Radioactive metal waste underwater laser cutting apparatus and cutting method

Abstract

The application discloses a radioactive metal waste underwater laser cutting device, which comprises a cutting pool, a laser cutting assembly, a water injection assembly, a water drainage assembly, an air cover and a pressure control assembly, the water injection assembly is used for injecting water into the cutting pool, the water drainage assembly is used for draining water in the cutting pool, the air cover is located in the cutting pool, and the pressure control assembly is used for controlling the air pressure in the air cover and making the liquid level in the air cover lower than the liquid level outside the air cover. The radioactive metal waste underwater laser cutting device can realize laser cutting in the case that water is used as a shielding material, and can greatly reduce the dose level of a working environment; the device has aerosol collection, filtration and absorption functions, so that the aerosol is not discharged outside, and the device can realize remote automatic cutting.

Description

Technical Field

[0001] This invention belongs to the field of radioactive metal cutting technology, and particularly relates to an underwater laser cutting device for radioactive metal waste and a method for underwater laser cutting of radioactive metal waste using the cutting device. Background Technology

[0002] In nuclear power plant decommissioning projects, large radioactive metal components need to be cut and prepared to reduce space occupancy and achieve the goal of reducing waste disposal volume. Radioactive metal components from decommissioned and scrapped nuclear power plants are characterized by their large size and high radiation dose.

[0003] Continuous laser cutting is a high-energy cutting method with long focal length and depth of focus, offering advantages such as large cutting thickness, narrow kerf, small cutting equipment size, and automation. However, its application in nuclear power plant decommissioning projects has the following drawbacks:

[0004] (1) The cutting thickness is thick, up to 500mm, but the corresponding focal length is 2-3m, so a large space is required; (2) The radioactive aerosol generated after laser cutting needs to be filtered and absorbed to avoid polluting the working environment; (3) The laser has a high energy density, so physical barriers should be avoided during the cutting process to prevent the laser from accidentally cutting personnel and equipment. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an underwater laser cutting device suitable for underwater radioactive metal waste, which enables underwater laser cutting of workpieces.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An underwater laser cutting device for radioactive metal waste includes a cutting pool, a laser cutting assembly, a water injection assembly, a drainage assembly, an air hood, and a pressure control assembly. The water injection assembly injects water into the cutting pool; the drainage assembly drains water from the cutting pool; the air hood is located inside the cutting pool; and the pressure control assembly controls the air pressure inside the air hood to ensure that the liquid level inside the air hood is lower than the liquid level outside the air hood. The lower liquid level inside the air hood enables laser cutting; the higher liquid level outside the air hood allows water to form a shield. Both the air hood and the cutting pool are circular or square.

[0008] According to some preferred embodiments of the present invention, the pressure control assembly includes an injection mechanism for supplying gas into the gas hood, the injection mechanism including an inlet pipe communicating with the interior of the gas hood, a fan disposed on the inlet pipe, and an inlet check valve. Multiple inlets may be provided between the inlet pipe of the injection mechanism and the gas hood, connected by a circular flange and rubber sealing gasket.

[0009] According to some preferred embodiments of the invention, the pressure control assembly includes an exhaust mechanism for discharging gas from inside the gas hood to the outside, the exhaust mechanism including an exhaust pipe communicating with the inside of the gas hood, an exhaust check valve disposed on the exhaust pipe, and an aerosol filter.

[0010] According to some preferred embodiments of the present invention, the outlet check valve is preferably a pressure regulating valve, which is signal-connected to the fan, enabling the pressure regulating valve to control the operation of the fan according to the pressure inside the hood. This achieves upstream pressure maintenance on one hand; on the other hand, when the upstream pressure exceeds a set value, the pressure regulating valve opens, automatically initiating exhaust.

[0011] According to some preferred embodiments of the invention, a protective plate is provided inside the cutting pool, the protective plate being positioned between the workpiece to be cut and the gas hood to protect the gas hood. The protective plate is used to block the laser emitted from the laser, and its thickness is set to 40mm to 100mm.

