Nuclear reactor control rod position measuring device and method

Abstract

The invention provides a rod position measuring device and method for a nuclear reactor control rod, and the device comprises a control rod drive assembly which comprises a guide cylinder and a control rod drive rod in the guide cylinder, and the control rod drive rod moves in the axial direction of the guide cylinder; the measuring assembly comprises the series micro-motion detection element arranged on the inner side of the guide cylinder and a control module electrically connected with the series micro-motion detection element, and the series micro-motion detection element comprises two switch elements distributed in the motion direction of the control rod drive rod; and the control module is configured to judge the motion direction of the control rod according to the triggering sequence of the two switch elements and judge the current rod position according to the triggering times. According to the method, the rod position measurement requirement can be met without greatly modifying and adjusting the control rod driving rod; according to the measurement scheme, the rod position measurement precision of the control rod can reach + / -1 step and is greatly improved compared with inductance type measurement precision.

Description

Technical Field

[0001] This invention pertains to nuclear reactor control systems, specifically relating to a device and method for measuring the position of nuclear reactor control rods. Background Technology

[0002] In nuclear power plants, control rods are crucial devices for regulating reactor power and enabling emergency shutdowns, while the control rod position measurement system is a key component ensuring the safe operation of the nuclear reactor. Accurate measurement of the control rod positions is of paramount importance for reactor safety, power control, and reactivity management. Currently, nuclear reactor control rod position measurement technologies primarily include methods based on electromagnetic induction and methods based on rotation angle measurement.

[0003] However, existing control rod position measurement methods based on electromagnetic induction have some significant drawbacks. First, the measurement resolution is limited by the physical spacing of the coils, typically achieving only ±8 or ±4 steps of accuracy, which is insufficient for high-precision rod position measurement. Second, the series-connected coil structure carries the risk of single-point failure; a failure in any coil can lead to the failure of the entire measurement system. Furthermore, this method requires specialized power supply cabinets and complex electromagnetic coil signal processing cabinets, increasing system complexity, cost, and technical requirements.

[0004] The method of measuring the control rod position based on rotation angle also has significant shortcomings. The rod position measurement relies on precise control of the relative motion between components, especially ensuring the accuracy of the traction rope's winding on the hub. When the traction rope overlaps or has gaps while winding on the hub, it will cause a large deviation in the control rod position measurement, affecting the accuracy and reliability of the measurement.

[0005] Therefore, existing nuclear reactor control rod position measurement technologies suffer from problems such as limited measurement accuracy, high system complexity, insufficient reliability, and high cost. There is an urgent need to develop a nuclear reactor control rod position measurement device that can improve the accuracy of rod position measurement, reduce system complexity, improve measurement reliability, simplify supporting equipment, and enhance system economy. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a control rod position measurement device and method for nuclear reactors, so as to solve the problems of limited measurement resolution, high risk of single-point failure, and need for special equipment in the existing control rod position measurement method based on the electromagnetic induction principle, as well as the problems of the rotation angle measurement scheme relying on fine control and being prone to deviation. The invention aims to improve the rod position measurement accuracy, reduce system complexity, improve reliability, simplify supporting equipment, and improve economy.

[0007] To achieve the above and other related objectives, the present invention provides a nuclear reactor control rod position measurement device, comprising:

[0008] A control rod drive assembly includes a guide cylinder and a control rod drive rod inside the guide cylinder, the control rod drive rod being axially movable along the guide cylinder;

[0009] The measuring component includes a series micro-motion detection element arranged inside the guide cylinder and a control module electrically connected to the series micro-motion detection element. The series micro-motion detection element includes two switching elements distributed along the movement direction of the control rod drive rod. The control module is configured to determine the movement direction of the control rod according to the triggering sequence of the two switching elements and to determine the current rod position according to the number of triggers.

[0010] In one embodiment of the present invention, the control rod drive rod is provided with a plurality of annular protrusions spaced apart along its axial direction, and the series micro-motion detection element is arranged between two adjacent annular protrusions and close to the bottom of the guide cylinder.

[0011] In one embodiment of the present invention, the measuring assembly includes a plurality of serially connected micro-motion detection elements, which are arranged at circumferential intervals along the guide cylinder.

[0012] In one embodiment of the present invention, the switching element includes a first switch and a second switch, wherein the first switch is located above the second switch;

[0013] When the first switch is triggered before the second switch, the control rod moves downward along the axial direction;

[0014] When the second switch is triggered before the first switch, the control rod moves upward along the axis.

