System and method for processing fuel elements

Abstract

Embodiments of the present application relate to the field of reactor fuel elements, and in particular to a system and method for treating fuel elements. The fuel elements include a shell and a plurality of pellets disposed within the shell, a cooling medium, and a gas, the plurality of pellets being below a liquid level of the cooling medium. The system includes a holding device, a heating device, and a vibrating device. The holding device is configured to hold the plurality of fuel elements; the heating device is configured to heat the plurality of fuel elements so that the cooling medium of the fuel elements is in a liquid state; and the vibrating device is configured to vibrate the holding device so as to vibrate the plurality of fuel elements, thereby allowing the gas within the liquid cooling medium to escape above the liquid level of the cooling medium. The treatment system provided by embodiments of the present application allows the liquid cooling medium to be uniformly distributed within the shell, improves the heat transfer efficiency between the shell and the pellets of the fuel elements, and avoids local overheating of the fuel elements.

Description

Technical Field

[0001] Embodiments of this application relate to the field of reactor fuel elements, and more specifically to a system and method for processing fuel elements. Background Technology

[0002] The statements herein are provided merely as background information in connection with this application and do not necessarily constitute prior art.

[0003] The fuel elements of a reactor generate heat during operation. To prevent the fuel elements from overheating and causing safety hazards, a reactor coolant is installed outside the fuel elements to cool them.

[0004] Fuel elements mainly consist of a shell and pellets installed within the shell. The heat generated during operation comes from the pellets, which is then transferred to the shell and subsequently to the reactor coolant outside the shell. When the heat transfer efficiency between the pellets and the shell is low, the heat generated by the pellets cannot be transferred to the reactor coolant in a timely manner, causing the pellet temperature to rise and resulting in localized overheating. This poses a threat to the safe operation of the fuel elements. Therefore, it is necessary to take measures to improve the heat transfer efficiency between the pellets and the shell.

[0005] Currently, a cooling medium is usually added between the shell and the core to improve the heat transfer efficiency between the core and the shell. However, when a cooling medium is added, uneven distribution of the cooling medium occurs, which prevents the heat transfer efficiency between the core and the shell from being effectively improved. Summary of the Invention

[0006] A brief overview of this application is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the application. It is not intended to identify key or essential parts of the application, nor is it intended to limit its scope. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0007] In related technologies, the usual method for adding metallic sodium to the shell is to directly add liquid sodium. Because metallic sodium has a relatively high melting point, it needs to be heated to approximately 97.8°C to melt. Therefore, during the filling process, if the container wall temperature cannot reach approximately 97.8°C, the liquid sodium may solidify rapidly upon contact with the cooler wall. This phenomenon causes metallic sodium to condense at the shell inlet, forming a blockage and preventing further addition of liquid sodium. Once this occurs, additional heating of the shell is required to remelt the solidified sodium, or the shell must be replaced and the sodium filling process restarted. This process is not only time-consuming but may also increase operational risks.

[0008] In the improved method, metallic sodium is added to the housing by directly adding solid sodium. The pellet is then placed in the housing, positioned above the solid sodium component; the housing is heated to melt the solid sodium and surround the pellet. The inventors of this application discovered that during this process, some gas becomes trapped at the lower end of the housing and compresses the liquid sodium, causing it to move upwards in an unstable manner. This results in the formation of pores and gaps within the liquid sodium, leading to uneven distribution of the liquid sodium and consequently, localized overheating of the fuel element.

[0009] To address the aforementioned problems, embodiments of this application provide a system and method for processing fuel elements. The fuel element includes a housing and a plurality of spools, a cooling medium, and gas disposed within the housing, with the spools located below the surface of the cooling medium.

[0010] In a first aspect, the system for processing fuel elements provided in the embodiments of this application includes a holding device, a heating device, and a vibration device. The holding device is used to hold multiple fuel elements; the heating device is used to heat the multiple fuel elements so that the cooling medium of the fuel elements is in a liquid state; the vibration device is used to drive the holding device to vibrate, thereby driving the multiple fuel elements to vibrate so that the gas inside the liquid cooling medium can escape to the surface of the cooling medium.

