An online replacement device for a main bolt of a reactor coolant pump of a nuclear power plant

Abstract

This invention belongs to the field of nuclear power plant maintenance technology, specifically relating to an online replacement device for the main bolts of a nuclear power plant reactor coolant pump. In this device, an upper and lower ring rail are fixedly mounted on the main pump coupling; a robotic arm slides circumferentially on the lower ring rail; a balancer is mounted on the robotic arm base, and a movable pulley assembly is movably mounted on the robotic arm, connected to the balancer; a linear module slides radially on the robotic arm, and a hand-operated hoist A is mounted on the robotic arm, connected to the linear module; one end of the track is erected at the maintenance port, and the other end is supported on the ground outside the pump by outriggers; an external trolley slides on the track; a slewing bearing is mounted on the external trolley, a column is fixedly connected to the slewing bearing, and a cantilever is hinged to the column; one end of the hand-operated hoist B is mounted on the base plate of the external trolley. This invention enables quick replacement of the main bolt without removing the upper assembly of the main bolt.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power plant maintenance technology, specifically relating to an online replacement device for the main bolts of a nuclear power plant reactor coolant pump. Background Technology

[0002] The reactor coolant pump, also known as the main pump, is the only high-speed rotating device in the reactor coolant system. It is used to drive the high-temperature, high-pressure, and radioactive coolant, allowing the coolant to pass through the reactor core at a large flow rate, transferring the heat generated in the core to the steam generator. It is one of the most critical rotating machines in a nuclear power plant.

[0003] Currently, the maintenance logic for replacing main pump main bolts and conducting in-service inspections at various power plants is carried out along with the comprehensive hydraulic analysis of the main pump. Before disassembling the main bolts, the main pump motor bearing assembly, lower motor support, high-pressure cooler, and other auxiliary systems must be disassembled first. Therefore, the implementation window during the construction and installation phase is after the pre-service inspection and before motor installation. Missing this window will significantly impact the main project construction schedule and cost. If online replacement of the motor without disassembly cannot be implemented for operating units, it will significantly impact the main overhaul schedule and economic benefits.

[0004] For main bolts with unrestricted space and relatively light weight (less than 80kg), a customized winch is used for lifting and manual transport. For main bolts with restricted space (<30mm) and weight (>80kg), which cannot be directly transported manually, new technical solutions need to be developed to address a series of technical challenges related to bolt lifting and transport. Summary of the Invention

[0005] The purpose of this invention is to provide an online replacement device for the main bolts of reactor coolant pumps in nuclear power plants. This device enables online replacement of the main pump main bolts, allowing for quick replacement without removing the upper components of the main bolts, and effectively solving technical problems such as the introduction and removal of heavy main bolts in confined spaces.

[0006] Technical solution to achieve the purpose of this invention:

[0007] An online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant, the device comprising a robotic arm installed inside the pump and an external transfer device;

[0008] The pump-mounted robotic arm includes: an upper ring rail, a lower ring rail, the robotic arm, a linear module, a hand-operated hoist A, a movable pulley assembly, and a balancer. The upper and lower ring rails are fixedly mounted on the main pump coupling. The robotic arm slides circumferentially on the lower ring rail. The balancer is mounted on the robotic arm base, and the movable pulley assembly is movably mounted on the robotic arm, connected to the balancer. The linear module includes a fixed pulley assembly and a U-shaped bracket. The U-shaped bracket slides radially on the robotic arm, and the fixed pulley assembly is mounted on the U-shaped bracket. The hand-operated hoist A is mounted on the robotic arm, connected to the fixed pulley assembly. Main bolts are installed via the movable and fixed pulley assemblies.

