Sodium charging device and sodium charging method

Abstract

Embodiments of this application relate to the field of equipment or processes for manufacturing nuclear reactor components, specifically to a sodium-filling device and method. The sodium-filling device includes: a sodium-filling assembly, a heating assembly, a vacuum pumping component, a spacer, and an end-plug mounting component. The sodium-filling assembly is configured to fix the fuel rod and add solid sodium into it. The heating assembly is configured to measure temperature and perform segmented heating of the fuel rod to melt the solid sodium into liquid sodium and to allow the liquid sodium to solidify segmentally. The vacuum pumping component evacuates the interior of the fuel rod to remove gas from the liquid sodium. The end-plug mounting component is configured to install and remove the spacer and install the end plug, and the spacer is configured to reduce the evaporation of liquid sodium in the fuel rod during segmented solidification. This configuration allows the sodium to uniformly fuse and fill the tiny gaps in the fuel rod after melting, reducing bubbles generated after the liquid sodium solidifies.

Description

Technical Field

[0001] Embodiments of this application relate to the field of equipment or processes for manufacturing nuclear reactor components, and more specifically to a sodium-filling device and a sodium-filling method. 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 rods of a sodium-cooled fast reactor are filled with a sodium layer located between the fuel core and the cladding. This layer helps to dissipate heat from the fuel rods, allowing for better thermal conversion between the fuel rods and the liquid sodium flowing in the primary circuit.

[0004] There are still some shortcomings in the process of filling sodium into the fuel rods of sodium-cooled fast reactors. Summary of the Invention

[0005] 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.

[0006] In a first aspect, embodiments of this application provide a sodium-filling device suitable for filling sodium into fuel rods of a sodium-cooled fast reactor. The device includes: a sodium-filling assembly, a heating assembly, a vacuum pumping component, a spacer, and an end-plug mounting component. The sodium-filling assembly is configured to fix the fuel rods and add solid sodium into them. The heating assembly is configured to measure temperature and perform segmented heating of the fuel rods to melt the solid sodium into liquid sodium and to allow the liquid sodium to solidify in segments. The vacuum pumping component is disposed within the sodium-filling assembly and configured to evacuate the interior of the fuel rods to extract gas from the liquid sodium. The end-plug mounting component is configured to install and remove the spacer and install the end-plugs on the fuel rods. The spacer is configured to reduce the evaporation of liquid sodium in the fuel rods during segmented solidification. The sodium-filling assembly is also configured to form a closed space capable of regulating the atmosphere and temperature, allowing the fuel rods to be filled with sodium within the closed space.

[0007] The embodiments of this application use a heating assembly to heat the fuel rod in sections, allowing the liquid sodium to solidify in sections. By setting up a spacer, the amount of liquid sodium evaporating from the fuel rod during the section solidification process is reduced. At the same time, a vacuum pump is set up to evacuate the inside of the fuel rod, so that the gas in the liquid sodium is extracted. This allows the sodium to be uniformly fused and filled into the tiny gaps in the fuel rod after melting, reducing the number of bubbles generated after the liquid sodium solidifies.

[0008] Secondly, embodiments of this application provide a sodium-filling method suitable for filling sodium into fuel rods of a sodium-cooled fast reactor, comprising the following steps: S10: adding solid sodium into the fuel rods; S20: heating the fuel rods in sections to melt the solid sodium into liquid sodium; S30: during the heating process in step S20, evacuating the inside of the fuel rods to extract the gas in the liquid sodium; S40: stopping the evacuation and cooling the fuel rods to solidify the liquid sodium in sections; S50: installing end plugs on the fuel rods.

[0009] The embodiments of this application heat the fuel rod in sections and evacuate the inside of the fuel rod to extract the gas in the liquid sodium. This allows the sodium to melt and uniformly fuse and fill the tiny gaps in the fuel rod, and enables the liquid sodium to solidify in sections, reducing the bubbles generated after solidification.

[0010] Thirdly, embodiments of this application provide a sodium-filling method suitable for filling sodium into fuel rods of a sodium-cooled fast reactor. This method uses the sodium-filling device provided in the first aspect of this application to fill the fuel rods with sodium, comprising the following steps: S10: adding solid sodium into the fuel rods using the sodium-filling component of the sodium-filling device; S20: heating the fuel rods in stages using the heating component of the sodium-filling device to melt the solid sodium into liquid sodium; S30: during the heating process in step S20, evacuating the inside of the fuel rods using the vacuuming component of the sodium-filling device to extract the gas from the liquid sodium; S40: stopping the vacuuming, cooling the fuel rods, and installing a placeholder on the fuel rods using an end-plug mounting component to reduce the evaporation of liquid sodium during staged solidification; S50: removing the placeholder from the fuel rods and installing an end plug using the end-plug mounting component.

