Parallel drive control rod drive mechanism for a reactor

Abstract

The present application relates to the technical field of reactor, and particularly provides a parallel transmission control rod drive mechanism for reactor, aiming at solving the problem of large axial size of the control rod drive mechanism of the existing reactor. To this end, the parallel transmission control rod drive mechanism comprises a three-level nested assembly, a first parallel transmission assembly and a second parallel transmission assembly, the three-level nested assembly comprises rotating members, transmission members and gripper drive rods whose projections on the longitudinal section at least partially coincide, and the rotating members are adaptively connected with the gripper drive rods; the first parallel transmission assembly is used for driving the movement of the gripper and the control rod assembly in the guide pipe; and the second parallel transmission assembly is used for driving the rotating members to rotate and realizing the opening and closing control of the gripper. The parallel transmission control rod drive mechanism utilizes the three-level nested assembly and the parallel transmission assembly, can effectively reduce the axial size of the control rod drive mechanism, and is beneficial to the miniaturization development of the reactor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of reactor technology, and particularly provides a parallel transmission control rod drive mechanism for a reactor. BACKGROUND

[0002] The control rod drive mechanism is a key device for realizing effective control of reactivity and safe operation of the reactor, and generally adopts the mode of lifting or inserting the control rod assembly to realize control of reactivity. In the shutdown accident condition, the control rod assembly is released, and the control rod assembly falls into the core under the action of gravity to realize emergency shutdown.

[0003] At present, the control rod drive mechanism generally adopts the modes of magnetic force lifting and motor driving. For example, the control rod drive mechanism of the commercial pressurized water reactor generally adopts step magnetic force lifting, the coil assembly (holding coil, transmission coil, lifting coil) is energized and de-energized by the circulating power controller according to the design program, and the step lifting or lowering of the control rod assembly is driven by the magnetic force and the hook claw on the driving rod. For another example, the control rod drive mechanism of the liquid metal reactor mainly adopts motor driving, for example, the lifting or lowering of the control rod assembly is driven by the motor driving and the gear and rack pair transmission.

[0004] However, the axial size of the above-mentioned drive mechanism is large during driving the control rod assembly to move, which increases the overall height of the reactor and seriously restricts the miniaturization development of the reactor. SUMMARY

[0005] The present application aims to solve the above technical problems, i.e., to solve the problem that the existing control rod has no self-locking function during use.

[0006] The present application provides a parallel transmission control rod drive mechanism for a small reactor, which is used for controlling the movement of a gripper and a control rod assembly in a guide tube, the gripper being used for grabbing or releasing the control rod assembly, wherein the parallel transmission control rod drive mechanism comprises:

[0007] a three-level nested assembly, the three-level nested assembly comprising a rotating member, a transmission member and a gripper driving rod, a vertical plane of a horizontal plane being a longitudinal section plane, projections of the rotating member, the transmission member and the gripper driving rod on the longitudinal section plane at least partially coincide, the rotating member and the gripper driving rod are adaptively connected, and the transmission member is arranged in a spaced manner with the gripper driving rod;

[0008] a first parallel transmission assembly arranged beside one side of the three-level nested assembly, one end of the first parallel transmission assembly being connected with the transmission member, and being used for driving the movement of the gripper and the control rod assembly in the guide tube;

[0009] A second parallel transmission assembly is arranged beside the third nested assembly, one end of the second parallel transmission assembly is connected with the rotating member for driving the rotating member to rotate and realizing the opening and closing control of the gripper.

[0010] In the preferred technical scheme of the parallel transmission control rod drive mechanism for small-sized reactors, the rotating member comprises a sleeve with an opening at the bottom, the inner wall of the sleeve is provided with a sliding rail groove, one end of the gripper driving rod passes through the opening and is connected with the sliding rail groove.

[0011] At least part of the transmission members pass through the opening and extend into the sleeve, and the transmission members in the sleeve are spaced apart from the inner wall of the sleeve by a predetermined distance.

[0012] In the preferred technical scheme of the parallel transmission control rod drive mechanism for small-sized reactors, the transmission member comprises a first gear and a rack meshing with the first gear.

[0013] The first gear is rotationally connected with the first parallel transmission assembly, and at least part of the rack is inserted into the rotating member, so that under the driving of the first parallel transmission assembly, one end of the rack moves in the rotating member in the axial direction of the guide pipe.

