A fuel rod and end plug welding chamber

Abstract

A kind of for fuel rod and end plug welding chamber, including cavity shell, tungsten electrode adjusting device is installed in the top of cavity shell by tungsten electrode adjusting device fixing plate, welding torch fixing mechanism is installed in the side of tungsten electrode adjusting device by guide rail, and welding torch passes through welding torch fixing mechanism, lower end is in-depth to cavity shell, the lower end of welding torch is installed tungsten electrode, and cladding tube, end plug are welded;Welding torch fixing mechanism moves up and down by guide rail;Cavity shell left-right symmetrical side opening, in left side, rotating shaft is connected with toothed belt wheel by conical tensioning shaft sleeve, and rotating shaft passes through toothed belt wheel, then passes through clamping mechanism, rotating shaft is rotated by toothed belt wheel, to further drive clamping mechanism rotation;Rotating belt is engaged with toothed belt wheel by gear, and the other end of rotating belt is connected with the output shaft of rotating motor, to drive rotating belt, toothed belt wheel, rotating shaft rotation by the rotation of rotating motor.

Description

Technical Field

[0001] This invention relates to the field of nuclear reactor component manufacturing technology, specifically to a welding chamber for fuel rods and end plugs. Background Technology

[0002] The dummy fuel rod is a key inactive component of the fuel assembly. Its main function is to replace the actual fuel rods in the fuel assembly, maintaining structural stiffness and flow field distribution. Therefore, the welding quality of the dummy fuel rod is required to withstand the high-temperature and high-radiation working environment in the process.

[0003] The existing technology has the following problems: 1) Insufficient sealing performance, making it difficult to stabilize the welding environment. The welding chamber needs to operate under inert gas protection to avoid high-temperature metal oxidation. However, traditional sealing structures are prone to failure after long-term use—rubber seals gradually harden and crack under high temperatures and radiation, leading to gas leakage. During welding, fluctuations in oxygen content can cause oxide spots on the weld surface and internal porosity, severely affecting sealing performance. Even more challenging is the fact that the placeholder rod typically requires rotary welding, and dynamic sealing at the rotating shaft is particularly difficult. Leaked gas not only wastes expensive high-purity argon but also introduces impurities, resulting in inconsistent weld quality.

[0004] 2) Poor adaptability to different chambers, and time-consuming and labor-intensive adjustments during remodeling. The placeholder bar can be several meters long, but only tens of millimeters in diameter. This slender structure presents a significant challenge to the design of the welding chamber. Existing equipment is often only compatible with fixed specifications; if a placeholder bar of a different size is used, the existing equipment cannot complete the welding process. In addition, due to the limited internal space of the chamber, the range of motion of the welding head is restricted, making it difficult to operate precisely at certain welding positions and affecting the consistency of the weld.

[0005] 3) The observation window is blurry, making it difficult to monitor the process. During high-temperature welding, metal vapor and spatter particles continuously accumulate on the observation window. After only a few welds, operators can no longer clearly observe the state of the molten pool and must stop the machine for cleaning. Even more seriously, spatter from certain high-melting-point metals (such as tungsten) can adhere firmly to the inner wall of the welding chamber, making it difficult to remove. Over time, it may even peel off, contaminating subsequent welding processes. Summary of the Invention

[0006] The purpose of this invention is to address a series of technical pain points in the existing welding process of fuel rod end plugs, such as insufficient sealing performance, poor adaptability, and difficult maintenance, and to provide a welding chamber for fuel rods and end plugs.

[0007] The technical solution of the present invention is as follows: a welding chamber for fuel rods and end plugs includes a chamber shell, a tungsten electrode adjustment device mounted on the top of the chamber shell via a tungsten electrode adjustment device fixing plate, a welding torch fixing mechanism mounted on the side of the tungsten electrode adjustment device via a guide rail, and a welding torch passing through the welding torch fixing mechanism with its lower end extending into the chamber shell. A tungsten electrode is installed at the lower end of the welding torch for welding the cladding tube and end plug; the welding torch fixing mechanism moves up and down via the guide rail. The outer shell of the cavity has symmetrical openings on the left and right sides. On the left side, the rotating shaft is connected to the toothed pulley through a conical tensioning bushing. The rotating shaft passes through the toothed pulley and then through the clamping mechanism. The toothed pulley drives the rotating shaft to rotate, which in turn drives the clamping mechanism to rotate. The rotating belt is meshed with the toothed pulley through gears, and the other end of the rotating belt is connected to the output shaft of the rotary motor. Thus, the rotation of the rotary motor drives the rotating belt, the toothed pulley, and the rotating shaft to rotate. The cladding tube is inserted into the rotating shaft, extending from the left end into the outer shell of the cavity, and its right end exits the rotating shaft. The right end of the cladding tube is inserted into the end plug and connected to the tooling at the tail of the end plug. The tungsten electrode at the lower end of the welding torch is matched with the connection between the cladding tube and the end plug, and the connection between the cladding tube and the end plug is welded through the tungsten electrode. On the right side of the cavity shell, the end plug tail tooling enters from the right side of the cavity shell. The end plug tail tooling is connected to the toothed pulley through a conical tensioning bushing, and the end plug tail tooling passes through the toothed pulley, which drives the end plug tail tooling to rotate.

