Method for removing waste graphite blocks used in graphite reactor decommissioning

Abstract

The present invention relates to the technical field of nuclear facility decommissioning and dismantling, and in particular to a novel waste graphite block removal device for decommissioning a graphite reactor. The device comprises a device main body, a drive assembly, a demolition knife group and a hoisting assembly. The drive assembly is arranged at the top of the device main body, the demolition knife group is arranged at the bottom of the device main body, the demolition knife group is transmission-connected to the drive assembly, and the demolition knife group can split the stacked graphite blocks one by one under the drive of the drive assembly. The hoisting assembly is arranged at the bottom of the device main body, the hoisting assembly is transmission-connected to the drive assembly, and the hoisting assembly can take out the split graphite blocks under the drive of the drive assembly. By arranging the demolition knife group, the present invention can quickly and flexibly split the stacked graphite blocks one by one, and the various cutters cooperate with each other to complete the process of splitting the graphite blocks, and sparks are not easily generated, which can effectively prevent the phenomenon of sparks generated by drilling by the drill bit and igniting potential graphite blocks.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear facility decommissioning and dismantling, in particular to a method for dismantling waste graphite blocks used in the decommissioning of a graphite reactor. Background Art

[0002] Graphite has excellent neutron moderation properties and good thermal shock resistance. Therefore, in the nuclear industry, graphite is often used as a moderator and reflector material in nuclear reactors. A graphite reactor is a type of nuclear reactor that uses graphite as a neutron moderator. Its core is composed of large cubes of graphite stacked together, into which nuclear fuel rods are inserted. When the reactor is started, the fast neutrons released by the fission of uranium-235 are slowed by the graphite and then collide with new uranium-235 nuclei, triggering a chain reaction. Exposure to fast neutrons can cause nuclear graphite to swell, deform, bend, or mechanically fracture. After a nuclear facility is decommissioned, this discarded nuclear graphite needs to be removed.

[0003] However, the removal of waste graphite faces many problems: 1. The reserves of waste graphite are large, and there are currently few professional graphite removal equipment, making manual removal inefficient; 2. Graphite is directly irradiated in the core, has high activity, and has great potential. If it is removed manually, it will greatly affect the health of the workers; 3. There are many long-lived radioactive nuclides in waste graphite. If sparks or open flames are encountered during handling, the graphite may be burned, expanding the scope of environmental pollution; 4. Waste graphite is usually irregular in shape and has low strength, making it difficult to completely remove and prepare and package the entire thing.

[0004] Prior art CN115376714A discloses a dismantling device and dismantling equipment, which includes a main body, a driving member, a first drill bit, an alignment member and a second drill bit. The driving member is fixed to the main body, and the first drill bit is connected to the driving member. The driving member is configured to drive the first drill bit to move relative to the main body along a first direction. The alignment member is used to align the first drill bit with the fixed structure on the graphite block. The second drill bit is connected to the main body. When the dismantling device is in a demolition mode, the first drill bit is aligned with the fixed structure on the graphite block, and the driving member drives the first drill bit to feed along the first direction so that the first drill bit can destroy the fixed structure. When the dismantling device is in a tensioning mode, the main body drives the first drill bit and the second drill bit to feed along the first direction so that the first drill bit and the second drill bit can drill into the graphite block and be tightened and fixed to the graphite block. The above-mentioned dismantling device can achieve stable grasping of graphite blocks with high density and large weight, solving the problem of difficult nuclear graphite dismantling.

[0005] The above device still has certain defects when in use. When in the demolition mode, the first drill bit is used directly to destroy the fixed structure. Sparks may be generated when the drill bit drills, causing potential waste graphite blocks to be ignited and causing environmental pollution; when in the tensioning mode, the waste graphite blocks are removed in a tensioning manner, which easily causes the waste graphite blocks to break, and cannot well ensure the integrity of the waste graphite blocks when they are removed, affecting further demolition work. Summary of the Invention

[0006] In order to overcome the above-mentioned shortcomings, the present invention aims to provide a technical solution that can solve the above-mentioned problems.

