Self-locking device for the transfer of fuel assemblies in nuclear power plants

Abstract

The utility model discloses a nuclear power station fuel assembly transfer's self -locking device, including rotation push push formula structure, and rotation push push formula structure includes support sleeve, power mechanism and ratchet sleeve, power mechanism and ratchet sleeve are respectively movably arranged in the first end and the second end of support sleeve, the periphery of ratchet sleeve is equipped with ratchet slot, and the second end of support sleeve is equipped with the guide pin of inserting ratchet slot, is equipped with work cycle in ratchet slot, power mechanism can go back and forth movement along the axial direction of support sleeve, and drive ratchet sleeve relative guide pin axial movement, and guide pin passes work cycle's work position in ratchet slot in proper order, drives ratchet sleeve relative support sleeve and carries out the circumferential rotation. The utility model discloses through the cooperation of ratchet sleeve and guide pin in support sleeve, and ratchet sleeve can carry out axial movement and circumferential rotation, realizes the multiple working conditions of push push formula structure, solves the problem of multiple position stay in single application / pull pressure process.

Description

Technical Field

[0001] This utility model relates to the field of self-locking equipment technology for nuclear power plants, and in particular to a self-locking device for transferring fuel assemblies in a nuclear power plant. Background Technology

[0002] The common push-push structure is a press-type elastic structure, such as ballpoint pens and memory card slots. By applying external force (such as pressing), the structure has two working states. After one press, the structure automatically locks. After another press, the structure automatically resets and locks. By continuously switching between the locked and reset locking states, the corresponding functions are achieved, such as the extension and retraction of the pen refill.

[0003] If the end effector of the push-type structure is in the initial position, a single press will cause the end effector to extend to its limit position and then retract to the working position, maintaining a stable lock. A second press will similarly cause the end effector to extend to its limit position and then retract to the initial position, maintaining a stable reset lock. During these two presses, there are only two locking positions; the limit position cannot lock. For devices with multiple operating states, the above-described push-type structure cannot meet the requirements, such as the operation of nuclear fuel assemblies, which involves multiple operating states. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a self-locking device for transferring fuel assemblies in nuclear power plants that can switch between multiple working states.

[0005] The technical solution adopted by this utility model to solve its technical problem is: to provide a self-locking device for transferring fuel assemblies in a nuclear power plant, including a rotary push-type structure, wherein the rotary push-type structure includes a support sleeve, a power mechanism and a ratchet slide sleeve; the support sleeve has a first end and a second end opposite to each other, and the power mechanism and the ratchet slide sleeve are respectively movably arranged in the first end and the second end;

[0006] The ratchet sleeve has a ratchet groove in its circumferential direction; the second end of the support sleeve has a guide pin inserted into the ratchet groove; the ratchet groove has at least one working cycle, and the working cycle includes five working positions arranged sequentially in the circumferential direction.

[0007] The power mechanism can move back and forth along the axial direction of the support sleeve, driving the ratchet slide sleeve to move axially relative to the guide pin. At the same time, the guide pin passes through the working position of the working cycle along the ratchet groove, driving the ratchet slide sleeve to rotate circumferentially relative to the support sleeve.

[0008] Preferably, the rotary push-type structure further includes a connecting seat and a core rod; the connecting seat is disposed inside the support sleeve and between the power mechanism and the ratchet slide sleeve, and can move back and forth along the axial direction of the support sleeve; the core rod is connected between the connecting seat and the ratchet slide sleeve, is fixed relative to the ratchet slide sleeve and rotatable relative to the connecting seat.

[0009] Preferably, the rotary push-type structure further includes a reset elastic element, which is disposed inside the support sleeve and abuts against the connecting seat, for driving the connecting seat to move axially and then reset.