[0014] In the preferred technical scheme of the parallel transmission control rod drive mechanism for small-sized reactors, the first parallel transmission assembly comprises a first motor and a first gear pair.

[0015] The output shaft end of the first motor is connected with a first speed reducer, and the output shaft end of the first speed reducer is connected with the first gear pair.

[0016] The output shaft end of the first gear pair is connected with the first gear transmission.

[0017] The highest point of the first motor is arranged at a height lower than the height of the horizontal position where the rack is at the highest point.

[0018] In the preferred technical scheme of the parallel transmission control rod drive mechanism for small-sized reactors, the parallel transmission control rod drive mechanism further comprises a rod position measurement assembly arranged on the first gear pair to measure the displacement of the control rod assembly through the rotation angle measurement of the transmission gear in the first gear pair.

[0019] In the preferred technical scheme of the parallel transmission control rod drive mechanism for small-sized reactors, the second parallel transmission assembly comprises a second motor and a second gear pair.

[0020] The output shaft end of the second motor is connected with a second speed reducer, and the output shaft end of the second speed reducer is connected with the second gear pair;

[0021] The output shaft end of the second gear pair is connected with the rotating member;

[0022] The height of the highest point of the second motor is lower than the height of the highest point of the rack.

[0023] In the preferred technical solution of the parallel transmission control rod drive mechanism for the small reactor, the first motor and the second motor are all anti-10 7 Gy radiation dose anti-radiation motor.

[0024] In the preferred technical solution of the parallel transmission control rod drive mechanism for the small reactor, the parallel transmission control rod drive mechanism further comprises a counterweight, which is arranged on the gripper driving rod, the transmission member and the control rod assembly, wherein the counterweight is a heavy metal structural member with a density greater than that of the coolant in the guide tube, so that the total weight of the gripper driving rod, the transmission member, the gripper and the control rod assembly is greater than the buoyancy generated by the coolant.

[0025] In the preferred technical solution of the parallel transmission control rod drive mechanism for the small reactor, the parallel transmission control rod drive mechanism further comprises a shielding layer, which is arranged above the guide tube and covers the part of the three-level nested assembly exposed to the outside.

[0026] In the preferred technical solution of the parallel transmission control rod drive mechanism for the small reactor, the parallel transmission control rod drive mechanism further comprises a self-locking assembly, which is used to disconnect the control between the first parallel transmission assembly and the transmission member in an accident state, so as to realize the rapid falling and reverse self-locking of the control rod assembly.

[0027] In the case of using the above technical solution, the parallel transmission control rod drive mechanism of the present application has a first parallel transmission assembly and a second parallel transmission assembly beside the guide tube, wherein the first parallel transmission assembly is used to drive the gripper and the control rod assembly to move linearly in the vertical direction in the guide tube, and the second parallel transmission assembly is used to drive the rotating member to rotate and realize the opening and closing control of the gripper. At the same time, cooperating with the nesting form of the three-level nested assembly, the axial size of the control rod drive mechanism is effectively reduced, which is beneficial to the miniaturization development of the reactor. BRIEF DESCRIPTION OF DRAWINGS

[0028] The preferred embodiments of the present application will be described below with reference to the accompanying drawings, in which:

[0029] Figure 1 is a structural schematic view of a parallel drive control rod drive mechanism for a small reactor according to an exemplary embodiment;

[0030] Figure 2 is a structural schematic view of a driving member in a parallel drive control rod drive mechanism for a small reactor according to an exemplary embodiment.

[0031] BRIEF DESCRIPTION OF DRAWINGS

[0032] 1, three-stage nested assembly; 11, rotating member; 12, driving member; 13, gripper driving rod; 121, first gear; 122, rack;

[0033] 2, first parallel drive assembly; 21, first motor; 22, first gear pair; 23, first speed reducer;

[0034] 3, second parallel drive assembly; 31, second motor; 32, second gear pair; 33, second speed reducer;

[0035] 4, rod position measurement assembly; 5, shielding layer; 6, self-locking assembly; 10, guide tube; 20, gripper; 30, control rod assembly. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application.

[0037] The present application will be further illustrated below with reference to the accompanying drawings in conjunction with the embodiments.