[0009] The external transfer device for the pump includes: a track, a hand-operated hoist B, outriggers, a cantilever, a column, a slewing bearing, and an external trolley. One end of the track is installed at the maintenance port, and the other end is supported on the ground outside the pump by the outriggers. The external trolley is slidably installed on the track. The slewing bearing is installed on the external trolley, the column is fixedly connected to the slewing bearing, the cantilever is hinged to the column, and the main bolt is installed on the cantilever. One end of the hand-operated hoist B is installed on the base plate of the external trolley, and the other end is connected to the main bolt.

[0010] The device also includes a clamp. When the main bolt is moved inside the pump, the main bolt is connected to the fixed pulley assembly through the clamp. When the main bolt is moved outside the pump, the main bolt is installed on the cantilever through the clamp.

[0011] The clamp includes: a left clamp, a right clamp, a connecting shaft, a locking pin, and a nut; the left clamp and the right clamp are semi-circular structures, one end of the left clamp and the right clamp are hinged through the connecting shaft, and the other end is connected by the locking pin, and the locking pin is locked by the nut.

[0012] The clamp also includes a nylon pad, with nylon pads provided on the inner sides of the left and right clamps.

[0013] The linear module also includes a sliding connecting rod, which is slidably mounted on the U-shaped bracket in the vertical direction.

[0014] The robotic arm installed inside the pump also includes: a steel wire rope B and a steel wire rope C. The first end of steel wire rope C is fixedly connected to the center of the sliding connecting rod, and the second end is connected to the hand-operated hoist A. Steel wire rope B is wound around the fixed pulley assembly, with its first end fixedly connected to the upper end of the sliding connecting rod 20 and its second end connected to the eye bolt B, which is connected to the main bolt.

[0015] The pump-mounted robotic arm also includes: a movable crossbeam, which is movably mounted on the robotic arm, and a movable pulley assembly mounted on the movable crossbeam.

[0016] The movable crossbeam is movably mounted on the robotic arm via a rotary plunger A, enabling quick assembly and disassembly of the movable crossbeam and the robotic arm.

[0017] The robotic arm installed inside the pump also includes: a steel wire rope A9, one end of which is connected to the balancer, and then wound around the movable pulley assembly in sequence, with the end fixedly connected to the movable crossbeam.

[0018] The lower end of the movable pulley assembly is connected to an eye bolt C, which is connected to the main bolt.

[0019] The robotic arm installed inside the pump also includes: a ring rail slider and a linear slider; a ring rail slider is provided on the lower ring rail, the robotic arm base is fixedly connected to the ring rail slider, and the robotic arm is slidably installed on the lower ring rail through the ring rail slider; the U-shaped bracket is slidably installed on the linear guide rail of the robotic arm through the linear slider.

[0020] The external transfer device for the pump also includes an adjusting stud. One end of the cantilever is hinged to the column, and the middle is connected to the column through the adjusting stud. By turning the adjusting stud, the cantilever can be rotated up and down around the hinge axis.

[0021] The external transfer device also includes a rotary plunger B, which is mounted on the external trolley. When the rotary plunger B is inserted into the positioning hole on the slewing bearing and the external trolley, the column position is locked.

[0022] The external transfer device also includes limit blocks, with limit blocks at both ends of the track to prevent the external trolley from derailing during operation.

[0023] The external transfer device for the pump also includes a pressure plate. The pressure plate is provided on the cantilever, and the main bolt is fixed to the cantilever by the pressure plate.

[0024] The external pump transfer device also includes a foot pedal, with a foot pedal between the outriggers and the rail, providing a standing platform for maintenance personnel to operate.

[0025] The beneficial technical effects of this invention are as follows:

[0026] 1. The present invention provides an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant. By installing a robotic arm inside the pump, the main bolt can move in vertical, radial, and circumferential degrees of freedom.

[0027] 2. This invention provides an online replacement device for the main bolts of a reactor coolant pump in a nuclear power plant. Through the combined application of a balancer and a moving pulley assembly, and the combined application of a fixed pulley assembly and a hand-operated hoist, the device meets the lifting and lowering requirements of the main bolts within the pump. By changing the models of the balancer, pulley assembly, and hand-operated hoist, the device can meet the lifting and lowering needs of heavy bolts (up to 500 kg) under different operating conditions.