[0011] The embodiments of this application use a heating assembly to heat the fuel rod in sections, enabling the liquid sodium to solidify in sections. A spacer reduces the evaporation of liquid sodium in the fuel rod during the section solidification process. At the same time, a vacuuming assembly is used to evacuate the inside of the fuel rod, so that the gas in the liquid sodium is extracted. This allows the sodium to be uniformly fused and filled into the tiny gaps in the fuel rod after melting, reducing the bubbles generated after the liquid sodium solidifies. Attached Figure Description

[0012] 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.

[0013] Figure 1 This is a schematic diagram of the sodium filling device provided in an embodiment of this application, with some parts omitted.

[0014] 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.

[0015] Explanation of reference numerals in the attached figures: 10. Sodium filling assembly; 11. Sodium filling component; 12. Atmosphere control component; 13. Conveying and fixing component; 20. Heating components; 30. Fuel rods. Detailed Implementation

[0016] 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.

[0017] 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.

[0018] When filling sodium into the fuel rods of a sodium-cooled fast reactor, the large surface tension of liquid sodium makes it easy for uneven filling to occur between the fuel core and the cladding. This can result in incomplete fusion or the presence of air bubbles in the sodium layer, leading to uneven heat transfer and the risk of cladding failure due to localized overheating.

[0019] To address the aforementioned problems, embodiments of this application provide a sodium-filling device suitable for filling sodium into the fuel rods of a sodium-cooled fast reactor. See [link to relevant documentation]. Figure 1 , Figure 1This is a schematic diagram of the sodium filling device provided in an embodiment of this application, omitting some structural elements. The sodium filling device may include: a sodium filling assembly 10, a heating assembly 20, a vacuum pump (not shown), a spacer (not shown), and an end plug mounting component (not shown). The sodium filling assembly 10 is configured to fix the fuel rod 30 and add solid sodium into the fuel rod 30. The heating assembly 20 is configured to measure the temperature and perform segmented heating on the fuel rod 30 to melt the solid sodium into liquid sodium and to allow the liquid sodium to solidify in segments. The vacuum pump is disposed in the sodium filling assembly 10 and configured to evacuate the interior of the fuel rod 30 to extract the gas in the liquid sodium. The end plug mounting component is configured to install and remove the spacer and install the end plug on the fuel rod 30. The spacer is configured to reduce the evaporation of liquid sodium in the fuel rod 30 during segmented solidification. The sodium filling assembly 10 is also configured to form a closed space that can regulate the atmosphere and temperature, allowing the fuel rod 30 to be filled with sodium within the closed space.

[0020] The embodiments of this application use a heating assembly 20 to heat the fuel rod 30 in segments, allowing the liquid sodium to solidify in segments. By setting up a spacer, the amount of liquid sodium evaporating from the fuel rod 30 during the segmented solidification process is reduced. At the same time, a vacuum pump is set up to evacuate the inside of the fuel rod 30, so that the gas in the liquid sodium is extracted. This allows the sodium to be uniformly fused and filled into the tiny gaps in the fuel rod 30 after melting, reducing the bubbles generated after the liquid sodium solidifies.

[0021] In some embodiments, the sodium filling assembly 10 may include an atmosphere control element 12, a sodium filling element 11, and a conveying and fixing element 13. The atmosphere control element 12 is configured to form a closed space and is capable of controlling the atmosphere and temperature within the closed space. The conveying and fixing element 13 is configured to be controllably connected to the atmosphere control element 12 to convey the fuel rod 30 to the closed space and is capable of fixing the fuel rod 30. The sodium filling element 11 is configured to add solid sodium into the fuel rod 30 within the closed space.

[0022] This configuration allows the fuel rod 30 to be conveyed by the conveyor fixture 13 to an enclosed space for sodium filling under controlled atmosphere and temperature.

[0023] In some embodiments, the conveying fixture 13 may include a conveying member, a fixture, and an exhaust member; the conveying member is configured to be controllably connected to the atmosphere control member 12 and to convey the fuel rod 30 to the enclosed space, the fixture is configured to fix the fuel rod 30, and the exhaust member is configured to exhaust air from the conveying member to create an atmosphere inside the conveying member that is the same as that inside the enclosed space.

[0024] This configuration allows the interior of the transporter to form the same atmosphere as the enclosed space, ensuring that the atmosphere in the enclosed space is not disrupted by the transport fuel rod 30.

