Method for determining rod falling time of control rod

Abstract

The embodiment of the invention relates to the technical field of nuclear reactor design, in particular to a method for determining rod falling time of a control rod, which is applied to a fast neutron reactor and comprises the following steps: acquiring a shutdown signal of the fast neutron reactor and determining a moment corresponding to the shutdown signal as a first moment; a driving signal of the driving device is obtained, and when the driving signal indicates that the driving parameter of the driving device is lower than a preset parameter threshold value, the moment corresponding to the driving signal is determined as a second moment; acquiring a rod position measurement signal of the control rod, and determining the moment corresponding to the rod position measurement signal as a third moment when the rod position measurement signal indicates that the control rod reaches a rod position corresponding to the shutdown depth requirement; and determining the rod falling time of the control rod according to the first moment, the second moment and the third moment. According to the method provided by the embodiment of the invention, the rod falling time of the control rod is determined according to the obtained first moment, second moment and third moment, the participation of operators and operation personnel is not needed, and the measurement efficiency is relatively high.

Description

Technical Field

[0001] The present application relates to the technical field of nuclear reactor design, and in particular to a method for determining a control rod drop time. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] A nuclear reactor is a device that realizes the utilization of nuclear energy. It includes a variety of regulatory systems to maintain the safe operation of the reactor. When an abnormal situation that some regulatory systems cannot cope with is detected, an emergency shutdown can be triggered by cutting off the power supply to the control rod drive device.

[0004] After triggering the emergency shutdown, the control rod drive device can drive the control rod into the core as quickly as possible within the specified time, while ensuring that the negative reactivity introduced by the control rod can meet the shutdown depth requirements to ensure the safety of the reactor. However, since the current method for determining the control rod drop time is not ideal, it is not conducive to the operator to accurately and conveniently obtain the rod drop time that matches the operation technical specifications. Summary of the invention

[0005] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] An embodiment of the present application provides a method for determining a control rod drop time, which is applied to a fast neutron reactor. The fast neutron reactor includes a driving device for driving a control rod, and includes the following steps:

[0007] S1, obtaining a shutdown signal of a fast neutron reactor and determining a time corresponding to the shutdown signal as a first time;

[0008] S2, obtaining a driving signal of the driving device, and when the driving signal indicates that a driving parameter of the driving device is lower than a preset parameter threshold, determining a moment corresponding to the driving signal as a second moment;

[0009] S3, obtaining a rod position measurement signal of the control rod, and when the rod position measurement signal indicates that the control rod has reached a rod position corresponding to the shutdown depth requirement, determining the time corresponding to the rod position measurement signal as the third time;

[0010] S4. Determine the control rod drop time according to the first moment, the second moment and the third moment.

[0011] The method provided in the embodiment of the present application can determine the rod drop time of the control rod according to the first moment corresponding to the shutdown signal, the second moment corresponding to when the driving parameter of the driving device is lower than the preset parameter threshold, and the third moment corresponding to when the control rod reaches the rod position corresponding to the shutdown depth requirement. It does not require the participation of operators and operating personnel, can ensure the measurement efficiency of the rod drop time, and is also conducive to improving the degree of automation of measuring the rod drop time.

[0012] These and other advantages of the present application will become more apparent through the following detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to further illustrate the above and other advantages and features of the present application, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings together with the following detailed description are included in this specification and form a part of this specification. Elements with the same function and structure are represented by the same reference numerals. It should be understood that these drawings only describe typical examples of the present application and should not be regarded as limiting the scope of the present application.

[0014] Figure 1 is a flow chart of a method for determining a control rod drop time according to an embodiment of the present application;

[0015] Figure 2 It is a curve showing the changes of various signals over time obtained by measuring the measuring device according to the embodiment of the present application.

[0016] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding. DETAILED DESCRIPTION

[0017] Exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the content of this application.

[0018] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0019] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should have the common meanings understood by persons with ordinary skills in the field to which this application belongs.

[0020] In the description of the embodiments of the present application, “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0021] The inventor of the present application has found that, due to the great difference between the structure of the control rod drive device of the fast neutron reactor and the structure of the control rod drive device of other types of reactors (such as pressurized water reactors), it is impossible to use the rod drop time measurement method in the related art to measure the rod drop time of the control rod. For example, the rod drop time of the control rod is determined by measuring and processing the magnitude of the induced voltage of the rod position measurement coil of the control rod drive device. In addition, the rod drop time measurement method in the related art requires the operator and operating personnel to participate in the calculation during the implementation process, and the measurement efficiency and measurement accuracy are low.