[0038] As shown in Figure 1 , an exemplary embodiment of the present application provides a parallel drive control rod drive mechanism for a small reactor for controlling the movement of a gripper 20 and a control rod assembly 30 in a guide tube 10, wherein the gripper 20 is used to grab or release the control rod assembly 30. The parallel drive control rod drive mechanism for a small reactor includes a three-stage nested assembly 1, a first parallel drive assembly 2, and a second parallel drive assembly 3.

[0039] Referring to Figure 1 , the guide tube 10 is internally configured as a hollow structure, and the hollow structure is configured as a passage for the gripper 20 and the control rod assembly 30 to pass through.

[0040] Part of the three-level nested assembly 1 is located in the guide tube 10, specifically, the lower half of the three-level nested assembly 1 extends into the guide tube 10. Among them, the three-level nested assembly 1 extending into the guide tube 10 is arranged at a predetermined distance from the inner wall of the guide tube 10, and the predetermined distance is in the range of 0.5mm-2mm, so as to facilitate the movement of the three-level nested assembly 1 in the guide tube 10 along the vertical direction.

[0041] Referring to Figure 1 and in combination Figure 2 It is shown that the three-level nested assembly 1 includes a rotating part 11, a transmission part 12 and a gripper driving rod 13. With a vertical plane as a longitudinal section, the projections of the rotating part 11, the transmission part 12 and the gripper driving rod 13 on the longitudinal section at least partially coincide. In the vertical direction, the lower end of the rotating part 11 can be buckled on the top of the transmission part 12 and the top of the gripper driving rod 13. Among them, the rotating part 11 is internally configured with an accommodation space, and the bottom of the accommodation space has an open mouth. The top of the transmission part 12 passes through the open mouth and extends into the accommodation space, and the top of the transmission part 12 can move in the vertical direction in the accommodation space. Among them, the transmission part 12 can be connected with the gripper 20 or the control rod assembly 30, so that the movement of the transmission part 12 drives the movement of the control rod assembly 30 and the gripper 20.

[0042] The rotating part 11 is adaptively connected with the gripper driving rod 13, for example, the gripper driving rod 13 can slide along the axial direction of the rotating part 11, while the rotating part 11 can drive the gripper driving rod 13 to rotate along the radial direction. The gripper driving rod 13 is connected with the gripper 20. For example, the top of the gripper driving rod 13 is threadedly connected with the inside of the rotating part 11, so as to convert the rotation of the rotating part 11 into the vertical movement of the gripper driving rod 13, thereby realizing the opening and closing action of the gripper, and finally realizing the gripping or releasing of the control rod assembly 30 by the gripper. It should be noted that the opening and closing of the gripper 20 by the gripper driving rod 13 can be completed by the prior art, and the specific structure of the gripper driving rod 13 and the gripper 20 will not be described here.

[0043] The gripper driving rod 13 is arranged at a distance from the transmission part 12, that is, there is no connection relationship between the gripper driving rod 13 and the transmission part 12. In this example, the rotating part 11 is buckled on part of the top of the transmission part 12 and the top of the gripper driving rod 13, forming a three-level nested structure form, which can effectively reduce the size of the control rod driving assembly in the axial direction, thereby facilitating the miniaturization development of the reactor.

[0044] Continuing to refer to Figure 1 and Figure 2The first parallel transmission assembly 2 is arranged beside the guide tube 10 in the axial direction of the guide tube (i.e. the vertical direction), wherein one end of the first parallel transmission assembly 2 extends into the guide tube 10 and is connected with the transmission member 12, and is used to drive the gripper 20 and the control rod assembly 30 to make linear reciprocating motion in the vertical direction within the guide tube 10.

[0045] The arrangement can be parallel arrangement, vertical arrangement or arrangement at a predetermined angle. For example, the first parallel transmission assembly 2 is parallel to the guide tube 10, i.e. the first parallel transmission assembly 2 is arranged in the vertical direction. Alternatively, the first parallel transmission assembly 2 is arranged in the horizontal direction, and one end of the first parallel transmission assembly 2 is arranged perpendicular to the guide tube 10. Alternatively, the axis of the arrangement direction of the first parallel transmission assembly 2 is at a predetermined angle to the axis of the guide tube 10, i.e. the extension line of the axis of the arrangement direction of the first parallel transmission assembly 2 passes through the axis of the guide tube 10, and the arrangement direction of the guide tube 10 is defined as the vertical direction, and the arrangement direction of the first parallel transmission assembly 2 is arranged in the oblique upward direction or the oblique downward direction. In the present example, the first parallel transmission assembly 2 is arranged in the vertical direction, which reduces the axial size of the drive mechanism and also reduces the radial size of the drive mechanism, thereby facilitating the miniaturization of the reactor.

