Laser shearing method and cutting platform

Abstract

The embodiment of the invention provides a laser shearing method and a cutting platform. The laser shearing method is used for cutting an element rod of a fast reactor assembly and comprises the following steps that in the positioning stage, the element rod is pushed towards the side close to a baffle through a pushing assembly, and the end, close to the baffle, of the element rod makes contact with the baffle. And in the cutting stage, the laser cutting assembly is controlled to cut the element bar in the radial direction of the element bar. The laser shearing method provided by the embodiment of the invention is good in shearing effect.

Description

Technical Field

[0001] The present application relates to the field of laser cutting technology, and in particular to a laser shearing method and a cutting platform. Background Art

[0002] One of the key steps in fast neutron reactor (FWR) reprocessing is the shearing of FWR assemblies, which requires cutting the component rods in the spent fuel assembly into short segments of 2-5 cm.

[0003] In the step of shearing the element rods, the related technology uses mechanical shearing to shear the element rods. However, when facing the stainless steel cladding of the fast reactor component rods, the use of mechanical shearing may encounter risks such as severe deformation opening rate and severe tool wear after shearing, and there is a problem of poor shearing effect. Summary of the invention

[0004] In view of this, the main purpose of the embodiments of the present application is to provide a laser cutting method and a cutting platform with good shearing effect.

[0005] To achieve the above purpose, the technical solution of the embodiment of the present application is implemented as follows:

[0006] In a first aspect, an embodiment of the present application provides a laser cutting method for cutting a component rod of a fast reactor assembly. The laser cutting method includes a positioning stage and a cutting stage. The laser cutting method includes the following steps:

[0007] In the positioning stage, the element rod is pushed toward the side close to the baffle by the pushing assembly, so that the end of the element rod close to the baffle contacts the baffle;

[0008] During the cutting stage, the laser cutting assembly is controlled to cut the element rod along the radial direction of the element rod.

[0009] In one embodiment, in the positioning stage, after the end of the element rod close to the baffle contacts the baffle, the laser cutting method further comprises:

[0010] The pressure plate assembly is controlled to move toward the side close to the element rod so that the pressure plate assembly presses the element rod to limit the movement of the element rod.

[0011] In one embodiment, after the cutting stage, the laser shearing method further comprises:

[0012] Controlling the pressing plate assembly to move toward a side away from the element rod, so that the pressing plate assembly is separated from the element rod;

[0013] Control the pushing assembly to push the element rod again until it contacts the baffle, and control the pressing plate assembly to press the element rod again;

[0014] The laser cutting assembly is controlled to cut the element rod again.

[0015] In one embodiment, during the cutting stage, the laser cutting head of the laser cutting assembly is spaced apart from the element rod, and the distance between the laser cutting head and the element rod is 1 cm; and / or,

[0016] The fast reactor assembly comprises a plurality of the element rods, and during the cutting stage, the laser cutting assembly performs synchronous cutting on each of the element rods; and / or,

[0017] The fast reactor assembly includes a wire wound around the element rod. During the cutting stage, the laser cutting assembly synchronously cuts the element rod and the wire.

[0018] In one embodiment, the laser cutting assembly cuts the element rod at a cutting speed greater than or equal to 0.3 m / min and less than or equal to 1 m / min; and / or,

[0019] The focal position of the laser cutting assembly is greater than or equal to -25 mm and less than or equal to -15 mm; and / or,

[0020] The power of the laser cutting assembly is greater than or equal to 7200W and less than or equal to 12000W; and / or,

[0021] The auxiliary gas of the laser cutting assembly is one of nitrogen and air; and / or,

[0022] The air pressure of the laser cutting assembly is greater than or equal to 10 MPa and less than or equal to 18 MPa.

[0023] In one embodiment, the cutting speed is 0.3 m / min, the focal position is -20 mm, the power is 9600 W, the auxiliary gas is air, and the gas pressure is 15 MPa.

[0024] In one embodiment, the laser cutting and separation method further comprises the following steps:

[0025] The process parameters of the laser cutting assembly for cutting the element rod are determined by orthogonal experiment; wherein the experimental factors of the orthogonal experiment include at least one of the cutting speed, the focal position, the power, the auxiliary gas and the gas pressure.