[0022] In view of the above technical problems, an embodiment of the present application provides a method for determining the control rod drop time, which is applied to a fast neutron reactor. A fast neutron reactor may include a driving device for driving the control rod. Figure 1 As shown, the method may include the following steps S1 to S4.

[0023] S1. Obtain a shutdown signal of a fast neutron reactor and determine a time corresponding to the shutdown signal as a first time.

[0024] S2. Acquire a driving signal of the driving device, and when the driving signal indicates that a driving parameter of the driving device is lower than a preset parameter threshold, determine a moment corresponding to the driving signal as a second moment.

[0025] S3. Obtain a rod position measurement signal of the control rod, and when the rod position measurement signal indicates that the control rod has reached a rod position corresponding to the shutdown depth requirement, determine the time corresponding to the rod position measurement signal as the third time.

[0026] S4. Determine the control rod drop time according to the first moment, the second moment and the third moment.

[0027] The method provided in the embodiment of the present application can determine the rod drop time of the control rod according to the first moment corresponding to the shutdown signal, the second moment corresponding to when the driving parameter of the driving device is lower than the preset parameter threshold, and the third moment corresponding to when the control rod reaches the rod position corresponding to the shutdown depth requirement. It does not require the participation of operators and operating personnel, can ensure the measurement efficiency of the rod drop time, and is also conducive to improving the degree of automation of measuring the rod drop time.

[0028] In some embodiments, the fast neutron reactor may include a reactor protection system, a rod control and rod position indication system. The reactor protection system may include a shutdown circuit breaker. The shutdown circuit breaker may be used to disconnect the power supply of the control rod drive device to achieve a safe shutdown of the fast neutron reactor. The rod control and rod position indication system may include a control rod drive device and a measuring device. The control rod drive device may be used for driving control of the drive mechanism to achieve lifting, lowering, and holding of the control rod. The measuring device may be used to obtain a position signal of the control rod, including but not limited to the driving signal and the rod position measurement signal in the embodiments of the present application.

[0029] In some embodiments, in step S1, a shutdown signal of the shutdown circuit breaker may be introduced into the measuring device through hard wiring, so that the shutdown signal is acquired by the measuring device. The shutdown signal may be a trip signal of the shutdown circuit breaker. When the measuring device acquires the shutdown signal, the moment when the shutdown signal is currently acquired may be recorded as the first moment t0.

[0030] In some embodiments, in step S2, the driving signal of the driving device can be introduced into the measuring device through hard wiring, so that the measuring device can obtain the driving signal. When the driving signal indicates that the driving parameter of the driving device is lower than the preset parameter threshold, the measuring device can determine the moment corresponding to the current driving signal as the second moment t1. The preset parameter threshold can be set based on experience.

[0031] In some embodiments, the fast neutron reactor may further include a rod position measuring device for measuring the rod position of the control rod. When the rod position measurement signal indicates that the control rod has reached a rod position corresponding to the shutdown depth requirement, the measuring device may determine the time corresponding to the current rod position measurement signal as the third time t2.

[0032] In some embodiments, the rod position measurement device may include an angle sensor. The angle sensor is used to detect the continuous operating position of the control rod and convert the linear motion of the control rod drive device into an angle signal through a transmission device. In step S3, the angle signal can be used as a rod position measurement signal.

[0033] In some embodiments, the rod position measurement device may include an inductive sensor. The inductive sensor is used to detect the discrete operating position of the control rod to obtain a position signal of the control rod. In step S3, the position signal may be used as a rod position measurement signal.

[0034] In the embodiment of the present application, the first moment, the second moment and the third moment are measured by a measuring device, and then the rod drop time of the control rod is determined, which can improve the measurement accuracy of the rod drop time.

[0035] In some embodiments, after step S4, the method provided by the embodiments of the present application may further include: determining a rod drop curve of the control rod according to the shutdown signal and the first moment obtained in step S1, the drive signal and the second moment obtained in step S2, the rod position measurement signal and the third moment obtained in step S3, and the rod drop time determined in step S4.

