Device and method for automatically removing radioactive contaminants from valve chamber

Abstract

The present invention belongs to the technical field of internal contamination of valve chambers, and specifically relates to an automatic device and method for removing radioactive contamination from valve chambers, including a movable trolley, a filter, a fluid transmission pump, a mechanical arm, and a connecting pipe. The device and method can replace manual work to automatically remove radioactive substances deposited inside the valve chamber, residual radioactive liquid, and metal particles generated by grinding, thereby reducing the risk of radiation exposure and contamination of personnel, improving the decontamination effect, reducing the radiation source items of the unit, reducing the amount of radioactive waste generated, and improving on-site work efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of internal dirt in a valve chamber, and in particular relates to a device and method for automatically removing radioactive dirt from a valve chamber. Background Art

[0002] At present, in the radioactive environment inside nuclear power plants, the removal of radioactive contaminants (solids and liquids) inside valve chambers is generally done manually. Radioactive substances deposited in the valve chamber and metal particles produced by grinding the valve seat sealing surface are removed by manual wiping, and radioactive liquids remaining in the valve chamber are cleaned by manual wiping or using simple suction tools.

[0003] The existing decontamination methods have the following problems: (1) The dose rate inside the valve cavity can reach tens to hundreds of mSv / h, and the decontamination personnel will be exposed to high radiation exposure and the risk of contamination; (2) In a high-radiation environment, the operation time must be strictly controlled, and the decontamination personnel can only do a simple wipe, resulting in poor decontamination effect; (3) The rags and tools used in the decontamination process become high-dose rate waste after being contaminated, increasing the amount of radioactive waste. Waste collection and transportation work will further increase the radiation dose of personnel; (4) Manual decontamination is difficult to remove stubborn dirt and metal particles, and the decontamination effect is poor.

[0004] During the overhaul of a nuclear power plant, a large amount of valve dismantling and maintenance work needs to be carried out, and the internal sealing surface of the valve cavity or parts replacement work needs to be carried out on some valves. Due to the structural characteristics of the valve cavity and the arrangement of the pipeline, radioactive materials and residual radioactive liquids with high dose rates (tens to hundreds of mSv / h) are easily deposited in the valve cavity, causing high dose exposure to maintenance personnel and affecting the maintenance work. On the other hand, the wear-resistant cladding layer of the valve sealing surface is mainly made of cobalt-containing alloy materials, such as Stellite6 alloy (Co-59 element accounts for 53.9%). EPRI (Electric Power Research Institute) research shows that grinding the valve sealing surface will produce cobalt-containing metal particles with a size of 4 to 40μm. Due to the movement of water molecules, such particles can remain suspended and can circulate in the primary circuit of the nuclear power unit for a long time. After entering the core, the cobalt (Co-59) metal particles will be activated by neutrons to generate Co-60. Taking 40g of cobalt entering the primary circuit system each year as an example, after two cycles, about 3200Ci of Co-60 will be generated, which will continuously increase the radiation source level of the nuclear power unit. Therefore, it is necessary to carry out decontamination work inside the valve cavity to remove the radioactive residues deposited inside the valve cavity, residual radioactive liquid, and cobalt (Co-59) metal particles produced by grinding.

[0005] Manual decontamination work inside the valve cavity leads to high risks of radiation exposure and contamination to personnel, poor decontamination results, increased radioactive waste, and low work efficiency. Summary of the invention

[0006] In view of the above shortcomings, the purpose of the present invention is to provide a device and method for automatically removing radioactive contaminants from a valve chamber, which can replace manual work to automatically remove radioactive substances deposited inside the valve chamber, residual radioactive liquids and metal particles produced by grinding, thereby reducing the risk of radiation exposure and contamination of personnel, improving the decontamination effect, reducing the radiation source items of the unit, reducing the amount of radioactive waste generated, and improving on-site work efficiency.