[0011] The processing system provided in the embodiments of this application drives the holding device to vibrate through a vibration device, thereby causing multiple fuel elements to vibrate. This allows the gas inside the cooling medium to escape to the surface of the cooling medium, thereby enabling the liquid cooling medium to be evenly distributed within the shell. This improves the heat transfer efficiency between the shell and the fuel element and avoids local overheating of the fuel element.

[0012] Secondly, the method for processing fuel elements provided in the embodiments of this application is implemented using the system for processing fuel elements provided in the embodiments of the first aspect of this application. Attached Figure Description

[0013] Other objects and advantages of this application will become apparent from the following description of embodiments of this application with reference to the accompanying drawings, and will help to provide a comprehensive understanding of this application.

[0014] Figure 1 This is a schematic diagram of the structure of a system for processing fuel elements provided in an embodiment of this application.

[0015] Figure 2 yes Figure 1 The diagram shows the main structure of the system that processes fuel elements.

[0016] Figure 3It is fuel element and Figure 1 The diagram shows the assembled structure of the holding device of the system that processes fuel elements.

[0017] Figure 4 yes Figure 3 The front view of the structure shown.

[0018] Figure 5 yes Figure 4 The diagram shows a cross-sectional view of the structure.

[0019] Figure 6 yes Figure 5 A magnified view of a portion of the image.

[0020] Figure 7 yes Figure 2 The diagram shown is an exploded view of the structure.

[0021] Explanation of reference numerals in the attached figures:

[0022] 100. A system for processing fuel elements;

[0023] 10. Holding device; 11. Holding part; 111. Holding member; 1111. Clamping groove; 112. Clamping member; 12. Connecting part; 13. Extension part; 14. Support part;

[0024] 20. Heating device; 21. Heating shell; 211. Half shell; 2111. Shell; 2112. Insulation component; 22. Inner shell; 221. Connecting component; 23. Gas passage; 201. Heating chamber; 2101. Opening;

[0025] 30. Vibration device; 31. Mechanical vibration part; 311. Body; 312. Vibration part; 32. Ultrasonic vibration part; 321. Mounting connector;

[0026] 40. Mounting plate; 50. Lifting device;

[0027] 60. Sealing device; 61. Bellows; 611. Sealing connector; 612. Vibration connector; 62. Sealing connection; 621. First connector; 622. Second connector; 623. Connecting fitting; 624. Mounting interface; 6241. Mating connector;

[0028] 70. Cooling device; 71. Cooling fan; 80. Control device;

[0029] 101. Guide component; 102. Guide connector; 103. Intake pipe; 104. Exit pipe;

[0030] 200. Fuel element.

[0031] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding. Detailed Implementation

[0032] Exemplary embodiments of this application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the development of any such actual embodiment to achieve the developer's specific goals, such as complying with constraints related to the system and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the content of this application.

[0033] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the equipment structure and / or processing steps closely related to the solution according to this application are shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0034] See Figure 1 and Figure 2 The system 100 (hereinafter referred to as the processing system 100) for processing fuel elements 200 provided in the embodiments of this application may include a holding device 10, a heating device 20, and a vibration device 30. The holding device 10 is used to hold a plurality of fuel elements 200; the heating device 20 is used to heat the plurality of fuel elements 200 so that the cooling medium of the fuel elements 200 is in a liquid state; the vibration device 30 is used to drive the holding device 10 to vibrate, thereby driving the plurality of fuel elements 200 to vibrate so that the gas inside the liquid cooling medium can escape to the surface of the cooling medium.

[0035] The processing system 100 provided in the embodiments of this application drives the holding device 10 to vibrate through the vibration device 30, thereby driving multiple fuel elements 200 to vibrate, so that the gas inside the cooling medium can escape to the surface of the cooling medium, thereby enabling the liquid cooling medium to be evenly distributed in the shell, which can improve the heat transfer efficiency between the shell and the fuel element and avoid local overheating of the fuel element 200.

