A remote cleaning tool for the screw holes of the instrument grid guide posts inside a reactor.

Abstract

The present application belongs to the technical field of nuclear power plant reactor maintenance operation, and particularly relates to a long-distance cleaning tool for a reactor in-core instrument rack guide column threaded hole, which comprises: a water assembling operation component and an underwater cleaning main component; the water assembling operation component is detachably connected with the underwater cleaning main component; the water assembling operation component is used for positioning the cleaning tool and remotely connecting the underwater cleaning main component; and the underwater cleaning main component is used for cleaning the in-core instrument rack guide column threaded hole. The tool can clean the dirt and foreign matters existing in the interior of the underwater in-core instrument rack guide column threaded hole and the internal threaded surface.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power plant reactor maintenance and operation technology, specifically relating to a remote cleaning tool for the screw holes of the guide columns of the instrument grid inside the reactor. Background Technology

[0002] During refueling and overhaul of a nuclear power plant unit, foreign objects or dirt may be present on the threaded surfaces of the guide post bolt holes of the in-reactor instrument grid in the upper reactor internals of the AP1000 nuclear power unit. This could prevent the guide extension posts of the in-reactor instrument grid from being screwed into the bolt holes. Since the entire in-reactor instrument grid system is located inside the upper reactor internals, approximately 8 meters underwater, and subject to high levels of radiation, personnel cannot perform close-range cleaning of the guide post bolt holes.

[0003] To address the aforementioned issues, a remote cleaning tool for the guide post bolt holes of the in-core instrument grid needs to be developed. This tool would clean the guide post bolt holes of the in-core instrument grid that contain foreign objects or dirt, thereby reducing operational risks during overhauls and saving overhaul time. Summary of the Invention

[0004] The purpose of this invention is to provide a tool for long-distance cleaning of the threaded holes of the instrument grid guide posts inside a reactor. This tool can clean dirt and foreign matter inside the threaded holes and on the surface of the internal threads of the instrument grid guide posts inside an underwater reactor from a distance above an operating platform.

[0005] Technical solution to achieve the purpose of this invention:

[0006] A remote cleaning tool for the guide post screw holes of an instrument grid inside a reactor includes: an above-water assembly and operation component and an underwater cleaning main component; the above-water assembly and operation component and the underwater cleaning main component are detachably connected; the above-water assembly and operation component is used to position the cleaning tool and remotely connect to the underwater cleaning main component; the underwater cleaning main component is used to clean the guide post screw holes of the instrument grid inside the reactor.

[0007] Furthermore, the waterborne assembly operation components include a positioning component, an extension rod assembly, a hoisting head assembly, and a universal level; the positioning component, the hoisting head assembly, and the universal level are respectively connected to the top of the extension rod assembly; the positioning component is used to position the extension rod assembly; the hoisting head assembly is used to connect to a crane to prevent the tool from falling into the equipment during operation; the universal level is used to observe whether the entire extension rod assembly is vertical.

[0008] Furthermore, the extension rod assembly includes multiple extension rod sections, each with a detachable anti-drop rod at its top, and adjacent extension rods are connected by pins and extension rod connectors.

[0009] Furthermore, the underwater cleaning main component includes: a connecting shaft, a pressure cap, a fixing ring, a shaft seal ring, a vacuum cleaner connector, a lower end cap, a brush head, a thin nut, a top fixing bolt, and a bottom fixing bolt; the fixing ring is sleeved and connected to the outside of the connecting shaft, the pressure cap is placed on top of the fixing ring, and the pressure cap is fixedly connected to the upper end of the connecting shaft by the top fixing bolt, thereby fixing and limiting the fixing ring; the vacuum cleaner connector is fixedly installed on the fixing ring, and the vacuum cleaner connector is used to connect to the underwater vacuum cleaner; the connecting shaft has an axial flow channel along the axial direction at the shaft center, and a radial flow channel in the middle. The axial flow channel and the radial flow channel are connected to form the internal flow channel of the connecting shaft; the shaft seal sealing ring is sleeved on the opening position of the radial flow channel of the connecting shaft, and the radial flow channel is connected to the internal cavity of the shaft seal sealing ring, which is connected to the vacuum cleaner connecting joint; the axial flow channel is connected to the opening at the bottom of the connecting shaft; the lower end cover is fixedly connected to the bottom end of the fixing ring by the bottom fixing bolt, and the shaft seal sealing ring is fixed and limited by the lower end cover; the brush head is installed at the lower end of the connecting shaft, and the thin nut is placed at the bottom of the brush head. The thin nut is threadedly connected to the connecting shaft, and the brush head is fixed and limited by the thin nut.