[0046] Continuing to refer to Figure 1 The second parallel transmission assembly 3 is arranged beside the guide tube 10 in the axial direction of the guide tube (i.e. the vertical direction). One end of the second parallel transmission assembly 3 extends into the guide tube 10 and is connected with the rotating member 11, and the second parallel transmission assembly 3 is used to drive the rotating member 11 to rotate, thereby achieving the opening and closing control of the gripper 20. Specifically, one end of the second parallel transmission assembly 3 extends into the guide tube 10 and is connected with the top of the rotating member 11.

[0047] The arrangement can be parallel arrangement, vertical arrangement or arrangement at a predetermined angle. For example, the second parallel transmission assembly 3 is parallel to the guide tube 10, i.e. the second parallel transmission assembly 3 is arranged in the vertical direction. Alternatively, the second parallel transmission assembly 3 is arranged in the horizontal direction, and one end of the second parallel transmission assembly 3 is arranged perpendicular to the guide tube 10. Alternatively, the axis of the arrangement direction of the second parallel transmission assembly 3 is at a predetermined angle to the axis of the guide tube 10, i.e. the extension line of the axis of the arrangement direction of the second parallel transmission assembly 3 passes through the axis of the guide tube 10, and the arrangement direction of the guide tube 10 is defined as the vertical direction, and the arrangement direction of the second parallel transmission assembly 2 is arranged in the oblique upward direction or the oblique downward direction. In the present example, the second parallel transmission assembly 3 is arranged in the horizontal direction, which effectively reduces the axial size of the control rod drive mechanism, thereby facilitating the miniaturization of the reactor.

[0048] It should be noted that the second parallel transmission assembly 3 is located at a predetermined distance above the first parallel transmission assembly 2. Of course, the second parallel transmission assembly 3 can also be located on the other side of the guide tube 10 at the same position of the first parallel transmission assembly 2, or can also be located below the first parallel transmission assembly 2.

[0049] In the embodiment, the first parallel transmission assembly 2 and the second parallel transmission assembly 3 are located beside the guide tube 10, wherein the first parallel transmission assembly 2 is used to drive the gripper 20 and the control rod assembly 30 to move linearly in the vertical direction in the guide tube, and the second parallel transmission assembly 3 is used to drive the rotating member 11 to rotate and realize the opening and closing control of the gripper 20. At the same time, in cooperation with the nesting form of the three-level nested assembly 1, the axial size of the control rod drive mechanism is effectively reduced, which is conducive to the miniaturization development of the reactor.

[0050] Referring to FIGS. 1 to 3, Figure 1 and Figure 2 As shown in FIGS. 1 to 3, in some embodiments, the rotating member 11 includes a sleeve with an opening at the bottom. The inner wall of the sleeve has a sliding rail groove (not shown in the figure), and one end (the top end) of the gripper driving rod 13 passes through the opening and is connected with the sliding rail groove. In one example, the sliding rail groove can be multiple and arranged in a helical line structure on the inner wall of the sleeve, and the top of the gripper driving rod 13 is provided with multiple sliding rail protrusions (not shown in the figure) connected with the sliding rail groove one by one, so that the rotation of the sleeve realizes the rotation of the gripper driving rod 13 and in turn realizes the opening and closing control of the gripper 20, while ensuring the free sliding of the gripper driving rod 13 in the vertical direction.

[0051] At least part of the transmission member 12 passes through the opening and extends into the sleeve, and the transmission member 12 located in the sleeve is spaced apart from the inner wall of the sleeve by a predetermined distance. It should be noted that the range of the predetermined distance is 3mm-5mm, so as to ensure the smoothness of the movement of the transmission member 12 in the vertical direction in the sleeve.