[0036] In some embodiments, the cooling medium may be metallic sodium.

[0037] In some embodiments, the heating device 20 can heat the fuel element 200 to 550°C to process the fuel element 200.

[0038] In some embodiments, the holding device 10 can hold 10 to 30, for example, 20 fuel elements 200.

[0039] See Figure 2 In some embodiments, the vibration device 30 may include a mechanical vibration section 31, which is used to drive the holding device 10 to vibrate. Gas inside the liquid cooling medium will form bubbles inside the cooling medium. In such embodiments, the mechanical vibration section 31 can cause large bubbles inside the cooling medium to form small bubbles under mechanical vibration, which is beneficial for the bubbles to escape to the surface of the cooling medium.

[0040] Mechanical vibration unit 31 is, for example, a mechanical vibration table.

[0041] In some embodiments, the mechanical vibration unit 31 can provide vertical thrust, enabling the fuel element 200 to vibrate in the vertical direction. In some embodiments, the maximum thrust that the mechanical vibration unit 31 can provide is 10 kN.

[0042] See Figure 2 In some embodiments, the mechanical vibration part 31 may include a body 311 and a vibration part 312 capable of vibrating relative to the body 311. See also Figure 3 and Figure 4 In some embodiments, the holding device 10 may include a holding portion 11 and a connecting portion 12 connected to the holding portion 11. The holding portion 11 is used to hold a plurality of fuel elements 200, and the connecting portion 12 is used to connect to a vibrating portion 312 so that the vibrating portion 312 drives the connecting portion 12 and the holding portion 11 to vibrate. In such embodiments, the vibration of the fuel elements 200 can be achieved by driving the connecting portion 12 and the holding portion 11 to vibrate through the vibrating portion 312.

[0043] See Figure 3 and Figure 4 In some embodiments, the holding device 10 may further include an extension 13 connected to the connecting portion 12. In some embodiments, the holding portion 11 may include multiple layers of holding members 111 and multiple clamping members 112, with the multiple layers of holding members 111 connected to the extension 13, and each fuel element 200 connected to each layer of holding members 111 via a clamping member 112. Since the fuel element 200 is relatively long (the fuel element 200 can reach 1 meter), in such embodiments, holding the fuel element 200 by the multiple layers of holding members 111 and multiple clamping members 112 can ensure the stability of the fuel element 200 during vibration and prevent the fuel element 200 from shaking.

[0044] See Figure 3In some embodiments, a clamping groove 1111 may be formed on the radially outer side of the retainer 111, and each fuel element 200 is clamped in the clamping groove 1111 by the clamping member 112. In such embodiments, clamping the fuel element 200 by the clamping member 112 and the clamping groove 1111 can prevent the fuel element 200 from separating from the retainer 111 during vibration.

[0045] In some embodiments, the clamping element 112 is, for example, a clamp.

[0046] In some embodiments, the retainer 111 is, for example, an annular plate.

[0047] join Figure 4 and Figure 5 In some embodiments, the holding device 10 may further include a support portion 14 connected to the connecting portion 12. The support portion 14 is disposed below the multi-layer holding member 111, and multiple fuel elements 200 contact the support portion 14 so that the support portion 14 supports the multiple fuel elements 200. In such embodiments, supporting the multiple fuel elements 200 by the support portion 14 helps to improve the stability of the holding portion 11 in holding the fuel elements 200.

[0048] See Figure 5 In some embodiments, the heating device 20 is configured to form a heating cavity 201 with an opening at the bottom. Figure 1 and Figure 3 In some embodiments, the processing system 100 may further include a mounting plate 40, a lifting device 50, a sealing device 60, and a gas supply component. The mounting plate 40 is disposed on the body 311 and forms a through hole through which the connecting portion 12 of the retaining device 10 is connected to the vibrating portion of the mechanical vibrating portion 31. The lifting device 50 is disposed on the mounting plate 40 and is used to lift and lower the heating device 20 so that the retaining portion 11 is located outside or inside the heating chamber 201. The sealing device 60 is used to seal the heating chamber 201 when the lifting device 50 lowers the heating device 20 to abut against the sealing device 60. The gas supply component provides protective gas to the heating chamber 201. In such embodiments, the lifting device 50 lifts and lowers the heating device 20 to load and unload the retaining device 10 and the fuel element 200; the sealing device 60 seals the heating chamber 201; and the gas supply component provides protective gas to the heating chamber 201, preventing external air from entering the heating chamber 201 and preventing the fuel element 200 from contacting external air in the event of damage.