[0015] In one embodiment of the present invention, the control module includes:

[0016] A circuit timing detection unit, which is electrically connected to the series micro-motion detection element, is used to detect the triggering sequence of the first switch and the second switch;

[0017] A motion direction recognition unit is electrically connected to the circuit timing detection unit, and identifies the motion direction of the control rod according to the triggering sequence of the first switch and the second switch.

[0018] In one embodiment of the present invention, the control module further includes a motion direction voting unit, and each of the series micro-motion detection elements is connected to a circuit timing detection unit and a motion direction recognition unit. The motion direction voting unit determines the motion direction of the control rod based on the recognition result of the motion direction recognition unit corresponding to each of the series micro-motion detection elements.

[0019] In one embodiment of the present invention, the control module further includes a rod position calculation unit that accumulates and counts the position of the control rod based on the direction of movement of the control rod and the number of times the series micro-motion detection element is triggered.

[0020] In one embodiment of the present invention, a rod position limit detection element is further included. The rod position limit detection element is electrically connected to the control module and is disposed at a position near the top of the guide cylinder. When the rod position limit detection element is triggered, the control rod is at the maximum rod position height.

[0021] In one embodiment of the present invention, the control module further includes a fault detection unit, which is used to compare and analyze the triggering result of the rod position limit detection element with the predefined maximum rod position height. When the rod position limit detection element is triggered, the rod position value is equal to the maximum rod position height, which indicates that the system is normal.

[0022] This invention also proposes a method for measuring the position of control rods in a nuclear reactor, comprising:

[0023] The circuit timing detection unit receives the trigger signals of the first and second switches in each series micro-motion detection element;

[0024] The motion direction recognition unit identifies the motion direction of the control rod based on the triggering timing of the first switch and the second switch;

[0025] The motion direction voting unit determines the motion direction of the control rod by voting on the motion direction identified by each motion direction identification unit.

[0026] The rod position calculation unit accumulates the rod position based on the direction of the control rod's movement and the number of times the series micro-motion detection element is triggered. When the control rod moves upward by 1 step, the rod position is incremented by 1; when the control rod moves downward by 1 step, the rod position is decremented by 1.

[0027] In one embodiment of the present invention, the method further includes: comparing and analyzing the triggering result of the rod position limit detection element with a predefined maximum rod position height; when the rod position limit detection element is triggered, if the rod position value is equal to the maximum rod position height, it indicates that the system is normal; otherwise, a fault signal is sent.

[0028] The beneficial effects of this invention are as follows: This invention can meet the rod position measurement requirements without making significant modifications or adjustments to the control rod drive lever; compared with the inductive measurement principle, this invention uses a simpler and more reliable series micro-motion circuit detection element, which can measure the control rod's movement direction and number of steps based on the micro-motion circuit timing; the control rod position measurement accuracy of this measurement scheme can reach ±1 step, a significant improvement over the inductive measurement accuracy; compared with the inductive measurement principle, it eliminates the need for a large number of coils and their arrangement, reducing system complexity, and eliminates the need for a dedicated high-quality power supply and induced electromotive force measurement and analysis device, simplifying the overall system's power load and equipment configuration, thus improving system economy. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the control rod upward movement of the nuclear reactor control rod position measuring device of the present invention.

[0031] Figure 2 This is a cross-sectional view of the nuclear reactor control rod position measuring device of the present invention.

[0032] Figure 3 This is a schematic diagram of the control module in the nuclear reactor control rod position measuring device of the present invention.

[0033] Figure 4 This is a schematic diagram of the structure of the control rod downward movement of the nuclear reactor control rod position measuring device of the present invention.

[0034] Figure 5 This is a schematic diagram of the triggering timing of the downward movement of the control rod in the nuclear reactor control rod position measuring device of the present invention.

[0035] Figure 6 This is a schematic diagram of the structure of the control rod upward movement of the nuclear reactor control rod position measuring device of the present invention.