[0036] In some embodiments, Figure 2 As shown, the method provided in the embodiment of the present application can also be used to obtain a control rod drop curve, that is, a curve of multiple signals changing with time. This curve can assist in troubleshooting problems when the rod drop time requirement is not met during subsequent operation.

[0037] In some embodiments, step S4 may include: S41, determining a driving delay time of the driving device based on the first moment and the second moment; S42, determining a falling time of the control rod based on the second moment and the third moment; S43, determining a rod dropping time based on the driving delay time and the falling time.

[0038] The method provided in the embodiment of the present application can determine the rod drop time of the control rod according to the drive delay time and the drop time, which can not only reduce the error of the determined rod drop time but also eliminate the need for operators and operating personnel to perform manual calculations, thereby further improving the efficiency of determining the rod drop time of the control rod.

[0039] In some embodiments, in step S41, the driving delay time T1 of the driving device can be determined by calculating the difference between the first time t0 and the second time t1, that is, T1 = t1 - t0.

[0040] In some embodiments, in step S42, the falling time T2 of the control rod can be determined by calculating the difference between the second time t1 and the third time t2, that is, T2=t2-t1.

[0041] In some embodiments, in step S43, the rod drop time T can be determined by calculating the sum of the driving delay time T1 and the drop time T2. 总 , that is, T 总 =T1+T2.

[0042] In such an embodiment, by respectively determining the driving delay time T1 of the driving device and the falling time T2 of the control rod, it is possible to respectively determine whether each time period meets the corresponding index requirements, thereby ensuring the accuracy of the rod falling time determined based on the driving delay time T1 and the falling time T2. For example, the driving delay time T1 of the driving device satisfies T1<100ms; for a device whose driving device includes an electromagnetic clutch, the falling time T2 of the control rod satisfies T2<1.4s; for a device whose driving device includes a motor, the falling time T2 of the control rod satisfies T2<5.9s.

[0043] In some embodiments, the driving device may include a motor, and step S2 may include: S21, obtaining a current signal of the motor; S22, converting the current signal into a first standard signal, wherein the driving signal may include the first standard signal; S23, when the first standard signal indicates that the current of the motor is lower than a preset current threshold, determining the moment corresponding to the first standard signal as the second moment, wherein the preset parameter threshold includes a preset current threshold.

[0044] The method provided in the embodiment of the present application converts the current signal of the motor into a first standard signal, and then when the first standard signal indicates that the current of the motor is lower than a preset current threshold, determines the moment corresponding to the first standard signal as the second moment. This can ensure higher reliability while ensuring a faster current signal transmission speed, which is beneficial to ensuring the reliability of the rod drop time finally obtained.

[0045] In some embodiments, the motor of the driving device can be controlled by current closure. The driving device can include a current sensor for detecting the motor winding current to obtain a current signal. Exemplarily, the current sensor can be a Hall sensor.

[0046] In some embodiments, the output of the current sensor is a voltage signal proportional to its driving current. Converting this voltage signal into a first standard signal can make the signal have a strong anti-interference ability, which is conducive to signal remote transmission. For example, the first standard signal can be a standard current signal of 4-20mA.

[0047] In some embodiments, the preset current threshold may be the current magnitude corresponding to when the motor can maintain the torque not lower than the load requirement value. That is, the second moment t1 is the moment when the motor current drops to the corresponding holding torque lower than the load requirement value.

[0048] In some embodiments, a current signal corresponding to the current flowing through the motor can be introduced into a measuring device to obtain the current signal, which is more efficient and accurate.

[0049] In some embodiments, the driving device may include an electromagnetic driving component, and step S2 may include: S24, obtaining an electromagnetic driving signal of the electromagnetic driving component; S25, converting the electromagnetic driving signal into a second standard signal, wherein the driving signal may include a second standard signal; S26, when the second standard signal indicates that the electromagnetic driving parameter of the electromagnetic driving component is lower than a preset parameter threshold, determining the moment corresponding to the second standard signal as the third moment.

[0050] The method provided in the embodiment of the present application converts the electromagnetic driving signal of the electromagnetic driving component into a second standard signal, and then determines the third moment when the second standard signal indicates that the electromagnetic driving parameter of the electromagnetic driving component is lower than the preset parameter threshold. This can ensure a faster electromagnetic driving signal transmission speed while having higher reliability, which is beneficial to ensuring the reliability of the rod drop time finally obtained.