[0010] Preferably, the connecting seat is fixed to the power mechanism and forms an integral part with the power mechanism; or, the connecting seat is spaced apart from the power mechanism; the cylinder wall of the support sleeve is provided with at least one connecting hole extending along the axial direction of the support sleeve, and at least one end of the connecting seat is fitted into the connecting hole, thereby supporting it in the support sleeve.

[0011] Preferably, the rotary push-type structure further includes an emergency handle, which is connected to the connecting seat and extends out of the support sleeve.

[0012] Preferably, the ratchet groove includes a plurality of first ratchet teeth and a plurality of second ratchet teeth arranged vertically opposite each other;

[0013] A first ratchet groove is formed between two adjacent first ratchet teeth, and a second ratchet groove is formed between two adjacent second ratchet teeth; the five working positions of the work cycle are staggered in the first ratchet groove and the second ratchet groove.

[0014] Preferably, the first ratchet includes a first straight surface and a first inclined surface facing away from each other, and a first tooth tip is formed at the junction of the first straight surface and the first inclined surface; the second ratchet includes a second straight surface and a second inclined surface facing away from each other, and a second tooth tip is formed at the junction of the second straight surface and the second inclined surface.

[0015] The first tip of the first ratchet faces the second slope of the second ratchet, and the second tip of the second ratchet faces the first slope of the first ratchet.

[0016] Preferably, of the five working positions, the first and fifth working positions and the third working position are respectively located in the second ratchet groove, and the second and fourth working positions are respectively located in the first ratchet groove.

[0017] Preferably, the second ratchet groove corresponding to the first and last working positions has a channel at the bottom extending along the axial direction of the ratchet sleeve, so that the working position is transferred to the bottom of the channel.

[0018] Preferably, the self-locking device for transferring nuclear power plant fuel assemblies further includes a fuel assembly gripping mechanism. The rotary push-type structure is connected above the fuel assembly gripping mechanism. The rotary push-type structure drives the fuel assembly gripping mechanism to grip and release fuel assemblies and achieve the self-locking function through the axial movement and circumferential rotation of the ratchet slide sleeve.

[0019] The beneficial effects of this utility model are as follows: through the cooperation between the ratchet slide sleeve and the guide pin inside the support sleeve, the ratchet slide sleeve can move axially and rotate circumferentially under the linkage of the power mechanism, realizing multiple working states of the push-push structure and solving the problem of multiple positions stopping during a single application / tension and pressure process. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0021] Figure 1 This is a three-dimensional structural diagram of a rotating push-type structure according to an embodiment of the present invention;

[0022] Figure 2 yes Figure 1 A schematic diagram of the axial cross-sectional structure of the rotary push-type structure shown.

[0023] Figure 3 yes Figure 1 A schematic diagram of the internal structure of the support sleeve of the rotary push-type structure shown.

[0024] Figure 4 yes Figure 1 A three-dimensional structural diagram of the ratchet sliding sleeve in the rotary push-type structure shown.

[0025] Figure 5 yes Figure 4 The front view of the ratchet sleeve shown;

[0026] Figure 6 yes Figure 5 The diagram shows the distribution of working positions in the ratchet sleeve.

[0027] Figure 7 This is a schematic diagram of the structure of a self-locking device for transferring nuclear power plant fuel assemblies above the fuel assembly, according to an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of the self-locking process of the fuel assembly transfer self-locking device in a nuclear power plant according to an embodiment of the present invention;

[0029] Figure 9 This is a schematic diagram of the process of unlocking fuel assemblies by a self-locking device for transferring fuel assemblies in a nuclear power plant, according to an embodiment of this utility model. Detailed Implementation

[0030] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0031] The present invention relates to a self-locking device for transferring fuel assemblies in nuclear power plants, which may include a rotary-push structure. The rotary-push structure can be applied to the gripping, releasing, and self-locking of fuel assemblies in nuclear power plants.