[0036] Figure 7 This is a schematic diagram of the triggering timing of the upward movement of the control rod in the nuclear reactor control rod position measuring device of the present invention. Detailed Implementation

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components relevant to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0039] Please see Figure 1 , Figure 2 and Figure 3 As shown, this invention proposes a control rod position measurement device and method for nuclear reactors to address the problems of limited measurement resolution, high risk of single-point failure, and the need for specialized equipment in existing control rod position measurement methods based on electromagnetic induction, as well as the problems of reliance on fine control and susceptibility to deviation in rotation angle measurement schemes. The invention aims to improve rod position measurement accuracy, reduce system complexity, improve reliability, simplify supporting equipment, and enhance economy. Specifically, the rod position measurement device includes a control rod drive assembly and a measurement assembly. The control rod drive assembly includes a guide cylinder 10 and a control rod drive rod 20 disposed within the guide cylinder 10, which moves axially along the guide cylinder 10. Multiple annular protrusions 21 are spaced apart along the axial direction of the control rod drive rod 20. These annular protrusions 21 trigger the measurement assembly during the movement of the control rod drive rod 20. The number and spacing of the annular protrusions 21 can be designed according to the required measurement accuracy to meet the requirements of the nuclear reactor control system for precise rod position measurement.

[0040] Please see Figure 1 , Figure 2 and Figure 3 As shown, in this embodiment, the measuring assembly includes a series micro-motion detection element 30 arranged inside the guide cylinder 10 and a control module electrically connected to the series micro-motion detection element 30. The series micro-motion detection element 30 includes two switching elements distributed along the movement direction of the control rod drive rod 20, namely a first switch 31 and a second switch 32, wherein the first switch 31 is located above the second switch 32. The series micro-motion detection element 30 is arranged between two adjacent annular protrusions 21 and close to the bottom of the guide cylinder 10, which ensures that the annular protrusions 21 can sequentially trigger the first switch 31 and the second switch 32 during movement, thereby achieving accurate monitoring of the movement state of the control rod and precise measurement of its position.

[0041] Please see Figure 1 , Figure 2 and Figure 3 As shown, in this embodiment, the measurement assembly includes multiple series-connected micro-motion detection elements 30, which are arranged at intervals along the circumference of the guide cylinder 10. In this embodiment, three series-connected micro-motion detection elements 30 are evenly distributed circumferentially inside the guide cylinder 10. This distribution method can improve the accuracy and reliability of the measurement, and at the same time, multi-point detection can effectively avoid the system risks caused by single-point failures, ensuring the safe and stable operation of the nuclear reactor control system.

[0042] Please see Figure 1 , Figure 2 and Figure 3 As shown, in this embodiment, the control module includes a circuit timing detection unit 41, a motion direction recognition unit 42, a motion direction voting unit 43, and a rod position calculation unit 44. The circuit timing detection unit 41 is electrically connected to the series micro-motion detection element 30, and is used to detect the triggering sequence of the first switch 31 and the second switch 32, and transmit the detected timing signal to the subsequent processing unit. The motion direction recognition unit 42 is electrically connected to the circuit timing detection unit 41, and identifies the control rod's motion direction according to the triggering sequence of the first switch 31 and the second switch 32, providing a directional basis for rod position calculation.

[0043] Please see Figure 4 and Figure 5 As shown, when the control rod moves from top to bottom, the annular protrusion 21 on the control rod drive lever 20 first triggers the first switch 31, and then triggers the second switch 32, forming a specific triggering sequence. Conversely, please refer to... Figure 6 and Figure 7 As shown, when the control rod moves from bottom to top, the annular protrusion 21 will first trigger the second switch 32, and then trigger the first switch 31, generating a trigger timing pattern different from the downward direction.

[0044] Figure 5 and Figure 7 The timing diagrams for contacts A and B are shown for different directions of control rod movement. For example... Figure 5 As shown, when the second switch 32 is triggered before the first switch 31, it indicates that the control rod moves upward along the axial direction; as Figure 7 As shown, when the first switch 31 is triggered before the second switch 32, it indicates that the control rod is moving downward along the axial direction. This direction determination mechanism based on the triggering sequence is simple and reliable, unaffected by the speed of the control rod, and can maintain a stable direction determination capability under various working conditions, ensuring the accuracy of rod position measurement.

[0045] Please see Figure 4 and Figure 5As shown, specifically, the first switch 31 and the second switch 32 arranged on each series micro-motion detection element 30 are micro-motion contact switch unit A and micro-motion contact switch unit B, respectively. When the control rod drives the rod downward, the circuit timing of the series micro-motion detection element 30 is that micro-motion contact switch unit A acts first, followed by micro-motion contact switch unit B. The circuit timing detection unit monitors the circuit timing of the series micro-motion detection elements and sends the circuit timing signal to the control rod movement direction recognition unit. The control rod movement direction recognition unit can determine that the control rod drives the rod downward by one step based on the circuit timing.