[0049] See Figure 3In some embodiments, the retainer 111, support 14, extension 13, and connecting part 12 can be configured as a hollow structure. The hollow structure reduces the overall weight; furthermore, since the cooling medium inside the housing of the fuel element 200 expands when heated, it may cause the housing to break and leak out. In such embodiments, configuring the retainer 111, support 14, extension 13, and connecting part 12 as a hollow structure allows the cooling medium leaking out of the housing to flow below the retainer 10, preventing it from splashing everywhere under vibration, thus facilitating the collection of the leaked cooling medium and also ensuring uniform distribution of the protective gas.

[0050] See Figure 6 In some embodiments, the sealing device 60 may include a bellows 61 and a sealing connection 62 connected to the bellows 61. The bellows 61 connects the vibrating part 312 and the mounting plate 40; the sealing connection 62 is disposed on the mounting plate 40 and is used to seal the heating device 20 when the lifting device 50 lowers the heating device 20 so that the retaining part 11 is located inside the heating chamber 201. In such an embodiment, since the bellows 61 connects the vibrating part 312 and the mounting plate 40, and the sealing connection 62 is disposed on the mounting plate 40 and connected to the bellows 61, the bellows 61, the sealing connection 62, and the vibrating part 312 can jointly seal the heating chamber 201. Meanwhile, since the vibrating part 312 is connected to the mounting plate 40 through the bellows 61, the mounting plate 40 will not vibrate with the vibrating part 312 when the vibrating part 312 vibrates; since the lifting device 50 and the sealing connection part 62 are both provided on the mounting plate 40, the heating device 20 will not vibrate with the vibrating part 312 when the vibrating part 312 vibrates.

[0051] See Figure 5 In some embodiments, the heating device 20 may further include a heating outer shell 21 and an inner shell 22, with the inner shell 22 disposed radially inside the heating outer shell 21 and configured to form a heating cavity 201. An opening 2101 is formed at the bottom of the heating outer shell 21, and the lower end of the inner shell 22 extends from the opening 2101 to a position protruding from the heating outer shell 21. The heating outer shell 21 can heat the inner shell 22, thereby heating the holding portion 11 and the fuel element 200.

[0052] The heating outer shell 21 is, for example, a heating furnace, and the inner shell 22 is, for example, a high-temperature vessel. In some embodiments, the heating device 20 may further include a heating connector for connecting the heating outer shell 21 and the inner shell 22. The heating connector may be, for example, a screw.

[0053] See Figure 5In some embodiments, the heating housing 21 may include two half-shells 211, each half-shell 211 having lateral openings, the lateral openings of the two half-shells 211 being arranged opposite to each other; the two half-shells 211 are hinged together so that the relative position of the two half-shells 211 can be switched between an open state and a closed state; wherein, when the relative position of the two half-shells 211 is in the open state, the inner housing 22 is exposed. In some embodiments, the two half-shells 211 may also have bottom openings communicating with the lateral openings, the bottom openings of the two half-shells 211 together forming an opening 2101.

[0054] See Figure 5 In some embodiments, each half-shell 211 may include a shell 2111, a heating element, and an insulation element 2112. The heating element is disposed on the insulation element 2112 for heating the inner shell 22; the insulation element 2112 is connected to the shell 2111 for insulating the heating element; the shell 2111 is disposed outside the insulation element 2112 for protecting the heating element and the insulation element 2112. In some embodiments, the shell 2111 and the insulation element 2112 are configured to form a side opening and a bottom opening.

[0055] The inner shell 22 is a cylindrical component with a closed upper end and an open lower end. The sealing device 60 is used to seal the inner shell 22.

