Magnetic levitation type control rod drive mechanism and drive method
Patent Information
- Application Number
- CN202611308411.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-26
- Publication Date
- 2026-11-03
Smart Images
Figure CN123033782A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of nuclear engineering technology, specifically to a magnetically levitated control rod drive mechanism and drive method. Background Technology
[0002] The control rod drive mechanism (CRDM) is a core component for nuclear reactor reactivity regulation and emergency shutdown, and is directly related to the safety, stability and controllability of nuclear reactor operation.
[0003] Currently, pressurized water reactor nuclear power plants widely employ magnetic lifting (stepping) control rod drive mechanisms. This type of drive mechanism primarily relies on the engagement of electromagnetic coils to drive pawls that grip an annular groove on the drive rod. Through the mechanical engagement of the pawls and the drive rod's annular groove, the drive rod is lifted or held in position in a step-by-step manner. Specifically, generally, when the lifting magnetic poles are engaged, the lifting armature is driven, and through a transmission mechanism, the pawls open or close, gripping the drive rod's annular groove to achieve step-by-step lifting. When the holding magnetic poles are engaged, the holding pawls grip the drive rod's annular groove to achieve static holding. When all electromagnetic coils are de-energized, the drive rod falls freely under gravity to achieve emergency rod lowering, etc.
[0004] The aforementioned magnetic lifting step-type drive mechanism has the following drawbacks in long-term operation: The driving force is transmitted through rigid mechanical meshing between the pawl and the drive rod annular groove. Over time, tooth surface wear, plastic deformation, and fatigue cracks lead to increased meshing clearance, decreased positioning accuracy, and even slippage or clamping failure. Transmission components such as the pawl pin also face the risk of wear failure. The step-type motion involves acceleration and sudden stops with each step, generating significant mechanical impact loads, exacerbating wear and causing fastener loosening, seal fatigue, and structural stress concentration. The mechanical meshing and disengagement processes generate significant noise and vibration, affecting operational stability and surrounding equipment. The cumulative effects of wear, impact, and vibration make the pawl, drive rod annular groove, and pin become bottleneck components in terms of lifespan. Furthermore, these components are located within the primary circuit pressure boundary, making maintenance and replacement difficult in high-temperature, high-radiation environments. Excessive wear necessitates reactor shutdown for maintenance, impacting the nuclear power plant's availability. In addition, the step-type motion is stepped and adjustable, limiting the precision of reactor power control.
[0005] Therefore, there is an urgent need in the field to develop a new control rod driving mechanism. This application proposes a magnetically levitated control rod driving mechanism and driving method to solve one or more of the above-mentioned technical problems. Summary of the Invention
[0006] The first aspect of this application aims to provide a magnetically levitated control rod drive mechanism.
[0007] The second aspect of this application aims to provide a method for driving a magnetically levitated control rod.
[0008] According to the first aspect of this application, a magnetically levitated control rod drive mechanism includes a pressure-resistant housing component, a stator component, and a moving component; wherein, the stator component is fixed to the pressure-resistant housing component, the stator component includes a plurality of electromagnet units arranged axially, each electromagnet unit including an iron core and an excitation coil wound around the iron core; the moving component includes a magnetic component and a drive rod connected to each other, and the moving component is movably disposed axially inside the pressure-resistant housing component; an air gap is provided between the stator component and the moving component, and the magnetically levitated control rod drive mechanism is configured such that: when the excitation coil is energized, the electromagnet units can electromagnetically couple with the magnetic component to generate an axial force acting on the moving component; the magnetically levitated control rod drive mechanism further includes a radial support component, the radial support component being fixed to the pressure-resistant housing component, for keeping the moving component centered under eccentric conditions.
