Special device for disassembling and assembling sodium-cooled fast reactor core flowmeter and using method of special device

Abstract

The invention discloses a device special for disassembling and assembling a sodium-cooled fast reactor core flowmeter and a using method thereof.The device comprises an outer cylinder, the interior of the outer cylinder is hollow, the bottom of the outer cylinder is fixedly connected with an adjusting cylinder, the bottom of the adjusting cylinder is fixedly connected with a supporting seat, and the top of the outer cylinder is provided with a hoisting structure; the hoisting structures are mutually connected through the connecting assemblies, and the hoisting structures can drive the sodium-cooled fast reactor core flow meter to vertically lift in the outer cylinder, the adjusting cylinder and the supporting seat through the connecting assemblies. The sodium-cooled fast reactor core flowmeter is hoisted, loaded and unloaded in an automatic hoisting mode, the loading and unloading safety of the sodium-cooled fast reactor core flowmeter can be greatly improved, the installation of the sodium-cooled fast reactor core flowmeter is more flexible, adjustment can be conducted according to the actual site situation, the installation difficulty and cost are reduced, and the installation efficiency is improved. And intelligent hoisting is adopted, so that the hoisting process is safer.

Description

Technical Field

[0001] The invention relates to the technical field of disassembly and assembly of a core flowmeter of a sodium-cooled fast reactor, and in particular to a special device for disassembly and assembly of a core flowmeter of a sodium-cooled fast reactor and a use method thereof. Background Art

[0002] The sodium-cooled fast reactor core flowmeter, especially the permanent magnet pipeline sodium-cooled fast reactor core flowmeter, is a device specially used to measure the sodium flow in the pipeline. The permanent magnet pipeline sodium-cooled fast reactor core flowmeter works based on the principle of Faraday's law of electromagnetic induction. When liquid sodium flows in a sodium pipeline perpendicular to the magnetic field, it cuts the magnetic lines of force, thereby generating an induced electromotive force on two electrodes that are perpendicular to the direction of sodium movement and the direction of the magnetic lines of force. This induced electromotive force is proportional to the flow rate of sodium, and can be used to calculate the volume flow rate of sodium.

[0003] The existing sodium-cooled fast reactor core flowmeter is mainly disassembled by manual disassembly and assembly. The installation space of the sodium-cooled fast reactor core flowmeter is limited, such as compact pipeline layout and small space, which greatly increases the difficulty and risk of disassembly and assembly of the sodium-cooled fast reactor core flowmeter. In addition, liquid sodium is easy to form aerosol with a dose under high temperature, which is harmful to human inhalation, so sealing operation is required.

[0004] Therefore, it is necessary to design and create a special device for disassembling and assembling a core flow meter of a sodium-cooled fast reactor and a method for using the device. Summary of the invention

[0005] In order to solve the problems raised in the above-mentioned background technology, the purpose of the present invention is to provide a special device for disassembling and assembling a sodium-cooled fast reactor core flowmeter and a method for using the same, which has the advantage of being easy to disassemble and assemble the sodium-cooled fast reactor core flowmeter, and solves the problem that the sodium-cooled fast reactor core flowmeter is mainly disassembled by manual disassembly and assembly, and the installation space of the sodium-cooled fast reactor core flowmeter is limited, such as compact pipeline layout and small space, which greatly increases the difficulty and risk of disassembling and assembling the sodium-cooled fast reactor core flowmeter, and sodium itself has certain corrosiveness, which can easily cause personal injury to the operator.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solutions: a special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor and a method for using the same, comprising an outer cylinder; The interior of the outer cylinder is arranged to be hollow, an adjusting cylinder is fixedly connected to the bottom of the outer cylinder, a supporting seat is fixedly connected to the bottom of the adjusting cylinder, a hoisting structure is arranged on the top of the outer cylinder, a sodium-cooled fast reactor core flowmeter is arranged inside the outer cylinder, the sodium-cooled fast reactor core flowmeter and the hoisting structure are connected to each other through a connecting assembly, the hoisting structure can drive the sodium-cooled fast reactor core flowmeter to vertically rise and fall inside the outer cylinder, the adjusting cylinder and the supporting seat through the connecting assembly, an exhaust pipe is connected to the top of the right side of the outer cylinder, and a pressure maintaining structure surrounding the surface of the sodium-cooled fast reactor core flowmeter is arranged inside the outer cylinder.