[0010] Furthermore, the connecting shaft of the underwater cleaning main component is connected to the end of the bottom extension rod of the extension rod assembly of the above-water assembly operation component, and the connection is detachable via a pin.

[0011] Furthermore, the lower end of the connecting shaft is provided with a flat key, and the inner ring of the brush head is provided with a keyway. The flat key matches the keyway, and the connecting shaft provides circumferential rotational power to the brush head through the flat key.

[0012] Furthermore, a bearing is installed between the fixing ring and the connecting shaft.

[0013] Furthermore, a gap is provided between the inner side of the shaft seal ring and the outer side of the connecting shaft.

[0014] Furthermore, a flow groove is provided on the bottom side of the connecting shaft.

[0015] Furthermore, the brush head includes a brush base and a brush, with the brush fixedly mounted on the brush base; the brush is made of silicon carbide, and the brush base is made of aluminum alloy.

[0016] The beneficial technical effects of this invention are as follows:

[0017] 1. The present invention provides a remote cleaning tool for the threaded holes of the guide posts of the instrument grid inside the reactor. It enables the cleaning of the threads of the guide posts of the instrument grid inside the underwater reactor from above the operating platform. This avoids the need for manual immersion in radioactive water to clean the threads of the guide posts under fault conditions. It also avoids the need for personnel to enter the high-dose area of ​​the refueling pool when the upper reactor components are exposed. This effectively reduces the difficulty and risk of operation. A single repair can reduce the radiation dose to personnel by 9 person-mSv.

[0018] 2. The present invention provides a tool for long-distance cleaning of the screw holes of the guide columns of the instrument grid inside the reactor. It can also avoid personnel entering the refueling pool to clean the threads of the guide column screw holes after draining and decontaminating the refueling pool. One cleaning operation can reduce the main line construction period by about 9 hours and increase the efficiency of the power plant by about 4.5 million yuan.

[0019] 3. The present invention provides a long-distance cleaning tool for the guide post screw holes of the instrument grid inside the reactor. Compared with the shortcomings of traditional underwater vacuum cleaners that can only clean loose foreign objects and dirt on the top and upper surface of the thread teeth, the present invention can more effectively remove dirt and foreign objects from the top, root, upper and lower surfaces of the thread teeth, and can remove more firmly attached dirt, resulting in better cleaning effect and higher cleaning efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a tool for long-distance cleaning of the screw holes of the instrument grid guide column inside a reactor, provided by the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of the water assembly and operation component in a cleaning tool provided by the present invention.

[0022] Figure 3 A schematic diagram of the installation of the lifting head assembly, the screw handle assembly, and the universal level in a cleaning tool provided by the present invention;

[0023] Figure 4 This is a schematic diagram of the assembly of adjacent extension rods in an extension rod assembly of a cleaning tool provided by the present invention.

[0024] Figure 5 This is a schematic diagram of the installation of the positioning component in a cleaning tool provided by the present invention;

[0025] Figure 6 This is a schematic diagram of the underwater cleaning main component structure in a cleaning tool provided by the present invention.

