Settling equipment for metal fuel rods

Abstract

This invention relates to the field of nuclear reactor settling equipment technology, specifically to a settling device for metal fuel rods. The settling device includes: a base; a fuel rod support frame detachably supported on the base, the fuel rod support frame having multiple receiving slots that match the ends of the metal fuel rods so that the bottom ends of the metal fuel rods can be inserted into the receiving slots, allowing the metal fuel rods to be vertically supported on the fuel rod support frame; and multiple induction heating coils disposed within the receiving slots, used to heat the bottom ends of the metal fuel rods, causing sodium wire to melt from the bottom to form liquid sodium, thereby causing the fuel core to gradually settle within the tube shell. The settling device in this embodiment of the invention can prevent the fuel core in long metal fuel rods from damaging the inner wall of the tube shell during the settling process, and can also simultaneously perform settling treatment on multiple metal fuel rods, improving work efficiency.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of nuclear reactor settling equipment technology, specifically to a settling device for metal fuel rods. Background Technology

[0002] The statements herein are provided merely as background information relating to the invention and do not necessarily constitute prior art. Sodium-cooled fast reactors are fast breeder reactors that use liquid sodium as a coolant. Metal fuel rods are widely used in sodium-cooled fast reactors due to their high burnup and high safety characteristics. Currently, most metal fuel rods used in sodium-cooled fast reactors have a long structure to ensure that the gas generated by the fission of the fuel core in the metal fuel rod is released into the gas chamber, thus preventing the metal fuel rod shell from rupturing. Summary of the Invention

[0003] An embodiment of the present invention provides a settling device for metal fuel rods, used for settling metal fuel rods, wherein the metal fuel rod includes: a shell, a fuel core and a sodium wire, the fuel core and the sodium wire are disposed inside the shell, and the fuel core is located above the sodium wire.

[0004] The metal fuel rod settling device provided in the embodiments of the present invention includes: a base; a fuel rod support frame detachably supported on the base, the fuel rod support frame having multiple receiving grooves that match the ends of the metal fuel rods so that the bottom ends of the metal fuel rods can be inserted into the receiving grooves, and the metal fuel rods are vertically supported on the fuel rod support frame; and multiple induction heating coils disposed in the receiving grooves, the induction heating coils being used to heat the bottom ends of the metal fuel rods, causing sodium wires to melt from the bottom to form liquid sodium, so that the fuel core gradually settles in the tube shell.

[0005] The settling device in this embodiment of the invention heats the bottom of the metal fuel rod by placing an induction heating coil in the receiving groove of the fuel rod support frame. This melts the sodium wire in the metal fuel rod from the bottom up, thereby achieving the settling of the fuel core within the tube shell. This prevents the fuel core in long metal fuel rods from damaging the inner wall of the tube shell during the settling process. Furthermore, by setting multiple receiving grooves and multiple induction heating coils, multiple metal fuel rods can be settling simultaneously, improving work efficiency. Attached Figure Description

[0006] Other objects and advantages of the invention will become apparent from the following description of embodiments of the invention with reference to the accompanying drawings, and will help to provide a comprehensive understanding of the invention.

[0007] Figure 1 This is a schematic diagram of the structure of a metal fuel rod according to an embodiment of the present invention.

[0008] Figure 2 This is a schematic diagram of a settling device according to an embodiment of the present invention.

[0009] Figure 3 This is a schematic diagram of the structure of a fuel rod support frame according to an embodiment of the present invention.

[0010] Figure 4 This is a schematic diagram of the structure of a base according to an embodiment of the present invention.

[0011] Figure 5 This is a cross-sectional schematic diagram of a heating device according to an embodiment of the present invention.

[0012] Figure 6 This is a schematic diagram of the structure of a detection device according to an embodiment of the present invention.

[0013] Explanation of reference numerals in the attached figures:

[0014] 10. Base; 11. Electrical connection connector; 12. Support base; 13. Rotating base plate.

[0015] 20. Fuel rod support frame; 21. Base plate; 211. Receiving trough; 22. Support rod; 23. Support plate; 231. Groove; 24. Lifting component.