[0007] As a preferred embodiment of the present invention, the lifting structure includes a winch fixedly connected to the top of the outer cylinder, a steel cable is wound on the surface of the winch, the steel cable extends to the inside of the outer cylinder from the side away from the winch and is interconnected with the connecting assembly, a bearing support pressure bracket is fixedly connected to the top of the outer cylinder, the bearing support pressure bracket is sleeved on the surface of the output end of the winch, and a weighing module is arranged at the bottom of the bearing support pressure bracket, and the weighing module can measure the lifting load-bearing weight of the winch.

[0008] As a preferred embodiment of the present invention, the connecting assembly includes a connecting long tube slidably connected to the inside of the outer tube, the bottom of the connecting long tube is fixedly connected to a connecting flange, the bottom of the connecting flange is interconnected with the top of the sodium-cooled fast reactor core flowmeter, the top of the connecting long tube is fixedly connected to a counterweight chain, the top of the counterweight chain is fixedly connected to a movable pulley block, and the top of the movable pulley block is fixedly connected to the bottom of the steel cable.

[0009] As a preferred embodiment of the present invention, the pressure maintaining structure includes a D-shaped cylinder connected to the surface of the outer cylinder, the number of the D-shaped cylinders is two and they are stacked on each other, the right sides of the two D-shaped cylinders are connected to an inflation valve, the interior of the D-shaped cylinder is fixedly connected to a flip shaft, the surface of the flip shaft is sleeved with a sealing pressure plate, and the outer surface of the sealing pressure plate can contact the inner wall of the D-shaped cylinder.

[0010] As a preferred embodiment of the present invention, a flange-fixed observation window is provided on the surface of the connecting long tube, and a sealing observation window corresponding to the sealing pressure plate is connected to the surface of the outer tube.

[0011] As a preferred embodiment of the present invention, the left side of the D-shaped cylinder is threadedly connected with a pressure plate pin, the right end of the pressure plate pin passes through the outer cylinder and extends to the top of the sealing pressure plate, and the surface of the D-shaped cylinder is connected to a spare inflation hole located at the top of the pressure plate pin.

[0012] As a preferred embodiment of the present invention, a plurality of sight glasses are connected to the surface of the adjusting cylinder, an adjusting rod is arranged around the outer surface of the adjusting cylinder, one end of the adjusting rod close to the adjusting cylinder passes through the adjusting cylinder and extends to the interior of the adjusting cylinder, the adjusting rod is threadedly connected to the adjusting cylinder, and the inner end of the adjusting rod can contact the surface of the sodium-cooled fast reactor core flowmeter.