[0009] Compared to the traditional magnetic lifting (stepping) control rod drive mechanism described above, the magnetic levitation control rod drive mechanism provided in this application generates axial force by electromagnetically coupling the electromagnet unit and magnetic components through the energization of the excitation coil. This electromagnetic coupling replaces the traditional mechanical engagement between the pawl and the drive rod annular groove to provide driving and holding forces, fundamentally eliminating frictional contact between the pawl and the drive rod. This effectively avoids the mechanical wear, impact loads, and noise and vibration problems associated with traditional magnetic lifting (stepping) control rod drive mechanisms. Furthermore, the electromagnetic coupling method allows for the instantaneous generation of electromagnetic force when the excitation coil is energized, reducing mechanical transmission backlash and transmission delay, thus facilitating rapid response and precise positioning adjustment. The axial force of the electromagnet unit can be continuously adjusted through the excitation current, resulting in higher position control accuracy of the drive rod compared to traditional stepping mechanisms, which is beneficial for achieving precise adjustment of reactor power. The radial support component is set up to keep the moving part centered under eccentric conditions, avoiding direct contact between the moving part and the electromagnet unit of the stator component, thus further ensuring the reliability of the magnetic levitation contactless operation. As a result, the magnetic levitation control rod drive mechanism provided in this application significantly reduces the mechanical wear of the control rod drive mechanism, which is conducive to improving operational reliability and extending service life.
[0010] In some embodiments, the radial support member is a slip ring, and there is a gap between the radial support member and the moving part, and the gap between the radial support member and the moving part is smaller than the gap between the electromagnet unit and the magnetic component.
[0011] In some embodiments, the radial support component includes a slip ring and / or a magnetic bearing.
[0012] In some embodiments, the surfaces of the mover component and / or the stator component are covered with a shielding sleeve, which is used to isolate coolant and shield radiation.
[0013] In some embodiments, the air gap consists only of the mechanical clearance and the wall thickness of the shielding sleeve.
[0014] In some embodiments, the magnetic component includes a permanent magnet.
[0015] In some embodiments, the magnetic component includes samarium cobalt permanent magnets and soft magnets stacked alternately along the axial direction.
[0016] In some embodiments, a permanent magnet is integrated inside the iron core, and the magnetic component includes a soft magnet.
[0017] In some embodiments, the pressure vessel component includes a rod travel shell, a stator mounting shell, and a top penetration member arranged from top to bottom, and its inner cavity communicates with the reactor pressure vessel. The stator component is fixed inside or outside the stator mounting shell, the rotor component is suspended in the air gap, and the top penetration member is used to pass through the reactor pressure vessel.
[0018] According to the magnetic levitation control rod driving method of the second aspect of this application, a magnetic levitation control rod driving mechanism as described in the first aspect is used to drive the control rod, the method comprising: A current is passed through the excitation coil to electromagnetically couple the electromagnet unit with the magnetic component, thereby generating an axial force acting on the moving part. By adjusting the axial force, the drive rod can be moved axially or kept in position. In eccentric operation, the radial support component keeps the moving part centered. Attached Figure Description
[0019] The above and other features, properties, and advantages of this application will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features. It should be noted that these drawings are merely illustrative and are not drawn to scale, and should not be construed as limiting the scope of protection actually claimed by this application, wherein: Figure 1 This is a schematic diagram of the structure of a magnetic levitation control rod drive mechanism according to one embodiment.
[0020] Figure 2 for Figure 1 A partial cross-sectional schematic diagram of the magnetic levitation control rod drive mechanism is shown.
[0021] Figure 3 for Figure 1Another partial cross-sectional schematic diagram of the magnetic levitation control rod drive mechanism shown.
[0022] Figure 4 for Figure 1 A partial cross-sectional schematic diagram of the stator component of the magnetic levitation control rod drive mechanism shown.
[0023] Figure 5 for Figure 1 A partial cross-sectional schematic diagram of the moving part of the magnetic levitation control rod drive mechanism shown.
[0024] Explanation of reference numerals in the attached figures: 1. Magnetic levitation control rod drive mechanism; 11. Pressure shell components; 111. Rod travel shell; 112. Stator mounting shell; 113. Top penetration; 114. Extension shell; 115. Electrical penetration; 12. Stator components; 121. Iron core; 122. Excitation coil; 123. Inner shielding sleeve; 124. Outer shielding sleeve; 13. Moving part; 131. Magnetic part; 1311. Permanent magnet; 1312. Soft magnet; 132. Drive rod; 133. Moving part shielding sleeve; 14. Radial support components; 15. Rod position detector; 16. Heat insulation sleeve. Detailed Implementation
[0025] Reference will now be made in detail to various embodiments of this application, examples of which are shown in the accompanying drawings and described below. Although this application will be described in conjunction with exemplary embodiments, it should be understood that this application is not intended to be limited to those exemplary embodiments. Rather, this application is intended to cover not only these exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of this application as defined by the appended claims.