[0026] Figure 7 This is a cross-sectional view of the underwater cleaning main component in a cleaning tool provided by the present invention;

[0027] Figure 8 A schematic diagram of the shaft seal sealing ring structure in a cleaning tool provided by the present invention;

[0028] Figure 9 This is a schematic diagram of the brush head structure in a cleaning tool provided by the present invention;

[0029] Figure 10 This is a schematic diagram of the bottom opening of the connecting shaft in a cleaning tool provided by the present invention;

[0030] Figure 11 This is a schematic diagram of the underwater cleaning main component of a cleaning tool provided by the present invention;

[0031] Figure 12 This is a schematic diagram of the flow channel for a cleaning tool provided by the present invention, which guides foreign objects from the screw hole into the vacuum cleaner.

[0032] In the diagram: 1-Waterborne assembly and operation components; 11-Positioning assembly; 12-Extension rod assembly; 13-Anti-drop rod; 14-Tightening handle assembly; 15-Lifting head assembly; 16-Universal level; 17-Pin; 18-Extension rod connector; 111-Oval hole clamp A; 112-Oval hole clamp B; 113-Fixing bolt; 114-Guide sleeve fine-tuning bolt; 115-Guide sleeve; 116-Pressure block A; 117-Pressure block B; 118-Pressure block C; 119-Pressure block bolt;

[0033] 2-Underwater cleaning main component; 21-Connecting shaft; 22-Pressure cap; 23-Retaining ring; 24-Bearing; 25-Shaft seal ring; 26-Vacuum cleaner connector; 27-Lower end cap; 28-Brush head; 281-Brush base; 282-Brush; 29-Flat key; 210-Thin nut; 211-Top fixing bolt; 212-Bottom fixing bolt; 214-In-stack instrument grid guide post; 218-Hose; 219-Underwater vacuum cleaner; 220-Flow channel; 221-Connecting shaft bottom thread;

[0034] 5- Waist-shaped hole. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0036] like Figure 1As shown, this invention provides a remote cleaning tool for the guide post bolt holes of an instrument grid inside a reactor, comprising: a surface assembly and operation component 1 and an underwater cleaning main component 2; the surface assembly and operation component 1 and the underwater cleaning main component 2 are detachably connected; the surface assembly and operation component 1 is used to position the cleaning tool and remotely connects to the underwater cleaning main component; the underwater cleaning main component 2 is used to clean the guide post bolt holes of the instrument grid inside the reactor. The main body of the cleaning tool is made of aluminum alloy, making it lightweight and easy to operate.

[0037] like Figure 2-4 As shown, the waterborne assembly operation component 1 includes a positioning assembly 11, an extension rod assembly 12, an anti-fall rod 13, a screw handle assembly 14, a hoisting head assembly 15, and a universal level 16. The extension rod assembly 12 includes multiple extension rod sections, each with an anti-fall rod 13 detachably connected to its top. Adjacent extension rods are connected via pins 17 and extension rod connectors 18. The hoisting head assembly 15, screw handle assembly 14, universal level 16, and positioning assembly 11 are respectively connected to the top extension rod. The hoisting head assembly 15 is used to connect to a crane to prevent the tool from falling into the equipment during operation. The universal level 16 is installed below the screw handle assembly 14 to observe whether the entire extension rod assembly 12 is vertical.

[0038] like Figure 5 As shown, the positioning assembly 11 includes: a waist-shaped hole clamping plate A 111, a waist-shaped hole clamping plate B 112, a fixing bolt 113, a guide sleeve fine-tuning bolt 114, a guide sleeve 115, a pressure block A 116, a pressure block B 117, a pressure block C 118, and a pressure block bolt 119. The top extension rod of the extension rod assembly 12 passes through the through hole in the middle of the guide sleeve 115. The guide sleeve 115 is clamped by the waist-shaped hole clamp A 111 and waist-shaped hole clamp B 112, so that the guide sleeve 115 is fitted onto the extension rod assembly 12. The extension rod assembly 12 can rotate inside the guide sleeve 115. The guide sleeve 115 is initially fixed to the waist-shaped hole 5 by the waist-shaped hole clamp A 111 and waist-shaped hole clamp B 112. The waist-shaped hole clamp A 111 and waist-shaped hole clamp B 112 are connected together by the fixing bolt 113. Then, the pressure block A 116, pressure block B 117, and pressure block C 118 are fixed to the waist-shaped hole 5 again by the pressure block bolt 119. Finally, the guide sleeve fine adjustment bolt 114 is used to adjust the precise positioning of the guide sleeve 115.