[0046] Please see Figure 6 and Figure 7 As shown, when the control rod drives the lever upward, the circuit timing of the series micro-motion detection element is that the micro-motion contact switch unit B acts first, followed by the micro-motion contact switch unit A. The circuit timing detection unit monitors the circuit timing of the series micro-motion detection element and sends the circuit timing signal to the control rod movement direction recognition unit. The control rod movement direction recognition unit can determine that the control rod drives the lever upward by 1 step based on the circuit timing.

[0047] It is understood that in this embodiment, more sets of redundant series micro-motion circuit detection elements can be used to improve system reliability. Different types of micro-motion contact switches can be used, such as normally open contacts and normally closed contacts; and different micro-motion circuit detection unit principles can be used, such as mechanical micro-motion switches, magnetic switches, Hall elements, reed switches and other different types of sensors.

[0048] Please see Figure 3 As shown, in this embodiment, each series micro-motion detection element 30 is connected to a circuit timing detection unit 41 and a motion direction recognition unit 42. The motion direction voting unit 43 determines the control rod motion direction based on the recognition result of the motion direction recognition unit corresponding to each series micro-motion detection element 30. This multi-detection and voting mechanism can effectively avoid misjudgments caused by the failure of a single detection element, greatly improving the reliability and safety of the system, and is particularly suitable for applications with extremely high safety requirements, such as nuclear reactors. For example, the motion direction voting unit 43 outputs the final control rod motion direction result after logically voting on the result of the motion direction recognition unit 42. For example, when three sets of redundant series micro-motion detection elements 30 are set, a "two out of three" voting logic can be used, that is, two or more identical signals determine the motion direction of the control rod.

[0049] Please see Figure 3As shown, in this embodiment, the rod position calculation unit 44 accumulates and counts the control rod position based on the control rod's movement direction and the number of times the series micro-motion detection element 30 is triggered. By recording the number of times the annular protrusion 21 on the control rod drive rod 20 triggers the series micro-motion detection element 30, and combining this with the movement direction, the current position of the control rod can be accurately calculated, providing precise position data support for the control and monitoring of the nuclear reactor. For example, the rod position when the control rod is at its lowest point is defined as the 0 rod position. The initial value of the control rod position in the rod position calculation unit 44 is 0. The rod position calculation unit 44 accumulates and counts the control rod position based on the result of the control rod movement direction voting unit. When the control rod moves upward by 1 step, the control rod position increases by 1 step; when the control rod moves downward by 1 step, the control rod position decreases by 1.

[0050] Please see Figure 1 and Figure 3 As shown, the nuclear reactor control rod position measuring device also includes a rod position limit detection element 51, which is electrically connected to the control module and is located near the top of the guide cylinder 10. When the rod position limit detection element 51 is triggered, it indicates that the control rod has reached its maximum position height. The system will record this state and perform corresponding processing to ensure that the control rod operates within a safe range.

[0051] Please see Figure 1 and Figure 3 As shown, the fault detection unit is used to compare and analyze the triggering result of the rod position limit detection element 51 with the predefined maximum rod position height. When the rod position limit detection element 51 is triggered, if the rod position value is equal to the maximum rod position height, it indicates that the system is normal; if there is an inconsistency, it indicates that the system may have a fault and needs maintenance or calibration. This self-diagnostic function greatly improves the safety and maintainability of the system. Specifically, when the control rod moves to the top, the rod position limit detection element 51 located at the top of the guide cylinder 10 is triggered, thereby interlocking the control rod drive structure to stop the rod lifting action. At the same time, the action signal of the rod position limit detection element 51 serves as the correction signal for the maximum rod position of the rod position calculation unit 44. If the rod position value of the rod position calculation unit 44 at this time is equal to the predefined maximum rod position height, it proves that the rod position measurement system is working normally; otherwise, the rod position measurement system has malfunctioned and a fault alarm needs to be issued.

[0052] In this embodiment, a rod position information communication unit is also provided to transmit control rod position information and fault alarm information to the relevant control system, such as the distributed control system (DCS) of a nuclear power plant or the reactor power control system.

[0053] This nuclear reactor control rod position measurement device detects the movement of the annular protrusion 21 on the control rod drive rod 20 using series micro-motion detection elements 30. It determines the direction of movement based on the trigger sequence and calculates the rod position based on the number of triggers, thus achieving precise measurement of the control rod position. Multiple circumferentially distributed series micro-motion detection elements 30 improve system reliability, while the rod position limit detection element and fault detection unit enhance system safety and self-diagnostic capabilities. This ensures the entire measurement system maintains stable and reliable performance even in the harsh operating environment of a nuclear reactor, providing crucial protection for the safe operation of the nuclear reactor.

