Nuclear power plant safety class dcs primary frequency modulation protection circuit and nuclear power plant control system
Patent Information
- Application Number
- CN202522077608.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-26
- Publication Date
- 2026-09-18
- Estimated Expiration
- 2035-09-26
AI Technical Summary
当此装置有故障时，有可能出现无法正常退出一次调频的情况，可能使核电站产生运行事件
[0029] Based on the above technical solution, in the nuclear power plant safety-level DCS primary frequency regulation protection circuit provided by this utility model embodiment, the first OR gate logic operator and the second OR gate logic operator perform logical OR processing on the input nuclear island-side detection signal to obtain the processing result, and send the processor result to the third OR gate logic operator. The third OR gate logic operator performs logical OR processing on the output results of the first OR gate logic operator and the second OR gate logic operator, as well as the turbine-side detection signal, and outputs the processing result. In this process, the first OR gate logic operator and the second OR gate logic operator are redundant structures. Under normal conditions, their input signals and output signals are the same. When one of the OR gate logic operators malfunctions, the other OR gate logic operator can still output a reliable result. This avoids the problem of not being able to generate a primary frequency regulation exit signal in a timely manner due to the failure of the first OR gate logic operator or the second OR gate logic operator when only one is set up, thus improving the reliability of the system operation.
Smart Images
Figure CN224774601U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of automatic control technology for nuclear power plants, specifically to a safety-grade DCS primary frequency regulation protection circuit and a nuclear power plant control system. Background Technology
[0002] Primary Frequency Control (PFDC) is an automatic power regulation function in nuclear power plants to support stable grid operation. When the grid frequency deviates from the standard value (e.g., 50Hz) due to sudden load changes, the nuclear power unit automatically increases or decreases its generating power within a second (typically 15-30 seconds) to quickly offset the frequency fluctuation. PFDC is a transient process during normal operation of a nuclear power plant. Due to the randomness of its amplitude and triggering frequency, as well as the uncertainty of the reactor's initial state during the transient, the plant's main parameters may deviate from the steady-state operating point, reducing the margin before the safety system can activate.
[0003] To further enhance power plant availability and prevent anticipated operational events, protection and interlocking logic are added to the primary frequency regulation design. This allows the primary frequency regulation function to be deactivated when main parameters reach certain limits or when the power plant's condition is unsuitable for load fluctuations. This function primarily considers the following conditions: a) reduced safety margin of main parameters; b) control rod travel limitations; c) reactor or turbine operating in an unstable state; d) turbine lacking frequency regulation capabilities; e) manual deactivation; f) deactivation due to other system equipment issues. After primary frequency regulation is deactivated, the operator can manually reactivate it if the deactivation conditions fail.
[0004] Taking a nuclear power plant as an example, the primary frequency regulation exit device of this nuclear power plant outputs a primary frequency regulation exit signal by performing an OR logic operation on all signals related to the primary frequency regulation exit conditions. When this device malfunctions, it may fail to exit the primary frequency regulation normally, which may cause an operational event in the nuclear power plant. Utility Model Content
[0005] In view of this, the present invention provides a highly reliable nuclear power plant safety-grade DCS primary frequency regulation protection circuit and nuclear power plant control system to ensure reliable operation of the nuclear power plant.
[0006] To achieve the above objectives, the present invention provides the following technical solutions:
[0007] A nuclear power plant safety-grade DCS primary frequency modulation protection circuit includes:
[0008] First OR gate logic unit, second OR gate logic unit and third OR gate logic unit;
[0009] The input terminals of the first OR gate logic unit and the second OR gate logic unit are used to input the nuclear island side detection signal, and the output terminals of the first OR gate logic unit and the second OR gate logic unit are used to output the nuclear island side primary frequency modulation exit signal obtained by performing logical OR processing on the nuclear island side detection signal.
[0010] The input terminal of the third OR gate logic operator is used to input the nuclear island-side primary frequency modulation exit signal and the turbine-side detection signal output by the first OR gate logic operator and the second OR gate logic operator. The output terminal of the third OR gate logic operator is used to output the processing result of performing a logical OR operation on the nuclear island-side primary frequency modulation exit signal and the turbine-side detection signal output by the first OR gate logic operator and the second OR gate logic operator.
[0011] Optionally, in the above-mentioned nuclear power plant safety-level DCS primary frequency modulation protection circuit, the nuclear island-side detection signals include at least: a main parameter safety margin reduction detection signal, a main control rod travel limit detection signal, and an unstable operating state detection signal;
[0012] The turbine-side detection signal includes a detection signal indicating whether the turbine is in a frequency regulation condition.
[0013] Optionally, in the above-mentioned nuclear power plant safety-level DCS primary frequency regulation protection circuit, the main parameter safety margin reduction detection signal includes at least one of the detection signal of whether the reactor power exceeds the limit and the detection signal of whether the reactor coolant temperature is abnormal.
[0014] The main control rod travel limit detection signal includes at least one of the following: a detection signal indicating whether the main control rod assembly is at the upper limit of the adjustment band and a detection signal indicating whether automatic or manual rod lifting is prohibited.
[0015] The unstable operating state detection signal includes at least one of the following: a detection signal indicating whether the pressure regulator pressure is abnormal, a detection signal indicating whether the pressure regulator water level is abnormal, and a detection signal indicating whether the steam generator water level is abnormal.