[0008] A position sensor is also installed on the tungsten electrode adjustment device.

[0009] An indexing plate is installed inside the clamping mechanism. The toothed belt pulley drives the rotating shaft to rotate, which in turn drives the clamping mechanism and the indexing plate to rotate. The rotation angle is determined by the indexing plate.

[0010] Between the clamping mechanism and the toothed pulley, there is a rotating shaft fixing device, through which the rotating shaft passes; the rotating shaft fixing device is installed on the rotating shaft fixing support device.

[0011] On the right side of the cavity shell, symmetrically arranged with respect to the left side of the cavity shell, the end plug tail tooling replaces the rotating shaft.

[0012] Because the carbon brush is in contact with the conductive device, and the conductive device is in contact with the end plug tail tooling, a stable current is provided to the end plug tail tooling. The end plug tail tooling serves as the negative electrode for welding, while the tungsten electrode at the lower end of the welding torch serves as the positive electrode for welding.

[0013] At the right end of the cladding tube, a gas balancing device is installed via a bracket. Inert gas is introduced into the gas balancing device and discharged through the vent, thus providing gas protection for the welding position.

[0014] The outer shell of the cavity is equipped with viewing windows. There are multiple viewing windows, and an automatic weld monitoring device is installed in one of the viewing windows.

[0015] The rotating shaft is fixed and supported, and the cavity shell is mounted on the base plate.

[0016] A gas exchange device is installed on the outer shell of the cavity to facilitate gas exchange between the inside and outside of the cavity.

[0017] The significant advantages of this invention are: 1) Welding quality has been significantly improved a. The composite sealing system reduces the leakage rate to 1×10⁻⁶. -8 Pa·m 3 / s (traditional technology 1×10 -5 ).

[0018] b. The oxygen content of the weld is stably controlled below 50ppm (original process 200-500ppm). c. The porosity defect rate decreased from 8% to 0.3% (X-ray inspection data). 2) Increased production efficiency a. Specification switching time reduced from 240 minutes to 22 seconds b. Compatibility expanded to Φ15-60mm (originally only compatible with ±2mm deviation). 4. Quantitative Analysis of Economic Benefits (1) Direct cost savings a. Inert gas consumption is reduced by 42% (saving approximately 150,000 yuan of high-purity argon per year).

[0019] b. Electrode lifespan extended by 140% (annual tungsten electrode procurement volume reduced by 35,000 units).

[0020] (2) Implicit benefits a. Quality loss costs decreased by 87% (annual reduction of waste disposal costs by 800,000 yuan).

[0021] b. Equipment utilization rate increased by 35% (equivalent to adding the capacity of 1.2 units of equipment). Attached Figure Description

[0022] Figure 1 Schematic diagram of the overall structure for welding chamber between fuel rods and end plugs; Figure 2 Schematic diagram of a high-precision tungsten electrode automatic adjustment device; Figure 3 Schematic diagram of the casing tube clamping mechanism; Figure 4 Schematic diagram of the tooling at the end of the plug; The markings in the diagram and their corresponding component names are as follows: 1. Rotary shaft fixing support device; 2. Clamping mechanism; 3. Rotary shaft fixing device; 4. Toothed pulley; 5. Rotary belt; 6. Viewing window; 7. Welding torch fixing mechanism; 8. Welding torch; 9. Tungsten electrode adjusting device; 10. Conductive device; 11. Carbon brush; 12. Gas exchange device; 13. Cavity shell; 14. Automatic weld monitoring device; 15. Base plate; 16. Rotary motor; 17. Position sensor; 18. Tungsten electrode adjusting device fixing plate; 19. Guide rail; 21. Indexing plate; 22. Rotary shaft; 23. Sheath tube; 24. End plug; 25. End plug tail tooling; 26. Vent; 27. Gas balance device; 28. Bracket; 29. ​​Conical tensioning bushing. Detailed Implementation

[0023] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0024] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items.

