Control rod drive mechanism and split nut assembly

Abstract

The application discloses a control rod drive mechanism and a split nut assembly. When the second armature is attracted by the armature support, the pushing end on the second armature pushes away the bearing end on the split nut, the pushing end applies a pushing force to the bearing end, the component of the pushing force in the radial direction of the split nut makes each sub-nut approach each other in the radial direction of the sub-nut, the split nut is closed, the corresponding split nut and the lead screw form a ball screw structure, when the split nut rotates, the lead screw can be driven to move in the axial direction of the lead screw, thereby controlling the insertion amount of the control rod into the core barrel. When the armature driving element is powered off, the second armature is separated from the armature support, the sub-nut can be separated from each other in the radial direction of the sub-nut, the rolling element can be separated from the screw thread groove of the lead screw, at this time, the lead screw can fall, and the emergency shutdown is realized. Compared with the existing technology, the structure of the application is simpler and more reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of control rod drive mechanism of nuclear power reactor, more particularly, to a control rod drive mechanism and a split nut assembly. BACKGROUND

[0002] In some types of nuclear reactors, such as pressurized water reactors, the nuclear reaction rate is controlled by the movement of control rods. The control rods include neutron-absorbing material and are arranged to be inserted into the reactor core. The deeper the control rods are inserted into the core, the more neutrons are absorbed, and thus the lower the nuclear reaction rate. Therefore, the amount of insertion of the control rods is controlled to control the reactivity of the reactor.

[0003] In an emergency, the control rods need to be fully inserted into the reactor to quickly stop the nuclear reaction. The control rod drive mechanisms used in the existing domestic and foreign pressurized water reactors (i.e. pressurized water moderated and cooled reactors) are mainly divided into three types, namely rack and pinion type, screw and roller nut type, and magnetic force driven step type. Among them, the screw and roller nut type drives the rotation of the nut to control the axial movement of the screw, thereby controlling the amount of insertion of the control rods into the reactor, through the cooperation of the screw, roller and nut.

[0004] For example, CN105788668A discloses a control rod drive mechanism with a separable nut drive, which includes a separable nut component; the separable nut component is composed of a separable nut, a plurality of connecting rods, an armature, and a release spring and is sleeved in the motor pressure-bearing shell; two of the connecting rods are completely identical; the two completely identical connecting rods, a connecting rod for connecting the rotor shaft sleeve, the armature, and the separable nut constitute a single-degree-of-freedom connecting rod mechanism with a parallelogram structure, and the position of the separable nut is controlled through the up-down movement of the armature; a drive screw component is composed of a core rod, a drive screw, a positioning block, a rod drop spring, and a guide block; one end of the drive screw is connected with a control rod assembly. In this scheme, the separable nut is used to rotate the drive screw to move linearly, which can realize the insertion, extraction and position keeping of the control rod assembly into the core under various operating conditions of the reactor. When a power failure occurs in an emergency safety condition, the drive screw cannot move, at which time the armature is pushed away, the armature pulls the separable nut through the connecting rod, and the separable nut is disengaged from the meshing state of the drive screw, and the drive screw pushes the control rod assembly into the core quickly under the action of the rod drop spring.

[0005] However, in this scheme, in an emergency, the nut can be separated by pulling the connecting rod, disengaging it from the drive screw and thus lowering the rod. Controlling the nut's opening and closing via the connecting rod mechanism presents several challenges. First, the connecting rod mechanism has many degrees of freedom, and after prolonged operation, wear and loosening can occur, making precise control of the nut's opening and closing position impossible. Second, the connecting rod structure contains numerous components and connections, while the nut drive structure in a small reactor is relatively small, making precise arrangement of these components within that space extremely difficult. Furthermore, when the nut is closed, the connecting rod structure has poor self-locking properties; if the screw experiences a large axial force, the nut can easily open, causing the screw to disengage. Summary of the Invention

[0006] This invention provides a control rod drive mechanism and a rupture nut assembly, in which the structure for controlling the opening and closing of the nut is simpler and more reliable.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0008] A splitting nut assembly for mating with a lead screw with a helical groove on its outer side; including a splitting nut and a nut opening and closing drive assembly;

[0009] The opening and closing nut is used to be sleeved on the outside of the lead screw, and a nut helical groove is provided inside. A rolling element is provided in the nut helical groove. The opening and closing nut is formed by multiple sub-nuts that can move and separate along its radial direction.

