A nuclear fuel guide tube expansion device

Abstract

The present application provides a kind of nuclear fuel conduit expansion joint device, comprising: the outer conduit and inner conduit are arranged between multiple expansion joint petals, the inner side wall of expansion joint petal has protruding part for abutting with outer conduit.The expansion joint ring is arranged outside multiple expansion joint petals.The inner diameter of expansion joint ring is larger near one end of connecting pipe, and the inner diameter of the other end is smaller.The thickness of expansion joint petal is smaller near one end of connecting pipe, and larger away from one end of connecting pipe.When transmission assembly drives expansion joint ring to move along the outside of multiple expansion joint petals away from connecting pipe, expansion joint ring abuts with the outer side wall of expansion joint petal, so that multiple expansion joint petals are close to each other away from the end of connecting pipe, and then the abutting force of protruding part and outer conduit increases, and plastic deformation occurs in outer conduit and inner conduit.Thereby, outer conduit and inner conduit are expanded and fixed.This way of applying pressure from the outside to produce plastic deformation, outer and inner conduit are not easy to crack, and the yield after expansion is higher.

Description

Technical Field

[0001] This invention generally relates to the field of nuclear fuel skeleton expansion technology, and specifically to a nuclear fuel conduit expansion device. Background Technology

[0002] Existing nuclear fuel skeleton assemblies include grid assemblies, which have multiple square holes. In actual operation, some of these square holes need to be selected first, and conduits need to be installed inside them. These conduits include inner and outer conduits. They can be pre-jointed and fixed together before being welded to the grid assembly. Alternatively, the outer conduit can be welded to the grid assembly, and the inner conduit placed inside the outer conduit, with the portions extending out of the grid assembly then joined together.

[0003] Existing expansion joint processes include:

[0004] Insert the inner catheter into the outer catheter; insert the thinner end of the mandrel (thicker at one end and thinner at the other) into the expansion valve; insert the mandrel and expansion valve into the inner catheter; continue inserting the mandrel into the expansion valve, with the thicker end entering the expansion valve, causing the expansion valve to open and abut against the inner wall of the inner catheter, causing plastic deformation of the inner and outer catheters to form an expansion sac.

[0005] It is evident that the existing expansion joint process involves expanding from the inside of the tube, resulting in plastic deformation and an expansion bulge protruding outwards. This expansion joint method is prone to causing cracks in the outer or inner conduit during the expansion process, leading to damage and a low yield rate after expansion jointing. Summary of the Invention

[0006] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a nuclear fuel conduit expansion device.

[0007] This invention provides a nuclear fuel conduit expansion device for expanding an outer conduit and an inner conduit, comprising:

[0008] A connecting tube and multiple expansion valves; the multiple expansion valves are connected to the same end of the connecting tube and are parallel to each other in their natural state; the inner sidewall of the end of each expansion valve away from the connecting tube has a protrusion; the thickness of each expansion valve gradually decreases from the end away from the connecting tube to the end near the connecting tube; an outer conduit is disposed within the connecting tube and the multiple expansion valves, and an inner conduit is disposed within the outer conduit;

[0009] An expansion ring is sleeved on the outside of the plurality of expansion flaps; the inner diameter of the expansion ring gradually decreases from the end away from the connecting pipe to the end closer to the connecting pipe.

[0010] When the multiple expansion flaps are in their natural state, the inner diameter of the expansion ring near the end of the connecting pipe is smaller than the distance between the ends of the two expansion flaps away from the connecting pipe along the second direction;

[0011] A transmission assembly is mounted on the connecting pipe and connected to the expansion ring. The transmission assembly is used to drive the expansion ring to move along a first direction, so that the inner sidewall of the expansion ring abuts against the outer sidewall of the plurality of expansion flaps, and so that the ends of the plurality of expansion flaps away from the connecting pipe move closer to each other.

[0012] When the ends of the multiple expansion joints that are away from the connecting tube approach each other, the contact force between the protrusion and the outer wall of the outer conduit increases, causing the outer conduit and the inner conduit to undergo plastic deformation and become fixed to each other.