[0012] According to some preferred embodiments of the present invention, the water injection assembly includes a water injection pipe and a water injection pump disposed on the water injection pipe, one end of the water injection pipe being connected to the space between the outer wall of the air hood and the inner wall of the cutting pool.

[0013] According to some preferred embodiments of the invention, the drainage assembly includes a drain pipe, a filter, a dose monitor, and a drain valve arranged sequentially on the drain pipe.

[0014] According to some preferred embodiments of the invention, a water circulation assembly is included, comprising a circulation pump disposed on the drain pipe, a circulation water pipe communicating with the cutting pool and the drain pipe, and a circulation water valve disposed on the circulation water pipe. The connection between the circulation water pipe and the drain pipe is located between the circulation pump and the drain valve.

[0015] According to some preferred embodiments of the present invention, the laser cutting assembly includes a laser controller, a laser generator, a laser cutting head, and an optical fiber located between the laser generator and the laser cutting head; the laser cutting head is located within the cutting pool, and the gas shroud is located above the laser cutting head and the workpiece to be cut.

[0016] According to some preferred embodiments of the present invention, the cutting pool is provided with a displacement mechanism for controlling the position of the laser cutting head, the displacement mechanism including a movable seat and a telescopic platform disposed on the movable seat, the laser cutting head being disposed on the telescopic platform.

[0017] According to some preferred embodiments of the invention, a support mechanism is included, along with a movable lifting device and a gripping mechanism disposed on the support mechanism, the movable lifting device being used to control the position of the air hood, and the gripping mechanism being used to grip the workpiece to be cut or the workpiece after cutting.

[0018] The present invention also provides a cutting method based on the above-mentioned underwater laser cutting device for radioactive metal waste, comprising the following steps:

[0019] Drain the water from the cutting pool and place the workpiece to be cut into the cutting pool; move the laser cutting head to the appropriate cutting position;

[0020] Move the gas hood into the cutting pool and position it above the laser cutting head and the workpiece to be cut; then move the gas hood downwards to the appropriate position.

[0021] Gas is continuously injected into the gas hood through the gas injection mechanism; at the same time, water is injected into the cutting pool by activating the water injection component.

[0022] The pressure control mechanism controls the air pressure inside the gas hood and ensures that the liquid level inside the gas hood is lower than the liquid level outside the gas hood, thus ensuring that the liquid level inside the gas hood is lower than the laser emission and cutting path for laser cutting.

[0023] Due to the adoption of the above technical solutions, the advantages of the present invention compared with the prior art are as follows: the underwater laser cutting device for radioactive metal waste of the present invention can achieve laser cutting with water as the shielding material, which greatly reduces the dose level in the working environment; the device has aerosol collection, filtration and absorption functions to ensure that aerosols are not released, and the device can realize remote automated cutting. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the underwater laser cutting device in a preferred embodiment of the present invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] The reference numerals and brief descriptions of the components in the attached drawings are shown in Table 1 below:

[0028] Table 1. Figure Labels and Brief Descriptions

[0029]

[0030]

[0031]

[0032] Example 1: Underwater Laser Cutting Device

[0033] like Figure 1 As shown, the underwater laser cutting device of this embodiment includes a cutting pool 10, a laser cutting assembly, a water injection assembly, a drainage assembly, a water circulation assembly, an air hood 31, a pressure control assembly, a support mechanism 40, and a movable lifting device 30 and a gripping mechanism mounted on the support mechanism 40. The movable lifting device 30 is used to control the position of the air hood 31, and the gripping mechanism includes a crane 41 and a gripper 42 for gripping the workpiece 50 to be cut or the cut workpiece. The cutting pool 10 has a support platform 11, and the workpiece 50 to be cut is placed on the support platform 11 by the gripping mechanism.

[0034] The structure and function of each component are described below.