[0010] The nut opening and closing drive assembly includes an armature support, a second armature, and an armature drive component;

[0011] The armature support is disposed at one end of the opening and closing nut; one end of the second armature is circumferentially disposed on the outside of the opening and closing nut, and the end is provided with a pushing end; several receiving ends are provided on the outside of the opening and closing nut for cooperating with the pushing end; the armature drive is disposed close to the armature support and / or the second armature.

[0012] When the armature drive is energized, the armature support attracts the second armature, causing it to move closer to the opening nut. During this process, the pushing end on the second armature pushes against the receiving end on the opening nut, causing the sub-nuts to move closer to each other radially, allowing the rolling element on the opening nut to engage with the screw helical groove of the lead screw. When the armature drive is de-energized, the second armature disengages from the armature support, and the sub-nuts can separate radially, allowing the rolling element to disengage from the screw helical groove of the lead screw.

[0013] As a further improvement, the outer side of the open-close nut is provided with a plurality of driving blocks, and the receiving end is arranged on the driving blocks; the second armature is provided with a plurality of driving plates corresponding to the driving blocks, and the pushing end is arranged on the driving plates.

[0014] As a further improvement, the receiving end and the pushing end are both arranged in an inclined manner.

[0015] As a further improvement, the inner side of the open-close nut is nested with a second elastic member along the circumferential direction; when the armature driving element is powered off, the second elastic member enables the sub-nuts to separate from each other along the radial direction, so that the open-close nut is unfolded.

[0016] As a further improvement, a support is fixedly arranged on the armature support, the support surrounds the outer side of the open-close nut, and the inner side of the support is provided with a plurality of nut guide rods, at least one nut guide rod penetrates one of the sub-nuts along the radial direction.

[0017] As a further improvement, a locking assembly is further included, and the locking assembly comprises a first armature and at least one locking body.

[0018] The first armature is arranged at one end of the armature support, at least one sliding block is connected to the first armature, and the locking body penetrates the second armature;

[0019] When the armature driving element is powered on, the armature support attracts the second armature to enable the open-close nut to close, and simultaneously attracts the first armature to drive the sliding block to push the locking body to move close to the armature support, so that one side of the locking body is embedded in the armature support, and the open-close nut is locked in the closed state.

[0020] As a further improvement, the second armature is located between the armature support and the first armature, the first armature is connected with the sliding block through a push rod, one side of the armature support is connected with an armature connecting rod, one end of the armature connecting rod penetrates the second armature and is connected with the first armature in a sliding manner, one side of the second armature is connected with an armature guide shaft, and the armature guide shaft penetrates the first armature and is connected with the first armature in a sliding manner.

[0021] As a further improvement, a first elastic member is further arranged between the first armature and the second armature.

[0022] As a further improvement, the locking body is a ball, and one side of the sliding block close to the locking body is arranged in an inclined manner.

[0023] The application further provides a control rod driving mechanism for controlling the insertion amount of a control rod into a core stack, which comprises the split nut assembly and a lead screw according to any one of the preceding items.

[0024] The screw rod is provided with a helical screw groove outside; the screw rod is arranged in the opening and closing nut and arranged axially along the opening and closing nut; the opening and closing nut can drive the screw rod to move along the axial direction when the opening and closing nut rotates;

[0025] When the armature driving element is powered on, the sub-nuts are close to each other along the radial direction, and part of the rolling element on the opening and closing nut is connected with the helical screw groove of the screw rod; when the armature driving element is powered off, the sub-nuts can be separated from each other along the radial direction, so that the rolling element is separated from the helical screw groove of the screw rod.