[0025] In some embodiments, the heating assembly 20 may include a heating element and a temperature measuring element. The heating element is configured to move relative to the conveying fixture 13 of the sodium filling assembly 10 to heat the fuel rod 30 in stages and to solidify the liquid sodium in stages. The temperature measuring element is configured to measure the temperature of the area where the heating element heats in stages to determine whether the solid sodium has melted into liquid sodium.

[0026] With this configuration, the heating element moves relative to the conveying fixture 13, enabling the heating element to heat the fuel rod 30 in segments and to solidify the liquid sodium in segments. By measuring the temperature of the segmented heating area, it is determined whether the solid sodium has melted into liquid sodium, thus enabling it to determine whether the heating element needs to move relative to the next area for heating.

[0027] In such an embodiment, segmented heating can be performed by heating the fuel rod 30 from top to bottom, thus creating space in the fuel rod to accommodate the volume of solid sodium as it melts and expands.

[0028] In some embodiments, the end plug mounting member can be disposed in an enclosed space and configured to install a placeholder for the upper opening of the fuel rod 30 after all the solid sodium in the fuel rod 30 has melted, and to remove the placeholder after all the liquid sodium in the fuel rod 30 has solidified, thereby installing an end plug for the upper opening of the fuel rod 30.

[0029] This configuration allows the fuel rod 30 to be fitted with a spacer in a closed space to reduce the evaporation of liquid sodium in the fuel rod 30. After all the liquid sodium has solidified, the spacer is removed and an end plug is installed to complete the sodium filling process.

[0030] In such an embodiment, the mounting end plug can be installed by welding.

[0031] In some embodiments, the length of the occupant extending axially along the fuel rod 30 may be greater than the length of the end plug extending axially along the fuel rod 30.

[0032] With this configuration, the spacer occupies more space in the fuel rod 30, resulting in less remaining space in the fuel rod 30, reducing the space for sodium vapor, and thus reducing the amount of liquid sodium evaporation.

[0033] In some embodiments, the vacuum pump can be configured to simultaneously evacuate the inside of the fuel rod 30 through the upper opening of the fuel rod 30 while the heating assembly 20 heats the fuel rod 30 from top to bottom, so that gas is extracted.

[0034] This design allows the gas in the liquid sodium to be extracted, enabling the sodium to melt and uniformly fuse and fill the tiny gaps in the fuel rod 30, thus reducing the bubbles generated after the liquid sodium solidifies.

[0035] In some embodiments, the vacuuming device may also be configured to stop vacuuming after all the solid sodium inside the fuel rod 30 has melted, in order to reduce the evaporation of liquid sodium in the fuel rod 30.

[0036] This design avoids removing the sodium vapor formed during heating after the gas in the liquid sodium is extracted, thus preventing a reduction in the sodium filling capacity.

[0037] In some embodiments, the heating assembly 20 may also be configured to move from bottom to top relative to the fuel rod 30 after the solid sodium in the fuel rod 30 has completely melted into liquid sodium, so that the liquid sodium begins to solidify from the bottom end of the fuel rod 30, thus preventing gas from remaining in the solidified sodium.

[0038] This design allows gas to escape through the upper layer of liquid sodium, preventing the upper layer of liquid sodium from solidifying first and causing gas in the unsolidified liquid sodium below to remain trapped in the solidified sodium.

[0039] Embodiments of this application also provide a sodium-filling method suitable for filling sodium into fuel rods 30 of a sodium-cooled fast reactor, which may include the following steps: S10: adding solid sodium into fuel rods 30; S20: heating fuel rods 30 in stages to melt solid sodium into liquid sodium; S30: during the heating process in step S20, evacuating the inside of fuel rods 30 to extract gas from the liquid sodium; S40: stopping the evacuation and cooling fuel rods 30 to solidify liquid sodium in stages; S50: installing end plugs on fuel rods 30.

[0040] The embodiments of this application heat the fuel rod 30 in sections and evacuate the inside of the fuel rod 30 to extract the gas in the liquid sodium. This allows the sodium to melt and uniformly fuse and fill the tiny gaps in the fuel rod 30, and enables the liquid sodium to solidify in sections, reducing the bubbles generated after solidification.

[0041] In some embodiments, during step S30, the fuel rod 30 can be heated in segments from the upper end to the lower end during the heating process.

[0042] This design allows for space to accommodate the volume of solid sodium as it expands after melting.

[0043] In some embodiments, during step S40, the liquid sodium at the lower end of the fuel rod 30 can be solidified first during the cooling process to avoid gas residue in the liquid sodium.