[0013] A special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor and a method for using the same, comprising the following steps: S1: Use the hoist to move the outer cylinder to the top of the sodium-cooled fast reactor core flowmeter, and the winch releases the steel cable, so that the steel cable carries the connecting long cylinder downward by the movable pulley block. When the connecting long cylinder moves to the top of the sodium-cooled fast reactor core flowmeter, the connecting long cylinder is connected to the sodium-cooled fast reactor core flowmeter by the connecting flange. When the two are connected, start the winch in the reverse direction, the winch reels the steel cable and pulls the sodium-cooled fast reactor core flowmeter vertically up by the connecting long cylinder, so that the sodium-cooled fast reactor core flowmeter is completely moved to the inside of the outer cylinder and located on the top of the sealing plate; S2: Rotate the sealing pressure plate with the turning axis as the axis. When the outer surface of the sealing pressure plate contacts the inner wall of the outer cylinder and the outer cylinder is divided and sealed, gas is injected into the inner part of the outer cylinder through the inflation valve to maintain a certain gas pressure inside the outer cylinder. S3: When the internal air pressure of the outer cylinder is consistent with the external ambient air pressure, the regulating cylinder and the support seat are fixedly installed at the bottom of the outer cylinder, and then the outer cylinder together with the support seat are hoisted to the top of the flow meter installation hole and the support seat is connected to the device with a threaded assembly; S4: When the two are connected, the sealing plate is opened, and part of the argon gas inside the outer cylinder is replaced with the gas inside the device to keep the internal pressure of the outer cylinder consistent with that of the device. When the replacement is completed, the sodium-cooled fast reactor core flowmeter is slowly lowered by a winch. When the sodium-cooled fast reactor core flowmeter is stuck, the weight value of the weighing module decreases, and the system stops. The offset condition is observed by adjusting the sight glass on the surface of the cylinder and the adjustment rod on the surface of the cylinder is used to squeeze the sodium-cooled fast reactor core flowmeter for displacement. After adjusting the centering, it continues to descend until it is in place. S5: Loosen the connection between the adjusting tube and the supporting seat, continue to lower the steel cable to the set length, and then slowly lift the device so that the user can remove the connecting bolts between the connecting long tube and the sodium-cooled fast reactor core flowmeter. When the connecting long tube and the sodium-cooled fast reactor core flowmeter are disconnected, recycle the connecting long tube into the outer tube, thereby completing the disassembly and assembly of the sodium-cooled fast reactor core flowmeter.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention lifts and loads the sodium-cooled fast reactor core flowmeter by automatic lifting, which can greatly improve the loading and unloading safety of the sodium-cooled fast reactor core flowmeter, making the installation of the sodium-cooled fast reactor core flowmeter more flexible, and can be adjusted according to actual on-site conditions, reducing installation difficulty and cost. The use of vertical lifting helps to make the sensor lining wear evenly and extend its service life.

[0015] 2. When the dedicated device for the core flowmeter of a sodium-cooled fast reactor of the present invention is removed, the pressure-maintaining structures can be opened and closed respectively to reduce the risk of sodium leakage.

[0016] 3. The present invention provides a sealing observation window and a flange fixing observation window on the surface of the outer cylinder, so that the installation status of the sealing pressure plate and the flange can be viewed.

[0017] 4. The present invention provides an adjustment cylinder, which can use special tools to solve the problem of jamming or obstruction during lifting, so that the flow meter can be pushed to correct under the condition of argon pressure maintenance. At the same time, in order to make its operation accurate and fast, a sight glass is installed at the best viewing angle.

[0018] 5. The present invention can ensure that the steel wire rope is in a stretched state and prevent the steel wire rope from twisting by providing a movable pulley block and a connecting structure.

[0019] 6. The present invention installs a counterweight chain to keep the movable pulley block and the structural connecting member in a certain state without twisting, and installs a limiting roller to keep the movable pulley block and the structural connecting member in the center of the inner wall of the cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic cross-sectional view of the main structure of the present invention; Figure 3 It is a cross-sectional schematic diagram of the main structure of the present invention in a hoisting state; Figure 4 It is a schematic cross-sectional view of the local structure of the present invention.