[0026] This application uses specific terms to describe embodiments of the application. For example, "an embodiment" and / or "one embodiment" refers to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment" or "one embodiment" mentioned twice or more in different locations in this application does not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.
[0027] In this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying positional relationships or order of importance.
[0028] In the following description, the orientation or positional relationship indicated by terms such as "upper," "lower," "inner," "outer," "front," "back," or other directional terms is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed and / or be implemented in a specific orientation, and therefore should not be construed as a limitation of this application.
[0029] In the following description, unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," "contact," etc., should be interpreted broadly; for example, they can refer to fixed connections or movable connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this application according to the specific circumstances.
[0030] See Figures 1 to 5 As shown, this application provides a magnetically levitated control rod drive mechanism 1, which includes a pressure-resistant shell component 11, a stator component 12, and a mover component 13.
[0031] The pressure shell component 11 is part of the pressure boundary of the reactor primary coolant system, and its interior forms a channel for the movement of the actuator component 13, which is connected to the reactor pressure vessel.
[0032] The stator component 12 is fixed to the pressure-resistant housing component 11. The stator component 12 includes multiple electromagnet units arranged axially. Each electromagnet unit specifically includes an iron core 121 and an excitation coil 122 wound around the iron core 121. Generally, the iron core 121 is made of high-permeability silicon steel sheets to provide a low magnetic reluctance magnetic circuit path. The excitation coil 122 is made of nuclear-grade electrical cables and can withstand primary circuit radiation, high-temperature environments, etc., without being limited by these. The multiple electromagnet units can be uniformly arranged axially. Each electromagnet unit independently generates an electromagnetic field. By independently controlling the current, timing, and direction of the excitation coil 122 of each electromagnet unit, a controllable magnetic field is formed within the axial range of the stator component 12.
[0033] The moving part 13 includes a magnetic part 131 and a drive rod 132, and the moving part 13 is axially movably disposed inside the pressure-resistant housing part 11. The magnetic part 131 is connected to the drive rod 132. The end of the drive rod 132 is used to connect a control rod, which will not be described in detail here.
[0034] The magnetic component 131 and the electromagnet unit of the stator component 12 are arranged in corresponding positions to achieve electromagnetic coupling, and an air gap is provided between the stator component 12 and the mover component 13.
[0035] The magnetic levitation control rod drive mechanism 1 is configured such that, when the excitation coil 122 is energized, the electromagnet unit can be electromagnetically coupled to the magnetic component 131 to generate an axial force acting on the moving component 13.
[0036] Specifically, the magnetically levitated control rod drive mechanism 1 can be configured such that when current is applied to the excitation coil 122, the electromagnet unit generates an electromagnetic field, which couples with the magnetic component 131, thereby generating an axial electromagnetic driving force acting on the moving component 13 to drive the drive rod 132 of the moving component 13, along with the control rod, to move axially. By controlling the energizing current and timing of the excitation coil 122, an electromagnetic levitation force can also be generated radially, allowing the moving component 13 to maintain its axial position, thus enabling the drive mechanism to achieve magnetically levitated contactless operation. When the excitation coil 122 is de-energized, the drive rod 132 and control rod of the moving component 13 can fall freely under the action of gravity to achieve emergency rod drop. Compared with the stepped adjustment of the traditional step-type drive mechanism, the electromagnetic coupling drive method of this application provides continuous and controllable motion, which is more conducive to achieving fine adjustment.
[0037] See Figure 3 The magnetic levitation control rod drive mechanism 1 also includes a radial support component 14, which is fixed to the pressure-resistant housing component 11 and is used to keep the moving part 13 centered when it is eccentric. Specifically, when in a non-eccentric working condition (such as normal operation), the moving part 13 is in a radially centered position. When the moving part 13 is eccentric due to external disturbances or electromagnetic force fluctuations, the radial support component 14 can limit the radial offset of the moving part 13, so that the moving part 13 is still near the centered position, thereby reducing the contact between the moving part 13 and the outside and preventing the electromagnet unit of the stator component 12 and the pressure-resistant housing component 11 from being worn or bumped.