[0007] A method for removing waste graphite blocks used in decommissioning a graphite reactor is used to remove nuclear graphite in a reactor pit. The nuclear graphite is composed of a plurality of stacked graphite blocks. The method comprises a device body, a drive assembly, a demolition knife group, and a hoisting assembly. The drive assembly is arranged at the top of the device body, the demolition knife group is arranged at the bottom of the device body, and the demolition knife group is connected to the drive assembly in a transmission manner. The demolition knife group can separate the stacked graphite blocks one by one under the drive of the drive assembly. The hoisting assembly is arranged at the bottom of the device body and is connected to the drive assembly in a transmission manner. The hoisting assembly can remove the separated graphite blocks under the drive of the drive assembly.

[0008] As a further solution of the present invention: the demolition tool group includes a milling cutter drive rod cabin, which is arranged at the bottom of the device body and is transmission-connected to the drive assembly. A milling cutter drive rod is provided in the milling cutter drive rod cabin, and a milling cutter head is provided at the lower end of the milling cutter drive rod.

[0009] As a further solution of the present invention: the demolition tool set includes a drill drive rod cabin, which is arranged at the bottom of the device body and is transmission-connected to the drive assembly. A drill drive rod is provided in the drill drive cabin, and a drill bit is provided at the lower end of the drill drive rod.

[0010] As a further solution of the present invention: the demolition tool set includes a cutter head drive rod cabin, which is arranged at the bottom of the device body and is transmission-connected to the drive assembly. A cutter head drive rod is provided in the cutter head drive cabin, and a cutting head is provided at the lower end of the cutter head drive rod.

[0011] As a further solution of the present invention: the lifting assembly includes a lifting drive rod cabin, the lifting drive rod cabin is arranged at the bottom of the device body and is transmission-connected to the drive assembly, a lifting drive rod is provided in the lifting drive rod cabin, and four multi-joint lifting arms are provided at the lower end of the lifting drive rod. The four multi-joint lifting arms are distributed in a circular array with the axis of the lifting drive rod as the center, and a steel wire rope is provided in the multi-joint lifting arm.

[0012] As a further solution of the present invention: an elastic support arm is provided at the bottom of the device body, a support plate is provided at the lower end of the elastic support arm, and a through hole is opened on the support plate for the demolition knife group and the lifting assembly to pass through.

[0013] As a further solution of the present invention: a limit frame is provided on the top of the device body, the limit frame includes a limit top plate, and limit side plates are provided around the limit top plate. The limit top plate and the limit side plates cooperate to form a limit cavity, and the drive component is arranged in the limit cavity.

[0014] As a further solution of the present invention: the milling cutter head is cylindrical.

[0015] As a further solution of the present invention: the cutting head is wedge-shaped.

[0016] As a further solution of the present invention: a replacement joint is provided at the top of the limiting top plate.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention has a compact and reasonable structure, is easy to operate, has a low production cost, and has a high market promotion value.

[0019] 2. The present invention can quickly and flexibly split the stacked graphite blocks one by one by providing a demolition tool group. Moreover, the tools cooperate with each other to complete the process of splitting the graphite blocks, and it is not easy to generate sparks, which can effectively avoid the phenomenon of sparks generated by drilling by the drill bit and igniting the potential graphite blocks.

[0020] 3. The present invention provides a lifting assembly, which can well wrap the graphite block during the process of removing the graphite block. Compared with the existing technology that adopts suction, pulling or dragging, it more effectively ensures the integrity of the waste graphite block during removal and improves work efficiency.

[0021] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] Figure 2 It is a schematic diagram of the structure of a single graphite block.

[0025] Figure 3 It is a schematic structural diagram of the milling cutter head of the present invention.

[0026] Figure 4 It is a schematic diagram of the drill bit structure of the present invention.

[0027] Figure 5 It is a structural schematic diagram of the multi-joint lifting arm of the present invention.