[0054] Please see Figure 1 , Figure 2 and Figure 3 As shown, this embodiment provides a method for measuring the position of control rods in a nuclear reactor. This method is applied to the aforementioned nuclear reactor control rod position measuring device, which includes a guide cylinder 10. A control rod drive rod 20 is disposed within the guide cylinder 10, and an annular protrusion 21 is provided on the control rod drive rod 20. Three series-connected micro-motion detection elements 30 are evenly distributed circumferentially within the guide cylinder 10. Each series-connected micro-motion detection element 30 includes an upper first switch 31 and a lower second switch 32.

[0055] The method for measuring the position of control rods in a nuclear reactor includes the following steps:

[0056] The circuit timing detection unit 41 receives the trigger signals from the first switch 31 and the second switch 32 in each of the series micro-motion detection elements 30. For example... Figure 1 As shown, when the control rod moves from bottom to top, the annular protrusion 21 on the control rod drive lever 20 first contacts the second switch 32, and then contacts the first switch 31, generating a corresponding trigger signal; as Figure 4 As shown, when the control rod moves from top to bottom, the annular protrusion 21 first contacts the first switch 31, and then contacts the second switch 32, thus generating a corresponding trigger signal. The circuit timing detection unit 41 monitors these trigger signals in real time and records their timing information.

[0057] The motion direction recognition unit 42 identifies the motion direction of the control rod according to the triggering timing of the first switch 31 and the second switch 32. For example... Figure 2 As shown, when the control rod moves from bottom to top, the second switch 32 (contact B) is triggered first, followed by the first switch 31 (contact A). Through this specific triggering sequence, the motion direction recognition unit determines that the control rod is moving upwards; as... Figure 5 As shown, when the control rod moves from top to bottom, the first switch 31 (A contact) is triggered first, followed by the second switch 32 (B contact). Through this reverse triggering sequence, the motion direction recognition unit 42 determines that the control rod is moving downward.

[0058] The motion direction voting unit 43 determines the motion direction of the control rod by voting based on the identified motion direction corresponding to each motion direction identification unit 42. For example... Figure 3 As shown, three series-connected micro-motion detection elements 30 are evenly distributed circumferentially within the guide cylinder 10, each corresponding to a motion direction identification unit 42. The motion direction voting unit 43 collects the identification results from these three motion direction identification units and determines the actual motion direction of the control rod through a majority voting principle; that is, when the identification results of at least two motion direction identification units 42 are consistent, the result is determined as the actual motion direction of the control rod. This voting mechanism effectively improves the reliability of the system and avoids misjudgments caused by the failure of a single detection element.

[0059] The rod position calculation unit 44 accumulates the control rod position count based on the control rod's movement direction and the number of triggers of the series micro-motion detection element 30. When the control rod moves upward one step, the control rod position is incremented by 1; when the control rod moves downward one step, the control rod position is decremented by 1. The rod position calculation unit continuously tracks the position change of the control rod and updates the current position of the control rod in real time through accumulation or decrement operations. This counting method ensures the accuracy and real-time performance of the rod position measurement, providing important parameters for the safe operation of the nuclear reactor.

[0060] In addition, the method includes a rod position limit detection step: The triggering result of the rod position limit detection element 51 is compared with a predefined maximum rod position height. When the rod position limit detection element 51 is triggered, the rod position value equals the maximum rod position height, indicating that the system is normal; otherwise, a fault signal is sent. This step verifies the accuracy of the rod position measurement system by comparing the actually detected rod position limit signal with the system's preset maximum rod position height value. When the detected rod position limit matches the preset maximum rod position height, the system is confirmed to be working normally; if an inconsistency occurs, the system will immediately send a fault signal to remind operators to inspect and repair, ensuring the safe operation of the nuclear reactor.

[0061] Through the above steps, this nuclear reactor control rod position measurement method can accurately and reliably monitor the movement direction and position of the control rods, providing an important guarantee for the safe operation of the nuclear reactor.