[0021] In the figure: 1. outer cylinder; 2. adjusting cylinder; 3. supporting seat; 4. lifting structure; 5. core flowmeter of sodium-cooled fast reactor; 6. exhaust pipe; 7. pressure-maintaining structure a; 8. winch; 9. steel cable; 10. bearing support pressure bracket; 11. weighing module; 12. connecting long cylinder; 13. roller; 14. connecting flange; 15. counterweight chain; 16. movable pulley block; 17. inflation valve; 18. turning axis a; 19. sealing pressure plate a; 20. flange fixed observation window; 21. sealing observation window; 22. pressure plate pin; 23. spare inflation hole; 24. sight glass; 25. adjusting rod; 26. D-shaped cylinder a; 27. D-shaped cylinder b; 28. sealing pressure plate b; 29. ​​pressure-maintaining structure b; 30. turning axis b. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] like Figures 1 to 4 As shown, the present invention provides a special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor and a method for using the same, comprising an outer cylinder 1; The interior of the outer tube 1 is arranged to be hollow, an adjusting tube 2 is fixedly connected to the bottom of the outer tube 1, a supporting seat 3 is fixedly connected to the bottom of the adjusting tube 2, a lifting structure 4 is arranged on the top of the outer tube 1, and the lifting structures 4 are connected to each other through connecting components. The lifting structure 4 can drive the sodium-cooled fast reactor core flowmeter 5 to rise and fall vertically inside the outer tube 1, the adjusting tube 2 and the supporting seat 3 through the connecting components. An exhaust pipe 6 is connected to the top of the right side of the outer tube 1, and a pressure maintaining structure a 7 on a D-shaped tube a 26 and a pressure maintaining structure b 29 on a D-shaped tube b 27 surrounding the surface of the sodium-cooled fast reactor core flowmeter 5 are arranged inside the outer tube 1.

[0024] refer to Figure 2 The hoisting structure 4 includes a winch 8 fixedly connected to the top of the outer cylinder 1, and a steel cable 9 is wound on the surface of the winch 8. The side of the steel cable 9 away from the winch 8 extends to the inside of the outer cylinder 1 and is connected to the connecting assembly. A bearing support pressure bracket 10 is fixedly connected to the top of the outer cylinder 1. The bearing support pressure bracket 10 is arranged on the surface of the output end of the winch 8. A weighing module 11 is arranged at the bottom of the bearing support pressure bracket 10. The weighing module 11 can measure the hoisting load weight of the winch 8. The function of the weighing module 11 is a common measuring device realized by a pressure sensor. It utilizes that under the action of the measured pressure, the deformation amount of the object is in a certain proportion to the pressure amount. The principle is composed of a contact pressure sensor, a turbine flowmeter, a pressure transmitter, a discharge pressure sensor, etc. The pressure is generated by external loading, and the pressure acts on the deformed part of the sensor, and the deformed part changes. The sensor uses the physical parameters of the change to convert the pressure change, thereby generating pressure data and transmitting it to the master control system to stop rising as a protection system device.

[0025] refer to Figure 3The connecting assembly includes a connecting long tube 12 which is slidably connected to the inside of the outer tube 1, a connecting flange 14 is fixedly connected to the bottom of the connecting long tube 12, the bottom of the connecting flange 14 can be interconnected with the top of the sodium-cooled fast reactor core flowmeter 5, a counterweight chain 15 is fixedly connected to the top of the connecting long tube 12, 6 rollers are arranged on the upper end of the counterweight chain 15, so that the steel cable is always centered during operation, a movable pulley block 16 is fixedly connected to the top of the counterweight chain 15, and the top of the movable pulley block 16 is fixedly connected to the bottom of the steel cable 9.

[0026] refer to Figure 4 After the outer cylinder 1 is disassembled, the tail cylinder 31 is composed of a D-shaped cylinder b27, an adjustment cylinder 2 and a fixing seat 3. A turning shaft 30 is fixedly connected inside the D-shaped cylinder b29, and a sealing plate b28 is sleeved on the surface of the turning shaft 30. The outer surface of the sealing plate b28 can contact the inner wall of the D-shaped cylinder b27.

[0027] refer to Figure 4 A flange fixed observation window 20 is provided on the surface of the connecting long cylinder 12, and a sealing observation window 21 corresponding to the sealing pressure plate b 28 is connected to the surface of the outer cylinder 1.

[0028] refer to Figure 4 The left side of the D-shaped cylinder b 27 is threadedly connected with a pressure plate pin 22, the right end of the pressure plate pin 22 passes through the tail cylinder 31 and extends to the top of the sealing pressure plate b 30, and the surface of the D-shaped cylinder b 27 is connected to a spare inflation hole 23 located at the top of the pressure plate pin 22, and the pressure plate pin 22 locks the sealing pressure plate b 29 by a taper locking method.