[0007] The technical solution of the present invention is as follows:

[0008] An automatic device for removing radioactive contaminants from a valve chamber, comprising a movable trolley, a filter, a fluid transmission pump, a mechanical arm and a connecting pipe;

[0009] A filter and a filter shielding shell are arranged on the left side of the middle of the movable trolley, the filter is arranged inside the filter shielding shell, and a filter shielding shell cover is arranged on the upper part of the filter shielding shell;

[0010] A fluid transmission pump is provided on the right side of the middle of the movable trolley, and the fluid transmission pump is fixed inside the movable trolley through a bracket; the filter and the fluid transmission pump are connected through a pipe c, and the right end of the pipe c is connected to the sewage outlet through a valve a;

[0011] A pipeline a is arranged above the inside of the movable trolley, the upper right end of the pipeline a is connected to the quick connector female connector a through a valve b, a tee a and a tee a are arranged in the middle of the pipeline a, the lower part of the tee a is connected to the pipeline c, the upper part of the tee b is connected to the pipeline b, and the left end of the pipeline a is connected to the quick connector female connector b through a valve d;

[0012] The robotic arm base is fixed on the top left side of the movable trolley, the robotic arm is fixed on the upper end of the robotic arm base, a pipe b is provided inside the robotic arm and the robotic arm base, a valve c is provided at the lower part of the pipe b, and a radiation-resistant camera and a quick-connect female connector c are provided at the front end of the robotic arm.

[0013] The quick connector female connector c at the front end of the mechanical arm is connected to the quick connector male connector a at the top of the water suction, dust suction and decontamination head, and the lower end of the water suction, dust suction and decontamination head is an opening.

[0014] The quick connector female connector c at the front end of the robot arm is connected to the quick connector male connector b at the top of the scrubbing and decontamination head. An ultrasonic generator is arranged in the middle of the scrubbing and decontamination head, and a brush is arranged at the bottom of the scrubbing and decontamination head.

[0015] The brush is detachable and replaceable.

[0016] The bottom of the movable trolley is provided with guide wheels.

[0017] The filter shielding housing cover is an openable cover.

[0018] The robot arm is a 3-degree-of-freedom robot arm.

[0019] A method for automatically removing radioactive contaminants from a valve chamber, comprising the following steps: step 1: after a maintenance worker opens a valve flange and removes a valve cover, a decontamination worker moves an automatic device for removing radioactive contaminants from a valve chamber to the vicinity of a valve to be decontaminated, arranges a waste liquid collection bucket at the outlet of a sewage outlet, closes valve a and valve c, opens valve a and valve b, connects a water suction and dust removal head to a quick-connect female joint at the front end of a multi-manipulator arm through a quick-connect male joint, starts a fluid transmission pump, and performs a pneumatic valve chamber automatic water suction and dust removal process to clean a radioactive solid-liquid mixture at the bottom of the valve chamber, and the radioactive solid-liquid mixture is discharged to the outside of the sewage outlet along the water suction and dust removal head, pipe b, tee b, pipe c, filter, and fluid transmission pump;

[0020] Step 2: After the first step of the automatic water suction and dust removal process of the valve chamber is completed, the decontamination personnel move the automatic radioactive dirt removal device of the valve chamber to a position away from the valve. After the maintenance personnel remove the valve disc, the decontamination personnel move the automatic radioactive dirt removal device of the valve chamber to a position close to the valve. The decontamination personnel remotely control the robotic arm, observe the dirt inside the valve chamber through the irradiation camera, connect the scrubbing and decontamination head to the quick connector female connector c at the front end of the robotic arm through the quick connector male connector b, turn on the ultrasonic generator, pneumatically perform the automatic valve chamber scrubbing and decontamination process, and perform the automatic water suction and dust removal process of the valve chamber in step 1 again to clean the residual dirt in the valve chamber after scrubbing and decontamination, and further reduce the radiation level in the valve chamber;