[0026] Compared with the prior art, the technical scheme provided by the application has the following beneficial effects: when the armature driving element is powered on, the armature support and the second armature have magnetic attraction, at this time, the armature support attracts the second armature, in the process of attraction, the pushing end on the second armature pushes away the receiving end on the opening and closing nut, the pushing end exerts a pushing force on the receiving end, the component of the pushing force in the radial direction of the opening and closing nut makes each sub-nut close to each other along the radial direction, the opening and closing nut is closed, part of the structure of the rolling element on the opening and closing nut can be connected with the helical screw groove of the screw rod, so as to correspond to the opening and closing nut and the screw rod to form a ball screw structure, when the opening and closing nut rotates, the screw rod can be driven to move along the axial direction, thereby controlling the insertion amount of the control rod into the core; when the armature driving element is powered off, the attraction between the armature support and the second armature is eliminated, the second armature is separated from the armature support, and the sub-nuts can be separated from each other along the radial direction under the action of an external force, so that the rolling element can be separated from the helical screw groove of the screw rod, at this time, the screw rod can fall under the action of its own gravity, and the control rod falls into the core along with the screw rod to realize emergency shutdown. Compared with the existing technology which uses a connecting rod structure to control the opening and closing of the opening and closing nut, the structure of the present application is simpler and more reliable.

[0027] Other technical problems solved by the control rod driving mechanism and the split nut assembly of the application, other technical features included in the technical scheme, and advantages brought by these technical features will be further described in detail with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the front view of the assembly structure of the opening and closing nut and the nut opening and closing driving assembly;

[0029] Figure 2 is the perspective view of the assembly structure of the opening and closing nut and the nut opening and closing driving assembly;

[0030] Figure 3 is another angle perspective view of the assembly structure of the opening and closing nut and the nut opening and closing driving assembly;

[0031] Figure 4The exploded view of the assembly structure of the open-close nut and the open-close nut driving assembly;

[0032] Figure 5 The exploded view of the assembly structure of the open-close nut and the open-close nut driving assembly;

[0033] Figure 6 The schematic view of the overall structure of the control rod driving mechanism;

[0034] Figure 7 The schematic view of the overall structure of the control rod driving mechanism; Figure 6 The schematic view of the overall structure of the control rod driving mechanism;

[0035] Figure 8 The schematic view of the overall structure of the control rod driving mechanism; Figure 7 The schematic view of the overall structure of the control rod driving mechanism;

[0036] Figure 9 The schematic view of the overall structure of the control rod driving mechanism; Figure 7 The schematic view of the overall structure of the control rod driving mechanism;

[0037] Figure 10 The schematic view of the overall structure of the control rod driving mechanism;

[0038] The schematic view of the overall structure of the control rod driving mechanism;

[0039] 1, screw rod; 11, screw thread groove; 2, shell; 3, armature driving member;

[0040] 41, first armature; 411, push rod; 412, guide through hole; 413, counterbore;

[0041] 42, second armature; 421, driving plate; 4211, pushing end; 422, first through hole; 423, armature guide shaft; 424, sliding block; 425, first elastic member; 426, locking body; 427, armature locking baffle;

[0042] 43, armature support; 431, armature connecting rod; 432, support locking baffle;

[0043] 44, open-close nut; 441, driving block; 4410, receiving end; 442, nut guide hole; 443, nut screw thread groove; 444, second elastic member;

[0044] 45, support; 451, support plate; 452, nut guide rod;

[0045] 46, support connecting section;

[0046] 47, rotating bearing. DETAILED DESCRIPTION

[0047] For further understanding of the present application, the present application is described in detail in combination with the drawings and examples.

[0048] The structure, proportion, size, etc. shown in the drawings of the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not have technical substantive significance, and any modification of the structure, change of the proportion relationship, or adjustment of the size, without affecting the effect and purpose that can be achieved by the application, should still fall within the scope of the disclosed technology.

[0049] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the devices, elements or components indicated to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to indicating the orientation or positional relationship, the above-mentioned terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0050] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein.

[0051] Some of the terms "mounting", "setting", "provided with", "connection" in the present application should be understood broadly. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0052] As shown in Figure 6 , Figure 7 and Figure 8 , the present application provides a control rod drive structure applied in a nuclear reactor to control the insertion amount of the control rod into the core. The drive structure controls the insertion amount of the control rod into the core, and the deeper the control rod is inserted into the core, the more neutrons are absorbed, and thus the nuclear reaction rate is reduced. Moreover, in an emergency, the control structure also needs to drop the control rod in an emergency, so that the control rod is fully inserted into the core.