[0039] like Figure 6-7 As shown, the underwater cleaning main component 2 includes: a connecting shaft 21, a pressure cap 22, a fixing ring 23, a bearing 24, a shaft seal sealing ring 25, a vacuum cleaner connecting connector 26, a lower end cap 27, a brush head 28, a flat key 29, a thin nut 210, a top fixing bolt 211, and a bottom fixing bolt 212.

[0040] The fixing ring 23 is sleeved and connected to the outside of the connecting shaft 21. The pressure cover 22 is placed on the top of the fixing ring 23. The pressure cover 22 is fixedly connected to the upper end of the connecting shaft 21 by the top fixing bolt 211. The pressure cover 22 is used to fix and limit the fixing ring 23.

[0041] The vacuum cleaner connector 26 is fixedly installed on the retaining ring 23, and the vacuum cleaner connector 26 is quickly connected to the underwater vacuum cleaner 219 through the hose 218.

[0042] A bearing 24 is installed between the retaining ring 23 and the connecting shaft 21. When the connecting shaft 21 drives the brush head 28 to rotate, the retaining ring 23 and the vacuum cleaner connector 26 are not affected by the rotation and can remain stationary, preventing the vacuum cleaner hose from getting tangled on the underwater cleaning main body.

[0043] The connecting shaft 21 has an axial flow channel at its center along the axial direction and a radial flow channel in its middle section. The axial and radial flow channels are connected, forming the internal flow channel of the connecting shaft 21. This internal flow channel serves as the channel for the underwater vacuum cleaner to draw water during thread cleaning. A shaft seal ring 25 is fitted into the opening of the radial flow channel of the connecting shaft 21. The shaft seal ring 25 is coaxially arranged with the connecting shaft 21, and has an internal chamber, such as... Figure 8 As shown. The radial flow channel communicates with the internal chamber of the shaft seal ring 25, and the internal chamber of the shaft seal ring 25 communicates with the vacuum cleaner connector 26. The axial flow channel communicates with the opening at the bottom of the connecting shaft 21.

[0044] A gap is provided between the inner side of the shaft seal ring 25 and the outer side of the connecting shaft 21. The two maintain a small gap, which allows for smooth relative rotation between them. This ensures that the fixing ring 23 and the vacuum cleaner connector 26 are not affected by the rotation when the connecting shaft 21 rotates.

[0045] The lower end cover 27 is fixedly connected to the bottom end of the fixing ring 23 by the bottom fixing bolt 212, and the lower end cover 27 is used to fix and limit the shaft seal sealing ring 25.

[0046] The brush head 28 is installed at the lower end of the connecting shaft 21. The thin nut 210 is placed at the bottom of the brush head 28. The thin nut 210 matches the thread 221 at the bottom of the connecting shaft. The thin nut 210 is threadedly connected to the connecting shaft 21. Tightening the thin nut 210 on the connecting shaft 21 presses the thin nut 210 against the bottom of the brush head 28. The thin nut 210 fixes and limits the brush head 28 and prevents the brush head 28 from falling off the connecting shaft 21.

[0047] The lower end of the connecting shaft 21 is provided with a flat key 29, and the inner ring of the brush head 28 is provided with a keyway. The flat key 29 matches the keyway, and the connecting shaft 21 provides circumferential rotational power to the brush head 28 through the flat key 29.