[0038] The magnetic levitation control rod drive mechanism 1 provided in this application generates axial force by energizing the excitation coil 122 to electromagnetically couple the electromagnet unit and the magnetic component 131. This electromagnetic coupling replaces the traditional mechanical engagement between the pawl and the drive rod groove to provide driving and holding forces. In short, this control rod drive mechanism enables magnetic levitation-based contactless operation, fundamentally eliminating frictional contact between the pawl teeth and the groove surface, thus solving the problems of mechanical wear, impact loads, and noise vibration. Furthermore, compared to traditional magnetic lifting (stepping) control rod drive mechanisms, this magnetic levitation control rod drive mechanism 1 can instantly generate electromagnetic force when the excitation coil 122 is energized. This reduces mechanical transmission backlash and transmission delay, facilitating rapid response and precise positioning adjustments. The radial support component 14, which restricts the movement component 13 to remain centered only through its annular (narrow band) area, effectively reduces contact between the movement component 13 and the outside, further ensuring the reliability of magnetic levitation-based contactless operation. As a result, the moving parts of the control rod drive mechanism are no longer limited by the mechanical wear life of the hook and the drive rod ring groove, and the service life and reliability are significantly improved.
[0039] Preferably, a plurality of radial support components 14 are provided at least at both ends of the stator component 12 in the axial direction to prevent the mover component 13 from tilting to one side in the axial direction, so as to make the centering effect more reliable.
[0040] See Figure 3 In some embodiments, a gap is provided between the radial support member 14 and the moving part 13. In other words, when the moving part 13 is in a non-eccentric working condition (such as normal operation), there is a gap between the moving part 13 and the radial support member 14, and the two do not contact each other. The moving part 13 is radially centered in the air gap under the action of the electromagnetic force of the stator member 12. Furthermore, the gap between the radial support member 14 and the moving part 13 is smaller than the gap between the electromagnet unit and the magnetic member 131, so as to ensure that the radial support member 14 can contact the moving part 13 before the electromagnet unit, etc., avoiding contact damage between the electromagnet unit of the stator member 12 and the moving part 13, and improving operational reliability.
[0041] See Figure 4 , Figure 5 In some embodiments, the radial support component 14 includes a slip ring and / or a magnetic bearing.
[0042] A slip ring is a ring-shaped mechanical support component that limits the radial offset of the mover component 13 by contacting it. For example, under normal operating conditions, the slip ring maintains a gap with the mover component 13 without contact. Only under eccentric operating conditions does the slip ring contact the mover component 13 to keep it centered and protect other components such as the electromagnet unit. The slip ring can be designed to be wear-resistant, for example, made of wear-resistant alloy or with a wear-resistant coating, and is not limited to this.
[0043] Magnetic levitation bearings utilize magnetic force to achieve non-contact radial support for the moving part 13. Using magnetic levitation bearings helps to reduce mechanical contact between the moving part 13 and the outside.
[0044] See Figure 2 , Figure 4 , Figure 5 In some embodiments, the surfaces of the mover component 13 and / or the stator component 12 are covered with shielding sleeves to isolate the coolant and shield radiation. The shielding sleeves can be made of corrosion-resistant and radiation-resistant materials. For example, the shielding sleeves can be made of Hastelloy and / or nickel alloy materials, with a wall thickness of no more than 2 mm, to minimize the wall thickness while meeting pressure-resistant sealing requirements, thereby reducing the effective air gap between the stator component 12 and the mover component 13, reducing magnetic circuit reluctance, and increasing electromagnetic density.
[0045] Specifically, the surface of the mover component 13 is covered with a mover shielding sleeve 133 to isolate the coolant from direct contact with the magnetic component 131, preventing demagnetization and corrosion of the magnetic component 131. The two ends of the mover shielding sleeve 133 can be sealed to the rod body of the drive rod 132 using methods such as laser welding. After welding, a rolling process can be used to ensure a tight fit between the mover shielding sleeve 133 and the magnetic component 131, eliminating assembly gaps and ensuring the continuity of magnetic circuit conduction. For the stator component 12, which is fixed inside the pressure-resistant housing component 11 (i.e., inside the stator mounting housing 112), the surface of the stator component 12 is also covered with a shielding sleeve, including an inner shielding sleeve 123 on the inner surface and / or an outer shielding sleeve 124 on the outer surface, to isolate the coolant from direct contact with the iron core 121 and the excitation coil 122, preventing damage to the coil insulation and corrosion of the iron core. However, if the stator component 12 is fixed to the outside of the pressure-resistant housing component 11, the stator component 12 does not need to be shielded if it does not come into contact with the coolant, and this is not a limitation.