[0021] Step 3: After the automatic brushing and decontamination process of the valve cavity and the second automatic water suction and dust removal process of the valve cavity are completed, the decontamination personnel move the automatic radioactive dirt removal device of the valve cavity to a position away from the valve. After the maintenance personnel perform the grinding of the valve seat sealing surface, the decontamination personnel move the automatic radioactive dirt removal device of the valve cavity to a position close to the valve, replace a clean brush, connect the brushing and decontamination head to the quick connector female connector c at the front end of the robot arm through the quick connector male connector b, turn on the ultrasonic generator, and the decontamination personnel perform the automatic cleaning and decontamination process of the valve seat sealing surface on the remote centralized console, and perform the automatic water suction and dust removal process of the valve cavity in step 1 again to clean the metal particles on the surface of the valve seat sealing surface;

[0022] Step 4: The decontamination personnel use the radiation-resistant camera at the front end of the robotic arm to monitor the decontamination status on the remote centralized console. Once an abnormality is found, emergency operation is performed to stop the decontamination work;

[0023] Step 5: If the internal structure of the valve cavity is complex or the automatic decontamination procedure is not completely decontaminated, the decontamination personnel will control the robotic arm on the remote centralized console to perform remote decontamination, and observe the decontamination status through the radiation-resistant camera at the front end of the robotic arm;

[0024] Step 6: During the decontamination of the valve cavity, radioactive substances may be deposited in the pipes and valves of the automatic device for removing radioactive contaminants from the valve cavity of the present invention. The relevant pipes and valves may be flushed and decontaminated. The specific method is as follows:

[0025] Open valve a and valve b, close valve c and valve d, connect the external flushing pipe with the quick connector male joint to the quick connector female joint a8, and flush and decontaminate pipe a, pipe c, filter, fluid transfer pump, and valve a;

[0026] Open valve b and valve c, close valve a and valve d, connect the external flushing pipe with the quick connector male joint to the quick connector female joint a, and flush and decontaminate pipe a, pipe b, and valve c;

[0027] Open valve b and valve d, close valve a and valve c, connect the external flushing pipe with the quick connector male joint to the quick connector female joint a, and flush and decontaminate pipe a and valve d.

[0028] In step five, when automatic decontamination is difficult to perform due to limited space at the valve installation location and small valve size, the decontamination personnel use a hose with quick-connect male and female connectors at both ends to connect the water suction and dust removal head with the quick-connect female connector, close valve b and valve c, open valve a and valve d, start the fluid transfer pump, hold the water suction and dust removal head to perform manual water suction and dust removal, and hold the brushing decontamination head to perform manual brushing decontamination.

[0029] The beneficial effects of the present invention are:

[0030] Using the automatic valve chamber radioactive contamination removal device to replace manual decontamination work inside the valve chamber can effectively reduce the radiation dose of decontamination personnel and maintenance personnel, improve the decontamination effect and decontamination efficiency, remove the radioactive contamination in the valve chamber and the metal particles generated by grinding, reduce the radiation dose of maintenance personnel and reduce the radiation source of the unit, while reducing the amount of radioactive waste generated and the radiation exposure of radioactive waste to workers, as follows:

[0031] (1) The automatic device for removing radioactive contaminants from the valve chamber replaces humans in carrying out the decontamination work inside the valve chamber. After the decontamination personnel complete the equipment installation near the valve to be decontaminated, the decontamination is automatically carried out. The decontamination personnel remotely monitor the decontamination process through a camera, which significantly reduces the radiation exposure of the decontamination personnel and avoids the decontamination personnel being exposed to a high dose during the decontamination process;

[0032] (2) The automatic device for removing radioactive contaminants from the valve chamber can perform decontamination operations for a long time, and use a variety of decontamination heads to carry out targeted decontamination of different parts (including the bottom of the valve chamber and the sealing surface of the valve seat) and different radioactive materials (including solid and liquid radioactive materials), significantly improving the decontamination effect and efficiency. It solves the problems of limited decontamination time (the working time of personnel must be limited in a high-radiation environment) and poor decontamination effect and low decontamination efficiency caused by the use of simple methods such as rags. Through efficient decontamination, the radiation level in the valve chamber is reduced, thereby reducing the radiation dose of valve maintenance personnel. At the same time, by removing the cobalt (Co-59) metal particles generated by valve seat grinding, the metal particles are prevented from being activated by the core and increasing the radiation source of the unit;