[0028] 3. The present invention provides an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant. By setting a balancer, the residual weight of the bolt can be reduced, making it easier to tighten the bolt.

[0029] 4. The present invention provides an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant. By setting an external transfer device, the main bolt can achieve four degrees of freedom of movement, including horizontal movement, circumferential rotation, and two types of axial flipping, ensuring that the main bolt can be smoothly introduced into and out of the narrow space inside the pump.

[0030] 5. This invention provides an online replacement device for the main bolts of a nuclear power plant reactor coolant pump. The entire system adopts a high-strength, lightweight design, with the largest single component weighing less than 20 kg. The connections between components utilize quick-release designs such as knob plungers and locking pins, facilitating maintenance operations. Its advantages are particularly evident in harsh environments such as those with radioactive content where extended working hours are critical. Attached Figure Description

[0031] Figure 1 A schematic diagram of the mechanical arm structure installed inside the pump in an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant, provided by the present invention.

[0032] Figure 2 A schematic diagram of the working state of the robotic arm installed inside the pump in an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant, provided by the present invention.

[0033] Figure 3 Left view of the robotic arm installed inside the pump in an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant, provided by the present invention;

[0034] Figure 4 A schematic diagram of the moving pulley assembly in an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant, provided by the present invention;

[0035] Figure 5 A schematic diagram of the external transfer device in an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant, provided by the present invention;

[0036] Figure 6 This is a schematic diagram of the clamp structure in an online replacement device for the main bolt of a nuclear power plant reactor coolant pump provided by the present invention.

[0037] In the diagram: 1-Upper ring rail; 2-Lower ring rail; 3-Ring rail slider; 4-Mechanical arm; 5-Eye contact screw A; 6-Linear guide rail; 7-Balancer; 8-Linear slider; 9-Wire rope A; 10-Moving crossbeam; 11-Knob plunger A; 12-Fixed pulley assembly; 13-Wire rope B; 14-Hand chain hoist A; 15-Eye contact screw B; 16-Clamp; 17-Moving pulley assembly; 18-Eye contact screw C; 19-Wire rope C; 20-Sliding... 21-Moving connecting rod; 22-U-shaped bracket; 23-Fixing block; 24-Limiting block; 25-Hand chain hoist B; 26-Pedal; 27-Outrigger; 28-Pressure plate; 29-Cantilever; 30-Adjusting stud; 31-Column; 32-Slewing bearing; 33-Pump external trolley; 34-Knob plunger B; 35-Clamp; 36-Left clamp; 37-Right clamp; 38-Connecting shaft; 39-Nylon pad; 40-Locking pin; 41-Nut. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0039] The present invention provides an online replacement device for the main bolt of a reactor coolant pump in a nuclear power plant, comprising a robotic arm installed inside the pump and a transfer device outside the pump.

[0040] A robotic arm is installed inside the pump to move the main bolt up and down within the pump chamber. For example... Figure 1-3 As shown, the robotic arm installed inside the pump includes: upper ring rail 1, lower ring rail 2, ring rail slider 3, robotic arm 4, eye bolt A5, linear guide rail 6, balancer 7, linear slider 8, wire rope A9, movable crossbeam 10, knob plunger A11, fixed pulley assembly 12, wire rope B13, hand chain hoist A14, eye bolt B15, clamp 16, movable pulley assembly 17, eye bolt C18, wire rope C19, sliding connecting rod 20, and U-shaped bracket 21.