[0053] As Figures 1-5 shown in the drawings, the present application also provides a split nut assembly for cooperating with a lead screw 1 having a helical slot 11 on the outer side. Specifically, it comprises a split nut 44 and a split nut driving assembly.

[0054] The split nut 44 is arranged to be sleeved on the outer side of the lead screw 1, and the split nut 44 is provided with a nut helical slot 443, and the nut helical slot 443 is provided with a rolling element. The split nut 44 is formed by a plurality of sub-nuts that can move radially to separate. The nut helical slot 443 is intermittent, and each section is located on each sub-nut. When the split nut 44 is connected with the lead screw 1, the nut helical slot 443 corresponds in position with the lead screw helical slot 11, and the rolling element is located in the nut helical slot 443 on one side and in the lead screw helical slot 11 on the other side, thereby forming a ball screw structure, so that the split nut 44 can drive the lead screw 1 to move in the axial direction when the split nut 44 rotates. Moreover, the lead screw 1 is arranged vertically.

[0055] Further, the split nut driving assembly comprises an armature support 43, a second armature 42 and an armature driving element 3. Specifically, the armature support 43 is arranged at one end of the split nut 44, and the second armature 42 is arranged around the outer side of the split nut 44 at one end, and the end is provided with a pushing end 4211. The second armature 42 can move towards or away from the armature support 43, and the outer side of the split nut 44 is provided with a plurality of receiving ends 4410 for cooperating with the pushing end 4211. The armature driving element 3 is arranged close to the armature support 43 and the second armature 42. Specifically, when the armature driving element 3 is energized, the armature support 43 attracts the second armature 42 to move close to the split nut 44. During this process, the pushing end 4211 on the second armature 42 pushes the receiving end 4410 on the split nut 44, so that the sub-nuts move radially towards each other, and part of the rolling element on the split nut 44 can cooperate with the lead screw helical slot 11 of the lead screw 1. When the armature driving element 3 is de-energized, the second armature 42 is separated from the armature support 43, and the sub-nuts can move radially away from each other, so that the rolling element can be separated from the lead screw helical slot 11 of the lead screw 1.

[0056] In the scheme, in order to drive the nut opening and closing drive assembly to rotate, a drive machine is further provided, and the armature support 43 is fixedly provided relative to the drive machine. As a specific embodiment, the armature driving part 3 is selected as an electromagnetic coil, for example, the armature driving part 3 is arranged outside the armature support 43 and the second armature 42. Otherwise, the armature driving part 3 can also be located outside the armature support 43 or outside the second armature 42. When the armature driving part 3 is energized, the armature support 43 and the second armature 42 have an attracting magnetic force, at this time the armature support 43 attracts the second armature 42, and in the process of attraction, the abutting end 4211 on the second armature 42 abuts and pushes away the receiving end 4410 on the opening and closing nut 44, the abutting end 4211 exerts an abutting force on the receiving end 4410, and the component of the abutting force in the radial direction of the opening and closing nut 44 makes each sub-nut move close to each other in the radial direction, the opening and closing nut 44 is closed, and part of the structure of the rolling element on the opening and closing nut 44 can be connected with the screw thread groove 11 of the screw rod 1. When the armature driving part 3 is de-energized, the attracting force between the armature support 43 and the second armature 42 is eliminated, the second armature 42 is separated from the armature support 43, and the sub-nuts can move away from each other in the radial direction under the action of an external force, so that the rolling element can be separated from the screw thread groove 11 of the screw rod 1.

[0057] It should be noted that the external force for moving the sub-nuts away from each other in the radial direction can come from different situations.

[0058] In combination Figure 3 As shown in the figure, in one case, the inner side of the opening and closing nut 44 is nested with the second elastic element 444 in the circumferential direction; when the armature driving part 3 is de-energized, the second elastic element 444 exerts an elastic force on each sub-nut to move the sub-nuts away from each other, and at the same time, the sub-nuts are quickly moved away from each other, so that the opening and closing nut 44 is unfolded. Regarding the arrangement of the second elastic element 444, a groove can be formed in the inner side of the opening and closing nut 44, and the second elastic element 444 is embedded in the groove, and after the second elastic element 444 is embedded in the groove, the side edge of the second elastic element 444 cannot exceed the inner side of the opening and closing nut 44, so as to avoid interference between the second elastic element 444 and the screw rod 1. In addition, in the case of arranging the second elastic element 444, when the abutting end 4211 exerts an abutting force on the receiving end 4410, the elastic force of the second elastic element 444 also needs to be overcome, so that each sub-nut can move close to each other in the radial direction.