[0013] According to the technical solution provided by the present invention, it also includes:

[0014] An abutment shaft assembly is installed inside the connecting pipe and is used to abut against the inner wall of the inner conduit when the contact force between the protrusion and the outer wall of the outer conduit increases, thereby supporting the inner conduit.

[0015] According to the technical solution provided by the present invention, the abutment shaft assembly includes:

[0016] A first abutting shaft and a second abutting shaft, wherein the first abutting shaft is located inside the connecting tube, and one end is fixedly connected to the connecting tube, and the other end is detachably connected to one end of the second abutting shaft;

[0017] The inner conduit is sleeved on the outside of the first abutment shaft and the second abutment shaft;

[0018] A first groove is formed on the outer side wall of the end where the first abutting shaft and the second abutting shaft are connected; a second groove is formed on the outer side wall of the end of the second abutting shaft near the first connecting shaft.

[0019] When the first abutting shaft and the second abutting shaft are connected, the first groove and the second groove form a smooth groove-shaped structure; the groove-shaped structure and the protrusion are positioned corresponding to each other and their shapes match.

[0020] According to the technical solution provided by the present invention, the end of the second abutment shaft away from the first abutment shaft extends out of the outer conduit and the inner conduit.

[0021] According to the technical solution provided by the present invention, the transmission assembly includes:

[0022] A first mounting plate is fixedly connected to the outer wall of the connecting pipe;

[0023] A first driving device is fixedly mounted on the first mounting plate, and its driving end is fixedly connected to the expansion ring; the moving direction of the driving end of the first driving device is parallel to the first direction, and it is used to drive the expansion ring to move along the first direction.

[0024] According to the technical solution provided by the present invention, the outer wall of the connecting pipe has a slide rail;

[0025] The transmission assembly includes:

[0026] The second mounting plate is fixedly connected to the outer wall of the connecting pipe;

[0027] The first transmission tube is sleeved on the outside of the connecting tube, and one end is fixedly connected to the expansion ring; the outer side wall of the first transmission tube has a first threaded portion, and the inner side wall has a sliding groove; the slide rail is disposed in the sliding groove, so that the first transmission tube can slide relative to the expansion ring in a first direction, drive the expansion ring to move in the first direction, and prevent the first transmission tube from rotating relative to the expansion ring.

[0028] The second transmission tube is sleeved on the outside of the first transmission tube, and one end is rotatably connected to the second mounting plate; the inner sidewall of the second transmission tube has a second threaded portion for engaging with the first threaded portion, and the outer sidewall has an engaging portion;

[0029] A drive assembly is mounted on the second mounting plate and engages with the meshing part to drive the second transmission tube to rotate;

[0030] When the second transmission tube rotates, the first transmission tube moves along the first direction through the interaction between the first threaded part and the second threaded part.

[0031] According to the technical solution provided by the present invention, the driving component includes:

[0032] The second drive device is fixedly mounted on the second mounting plate;

[0033] The gear is fixedly connected to the drive shaft of the second drive device and is used to mesh with the meshing part to drive the second transmission tube to rotate.

[0034] According to the technical solution provided by the present invention, the expansion ring includes:

[0035] A ring body, which is sleeved on the outside of the plurality of expansion joints;

[0036] The ball bearing is rotatably mounted on the inner wall of the ring body and is used to abut against the outer wall of the expansion joint to generate relative rolling.

[0037] The beneficial effects of this invention are as follows:

[0038] An outer and inner conduit are positioned between multiple expansion flaps, each with a protrusion on its inner wall for contact with the outer conduit. An expansion ring is fitted over the outer side of the expansion flaps. The inner diameter of the expansion ring is larger at the end closer to the connecting pipe and smaller at the other end. The thickness of the expansion flaps is smaller at the end closer to the connecting pipe and larger at the end further away. When the transmission assembly moves the expansion ring along the outer side of the expansion flaps away from the connecting pipe, the expansion ring abuts against the outer wall of the expansion flaps, bringing the ends of the expansion flaps away from the connecting pipe closer together. This increases the contact force between the protrusion and the outer conduit, causing plastic deformation in both the outer and inner conduits. This expansion joint fixes the outer and inner conduits together. This method of applying pressure from the outside to induce plastic deformation reduces the likelihood of cracks in the inner and outer conduits, resulting in a higher yield rate after expansion. Attached Figure Description