[0033] (3) The automatic radioactive waste removal device for the valve chamber uses a built-in filter to filter solid and liquid radioactive substances, and a radiation shielding device is set on the filter, avoiding the consumption of existing manual decontamination cloths and other materials, reducing the amount of radioactive waste generated, and at the same time reducing the radiation exposure of radioactive waste to other workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of the automatic device for removing radioactive contaminants from a valve chamber of the present invention;

[0035] In the figure: 1. guide wheel of the mobile trolley; 2. the mobile trolley; 3. the bracket; 4. the sewage outlet; 5. the valve a; 6. the fluid transmission pump; 7. the valve b; 8. the quick connector female connector a; 9. the filter shielding shell cover; 10. the pipe a; 11. the tee a; 12. the tee b; 13. the pipe b; 14. the mechanical arm; 15. the mechanical arm base; 16. the valve c; 17. the valve d; 18. the quick connector female connector b; 19. the camera; 20. the quick connector female connector c; 21. the quick connector male connector a; 22. the water suction and dust removal head; 23. the quick connector male connector b; 24. the brushing and cleaning head; 25. the ultrasonic generator; 26. the brush; 27. the pipe c; 28. the filter; 29. ​​the filter shielding shell. DETAILED DESCRIPTION

[0036] 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.

[0037] Figure 1The valve chamber radioactive contaminant automatic removal device shown in the figure has a guide wheel 1 at the bottom of a movable trolley 2, a filter 28 and a filter shielding shell 29 are provided on the left side of the middle of the movable trolley, the filter 28 is arranged inside the filter shielding shell 29, and a filter shielding shell cover plate 9 is arranged on the upper part of the filter shielding shell 29, and the filter shielding shell cover plate 9 is an openable cover plate;

[0038] A fluid transfer pump 6 is provided on the right side of the middle of the movable trolley 2, and the fluid transfer pump 6 is fixed inside the movable trolley 2 through a bracket 3; the filter 28 and the fluid transfer pump 6 are connected through a pipe c27, and the right end of the pipe c27 is connected to the sewage outlet 4 through a valve a5;

[0039] A pipe a10 is arranged above the movable trolley 2, the upper right end of the pipe a10 is connected to a quick connector female joint a8 through a valve b7, a tee a11 and a tee a12 are arranged in the middle of the pipe a10, wherein the lower part of the tee a11 is connected to the pipe c27, the upper part of the tee b12 is connected to the pipe b13, and the left end of the pipe a10 is connected to a quick connector female joint b18 through a valve d17;

[0040] The robot base 15 is fixed to the top left side of the movable trolley 1. The robot arm 14 is a 5-DOF robot arm, which is fixed to the upper end of the robot arm base 15. A pipe b13 is provided inside the robot arm 14 and the robot arm base 15. A valve c16 is provided at the lower part of the pipe b13. A radiation-resistant camera 19 and a quick-connect female connector c20 are provided at the front end of the robot arm 14.

[0041] The quick connector male connector a21 at the top of the water suction dust removal head 22 can be connected to the quick connector female connector c20 at the front end of the robot arm 14, and the lower end of the water suction dust removal head 22 is an opening;

[0042] The quick connector male connector b23 at the top of the scrubbing and decontamination head 24 can be connected to the quick connector female connector c20 at the front end of the robot arm 14. An ultrasonic generator 25 is provided in the middle of the scrubbing and decontamination head 24. The lower part of the scrubbing and decontamination head 24 is a brush 26, which can be removed and replaced.