[0016] 30. Induction heating coil; 40. Heating device; 41. Heating chamber; 411. Through hole; 42. Housing; 43. Heating wire; 44. Heat exchange tube; 45. Heating wire interface; 46. Heat exchange tube interface.

[0017] 50. Detection device; 51. Moving mechanism; 52. X-ray source; 53. Imaging plate; 54. Transmission connector; 55. Power connector.

[0018] 60. Metal fuel rod; 61. Tube shell; 62. Fuel core; 63. Sodium wire; 64. End plug.

[0019] 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

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only one embodiment of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the described embodiments of this application without creative effort are within the scope of protection of this application.

[0021] It should be noted that, unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person with ordinary skill in the art to which this application pertains. Where the terms "first," "second," etc., are used throughout the text, they are used only to distinguish similar objects and should not be construed as indicating or implying their relative importance, order of precedence, or implicitly specifying the number of technical features indicated. It should be understood that the data described by "first," "second," etc., can be interchanged where appropriate. Where "and / or" appears throughout the text, it means including three parallel solutions. Taking "A and / or B" as an example, it includes solution A, or solution B, or a solution that satisfies both A and B. Furthermore, for ease of description, spatial relative terms such as "above," "below," "top," "bottom," etc., may be used here, only to describe the spatial positional relationship between one device or feature as shown in the figure and other devices or features. It should be understood that this also includes different orientations in use or operation besides those shown in the figure.

[0022] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the device structure and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0023] The inventors of this invention have discovered that, compared to traditional short-sized metal fuel rods, the long-sized metal fuel rods widely used in sodium-cooled fast reactors have a problem during the settling process: the fuel core in the metal fuel rod scratches the inner wall of the casing, easily leading to casing damage and affecting the safety of the settling process. Based on this, embodiments of this invention provide a metal fuel rod settling device to at least partially solve the above-mentioned problems.

[0024] like Figure 1 As shown, the metal fuel rod 60 in the embodiment of the present invention includes: a shell 61, a fuel core 62 and a sodium wire 63, wherein the fuel core 62 and the sodium wire are disposed inside the shell 61, and the fuel core 62 is located above the sodium wire 63.

[0025] In some embodiments, the metal fuel rod 60 further includes an end plug 64, which is sealed to the upper and lower ends of the metal fuel rod 60, and the end plug 64 at the lower end of the metal fuel rod 60 is configured to conduct heat. For example, the end plugs 64 disposed at the upper and lower ends of the metal fuel rod 60 can be connected by welding.

[0026] The sedimentation device for metal fuel rods provided in the embodiments of the present invention is used to perform sedimentation treatment on the metal fuel rods 60 of the above embodiments. Please refer to [link to relevant documentation]. Figure 2 and Figure 3The settling device includes a base 10, a fuel rod support frame 20, and multiple induction heating coils 30. The fuel rod support frame 20 is detachably supported on the base 10 and has multiple receiving slots 211 that match the ends of metal fuel rods 60, allowing the bottom ends of the metal fuel rods 60 to be inserted into the receiving slots 211, thus vertically supporting the metal fuel rods 60 on the fuel rod support frame 20. Multiple induction heating coils 30 are disposed within the receiving slots 211 and are used to heat the bottom ends of the metal fuel rods 60, causing the sodium wire 63 to melt from the bottom up to form liquid sodium, thereby causing the fuel core 62 to gradually settle within the casing 61.

[0027] In the metal fuel rod settling device of this embodiment, by placing the induction heating coil 30 in the receiving groove 211 of the fuel rod support frame 20, the bottom end of the metal fuel rod 60 is heated, thereby melting the sodium wire 63 in the metal fuel rod 60 from the bottom. This causes the fuel core 62 to gradually settle during the melting of the sodium wire 63, thus achieving the settling of the fuel core 62 within the tube shell 61. This prevents the fuel core 62 in long metal fuel rods from damaging the inner wall of the tube shell 61 during the settling process. Furthermore, by providing multiple receiving grooves 211 and multiple induction heating coils 30, multiple metal fuel rods 60 can be settling simultaneously, improving work efficiency.