[0052] In the embodiment, the rotation of the sleeve is finally converted into the opening and closing of the gripper 20 through the adaptive connection of the sliding rail groove in the inner wall of the sleeve and the gripper driving rod 13, so as to complete the gripping or releasing of the control rod assembly 30. That is, part of the gripper driving rod 13 is accommodated in the sleeve. At the same time, at least part of the transmission member 12 is accommodated in the sleeve, so as to realize the three-level nesting form among the rotating member 11, the transmission member 12 and the gripper driving rod 13, effectively reducing the axial size of the control rod drive mechanism. The reduction of the axial size of the control rod drive mechanism is suitable for the design of the small-sized reactor under the premise of realizing the safety function of the reactor, and is conducive to the miniaturization development of the reactor.

[0053] It should be noted that in one example, the rotating member 11 can also be a prism rod. In this case, the lower half of the prism rod is accommodated in the transmission member 12, forming a three-level nested structure. The cross-sectional shape of the prism rod can include a regular polygon. The prism rod is arranged in the gripper driving rod 13. In this case, the gripper driving rod 13 is hollow inside, and the hollow cross-sectional shape of the gripper driving rod 13 is consistent with the shape of the prism rod, so that the rotation of the second parallel transmission assembly 3 drives the rotating member 11, and in turn drives the rotation of the gripper driving rod 13, thereby achieving the opening and closing control of the gripper 20, while ensuring the free sliding of the gripper driving rod in the vertical direction.

[0054] Referring to Figure 1 In some embodiments, the transmission member 12 includes a first gear 121 and a rack 122, and the first gear 121 is in meshing connection with the rack 122.

[0055] In this case, the first gear 121 is in rotational connection with the first parallel transmission assembly 2, that is, the output shaft end of the first parallel transmission assembly 2 is connected with the first gear 121. At least part of the rack 122 is inserted into the rotating member 11 (which can include but is not limited to a sleeve), and the lower end of the rack 122 can be connected with the control rod assembly 30. Under the drive of the first parallel transmission assembly 2, one end of the rack 122 moves in the axial direction of the guide pipe 10 in the rotating member 11, thereby achieving the movement of the control rod assembly 30 in the vertical direction.

[0056] In this embodiment, the first gear 121 and the rack 122 in meshing connection can achieve the control of the movement of the control rod assembly 30, and the structure is simple and convenient for accurate control of the moving position of the control rod assembly 30.

[0057] Referring to Figure 1 In some embodiments, the first parallel transmission assembly 2 includes a first motor 21 and a first gear pair 22. The output shaft end of the first motor 21 is connected with a first speed reducer 23, and the output shaft end of the first speed reducer 23 is connected with the first gear pair 22. In this case, the first speed reducer 23 is used to reduce the output rotating speed of the first motor 21 to the desired number of revolutions, and obtain a larger torque, and at the same time has a reverse self-locking function, thereby accurately controlling the rotating speed and rotating process of the first gear pair 22.

[0058] The output shaft end of the first gear pair 22 is in transmission connection with the first gear 121, and the first gear pair 22 can include but is not limited to a bevel gear pair, which includes a driving bevel gear connected with the output shaft end of the first speed reducer 23 and a driven bevel gear in meshing connection with the driving bevel gear. In this case, the output shaft end of the driven bevel gear in the first gear pair 22 is connected with one end of a transmission rod, and the other end of the transmission rod is connected with the first gear 121, so as to convert the rotation of the first motor 21 into the linear reciprocating motion of the rack 122.

[0059] It should be noted that the first motor 21 and the first speed reducer 23 are arranged in the vertical direction, the bevel gear pair converts the rotation of the first motor 21 in the vertical direction into the rotation of the transmission rod in the horizontal direction, the transmission rod drives the first gear 121 to rotate, and the rotation of the first gear 121 further drives the rack 122 to move. When the first motor 21 rotates forward or reversely, the linear reciprocating movement of the rack 122 in the vertical direction is realized.

[0060] In this embodiment, the first motor 21, the first speed reducer 23, the first gear pair 22, the transmission rod, the transmission member 12, the gripper 20, and the control rod assembly 30 are sequentially connected and form a main transmission line. Referring to Figure 1 As shown, the height of the horizontal position where the highest point of the first motor 21 is located is lower than the height of the horizontal position where the rack 122 is at the highest point, thereby forming a parallel transmission structure by means of the side-by-side arrangement of the first parallel transmission assembly 2 and the gear conversion, effectively reducing the axial size of the control rod drive mechanism.

