the power unit (1) and the gripper (23). The end of the gripper (23) away from the core rod (22) is provided with a pawl (231) for gripping the fuel rod (6) to be replaced. The power unit (1) includes a motor (11), a drum (12) and a hoisting rope (13); the motor (11) is connected to the drum (12); the drum (12) is connected to the housing (5); the two ends of the hoisting rope (13) are connected to the drum (12) and the core rod (22) respectively; The execution unit (2) further includes a counterweight (21), which is sleeved on the outer sleeve (25) and can move along the axial direction of the outer sleeve (25); the hoisting rope (13) is connected to the core rod (22) through the counterweight; The counterweight (21) includes an annular component and a stiffening plate (211). The annular component is sleeved on the outer peripheral wall of the outer sleeve (25). The stiffening plate (211) passes through the annular component and the outer sleeve (25) in sequence along the radial direction of the annular component. The suspension rope (13) is connected to the core rod (22) through the counterweight. The outer sleeve (25) includes at least two strips with annular cross-sections. The at least two strips enclose the core rod (22), the clamp (23) and the locking tube (24) for passage. There is a strip channel between two adjacent strips. The strip channel extends axially. The two ends of the stiffener (211) pass through the strip channel and are connected to the annular strips.

2. The rod-taking device according to claim 1, characterized in that, The number of the suspension ropes (13) is at least two. The stiffening plate (211) is provided with a first through hole (212), at least two second through holes (213) and a first screw hole (214). The first through hole (212) extends along the axial direction of the outer sleeve (25) and is located close to the power unit (1). The first screw hole (214) is located away from the power unit (1) and is used to connect with the core rod (22). There is a gap between the first through hole (212) and the first screw hole (214). At least two second through holes (213) are respectively located on both sides of the gap, and the second through holes (213) extend along the axial direction perpendicular to the outer sleeve (25). One end of each of the suspension ropes (13) passes through the first through hole (212) and the corresponding second through hole (213) in sequence and then extends out of the stiffening plate (211); The counterweight (21) also includes a clamping cover (216), which is connected to the stiffening plate (211) and is used to clamp the end of each of the lifting ropes (13) that extends out of the stiffening plate (211).

3. The rod-taking device according to claim 2, characterized in that, The core rod (22) includes a body (224), a first threaded section (221), a second threaded section (222), and a third threaded section (223). The first threaded segment (221) is located at one end of the body part (224) and is inserted into the first threaded hole (214) for connection; the third threaded segment (223) is located at the other end of the body part (224) and is connected to the jaw (23); the second threaded segment (222) is located between the first threaded segment (221) and the third threaded segment (223) and is connected to the locking tube (24).

4. The rod-taking device according to any one of claims 1-3, characterized in that, The strip-shaped component includes an inner strip segment (251) and an outer strip segment (252). The outer strip segment (252) is disposed on the outer peripheral wall of the inner strip segment (251) and is connected to the inner strip segment (251).

5. The rod-taking device according to claim 4, characterized in that, The outer sleeve (25) also includes an upper end cap (253), a lower end cap (254), and at least two support rods (255). The upper end cap (253) is connected to and fixed to the end of the outer strip segment (252) near the power unit (1) by at least two of the outer strip segments (252). The upper end cap (253) is provided with a central through hole for the suspension rope (13) to pass through. The lower end cap (254) is connected to the end of the outer strip segment (252) away from the power unit (1) on one side and at least two of the outer strip segments (252) are fixed thereon. The other side of the lower end cap (254) is provided with a protective tube (256) through which the fuel rod (6) to be replaced passes. At least two of the support rods (255) are connected at one end to at least two of the outer strip segments (252), and the other end of the two support rods (255) are connected and fixed to the box body (5).