[0028] In the figure: 100, device body, 200, drive assembly, 300, demolition tool group, 400, lifting assembly, 500, elastic support arm, 600, support plate, 700, limit frame, 800, replacement joint, 900, graphite block, 310, milling cutter drive rod cabin, 320, milling cutter drive rod, 330, milling cutter head, 340, drill bit drive rod cabin, 350, drill bit drive rod, 360, drill bit, 370, cutter head drive rod cabin, 380, cutter head drive rod, 390, cutting cutter head, 410, lifting drive rod cabin, 420, lifting drive rod, 430, multi-joint lifting arm, 440, wire rope, 610, through hole, 710, limit top plate, 720, limit side plate, 910, steel plate, 920, steel pipe hole, 930, pin hole. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] See also Figures 1 to 5 In an embodiment of the present invention, a method for removing waste graphite blocks used for decommissioning a graphite reactor is provided, which is used to remove nuclear graphite in a reactor pit. The nuclear graphite is composed of a plurality of stacked graphite blocks 900. The surface of a single graphite block 900 is wrapped with a steel plate 910. The surface of the steel plate 910 is provided with steel pipe holes 920 and pin holes 930. The stacked graphite blocks 900 are connected by inserting pins between the pin holes 930. The steel pipes are inserted into the graphite blocks 900 through the steel pipe holes 920 on the steel plate 910.

[0031] A method for removing waste graphite blocks used in the decommissioning of a graphite reactor includes a device body 100, a drive assembly 200, a demolition knife group 300 and a hoisting assembly 400. The drive assembly 200 is arranged at the top of the device body 100, the demolition knife group 300 is arranged at the bottom of the device body 100, and the demolition knife group 300 is transmission-connected to the drive assembly 200. The demolition knife group 300 can dismantle the stacked graphite blocks 900 one by one under the drive of the drive assembly 200. The hoisting assembly 400 is arranged at the bottom of the device body 100, and the hoisting assembly 400 is transmission-connected to the drive assembly 200. The hoisting assembly 400 can remove the disassembled graphite blocks 900 under the drive of the drive assembly 200.

[0032] During the removal process of the graphite block 900, the driving component 200 first drives the demolition knife group 300 to operate, destroying the steel plate 910, steel pipe and pins, separating the adjacent graphite blocks 900, and exposing the graphite blocks 900. Then the driving component 200 drives the lifting component 400 to operate to remove the exposed graphite block 900, and the removal of the graphite block 900 is completed.

[0033] The demolition tool assembly 300 includes a milling cutter drive rod compartment 310, which is arranged at the bottom of the device body 100 and is in transmission connection with the drive assembly 200. A milling cutter drive rod 320 is arranged in the milling cutter drive rod compartment 310, and a milling cutter head 330 is arranged at the lower end of the milling cutter drive rod 320. When performing milling work, its working state is as follows: Figure 3 As shown, the drive assembly 200 transmits power to the milling cutter drive rod compartment 310, driving the milling cutter drive rod 320 to move downward, thereby driving the milling head 330 to move downward, milling the steel plate 910 above the graphite block 900, and milling it to a thickness of 1 mm, and then driving the milling cutter drive rod 320 to rise and reset for subsequent dismantling work.

[0034] The demolition tool set 300 includes a drill drive rod compartment 340, which is arranged at the bottom of the device body 100 and is in transmission connection with the drive assembly 200. A drill drive rod 350 is arranged in the drill drive compartment, and a drill bit 360 is arranged at the lower end of the drill drive rod 350. When drilling, the working state is as follows: Figure 4 As shown, the drive assembly 200 provides power to the drill drive rod compartment 340, driving the drill drive rod 350 to move downward, thereby driving the drill bit 360 to move downward and drill into the steel pipe, so that the wall thickness of the steel pipe is only 1 mm, and then driving the drill drive rod 350 to rise and reset for subsequent demolition work.