[0062] This invention proposes a device and method for measuring the position of control rods in a nuclear reactor. It meets the requirements for rod position measurement without requiring significant modifications or adjustments to the control rod drive rods. Compared to inductive measurement, this invention employs a simpler and more reliable series micro-motion circuit detection element. The direction and number of movement steps of the control rod can be measured based on the timing of the micro-motion circuit. The control rod position measurement accuracy of this method can reach ±1 step, a significant improvement over inductive measurement. Compared to inductive measurement, it eliminates the need for numerous coils and their arrangement, reducing system complexity. Furthermore, it eliminates the need for a dedicated high-quality power supply and induced electromotive force measurement and analysis device, simplifying the overall system's power load and equipment configuration, thus improving system economy.

[0063] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A device for measuring the position of control rods in a nuclear reactor, characterized in that, include: A control rod drive assembly includes a guide cylinder and a control rod drive rod inside the guide cylinder, the control rod drive rod being axially movable along the guide cylinder; The measuring component includes a series micro-motion detection element arranged inside the guide cylinder and a control module electrically connected to the series micro-motion detection element. The series micro-motion detection element includes two switching elements distributed along the movement direction of the control rod drive rod. The control module is configured to determine the movement direction of the control rod according to the triggering sequence of the two switching elements and to determine the current rod position according to the number of triggers.

2. The nuclear reactor control rod position measuring device according to claim 1, characterized in that, The control rod drive rod has multiple annular protrusions spaced apart along its axial direction, and the series micro-motion detection element is arranged between two adjacent annular protrusions and close to the bottom of the guide cylinder.

3. The nuclear reactor control rod position measuring device according to claim 1, characterized in that, The measuring assembly includes multiple series micro-motion detection elements, which are arranged at circumferential intervals along the guide cylinder.

4. The nuclear reactor control rod position measuring device according to claim 3, characterized in that, The switching element includes a first switch and a second switch, with the first switch located above the second switch; When the first switch is triggered before the second switch, the control rod moves downward along the axial direction; When the second switch is triggered before the first switch, the control rod moves upward along the axis.

5. The nuclear reactor control rod position measuring device according to claim 4, characterized in that, The control module includes: A circuit timing detection unit, which is electrically connected to the series micro-motion detection element, is used to detect the triggering sequence of the first switch and the second switch; A motion direction recognition unit is electrically connected to the circuit timing detection unit, and identifies the motion direction of the control rod according to the triggering sequence of the first switch and the second switch.

6. The nuclear reactor control rod position measuring device according to claim 5, characterized in that, The control module further includes a motion direction voting unit. Each of the series micro-motion detection elements is connected to a circuit timing detection unit and a motion direction recognition unit. The motion direction voting unit determines the motion direction of the control rod based on the recognition result of the motion direction recognition unit corresponding to each of the series micro-motion detection elements.

7. The nuclear reactor control rod position measuring device according to claim 5, characterized in that, The control module also includes a rod position calculation unit that accumulates and counts the position of the control rod based on the direction of movement of the control rod and the number of times the series micro-motion detection element is triggered.

8. The nuclear reactor control rod position measuring device according to claim 7, characterized in that, It also includes a rod position limit detection element, which is electrically connected to the control module and is located near the top of the guide cylinder. When the rod position limit detection element is triggered, the control rod is at its maximum rod position height.

9. The nuclear reactor control rod position measuring device according to claim 8, characterized in that, The control module also includes a fault detection unit, which is used to compare and analyze the triggering result of the rod position limit detection element with the predefined maximum rod position height. When the rod position limit detection element is triggered, the rod position value is equal to the maximum rod position height, which indicates that the system is normal.

10. A method for measuring the position of control rods in a nuclear reactor, characterized in that, include: The circuit timing detection unit receives the trigger signals of the first and second switches in each series micro-motion detection element; The motion direction recognition unit identifies the motion direction of the control rod based on the triggering timing of the first switch and the second switch; The motion direction voting unit determines the motion direction of the control rod by voting on the motion direction identified by each motion direction identification unit. The rod position calculation unit accumulates the rod position based on the direction of the control rod's movement and the number of times the series micro-motion detection element is triggered. When the control rod moves upward by 1 step, the rod position is incremented by 1; when the control rod moves downward by 1 step, the rod position is decremented by 1.

11. The method for measuring the position of control rods in a nuclear reactor according to claim 10, characterized in that, The method further includes: comparing and analyzing the triggering result of the rod position limit detection element with the predefined maximum rod position height. When the rod position limit detection element is triggered, if the rod position value is equal to the maximum rod position height, it indicates that the system is normal; otherwise, a fault signal is sent.

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