[0039] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0040] Figure 1 This is a schematic diagram of the structure of a nuclear fuel conduit expansion device in one embodiment;

[0041] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0042] Figure 3 This is a schematic diagram of the nuclear fuel conduit expansion device in another embodiment;

[0043] Figure 4 This is a schematic diagram of the structure of the first abutment shaft in another embodiment;

[0044] Wherein: 1. Outer conduit; 2. Inner conduit; 3. Expansion ring; 4. Connecting pipe; 5. Expansion flap; 6. Protrusion; 7. First abutment shaft; 8. Second abutment shaft; 9. First groove; 10. Second groove; 11. First mounting plate; 12. First drive device; 13. Slide rail; 14. Second mounting plate; 15. First transmission pipe; 16. Second transmission pipe; 17. Engaging part; 18. Second drive device; 19. Gear; 20. Ring body; 21. Ball bearing; 22. Conical part. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] Please refer to Figure 1 This invention provides a nuclear fuel conduit expansion device for expanding an outer conduit 1 and an inner conduit 2, comprising:

[0048] A connecting tube 4 and multiple expansion flaps 5; the multiple expansion flaps 5 are connected to the same end of the connecting tube 4 and are parallel to each other in their natural state; the inner wall of the end of the expansion flap 5 away from the connecting tube 4 has a protrusion 6; the thickness of the expansion flap 5 gradually decreases from the end away from the connecting tube 4 to the end close to the connecting tube 4; the outer conduit 1 is disposed within the connecting tube 4 and the multiple expansion flaps 5, and the inner conduit 2 is disposed within the outer conduit 1;

[0049] An expansion ring 3 is sleeved on the outside of the plurality of expansion flaps 5; the inner diameter of the expansion ring 3 gradually decreases from the end away from the connecting pipe 4 to the end closer to the connecting pipe 4.

[0050] When the multiple expansion flaps 5 are in their natural state, the inner diameter of the expansion ring 3 near the end of the connecting pipe 4 is smaller than the distance between the ends of the two expansion flaps 5 away from the connecting pipe 4 along the second direction.

[0051] A transmission assembly is mounted on the connecting pipe 4 and connected to the expansion ring 3. The transmission assembly is used to drive the expansion ring 3 to move along a first direction, so that the inner sidewall of the expansion ring 3 abuts against the outer sidewall of the plurality of expansion petals 5, and so that the ends of the plurality of expansion petals 5 away from the connecting pipe 4 move closer to each other.

[0052] When the ends of the multiple expansion flaps 5 that are away from the connecting tube 4 approach each other, the contact force between the protrusion 6 and the outer wall of the outer conduit 1 increases, causing the outer conduit 1 and the inner conduit 2 to undergo plastic deformation and become fixed to each other.

[0053] Specifically, multiple expansion joints 5 are integrally formed with the connecting pipe 4 and have deformation capability.

[0054] When the drive assembly moves the expansion ring 3 away from the connecting pipe 4 along the first direction, the inner diameter of the expansion ring 3 at the point where it abuts the expansion flap 5 gradually decreases, and the contact force between the expansion ring 3 and the outer wall of the expansion flap 5 gradually increases, causing the outer conduit 1 and the inner conduit 2 to undergo plastic deformation, ultimately achieving mutual fixation.

[0055] The drive assembly moves the expansion ring 3 closer to the connecting tube 4, and the multiple expansion flaps 5 return to their natural state. This method of applying pressure from the outside to induce plastic deformation makes the inner and outer conduits less prone to cracking, resulting in a higher yield rate after expansion.

[0056] Furthermore, it also includes:

[0057] An abutment shaft assembly is installed inside the connecting pipe 4 and is used to abut against the inner wall of the inner conduit 2 when the abutment force between the protrusion 6 and the outer wall of the outer conduit 1 increases, thereby supporting the inner conduit 2.

[0058] Specifically, refer to Figure 2 The abutment shaft assembly includes:

[0059] A first abutting shaft 7 and a second abutting shaft 8, wherein the first abutting shaft 7 is located inside the connecting tube 4, and one end is fixedly connected to the connecting tube 4, and the other end is detachably connected to one end of the second abutting shaft 8;

[0060] The inner conduit 2 is sleeved on the outside of the first abutment shaft 7 and the second abutment shaft 8;

[0061] A first groove 9 is provided on the outer side wall of the connection end of the first abutting shaft 7 and the second abutting shaft; a second groove 10 is provided on the outer side wall of the end of the second abutting shaft 8 near the first connecting shaft.