[0026] In one embodiment, in the orthogonal test, alumina ceramics are used to replace the fuel in the element rod.

[0027] A second aspect of an embodiment of the present application provides a cutting platform for use in any of the above-mentioned laser shearing methods, wherein the cutting platform comprises a pushing assembly, a baffle and a laser cutting assembly, wherein the pushing assembly is used to push the element rod toward the side close to the baffle, and the laser cutting assembly is used to cut the element rod along the radial direction of the element rod.

[0028] In one embodiment, the cutting platform also includes a working space and a pressure plate assembly, wherein the working space is used to place the element rod, and the pressure plate assembly can be movably disposed on the top side of the working space, and the pressure plate assembly can be moved to switch between pressing the element rod and separating from the element rod.

[0029] The embodiment of the present application provides a laser shearing method and a cutting platform. The laser shearing method is used to cut the element rods of the fast reactor assembly, and includes the following steps: in the positioning stage, the element rod is pushed toward the side close to the baffle by the pushing assembly so that the end of the element rod close to the baffle contacts the baffle. In the cutting stage, the laser cutting assembly is controlled to cut the element rod along the radial direction of the element rod. The speed of cutting the element rod by laser is fast, the amount of secondary pollution waste and water is small, and there is no deformation or residual stress on the cutting surface, so the shearing effect is good. In addition, laser cutting uses optical fiber transmission, which can be applied to difficult-to-reach or highly radioactive areas. At the same time, its non-contact characteristics also extend the service life of the cutting tool, thereby further improving the cutting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a flowchart of a laser cutting method according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] An embodiment of the present application provides a laser cutting method for cutting element rods of a fast reactor assembly. The laser cutting method includes a positioning stage and a cutting stage. Figure 1 , the laser shearing method comprises the following steps:

[0032] Step S1: In the positioning stage, the component rod is pushed toward the side close to the baffle by the pushing assembly, so that the end of the component rod close to the baffle contacts the baffle.

[0033] Step S2: During the cutting stage, the laser cutting assembly is controlled to cut the element rod along the radial direction of the element rod.

[0034] Another embodiment of the present application provides a cutting platform for use in the laser shearing method described in any embodiment of the present application. The cutting platform includes a pushing assembly, a baffle and a laser cutting assembly. The pushing assembly is used to push the element rod toward the side close to the baffle, and the laser cutting assembly is used to cut the element rod along the radial direction of the element rod.

[0035] Specifically, laser technology has the characteristics of flexibility, high cutting efficiency, no contact between the laser cutting head and the material, and no stress deformation of the material during the cutting process. The use of laser technology can better match the complex cutting process and high precision requirements required for the shearing of component rods.

[0036] The type of laser cutting component can be set according to the actual situation. For example, the laser cutting component is a fiber solid laser. Fiber solid laser can play a considerable role in material processing, and can realize the shearing, welding and repair of various components of nuclear reactors, the manufacture of new components, and the decontamination and decommissioning of nuclear reactors.

[0037] It should be noted that the laser cutting method of the present application can be used to cut only one component rod of a fast reactor assembly, and of course it can also be used to cut multiple component rods of a fast reactor assembly simultaneously.

[0038] For example, a fast reactor assembly includes multiple element rods. During the cutting stage, the laser cutting assembly cuts each element rod synchronously. Thus, a row of element rods can be cut at a time, which can significantly reduce the laser cutting action and extend the life of the laser cutting assembly.

[0039] The positioning stage is a stage for positioning the element rod to the cutting position. In practice, the push assembly and the baffle are spaced apart, and the element rod is installed at the space between the two.

[0040] The pushing assembly can push the element rod toward the baffle plate by pushing the element rod, until the element rod contacts the baffle plate. Thus, the pushing assembly and the baffle plate can jointly position the element rod, thereby reducing the risk of the element rod shaking during the cutting process.

[0041] During the cutting process, the laser cutting assembly is moved to a set position to perform laser cutting on the element rod along the radial direction of the element rod, thereby cutting the element rod into small segments of element rods of specified length.

[0042] Since a laser cutting assembly is used to perform laser cutting on the element rods, when laser cutting is not in use, components such as the laser cutting head and optical fiber of the laser cutting assembly can be moved away from the fast reactor assembly, thereby greatly increasing the life of the laser cutting assembly.