[0028] like Figure 4 As shown, in some embodiments, the top of the base 10 is provided with an electrical connection connector 11, which is used to connect to an external power source to energize the base 10. The bottom of the fuel rod support frame 20 is provided with an electrical connection interface, which is connected to each induction heating coil 30, and the electrical connection interface matches the electrical connection connector 11. When the fuel rod support frame 20 is supported on the base 10, the electrical connection connector 11 connects to the electrical connection interface to supply power to each induction heating coil 30, thereby enabling each induction heating coil 30 to heat the bottom end of the metal fuel rod 60.

[0029] For example, the electrical connection connector 11 at the top of the base 10 can be a quick-connect connector, and the electrical connection interface at the bottom of the fuel rod support frame 20 can be a quick-connect interface. The fuel rod support frame 20 and the base 10 are connected by quick-connect connector and quick-connect interface to enable the fuel rod support frame 20 to be supported on the base 10, while providing power to each induction heating coil 30.

[0030] In this embodiment, the electrical connection connector 11 can be circular; for example, it can be... Figure 4The fuel rod support frame 20 is shown as a cone shape, and the electrical connection interface is also set as a circle, matching the electrical connection connector 11. When the fuel rod support frame 20 is supported on the base 10, there is no need to position the fuel rod support frame 20. The fuel rod support frame 20 can be connected to the base 10 at any angle, thereby realizing a quick-connect connection.

[0031] like Figure 3 As shown, in some embodiments, the fuel rod support frame 20 may include: a base plate 21, a support rod 22, and at least one support plate 23. The top surface of the base plate 21 has a plurality of receiving grooves 211 for receiving the ends of the metal fuel rods 60. The bottom of the base plate 21 is provided with an electrical connection interface for mating with the electrical connection connector 11 on the top of the base 10. The support rod 22 is vertically disposed on the base plate 21, and the metal fuel rods 60 are inserted into the receiving grooves 211 parallel to the support rod 22. At least one support plate 23 is spaced apart at different heights from the support rod 22. The edges of the support plates 23 have a plurality of grooves 231 corresponding to the plurality of receiving grooves 211. The grooves 231 are used to receive the metal fuel rods, thereby fixing the metal fuel rods 60 to the fuel rod support frame 20 through the plurality of grooves 231 and the plurality of receiving grooves 211, keeping the metal fuel rods 60 in a vertical position and achieving a limiting effect on the metal fuel rods 60.

[0032] In this embodiment, two support plates 23 are provided, spaced apart at different heights of the support rod 22 and parallel to the base plate 21. Multiple grooves 231 on the edges of the two support plates 23 are correspondingly arranged so that the metal fuel rod 60 can pass sequentially through the grooves 231 of the two support plates 23 and be inserted into the receiving groove 211, thereby fixing the metal fuel rod 60 to the fuel rod support frame 20 and enhancing the stability of the metal fuel rod. For example, the two support plates 23 are respectively located in the middle and near the top of the fuel rod support frame 20 to improve the fixing effect of the metal fuel rod.

[0033] like Figure 3 As shown, in some embodiments, the fuel rod support frame 20 may further include a lifting member 24, which is disposed at the upper end of the support rod 22 and is used to connect with external lifting equipment to lift and disassemble the fuel rod support frame 20.

[0034] like Figure 3 As shown, in some embodiments, multiple receiving slots 211 are evenly spaced along the circumferential direction of the base plate 21 so that the metal fuel rods 60 are evenly spaced, which facilitates subsequent testing of each metal fuel rod.

[0035] In this embodiment, multiple receiving grooves 211 on the top surface of the base plate 21 are evenly spaced along its circumference, and multiple grooves 231 on the edges of the two support plates 23 are also evenly spaced along their circumference and correspond to the multiple receiving grooves 211, so that multiple metal fuel rods 60 can be fixed to the fuel rod support frame 20 at intervals.