[0059] In another case, the second elastic element 444 can also not be arranged. In this case, when the armature driving part 3 is de-energized, the attracting force between the armature support 43 and the second armature 42 is eliminated, and after the second armature 42 is separated from the armature support 43, the abutting end 4211 no longer exerts an abutting force on the receiving end 4410, at this time the opening and closing nut 44 is in a loosened state, the screw rod 1 falls under the action of gravity, and in the falling process, the outer surface of the screw rod interferes with the rolling element, thereby pushing the sub-nuts away from each other.

[0060] As a further improvement, as shown in Figure 3 、 Figure 4 and Figure 5 , the outer side of the open-close nut 44 is convexly formed with a plurality of driving blocks 441, and the receiving end 4410 is arranged on the driving block 441. The second armature 42 is provided with a plurality of driving plates 421 corresponding to the driving blocks 441, and the pushing end 4211 is arranged on the driving plate 421, and the driving plate 421 is arranged around the outer side of the open-close nut 44. The driving blocks 441 are arranged circumferentially along the outer side of the open-close nut 44, and the number and position of the driving plates 421 correspond to the driving blocks 441.

[0061] Preferably, the receiving end 4410 and the pushing end 4211 are both arranged obliquely. Specifically, as shown in Figure 4 , the receiving end 4410 is arranged on the lower side of the driving block 441, and the pushing end 4211 is arranged on the upper side of the driving plate 421, and the receiving end 4410 and the pushing end 4211 are both arranged obliquely, and the thickness of the driving block 441 gradually increases from the lower end to the upper end at the receiving end 4410. When the pushing end 4211 moves upward with the second armature 42, the inclined side of the pushing end 4211 moves upward along the inclined side of the receiving end 4410, and the thickness of the driving block 441 gradually increases from the lower end to the upper end at the receiving end 4410, so that the pushing end 4211 extrudes the driving block 441, further extrudes the open-close nut 44, and the sub-nuts are closer to each other. The oblique arrangement of the receiving end 4410 and the pushing end 4211 makes it easier for the pushing end 4211 to move along the receiving end 4410, thereby making it easier to push the sub-nuts closer to each other.

[0062] As shown in Figure 4 and Figure 5 , a support 45 is further provided, and the armature support 43 is fixedly arranged on the support 45. The support 45 is arranged around the outer side of the open-close nut 44, and specifically, the support 45 includes a plurality of support plates 451 arranged at intervals, and each support plate 451 is arranged on the outer side of the open-close nut 44 and avoids the driving block 441.

[0063] As a further improvement, the inner side of the support 45 is provided with a plurality of nut guide rods 452, at least one nut guide rod 452 is radially provided on a sub-nut. As a preferred embodiment, the nut guide rod 452 is provided on the inner side of the support plate 451, two nut guide rods 452 are provided on the inner side of each support plate 451, and the other end of the nut guide rod 452 is provided on the sub-nut. Each sub-nut is provided with a nut guide hole 442 corresponding to the nut guide rod 452. When the sub-nuts move towards each other and away from each other, the sub-nuts move along the nut guide rod 452, and the nut guide rod 452 guides the sub-nut to avoid deflection during movement. In addition, the support plate 451 is provided on the outer side of the opening and closing nut 44, and when the sub-nuts move away from each other, the outer side of the sub-nut moves to abut against the inner side of the support plate 451, and the support plate 451 limits the opening and closing nut 44. It should be noted that when the nut guide rod 452 cooperates with the nut guide hole 442, the end of the nut guide rod 452 away from the support plate 451 cannot exceed the inner surface of the opening and closing nut 44 to avoid interference with the screw rod 1.

[0064] As another embodiment, as shown in Figure 8 、 Figure 9 and Figure 10 , further comprising a locking assembly, the locking assembly comprising a first armature 41 and at least one movable locking body 426. For example, the locking body 426 can be provided as 1, 2, and 3, etc. In this scheme, the locking body 426 is provided as 3.