6. The rod-taking device according to any one of claims 1 to 3, characterized in that, The rod-picking device also includes a torque sensor (41) and an encoder (42); the power unit (1) also includes a guide wheel (14). The guide wheel (14) is located between the drum (12) and the outer tube (25); the hoisting rope (13) is wound around the guide wheel (14) and extends out to connect with the counterweight (21); One end of the torque sensor (41) is connected to the guide wheel (14), and the other end of the torque sensor (41) is connected to the encoder (42).

7. The rod-taking device according to any one of claims 1 to 3, characterized in that, The rod-retrieving device also includes a limiter (43); the limiter (43) is communicatively connected to the control unit (3), and the limiter (43) is partially located in the housing (5) near the counterweight (21). One end of the limiter (43)'s limiting piece (431) extends out of the housing (5) and is used to contact the counterweight (21) to trigger the action of the limiter (43).

8. The rod-taking device according to any one of claims 1 to 3, characterized in that, The control unit (3) includes a PLC module (31) for processing data and sending control signals, a motor (11) drive module for controlling the rotation direction and speed of the motor (11), an industrial machine for setting parameters, monitoring and processing data, a wireless transmission module and a wireless receiving module for establishing communication between the industrial machine and the PLC module (31), a control panel (32) for displaying and modifying parameters, a controller for controlling the operation of the motor (11), and an antenna (33) for providing wireless signal transmission and reception. The PLC module (31), the motor (11) drive module, the wireless transmission module and the wireless receiving module are all located inside the housing (5); the control panel (32) and the antenna (33) are located outside the housing (5); An operator port is provided on the outside of the housing (5); the operator is connected to the operator port or the operator uses a wireless connection.

9. A method for changing a rod, characterized in that, Using the rod-taking device according to any one of claims 1-8 includes the following steps: S10: Use an auxiliary hoist to lift the rod-retrieving device and align it with the position of the fuel rod (6) to be replaced; S20: Lower the auxiliary hoist main lifting mechanism and align the outer sleeve (25) vertically with the guide hole on the guide plate opposite the position of the fuel rod (6) to be replaced; S30: Start the power unit (1) to lower the core rod (22), gripper (23) and locking tube (24), and stop the operation of the power unit (1) when the locking tube (24) protrudes outside the outer tube (25) and approaches the end of the fuel rod (6) to be replaced; S40: Rotate the locking tube (24) along the core rod (22) in a direction away from the pawl (231) so that the pawl (231) opens; S50: Continue to start the power unit (1) to lower the core rod (22) so that the pawl (231) surrounds the end of the fuel rod (6) to be replaced and stop the operation of the power unit (1); S60: Rotate the locking tube (24) and move it along the core rod (22) toward the direction of the pawl (231). The pawl (231) is put into the locking tube (24) and closed and clamped on the outer periphery of the end of the fuel rod (6) to be replaced. S70: Start the power unit (1) to raise the core rod (22), the gripper (23) drives the fuel rod to be replaced (6) to rise, and stop the operation of the power unit (1) when the fuel rod to be replaced (6) is completely inside the outer tube (25); S80: Lift the auxiliary hoist and move the rod taking device above the temporary storage container opening, and put the fuel rod to be replaced (6) into the temporary storage container; S90: Use the rod-grabbing device to grab the stainless steel replacement rod and insert the stainless steel replacement rod back into the original position of the fuel rod (6) to be replaced.

10. The rod replacement method according to claim 9, characterized in that, Step S90 includes: S91: Use the rod-grabbing device to grab the stainless steel replacement rod and start the power unit (1) to raise the core rod (22). The gripper (23) drives the stainless steel replacement rod to rise. When the stainless steel replacement rod is completely inside the outer tube (25), stop the operation of the power unit (1). S92: Use the auxiliary hoist to move the rod-retrieving device above the original position of the fuel rod to be replaced (6); S93: Lower the auxiliary hoist main lifting mechanism to vertically align the outer sleeve (25) with and approach the original position of the fuel rod (6) to be replaced; S94: Start the power unit (1) to lower the core rod (22) and fully insert the stainless steel replacement rod into the original position of the fuel rod to be replaced (6).

Images