[0036] like Figure 2 and Figure 5 As shown, in some embodiments, the settling device may further include: a heating device 40, which has a heating chamber 41, and a fuel rod support frame 20 is partially housed in the heating chamber 41. The heating device 40 is used to heat the side wall of the metal fuel rod 60, so that the molten liquid sodium rises along the gap between the fuel core and the shell, so that the fuel core continues to settle until the fuel core is submerged in the liquid sodium.

[0037] In this embodiment, after the sodium wire at the bottom of the metal fuel rod 60 has basically melted under the action of the induction heating coil 30, the heating device 40 is turned on to heat the side wall of the metal fuel rod 60, so that the part of the metal fuel rod 60 placed in the heating chamber 41 is heated to above the melting point of sodium, thereby causing the liquid sodium to rise along the gap between the fuel core and the shell, and the fuel core continues to sink until the fuel core is completely immersed in the liquid sodium.

[0038] like Figure 5 As shown, in some embodiments, the heating device 40 may include a housing 42 and a plurality of heating wires 43. The housing 42 is supported on the base 10 and sleeved on the outside of the fuel rod support frame 20, and a heating cavity 41 is formed inside the housing 42. The plurality of heating wires 43 are disposed on the inner surface of the housing 42, with both ends of the heating wires 43 penetrating the housing 42 and extending outside the housing 42 to be connected to an external power source. The heating wires 43 are used to generate heat to heat the metal fuel rod 60, so that the liquid sodium inside the metal fuel rod 60 rises within the tube. The plurality of heating wires 43 are spaced apart along the axial direction of the fuel rod support frame 20, and are independent of each other, used for zoned heating of different areas of the metal fuel rod. After the fuel core 62 inside the metal fuel rod 60 is immersed in the liquid sodium, heating can be stopped in sections. For example, the heating wires 43 may be resistance wires for resistance heating of the metal fuel rod 60.

[0039] In some embodiments, the heating device may further include: a plurality of heating wire interfaces 45, wherein the heating wire interfaces 45 are configured to penetrate the housing 42 and extend outside the housing 42, and one end of the heating wire interface 45 is connected to the heating wire 43, and the other end is connected to an external power source.

[0040] In this embodiment, two heating wire interfaces 45 form a group, and multiple heating wire interfaces 45 are divided into multiple groups, such as... Figure 4As shown, each heating wire interface 45 is connected to both ends of each heating wire 43, so that each heating wire 43 can be turned on and off independently to achieve zoned heating of different areas of the metal fuel rod 60.

[0041] Furthermore, after the fuel core 62 inside the metal fuel rod 60 is completely immersed in liquid sodium, the external power supply to the corresponding heating wires 43 is sequentially turned off in each section, so that each group of heating wires 43 stops heating in turn. This causes the liquid sodium in the metal fuel rod 60 to solidify sequentially, ultimately solidifying the sodium, fuel core 62, and shell 61 together, achieving initial sodium bonding. Compared with stopping the heating of the metal fuel rod simultaneously without sectioning, stopping the heating in sections sequentially reduces the generation of gaps or bubbles during solidification, improves the quality of initial sodium bonding, and provides favorable conditions for subsequent sodium bonding.

[0042] For example, after the fuel core 62 inside the metal fuel rod 60 is completely immersed in liquid sodium, heating can be stopped sequentially from bottom to top so that the liquid sodium in the metal fuel rod 60 solidifies sequentially from the bottom of the metal fuel rod 60 upwards.

[0043] like Figure 5 As shown, in some embodiments, the heating device 40 may further include a heat exchange tube 44, which is disposed inside the housing 42 and spaced apart from the heating wire 43. Both ends of the heat exchange tube 44 extend outside the housing 42 to connect with a coolant source. The heat exchange tube 44 is used to provide a circulation channel for the coolant to cool the liquid sodium after the fuel core 62 is deposited to a predetermined position. At the same time, it causes the internal temperature of the heating device 40 to drop rapidly to a predetermined temperature so that the metal fuel rod 60 is cooled quickly, saving the time that the metal fuel rod 60 waits to be unloaded after settling and improving the working efficiency of the settling process.