[0032] like Figures 1-3 As shown, a rotary push-type structure according to an embodiment of the present invention includes a support sleeve 10, a power mechanism 20, and a ratchet slide sleeve 30. The support sleeve 10 has a first end and a second end opposite to each other, and the power mechanism 20 and the ratchet slide sleeve 30 are respectively movably disposed in the first end and the second end; the power mechanism 20 can move back and forth along the axial direction of the support sleeve 10, driving the ratchet slide sleeve 30 to move back and forth along the axial direction of the support sleeve 10 and rotate circumferentially.

[0033] The second end of the support sleeve 10 has a protruding guide pin 40, and the ratchet sleeve 30 has a ratchet groove 50 in the circumferential direction, into which the guide pin 40 is inserted. When the power mechanism 20 moves back and forth along the axial direction of the support sleeve 10, it drives the ratchet sleeve 30 to move axially relative to the guide pin 40. At the same time, the guide pin 40 moves circumferentially along the ratchet groove 50. After passing through the working position of the working cycle, the ratchet sleeve 30 is driven to rotate circumferentially relative to the support sleeve 10.

[0034] Specifically, the first end of the support sleeve 10 is an open end, and the power mechanism 20 can enter and exit the first end from above to drive the axial movement of the ratchet sleeve 30. Alternatively, a portion of the power mechanism 20 extends into and is positioned within the first end, and can move axially along the support sleeve 10, thereby driving the axial movement of the ratchet sleeve 30. The power mechanism 20 may include a power block, which moves back and forth axially along the support sleeve 10 under the drive of the power drive assembly, and the power mechanism 20 drives the ratchet sleeve 30 through the power block.

[0035] The second end of the support sleeve 10 is an open end, and the ratchet sleeve 30 fits inside the second end and can move axially along the support sleeve 10; the end of the ratchet sleeve 30 away from the power mechanism 20 is exposed outside the support sleeve 10. A guide pin 40 is disposed inside the second end of the support sleeve 10, and its length extending beyond the second end of the support sleeve 10 during axial movement can be determined according to the stroke of the actuator connected to the ratchet sleeve 30. For example, in... Figure 3 In the embodiment shown, the guide pin 40 is located inside the port of the second end of the support sleeve 10, and the ratchet groove 50 is located at the upper end of the ratchet slide sleeve 30 facing the power mechanism 20. Therefore, when the guide pin 40 and the ratchet slide sleeve 30 are engaged, the lower end of the ratchet slide sleeve 30 extends out of the second end of the support sleeve 10.

[0036] Furthermore, the second end of the support sleeve 10 is also provided with a mounting flange 11, and the ratchet sleeve 30 extends out of the second end of the support sleeve 10 through the center hole of the mounting flange 11. The mounting flange 11 can support the ratchet sleeve 30 and is also used for installation and positioning in rotary push-type structure applications.

[0037] The ratchet sleeve 30 has at least one working cycle within the ratchet groove 50. The working cycle includes five working positions arranged sequentially around the circumference of the ratchet sleeve 30. When the ratchet sleeve 30 moves axially relative to the guide pin 40, it drives the guide pin 40 to pass sequentially through the working positions of the working cycle along the ratchet groove 50, while simultaneously driving the ratchet sleeve 30 to rotate circumferentially along the support sleeve 10.

[0038] To ensure that the ratchet sleeve 30 also rotates circumferentially relative to the guide pin 40 during axial movement, the working positions of the ratchet groove 50 are provided with guide surfaces. During axial movement of the ratchet sleeve 30, the guide pin 40, guided by the guide surfaces, moves from one working position to an adjacent working position, causing the ratchet sleeve 30 to rotate circumferentially.

[0039] Combination Figures 3-5 With the end of the ratchet sleeve 30 facing the power mechanism 20 as the upper end and the end facing away from the power mechanism 20 as the lower end, the ratchet groove 50 includes several first ratchet teeth 51 and several second ratchet teeth 52 that are vertically opposite each other. A first ratchet groove 510 is formed between two adjacent first ratchet teeth 51, and a second ratchet groove 520 is formed between two adjacent second ratchet teeth 52; the five working positions of the working cycle are staggered in the first ratchet groove 510 and the second ratchet groove 520.