[0056] See Figure 6 In some embodiments, the sealing connection 62 may be fixedly connected to the bellows 61. In some embodiments, the sealing connection 62 may include a first connector 621, a second connector 622, and a connecting pipe 623. The first connector 621 is sealed to the inner shell 22, the second connector 622 is fixedly connected to the bellows 61, and the connecting pipe 623 is used to connect the first connector 621 and the second connector 622.

[0057] See Figure 6 In some embodiments, a connector 221 may be formed at the lower end of the inner shell 22. The connector 221 is sealed to the first connector 621 so that the bellows 61, the sealing connection 62, and the vibration part 312 can jointly seal the heating chamber 201.

[0058] See Figure 6 In some embodiments, the sealing device 60 may include a sealing connector 611 and a vibration connector 612. The sealing connector 611 and the vibration connector 612 are respectively connected to both ends of the bellows 61. The sealing connector 611 is fixedly connected to the second connector 622 of the sealing connection part 62, and the sealing connector 611 is also connected to the mounting plate 40; the vibration connector 612 is connected to the vibration part 312.

[0059] The first connector 621, the second connector 622, the sealing connector 611, and the vibration connector 612 are, for example, flanges.

[0060] In some embodiments, the protective gas can be an inert gas, such as argon, and correspondingly, the gas supply can be an inert gas cylinder, such as an argon cylinder.

[0061] See Figure 5 In some embodiments, the processing system 100 may further include an air intake pipe 103, which is disposed at the lower end of the inner shell 22 and located outside the heating outer shell 21. The air intake pipe 103 is in fluid communication with the heating chamber 201 and the gas supply component. The protective gas provided by the gas supply component can enter the heating chamber 201 through the air intake pipe 103.

[0062] See Figure 5 In some embodiments, the processing system 100 may further include an exhaust pipe 104, which is disposed at the upper end of the inner shell 22 and is in fluid communication with the heating chamber 201. Gas in the heating chamber 201 can flow out of the heating chamber 201 through the exhaust pipe 104. In some embodiments, the heating outer shell 21 has a gas channel 23, which is formed at the upper end of the heating outer shell 21. The exhaust pipe 104 is disposed in the gas channel 23 and extends from the gas channel 23 to the outside of the heating outer shell 21.

[0063] join Figure 2 In some embodiments, the processing system 100 may further include a guide member 101 and a guide connector 102. The guide member 101 is disposed on the mounting plate 40, and the guide member 101 and the heating housing 21 are connected via the guide connector 102, for providing guidance to the heating device 20 when the lifting device 50 drives the heating device 20 to rise and fall. In some embodiments, the guide member 101 may be disposed between the lifting device 50 and the heating device 20. The guide member 101 is, for example, a rod. The lifting device 50 is, for example, an electric push cylinder.

[0064] See Figure 2 In some embodiments, the vibration device 30 may further include an ultrasonic vibration unit 32, which is used to drive the holding device 10 to vibrate via ultrasound. In such embodiments, after the mechanical vibration unit 31 drives the fuel element 200 to mechanically vibrate, causing large bubbles in the cooling medium to form small bubbles under the action of mechanical vibration, the holding device 10 is then driven to vibrate via ultrasound, so that the small bubbles in the cooling medium can move upward to above the liquid surface of the cooling medium. The embodiments of this application, through the synergistic action of the mechanical vibration unit 31 and the ultrasonic vibration unit 32, facilitate the escape of gas inside the liquid cooling medium to above the liquid surface of the cooling medium. The ultrasonic vibration unit 32 is, for example, an ultrasonic vibration generator.

[0065] In some embodiments, the ultrasonic vibration unit 32 is capable of causing the fuel element 200 to vibrate at an ultrasonic vibration frequency of 20 kHz. In some embodiments, the number of ultrasonic vibration units 32 may be one or more, for example, two. See also Figure 6 In some embodiments, the sealing connection 62 may further include at least one mounting interface 624 for mounting the ultrasonic vibration part 32. The mounting interface 624 is disposed on the connecting pipe 623 and communicates with the connecting pipe 623. The ultrasonic vibration part 32 can pass through the mounting interface 624 and abut against the extension 13 of the retaining device 10, thereby transmitting ultrasound to the extension 13 of the retaining device 10.