[0044] In this embodiment, the housing 42 of the heating device 40 includes an inner housing and an outer housing, which are spaced apart. A heat exchange tube 44 is disposed between the inner housing and the outer housing. Coolant is introduced into the heat exchange tube 44 to forcibly cool the liquid sodium in the metal fuel rod 60. After the heating wire 43 stops heating, the heat exchange tube 44 is turned on to introduce coolant into it, so as to cool the liquid sodium after the fuel core 62 is deposited at a predetermined position, and at the same time reduce the internal temperature of the heating device 40, so that the fuel core 62 drops to room temperature rapidly.

[0045] Furthermore, the coolant introduced into the heat exchange tube 44 is a gas, such as argon, helium, carbon dioxide, nitrogen, etc. This avoids the slowing-down problem that can easily occur when using water as a coolant to cool liquid sodium, and also avoids the radioactive contamination that could result from water leakage. In this embodiment, a gas is used as the coolant to prevent the leakage of radioactive materials.

[0046] In some embodiments, the heating device 40 further includes a heat exchange tube interface 46. The heat exchange tube interface 46 is configured to penetrate the housing 42 and extend outside the housing 42. One end of the heat exchange tube interface 46 is connected to the heat exchange tube 44, and the other end is connected to a coolant source to allow coolant to be introduced into the heat exchange tube.

[0047] In some embodiments, the heating device 40 may further include a temperature measuring unit. The temperature measuring unit is disposed inside the heating device 40 and is used to monitor the internal temperature of the heating device 40 to control the internal temperature of the heating device 40 to be maintained at a predetermined temperature. In some embodiments, the temperature measuring unit may be a thermocouple, which is used to measure the internal temperature of the heating device 40.

[0048] like Figure 5 As shown, in some embodiments, the heating cavity 41 may be provided with through holes 411. Multiple through holes 411 may be provided, and multiple through holes 411 are arranged in an array on the side wall of the heating cavity 41 to facilitate heat dissipation of the heating cavity 41, thereby ensuring that the heating cavity 41 is rapidly cooled to room temperature.

[0049] like Figure 2 As shown, in some embodiments, the settling device may further include: a detection device 50, which is disposed above the heating device 40, for detecting the position of the fuel core 62 in each metal fuel rod 60, so as to determine whether the top of the fuel core 62 has settled to a predetermined position, thereby determining whether to stop heating the metal fuel rod 60.

[0050] In some embodiments, multiple detection devices 50 can be configured, and these devices 50 can be arranged along the circumferential direction of the fuel rod support frame 20 to simultaneously monitor the position of the fuel core 62 in multiple metal fuel rods 60, thereby improving detection efficiency and ensuring the accuracy of detection results. Additionally, the detection devices 50 can be supported above the heating device 40 by an external mechanism, positioning them at a height capable of detecting the position of the fuel core 62 in each metal fuel rod 60. For example, the detection devices 50 can be positioned at the top of the fuel core 62 after it has completely settled, allowing the detection devices 50 to determine whether the fuel core 62 has completely settled.

[0051] like Figure 2 As shown, in some embodiments, the fuel rod support frame 20 is rotatably disposed in the heating device 40 so that each metal fuel rod 60 in the fuel rod support frame 20 is rotated sequentially to a predetermined detection position for detection. The predetermined detection position corresponds to the detection device 50 so that the detection device 50 can sequentially detect the position of the fuel core 62 in each metal fuel rod 60.

[0052] like Figure 2 and Figure 4 As shown, in some embodiments, the base 10 includes a support 12 and a rotating base plate 13. A heating device 40 is supported on the support 12, and the rotating base plate 13 is rotatably mounted on the support 12, with the heating device 40 surrounding the outside of the rotating base plate 13. A fuel rod support frame 20 is detachably mounted on the rotating base plate 13, and the rotating base plate 13 drives the fuel rod support frame 20 to rotate, so that each metal fuel rod in the fuel rod support frame 20 rotates sequentially to the detection position for detection. An electrical connection connector 11 is mounted on the rotating base plate 13 and connected to an external power source to provide power to each induction heating coil 30 in the receiving slot 211, enabling each induction heating coil 30 to heat the bottom end of the metal fuel rod.