[0065] Specifically, the first armature 41 is provided at one end of the armature support 43, and at least one sliding block 424 is connected to the first armature 41, and the locking body 426 is provided through the second armature 42. When the armature driving element 3 is energized, the armature support 43 attracts the second armature 42 to close the opening and closing nut 44, and at the same time attracts the first armature 41 to drive the sliding block 424 to push the locking body 426 to move close to the armature support 43, so that one side of the locking body 426 is embedded in the armature support 43, and the opening and closing nut 44 is locked in the closed state. As a further improvement, the number and position of the sliding block 424 correspond to the arrangement of the locking body 426, the sliding block 424 is located on the outer side of the driving plate 421 of the second armature 42, and the armature support 43 is also located on the inner side of the driving plate 421 of the second armature 42. When the first armature 41 is attracted, the first armature 41 drives the sliding block 424 to move, and the sliding block 424 pushes the locking body 426 to move close to the armature support 43. The armature support 43 is provided with a recess space capable of accommodating part of the structure of the locking body 426, and after the locking body 426 is pushed, the part of the structure passes through the inner side wall of the driving plate 421 and is embedded in the recess space, and at the same time, the side of the locking body 426 close to the sliding block 424 abuts against the sliding block 424, and the locking body 426 is locked by the sliding block 424.

[0066] As a further improvement, the second armature 42 is located between the armature support 43 and the first armature 41, and the first armature 41 is connected with the slider 424 through the push rod 411.

[0067] Specifically, see Figure 4 In detail, one side of the armature support 43 is connected with the armature connecting rod 431, and one end of the armature connecting rod 431 is connected with the first armature 41 through the first through hole 422 of the second armature 42. In detail, the first through hole 422 is formed on the second armature 42, and the counterbore 413 is formed on the first armature 41. One end of the armature connecting rod 431 is inserted into the counterbore 413 through the first through hole 422, and the end of the armature connecting rod 431 further has a limiting baffle, and the limiting baffle has a size larger than the diameter of the first through hole 422, so that the armature connecting rod 431 can guide the movement of the second armature 42 while limiting the second armature 42 through the limiting baffle to avoid falling off.

[0068] In addition, one side of the second armature 42 is connected with the armature guide shaft 423, and the armature guide shaft 423 is connected with the first armature 41 through the first armature 41. In detail, the guide through hole 412 is formed on the first armature 41, and the armature guide shaft 423 is arranged through the guide through hole 412, and the armature guide shaft 423 guides the movement of the first armature 41 in cooperation with the guide through hole 412.

[0069] Preferably, the locking body 426 is a ball, and one side of the slider 424 close to the locking body 426 is inclined. The locking body 426 is arranged as a ball, which can move flexibly to avoid jamming. The one side of the slider 424 close to the locking body 426 is inclined, which facilitates the pushing of the locking body 426.

[0070] As shown in Figure 8 and Figure 9 , regarding the locking effect of the locking body 426, it also needs to be explained that, as shown in Figure 9 and the view direction in Figure 9 . The upper side of the locking body 426 is located inside the driving plate 421 and protrudes to form an armature locking baffle 427, and the outer side of the armature support 43 protrudes to form a support locking baffle 432. When the first armature 41 is attracted, one side of the locking body 426 is embedded in the recessed space on the outer side of the armature support 43 when the slider 424 moves, at this time, the armature locking baffle 427 and the support locking baffle 432 are tightly close together to form a mutual limiting state. Because the first armature 41 is attracted, part of the structure of the locking body 426 is embedded in the armature support 43, and part of the structure is located in the driving plate 421 of the second armature 42, and at the same time, the other side of the locking body 426 is tightly close to the slider 424, so that the abutting end 4211 on the driving plate 421 tightly abuts against the bearing end 4410, avoiding that the lead screw moves under the external force when a larger external force is suddenly applied to the lead screw, and the opening and closing nut 44 is opened.