[0035] The laser cutting assembly includes a laser controller 25, a laser generator 24, a laser cutting head 20, and an optical fiber 26 located between the laser generator 24 and the laser cutting head 20. The laser cutting head 20 is located within the cutting pool 10, and the gas shroud 31 is located above the laser cutting head 20 and the workpiece 50 to be cut. The laser cutting head 20 faces the space in front of the emitted laser, and the direction of the laser cutting head can be tilted upwards or downwards, with the angle between the upward tilt limit position and the downward tilt limit position being 90°.

[0036] The cutting pool 10 is equipped with a displacement mechanism for controlling the position of the laser cutting head 20. The displacement mechanism includes a movable base 22 and a telescopic platform 21 mounted on the movable base 22. The laser cutting head 20 is mounted on the telescopic platform 21. Rollers 23 are provided below the movable base 22.

[0037] A protective plate 12 is installed inside the cutting pool 10, located between the workpiece 50 to be cut and the air hood 31, to protect the air hood 31. In order to monitor the cutting status of the underwater cutting operation, an underwater television 13 is also installed inside the cutting pool.

[0038] The water injection assembly is used to inject water into the cutting pool 10. The water injection assembly includes a water injection pipe and a water injection pump 17B installed on the water injection pipe. One end of the water injection pipe is connected to the space between the outer wall of the air hood 31 and the inner wall of the cutting pool 10.

[0039] The drainage assembly is used to drain water from the cutting pool 10. The drainage assembly includes a drain pipe 14, a filter 15, a dose monitor 16, and a drain valve 19B, which are sequentially arranged on the drain pipe 14. In this embodiment, an isolation water valve 19C is also provided on the drain pipe.

[0040] The water circulation assembly includes a circulation pump 17A mounted on the drain pipe 14, a circulation water pipe 18 connecting the cutting pool 10 and the drain pipe 14, and a circulation water valve 19A mounted on the circulation water pipe. The connection between the circulation water pipe and the drain pipe is located between the circulation pump and the drain valve.

[0041] The gas hood 31 is located within the cutting pool 10. A pressure control assembly controls the gas pressure within the gas hood 31, ensuring the liquid level inside the gas hood 31 is lower than the liquid level outside. The lower liquid level inside the gas hood facilitates laser cutting; the higher liquid level outside the gas hood allows for the formation of a water shield. The pressure control assembly includes an injection mechanism for supplying gas into the gas hood 31 and an exhaust mechanism for discharging gas from the gas hood 31 to the outside.

[0042] The air injection mechanism includes an air inlet pipe 34 communicating with the inside of the air hood 31, a fan 36 mounted on the air inlet pipe 34, and an air inlet check valve 32. The exhaust mechanism includes an exhaust pipe 35 communicating with the inside of the air hood 31, an exhaust outlet check valve mounted on the exhaust pipe 35, and an aerosol filter 37. The exhaust outlet check valve is preferably a pressure regulating valve 33, which is signal-connected to the fan 36, allowing the pressure regulating valve 33 to control the operation of the fan 36 according to the pressure inside the air hood 31. This achieves upstream pressure maintenance; furthermore, when the upstream pressure exceeds a set value, the pressure regulating valve 33 opens, automatically initiating exhaust.

[0043] Example 2: Underwater Laser Cutting Method

[0044] This embodiment provides a cutting method based on the above-mentioned underwater laser cutting device for radioactive metal waste, including the following steps: draining the water in the cutting pool and placing the workpiece to be cut in the cutting pool; moving the laser cutting head to a suitable cutting position; moving the gas hood into the cutting pool and positioning it above the laser cutting head and the workpiece to be cut, and moving the gas hood downward to a suitable position; continuously injecting gas into the gas hood through the gas injection mechanism; simultaneously, starting the water injection component to inject water into the cutting pool; controlling the gas pressure in the gas hood through the pressure control mechanism to ensure that the liquid level in the gas hood is lower than the liquid level outside the gas hood, ensuring that the liquid level in the gas hood is lower than the laser emission and cutting path, and performing laser cutting.