[0040] In the ratchet groove 50, the first ratchet 51 and the second ratchet 52 are offset, such that the first ratchet 51 corresponds to the second ratchet groove 520, and the second ratchet 52 corresponds to the first ratchet groove 510.

[0041] In one embodiment, the first ratchet 51 includes a first straight surface 511 and a first inclined surface 512 facing away from each other, with a first tooth tip formed at the junction of the first straight surface 511 and the first inclined surface 512. The second ratchet 52 includes a second straight surface 521 and a second inclined surface 522 facing away from each other, with a second tooth tip formed at the junction of the second straight surface 521 and the second inclined surface 522. The first inclined surface 512 and the second inclined surface 522 have opposite inclination directions, and their extensions intersect. The first tooth tip of the first ratchet 51 faces the second inclined surface 522 of the second ratchet 52, and the second tooth tip of the second ratchet 52 faces the first inclined surface 512 of the first ratchet 51.

[0042] The first straight surface 511 and the first inclined surface 512, as well as the second straight surface 521 and the second inclined surface 522, all serve a guiding function. When the guide pin 40 is in the first ratchet groove 510, the axial movement of the ratchet sleeve 30 drives the guide pin 40 to fall along the first straight surface 511, abut against the second inclined surface 522, and enter the second ratchet groove 520 along the second inclined surface 522. When the guide pin 40 is in the second ratchet groove 520, the axial movement of the ratchet sleeve 30 drives the guide pin 40 to move upward along the second straight surface 521, abut against the first inclined surface 512, and enter the first ratchet groove 510 along the first inclined surface 512.

[0043] refer to Figures 4-6 The five workstations in the first work cycle are designated as workstation 1, workstation 2, workstation 3, workstation 4, and workstation 5. Figure 6 The five working positions are respectively represented by I, II, III, IV, and V. In this embodiment, the first and last working positions (i.e., the first working position I and the fifth working position V) and the third working position III are respectively located in the second ratchet groove 520, and the second working position II and the fourth working position IV are respectively located in the first ratchet groove 510. When the ratchet sleeve 30 moves axially, the guide pin 40 can move upward from the first working position I to the second working position II, then downward to the third working position III, then upward to the fourth working position IV, and finally downward to the fifth working position V, thus completing one working cycle.

[0044] When the rotary push-type structure of this utility model is applied, the guide pin 40 is in different working positions corresponding to different working states. The first working position I and the fifth working position V can be in the same working state, while the second working position II to the fourth working position IV can be in different working states respectively, so that four working states can be achieved in one working cycle.

[0045] In a preferred embodiment, a second ratchet groove 520 corresponding to the first and last working positions (first working position I and fifth working position V) has a channel 53 at its bottom extending downward along the axial direction of the ratchet sleeve 30, allowing the working position to move to the bottom of the channel 53. A lower limit can be set in the channel 53 as needed to restrict the position of the working position.

[0046] Preferably, there are two or more working cycles within the ratchet groove 50. In an embodiment with two working cycles, the ratchet groove 50 is opened along the entire circumference of the ratchet sleeve 30, and the two working cycles are symmetrically distributed within the ratchet groove 50. The first and last working positions of the two working cycles are shared, so that after the guide pin 40 reaches the fifth working position V of the first working cycle, it is simultaneously at the first working position I of the second working cycle. Correspondingly, there are two guide pins 40, positioned on opposite sides of the inner circumference of the support sleeve 10 corresponding to the two working cycles.