[0066] See Figure 6 and Figure 7 In some embodiments, the ultrasonic vibration part 32 is provided with a mounting connector 321, and the end of the mounting interface 624 facing the ultrasonic vibration part 32 is provided with a mating connector 6241. The mounting connector 321 can be connected with the mating connector 6241 so that the ultrasonic vibration part 32 can be mounted to the mounting interface 624.

[0067] See Figure 1 In some embodiments, the processing system 100 may further include a cooling device 70 for cooling components within the processing system 100. In some embodiments, the cooling device 70 may include a cooling fan 71, which can provide cooling to other components in the processing system 100 to prevent damage due to excessive temperature, thereby protecting other components in the processing system 100. For example, the cooling fan 71 can provide cooling to the mechanically vibrating part 31 to protect it.

[0068] See Figure 1 In some embodiments, the processing system 100 may further include a control device 80 for controlling and recording the temperature inside the heating chamber 201, as well as the vibration thrust, vibration frequency, vibration displacement, etc. of the mechanical vibration unit 31. In some embodiments, the processing system 100 may further include a power regulator, and the control device 80 controls the temperature inside the heating chamber 201 by adjusting the power regulator.

[0069] Embodiments of this application also provide a method for processing a fuel element 200 (hereinafter referred to as the processing method). The processing method is implemented using the processing system 100 provided in any embodiment of this application.

[0070] In some embodiments, the processing method may include: heating the fuel element 200 to make the cooling medium of the fuel element 200 liquid; driving the fuel element 200 to mechanically vibrate so that large bubbles in the cooling medium form small bubbles under the action of mechanical vibration; and then using ultrasound to vibrate the fuel element 200 so that the small bubbles in the cooling medium can move upward to above the liquid surface of the cooling medium.

[0071] In the embodiments of this application, mechanical vibration in the vertical direction is first performed (the direction of mechanical vibration is the same as the axis of the fuel element 200). Because the fuel element 200 has a stroke during the vertical vibration, most bubbles that are not obstructed in the vertical direction (i.e., bubbles not located between two core blocks can move directly upwards to the surface of the cooling medium without obstruction) can be eliminated. Bubbles stuck between two adjacent core blocks can be moved horizontally to the outside of the core blocks and further upwards to the surface of the cooling medium. Furthermore, large bubbles can be vibrated into smaller bubbles. Then, ultrasonic vibration is used; since ultrasound typically has a low amplitude at high frequencies, it can cause the small bubbles to move upwards. The embodiments of this application, through the synergistic effect of mechanical vibration and ultrasonic waves, facilitate the escape of gas from inside the liquid cooling medium to the surface of the cooling medium.

[0072] In some embodiments, before heating the fuel element 200, the air in the heating chamber 201 may be replaced with a protective gas to protect the fuel element 200.

[0073] Specifically, the air in the heating chamber 201 can be replaced with protective gas through the intake pipe 103, the exhaust pipe 104, and the gas supply component to protect the fuel element 200.

[0074] In some embodiments, before heating the fuel element 200, the size and distribution of gas bubbles formed inside the liquid cooling medium can be determined by ultrasound. Based on the size and distribution of the gas bubbles inside the liquid cooling medium, it can be determined whether to use ultrasonic vibration or mechanical vibration first followed by ultrasonic vibration. In such embodiments, it is possible to more rationally and quickly allow the gas inside the liquid cooling medium to escape to the surface of the cooling medium.

[0075] In some embodiments, when the bubble size inside the liquid cooling medium is larger than a preset size, mechanical vibration is used first, followed by ultrasonic vibration; when the bubble size inside the liquid cooling medium is smaller than the preset size, ultrasonic vibration can be used directly. In some embodiments, the preset size can be 1.5 mm.