[0048] like Figure 9 As shown, the brush head 28 includes a brush base 281 and a brush 282, with the brush 282 fixedly mounted on the brush base 281. The brush head 28 is the main part of the tool for cleaning, and can clean the threads of the guide posts of the instrument grid within the stack. The tool is driven up and down by the connecting shaft 21 to achieve the cleaning effect. The brush 282 is a custom-made consumable made of silicon carbide; the brush base 281 is made of aluminum alloy.

[0049] The connecting shaft 21 of the underwater cleaning main component is connected to the end of the bottom extension rod of the extension rod assembly 12 of the above-water assembly operation component, and is detachably connected by a pin 17.

[0050] After the dirt on the threads of the guide column screw hole of the instrument grid in the stack is cleaned off by the brush head 28, it enters the internal flow channel of the connecting shaft 21 through the opening at the bottom of the connecting shaft 21 with the water flow, and then enters the internal chamber of the shaft seal sealing ring 25. Finally, it is sucked away by the underwater vacuum cleaner through the vacuum cleaner connection joint 26.

[0051] like Figure 10 As shown, a flow channel 220 is opened on the bottom side of the connecting shaft 21. When the brush head 28 cleans the bottom of the guide post screw hole of the instrument grid in the stack, the opening at the bottom of the connecting shaft 21 may contact the bottom surface of the guide post screw hole. At this time, dirt can enter the internal flow channel of the connecting shaft 21 through the flow channel 220 and then be sucked out by the underwater vacuum cleaner. When cleaning the screw hole, the operator connects the underwater vacuum cleaner to the vacuum cleaner connector 26 of the underwater cleaning main component on the water operating platform. Then, the underwater cleaning main component is extended downward to the top of the guide post 214 of the instrument grid in the stack that needs to be cleaned. Through the observation of the underwater camera, the brush head 28 is aligned with the guide post and placed downward. The brush head 28 slowly enters the guide post screw hole. After the brush head 28 contacts the threaded hole of the guide post of the instrument grid in the stack, the operator starts the underwater vacuum cleaner on the platform and rotates the cleaning tool connecting shaft 21 clockwise to rotate the brush head 28. Through the tool's own gravity or by applying slight downward pressure, the tool moves downward, thus moving the brush head downward to clean the threaded hole. During the thread cleaning process, dirt and foreign objects on the thread surface enter the internal flow channel of the connecting shaft 21 through the opening at the bottom of the connecting shaft 21. After passing through the chamber inside the shaft seal ring 25, they are sucked away by the underwater vacuum cleaner through the vacuum cleaner connecting joint 26. Once the brush head 28 reaches the bottom of the threaded hole, the cleaning tool connecting shaft 21 is rotated counterclockwise to rotate the brush head 28 and apply an upward lifting force to move the tool upward, thus moving the brush head 28 upward to continue cleaning the threaded hole.

[0052] like Figure 10-11As shown, the remote cleaning of the guide post screw holes of the instrument grid inside the reactor core, using a tool provided by this invention, includes the following steps:

[0053] Step 1: Take out the underwater cleaning main unit from the storage box and connect the vacuum cleaner connector 26 of the underwater cleaning main unit to the underwater vacuum cleaner 219 through the hose 218;

[0054] Step 2: Take out the water assembly operation parts from the storage tank, insert the anti-drop rod 13 into the top extension rod of the extension rod assembly 12, and then fix the underwater cleaning main body parts to the end of the bottom extension rod of the extension rod assembly 12 by means of a pin connection.

[0055] Step 3: Continue connecting the other extension rods of extension rod assembly 12 to the adjacent extension rod joints. When installing each extension rod section, insert the anti-drop rod 13 into the currently assembled extension rod to prevent the unassembled tool from falling into the instrument grid guide post 214 inside the stack.

[0056] Step 4: The lifting head assembly 15 above the top extension rod can be connected to the crane to prevent the tool from falling during operation. Then, the universal level 16 is installed below the screw handle assembly 14 to facilitate the operator to observe whether the extension rod is vertical. At the same time, the crane can provide an upward force when grinding the lower surface of the thread.