[0029] refer to Figure 4 The surface of the adjustment tube 2 is connected with a plurality of sight glasses 24. The outer surface of the adjustment tube 2 is surrounded by an adjustment rod 25. The end of the adjustment rod 25 close to the adjustment tube 2 passes through the adjustment tube 2 and extends to the inside of the adjustment tube 2. The adjustment rod 25 is threadedly connected to the adjustment tube 2. The inner end of the adjustment rod 25 can contact the surface of the sodium-cooled fast reactor core flow meter 5. A searchlight is installed above the sight glass 24 to facilitate observation of the real object in the barrel. The adjustment tube 2 is made of 304 stainless steel, with a maximum outer diameter of 650mm and an inner diameter of 570mm. A hook is arranged above the sight glass 24, and a lead plate can be hung on the surface of the hook to reduce the radiation irradiation area and reduce the risk of radiation to the operator.

[0030] refer to Figure 1 , a special device for disassembling and assembling a core flow meter of a sodium-cooled fast reactor and a method for using the same.

[0031] Disassembly includes the following steps: S1: Use a sling to move the outer cylinder 1 to the top of the sodium-cooled fast reactor core flowmeter 5, and the winch 8 releases the steel cable 9, so that the steel cable 9 uses the movable pulley group 16 to carry the connecting long cylinder 12 to move downward. When the connecting long cylinder 12 moves to the top of the sodium-cooled fast reactor core flowmeter 5, the connecting long cylinder 12 is connected to the sodium-cooled fast reactor core flowmeter 5 by using the connecting flange 14. When the two are connected, start the winch 8 in the reverse direction, the winch 8 reels the steel cable 9 and uses the connecting long cylinder 12 to pull the sodium-cooled fast reactor core flowmeter 5 vertically upward, so that the sodium-cooled fast reactor core flowmeter 5 is completely moved to the inside of the outer cylinder 1 and is located on the top of the sealing pressure plate 19; S2: The sealing plate 19 is rotated with the turning shaft 18 as the axis. When the outer surface of the sealing plate 19 contacts the inner wall of the outer tube 1 and the outer tube 1 is divided and sealed, gas is injected into the inner part of the outer tube 1 through the inflation valve 17 to maintain a certain gas pressure inside the outer tube 1; S3: Rotate the sealing pressure plate b 28 with the turning shaft 30 as the axis to ensure sealing with the inner wall of the tail cylinder 31, remove the flange screws connecting the D-shaped cylinder a 26 and the D-shaped cylinder b 27, and use a crane to move the outer cylinder 1 to the maintenance area.

[0032] The installation consists of the following steps: S1: The outer cylinder 1 of the repaired sodium-cooled fast reactor core flowmeter 5 is lifted to the top of the tail cylinder 31 by a crane and slowly lowered so that the flanges connecting the D-shaped cylinder a 26 and the D-shaped cylinder b 27 are in contact, and then the flanges are tightened with screws.

[0033] S2: Open the sealing plate a 19 and the sealing plate b28 respectively, rotating them around the turning axis 18 and the turning axis 30, and make sure that the two plates are fully opened. Use the winch 8 to slowly lower the sodium-cooled fast reactor core flowmeter 5. When the sodium-cooled fast reactor core flowmeter 5 is stuck, the weight value of the weighing module 11 decreases, and the system stops. Observe the offset through the sight glass 24 on the surface of the adjusting tube 2 and use the adjusting rod 25 on the surface of the adjusting tube 2 to squeeze the sodium-cooled fast reactor core flowmeter 5 for displacement. After adjusting the center, continue to lower it until it is in place. S3: Loosen the connection between the adjustment tube 2 and the support seat 3, continue to lower the steel cable 9 to the set length, and then slowly lift the device so that the user can remove the connecting bolts between the connecting long tube 12 and the sodium-cooled fast reactor core flowmeter 5. When the connecting long tube 12 and the sodium-cooled fast reactor core flowmeter 5 are disconnected, the connecting long tube 12 is recovered into the outer tube 1, thereby completing the disassembly and assembly of the sodium-cooled fast reactor core flowmeter 5.