[0076] The inventors of this application discovered that when a bubble is located between two adjacent core blocks, even if the bubble size is smaller than a preset size, it is difficult to move the bubble out from between the two core blocks using ultrasonic vibration. Therefore, in some embodiments, when the bubble size inside the liquid cooling medium is smaller than the preset size, but some bubbles are located between two adjacent core blocks, mechanical vibration is first used to move the bubbles stuck between the two adjacent core blocks horizontally to the outside of the core blocks, and further upward to above the surface of the cooling medium; then ultrasonic vibration is used.

[0077] It's easy to understand that for fuel elements, the casing is welded together from a sheath tube and end caps at both ends. Using mechanical vibration to remove air bubbles carries the risk of adversely affecting the weld seams.

[0078] Therefore, in the embodiments of this application, it is first determined whether mechanical vibration is needed based on the size and position of the bubble. When the bubble is small and there is no obstruction in the vertical direction, ultrasonic vibration can be used to remove the bubble, so as to minimize the risk of adverse effects on the weld.

[0079] When bubbles are large or exist between two core blocks, mechanical vibration is used to remove them.

[0080] In some embodiments, when no bubbles are located between two adjacent core blocks, mechanical vibration can easily cause the bubbles to rise to the liquid surface. Therefore, small-amplitude mechanical vibration can be used to reduce the risk of adverse effects on the weld. When some bubbles are located between two adjacent core blocks, the amplitude of the mechanical vibration used is greater than that used when no bubbles are located between two adjacent core blocks, in order to facilitate the removal of bubbles from the gap between the two core blocks.

[0081] In some embodiments, when some bubbles are located between two adjacent core blocks, the amplitude of the mechanical vibration used can be 5-10 mm; when no bubbles are located between two adjacent core blocks, the amplitude of the mechanical vibration used can be less than 5 mm.

[0082] In some embodiments, since the processing system of this application can process multiple fuel elements simultaneously, the multiple fuel elements to be processed can be grouped according to the size and distribution of the gas bubbles formed by the fuel elements. Fuel elements requiring larger amplitude mechanical vibration are grouped into one group, fuel elements requiring smaller amplitude mechanical vibration are grouped into another group, and fuel elements requiring only ultrasonic vibration are grouped into a third group. The fuel elements from different groups are then placed into the processing system in batches for processing. This minimizes the adverse effects of vibration on the fuel elements when unnecessary.

[0083] The following describes in detail, with reference to the accompanying drawings and specific embodiments, a method for processing a fuel element 200 according to an embodiment of this application.

[0084] Multiple fuel elements 200 are assembled with the holding device 10, and the connecting part 12 is connected with the vibration part 312. The high-temperature vessel 22 is lowered by the electric push cylinder 50, so that the fuel elements 200 enter the heating chamber 201. The two half shells 211 of the heating furnace 21 are set to the closed state, so that the heating furnace 21 can cover the high-temperature vessel 22.

[0085] When the argon cylinder is opened, argon gas enters the heating chamber 201 through the inlet pipe 103. The air in the heating chamber 201 flows out of the heating chamber 201 through the outlet pipe 104. During this process, the gas pressure in the heating chamber 201 is maintained at 0.05 MPa, and pressure protection is provided by a pressure relief valve with a pressure setting of 0.1 MPa. When the gas pressure in the heating chamber 201 exceeds 0.05 MPa, the heating chamber 201 can automatically depressurize.

[0086] The heating element of the heating shell 21 is activated, causing the temperature inside the heating chamber 201 to slowly rise to 550°C.

[0087] Start the cooling fan 81 to provide cooling for the mechanical vibration table 31, so that the temperature of the mechanical vibration table 31 does not get too high.

[0088] The target temperature of the heating chamber 201 is set by the control system, and the heating element is adjusted to stabilize the temperature inside the heating chamber 201 at the target temperature. Since the argon gas inside the heating chamber 201 expands in volume after being heated, the gas outlet pipe 104 needs to be kept open at all times during this process so that the high-temperature argon gas inside the heating chamber 201 can leave the heating chamber 201 and maintain the gas pressure inside the heating chamber 201 within the required range.