[0053] In this embodiment, when the fuel rod support frame 20 is placed on the rotating base plate 13, the electrical connection interface at the bottom of the fuel rod support frame 20 is connected to the electrical connection connector 11 on the rotating base plate 13. At this time, power is supplied to each induction heating coil 30 through the connection between the electrical connection interface and the electrical connection connector 11, so that each induction heating coil 30 can heat the bottom end of the metal fuel rod, causing the sodium wire 63 to melt from the bottom to form liquid sodium, thereby causing the fuel core 62 to gradually sink in the tube shell 61. At the same time, the rotating base plate 13 drives the fuel rod support frame 20 to rotate at a predetermined speed, so that each metal fuel rod 60 rotates sequentially to the detection position, thereby using the detection device 50 to complete the detection of the position of the fuel core 62 in each metal fuel rod 60.

[0054] like Figure 6 As shown, in some embodiments, the detection device 50 may include a moving mechanism 51, a radiation source 52, and an imaging plate 53. The moving mechanism 51 is movably disposed on one side of the fuel rod support frame 20, and the moving direction of the moving mechanism 51 is parallel to the radial direction of the fuel rod support frame 20. The radiation source 52 is used to emit radiation toward the metal fuel rod 60, and the imaging plate 53 is used to receive and image the radiation passing through the metal fuel rod 60. The imaging plate 53 and the radiation source 52 are correspondingly disposed on the moving mechanism 51, and the moving mechanism 51 is used to drive the imaging plate 53 and the radiation source 52 to move.

[0055] When the moving mechanism 51 moves the imaging plate 53 and the radiation source 52 toward the metal fuel rod 60 to the detection position, the imaging plate 53 and the radiation source 52 are located on both sides of the metal fuel rod 60. When the moving mechanism 51 moves the imaging plate 53 and the radiation source 52 away from the fuel rod support frame 20, the fuel rod support frame 20 rotates to rotate another metal fuel rod 60 to the predetermined detection position, thereby completing the detection of all metal fuel rods 60 in sequence.

[0056] In some embodiments, the detection device 50 may further include a transmission connector 54 and a power connector 55. The transmission connector 54 is connected to an external data processing mechanism for outputting imaging data to the external mechanism for processing and recording. The power connector 55 is connected to an external power source to power the detection device 50.

[0057] In this embodiment, the position of the fuel core 62 is detected by online X-ray detection. In some embodiments, the position of the fuel core 62 in the metal fuel rod 60 can be detected by other methods, such as isotope detection, nuclear material detection, and abundance detection.

[0058] The process of settling metal fuel rods using the settling device of this application is further illustrated below with specific embodiments.

[0059] Example 1

[0060] The settling device of this embodiment is used to settling a metal fuel rod 60 with a length of 2775mm. The fuel core 62 of the target metal fuel rod 60 has a length of 1100mm, a diameter of φ6.7mm, and an inner diameter of φ7.7mm for the shell 61. The sodium wire 63 and the fuel core 62 in the metal fuel rod 60 have been filled, and the upper plug 64 has been welded and passed inspection.

[0061] First, the fuel rod support frame 20, fully loaded with metal fuel rods 60, is hoisted onto the rotating base plate 13 of the base 10, so that the quick-connect connector at the top of the base 10 is connected to the quick-connect interface at the bottom of the fuel rod support frame 20.

[0062] Second, turn off the power supply to the heating wire 43 in the heating device 40 to stop heating, turn on the coolant source to allow coolant to flow into the heat exchange tube 44, so that the internal temperature of the heating device 40 is reduced to a predetermined temperature (e.g., 10°C). In this embodiment, a low-temperature thermocouple is used to measure the temperature in the heating device 40.