[0046] Furthermore, the air gap between the stator component 12 and the mover component 13 consists only of the mechanical clearance and the wall thickness of the shielding sleeve. For example, when both the mover component 13 and the stator component 12 are equipped with shielding sleeves, the air gap is composed of the mechanical clearance and the wall thickness of the shielding sleeves of the mover and stator, in order to ensure that the air gap is minimized, the magnetic reluctance of the magnetic circuit is reduced, and the electromagnetic density and levitation stiffness are improved. Here, "mechanical clearance" refers to the distance reserved between two physical surfaces to ensure that no mechanical contact occurs during operation.
[0047] See Figure 5 In some embodiments, the magnetic component 131 includes a permanent magnet 1311, such as a samarium cobalt permanent magnet. The samarium cobalt permanent magnet is a high-temperature resistant permanent magnet material, capable of withstanding the high-temperature environment of approximately 250°C within the reactor, which helps ensure operational reliability.
[0048] Further, see Figure 5 In some embodiments, the magnetic component 131 includes permanent magnets 1311 and soft magnets 1312 alternately stacked along the axial direction. The permanent magnets 1311 are, for example, samarium cobalt permanent magnets. The soft magnets 1312 are, for example, formed by axially stacking multiple soft magnetic sheets (such as silicon steel sheets). This design can significantly reduce the amount of samarium cobalt permanent magnets used while maintaining magnetic circuit efficiency, thus reducing material costs.
[0049] Preferably, the outer diameter and inner diameter of the permanent magnet 1311 and the soft magnet 1312 are consistent, and the outer diameter is the same as the inner diameter of the mover shield 133, so as to ensure that there is no structural break between the magnetic component 131 and the mover shield 133, and the magnetic circuit is continuously conducted along the permanent magnet 1311, the soft magnet 1312 and the mover shield 133, without any increase in magnetic resistance caused by abrupt changes in air gap or cross-section.
[0050] Optionally, the permanent magnet 1311 can be configured as circumferentially distributed arc-shaped permanent magnet blocks, with each arc-shaped permanent magnet block being embedded in a circumferential positioning groove between adjacent soft magnets 1312. The processing and manufacturing process of the arc-shaped permanent magnet blocks is simpler than that of the integral ring permanent magnet.
[0051] In other embodiments, the permanent magnet 1311 is monolithic, that is, the magnetic component 131 is composed of a single continuous samarium cobalt permanent magnet ring, without soft magnetic structures such as silicon steel sheets, which simplifies the assembly process.
[0052] See Figure 4 In some embodiments, the core 121 integrates a permanent magnet, while the magnetic component 131 includes a soft magnet 1312. In this configuration, the permanent magnet moves from the mover side to the stator side, and the permanent magnet on the stator side generates a basic levitation magnetic field. The excitation of the excitation coil 122 is used to adjust the axial force. The magnetic component 131 on the mover side consists only of a stacked structure of soft magnets 1312 and does not contain a permanent magnet. This simplifies the structure of the mover component 13 and facilitates assembly.
[0053] See Figure 1 In some embodiments, the pressure vessel component 11 includes, from top to bottom, a rod travel housing 111, a stator mounting housing 112, and a reactor top penetration 113, the inner cavity of which communicates with the reactor pressure vessel to meet the primary circuit pressure boundary integrity requirements. The rod travel housing 111 is used to drive the rod 132 upward through the space, the stator mounting housing 112 provides the mounting position for the stator component 12, and the reactor top penetration 113 passes through the top cover of the reactor pressure vessel. Generally, the pressure vessel component 11 also includes an extension housing 114 extending into the reactor pressure vessel, which can provide guidance for the rotor component 13, etc. The stator component 12 can be fixed inside or outside the stator mounting housing 112, without limitation.