[0089] The mechanical vibration table 31 and the ultrasonic vibration generator 32 are started sequentially by setting the vibration thrust, vibration frequency, amplitude and vibration time of the mechanical vibration table 31, as well as the vibration frequency and vibration time of the ultrasonic vibration generator 32 by setting the vibration thrust, vibration frequency, vibration time of the mechanical vibration table 31 and the ultrasonic vibration generator 32 by setting the vibration thrust, vibration frequency, vibration frequency and vibration time of the ultrasonic vibration generator 32 by setting the vibration time and vibration time of the ultrasonic vibration generator 31.

[0090] After the vibration ends, heating is stopped, and the temperature of the heating chamber 201 is allowed to drop slowly. At the same time, argon gas is introduced into the heating chamber 201 to maintain the pressure inside the heating chamber 201 at 0.05 MPa, so as to prevent the argon gas inside the heating chamber 201 from cooling and forming a vacuum.

[0091] The heating device 20 is lifted by the electric push cylinder 50, so that the fuel element 200 leaves the heating chamber 201 and is removed from the holding device 10, thus completing the processing of the fuel element 200.

[0092] Regarding the embodiments of this application, it should also be noted that, without conflict, the embodiments of this application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0093] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A system for processing a fuel element, the fuel element comprising a housing and a plurality of cores disposed within the housing, a cooling medium, and a gas, the plurality of cores being located below the liquid level of the cooling medium; characterized in that, The system includes: A holding device for holding multiple fuel elements; A heating device is used to heat the plurality of fuel elements so that the cooling medium of the fuel elements is in a liquid state; A vibration device is used to drive the holding device to vibrate, thereby driving the multiple fuel elements to vibrate, so that the gas inside the liquid cooling medium can escape to the surface of the cooling medium. The vibration device includes a mechanical vibration part, which is used to drive the holding device to vibrate. The mechanical vibrating part includes a body and a vibrating part capable of vibrating relative to the body; The holding device includes a holding part and a connecting part connected to the holding part. The holding part is used to hold the plurality of fuel elements, and the connecting part is used to connect to the vibrating part so that the vibrating part drives the connecting part and the holding part to vibrate. The heating device is configured to form a heating cavity with an opening at the bottom; The system also includes: A mounting plate is disposed on the body, and the mounting plate forms a through hole. The connecting part of the retaining device is connected to the vibration part of the mechanical vibration part through the through hole. A lifting device, disposed on the mounting plate, is used to drive the heating device to rise or fall, so that the holding part is located outside or inside the heating cavity; A sealing device is used to seal the heating chamber when the lifting device lowers the heating device to abut against the sealing device. A gas supply component is used to supply protective gas to the heating chamber.

2. The system according to claim 1, characterized in that, The retaining device further includes an extension portion connected to the connecting portion; The retaining portion includes multiple retaining members and multiple clamping members. The multiple retaining members are connected to the extension portion, and each fuel element is connected to each layer of the retaining members via a clamping member.

3. The system according to claim 2, characterized in that, The retainer forms a clamping groove on its radially outer side, and each fuel element is clamped in the clamping groove by the clamping member.

4. The system according to claim 2, characterized in that, The retaining device further includes a support portion connected to the connecting portion. The support portion is disposed below the multi-layer retaining member. The plurality of fuel elements are in contact with the support portion so that the support portion supports the plurality of fuel elements.

5. The system according to claim 4, characterized in that, The retaining member, the supporting part, the extension part, and the connecting part are configured with a hollow structure.

6. The system according to claim 1, characterized in that, The sealing device includes: A bellows is used to connect the vibrating part and the mounting plate; A sealing connection is provided on the mounting plate and is connected to the bellows. The sealing connection is used to seal the connection with the heating device when the lifting device lowers the heating device so that the holding part is located inside the heating chamber.

7. The system according to claim 1, characterized in that, The vibration device further includes an ultrasonic vibration unit, which is used to drive the holding device to vibrate via ultrasound.

8. A method for processing fuel elements, said method being implemented using the system of any one of claims 1-7.

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