[0057] Step 5: The operator slowly lowers the extension rod on the platform. The underwater cleaning main component extends downward to the top of the in-pile instrument grid guide post 214 that needs to be cleaned. Observing through the underwater camera, the brush head 28 is aligned with the in-pile instrument grid guide post 214 and placed downward in the same way, so that the brush head 28 is inserted into the screw hole of the in-pile instrument grid guide post.

[0058] Step 6: After the brush head 28 makes contact with the threaded guide post of the instrument grid in the stack, the operator can clearly feel that the tool is lighter. The operator starts the underwater vacuum cleaner 219 on the platform.

[0059] Step 7: After the underwater vacuum cleaner 219 is started, the operator rotates the cleaning tool connecting shaft 21 clockwise, causing the brush head 28 to rotate. Through the tool's own gravity, or by applying slight downward pressure, the tool moves downwards, thus moving the brush head 28 downwards to clean the threaded surface. While cleaning the threaded surface of the threaded hole, the underwater vacuum cleaner sucks away the dirt and foreign objects cleaned from the threaded surface through the bottom opening of the connecting shaft 21 and its internal flow channel via the vacuum cleaner connecting connector 26.

[0060] Step 8: When the brush head 28 reaches the bottom of the screw hole, the operator rotates the cleaning tool connecting shaft 21 counterclockwise to rotate the brush head 28 and applies an upward lifting force to the tool so that the tool moves upward as a whole, thereby moving the brush head 28 upward to clean the thread surface again.

[0061] Step 9: After repeated cleaning, turn off the underwater vacuum cleaner and the operator lifts the main underwater cleaning unit to the top of the operating platform;

[0062] Step 10: Disconnect the connecting hose between the vacuum cleaner connector 26 of the underwater cleaning main component and the underwater vacuum cleaner;

[0063] Step 11: Clean the surface of the main body parts and remove water stains. Finally, put them into the storage box in the designated position for storage.

[0064] Step 12: Sort and process the foreign objects extracted from the underwater vacuum cleaner according to regulations.

[0065] 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. A remote cleaning tool for reactor in-core instrumentation rack guide column bolt holes, characterized by, The utility model relates to a kind of water surface assembly operation components and underwater cleaning main body components;Water surface assembly operation components (1) are detachably connected with underwater cleaning main body components (2);Water surface assembly operation components (1) are used to position cleaning tool, remotely connect underwater cleaning main body components;Underwater cleaning main body components (2) are used to clean the screw hole of in-pile instrument shelf guide column; The water surface assembly operation components (1) include positioning assembly (11), extension rod assembly (12), and positioning assembly (11) is used to position extension rod assembly (12);Positioning assembly (11) includes: waist hole clamping plate A (111), waist hole clamping plate B (112), fixed bolt (113), guide sleeve fine adjustment bolt (114), guide sleeve (115), pressing block A (116), pressing block B (117), pressing block C (118), pressing block bolt (119);The top extension rod of extension rod assembly (12) passes through the through hole in the middle of guide sleeve (115), guide sleeve (115) is clamped by waist hole clamping plate A (111) and waist hole clamping plate B (112), so that guide sleeve (115) is sleeved on extension rod assembly (12), extension rod assembly (12) can rotate in guide sleeve (115), and guide sleeve (115) is preliminarily fixed with waist hole (5) by waist hole clamping plate A (111) and waist hole clamping plate B (112), and waist hole clamping plate A (111) and waist hole clamping plate B (112) are connected together by fixed bolt (113), then pressing block A (116), pressing block B (117) and pressing block C (118) are fixed with waist hole (5) again by pressing block bolt (119), and finally the accurate positioning of guide sleeve (115) is adjusted by guide sleeve fine adjustment bolt (114). ​ The underwater cleaning main part (2) comprises a connecting shaft (21), a gland (22), a fixing ring (23), a shaft seal ring (25), a vacuum cleaner connecting joint (26), a lower end cover (27), a brush head (28), a thin nut (210), a top fixing bolt (211), and a bottom fixing bolt (212); the fixing ring (23) is sleeved on the connecting shaft (21), the gland (22) is arranged on the top of the fixing ring (23), the gland (22) is fixedly connected with the upper end of the connecting shaft (21) through the top fixing bolt (211), and the fixing ring (23) is fixed and limited by the gland (22); the vacuum cleaner connecting joint (26) is fixedly installed on the fixing ring (23), and the vacuum cleaner connecting joint (26) is used for being connected with an underwater vacuum cleaner (219); the connecting shaft (21) is provided with an axial flow channel in the axial direction at the shaft center and a radial flow channel in the radial direction at the middle part, the axial flow channel and the radial flow channel are communicated, and the internal flow channel of the connecting shaft (21) is formed; the shaft seal ring (25) is sleeved on the opening position of the radial flow channel of the connecting shaft (21), the radial flow channel is communicated with the cavity in the shaft seal ring (25), and the cavity in the shaft seal ring (25) is communicated with the vacuum cleaner connecting joint (26); the axial flow channel is communicated with the opening at the bottom of the connecting shaft (21); the lower end cover (27) is fixedly connected with the bottom end of the fixing ring (23) through the bottom fixing bolt (212), and the shaft seal ring (25) is fixed and limited by the lower end cover (27); the brush head (28) is installed at the lower end of the connecting shaft (21), the thin nut (210) is arranged at the bottom of the brush head (28), the thin nut (210) is threadedly connected with the connecting shaft (21), and the brush head (28) is fixed and limited by the thin nut (210).