[0044] This design allows gas to escape through the upper layer of liquid sodium, preventing the upper layer of liquid sodium from solidifying first and causing gas in the unsolidified liquid sodium below to remain trapped in the solidified sodium.

[0045] In some embodiments, during step S40, a spacer can be installed at the upper opening of the fuel rod 30 during the cooling process to reduce the evaporation of liquid sodium, and the spacer can be removed after all the liquid sodium has solidified.

[0046] This configuration reduces the evaporation of liquid sodium in fuel rod 30, and allows for the removal of the occupant and installation of the end plug after all the liquid sodium has solidified, thus completing the sodium filling process.

[0047] The embodiments of this application also provide a sodium-filling method, applicable to filling sodium into the fuel rods 30 of a sodium-cooled fast reactor. This method uses the sodium-filling device of any of the foregoing embodiments to fill the fuel rods 30 with sodium, and may include the following steps: S10: Adding solid sodium to the fuel rods 30 using the sodium-filling component 10 of the sodium-filling device; S20: Heating the fuel rods 30 in stages using the heating component 20 of the sodium-filling device to melt the solid sodium into liquid sodium; S30: During the heating process in step S20, evacuating the interior of the fuel rods 30 using the vacuuming component of the sodium-filling device to extract the gas from the liquid sodium; S40: Stopping the vacuuming, cooling the fuel rods 30, and installing a placeholder on the fuel rods 30 using an end-plug mounting component to reduce the evaporation of liquid sodium during staged solidification; S50: Removing the placeholder from the fuel rods 30 and installing an end plug using the end-plug mounting component.

[0048] In the embodiments of this application, the fuel rod 30 is heated in segments by the heating component 20, and the liquid sodium is solidified in segments. The spacer reduces the amount of liquid sodium evaporating in the fuel rod 30 during the segmented solidification process. At the same time, the vacuum component is used to evacuate the inside of the fuel rod 30 so that the gas in the liquid sodium is extracted, so that the sodium can be uniformly fused and filled into the tiny gaps in the fuel rod 30 after melting, reducing the bubbles generated after the liquid sodium solidifies.

[0049] In some embodiments, during step S20, the heating component 20 can move relative to the fuel rod 30 during the heating process, and heat the fuel rod 30 in segments from the upper end to the lower end of the fuel rod 30.

[0050] This design allows for space in the fuel rods to accommodate the volume of solid sodium as it melts and expands.

[0051] In some embodiments, when the vacuum pump evacuates the interior of the fuel rod 30, the vacuum level inside the fuel rod 30 can be no less than 0.001 Pa, and the continuous operating time of the vacuum pump is no less than 5 hours. This configuration allows the gas in the liquid sodium within the fuel rod 30 to be extracted.

[0052] In some embodiments, when the heating assembly 20 heats the fuel rod 30, the maximum heating temperature can be no less than 750°C, the length of the constant temperature zone is no less than 1.5m, the temperature difference between different locations within the constant temperature zone does not exceed ±3°C, the temperature fluctuation at each measuring point does not exceed ±1°C, and the continuous working time of the heating assembly 20 is no less than 5 hours. This configuration ensures that the solid sodium in the fuel rod 30 can melt uniformly.

[0053] In some embodiments, during step S40, the temperature of the fuel rod 30 can be between 50°C and 150°C during the cooling process, with a temperature gradient of not less than 20°C / cm. This configuration allows the liquid sodium in the fuel rod 30 to solidify in stages.

[0054] 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.

[0055] The above description is merely a specific embodiment 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 sodium-filling device suitable for filling sodium into fuel rods of a sodium-cooled fast reactor, characterized in that, It includes: Sodium filling assembly, heating assembly, vacuuming assembly, spacer assembly, and end plug mounting assembly. The sodium filling assembly is configured to fix the fuel rod and add solid sodium into the fuel rod. The heating assembly is configured to measure temperature and perform segmented heating of the fuel rod to melt the solid sodium into liquid sodium and to solidify the liquid sodium in segments. The vacuum pumping component is disposed on the sodium filling assembly and is configured to evacuate the interior of the fuel rod, thereby extracting the gas from the liquid sodium. The end plug mount is configured to install and remove the occupant and install the end plug for the fuel rod. The spacer is configured to reduce the evaporation of liquid sodium in the fuel rod during the segmented solidification process. The sodium filling assembly is also configured to form a closed space capable of regulating the atmosphere and temperature, allowing the fuel rod to be filled with sodium within the closed space.