[0025] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this application, and similarly, second may also be referred to as first.

[0026] The specific technical content of the present invention will now be described with reference to the accompanying drawings; A welding chamber for fuel rods and end plugs includes a chamber shell 13, a tungsten electrode adjustment device 9 mounted on the top of the chamber shell 13 via a tungsten electrode adjustment device fixing plate 18, a welding torch fixing mechanism 7 mounted on the side of the tungsten electrode adjustment device 9 via a guide rail 19, and a welding torch 8 passing through the welding torch fixing mechanism 7 with its lower end extending into the chamber shell 13. A tungsten electrode is installed at the lower end of the welding torch 8 for welding the cladding tube 23 and the end plug 24. The welding torch fixing mechanism 7 moves up and down via the guide rail 19, and a position sensor 17 is also installed on the tungsten electrode adjustment device 9. The outer shell 13 of the cavity has symmetrical openings on the left and right sides. On the left side, the rotating shaft 22 is connected to the toothed pulley 4 through the conical tensioning bushing 29. The rotating shaft 22 passes through the toothed pulley 4 and then through the clamping mechanism 2. The clamping mechanism 2 has an indexing plate 21 installed inside. The toothed pulley 4 drives the rotating shaft 22 to rotate, which in turn drives the clamping mechanism 2 and the indexing plate 21 to rotate. The rotation angle is determined by the indexing plate 21.

[0027] Between the clamping mechanism 2 and the toothed pulley 4, there is a rotating shaft fixing device 3, through which the rotating shaft 22 passes; The rotating shaft fixing device 3 is installed on the rotating shaft fixing support device 1. The rotating belt 5 and the toothed pulley 4 are engaged by gears, and the other end of the rotating belt 5 is connected to the output shaft of the rotating motor 16. Thus, the rotation of the rotating motor 16 drives the rotating belt 5, the toothed pulley 4, and the rotating shaft 22 to rotate. On the right side of the cavity housing 13, symmetrically arranged with respect to the left side, the end plug tail tool 25 replaces the rotating shaft 22, passing through the right side of the cavity housing 13. The end plug tail tool 25 is connected to the toothed pulley 4 through a conical tensioning bushing 29, and the end plug tail tool 25 passes through the toothed pulley 4, which drives the end plug tail tool 25 to rotate. The right end of the end plug tail tool 25 passes through the conductive device 10, and a carbon brush 11 is installed on the conductive device 10. The carbon brush 11 is connected to the ground wire of the power supply. Since the carbon brush 11 is in contact with the conductive device 10, the conductive device 10 is in contact with the end plug tail tool 25, thereby providing a stable current to the end plug tail tool 25. The end plug tail tool 25 serves as the negative electrode for welding, while the tungsten electrode at the lower end of the welding torch 8 serves as the positive electrode for welding. like Figure 4 As shown, the casing tube 23 is inserted into the rotating shaft 22, extending from the left end into the outer shell 13 of the cavity, and the rotating shaft 22 is exited from the right end. The right end of the casing tube 23 is inserted into the end plug 24 and connected to the end plug tail tool 25. The tungsten electrode at the lower end of the welding torch 8 is matched with the connection between the casing tube 23 and the end plug 24, and the connection between the casing tube 23 and the end plug 24 is welded through the tungsten electrode. At the right end of the cladding tube 23, a gas balancing device 27 is installed via a bracket 28. Inert gas is introduced into the gas balancing device 27 and discharged through the vent 26, thereby providing gas protection for the welding position. A viewing window 6 is installed on the outside of the cavity shell 13. The connection between the shell tube 23 and the end plug 24, i.e. the welding position, can be observed through the viewing window 6. There are multiple viewing windows 6. An automatic weld monitoring device 14 is installed at one of the viewing windows 6 to monitor the welding quality. The rotating shaft fixing support device 1 and the cavity shell 13 are mounted on the base plate 15; A gas exchange device 12 is installed on the outer shell 13 of the cavity, and gas exchange is carried out inside and outside the outer shell 1 through the gas exchange device 12. The welding work is completed. After welding is completed, the motor automatically stops rotating, the clamping mechanism releases its grip, and the rear feeding mechanism automatically conveys the fuel rods to the outside of the welding room for the next process.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0029] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0030] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0031] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.