[0047] In an embodiment with four working cycles, the ratchet groove 50 is formed along the entire circumference of the ratchet sleeve 30. The four working cycles are arranged circumferentially along the ratchet groove 50, and the first and last working positions of the four working cycles are shared. The first working position I of one working cycle is the fifth working position V of the previous working cycle, and its fifth working position V is the first working position I of the next working cycle. Two or four guide pins 40 can be provided. When one guide pin 40 moves from one working cycle to an adjacent working cycle, the ratchet sleeve 30 rotates 90°; when one guide pin 40 completes four working cycles, the ratchet sleeve 30 rotates one full rotation, i.e., 360°.

[0048] Furthermore, combined Figures 1-3 The rotary push-type structure also includes a connecting seat 60 and a core rod 70. The connecting seat 60 is disposed inside the support sleeve 10 and between the power mechanism 20 and the ratchet sleeve 30, and can move back and forth along the axial direction of the support sleeve 10. The core rod 70 is connected between the connecting seat 60 and the ratchet sleeve 30, and is fixed relative to the ratchet sleeve 30 but rotatable relative to the connecting seat 60. Preferably, the ratchet sleeve 30 is sleeved on the end of the core rod 70 away from the connecting seat 60 and is fixedly connected to the core rod 70. When the ratchet sleeve 30 rotates circumferentially relative to the support sleeve 10, it also drives the core rod 70 to rotate relative to the connecting seat 60.

[0049] In one embodiment, the connecting seat 60 can be fixed to the power mechanism 20 and form an integral part with the power mechanism 20. Specifically, the connecting seat 60 can be connected to the end of the power mechanism 20 that passes through the support sleeve 10. When the power mechanism 20 is started and moves back and forth along the axial direction of the support sleeve 10, the ratchet slide sleeve 30 is driven to move through the connecting seat 60 and the core rod 70.

[0050] In another embodiment, the connecting seat 60 and the power mechanism 20 are spaced apart. After the power mechanism 20 is started, it moves back and forth along the axial direction of the support sleeve 10, pressing against the connecting seat 60 and driving the connecting seat 60 and the core rod 70 to move axially, thereby driving the ratchet slide sleeve 30 to move. Corresponding to the arrangement of the connecting seat 60 in this embodiment, the cylinder wall of the support sleeve 10 is provided with at least one connecting hole 12 extending along the axial direction of the support sleeve 10, and at least one end of the connecting seat 60 is fitted into the connecting hole 12, thereby being supported in the support sleeve 10.

[0051] The rotary push-type structure also includes a reset elastic element 80, which is disposed inside the support sleeve 10 and abuts against the connecting seat 60. It is used to drive the connecting seat 60 to move axially and then reset. Specifically, when the power mechanism 20 moves downward, it compresses the reset elastic element 80 and drives the connecting seat 60 and the core rod 70 downward. When the power mechanism 20 moves upward to reset, the reset elastic element 80 extends and returns to its original position under its own restoring force, simultaneously lifting the connecting seat 60 and driving the connecting seat 60 and the core rod 70 to move upward and reset. The core rod 70 also drives the ratchet sleeve 30 to move upward and rotate.

[0052] The reset elastic element 80 can be, but is not limited to, a spring. When the reset elastic element 80 is a spring, it is limited within the support sleeve 10 and sleeved on the outer periphery of the core rod 70, and can also extend to sleeved on the outer periphery of the ratchet slide sleeve 30.

[0053] Furthermore, as needed, the rotary push-type structure may also include at least one emergency handle 90, which is connected to the connecting seat 60 and extends out of the support sleeve 10 for easy manual operation. In the event of failure of the reset elastic element 80 or failure of the power mechanism 20, the emergency handle 90 can be manually operated to reset the connecting seat 60 by moving it upward.

[0054] The emergency handle 90 is located outside the support sleeve 10, and one end of it can be fixedly connected to the connecting seat 60 through the connecting hole 12. Alternatively, one end of the emergency handle 90 is engaged with the connecting seat 60 at the end of the connecting hole 12.