[0051] In some embodiments, the electromagnetic drive member may be an electromagnetic clutch.

[0052] In some embodiments, the preset parameter threshold may be a parameter value corresponding to when the electromagnetic clutch can maintain a torque not lower than the load demand value. That is, the third moment t2 is the moment when the operating parameter of the electromagnetic clutch drops to a corresponding holding torque lower than the load demand value.

[0053] In some embodiments, the electromagnetic driving signal may include a voltage signal, and step S24 may include: measuring the voltage across the electromagnetic driving component to obtain the voltage signal of the electromagnetic driving component, which is more efficient and accurate.

[0054] In some embodiments, the working mode of the electromagnetic clutch may include a constant current working mode and a constant pressure working mode. When the electromagnetic clutch is in the constant pressure working mode, the electromagnetic driving signal may include a voltage signal.

[0055] In some embodiments, the voltage across the electromagnetic driving component can be calculated according to the design of the electromagnetic driving component and the driving circuit of the driving device to obtain the voltage signal of the electromagnetic driving component.

[0056] In some embodiments, when the electromagnetic clutch is in the constant current working mode, the electromagnetic driving signal may include a current signal of the electromagnetic driving member. The current signal may correspond to the loop current when the electromagnetic clutch is in the constant current working mode.

[0057] In some embodiments, measuring the voltage across the electromagnetic driving component may include: connecting a resistor of a predetermined resistance in parallel across the electromagnetic driving component; measuring the current flowing through the resistor to obtain the resistor current; and determining the voltage signal of the electromagnetic driving component based on the resistor current and the predetermined resistance, with high calculation accuracy and efficiency.

[0058] In some embodiments, before step S1, the method provided in the embodiments of the present application may further include: lifting one / more compensating rod / adjusting rod driving devices or one / more safety rod driving devices to any position of the stroke, manually triggering the shutdown rod drop, so as to subsequently measure the control rod drop time. This method can be used to regularly measure the control rod drop time, which is beneficial to ensure the safety of fast neutron reactors.

[0059] In some embodiments, after step S4, the method provided by the embodiments of the present application may further include: when the rod drop time is greater than a rod drop time threshold, outputting an alarm signal.

[0060] The embodiments of the present application can timely remind operators and operating personnel by outputting alarm signals, which is beneficial to ensuring the safe operation of the fast neutron reactor.

[0061] In some embodiments, a fast neutron reactor may have multiple shutdown devices. The method provided in the embodiments of the present application may be used to determine the rod drop time of the control rod corresponding to each shutdown device. For ease of description and understanding, the following embodiments are described by taking a fast neutron reactor including two shutdown devices as an example, wherein the driving device of the first shutdown device includes a motor, and the driving device of the second shutdown device includes an electromagnetic clutch.

[0062] Example 1

[0063] When the fast neutron reactor is in normal operation and the protection parameter exceeds the limit and triggers the protection shutdown, the first moment t0 when the shutdown circuit breaker is opened can be automatically collected and recorded, and the second moment t1 when the current of the motor drops to the corresponding holding torque lower than the load demand value and the fourth moment t2 when the excitation current of the electromagnetic clutch of the control rod drive device drops to the corresponding holding torque lower than the load demand value can be calculated. 1' , the third time t2 when the continuous rod position of the control rod driving device of the first shutdown device drops to the position corresponding to the shutdown depth, and the fifth time t3 when the continuous rod position of the control rod driving device of the second shutdown device drops to the position corresponding to the shutdown depth. 2' The time for the control rods of the first shutdown device to fall can be determined according to the first time t0, the second time t1 and the third time t2. The time for the control rods of the second shutdown device to fall can be determined according to the first time t0, the fourth time t1 and the fifth time t2.

[0064] Example 2

[0065] When a fast neutron reactor is in cold shutdown condition, it is necessary to conduct regular tests on the control rod drop time measurement.

[0066] For the first set of shutdown device, one or more compensation rod / adjusting rod driving devices are lifted to any position of the stroke, and the shutdown rod drop is manually triggered. Then, the first moment t0 when the shutdown circuit breaker is opened, the second moment t1 when the motor current drops to the corresponding holding torque lower than the load demand value, and the third moment t2 when the continuous rod position of the control rod driving device drops to a position corresponding to the shutdown depth can be automatically recorded. The control rod drop time of the first set of shutdown device is tested one by one / in groups to obtain the rod drop curve.