[0035] The demolition tool group 300 includes a cutter head drive rod cabin 370, which is arranged at the bottom of the device body 100 and is connected to the drive assembly 200. A cutter head drive rod 380 is provided in the cutter head drive cabin, and a cutting head 390 is provided at the lower end of the cutter head drive rod 380. When the milling and drilling work is completed, the drive assembly 200 transmits power to the cutter head drive rod cabin 370, driving the cutter head drive rod 380 to move downward, thereby driving the cutting head 390 to move downward to push open the milled steel plate 910 and cut off the drilled steel pipe, exposing the graphite block 900, and then driving the cutter head drive rod 380 to rise and reset for subsequent lifting work.

[0036] The hoisting assembly 400 includes a hoisting drive rod cabin 410, which is arranged at the bottom of the device body 100 and is in transmission connection with the drive assembly 200. A hoisting drive rod 420 is arranged in the hoisting drive rod cabin 410, and four multi-joint hoisting arms 430 are arranged at the lower end of the hoisting drive rod 420. The four multi-joint hoisting arms 430 are distributed in a circular array with the axis of the hoisting drive rod 420 as the center. A steel wire rope 440 is arranged in the multi-joint hoisting arm 430. When performing hoisting work, its working state is as follows: Figure 5 As shown, when the graphite block 900 is exposed, the drive assembly 200 transmits power to the lifting drive rod cabin 410, driving the lifting drive rod 420 to move downward along the steel pipe hole 920 after the steel pipe is cut to the bottom of the graphite block 900, and the wire rope 440 is deformed, causing the multi-joint lifting arm 430 to extend to the surrounding areas along the gap between the graphite block 900 and the bottom steel plate 910. When it extends to touch the side steel plate 910, the head of the multi-joint lifting arm 430 collides with it and reflects to change the direction of movement, causing it to move upward to wrap the graphite block 900, and then drive the lifting drive rod 420 to rise, move the graphite block 900 out, and complete the removal of the single graphite block 900.

[0037] It should be noted that for the steel plate 910 and the steel pipe, the milling head 330 first mills the steel plate 910 to a thickness of 1 mm, and then the drill bit 360 drills the steel pipe to a thickness of 1 mm, and then the cutting head 390 destroys the steel plate 910 and the steel pipe, which can effectively avoid the generation of sparks and ignition of the potential graphite block 900. The drive component 200 can adopt a hydraulic cylinder, an air cylinder, a worm gear, a gear rack and other structures, which can break the tool group 300 and the lifting component 400 to complete the dismantling work, avoid the use of any motors and electronic components, and prevent the occurrence of device failure due to excessive radiation dosage in the graphite reactor.

[0038] An elastic support arm 500 is provided at the bottom of the device body 100, and a support plate 600 is provided at the lower end of the elastic support arm 500. A through hole 610 is provided on the support plate 600 for the demolition knife group 300 and the lifting assembly 400 to pass through. In this way, during the demolition work, the support plate 600 maintains contact with the graphite block 900 under the action of the elastic support arm 500, which can ensure the stable progress of the demolition work.

[0039] A limiting frame 700 is provided on the top of the device body 100, and the limiting frame 700 includes a limiting top plate 710. Limiting side plates 720 are provided around the limiting top plate 710. The limiting top plate 710 and the limiting side plates 720 cooperate to form a limiting cavity. The driving component 200 is arranged in the limiting cavity. During the operation of the device, the displacement of the driving component 200 can be limited to prevent its excessive displacement from causing device failure.

[0040] In order to ensure the milling effect, the milling cutter head 330 is cylindrical.

[0041] The cutting blade 390 is wedge-shaped, which makes the cutting blade 390 sharper and further improves the demolition efficiency.