[0071] When the armature driving member 3 is powered off, the attraction force between the first armature 41 and the armature support 43 is eliminated, and the first armature 41 falls. One side of the sliding block 424 is provided with a structure capable of limiting the outer side of the driving plate 421, and the sliding block 424 cooperates with the driving plate 421 to limit the first armature 41, so as to avoid the first armature 41 from falling off.

[0072] As for the falling of the first armature 41, see Figure 9 , the first armature 41 can fall under the action of its own gravity. In addition, a first elastic member 425 can be arranged between the first armature 41 and the second armature 42, so that the first armature 41 falls rapidly under the action of its own gravity and the elastic force of the first elastic member 425, and drives the sliding block 424 to quickly remove the resistance to the locking body 426, at this time, the second armature 42 falls to drive the locking body 426 to escape from the recessed space outside the armature support 43, and the pushing end 4211 on the driving plate 421 no longer pushes the bearing end 4410, and the opening and closing nut 44 is unfolded.

[0073] In this scheme, in order to protect the opening and closing nut 44, an outer shell 2 is further arranged. Specifically, the outer shell 2 is sleeved on the outer side of the armature driving member 3. In order to further improve the locking effect, the outer sides of the driving plate 421 and the sliding block 424 can be closely arranged on the inner side of the armature driving member 3, and the armature driving member 3 is used to apply a radial force to the driving plate 421 and the sliding block 424, so as to further avoid the opening and closing nut 44 from being unfolded under the sudden external force in the locked state.

[0074] As shown in Figure 1 and Figure 8 , the outer side of the support 45 is further sleeved with a rotating bearing 47. Specifically, the upper end of the support 45 has a support connecting section 46, and the rotating bearing 47 is sleeved on the support connecting section 46. The inner ring of the rotating bearing 47 is fixed relative to the support connecting section 46. In one case, the support connecting section 46 is integrally formed with the other part of the support 45; in other cases, the support 45 can also be separately arranged with the other part of the support 45, and is fixedly connected through bolts or screws.

[0075] The control rod driving mechanism provided by the application is used to control the insertion amount of the control rod into the core pile, and specifically comprises the cracking nut assembly and the lead screw 1. The lead screw 1 is vertically arranged, and a helical lead screw groove 11 is formed in the outer side of the lead screw 1. The lead screw 1 is arranged in the opening and closing nut 44 and is arranged in the axial direction of the opening and closing nut 44. When the driving machine drives the opening and closing nut 44 to rotate, the lead screw 1 can be driven to move in the axial direction, so as to control the insertion amount of the control rod into the core pile.

[0076] In one case, the driving machine is a motor, and the outer ring of the rotating bearing 47 is fixedly connected with a gear, and the gear is in transmission connection with the output shaft of the motor, so that when the motor rotates, the gear drives the opening and closing nut 44 to rotate.

[0077] When the armature driving element 3 is powered, the sub-nuts are close to each other in the radial direction, the parts of the rolling elements on the opening and closing nut 44 are connected with the screw thread groove 11 of the screw rod 1, the opening and closing nut 44 and the screw rod 1 form a ball screw structure, and the opening and closing nut 44 can drive the screw rod 1 to move when rotating. In an emergency, the armature driving element 3 is powered off, the sub-nuts can be separated from each other in the radial direction, so that the rolling elements are separated from the screw thread groove 11 of the screw rod 1, at this time the screw rod 1 can fall under the action of its own gravity, and the control rod falls into the core with the screw rod 1 to achieve emergency shutdown.

[0078] The above description of the present application and its embodiments is illustrative and not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the present application, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it, without departing from the purpose of the present application, similar structural modes and embodiments can be designed without creativity, which should belong to the protection scope of the present application.