[0054] Specifically, when the stator component 12 is fixed inside the stator mounting housing 112, the stator component 12 is within the pressure boundary and in the same sealed space as the primary coolant. In this case, the stator component 12 needs to be equipped with a shielding sleeve, and the stator mounting housing 112 needs to be equipped with an electrical penetration 115. The electrical cables for the excitation coil 122 pass through the pressure-resistant housing component 11 and are led out to the control cabinet. The electrical penetration 115 adopts a pressure-resistant and sealed structure. When the stator component 12 is fixed outside the stator mounting housing 112, the stator component 12 is outside the pressure boundary and does not contact the coolant. Therefore, there is no need to install an electrical penetration, which reduces the wiring difficulty. The structure and installation process of the top penetration 113 can be consistent with the traditional form without adapting the opening size of the pressure vessel top cover.
[0055] Preferably, the external dimensions and mounting interface of the drive rod 132 can be consistent with the drive rod of the existing magnetic lifting control rod drive mechanism, so that there is no need to make adaptive modifications to the opening size of the pressure vessel top cover, and direct replacement can be achieved, which improves the feasibility of engineering applications.
[0056] Preferably, the rod travel shell 111, the stator mounting shell 112, and the reactor top penetration 113 are made of nuclear-grade austenitic stainless steel. Austenitic stainless steel has excellent corrosion resistance, good processing and welding performance, and nuclear-grade material certification maturity, which can meet the integrity requirements of the primary circuit pressure boundary for high temperature, high pressure, and radiation resistance under normal reactor operation and accident conditions.
[0057] Preferably, the pressure-resistant shell component 11 is further provided with a heat insulation sleeve 16, which is located below the stator component 12 and is used to block the heat conduction path and provide guidance for the mover component 13.
[0058] Preferably, the magnetic levitation control rod drive mechanism 1 further includes a rod position detector 15, which is located on the outside of the rod stroke housing 111. It adopts a non-contact electromagnetic induction sensor array structure and arranges multiple sets of detection coils along the axial direction to detect the axial displacement of the moving part 13 in real time, thereby realizing real-time monitoring of the position of the control rod.
[0059] Preferably, the excitation coil 122 is supplied with a three-phase symmetrical current to form a synchronous speed translation magnetic field. By independently controlling the energizing current, energizing sequence, and current direction of the excitation coil 122, a controllable axial electromagnetic levitation force or driving force is generated between the stator component 12 and the mover component 13, thereby achieving the levitation, uniform lifting, or lowering of the drive rod 132. When the excitation coil 122 is de-energized, the drive rod 132 lowers under the action of gravity. The excitation coil 122 of the stator component 12 is energized as needed during adjustment operations, and the excitation current can be reduced to maintain levitation when maintaining the position, resulting in lower energy consumption than the magnetic yoke coil of a traditional drive mechanism.
[0060] This application also provides a magnetically levitated control rod driving method to drive the control rod through the magnetically levitated control rod driving mechanism 1 provided in this application. The driving method includes: The system provides a pressure-resistant housing component 11, a stator component 12, and a mover component 13. The stator component 12 is fixed to the pressure-resistant housing component 11 and includes multiple electromagnet units arranged axially. Each electromagnet unit includes an iron core 121 and an excitation coil 122 wound around the iron core 121. The mover component 13 includes a magnetic component 131 and a drive rod 132 connected to each other. The mover component 13 is movably disposed inside the pressure-resistant housing component 11 axially. An air gap is provided between the stator component 12 and the mover component 13. The magnetic levitation control rod drive mechanism 1 also includes a radial support component 14, which is fixed to the pressure-resistant housing component 11. A current is supplied to the excitation coil 122 to electromagnetically couple the electromagnet unit with the magnetic component 131, thereby generating an axial force acting on the moving component 13. By controlling the on / off state of the excitation coil 122 of different electromagnet units, as well as the current and timing, the magnitude and direction of the axial force can be adjusted to achieve axial movement adjustment or position maintenance of the drive rod 132. In eccentric operation, the moving part 13 is kept centered by the radial support part 14.
[0061] Generally, the magnetic levitation control rod driving method also includes: when the excitation coil 122 is de-energized, the drive rod 132 falls under its own gravity to achieve the rod dropping.