[0045] The underwater laser cutting method in this embodiment specifically includes the following steps:

[0046] I. Preparation steps:

[0047] 1) Drain the water in the cutting pool 10 through the drainage assembly.

[0048] 2) Use crane 41 and gripper 42 to place the workpiece 50 to be cut onto support platform 11.

[0049] 3) Once the laser cutting assembly is in place, the remote start roller 23 moves the moving seat 22 to the specified position. Based on the distance requirements for laser cutting, the distance between the laser cutting head 20 and the workpiece 50 to be cut is determined.

[0050] 4) Use crane 41 and gripper 42 to lift the guard plate 12 and place it behind the workpiece 50 to be cut and in front of the inner wall of the air hood.

[0051] 5) Use the mobile lifting device 30 to lift the air cover and pressure control components (31-37) into the cutting pool, and gradually lower them to confirm through video monitoring (underwater TV) that the air cover 31 covers the laser cutting head 20 and the workpiece 50 to be cut.

[0052] 6) Start the fan 36 to continuously inject air into the air hood 31;

[0053] 7) Start the water pump 17B to inject water into the cutting pool, so that there is a certain pressure of air in the upper part of the air hood 31. The water level in the air hood gradually rises until it reaches the preset pressure of the pressure regulating valve 33, at which point the water level stabilizes at a certain height. The water level in the air hood is ensured to not obstruct the laser emission and cutting path.

[0054] The pressure regulating valve 33 can monitor the upstream pressure. If the upstream pressure is too low, it can send a signal to control the blower 36 to start and blow gas into the air hood. At the same time, if the upstream pressure is too high, the pressure regulating valve opens and automatically vents gas to achieve pressure control.

[0055] II. Cutting steps:

[0056] 8) Operate the laser controller 25, start the laser generator 24, adjust the laser parameters to the predetermined value, operate the laser controller 25 to make the laser cutting head 20 emit laser light and cut the predetermined position of 50.

[0057] 9) The guard plate 12 blocks the laser beam projected from the cut of the cutting part 50 during cutting, and the protective gas shield 31.

[0058] 10) During the cutting process, if a certain amount of flue gas accumulates in the gas hood 31, the remote control regulating valve 33 will open to exhaust the gas. After exhaust, the pressure inside the gas hood 31 will drop, and the fan 36 will automatically start to blow air into the gas hood 31, thus realizing the ventilation function.

[0059] 11) Turn on water pump 17A and water valve 19A to circulate the water in pool 10 and purify the water.

[0060] III. 15 Steps to Replace the Filter:

[0061] 1) If the dose monitor 16 alarms during the cutting process, the cutting operation will be stopped and the water pump 17A will be stopped.

[0062] 2) Close water valves 19A, 19B, and 19C.

[0063] 3) Replace with a new filter 15.

[0064] 4) Open water valves 19A and 19C, turn on water pump 17A, and continue cutting operations.

[0065] IV. Drainage steps for the cutting pool after the cutting operation is completed:

[0066] 1) Close water valve 19A and open water valve 19B.

[0067] 2) Start water pump 17A and discharge water from the cutting pool through water valve 19B.

[0068] 3) After the water has been drained, close water valves 19A, 19B, and 19C.

[0069] For ease of description and understanding, the above steps are numbered and described separately, but there is no limiting meaning. In practice, some or all of the above steps can be performed simultaneously or in no particular order.

[0070] Compared with conventional dry environment flame cutting of radioactive metals, the device and method of the present invention for underwater laser cutting of radioactive metal waste have the following advantages: (1) Continuous laser enables remote automated cutting. (2) It can cut metals up to 500 mm thick, and the material range is relatively limited, including stainless steel, carbon steel, alloy steel, etc. (3) The device has aerosol collection, filtration, and absorption functions to ensure that aerosols are not released. (4) The water body has a radioactive shielding function, which greatly reduces the dose level in the working environment.