2. A tool for remote cleaning of a guide column hole of a reactor in-core instrument rack according to claim 1, characterized in that, The water surface assembly operation part (1) further comprises a hoisting head assembly (15) and a universal level (16); the positioning assembly (11), the hoisting head assembly (15) and the universal level (16) are respectively connected to the top of the extension rod assembly (12); the hoisting head assembly (15) is used for being connected to a crane, so that the tool is prevented from falling into the equipment during work; the universal level (16) is used for observing whether the extension rod assembly (12) is vertical.

3. A tool for remotely cleaning a guide column hole of a reactor in-core instrument rack according to claim 2, characterized in that, The extension rod assembly (12) comprises multiple extension rods, and a drop prevention rod (13) is detachably connected to the top of each extension rod; adjacent extension rods are connected through a bolt (17) and an extension rod connecting piece (18).

4. A tool for remotely cleaning a guide column hole of a reactor in-core instrument rack according to claim 3, characterized in that, The connecting shaft (21) of the underwater cleaning main part is connected with the bottom end of the extension rod assembly (12) of the water surface assembly operation part, and is detachably connected through the bolt (17).

5. A tool for remotely cleaning a guide column hole of a reactor in-core instrument rack according to claim 1, characterized in that, The lower end of the connecting shaft (21) is provided with a flat key (29), the inner ring of the brush head (28) is provided with a key groove, the flat key (29) is matched with the key groove, and the connecting shaft (21) provides circumferential rotation power to the brush head (28) through the flat key (29).

6. A tool for remotely cleaning a guide column hole of a reactor in-core instrument rack according to claim 1, wherein, The bearing (24) is installed between the fixing ring (23) and the connecting shaft (21).

7. A tool for remotely cleaning a guide column hole of a reactor in-core instrument rack according to claim 1, wherein, The inner side of the shaft seal ring (25) and the outer side of the connecting shaft (21) are provided with a gap.

8. A tool for remotely cleaning a guide column hole of a reactor in-core instrument rack according to claim 1, characterized in that, The connecting shaft (21) is provided with a through-flow groove (220) on the bottom side.

9. A tool for remotely cleaning a guide column hole of a reactor in-core instrument rack according to claim 1, wherein, The brush head (28) comprises a brush base body (281) and a brush (282), the brush (282) is fixedly installed on the brush base body (281); the brush (282) is made of silicon carbide, and the brush base body (281) is made of aluminum alloy.

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