[0043] Accordingly, the method of using the decontamination device of the present invention is as follows:

[0044] 1) After the maintenance personnel open the valve flange and remove the valve cover, the decontamination personnel move the valve chamber radioactive waste automatic removal device of the present invention to the vicinity of the valve to be decontaminated, arrange a waste liquid collection bucket at the outlet of the sewage outlet 4, close valve a7 and valve c17, open valve a5 and valve b16, connect the water suction and dust removal head 22 to the quick connector female connector 20 at the front end of the multi-mechanical arm 14 through the quick connector male connector 21, start the fluid transmission pump 6, and the decontamination personnel perform the pre-set valve chamber automatic water suction and dust removal program a on the remote centralized control console (not shown in the figure) to clean the radioactive solid and liquid mixture at the bottom of the valve chamber. The radioactive solid and liquid mixture is discharged to the outside of the sewage outlet 4 along the water suction and dust removal head 22, the pipe b13, the tee b12, the pipe c27, the filter 28, and the fluid transmission pump 6. By cleaning the radioactive solid and liquid mixture at the bottom of the valve chamber, the radiation level in the valve chamber is reduced, and a water-free environment is created for the maintenance personnel to remove the valve disc later.

[0045] 2) After the valve cavity automatic water suction and dust removal procedure a is completed, the decontamination personnel moves the valve cavity radioactive dirt automatic removal device of the present invention to a position away from the valve. After the maintenance personnel remove the valve disc, the decontamination personnel moves the valve cavity radioactive dirt automatic removal device of the present invention to a position close to the valve. The decontamination personnel remotely controls the robotic arm 14, observes the dirt inside the valve cavity through the irradiation camera 20, connects the scrubbing and decontamination head 24 to the quick connector female connector c20 at the front end of the robotic arm 14 through the quick connector male connector b23, turns on the ultrasonic generator 25, and the decontamination personnel executes the valve cavity automatic scrubbing and decontamination procedure b on the remote centralized control console, and executes the valve cavity automatic water suction and dust removal procedure a in step 1) again to clean the residual dirt after the valve cavity is scrubbed and decontaminated, further reduce the radiation level in the valve cavity, and reduce the exposure dose of subsequent maintenance personnel performing valve grinding work.

[0046] 3) After the valve cavity automatic brushing and decontamination procedure b and the second valve cavity automatic water suction and dust removal procedure a are completed, the decontamination personnel move the valve cavity radioactive dirt automatic removal device of the present invention to a position away from the valve. After the maintenance personnel perform the valve seat sealing surface grinding, the decontamination personnel move the valve cavity radioactive dirt automatic removal device of the present invention to a position close to the valve, replace a clean brush 26, connect the brushing and decontamination head 24 to the quick connector female connector c20 at the front end of the robot arm 14 through the quick connector male connector b23, turn on the ultrasonic generator 25, and the decontamination personnel perform the valve seat sealing surface automatic cleaning and decontamination procedure c on the remote centralized control console, and perform the valve cavity automatic water suction and dust removal procedure a in step 1) again to clean the metal particles on the surface of the valve seat sealing surface to prevent the metal particles from being subsequently activated by the core.

[0047] 4) The decontamination personnel monitor the decontamination status on the remote centralized control console using the radiation-resistant camera 19 at the front end of the robotic arm 14. Once an abnormality is found, emergency operation is performed to stop the decontamination work.

[0048] 5) For the case where the internal structure of the valve cavity is complex or the automatic decontamination procedure is not completely decontaminated, the decontamination personnel will control the robot arm 14 on the remote centralized control console to perform remote decontamination, and observe the decontamination status through the radiation-resistant camera 19 at the front end of the robot arm 14. In addition, when it is difficult to perform automatic decontamination due to limited space at the valve installation location and small valve size, the decontamination personnel will use a hose with a quick connector male connector and a female connector at both ends to connect the water suction and dust removal head 22 with the quick connector female connector 18, close valve b8 and valve c16, open valve a5 and valve d17, start the fluid transmission pump 6, hold the water suction and dust removal head 22 to perform manual water suction and dust removal, and hold the brush cleaning head 24 to perform manual brush cleaning.