[0043] The laser shearing method of the embodiment of the present application is used to cut the element rods of the fast reactor assembly, which includes the following steps: in the positioning stage, the element rod is pushed toward the side close to the baffle by the pushing assembly so that the end of the element rod close to the baffle contacts the baffle. In the cutting stage, the laser cutting assembly is controlled to cut the element rod along the radial direction of the element rod. The speed of cutting the element rod by laser is fast, the secondary pollution waste and water are small, and there is no deformation or residual stress on the cutting surface, so the shearing effect is good. In addition, laser cutting uses optical fiber transmission, which can be applied to difficult-to-reach or highly radioactive areas. At the same time, its non-contact characteristics also extend the service life of the cutting tool, thereby further improving the cutting efficiency.

[0044] In one embodiment, in the positioning stage, after the end of the element rod close to the baffle contacts the baffle, the laser cutting method further comprises the following steps:

[0045] The pressure plate assembly is controlled to move toward the side close to the component rod so that the pressure plate assembly presses the component rod to limit the movement of the component rod.

[0046] Therefore, during the positioning stage, on the one hand, the element rod is positioned by the pushing assembly and the baffle, and on the other hand, after the pushing assembly and the baffle limit the element rod, the element rod is pressed by the pressure plate assembly, which can further improve the stability of the element rod during the cutting process.

[0047] In one embodiment, after the cutting stage, the laser shearing method further comprises the following steps:

[0048] The pressure plate assembly is controlled to move toward the side away from the component rod to separate the pressure plate assembly from the component rod.

[0049] The pushing assembly is controlled to push the component rod again until it contacts the baffle plate, and the pressing plate assembly is controlled to press the component rod again.

[0050] Control the laser cutting assembly to cut the component rod again.

[0051] Specifically, in the related art, the element rod of the fast reactor assembly is wrapped with a 1-2mm thick stainless steel wire. However, the existence of this stainless steel wire will cause the element rod to curl up during the cutting and pushing process, and the wire will be lifted during the cutting process, which will also affect the cutting process to a certain extent. The requirement for cutting the element rod of the fast reactor assembly is to cut the element rod with the smallest possible cut seam, so as to maximize the fuel recovery rate, and to minimize the amount of slag on the cut surface and make the cut surface as flat as possible to maximize the smoothness of the short-segment transportation process.

[0052] The laser shearing method of this embodiment, after the pushing assembly pushes the component rod to contact the baffle, presses the component rod through the pressure plate assembly, and lifts the pressure plate assembly after the component rod is pushed into place, which can effectively solve the problem of the component rod curling up around the wire during the pushing process.

[0053] It should be noted that a single component rod needs to be cut into multiple sections. Therefore, after completing a cut, the pressure plate assembly can be lifted to facilitate pushing the component rod again, and the component rod can be pressed again by the pressure plate assembly to facilitate cutting the component rod again by the laser cutting assembly.

[0054] In one embodiment, during the cutting stage, the laser cutting head of the laser cutting assembly is spaced apart from the element rod, and the distance between the laser cutting head and the element rod is 1 cm. That is to say, by setting the laser cutting head 10 mm away from the surface of the element rod, the cutting quality can be guaranteed and the influence on the movement of the laser cutting head caused by the warping of the wire can be avoided.

[0055] In one embodiment, the fast reactor assembly includes a wire wound on an element rod, and during the cutting stage, the laser cutting assembly cuts the element rod and the wire synchronously. That is, during the cutting stage, the element rod and the wire can be cut simultaneously, which can reduce the risk of the wire curling, thereby facilitating the pushing of the element rod, so as to facilitate multiple cutting of the element rod.

[0056] Laser cutting is an extremely complex thermal processing process, involving the interaction between materials, laser beams and cutting auxiliary gases. The entire process is affected by many factors. These parameters involve material type, thickness, surface condition, laser mode, laser power, cutting speed, auxiliary gas type, gas pressure, focus position, nozzle diameter and height, etc., and the combination of these parameters also has a significant impact on the quality of laser cutting.

[0057] In one embodiment, the cutting speed of the laser cutting assembly for cutting the element rod is greater than or equal to 0.3 m / min and less than or equal to 1 m / min. For example, 0.3 m / min, 0.7 m / min or 1 m / min. It should be noted that controlling the cutting speed within the above range can better facilitate the laser cutting assembly to cut the element rod, and can achieve the purpose of efficiently cutting the element rod.