Claims

1. A welding chamber for fuel rods and end plugs, characterized in that: The assembly includes a cavity shell (13), a tungsten electrode adjustment device (9) mounted on the top of the cavity shell (13) via a tungsten electrode adjustment device fixing plate (18), a welding torch fixing mechanism (7) mounted on the side of the tungsten electrode adjustment device (9) via a guide rail (19), and a welding torch (8) passing through the welding torch fixing mechanism (7), with its lower end extending into the cavity shell (13). A tungsten electrode is installed at the lower end of the welding torch (8) to weld the casing tube (23) and the end plug (24). The welding torch fixing mechanism (7) moves up and down via the guide rail (19). The outer shell of the cavity (13) has symmetrical openings on the left and right sides. On the left side, the rotating shaft (22) is connected to the toothed pulley (4) through the conical tensioning bushing (29), and the rotating shaft (22) passes through the toothed pulley (4) and then through the clamping mechanism (2). The toothed pulley (4) drives the rotating shaft (22) to rotate, which in turn drives the clamping mechanism (2) to rotate. The rotating belt (5) is meshed with the toothed pulley (4) through gears, and the other end of the rotating belt (5) is connected to the output shaft of the rotary motor (16). Thus, the rotation of the rotary motor (16) drives the rotating belt (5), the toothed pulley (4), and the rotating shaft (22) to rotate. The cladding tube (23) is inserted into the rotating shaft (22), extending from the left end to the outer shell of the cavity (13), and the rotating shaft (22) is exited from the right end. The right end of the cladding tube (23) is inserted into the end plug (24) and connected to the end plug tail tool (25). The tungsten electrode at the lower end of the welding torch (8) is matched with the connection between the cladding tube (23) and the end plug (24), and the connection between the cladding tube (23) and the end plug (24) is welded through the tungsten electrode. On the right side of the cavity shell (13), the end plug tail tool (25) enters from the right side of the cavity shell (13). The end plug tail tool (25) is connected to the toothed pulley (4) through the conical tension bushing (29), and the end plug tail tool (25) passes through the toothed pulley (4). The toothed pulley (4) drives the end plug tail tool (25) to rotate.

2. The welding chamber for fuel rods and end plugs according to claim 1, characterized in that: A position sensor (17) is also installed on the tungsten electrode adjustment device (9).

3. A welding chamber for fuel rods and end plugs according to claim 1, characterized in that: The clamping mechanism (2) has an indexing plate (21) installed on its inner side. The toothed pulley (4) drives the rotating shaft (22) to rotate, which in turn drives the clamping mechanism (2) and the indexing plate (21) to rotate. The rotation angle is determined by the indexing plate (21).

4. A welding chamber for fuel rods and end plugs according to claim 1, characterized in that: Between the clamping mechanism (2) and the toothed pulley (4), there is a rotating shaft fixing device (3), through which the rotating shaft (22) passes; the rotating shaft fixing device (3) is installed on the rotating shaft fixing support device (1).

5. A welding chamber for fuel rods and end plugs according to claim 1, characterized in that: On the right side of the cavity shell (13), symmetrically arranged with respect to the left side of the cavity shell (13), the end plug tail tool (25) replaces the rotating shaft (22).

6. A welding chamber for fuel rods and end plugs according to claim 1, characterized in that: Since the carbon brush (11) is in contact with the conductive device (10), and the conductive device (10) is in contact with the end plug tail tool (25), a stable current is provided to the end plug tail tool (25). The end plug tail tool (25) is used as the negative electrode for welding, while the tungsten electrode at the lower end of the welding torch (8) is used as the positive electrode for welding.

7. A welding chamber for fuel rods and end plugs according to claim 1, characterized in that: At the right end of the cladding tube (23), a gas balancing device (27) is installed via a bracket (28). Inert gas is introduced into the gas balancing device (27), and the inert gas is discharged through the vent (26), thereby forming gas protection for the welding position.

8. A welding chamber for fuel rods and end plugs according to claim 1, characterized in that: The outer shell (13) of the cavity is equipped with a viewing window (6). There are multiple viewing windows (6). An automatic weld monitoring device (14) is installed at one of the viewing windows (6).

9. A welding chamber for fuel rods and end plugs according to claim 1, characterized in that: The rotating shaft fixing support device (1) and the cavity shell (13) are installed on the base plate (15).

10. A welding chamber for fuel rods and end plugs according to claim 1, characterized in that: A gas exchange device (12) is installed on the outer shell (13) of the cavity, and gas exchange between the inside and outside of the outer shell (1) is carried out through the gas exchange device (12).

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