[0061] Referring to Figure 1 As shown, in some embodiments, the parallel transmission control rod drive mechanism further comprises a rod position measurement assembly 4. The rod position measurement assembly 4 is arranged on the first gear pair 22 to measure the displacement of the control rod assembly 30 through the rotation angle of the transmission gear in the first gear pair.

[0062] The rod position measurement assembly 4 can include an angle measuring instrument to directly measure the rotation angle of the driven bevel gear or the driving bevel gear in the first gear pair 22, and then deduce the displacement of the control rod assembly 30.

[0063] Alternatively, the rod position measurement assembly 4 can include a chain or a measurement rack, which is engaged with the driven bevel gear or the driving bevel gear in the first gear pair 22, so as to measure the rotation angle of the driven bevel gear or the driving bevel gear through the transmission distance of the chain or the movement distance of the measurement rack, and finally deduce and determine the displacement of the control rod assembly 30 through the transmission ratio or the gear speed ratio of the driven bevel gear and the first gear 121 and the rack 122.

[0064] In this embodiment, the relative position of the control rod assembly 30 can be accurately controlled by using the rod position measurement assembly 4, effectively improving the control effect of the control rod assembly 30.

[0065] Referring to Figure 1As shown, in some embodiments, the second parallel transmission assembly 3 reports a second motor 31 and a second gear pair 32. The output shaft end of the second motor 31 is connected to a second speed reducer 33, and the output shaft end of the second speed reducer 33 is connected to the second gear pair 32. The second speed reducer 33 is used to reduce the output speed of the second motor 31 to the desired number of rotations and obtain greater torque, while having a reverse self-locking function, thereby accurately controlling the speed and rotation of the second gear pair 32.

[0066] The output shaft end of the second gear pair 32 is connected to the rotating member 11 to realize the rotation of the rotating member 11 through the rotation of the second motor 31. The second gear pair 32 can include, but is not limited to, a cylindrical gear pair, a bevel gear pair, or a worm gear pair.

[0067] It should be noted that the second motor 31 and the second speed reducer 33 are arranged in the horizontal direction, and the second gear pair 32 converts the rotation of the second motor 31 along the first horizontal position into rotation along the second horizontal position, and the output shaft end of the second gear pair 32 drives the rotating member 11 to rotate. When the second motor 31 rotates forward or reversely, the gripper driving rod 13 rotates and moves vertically relative to the rack 122, thereby controlling the opening and closing state of the gripper 20 by moving the gripper driving rod 13.

[0068] In this embodiment, the second motor 31, the second speed reducer 33, the second gear pair 32, the rotating member 11, the gripper driving rod 13, and the gripper 20 are connected in sequence, thereby realizing the gripping or releasing of the control rod assembly 30 by the gripper 20, and forming a transmission route for the gripping or releasing of the control rod assembly 30. Continuing to refer to Figure 1 As shown, the height of the horizontal position where the highest point of the second motor 31 is located is lower than the height of the horizontal position where the highest point of the rack 122 is located, thereby forming a parallel transmission structure by using the side-by-side arrangement of the second parallel transmission assembly 3 and the gear conversion, effectively reducing the axial size of the control rod driving mechanism.

[0069] Referring to Figure 1 As shown, in some embodiments, the first motor 21 and the second motor 31 are both anti-radiation motors that can resist 10 7 Gray radiation dose to improve the anti-radiation capability of the first motor 21 and the second motor 31, thereby improving the service life.

[0070] Referring to Figure 1As shown, in some embodiments, the parallel transmission control rod drive mechanism further comprises a counterweight (not shown). The counterweight is arranged on the gripper driving rod 13, the rack 122 in the transmission member 12, and the control rod assembly 30. The counterweight is a heavy metal structure with a density greater than that of the coolant in the guide tube 10. Tungsten metal can be selected as the counterweight material according to the type of coolant, or other heavy metal materials can be selected according to the actual type of coolant, so that the total weight of the gripper driving rod 13, the rack 122, the gripper 20, and the control rod assembly 30 is greater than the buoyancy generated by the coolant.