[0049] 6) During the decontamination process of the valve cavity, radioactive substances may be deposited in the pipes and valves of the automatic removal device for radioactive contaminants in the valve cavity of the present invention. The relevant pipes and valves may be flushed and decontaminated. The specific method is as follows:

[0050] Open valve a5 and valve b7, close valve c16 and valve d17, connect the external flushing pipe with the quick connector male connector to the quick connector female connector a8, and flush and decontaminate pipe a10, pipe c27, filter 28, fluid transfer pump 6, and valve a5;

[0051] Open valve b7 and valve c16, close valve a5 and valve d17, connect the external flushing pipe with the quick connector male joint to the quick connector female joint a8, and flush and decontaminate pipe a10, pipe b13, and valve c16;

[0052] Open valve b7 and valve d17, close valve a5 and valve c16, connect the external flushing pipe with the quick connector male joint to the quick connector female joint a8, and flush and decontaminate the pipe a10 and valve d17.

[0053] In the drawings of the embodiments disclosed in the present invention, only the methods related to the embodiments disclosed in the present invention are involved, and other methods can refer to the general design. In the case of no conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic device for removing radioactive contaminants from a valve chamber, comprising a movable trolley, a filter, a fluid transmission pump, a mechanical arm and a connecting pipe; Features: A filter and a filter shielding shell are provided on the left side of the middle of the movable trolley, the filter is arranged inside the filter shielding shell, and a filter shielding shell cover is arranged on the upper part of the filter shielding shell; A fluid transmission pump is provided on the right side of the middle of the movable trolley, and the fluid transmission pump is fixed inside the movable trolley through a bracket; the filter and the fluid transmission pump are connected through a pipe c, and the right end of the pipe c is connected to the sewage outlet through a valve a; A pipeline a is arranged above the inside of the movable trolley, the upper right end of the pipeline a is connected to the quick connector female connector a through a valve b, a tee a and a tee a are arranged in the middle of the pipeline a, the lower part of the tee a is connected to the pipeline c, the upper part of the tee b is connected to the pipeline b, and the left end of the pipeline a is connected to the quick connector female connector b through a valve d; The robot arm base is fixed on the top left side of the movable trolley, the robot arm is fixed on the upper end of the robot arm base, a pipe b is provided inside the robot arm and the robot arm base, a valve c is provided at the lower part of the pipe b, and a radiation-resistant camera and a quick-connect female connector c are provided at the front end of the robot arm; The quick connector female connector c at the front end of the robot arm is connected to the quick connector male connector a at the top of the water suction, dust suction and decontamination head, and the lower end of the water suction, dust suction and decontamination head is open; The quick connector female connector c at the front end of the robot arm is connected to the quick connector male connector b at the top of the scrubbing and decontamination head. An ultrasonic generator is arranged in the middle of the scrubbing and decontamination head, and a brush is arranged at the bottom of the scrubbing and decontamination head.

2. The automatic device for removing radioactive contaminants from a valve chamber as claimed in claim 1, characterized in that: The brush is detachable and replaceable.

3. An automatic device for removing radioactive contaminants from a valve chamber according to any one of claims 1 or 2, characterized in that: The bottom of the movable trolley is provided with guide wheels.

4. The automatic device for removing radioactive contaminants from a valve chamber according to any one of claims 1 or 2, characterized in that: The filter shielding housing cover is an openable cover.

5. The automatic device for removing radioactive contaminants from a valve chamber according to any one of claims 1 or 2, characterized in that: The robot arm is a 3-degree-of-freedom robot arm.