[0034] Working principle and use process of the present invention: First, ensure that the device is in a safe state, especially when sodium coolant is involved, strict safety operating procedures must be followed, check whether the lifting structure 4, connecting components, pressure-maintaining structure 7 and pressure-maintaining structure 29 are intact, confirm that they are all in an operable state, close the inflation valve 17 in the pressure-maintaining structure 7, and release the D-shaped cylinder a through the spare inflation hole 23 or other safe discharge methods 26 to ensure that there will be no pressure shock to the flowmeter and operators during the disassembly process. First, the outer cylinder 1 is hoisted to the top of the sodium-cooled fast reactor core flowmeter 5 by the external hoisting equipment, and the winch 8 is started to slowly release the steel cable 9 to drive the movable pulley block 16 and the counterweight chain 15 to move downward. When the bottom of the connecting long cylinder 12 contacts the top of the sodium-cooled fast reactor core flowmeter 5, the two are connected by connecting bolts. When the two are connected, the outer cylinder 1 is released to descend so that the outer cylinder 1 contacts the ground. During the descent of the outer cylinder 1, the winch 8 reels the connecting long cylinder 12 with the steel cable 9 to keep the steel cable 9 in a tensioned state. When the continuously descending outer cylinder 1 is sleeved on the top of the sodium-cooled fast reactor core flowmeter 5, the sodium-cooled fast reactor core flowmeter 5 is connected to the outer cylinder 1 and the guidance is completed. At the same time, the external hoist The equipment can lift the outer cylinder 1, so that the outer cylinder 1 carries the sodium-cooled fast reactor core flowmeter 5 to rise. When the sodium-cooled fast reactor core flowmeter 5 is completely off the ground, the internal winch 8 uses the steel cable 9 to reel the connecting long cylinder 12, so that the connecting long cylinder 12 carries the sodium-cooled fast reactor core flowmeter 5 and passes through the two D-shaped cylinders 26 in sequence and moves to the inside of the outer cylinder 1. During the lifting process, the operator can observe the situation in the adjustment cylinder 2 through the sight glass 24 to ensure that the sodium-cooled fast reactor core flowmeter 5 is unobstructed during the lifting process, and properly adjust the adjustment rod 25 to prevent the sodium-cooled fast reactor core flowmeter 5 from colliding with the inner wall of the adjustment cylinder 2 or the adjustment rod 25. When the sodium-cooled fast reactor core flowmeter 5 moves to the top of the D-shaped cylinder 26, the sealing pressure plate 19 is controlled to swing by the flip shaft 18. When the outer surface of the sealing pressure plate 19 is in contact with the D-shaped cylinder a When the inner walls of the upper D-shaped cylinder a 26 are in close contact and the D-shaped cylinder a 26 is completely sealed, gas is injected into the interior of the upper D-shaped cylinder a 26 through the inflation valve 17 to maintain a certain air pressure inside the upper D-shaped cylinder a 26. When the internal air pressure of the D-shaped cylinder a 26 is consistent with the external environmental air pressure, the two D-shaped cylinders a 26 are separated and the outer cylinder 1 and the top D-shaped cylinder a 26 are carried by external lifting equipment to the maintenance area for maintenance operations.