[0062] In summary, the beneficial technical effects of this application include, but are not limited to, at least one of the following: Compared to the traditional magnetic lifting (stepping) control rod drive mechanism described above, the magnetic levitation control rod drive mechanism provided in this application generates axial force by electromagnetically coupling the electromagnet unit and magnetic components through the energization of the excitation coil. This electromagnetic coupling replaces the traditional mechanical engagement between the pawl and the drive rod annular groove to provide driving and holding forces, fundamentally eliminating frictional contact between the pawl and the drive rod. This effectively avoids the mechanical wear, impact loads, and noise and vibration problems associated with traditional magnetic lifting (stepping) control rod drive mechanisms. Furthermore, the electromagnetic coupling method allows for the instantaneous generation of electromagnetic force when the excitation coil is energized, reducing mechanical transmission backlash and transmission delay, thus facilitating rapid response and precise positioning adjustment. The axial force of the electromagnet unit can be continuously adjusted through the excitation current, resulting in higher position control accuracy of the drive rod compared to traditional stepping mechanisms, which is beneficial for achieving precise adjustment of reactor power. The radial support component is set up to keep the moving part centered under eccentric conditions, avoiding direct contact between the moving part and the electromagnet unit of the stator component, thus further ensuring the reliability of the magnetic levitation contactless operation. As a result, the magnetic levitation control rod drive mechanism provided in this application significantly reduces the mechanical wear of the control rod drive mechanism, which is conducive to improving operational reliability and extending service life.
[0063] While this application discloses preferred embodiments as described above, it is not intended to limit the scope of this application. Any changes and modifications can be made by those skilled in the art without departing from the spirit and scope of this application. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application, without departing from the content of the technical solution of this application, fall within the protection scope defined by the claims of this application.
Claims
1. A magnetically levitated control rod drive mechanism, characterized in that, It includes pressure housing components, stator components, and rotor components; among which, The stator component is fixed to the pressure-resistant housing component. The stator component includes a plurality of electromagnet units arranged along the axial direction. Each electromagnet unit includes an iron core and an excitation coil wound around the iron core. The moving part includes a magnetic component and a drive rod connected together, and the moving part is axially movably disposed inside the pressure-resistant shell component; An air gap is provided between the stator component and the moving component. The magnetic levitation control rod drive mechanism is configured such that, when the excitation coil is energized, the electromagnet unit can be electromagnetically coupled with the magnetic component to generate an axial force acting on the moving component. The magnetic levitation control rod drive mechanism also includes a radial support component, which is fixed to the pressure-resistant shell component and is used to keep the moving part centered under eccentric conditions.
2. The magnetic levitation control rod drive mechanism according to claim 1, characterized in that, A gap is provided between the radial support component and the moving part, and the gap between the radial support component and the moving part is smaller than the gap between the electromagnet unit and the magnetic component.
3. The magnetic levitation control rod drive mechanism according to claim 1, characterized in that, The radial support component includes a slip ring and / or a magnetic bearing.
4. The magnetic levitation control rod drive mechanism according to claim 1, characterized in that, The surfaces of the moving part and / or the stator part are covered with shielding sleeves, which are used to isolate coolant and shield radiation.
5. The magnetic levitation control rod drive mechanism according to claim 4, characterized in that, The air gap consists only of the mechanical clearance and the wall thickness of the shielding sleeve.
6. The magnetic levitation control rod drive mechanism according to claim 1, characterized in that, The magnetic component includes a permanent magnet.
7. The magnetic levitation control rod drive mechanism according to claim 6, characterized in that, The magnetic component comprises samarium cobalt permanent magnets and soft magnets stacked alternately along the axial direction.
8. The magnetic levitation control rod drive mechanism according to claim 1, characterized in that, The iron core integrates a permanent magnet, and the magnetic components include soft magnets.
9. The magnetically levitated control rod drive mechanism according to claim 1, characterized in that, The pressure vessel component includes a rod travel shell, a stator mounting shell, and a top penetration member arranged from top to bottom, and its inner cavity communicates with the reactor pressure vessel; the stator component is fixed inside or outside the stator mounting shell, the rotor component is suspended in the air gap, and the top penetration member is used to pass through the reactor pressure vessel.
10. A method for driving a magnetically levitated control rod, characterized in that, The method of using a magnetically levitated control rod drive mechanism as described in any one of claims 1 to 8 to drive a control rod includes: A current is passed through the excitation coil to electromagnetically couple the electromagnet unit with the magnetic component, thereby generating an axial force acting on the moving part. By adjusting the axial force, the drive rod can be moved axially or kept in position. In eccentric operation, the radial support component keeps the moving part centered.