[0041] The upper ring rail 1 and lower ring rail 2 are fixedly installed on the main pump coupling bolts (the objects to be inspected, not part of this invention), providing support for other components mounted on the robotic arm inside the pump. The lower ring rail 2 has a ring rail slider 3, which can support other components to move circumferentially along the arc guide rail. The base of the robotic arm 4 is fixedly connected to the ring rail slider 3, and the robotic arm 4 is circumferentially slidably mounted on the lower ring rail 2 via the ring rail slider 3. The inner circle of the upper ring rail 1 provides support and guidance for the circumferential movement of the robotic arm 4. The robotic arm 4 is a structural component used to assist in the installation, disassembly, and internal transfer of the main bolt. The balancer 7 is installed on the base of the robotic arm 4, and the movable pulley assembly 17 is movably installed on the robotic arm 4, connected to the balancer 7. The balancer 7 can balance the weight of the main bolt during installation and disassembly, reducing the frictional resistance caused by its own weight when tightening the main bolt. The movable pulley assembly 17 can further amplify the balancing force of the balancer 7, facilitating the operator's installation and disassembly of the main bolt. The linear module can slide along the linear guide rail 6 on the robotic arm 4 to adjust to the desired radial working position. The linear module includes: a linear slider 8, a fixed pulley assembly 12, a U-shaped bracket 21, and a sliding connecting rod 20. Due to structural limitations, the lifting height of the movable pulley assembly 17 is limited. When the main bolt is lifted to a certain height, the fixed pulley assembly 12 and clamp 16 can be switched to lift the main bolt as needed. The clamp 16 adopts a specially designed Half structure, including a left clamp 36, a right clamp 37, a connecting shaft 38, a nylon pad 39, a locking pin 40, and a nut 41. The height of the main bolt is changed by controlling the winding and unwinding of the wire rope of the fixed pulley assembly 12 through the hand chain hoist A14.

[0042] like Figure 1 As shown, a ring rail slider 3 is pre-installed on the lower ring rail 2, and the split-design lower ring rail 2 is installed onto the main pump coupling bolt. The split-design upper ring rail 1 is then installed onto the main pump coupling bolt. The base of the robotic arm 4 is fixedly connected to the ring rail slider 3 with fasteners, and the robotic arm 4 is circumferentially slidably mounted on the lower ring rail 2 via the ring rail slider 3.

[0043] like Figure 1 As shown, the robotic arm 4 is equipped with a linear guide rail 6, on which the linear module is mounted. The linear module includes a linear slider 8, a fixed pulley assembly 12, a sliding connecting rod 20, and a U-shaped bracket 21. The U-shaped bracket 21 is slidably mounted on the linear guide rail 6 of the robotic arm 4 via the linear slider 8. The U-shaped bracket 21 can slide radially on the linear guide rail 6. The sliding connecting rod 20 is slidably mounted on the U-shaped bracket 21 in the vertical direction. The fixed pulley assembly 12 is mounted on the U-shaped bracket 21. A hand-operated hoist A14 is hung on the robotic arm 4.

[0044] like Figure 3As shown, the first end of wire rope C19 is fixedly connected to the center of sliding connecting rod 20, adjusted to a suitable length, guided by the pulley on U-shaped bracket 21, and the end is connected to hand chain hoist A14. Two wire ropes B13 are wound around the fixed pulley assembly 12, the first end is fixedly connected to the upper end of sliding connecting rod 20, adjusted to a suitable length, and the end is connected to eye bolt B15.

[0045] like Figure 1 , Figure 4 As shown, the movable crossbeam 10 is movably mounted on the robotic arm 4, and the movable pulley assembly 17 is mounted on the movable crossbeam 10 by fasteners. The lower part of the movable pulley assembly 17 is fitted with an eye bolt C18, the size of which can be adapted to the process screw hole at the top of the main bolt to be disassembled. The movable crossbeam 10 can be quickly attached to and detached from the robotic arm 4 via a rotary plunger A11.

[0046] like Figure 1 As shown, an eye bolt A5 is installed on the screw hole of the base of the robotic arm 4, and the spring balancer 7 is hung on the eye bolt A5. The spring balancer 7 has a built-in steel wire rope A9. The steel wire rope A9 of the spring balancer 7 is pulled out and wound around the movable pulley assembly 17 in sequence, with the end fixedly connected to the movable crossbeam 10.