[0062] When the first abutting shaft 7 and the second abutting shaft 8 are connected, the first groove 9 and the second groove 10 form a smooth groove structure; the groove structure and the protrusion 6 are positioned corresponding to each other and their shapes match.

[0063] In some embodiments, an abutment shaft assembly is also installed inside the connecting tube 4 for abutting against the inner conduit 2. This method can prevent excessive deformation of the inner conduit 2 during the expansion process, which could cause the entire tube to be squeezed into an irregular shape.

[0064] In some embodiments, the abutment shaft assembly includes a first abutment shaft 7 and a second abutment shaft 8. Before expansion, the second abutment shaft 8 is installed on the first abutment shaft 7. After expansion, the second abutment shaft 8 is removed from the first abutment shaft 7, and the outer conduit 1 and inner conduit 2, which are fixed together, are then removed from the expansion valve 5.

[0065] When the first abutting shaft 7 and the second abutting shaft 8 are connected to each other, the first groove 9 and the second groove 10 are connected to each other to form a smooth groove structure. The inner sidewall of the inner guide tube 2 fits against the groove structure, and the groove structure plays a role in supporting the inner guide tube 2, thereby shaping the inner guide tube 2.

[0066] In some embodiments, the protrusions 6 are all arc-shaped with equal radii, and the first groove 9 and the second groove 10 have the same length. This shape ensures that the groove structure, after being disassembled into the first groove 9 and the second groove 10, will not jam with the deformed inner conduit 2.

[0067] In some implementations, reference Figure 4 The first abutment shaft 7 has a larger radius at one end for connecting to the connecting pipe 4, and a smaller radius at the other end, which is a free end. A tapered portion 22 is located between the two ends of the first abutment shaft 7 with different radii. During expansion connection, the tapered portion 22 abuts against the inner wall of the inner conduit 2.

[0068] After one expansion connection is completed, the first abutment shaft 7 moves to the end with the larger radius, and the end with the smaller radius can be removed from the inner conduit 2.

[0069] When multiple expansion joints are required, the first abutment shaft 7 can be fully inserted into the inner guide tube 2. After one expansion joint, the first abutment shaft 7 is moved to the end with the larger radius, and then expansion joints are performed again; this process can be repeated multiple times.

[0070] Furthermore, the end of the second abutment shaft 8 that is away from the first abutment shaft 7 extends out of the outer conduit 1 and the inner conduit 2.

[0071] In some embodiments, the second abutment shaft 8 extends out of the inner guide tube 2, allowing for easy control of detaching the second abutment shaft 8 from the first abutment shaft 7.

[0072] Furthermore, the transmission assembly includes:

[0073] The first mounting plate 11 is fixedly connected to the outer wall of the connecting pipe 4;

[0074] A first driving device 12 is fixedly mounted on the first mounting plate 11, and its driving end is fixedly connected to the expansion ring 3. The moving direction of the driving end of the first driving device 12 is parallel to the first direction, and it is used to drive the expansion ring 3 to move along the first direction.

[0075] Specifically, the first driving device 12 is a servo cylinder, and the extension and retraction direction of its driving end is parallel to the first direction.

[0076] In this embodiment, the driving device 12 is provided in three sets, with each of the three driving ends fixedly connected to three different positions of the expansion ring 3. This method can more stably support the expansion ring 3 and drive it to move along the first direction.

[0077] Further, refer to Figure 3 The outer wall of the connecting pipe 4 has a slide rail 13;

[0078] The transmission assembly includes:

[0079] The second mounting plate 14 is fixedly connected to the outer wall of the connecting pipe 4;

[0080] The first transmission tube 15 is sleeved on the outside of the connecting tube 4, and one end is fixedly connected to the expansion ring 3; the outer side wall of the first transmission tube 15 has a first threaded portion, and the inner side wall has a sliding groove; the slide rail is disposed in the sliding groove, so that the first transmission tube 15 can slide relative to the expansion ring 3 in a first direction, drive the expansion ring 3 to move in the first direction, and prevent the first transmission tube 15 from rotating relative to the expansion ring 3.