[0067] For the second shutdown device, one or more safety rod driving devices can be lifted to any position of the travel, and the shutdown rod drop can be manually triggered to automatically record the sixth moment t when the shutdown circuit breaker is opened. 0' , calculate the seventh time t when the excitation current of the electromagnetic clutch of the control rod drive device drops to the corresponding holding torque lower than the load demand value 1' , the eighth time t when the continuous rod position of the control rod drive device drops to the specified value 2' , complete the control rod drop time test of the second set of shutdown device one by one / in groups, and obtain the rod drop curve.

[0068] In some embodiments, the rod drop time determination method provided in the embodiments of the present application can realize automatic measurement of the rod drop time of the control rod drive device of a fast neutron reactor, and the measurement accuracy can be less than 0.01s. When the rod drop time of the first set of shutdown devices and the second set of shutdown devices exceeds the corresponding rod drop time threshold, an alarm signal will be given.

[0069] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0070] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining a control rod drop time, applied to a fast neutron reactor, wherein the fast neutron reactor comprises a driving device for driving the control rod, characterized in that: The following steps are involved: S1, obtaining a shutdown signal of the fast neutron reactor and determining a time corresponding to the shutdown signal as a first time; S2, obtaining a driving signal of the driving device, and when the driving signal indicates that a driving parameter of the driving device is lower than a preset parameter threshold, determining a moment corresponding to the driving signal as a second moment; S3, obtaining a rod position measurement signal of the control rod, and when the rod position measurement signal indicates that the control rod has reached a rod position corresponding to a shutdown depth requirement, determining a time corresponding to the rod position measurement signal as a third time; S4. Determine a control rod drop time according to the first moment, the second moment and the third moment.

2. The method according to claim 1, characterized in that The S4 step includes: S41, determining a driving delay time of the driving device according to the first moment and the second moment; S42, determining the falling time of the control rod according to the second moment and the third moment; S43: Determine the rod drop time according to the driving delay time and the drop time.

3. The method according to claim 1, characterized in that The driving device includes a motor, and the step S2 includes: S21, obtaining a current signal of the motor; S22, converting the current signal into a first standard signal, wherein the drive signal includes the first standard signal; S23. When the first standard signal indicates that the current of the motor is lower than a preset current threshold, determine the moment corresponding to the first standard signal as the second moment, wherein the preset parameter threshold includes the preset current threshold.

4. The method according to claim 1, characterized in that: The driving device includes an electromagnetic driving member, and the step S2 includes: S24, obtaining an electromagnetic driving signal of the electromagnetic driving component; S25, converting the electromagnetic driving signal into a second standard signal, wherein the driving signal includes the second standard signal; S26. When the second standard signal indicates that the electromagnetic driving parameter of the electromagnetic driving component is lower than the preset parameter threshold, determine the moment corresponding to the second standard signal as the third moment.

5. The method according to claim 4, characterized in that The electromagnetic driving signal includes a voltage signal, and the step S24 includes: The voltage across the two ends of the electromagnetic driving component is measured to obtain a voltage signal of the electromagnetic driving component.

6. The method according to claim 5, characterized in that The measuring of the voltage at both ends of the electromagnetic driving component includes: A resistor with a predetermined resistance is connected in parallel at both ends of the electromagnetic driving member; measuring the current flowing through the resistor to obtain the resistor current; A voltage signal of the electromagnetic driving component is determined according to the resistance current and the predetermined resistance value.

7. The method according to any one of claims 1 to 6, characterized in that: Before the step S1, the method further comprises: Lift one or more compensation rod / adjustment rod driving devices or one or more safety rod driving devices to any position of the travel, and manually trigger the stack stop and rod drop.

8. The method according to any one of claims 1 to 6, characterized in that: After the step S4, the method further comprises: When the rod-drop time is greater than the rod-drop time threshold, an alarm signal is output.

9. The method according to any one of claims 1 to 6, characterized in that: After the step S4, the method further comprises: The rod drop curve of the control rod is determined according to the shutdown signal and the first moment obtained in step S1, the drive signal and the second moment obtained in step S2, the rod position measurement signal and the third moment obtained in step S3, and the rod drop time determined in step S4.

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