[0047] The external pump transfer device is used to transfer the main bolts and nuts as a whole through the main pump inspection hole, allowing for transfer between the inside and outside of the main pump. For example... Figure 5 As shown, the external transfer device for the pump includes a fixed block 22, a limiting block 23, a track 24, a hand-operated hoist B25, a pedal 26, a support leg 27, a pressure plate 28, a cantilever 29, an adjusting stud 30, a column 31, a slewing bearing 32, an external trolley 33, and a knob plunger B34.

[0048] The track 24 is customized according to the working environment and dimensions, guiding the movement of the external pump trolley 33 and providing support for the entire unit's operation outside the pump. The entire external pump transfer device is designed to balance strength and ease of transport, with a maximum single-piece weight of less than 20 kg. Limit blocks 23 are provided at both ends of the track 24 to prevent the external pump trolley 33 from derailing during operation. A footboard 26 is provided between the outriggers 27 and the track 24, providing a standing platform for maintenance personnel. The external pump trolley 33, as the main load-bearing component, can move horizontally along the track 24. The cantilever 29 on the external pump trolley 33 can rotate horizontally via the slewing bearing 32. The rotating plunger B34 has a limiting function; when it is screwed in, the circumferential position of the external pump trolley 33 is locked. One end of the cantilever 29 is hinged to the column 31; the cantilever 29 can be rotated up and down around the hinge axis by adjusting the stud 30. A hand chain hoist B25 is installed on the base plate of the pump trolley 33. The other end of the hand chain hoist B25 is connected to the main bolt. Adjusting the chain length between the hand chain hoist B25 and the main bolt can change the posture of the main bolt, thereby completing the transfer through the inspection hole connecting the inside and outside of the pump.

[0049] like Figure 5 As shown, one end of the track 24 is mounted at the maintenance port via a fixing block 22, and the other end of the track 24 is supported on the ground outside the pump via a support leg 27. A limiting block 23 is fixed on the track 24, and a pedal 26 is installed between the support leg 27 and the track 24. The external trolley 33 is located between two symmetrical tracks 24 and is slidably mounted on the tracks 24.

[0050] like Figure 5 As shown, the slewing bearing 32 and the rotating plunger B34 are mounted on the external trolley 33 using fasteners. The column 31 is fixedly connected to the slewing bearing 32 using fasteners. The knob plunger B34 acts as an anti-rotation pin; when the knob plunger B34 is inserted into the positioning holes on the slewing bearing 32 and the external trolley 33, the position of the column 31 is locked. One end of the cantilever 29 is hinged to the column 31, and the middle is connected to the column 31 via an adjusting stud 30. By turning the adjusting stud 30, the cantilever 29 can be rotated up and down around the hinge axis.

[0051] like Figure 6 As shown, clamp 16 includes a left clamp 36, a right clamp 37, a connecting shaft 38, a nylon pad 39, a locking pin 40, and a nut 41. The left clamp 36 and right clamp 37 are hinged together at one end via the connecting shaft 38, and the other end is connected via the locking pin 40 to allow for quick opening and closing of the clamps. The nut 41 is used to lock the locking pin 40. Nylon pads 39 are laid on the inner sides of the left clamp 36 and right clamp 37 to prevent damage to the main bolt. Two symmetrical rotating shafts on clamp 16 have threaded holes. When the main bolt is moved inside the pump, it can be connected to the eye bolt B15 through the threaded holes. When the main bolt is moved outside the pump, it is installed on the cantilever 29 through the threaded holes. A pressure plate 28 is provided on the cantilever 29 to fix the main bolt to the cantilever 29.