[0035] In summary: the special device for disassembling and assembling the sodium-cooled fast reactor core flowmeter and the use method thereof, which hoists and loads and unloads the sodium-cooled fast reactor core flowmeter 5 by hoisting, can greatly improve the loading and unloading safety of the sodium-cooled fast reactor core flowmeter 5, make the installation of the sodium-cooled fast reactor core flowmeter 5 more flexible, and can be adjusted according to the actual situation on site, reducing the difficulty and cost of installation.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor, comprising an outer cylinder (1); Features: The interior of the outer cylinder (1) is arranged to be hollow. The bottom of the outer cylinder (1) is fixedly connected to an adjusting cylinder (2). The bottom of the adjusting cylinder (2) is fixedly connected to a supporting seat (3). The top of the outer cylinder (1) is arranged to have a hanging structure (4). The interior of the outer cylinder (1) is arranged to have a hanging structure (4) for connecting and lifting a sodium-cooled fast reactor core flowmeter (5). The sodium-cooled fast reactor core flowmeter (5) can be connected to the hanging structure (4) through a connecting assembly. The hanging structure (4) can drive the sodium-cooled fast reactor core flowmeter (5) to vertically lift and lower inside the outer cylinder (1), the adjusting cylinder (2) and the supporting seat (3) through the connecting assembly. The top of the right side of the outer cylinder (1) is connected to an exhaust pipe (6). The interior of the outer cylinder (1) is arranged to have a pressure-maintaining structure (7) surrounding a D-shaped cylinder a (26) on the surface of the sodium-cooled fast reactor core flowmeter (5) and a pressure-maintaining mechanism (29) on a D-shaped cylinder b (27).

2. The special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor according to claim 1, characterized in that: The hoisting structure (4) comprises a winch (8) fixedly connected to the top of the outer cylinder (1), a steel cable (9) being wound around the surface of the winch (8), the steel cable (9) extending from a side of the winch (8) to the inside of the outer cylinder (1) and being interconnected with a connecting assembly, a bearing support pressure bracket (10) being fixedly connected to the top of the outer cylinder (1), the bearing support pressure bracket (10) being sleeved on the surface of the output end of the winch (8), a weighing module (11) being arranged at the bottom of the bearing support pressure bracket (10), and the weighing module (11) being capable of measuring the hoisting load-bearing weight of the winch (8).

3. A special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor according to claim 2, characterized in that: The connection assembly comprises a connection long tube (12) slidably connected to the inside of an outer tube (1); a connection flange (14) is fixedly connected to the bottom of the connection long tube (12); the bottom of the connection flange (14) is mutually connected to the top of a sodium-cooled fast reactor core flowmeter (5); a counterweight chain (15) is fixedly connected to the top of the connection long tube (12); a movable pulley block (16) is fixedly connected to the top of the counterweight chain (15); and the top of the movable pulley block (16) is fixedly connected to the bottom of a steel cable (9).

4. The special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor according to claim 3, characterized in that: The pressure-maintaining structure (7) comprises a D-shaped cylinder a (26) and a D-shaped cylinder b (27) connected to the surface of the outer cylinder (1). The number of the D-shaped cylinders is two and they are stacked and arranged. The right sides of the two D-shaped cylinders a (26) are both connected to an inflation valve (17). The interior of the D-shaped cylinder a (26) is fixedly connected to a flip shaft (18). The surface of the flip shaft (18) is sleeved with a sealing pressure plate (19). The outer surface of the sealing pressure plate (19) can contact the inner wall of the D-shaped cylinder (26).

5. The special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor according to claim 4, characterized in that: A flange-fixed observation window (20) is provided on the surface of the connecting long tube (12), and a sealing observation window (21) corresponding to the sealing pressure plate (19) is provided on the surface of the outer tube (1).

6. The special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor according to claim 4, characterized in that: The left side of the D-shaped cylinder (26) is threadedly connected to a pressure plate pin (22); the right end of the pressure plate pin (22) passes through the outer cylinder (1) and extends to the top of the sealing pressure plate (19); and the surface of the D-shaped cylinder (26) is connected to a spare inflation hole (23) located at the top of the pressure plate pin (22).

7. The special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor according to claim 1, characterized in that: The surface of the adjusting cylinder (2) is connected to a plurality of sight glasses (24); an adjusting rod (25) is arranged around the outer surface of the adjusting cylinder (2); an end of the adjusting rod (25) close to the adjusting cylinder (2) passes through the adjusting cylinder (2) and extends into the interior of the adjusting cylinder (2); the adjusting rod (25) is threadedly connected to the adjusting cylinder (2); and the inner end of the adjusting rod (25) can contact the surface of a sodium-cooled fast reactor core flowmeter (5).