[0055] refer to Figure 7 This utility model discloses a self-locking device for transferring fuel assemblies in a nuclear power plant, comprising a fuel assembly gripping mechanism 100 and the aforementioned rotary-push structure, which is connected above the fuel assembly gripping mechanism 100. The rotary-push structure, through the axial movement and circumferential rotation of the ratchet sleeve 30, drives the fuel assembly gripping mechanism 100 to grip and release fuel assemblies 200 (shown as the upper tube seat of the fuel assembly) and achieves a self-locking function.

[0056] The top of the gripper mechanism of the fuel assembly gripping mechanism 100 is fixedly connected to the bottom of the ratchet sleeve 30, and the end of the core rod 70 can extend out of the bottom of the ratchet sleeve 30, and is provided with a mating structure for fixed connection with the top of the gripper mechanism.

[0057] Combination Figures 6-8 Corresponding to the fuel assembly gripping mechanism 100, in one working cycle of the rotary push-type structure, the initial position of the guide pin 40 is set as the first working position I (or the fifth working position V).

[0058] When the self-locking device for transferring nuclear power plant fuel assemblies is in operation, it is lifted above the fuel assembly 200, at which point the guide pin 40 of the rotating push-type structure is in the first working position I within the ratchet groove 50. The self-locking device is then lowered until the grippers of the fuel assembly gripping mechanism 100 extend into the top of the fuel assembly 200, as... Figure 8 As shown in (a). The power mechanism 20 drives the ratchet sleeve 30 to move axially and rotate circumferentially, causing the guide pin 40 to reach the second working position II. Simultaneously, the fuel assembly gripping mechanism 100 descends, causing the gripper to reach the gripping position, as shown in (a). Figure 8As shown in (a)-(b). The power mechanism 20 continues to drive the ratchet sleeve 30 to move axially and rotate circumferentially, causing the guide pin 40 to reach the third working position III. At this time, the fuel assembly gripping mechanism 100 rises, causing the gripper to rise to the locking position of the fuel assembly 200, achieving self-locking. Figure 8 As shown in (b)-(c). Then, the self-locking device for transferring nuclear power plant fuel assemblies and fuel assembly 200 can be lifted together.

[0059] Combination Figure 6 , Figure 7 and Figure 9 When the self-locking device for transferring fuel assemblies in a nuclear power plant releases fuel assembly 200, the power mechanism 20 drives the ratchet sleeve 30 to move axially and rotate circumferentially, causing the guide pin 40 to move from the third working position III to the fourth working position IV. At this time, the fuel assembly gripping mechanism 100 descends, causing the gripper to descend from the locked position, thus unlocking the assembly. Figure 9 As shown in (a)-(b). The ratchet sleeve 30 continues to move axially and rotate circumferentially via the power mechanism 20, causing the guide pin 40 to move from the fourth working position IV to the fifth working position V. At this time, the fuel assembly gripping mechanism 100 rises, causing the gripper to rise and disengage from the fuel assembly 200, as shown in (a)-(b). Figure 9 As shown in (b)-(c). Figure 9 As shown in (d), the self-locking device for transferring nuclear power plant fuel assemblies is lifted and detached from fuel assembly 200.

[0060] The rotary push-type structure of this utility model can be connected to a remote control device to realize remote operation. Furthermore, it can realize the self-locking and unlocking between the fuel assembly gripping mechanism 100 and the fuel assembly 200, thereby realizing the transfer of the fuel assembly 200, etc.