[0071] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A cutting method for an underwater laser cutting device for radioactive metal waste, characterized in that, This is performed using an underwater laser cutting device for radioactive metal waste. The device includes a cutting pool, a laser cutting assembly, a water injection assembly, a drainage assembly, an air hood, and a pressure control assembly. The water injection assembly is used to inject water into the cutting pool, and the drainage assembly is used to drain the water from the cutting pool. The air hood is located inside the cutting pool, and the pressure control component is used to control the air pressure inside the air hood and make the liquid level inside the air hood lower than the liquid level outside the air hood. The pressure control assembly includes an injection mechanism for supplying gas into the gas hood, the injection mechanism including an inlet pipe communicating with the inside of the gas hood and a fan mounted on the inlet pipe; the pressure control assembly also includes an exhaust mechanism for discharging gas from the gas hood to the outside, the exhaust mechanism including an exhaust pipe communicating with the inside of the gas hood and an exhaust check valve mounted on the exhaust pipe; the exhaust check valve is signal-connected to the fan, and the exhaust check valve controls the operation of the fan according to the pressure inside the gas hood; The cutting method includes the following steps: draining the water from the cutting pool, placing the workpiece to be cut in the cutting pool; and moving the laser cutting head to a suitable cutting position. Move the air hood into the cutting pool and position it above the laser cutting head and the workpiece to be cut. Move the air hood downwards to a suitable position. Continuously inject gas into the air hood through the gas injection mechanism. At the same time, activate the water injection component to inject water into the cutting pool, so that there is a certain pressure of air in the upper part of the air hood. The water level in the air hood gradually rises until it reaches the preset pressure of the gas outlet check valve. At this time, the water level stabilizes at a certain height. Control the air pressure in the air hood through the pressure control component and make the liquid level in the air hood lower than the liquid level outside the air hood. Ensure that the liquid level in the air hood is lower than the laser emission and cutting path, and perform laser cutting. During the cutting process, if smoke accumulates inside the hood, the remote control outlet check valve will open to exhaust the smoke. After exhaust, the pressure inside the hood will drop, and the fan will automatically start to blow air into the hood to achieve the ventilation function. The drainage assembly includes a drain pipe, a filter, a dose monitor, and a drain valve sequentially arranged on the drain pipe.

2. The cutting method according to claim 1, characterized in that, The air injection mechanism includes an air intake check valve installed on the air intake pipe.

3. The cutting method according to claim 1 or 2, characterized in that, The exhaust mechanism includes an aerosol filter disposed on the exhaust pipe.

4. The cutting method according to claim 3, characterized in that, The outlet check valve is a pressure regulating valve.

5. The cutting method according to claim 1, characterized in that, The cutting pool is equipped with a protective plate, which is located between the workpiece to be cut and the air hood to protect the air hood.

6. The cutting method according to claim 1, characterized in that, The water injection assembly includes a water injection pipe and a water injection pump mounted on the water injection pipe. One end of the water injection pipe is connected to the space between the outer wall of the air hood and the inner wall of the cutting pool.

7. The cutting method according to claim 1, characterized in that, The system includes a water circulation assembly, which includes a circulation pump mounted on the drain pipe, a circulation water pipe connecting the cutting pool and the drain pipe, and a circulation water valve mounted on the circulation water pipe.

8. The cutting method according to claim 1, characterized in that, The laser cutting assembly includes a laser controller, a laser generator, a laser cutting head, and an optical fiber located between the laser generator and the laser cutting head; the laser cutting head is located in the cutting pool, and the gas hood is located above the laser cutting head and the workpiece to be cut.

9. The cutting method according to claim 8, characterized in that, The cutting pool is equipped with a displacement mechanism for controlling the position of the laser cutting head. The displacement mechanism includes a movable base and a telescopic platform mounted on the movable base, and the laser cutting head is mounted on the telescopic platform.

10. The cutting method according to claim 1, characterized in that, It includes a support mechanism and a movable lifting device and a gripping mechanism mounted on the support mechanism. The movable lifting device is used to control the position of the air hood, and the gripping mechanism is used to grip the workpiece to be cut or the workpiece after cutting.

Images