6. A method for automatically removing radioactive contaminants from a valve chamber using the device of claim 1, characterized in that: Step 1: After the maintenance personnel open the valve flange and remove the valve cover, the decontamination personnel move the automatic radioactive contamination removal device of the valve chamber to the vicinity of the valve to be decontaminated, arrange the waste liquid collection bucket at the outlet of the sewage outlet, close valve a and valve c, open valve a and valve b, connect the water suction and dust removal head to the quick connector female connector at the front end of the multi-manipulator arm through the quick connector male connector, start the fluid transmission pump, and pneumatically operate the automatic water suction and dust removal process of the valve chamber to clean the radioactive solid and liquid mixture at the bottom of the valve chamber. The radioactive solid and liquid mixture is discharged to the outside of the sewage outlet along the water suction and dust removal head, pipe b, tee b, pipe c, filter, and fluid transmission pump; Step 2: After the first step of the automatic water suction and dust removal process of the valve chamber is completed, the decontamination personnel move the automatic radioactive dirt removal device of the valve chamber to a position away from the valve. After the maintenance personnel remove the valve disc, the decontamination personnel move the automatic radioactive dirt removal device of the valve chamber to a position close to the valve. The decontamination personnel remotely control the robotic arm, observe the dirt inside the valve chamber through the irradiation camera, connect the scrubbing and decontamination head to the quick connector female connector c at the front end of the robotic arm through the quick connector male connector b, turn on the ultrasonic generator, pneumatically perform the automatic valve chamber scrubbing and decontamination process, and perform the automatic water suction and dust removal process of the valve chamber in step 1 again to clean the residual dirt in the valve chamber after scrubbing and decontamination, and further reduce the radiation level in the valve chamber; Step 3: After the automatic brushing and decontamination process of the valve cavity and the second automatic water suction and dust removal process of the valve cavity are completed, the decontamination personnel move the automatic radioactive dirt removal device of the valve cavity to a position away from the valve. After the maintenance personnel perform the grinding of the valve seat sealing surface, the decontamination personnel move the automatic radioactive dirt removal device of the valve cavity to a position close to the valve, replace a clean brush, connect the brushing and decontamination head to the quick connector female connector c at the front end of the robot arm through the quick connector male connector b, turn on the ultrasonic generator, and the decontamination personnel perform the automatic cleaning and decontamination process of the valve seat sealing surface on the remote centralized console, and perform the automatic water suction and dust removal process of the valve cavity in step 1 again to clean the metal particles on the surface of the valve seat sealing surface; Step 4: The decontamination personnel use the radiation-resistant camera at the front end of the robotic arm to monitor the decontamination status on the remote centralized console. Once an abnormality is found, emergency operation is performed to stop the decontamination work; Step 5: If the internal structure of the valve cavity is complex or the automatic decontamination procedure is not completely decontaminated, the decontamination personnel will control the robotic arm on the remote centralized console to perform remote decontamination, and observe the decontamination status through the radiation-resistant camera at the front end of the robotic arm; Step 6: During the decontamination process of the valve cavity, radioactive substances are deposited in the pipes and valves of the automatic removal device for radioactive contaminants in the valve cavity. The relevant pipes and valves can be flushed and decontaminated. The specific method is as follows: Open valve a and valve b, close valve c and valve d, connect the external flushing pipe with the quick connector male joint to the quick connector female joint a8, and flush and decontaminate pipe a, pipe c, filter, fluid transfer pump, and valve a; Open valve b and valve c, close valve a and valve d, connect the external flushing pipe with the quick connector male joint to the quick connector female joint a, and flush and decontaminate pipe a, pipe b, and valve c; Open valve b and valve d, close valve a and valve c, connect the external flushing pipe with the quick connector male joint to the quick connector female joint a, and flush and decontaminate pipe a and valve d.

7. A method for automatically removing radioactive contaminants from a valve chamber as claimed in claim 6, characterized in that: In step five, when automatic decontamination is difficult to perform due to limited space at the valve installation position and valve size, the decontamination personnel use a hose with a quick-connect male connector and a female connector at both ends to connect the water suction and dust removal head with the quick-connect female connector, close valve b and valve c, open valve a and valve d, start the fluid transfer pump, hold the water suction and dust removal head to perform manual water suction and dust removal, and hold the brushing decontamination head to perform manual brushing decontamination.

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