[0063] Third, power is supplied to the base 10 through the quick-connect interface and quick-connect connector to each induction heating coil 30 to heat the lower end plug 64 of the metal fuel rod 60. The lower end plug 64 conducts heat to melt the solid sodium wire 63 at the bottom. At this time, the heating temperature of the induction heating coil 30 is controlled by thermocouples to be maintained at a certain predetermined temperature (e.g., 250°C).

[0064] Fourth, the detection device 50, which is set at a predetermined height (e.g., 800 mm from the lower end plug of the metal fuel), is turned on to detect the position of the fuel core 62 in each metal fuel rod 60.

[0065] Fifth, as the sodium wire 63 melts, the fuel core 62 in the metal fuel rod 60 gradually sinks. When the detection device 50 shows that all the fuel cores 62 in the metal fuel rod 60 have sunk to the predetermined position, the cooling gas source connected to the heat exchange tube 44 in the heating device 40 is shut off to stop cooling.

[0066] Sixth, turn on the power supply to all the heating wires 43 in the heating device 40 to heat some of the metal fuel rods 60 placed in the heating device 40, and use thermocouples to monitor the temperature of the heating device 40 and control the temperature inside the heating device 40 at a certain predetermined temperature (e.g., 120°C).

[0067] Seventh, at this time, the side wall temperature of the metal fuel rod 60 exceeds the melting point of sodium. The liquid sodium in the metal fuel rod 60 rises along the gap between the fuel core 62 and the shell 61. The fuel core 62 gradually sinks to the bottom of the shell 61 and is immersed in the liquid sodium. At this time, the detection device 50 is used to detect the position of the fuel core 62 in each metal fuel rod 60 and the liquid sodium level.

[0068] Eighth, when the detection device 50 detects that the fuel core 62 in all the metal fuel rods 60 has reached the predetermined position, the power supply to the base 10 is disconnected, and the metal fuel rods 60 are left to stand for a predetermined time (e.g., 3 minutes) so that the liquid sodium at the bottom of the tube shell 61 can solidify preferentially.

[0069] Ninth, turn off the power to each heating wire 43 in the heating device in order from bottom to top, with a predetermined time interval between each two heating wires (e.g., 5 minutes; the time between each two heating wires can also be different. Specifically, a thermocouple can be used to measure the outer wall temperature of the metal fuel rod 60 corresponding to each heating wire, and it is advisable to turn off the power when the outer wall temperature is lower than the melting point of sodium), so that the liquid sodium in the metal fuel rod 60 solidifies sequentially from the bottom of the metal fuel rod 60 upwards.

[0070] Tenth, after all heating wires 43 are turned off, the coolant source is turned on so that the heat exchange tubes 44 in the heating device 40 are circulated with coolant to accelerate the cooling of liquid sodium in the metal fuel rod 60. When the temperature detected by the thermocouple used to detect the temperature in the heating device 40 is lower than the predetermined temperature (e.g., 10°C), the fuel rod support frame 20 is lifted out of the settling device.

[0071] Eleventh, wait for the other fuel rod support frame 20 to be hoisted into the settling equipment for settling treatment.

[0072] Regarding the embodiments of the present invention, it should also be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0073] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A settling device for metal fuel rods, characterized in that, The metal fuel rod includes: a shell, a fuel core, and a sodium wire, wherein the fuel core and the sodium wire are disposed inside the shell, and the fuel core is located above the sodium wire; The settling equipment includes: Base; A fuel rod support frame is detachably supported on the base. The fuel rod support frame has multiple receiving slots that match the ends of the metal fuel rods so that the bottom ends of the metal fuel rods can be inserted into the receiving slots, thereby vertically supporting the metal fuel rods on the fuel rod support frame. Multiple induction heating coils are disposed within the receiving groove. The induction heating coils are used to heat the bottom end of the metal fuel rod, causing the sodium wire to melt from the bottom to form liquid sodium, so that the fuel core gradually sinks within the tube shell.