[0081] The second transmission tube 16 is sleeved on the outside of the first transmission tube 15, and one end is rotatably connected to the second mounting plate 14; the inner sidewall of the second transmission tube 16 has a second threaded portion for engaging with the first threaded portion, and the outer sidewall has an engaging portion 17.

[0082] A drive assembly is mounted on the second mounting plate 14 and engages with the meshing part 17 to drive the second transmission tube 16 to rotate.

[0083] When the second transmission tube 16 rotates, the first transmission tube 15 moves along the first direction through the interaction between the first threaded portion and the second threaded portion.

[0084] In some embodiments, the sliding groove on the inner side of the first transmission tube 15 cooperates with the slide rail 13 on the connecting tube 4 to ensure that the first transmission tube 15 can only slide relative to the connecting tube 5 in the first direction and cannot rotate relative to it.

[0085] When the second transmission tube 16 rotates, it engages with the first transmission tube 15 by thread, causing the first transmission tube 15 to move in the first direction, which in turn causes the expansion ring 3 to move in the first direction.

[0086] Specifically, because it uses a cylinder-driven method, a relatively long space is required along the first direction. This transmission method allows the nuclear fuel conduit expansion device in this embodiment to adapt to a smaller space.

[0087] Furthermore, the driving component includes:

[0088] The second drive device 18 is fixedly mounted on the second mounting plate 14;

[0089] Gear 19 is fixedly connected to the drive shaft of the second drive device 18 and is used to mesh with the meshing part 17 to drive the second transmission tube 16 to rotate.

[0090] Specifically, the drive device 18 is a motor. When the drive device 18 rotates forward, it engages with the gear 19 and the meshing part 17, causing the second transmission tube 16 to rotate in reverse, and causing the first transmission tube 15 and the expansion ring 3 to move forward in the first direction.

[0091] When the drive device 18 reverses, it engages with the gear 19 and the meshing part 17, driving the second transmission tube 16 to rotate forward, and driving the first transmission tube 15 and the expansion ring 3 to move in the opposite direction along the first direction.

[0092] Furthermore, the expansion ring 3 includes:

[0093] Ring body 20, which is sleeved on the outside of the plurality of expansion joints 5;

[0094] The ball bearing 21 is rotatably mounted on the inner wall of the ring body 20. The ball bearing 21 is used to abut against the outer wall of the expansion joint 5 to generate relative rolling.

[0095] In some embodiments, a ball groove is provided on the inner sidewall of the ring 20, and the ball 21 is rotatably installed in the ball groove. The friction force can be reduced by the ball 21 abutting against the expansion joint 5, which facilitates the expansion joint.

[0096] At least three non-collinear balls 21 abut against each other on the same expansion joint 5. This method can prevent the expansion joint 5 from deforming perpendicular to the first direction during the expansion process, thus avoiding irregular shapes on the outer conduit 1 and the inner conduit 2.