[0042] A replacement joint 800 is provided at the top of the limiting top plate 710, and the device body 100 can be detachably installed on the control device with the help of the replacement joint 800. During the dismantling process, the device body 100 is driven to move by the control device to carry out the dismantling work. The control device can adopt a multi-axis robotic arm, a multi-head gantry bracket, a crane, etc.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for removing waste graphite blocks used in decommissioning a graphite reactor, which is used to remove nuclear graphite in a reactor pit. The nuclear graphite is composed of a plurality of graphite blocks stacked together, and is characterized in that: include: Device body; A drive assembly is arranged on the top of the device body; The demolition knife group is arranged at the bottom of the device body and is connected to the driving assembly. The demolition knife group can separate the stacked graphite blocks one by one under the drive of the driving assembly. The hoisting assembly is arranged at the bottom of the device body and is connected to the driving assembly in a transmission manner. The hoisting assembly can take out the split graphite blocks under the drive of the driving assembly; The demolition tool set includes a milling cutter drive rod cabin, a drill bit drive rod cabin and a cutter head drive rod cabin, wherein the milling cutter drive rod cabin is arranged at the bottom of the device body and is transmission-connected to the drive assembly, a milling cutter drive rod is arranged in the milling cutter drive rod cabin, and a milling cutter head is arranged at the lower end of the milling cutter drive rod; the drill bit drive rod cabin is arranged at the bottom of the device body and is transmission-connected to the drive assembly, a drill bit drive rod is arranged in the drill bit drive cabin, and a drill bit is arranged at the lower end of the drill bit drive rod; the cutter head drive rod cabin is arranged at the bottom of the device body and is transmission-connected to the drive assembly, a cutter head drive rod is arranged in the cutter head drive cabin, and a cutting cutter head is arranged at the lower end of the cutter head drive rod; When the demolition cutter group performs milling work, the drive assembly transmits power to the milling cutter drive rod compartment, drives the milling cutter drive rod to move downward, thereby driving the milling cutter head to move downward, milling the steel plate above the graphite block, and milling to a thickness of 1mm, and then drives the milling cutter drive rod to rise and reset to perform subsequent demolition work; When the demolition tool group is drilling, the drive assembly provides power to the drill drive rod compartment, driving the drill drive rod to move downward, thereby driving the drill to move downward and drill into the steel pipe, so that the wall thickness of the steel pipe is only 1mm, and then the drill drive rod is driven to rise and reset to perform subsequent demolition work; When the milling and drilling work is completed, the drive assembly transmits power to the cutter head drive rod cabin, driving the cutter head drive rod to move downward, thereby driving the cutting head to move downward to push open the milled steel plate and cut off the drilled steel pipe, exposing the graphite block, and then driving the cutter head drive rod to rise and reset for subsequent lifting work.

2. The method for removing waste graphite blocks for decommissioning a graphite reactor according to claim 1, wherein: The lifting assembly includes a lifting drive rod cabin, which is arranged at the bottom of the device body and is transmission-connected to the drive assembly. A lifting drive rod is provided in the lifting drive rod cabin, and four multi-joint lifting arms are provided at the lower end of the lifting drive rod. The four multi-joint lifting arms are distributed in a circular array with the axis of the lifting drive rod as the center, and a steel wire rope is provided in the multi-joint lifting arm.

3. The method for removing waste graphite blocks for decommissioning a graphite reactor according to claim 1, wherein: An elastic support arm is provided at the bottom of the device body, and a support plate is provided at the lower end of the elastic support arm. A through hole is opened on the support plate for the demolition knife group and the lifting component to pass through.

4. The method for removing waste graphite blocks for decommissioning a graphite reactor according to claim 1, wherein: A limit frame is provided on the top of the device body, which includes a limit top plate. Limit side plates are provided around the limit top plate. The limit top plate and the limit side plates cooperate to form a limit cavity, and the drive component is arranged in the limit cavity.

5. The method for removing waste graphite blocks for decommissioning a graphite reactor according to claim 1, characterized in that: The milling head is cylindrical.

6. The method for removing waste graphite blocks for decommissioning a graphite reactor according to claim 1, characterized in that: The cutting head is wedge-shaped.

7. The method for removing waste graphite blocks for decommissioning a graphite reactor according to claim 4, characterized in that: The top of the limiting top plate is provided with a replacement joint.

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