[0071] Referring to Figure 1 As shown, in some embodiments, the parallel transmission control rod drive mechanism further comprises a shielding layer 5. The shielding layer 5 is arranged above the guide tube 10 and covers the exposed part of the three-level nested assembly 1. It should be noted that the shielding layer 5 occupies the gap between the reactor electrical equipment, the three-level nested assembly 1, the first parallel transmission assembly 2, and the third parallel transmission assembly 3 during installation, so as to effectively ensure the radiation resistance of the electrical equipment in the reactor. The shielding layer 5 can also be arranged outside the rotating member 11 and the rack 122, or the shielding layer 5 can be directly coated on the first motor 21, the first speed reducer 23, the second motor 31, and the rod position measurement assembly 4 according to actual conditions. The thickness of the shielding layer 5 can be determined according to the calculation of the neutron flux in the reactor.

[0072] Referring to Figure 1 As shown, in some embodiments, the parallel transmission control rod drive mechanism further comprises a self-locking assembly 6. The self-locking assembly 6 is used to disconnect the control between the first parallel transmission assembly 2 and the transmission member 12 in an accident state, so as to realize the rapid falling and reverse self-locking of the control rod assembly 30. Specifically, after the self-locking assembly 6 disconnects the control between the first parallel transmission assembly 2 and the transmission member 12 in an accident state, the gripper driving member 13, the rack 122, the gripper 20, and the control rod assembly 30 rapidly fall under the action of gravity, and the control rod assembly 30 is reversely locked by the self-locking assembly 6 to prevent rod ejection, thereby realizing the functions of accident rod release and accident self-locking.

[0073] The self-locking assembly 6 can include an electromagnetic clutch and a self-locking structure. The self-locking structure includes but is not limited to an overrunning clutch. The self-locking structure can also use the anti-rebound device in Patent No. CN114093530A (name: Anti-rebound device for compensating rod drive mechanism). The specific structure of the anti-rebound device is not repeated here.

[0074] In this embodiment, the self-locking assembly 6 can disconnect the transmission connection relationship in the accident state, for example, disconnecting between the first speed reducer 23 and the first gear pair 22, thereby ensuring that the control rod assembly 30 can quickly fall and shut down the reactor, and preventing the rod from bouncing, achieving the functions of accident rod release (releasing the control rod assembly 30) and accident self-locking, and ensuring the safety of reactor shutdown.

[0075] In combination Figure 2 And ​ The working process of the parallel transmission control rod drive mechanism for a small reactor of the present application will be described in detail as follows:

[0076] Among them, the working state of the control rod drive mechanism is divided into normal working state, rod falling and shutdown state and installation and maintenance state.

[0077] Normal working state: the second motor 31 drives the rotating part 11 to rotate through the second speed reducer 33 and the second gear pair 32, drives the gripper drive rod 13 to rotate and moves in the vertical direction relative to the rack 122, and then presses the gripper 20 to grab the control rod assembly 30. The first motor 21 drives the control rod assembly 30 to move up and down at a designed speed through the first speed reducer 23, the first gear pair 22 and the transmission part 12. During the operation of the control rod assembly 30, the rod position measuring assembly 4 reacts to the rod position of the control rod assembly 30 in real time.

[0078] Rod falling and shutdown state: taking the electromagnetic clutch and the self-locking structure of the self-locking assembly 6 as an example, the electromagnetic clutch is de-energized, and the control rod assembly 30, the gripper 20, the rack 122 and the gripper drive rod 13 quickly fall and shut down under the action of their own gravity. At the same time, the reverse self-locking function of the self-locking assembly 6 is used to prevent the rod from bouncing.

[0079] Installation and maintenance: the second motor 31 drives the rotating part 11 to rotate, drives the rotating hand drive rod 13 to rotate relative to the rack 122, and makes the gripper 20 in an open state, so that the control rod assembly 30 is self-standing in the core active area, the control rod assembly 30 is separated from the upper end structure, and then the upper end structure can be installed and maintained or the control rod assembly 30 can be refueled by using the refueling mechanism.

[0080] In the parallel transmission control rod assembly drive mechanism of this embodiment, the parallel transmission of the first parallel transmission assembly 2 and the second parallel transmission assembly 3 and the structure of the three-level nested assembly effectively reduce the axial size of the control rod drive mechanism. At the same time, by setting the shielding layer 5, the problem of anti-radiation of electrical equipment caused by the reduction of the axial size of the control rod drive mechanism is solved, which is conducive to the miniaturization of the reactor and effectively improves the safety operation coefficient of the control rod drive mechanism.