8. A method for using a special device for disassembling and assembling a core flowmeter of a sodium-cooled fast reactor according to any one of claims, characterized in that it comprises the following steps: S1: Use a crane to move the outer cylinder (1) to the top of the sodium-cooled fast reactor core flow meter (5) that has not been disassembled, and reserve a 500mm installation space between the lower flange of the support seat (3) and the mounting flange of the sodium-cooled fast reactor core flow meter (5). Use the winch (8) to release the connecting long cylinder (12), so that the steel cable (9) uses the movable pulley group (16) to carry the connecting long cylinder (12) downward. When the connecting long cylinder (12) moves to the top of the sodium-cooled fast reactor core flow meter (5), use the connecting screws to connect the lower flange of the connecting long cylinder (12) and the mounting flange of the sodium-cooled fast reactor core flow meter (5). When the two are connected, the sodium-cooled fast reactor core flow meter is disassembled at the same time. (5), reversely start the winch (8), the winch (8) reels the steel cable (9) and keeps it slightly taut, and reads the value of the weighing module (11). Use a crane to move the outer cylinder (1) below the connection support seat (3) to the flange of the outer fixed seat of the sodium-cooled fast reactor core flowmeter (5) that has not been disassembled, and observe the value of the weighing module at the same time. If it is found to be reduced, the winch (8) can slowly pull up the sodium-cooled fast reactor core flowmeter (5) connected to the connecting long tube (12), wait until the connecting support seat (3) is lowered to the bottom, stop the winch (8) from pulling up the connecting long tube (12), and at this time, use screws to connect the flange of the support seat (3) and the docking flange. The sodium-cooled fast reactor core flowmeter (5) can be pulled vertically by the connecting long tube (12) so that the sodium-cooled fast reactor core flowmeter (5) is completely moved to the inside of the outer cylinder (1) and located on the top of the sealing pressure plate (19); S2: rotating the sealing pressure plate (19) with the turning shaft (18) as the axis, and when the outer surface of the sealing pressure plate (19) contacts the inner wall of the outer cylinder (1) and the outer cylinder (1) is segmented and sealed, rotating the sealing pressure plate (28) with the turning shaft (30) as the axis, and when the outer surface of the sealing pressure plate (28) contacts the inner wall of the tail cylinder (31) and the tail cylinder (31) is segmented and sealed from the outside, injecting gas into the interior of the outer cylinder (1) through the inflation valve (17), so that a certain gas pressure is maintained inside the outer cylinder (1); S3: Remove the flange screws connecting the D-shaped cylinder a 26 and the D-shaped cylinder b 27, and use a crane to move the outer cylinder 1 to the maintenance area; S4: The repaired sodium-cooled fast reactor core flow meter (5) is hoisted to the top of the tail tube 31. When the two are connected, the sealing pressure plate a (19) and the sealing pressure plate b (28) are opened, and part of the argon gas inside the outer tube (1) is replaced with the gas inside the device, so that the internal pressure of the outer tube (1) is consistent with the internal pressure of the device. When the replacement is completed, the sodium-cooled fast reactor core flow meter (5) is slowly lowered by using a winch (8). When the sodium-cooled fast reactor core flow meter (5) is stuck, the weight value of the weighing module (11) decreases, the system stops, and the offset condition is observed through the sight glass (24) on the surface of the adjustment tube (2) and the adjustment rod (25) on the surface of the adjustment tube (2) is used to squeeze the sodium-cooled fast reactor core flow meter (5) for displacement. After adjusting the center, it continues to be lowered until it is in place; S5: Loosen the connection between the adjustment tube (2) and the support seat (3), continue to lower the steel cable (9) to the set length, and then slowly lift the lifting device so that the user can remove the connecting bolts between the connecting long tube (12) and the sodium-cooled fast reactor core flow meter (5). When the connecting long tube (12) and the sodium-cooled fast reactor core flow meter (5) are disconnected, the connecting long tube (12) is recovered into the outer tube (1), thereby completing the disassembly and assembly of the sodium-cooled fast reactor core flow meter (5).

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