Claims

1. A pyrolysis nut assembly for mating with a lead screw (1) having a helical groove (11) on its outer side; characterized in that: Includes a nut (44) and a nut opening and closing drive assembly; The opening and closing nut (44) is used to be sleeved on the outside of the lead screw (1), and a nut helical groove (443) is provided inside. A rolling element is provided inside the nut helical groove (443); the opening and closing nut (44) is formed by a plurality of sub-nuts that can be moved and separated along its radial direction. The nut opening and closing drive assembly includes an armature support (43), a second armature (42), and an armature drive component (3); The armature support (43) is disposed at one end of the opening nut (44); one end of the second armature (42) is circumferentially disposed on the outside of the opening nut (44), and the end is provided with a push end (4211); a plurality of receiving ends (4410) are provided on the outside of the opening nut (44) for cooperating with the push end (4211); the armature drive (3) is disposed close to the armature support (43) and / or the second armature (42); When the armature drive (3) is powered on, the armature support (43) attracts the second armature (42) and moves it close to the opening nut (44). During this process, the pushing end (4211) on the second armature (42) pushes against the receiving end (4410) on the opening nut (44), causing the sub-nuts to move closer to each other in their radial direction, so that the rolling part on the opening nut (44) can engage with the screw helical groove (11) of the screw (1). When the armature drive (3) is de-energized, the second armature (42) disengages from the armature support (43), and the sub-nuts can separate from each other in their radial direction, so that the rolling part can disengage from the screw helical groove (11) of the screw (1).

2. The pyrolysis nut assembly according to claim 1, characterized in that: The outer side of the opening and closing nut (44) protrudes to form a plurality of driving blocks (441), and the receiving end (4410) is disposed on the driving block (441); the second armature (42) is provided with a plurality of driving plates (421) corresponding to the driving block (441), and the pushing end (4211) is disposed on the driving plate (421).

3. The pyrolysis nut assembly according to claim 1 or 2, characterized in that: Both the receiving end (4410) and the pushing end (4211) are inclined.

4. The pyrolysis nut assembly according to claim 1, characterized in that: The inner side of the opening and closing nut (44) is nested with a second elastic element (444) along its circumference; when the armature drive (3) is de-energized, the second elastic element (444) causes the sub-nut to quickly separate from each other along its radial direction, so that the opening and closing nut (44) unfolds.

5. The pyrolysis nut assembly according to claim 4, characterized in that: A support (45) is fixedly installed on the armature support (43). The support (45) surrounds the outside of the opening nut (44), and a plurality of nut guide rods (452) are provided on the inner side of the support (45). At least one nut guide rod (452) passes radially through a sub-nut.

6. The pyrolysis nut assembly according to claim 1, characterized in that: It also includes a locking assembly, which includes a first armature (41) and at least one locking body (426); The first armature (41) is disposed at one end of the armature support (43), and at least one slider (424) is connected to the first armature (41). The locking body (426) passes through the second armature (42). When the armature drive (3) is powered on, the armature support (43) attracts the second armature (42) to close the opening nut (44), and at the same time attracts the first armature (41) to drive the slider (424) to push the locking body (426) closer to the armature support (43), so that one side of the locking body (426) is embedded in the armature support (43), and the opening nut (44) is locked in the closed state.

7. The pyrolysis nut assembly according to claim 6, characterized in that: The second armature (42) is located between the armature support (43) and the first armature (41). The first armature (41) is connected to the slider (424) via a push rod (411). One side of the armature support (43) is connected to the armature connecting rod (431). One end of the armature connecting rod (431) passes through the second armature (42) and is slidably connected to the first armature (41). One side of the second armature (42) is connected to the armature guide shaft (423). The armature guide shaft (423) passes through the first armature (41) and is slidably connected to the first armature (41).

8. The pyrolysis nut assembly according to claim 6, characterized in that: A first elastic element (425) is also provided between the first armature (41) and the second armature (42).

9. The pyrolysis nut assembly according to claim 6, characterized in that: The locking body (426) is a ball bearing, and the slider (424) is inclined on the side near the locking body (426).

10. A control rod drive mechanism for controlling the insertion depth of a control rod into a core stack, characterized in that: Including the pyrolysis nut assembly and lead screw (1) as described in any one of claims 1-9, The lead screw (1) has a spiral groove (11) on its outer side; the lead screw (1) is inserted into the opening nut (44) and is arranged along the axial direction of the opening nut (44); when the opening nut (44) rotates, it can drive the lead screw (1) to move along its axial direction. When the armature drive (3) is powered on, the sub-nuts move closer to each other along its radial direction, and the rolling element on the opening and closing nut (44) is engaged with the screw helical groove (11) of the screw (1); when the armature drive (3) is de-energized, the sub-nuts can separate from each other along its radial direction, so that the rolling element disengages from the screw helical groove (11) of the screw (1).

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