[0052] The online replacement device for the main bolt of a nuclear power plant reactor coolant pump, provided by this invention, mainly includes the following steps for removing the main bolt from inside the pump and transferring it outside:

[0053] Step 1: Rotate the robotic arm 4 around the lower ring rail 2 to above the main bolt to be disassembled, connect the eye bolt C18 at the lower end of the movable pulley assembly 17 to the main bolt, and slowly adjust the wire rope A9 of the spring balancer 7 to the tensioned state so that the weight of the main bolt to be disassembled is borne by the movable pulley assembly 17, the spring balancer 7 and the robotic arm 4.

[0054] Step 2: After unscrewing the main bolt, lift it to a suitable height using wire rope A9. Install clamp 16 at the bottom of the main bolt, connect clamp 16 to eye bolt B15, and then disconnect the main bolt from eye bolt C18. The weight of the main bolt is borne by fixed pulley assembly 12 and robotic arm 4.

[0055] Step 3: Using the hand-operated hoist A14, sequentially pull the wire rope C19, sliding connecting rod 20, wire rope B13, eye bolt B15, and clamp 16 to raise the main bolt to the appropriate height.

[0056] Step 4: Push the external trolley 33 into the pump chamber so that the clamp 16 falls on the cantilever 29. Use the hand-operated hoist A14 to lower the height of the main bolt so that the weight of the main bolt is borne by the cantilever 29 and the external trolley 33. Use the pressure plate 28 to fix the clamp 16 and the main bolt.

[0057] Step 5: Install one end of the hand chain hoist B25 onto the base plate of the column 31, and connect the other end to the head of the main bolt.

[0058] Step 6: Adjust the trolley 33 outside the pump to change its position on the track 24, adjust the distance between the hand chain hoist B25 and the head of the main bolt to change the elevation angle of the main bolt, and adjust the length of the stud 30 to change the horizontality of the cantilever 29, so as to realize the spatial position and posture change of the main bolt until the whole thing is transported out of the pump chamber.

[0059] Step 7: Slide the pump trolley 33 outward on track 24 and rotate the cantilever 29 to transfer the main bolt to the required position.

[0060] The steps of transferring the main bolt from outside the pump and installing it inside the pump using the online replacement device for the main bolt of the reactor coolant pump provided by this invention are the reverse of the steps above.

[0061] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. All contents not described in detail in the present invention can be derived from existing technologies.

Claims

1. An online replacement device for the main bolts of a reactor coolant pump in a nuclear power plant, characterized in that, The device includes a robotic arm installed inside the pump and a transfer device outside the pump; The pump-mounted robotic arm includes: an upper ring rail (1), a lower ring rail (2), a robotic arm (4), a linear module, a hand-operated hoist A (14), a movable pulley assembly (17), and a balancer (7); the upper ring rail (1) and the lower ring rail (2) are fixedly mounted on the main pump coupling; the robotic arm (4) is circumferentially slidably mounted on the lower ring rail (2); the balancer (7) is mounted on the base of the robotic arm (4), and the movable pulley assembly (17) is movably mounted on the robotic arm (4). (17) Connected to the balancer (7); The linear module includes a fixed pulley assembly (12) and a U-shaped bracket (21). The U-shaped bracket (21) is slidably mounted on the robotic arm (4) in the radial direction. The fixed pulley assembly (12) is mounted on the U-shaped bracket (21). The hand chain hoist A (14) is mounted on the robotic arm (4). The fixed pulley assembly (12) is connected to the hand chain hoist A (14). The main bolts are installed through the movable pulley assembly (17) and the fixed pulley assembly (12) respectively. The external transfer device includes: a track (24), a hand-operated hoist B (25), a support leg (27), a cantilever (29), a column (31), a slewing bearing (32), and an external trolley (33); one end of the track (24) is erected at the maintenance port, and the other end is supported on the ground outside the pump by the support leg (27); the external trolley (33) is slidably installed on the track (24); the slewing bearing (32) is installed on the external trolley (33), the column (31) is fixedly connected to the slewing bearing (32), the cantilever (29) is hinged to the column (31), and the main bolt is installed on the cantilever (29); one end of the hand-operated hoist B (25) is installed on the base plate of the external trolley (33), and the other end is connected to the main bolt.

2. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The device also includes a clamp (16). When the main bolt is moved inside the pump, the main bolt is connected to the fixed pulley assembly (12) through the clamp (16). When the main bolt is moved outside the pump, the main bolt is installed on the cantilever (29) through the clamp (16).

3. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 2, characterized in that, The clamp (16) includes: a left clamp (36), a right clamp (37), a connecting shaft (38), a locking pin (40), and a nut (41); the left clamp (36) and the right clamp (37) are semi-circular structures. One end of the left clamp (36) and the right clamp (37) are hinged through the connecting shaft (38), and the other end is connected by the locking pin (40). The locking pin (40) is locked by the nut (41).

4. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 3, characterized in that, The clamp (16) also includes a nylon pad (39), with the nylon pad (39) provided on the inner side of the left clamp (36) and the right clamp (37).

5. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The linear module also includes a sliding connecting rod (20), which is slidably mounted on the U-shaped bracket (21) in the vertical direction.

6. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 5, characterized in that, The mechanical arm installed inside the pump also includes: a steel wire rope B (13) and a steel wire rope C (19). The first end of the steel wire rope C (19) is fixedly connected to the center of the sliding connecting rod (20), and the end is connected to the hand-operated hoist A (14). The steel wire rope B (13) is wound on the fixed pulley assembly (12), the first end is fixedly connected to the upper end of the sliding connecting rod 20, and the end is connected to the eye bolt B (15). The main bolt is connected through the eye bolt B (15).

7. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The pump-mounted robotic arm also includes: a movable crossbeam (10), which is movably mounted on the robotic arm (4), and a movable pulley assembly (17) mounted on the movable crossbeam (10).

8. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 7, characterized in that, The movable crossbeam (10) is movably mounted on the robotic arm (4) via a rotary plunger A (11), enabling quick assembly and disassembly of the movable crossbeam (10) and the robotic arm (4).

9. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 7, characterized in that, The mechanical arm installed inside the pump also includes: a steel wire rope A9, one end of which is connected to the balancer (7), and then wound around the movable pulley assembly (17) in sequence, with the end fixedly connected to the movable crossbeam (10).

10. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The lower end of the movable pulley assembly (17) is connected to an eye bolt C (18), which is connected to the main bolt.

11. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The pump-mounted robotic arm also includes: a ring rail slider (3) and a linear slider (8); the lower ring rail (2) is provided with a ring rail slider (3), the base of the robotic arm (4) is fixedly connected to the ring rail slider (3), and the robotic arm (4) is slidably mounted on the lower ring rail (2) through the ring rail slider (3); the U-shaped bracket (21) is slidably mounted on the linear guide rail (6) of the robotic arm (4) through the linear slider (8).

12. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The external transfer device of the pump also includes an adjusting stud (30). One end of the cantilever (29) is hinged to the column (31), and the middle is connected to the column (31) through the adjusting stud (30). By turning the adjusting stud (30), the cantilever (29) can be rotated up and down around the hinge axis.

13. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The external transfer device also includes a rotary plunger B (34), which is installed on the external trolley (33). When the rotary plunger B (34) is inserted into the positioning hole on the slewing bearing (32) and the external trolley (33), the position of the column (31) is locked.

14. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The external transfer device also includes a limiting block (23), and the two ends of the track (24) are provided with limiting blocks (23) to prevent the external trolley (33) from derailing during operation.

15. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The external transfer device of the pump also includes a pressure plate (28). The pressure plate (28) is provided on the cantilever (29), and the main bolt is fixed on the cantilever (29) by the pressure plate (28).

16. The online replacement device for the main bolt of a nuclear power plant reactor coolant pump according to claim 1, characterized in that, The external transfer device for the pump also includes a footboard (26), with a footboard (26) provided between the outrigger (27) and the rail (24) to provide a standing platform for maintenance personnel.

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