[0081] The technical scheme of the present application has been described in combination with the preferred embodiments shown in the drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical schemes after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. A parallel drive control rod drive mechanism for a nuclear reactor for controlling movement of a gripper and a control rod assembly within a guide tube of the nuclear reactor, the gripper for gripping or releasing the control rod assembly, characterized in that, The parallel transmission control rod drive mechanism comprises: a three-level nested assembly comprising a rotating member, a transmission member and a gripper drive rod, projections of the rotating member, the transmission member and the gripper drive rod on a longitudinal section perpendicular to a horizontal plane at least partially coincide, the rotating member is adaptively connected with the gripper drive rod, and the transmission member is arranged in a spaced manner with the gripper drive rod; a first parallel transmission assembly arranged on one side of the three-level nested assembly in a vertical direction, one end of the first parallel transmission assembly is connected with the transmission member, and the first parallel transmission assembly is used to drive the gripper and the control rod assembly to move in the guide pipe; a second parallel transmission assembly arranged on one side of the three-level nested assembly in a horizontal direction, one end of the second parallel transmission assembly is connected with the rotating member, and the second parallel transmission assembly is used to drive the rotating member to rotate and realize opening and closing control of the gripper; wherein the transmission member comprises a first gear and a rack meshing with the first gear, the first gear is rotationally connected with the first parallel transmission assembly, and at least part of the rack is inserted into the rotating member to move in the rotating member in the axial direction of the guide pipe under the drive of the first parallel transmission assembly; the first parallel transmission assembly comprises a first motor, and the height of the horizontal position where the highest point of the first motor is located is lower than the height of the horizontal position where the highest point of the rack is located; the second parallel transmission assembly comprises a second motor, and the height of the horizontal position where the highest point of the second motor is located is lower than the height of the horizontal position where the highest point of the rack is located.

2. The parallel drive control rod drive mechanism for a reactor according to claim 1, characterized by, the rotating member comprises a sleeve with an opening at the bottom, the inner wall of the sleeve has a slide rail groove, one end of the gripper drive rod passes through the opening and is adaptively connected with the slide rail groove; wherein at least part of the transmission member passes through the opening and extends into the sleeve, and the transmission member in the sleeve is spaced apart from the inner wall of the sleeve by a predetermined distance.

3. The parallel drive control rod drive mechanism for a reactor according to claim 1, characterized by the first parallel transmission assembly further comprises a first gear pair; the output shaft end of the first motor is connected with a first speed reducer, and the output shaft end of the first speed reducer is connected with the first gear pair; the output shaft end of the first gear pair is connected with the first gear.

4. The parallel drive control rod drive mechanism for a reactor according to claim 3, characterized by The parallel transmission control rod drive mechanism further comprises a rod position measurement assembly arranged on the first gear pair to measure the displacement of the control rod assembly through the rotation angle of the transmission gear in the first gear pair.

5. The parallel drive control rod drive mechanism for a reactor according to claim 3, characterized by the second parallel transmission assembly further comprises a second gear pair; the output shaft end of the second motor is connected with a second speed reducer, and the output shaft end of the second speed reducer is connected with the second gear pair; the output shaft end of the second gear pair is connected with the rotating member.

6. The parallel drive control rod drive mechanism for a reactor according to claim 5, characterized by The first motor and the second motor are both resistant to 10 7 Anti-radiation motor with a Grahm radiation dose.

7. The parallel drive control rod drive mechanism for a reactor according to any one of claims 1 to 6, characterized by, The parallel transmission control rod drive mechanism further comprises a counterweight, the counterweight is arranged on the gripper drive rod, the transmission member and the control rod assembly, wherein the counterweight is a heavy metal structure with a density greater than that of the coolant in the guide pipe, so that the total weight of the gripper drive rod, the transmission member, the gripper and the control rod assembly is greater than the buoyancy generated by the coolant.

8. The parallel drive control rod drive mechanism for a reactor according to any one of claims 1 to 6, characterized by, The parallel transmission control rod drive mechanism further comprises a shielding layer, which is arranged above the guide pipe and covers the exposed part of the three-level nested assembly.

9. The parallel drive control rod drive mechanism for a reactor according to any one of claims 1 to 6, characterized by, The parallel transmission control rod drive mechanism further comprises a self-locking assembly, which is used to disconnect the control between the first parallel transmission assembly and the transmission member in an accident state, so as to realize the rapid falling and reverse self-locking of the control rod assembly.

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