2. The device according to claim 1, characterized in that, The base is provided with an electrical connection connector on its top, which is used to connect to an external power source. The bottom of the fuel rod support frame is provided with an electrical connection interface, which is connected to each of the induction heating coils and is matched with the electrical connection connector. When the fuel rod support frame is supported on the base, the electrical connection connector is connected to the electrical connection interface to supply power to each of the induction heating coils.

3. The device according to claim 1, characterized in that, The fuel rod support frame includes: The base plate has a plurality of receiving grooves formed on its top surface, the receiving grooves being used to receive the ends of the metal fuel rods; the bottom of the base plate is provided with an electrical connection interface; A support rod is vertically mounted on the base plate, and the metal fuel rod is inserted into the receiving groove parallel to the support rod; At least one support plate is provided at different heights of the support rod at intervals, and the edge of the support plate is formed with a plurality of grooves, which correspond to a plurality of receiving slots for receiving the metal fuel rod.

4. The device according to claim 3, characterized in that, The plurality of receiving slots are evenly spaced along the circumferential direction of the base plate.

5. The device according to any one of claims 1-4, characterized in that, Also includes: A heating device is provided, wherein a heating chamber is formed, and a fuel rod support frame is partially housed within the heating chamber. The heating device is used to heat the sidewall of the metal fuel rod, causing the liquid sodium to rise along the gap between the fuel core and the shell, so that the fuel core continues to sink until the fuel core is submerged in the liquid sodium.

6. The device according to claim 5, characterized in that, The heating device includes: A housing, which is supported on the base and sleeved on the outside of the fuel rod support frame, and the heating chamber is formed inside the housing; Multiple heating wires are disposed on the inner surface of the housing, with both ends of the heating wires penetrating the housing and extending to the outside of the housing for connection to an external power source. The heating wires are used to generate heat to heat the metal fuel rod. The plurality of heating wires are arranged at intervals along the axial direction of the fuel rod support frame, and the plurality of heating wires are independent of each other, for zonal heating of different areas of the metal fuel rod.

7. The device according to claim 6, characterized in that, The heating device also includes: A heat exchange tube is disposed inside the housing and spaced apart from the heating wire. Both ends of the heat exchange tube extend outside the housing to connect with a coolant source. The heat exchange tube is used to provide a circulation channel for the coolant to cool the liquid sodium after the fuel core has been deposited to a predetermined position.

8. The device according to claim 1, characterized in that, Also includes: A detection device is provided above the heating device to detect the position of the fuel core in each of the metal fuel rods, so as to determine whether the top of the fuel core has sunk to a predetermined position.

9. The device according to claim 8, characterized in that, The fuel rod support frame is rotatably disposed in the heating device, so that each of the metal fuel rods in the fuel rod support frame is rotated sequentially to a predetermined detection position for detection, the predetermined detection position corresponding to the detection device.

10. The device according to claim 9, characterized in that, The base includes: The heating device is supported on the support base. A rotating base plate is rotatably mounted on the support base, and the heating device surrounds the outside of the rotating base plate; the fuel rod support frame is detachably mounted on the rotating base plate, and the rotating base plate is used to drive the fuel rod support frame to rotate; an electrical connection connector is mounted on the rotating base plate.

11. The device according to claim 9, characterized in that, The detection device includes: A moving mechanism is movably disposed on one side of the fuel rod support frame, and the moving direction of the moving mechanism is parallel to the radial direction of the fuel rod support frame; A radiation source for emitting radiation toward the metal fuel rod; An imaging plate is used to receive and image the rays passing through the metal fuel rod; the imaging plate and the ray source are correspondingly disposed on the moving mechanism, which is used to move the imaging plate and the ray source. Specifically, when the moving mechanism moves the imaging plate and the radiation source toward the metal fuel rod to the detection position, the imaging plate and the radiation source are located on both sides of the metal fuel rod; when the moving mechanism moves the imaging plate and the radiation source away from the fuel rod support frame, the fuel rod support frame rotates to rotate another metal fuel rod to the predetermined detection position.

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