[0061] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A self-locking device for transferring fuel assemblies in a nuclear power plant, characterized in that, The invention includes a rotary push-type structure, which comprises a support sleeve, a power mechanism, and a ratchet slide sleeve; the support sleeve has a first end and a second end opposite to each other, and the power mechanism and the ratchet slide sleeve are respectively movably disposed within the first end and the second end; The ratchet sleeve has a ratchet groove in its circumferential direction, and the second end of the support sleeve has a guide pin that is inserted into the ratchet groove; the ratchet groove has at least one working cycle, and the working cycle includes five working positions arranged sequentially in the circumferential direction. The power mechanism can move back and forth along the axial direction of the support sleeve, driving the ratchet slide sleeve to move axially relative to the guide pin. At the same time, the guide pin passes through the working position of the working cycle along the ratchet groove, driving the ratchet slide sleeve to rotate circumferentially relative to the support sleeve.

2. The self-locking device for transferring fuel assemblies in a nuclear power plant according to claim 1, characterized in that, The rotary push-type structure also includes a connecting seat and a core rod; The connecting seat is disposed inside the support sleeve and between the power mechanism and the ratchet slide sleeve, and can move back and forth along the axial direction of the support sleeve; The core rod is connected between the connecting seat and the ratchet sleeve, and is fixed relative to the ratchet sleeve but rotatable relative to the connecting seat.

3. The self-locking device for transferring fuel assemblies in a nuclear power plant according to claim 2, characterized in that, The rotary push-type structure also includes a reset elastic element, which is disposed in the support sleeve and abuts against the connecting seat, and is used to drive the connecting seat to move axially and then reset.

4. The self-locking device for transferring fuel assemblies in a nuclear power plant according to claim 2, characterized in that, The connecting seat is fixed to the power mechanism and forms an integral part with the power mechanism; or, the connecting seat is spaced apart from the power mechanism; the cylinder wall of the support sleeve is provided with at least one connecting hole extending along the axial direction of the support sleeve, and at least one end of the connecting seat is fitted into the connecting hole, thereby supporting it in the support sleeve.

5. The self-locking device for transferring fuel assemblies in a nuclear power plant according to claim 4, characterized in that, The rotary push-type structure also includes an emergency handle, which is connected to the connecting seat and extends out of the support sleeve.

6. The self-locking device for transferring fuel assemblies in a nuclear power plant according to any one of claims 1-5, characterized in that, The ratchet groove includes several first ratchet teeth and several second ratchet teeth that are positioned opposite each other. A first ratchet groove is formed between two adjacent first ratchet teeth, and a second ratchet groove is formed between two adjacent second ratchet teeth; the five working positions of the work cycle are staggered in the first ratchet groove and the second ratchet groove.

7. The self-locking device for transferring fuel assemblies in a nuclear power plant according to claim 6, characterized in that, The first ratchet includes a first straight surface and a first inclined surface facing away from each other, and a first tooth tip is formed at the junction of the first straight surface and the first inclined surface; the second ratchet includes a second straight surface and a second inclined surface facing away from each other, and a second tooth tip is formed at the junction of the second straight surface and the second inclined surface. The first tip of the first ratchet faces the second slope of the second ratchet, and the second tip of the second ratchet faces the first slope of the first ratchet.

8. The self-locking device for transferring fuel assemblies in a nuclear power plant according to claim 7, characterized in that, Of the five working positions, the first and fifth working positions and the third working position are respectively located in the second ratchet groove, and the second and fourth working positions are respectively located in the first ratchet groove.

9. The self-locking device for transferring fuel assemblies in a nuclear power plant according to claim 8, characterized in that, The second ratchet groove corresponding to the first and last working positions has a channel at the bottom extending along the axial direction of the ratchet sleeve, so that the working position is transferred to the bottom of the channel.

10. The self-locking device for transferring fuel assemblies in a nuclear power plant according to any one of claims 1-5, characterized in that, The self-locking device for transferring fuel assemblies in the nuclear power plant also includes a fuel assembly gripping mechanism. The rotary push-type structure is connected above the fuel assembly gripping mechanism. The rotary push-type structure drives the fuel assembly gripping mechanism to grip and release fuel assemblies and achieve the self-locking function through the axial movement and circumferential rotation of the ratchet sliding sleeve.

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