[0058] In one embodiment, the focal position of the laser cutting assembly is greater than or equal to -25 mm and less than or equal to -15 mm. For example, -25 mm, -20 mm or -15 mm. It should be noted that controlling the focal position within the above range can better facilitate the laser cutting assembly to cut off the component rod, and can achieve the purpose of efficiently cutting off the component rod.

[0059] In one embodiment, the power of the laser cutting assembly is greater than or equal to 7200 W and less than or equal to 12000 W. For example, 7200 W, 9600 W or 12000 W. It should be noted that controlling the power within the above range can better facilitate the laser cutting assembly to cut off the component rods, and can achieve the purpose of efficiently cutting off the component rods.

[0060] In one embodiment, the auxiliary gas of the laser cutting assembly is nitrogen or air. It should be noted that using nitrogen or air as the auxiliary gas can facilitate cutting.

[0061] In one embodiment, the air pressure of the laser cutting assembly is greater than or equal to 10 MPa and less than or equal to 18 MPa, such as 10 MPa, 15 MPa or 18 MPa. It should be noted that using the air pressure within the above range can facilitate cutting.

[0062] In one embodiment, the laser cutting separation method further comprises the following steps:

[0063] The process parameters of the laser cutting assembly for cutting the element rod are determined by orthogonal test; wherein the test factors of the orthogonal test include at least one of the cutting speed, focus position, power, auxiliary gas and gas pressure.

[0064] Specifically, the process parameters of the laser cutting separation method are obtained through orthogonal experiments, and different laser cutting parameters are used to cut the simulated component rods. The final cutting parameters can maintain a small cutting width while ensuring the cutting of the component rods and the winding, and the amount of slag on the cut surface is small, the roughness is low, and it will not affect the subsequent short-segment transportation.

[0065] The orthogonal test mainly examines the effects of cutting speed, focus position, power, auxiliary gas medium type and gas pressure on cutting quality. According to the actual situation, the test factors of the orthogonal test can include one of the above factors, or multiple or all of the above factors.

[0066] It should be noted that other parameters such as the ratio of cutting head lenses and optical fiber core diameter can remain unchanged. The experimental results can be obtained by visual observation, roughness meter measurement and optical microscope measurement to obtain the component rod cutting damage, wire winding cutting damage, slit width, cut surface roughness, cut surface slag amount (mm), etc. under different experimental conditions, thereby comprehensively considering factors such as cutting quality.

[0067] It can be seen that the process parameters obtained by orthogonal test can not only ensure efficient cutting of component rods, but also ensure that the slit width is small enough, the cutting surface roughness, and the amount of slag are small enough. In this way, the laser cutting time is guaranteed, the small slit width ensures less fuel damage and less debris, and the later cleaning of the hot chamber will be much easier. The roughness of the cutting surface and the amount of slag are small enough to minimize the risk of blockage caused by short sections bridging each other during transportation.

[0068] In a specific embodiment, the parameters of the orthogonal test are as follows.

[0069] Table 1. Table of fixed parameters of orthogonal test

[0070] Fixed parameters value Cutting head lens ratio 1:2 Fiber core diameter (μm) 100 Cutting height (mm) 10 Cutting nozzle diameter (mm) 3 Duty cycle (%) 50 Pulse frequency (Hz) 4000

[0071] Table 2 Experimental factors of orthogonal experiment

[0072]

[0073] Table 3 Cutting results

[0074]

[0075]

[0076] In one embodiment, the cutting speed is 0.3 m / min, the focal position is -20 mm, the power is 9600 W, the auxiliary gas is air, and the gas pressure is 15 MPa.

[0077] Specifically, according to the orthogonal test results, the cutting speed, focus position, power, auxiliary gas and gas pressure are determined to adopt the above cutting process conditions, which can ensure the cutting quality and cutting speed to the greatest extent. In addition, the existence of the winding wire does not affect the pushing of the component rod and the movement of the laser cutting head, and has a smaller slit width, cut surface roughness and dross amount.

[0078] In one embodiment, in an orthogonal test, aluminum oxide ceramics are used to replace the fuel in the element rod, thereby being able to better simulate the cutting condition of the element rod.