[0097] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to the specific combination of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. A nuclear fuel conduit expansion device, characterized in that, Used for expanding and connecting external catheter (1) and internal catheter (2), including: A connecting tube (4) and multiple expansion flaps (5); the multiple expansion flaps (5) are connected to the same end of the connecting tube (4) and are parallel to each other in their natural state; the inner wall of the expansion flap (5) away from the connecting tube (4) has a protrusion (6); the thickness of the expansion flap (5) gradually decreases from the end away from the connecting tube (4) to the end close to the connecting tube (4); the outer conduit (1) is disposed in the connecting tube (4) and the multiple expansion flaps (5), and the inner conduit (2) is disposed in the outer conduit (1); An expansion ring (3) is sleeved on the outside of the plurality of expansion flaps (5); the inner diameter of the expansion ring (3) gradually decreases from the end away from the connecting pipe (4) to the end close to the connecting pipe (4); When the multiple expansion flaps (5) are in their natural state, the inner diameter of the expansion ring (3) near the end of the connecting pipe (4) is smaller than the distance between the ends of the two expansion flaps (5) away from the connecting pipe (4) along the second direction; A transmission assembly is mounted on the connecting pipe (4) and connected to the expansion ring (3) for driving the expansion ring (3) to move along a first direction, so that the inner wall of the expansion ring (3) abuts against the outer wall of the plurality of expansion petals (5), and so that the ends of the plurality of expansion petals (5) away from the connecting pipe (4) move closer to each other. When the ends of the multiple expansion flaps (5) away from the connecting tube (4) approach each other, the contact force between the protrusion (6) and the outer wall of the outer conduit (1) increases, causing the outer conduit (1) and the inner conduit (2) to undergo plastic deformation and become fixed to each other; The abutting shaft assembly is installed inside the connecting pipe (4) and is used to abut against the inner wall of the inner conduit (2) when the abutting force between the protrusion (6) and the outer wall of the outer conduit (1) increases, thereby supporting the inner conduit (2). The abutment shaft assembly includes: The first abutting shaft (7) and the second abutting shaft (8) are located inside the connecting tube (4), with one end fixedly connected to the connecting tube (4) and the other end detachably connected to one end of the second abutting shaft (8). The inner conduit (2) is sleeved on the outside of the first abutment shaft (7) and the second abutment shaft (8); A first groove (9) is provided on the outer side wall of the end where the first abutting shaft (7) and the second abutting shaft (8) are connected; a second groove (10) is provided on the outer side wall of the end of the second abutting shaft (8) near the first abutting shaft (7). When the first abutting shaft (7) and the second abutting shaft (8) are connected, the first groove (9) and the second groove (10) form a smooth groove structure; the groove structure and the protrusion (6) are positioned corresponding to each other and their shapes match.

2. The nuclear fuel conduit expansion device according to claim 1, characterized in that, The end of the second abutment shaft (8) that is away from the first abutment shaft (7) extends out of the outer conduit (1) and the inner conduit (2).

3. The nuclear fuel conduit expansion device according to claim 1, characterized in that, The transmission assembly includes: The first mounting plate (11) is fixedly connected to the outer wall of the connecting pipe (4); The first driving device (12) is fixedly installed on the first mounting plate (11), and the driving end is fixedly connected to the expansion ring (3); the moving direction of the driving end of the first driving device (12) is parallel to the first direction, and is used to drive the expansion ring (3) to move along the first direction.

4. A nuclear fuel conduit expansion device according to claim 1, characterized in that, The outer wall of the connecting pipe (4) has a slide rail (13). The transmission assembly includes: The second mounting plate (14) is fixedly connected to the outer wall of the connecting pipe (4); The first transmission tube (15) is sleeved on the outside of the connecting tube (4) and one end is fixedly connected to the expansion ring (3); the outer side wall of the first transmission tube (15) has a first threaded portion and the inner side wall has a sliding groove; the slide rail is set in the sliding groove to allow the first transmission tube (15) to slide relative to the expansion ring (3) in a first direction, drive the expansion ring (3) to move in the first direction, and prevent the first transmission tube (15) from rotating relative to the expansion ring (3); The second transmission tube (16) is sleeved on the outside of the first transmission tube (15), and one end is rotatably connected to the second mounting plate (14); the inner wall of the second transmission tube (16) has a second threaded portion for engaging with the first threaded portion, and the outer wall has an engaging portion (17). A drive assembly is mounted on the second mounting plate (14) and engages with the meshing part (17) to drive the second transmission tube (16) to rotate. When the second transmission tube (16) rotates, the first transmission tube (15) is driven to move along the first direction through the interaction between the first threaded part and the second threaded part.

5. A nuclear fuel conduit expansion device according to claim 4, characterized in that, The driving component includes: The second drive device (18) is fixedly mounted on the second mounting plate (14); Gear (19), which is fixedly connected to the drive shaft of the second drive device (18), is used to mesh with the meshing part (17) and drive the second transmission tube (16) to rotate.

6. A nuclear fuel conduit expansion device according to claim 1, characterized in that, The expansion ring (3) includes: A ring (20) is sleeved on the outside of the plurality of expansion joints (5); The ball (21) is rotatably mounted on the inner wall of the ring (20) and is used to abut against the outer wall of the expansion joint (5) to generate relative rolling.

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