2. The apparatus according to claim 1, characterized in that, The sodium filling assembly includes an atmosphere control component, a sodium filling component, and a conveying and fixing component. The atmosphere control element is configured to form the enclosed space and is capable of controlling the atmosphere and temperature within the enclosed space. The conveying and fixing component is configured to be controllably connected to the atmosphere control component to convey the fuel rod into the enclosed space and to secure the fuel rod. The sodium filling device is configured to add solid sodium into the fuel rod within the enclosed space.

3. The apparatus according to claim 2, characterized in that, The conveying fixture includes a conveying component, a fixing component, and an air extraction component; The conveyor is configured to be controllably connected to the atmosphere control unit and capable of delivering the fuel rods to the enclosed space. The fastener is configured to secure the fuel rod. The air extraction device is configured to extract air from the conveyor to create an atmosphere inside the conveyor that is identical to that in the enclosed space.

4. The apparatus according to claim 1, characterized in that, The heating assembly includes a heating element and a temperature measuring element. The heating element is configured to move relative to the conveying and fixing element of the sodium filling assembly in order to heat the fuel rod in stages and allow the liquid sodium to solidify in stages. The temperature measuring element is configured to measure the temperature of the area where the heating element performs segmented heating, in order to determine whether the solid sodium has melted into liquid sodium.

5. The apparatus according to claim 1, characterized in that, The end plug mounting component is disposed in the enclosed space and is configured to install the occupant for the upper opening of the fuel rod after all the solid sodium in the fuel rod has melted, and to remove the occupant for the upper opening of the fuel rod after all the liquid sodium in the fuel rod has solidified, thereby installing the end plug for the upper opening of the fuel rod.

6. The apparatus according to claim 1, characterized in that, The length of the occupant extending axially along the fuel rod is greater than the length of the end plug extending axially along the fuel rod.

7. The apparatus according to claim 1, characterized in that, The vacuum pump is configured such that when the heating assembly heats the fuel rod from top to bottom, the vacuum pump simultaneously evacuates the inside of the fuel rod through the upper opening of the fuel rod, so that the gas is extracted.

8. The apparatus according to claim 7, characterized in that, The vacuum pump is also configured to stop pumping vacuum after all the solid sodium inside the fuel rod has melted, in order to reduce the evaporation of liquid sodium in the fuel rod.

9. The apparatus according to claim 1, characterized in that, The heating assembly is also configured to move from bottom to top relative to the fuel rod after the solid sodium in the fuel rod has completely melted into liquid sodium, so that the liquid sodium begins to solidify from the bottom of the fuel rod, thus preventing the gas from remaining in the solidified sodium.

10. A sodium-filling method, applicable to filling sodium into fuel rods of a sodium-cooled fast reactor, characterized in that, Includes the following steps: S10: Add solid sodium to the fuel rod; S20: Heating the fuel rod in stages to melt the solid sodium into liquid sodium; S30: During the heating process described in step S20, a vacuum is drawn inside the fuel rod to extract the gas from the liquid sodium. S40: Stop vacuuming and cool the fuel rod to allow the liquid sodium to solidify in stages; S50: Install end plugs on the fuel rods.

11. The method according to claim 10, characterized in that, In step S30 During the heating process, the fuel rod is heated in sections from the upper end to the lower end.

12. The method according to claim 10, characterized in that, In step S40 During the cooling process, the liquid sodium at the lower end of the fuel rod is solidified first to prevent gas residue from remaining in the liquid sodium.

13. The method according to claim 10, characterized in that, In step S40 During the cooling process, a spacer is installed at the upper opening of the fuel rod to reduce the evaporation of the liquid sodium, and the spacer is removed after all the liquid sodium has solidified.

14. A sodium-filling method, suitable for filling sodium into fuel rods of a sodium-cooled fast reactor, characterized in that, The process of filling the fuel rod with sodium using the sodium filling device according to any one of claims 1-9 includes the following steps: S10: Solid sodium is added to the fuel rod using the sodium-filling component of the sodium-filling device; S20: The fuel rod is heated in stages using the heating component of the sodium charging device to melt the solid sodium into liquid sodium; S30: During the heating process described in step S20, the vacuuming component of the sodium filling device is used to evacuate the inside of the fuel rod so that the gas in the liquid sodium is extracted. S40: Stop vacuuming, cool the fuel rod, and install the placeholder on the fuel rod using the end plug mounting piece to reduce the evaporation of the liquid sodium during the staged solidification process; S50: Remove the occupant from the fuel rod and install the end plug using the end plug mounting device.

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