[0079] In one embodiment, the cutting platform further comprises a working space and a pressing plate assembly, wherein the working space is used to place the component rod, and the pressing plate assembly is movably arranged on the top side of the working space, and the pressing plate assembly can be moved to switch between pressing the component rod and separating from the component rod. Thus, the movement of the pressing plate assembly relative to the component rod can be better realized to switch between pressing and separating.

[0080] In the description of the present application, the description with reference to the terms "in one embodiment", "in some embodiments", "in a specific embodiment", or "exemplary" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the present application, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine different embodiments or examples described in the present application and the features of different embodiments or examples without contradiction.

[0081] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A laser shearing method for cutting component rods of a fast reactor assembly, characterized in that: The laser shearing method comprises a positioning stage and a cutting stage, and the laser shearing method comprises the following steps: In the positioning stage, the element rod is pushed toward the side close to the baffle by the pushing assembly, so that the end of the element rod close to the baffle contacts the baffle; During the cutting stage, the laser cutting assembly is controlled to cut the element rod along the radial direction of the element rod.

2. The laser shearing method according to claim 1, characterized in that: In the positioning stage, after the end of the element rod close to the baffle contacts the baffle, the laser cutting method further comprises: The pressure plate assembly is controlled to move toward the side close to the element rod so that the pressure plate assembly presses the element rod to limit the movement of the element rod.

3. The laser cutting method according to claim 2, characterized in that: After the cutting stage, the laser shearing method further comprises: Controlling the pressing plate assembly to move toward a side away from the element rod, so that the pressing plate assembly is separated from the element rod; Control the pushing assembly to push the element rod again until it contacts the baffle, and control the pressing plate assembly to press the element rod again; The laser cutting assembly is controlled to cut the element rod again.

4. The laser shearing method according to any one of claims 1 to 3, characterized in that: During the cutting stage, the laser cutting head of the laser cutting assembly is spaced apart from the element rod, and the distance between the laser cutting head and the element rod is 1 cm; and / or, The fast reactor assembly comprises a plurality of the element rods, and during the cutting stage, the laser cutting assembly performs synchronous cutting on each of the element rods; and / or, The fast reactor assembly includes a wire wound around the element rod. During the cutting stage, the laser cutting assembly synchronously cuts the element rod and the wire.

5. The laser shearing method according to any one of claims 1 to 3, characterized in that: The cutting speed of the laser cutting assembly for cutting the element rod is greater than or equal to 0.3 m / min and less than or equal to 1 m / min; and / or, The focal position of the laser cutting assembly is greater than or equal to -25 mm and less than or equal to -15 mm; and / or, The power of the laser cutting assembly is greater than or equal to 7200W and less than or equal to 12000W; and / or, The auxiliary gas of the laser cutting assembly is one of nitrogen and air; and / or, The air pressure of the laser cutting assembly is greater than or equal to 10 MPa and less than or equal to 18 MPa.

6. The laser cutting and separation method according to claim 5, characterized in that: The cutting speed is 0.3 m / min, the focal position is -20 mm, the power is 9600 W, the auxiliary gas is air, and the gas pressure is 15 MPa.

7. The laser cutting and separation method according to claim 5, characterized in that: The laser cutting separation method also includes the following steps: The process parameters of the laser cutting assembly for cutting the element rod are determined by orthogonal experiment; wherein the experimental factors of the orthogonal experiment include at least one of the cutting speed, the focal position, the power, the auxiliary gas and the gas pressure.

8. The laser cutting and separation method according to claim 7, characterized in that: In the orthogonal test, alumina ceramics are used to replace the fuel in the element rods.

9. A cutting platform for use in the laser shearing method according to claim 1, characterized in that: The cutting platform includes a pushing assembly, a baffle and a laser cutting assembly. The pushing assembly is used to push the element rod toward the side close to the baffle, and the laser cutting assembly is used to cut the element rod along the radial direction of the element rod.

10. The cutting platform according to claim 9, characterized in that: The cutting platform also includes a working space and a pressure plate assembly, wherein the working space is used to place the element rod, and the pressure plate assembly can be movably arranged on the top side of the working space, and the pressure plate assembly can be moved to switch between pressing the element rod and separating from the element rod.

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