[0016] The detection signals for whether the turbine meets the frequency regulation conditions include the detection signal for whether the load closed-loop control is in use, the detection signal for whether the turbine regulating valve has reached the limit value, the detection signal for whether the turbine speed channel is faulty, and the detection signal for whether the difference between the frequency of the turbine output voltage and the grid frequency is greater than the target frequency.
[0017] Optionally, the aforementioned nuclear power plant safety-grade DCS primary frequency regulation protection circuit also includes:
[0018] The signal conditioning circuit has its output connected to the inputs of the first, second, and third OR gate logic operators, and is used to convert the nuclear island-side detection signal and the turbine-side detection signal into digital signals that can be recognized by the OR gate logic operators.
[0019] Optionally, in the above-mentioned nuclear power plant safety-level DCS primary frequency regulation protection circuit, the third OR gate logic unit includes:
[0020] First sub-OR gate logic unit, second sub-OR gate logic unit and third sub-OR gate logic unit;
[0021] The input terminals of the first and second sub-OR gate logic operators are used to input turbine-side detection signals; the output terminals of the first and second sub-OR gate logic operators are used to output the processing result of performing a logical OR operation on the turbine-side detection signals.
[0022] The input terminal of the third sub-OR gate logic unit is connected to the output terminals of the first OR gate logic unit, the second OR gate logic unit, the first sub-OR gate logic unit, and the second sub-OR gate logic unit. The output terminal of the third sub-OR gate logic unit is used to output the processing result of performing a logical OR operation on the input terminal of the third sub-OR gate logic unit and the output signals of the first OR gate logic unit, the second OR gate logic unit, the first sub-OR gate logic unit, and the second sub-OR gate logic unit.
[0023] Optionally, in the above-mentioned nuclear power plant safety-level DCS primary frequency regulation protection circuit, the first OR gate logic unit, the second OR gate logic unit, and the third OR gate logic unit are all implemented by a microprocessor MPU.
[0024] Optionally, in the above-mentioned nuclear power plant safety-level DCS primary frequency modulation protection circuit, the input signal of the input terminal of the third OR gate logic unit further includes: a primary frequency modulation manual exit signal.
[0025] Optionally, the control switch of the above-mentioned nuclear power plant safety-level DCS primary frequency regulation protection circuit is located at the input terminals of the first OR gate logic unit, the second OR gate logic unit, and the third OR gate logic unit.
[0026] Optionally, the aforementioned nuclear power plant safety-grade DCS primary frequency regulation protection circuit also includes:
[0027] A fault detector, which is connected to the first OR gate logic unit and the second OR gate logic unit, is used to activate the second OR gate logic unit when a fault is detected in the first OR gate logic unit.
[0028] A nuclear power plant control system includes the nuclear power plant safety-grade DCS primary frequency regulation protection circuit described in any one of the above-mentioned methods.
[0029] Based on the above technical solution, in the nuclear power plant safety-level DCS primary frequency regulation protection circuit provided by this utility model embodiment, the first OR gate logic operator and the second OR gate logic operator perform logical OR processing on the input nuclear island-side detection signal to obtain the processing result, and send the processor result to the third OR gate logic operator. The third OR gate logic operator performs logical OR processing on the output results of the first OR gate logic operator and the second OR gate logic operator, as well as the turbine-side detection signal, and outputs the processing result. In this process, the first OR gate logic operator and the second OR gate logic operator are redundant structures. Under normal conditions, their input signals and output signals are the same. When one of the OR gate logic operators malfunctions, the other OR gate logic operator can still output a reliable result. This avoids the problem of not being able to generate a primary frequency regulation exit signal in a timely manner due to the failure of the first OR gate logic operator or the second OR gate logic operator when only one is set up, thus improving the reliability of the system operation. Attached Figure Description
[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0031] Figure 1 A schematic diagram of the circuit structure of a primary frequency modulation protection circuit for a nuclear power plant safety-level DCS provided in this application embodiment;
[0032] Figure 2 This is a schematic diagram of the circuit structure of a primary frequency modulation protection circuit for a nuclear power plant safety-level DCS, provided as another embodiment of this application. Detailed Implementation
[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0034] By designing a primary frequency regulation protection circuit for a nuclear power plant safety-grade digital control system (DCS), the primary frequency regulation exit conditions on the nuclear island side are classified and the logic optimization of redundancy design is performed to prevent operational events caused by a single equipment failure and improve the reliability of nuclear power plant operation.
[0035] See Figure 1 The nuclear power plant safety-grade DCS primary frequency modulation protection circuit disclosed in this application may include: a first OR gate logic unit 101, a second OR gate logic unit 102, and a third OR gate logic unit 200. Figure 1 In the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200, DI represents the input pin of the corresponding logic unit, and DO represents the output pin of the corresponding logic unit. The first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200 are used to perform logical OR processing on the input signals. During the processing, as long as there is at least one 1 (high level) in each input port of the OR gate logic unit, the output signal of the OR gate logic unit is 1. The output signal of the output terminal is 0 only when all input signals are 0 (low level).
[0036] Taking a two-input OR gate as an example, the input truth table of the OR gate logic unit is as follows:
[0037] A B Y 0 0 0 0 1 1 1 0 1 1 1 1
[0038] The connection relationship between the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200 is as follows:
[0039] The input terminals of the first OR gate logic unit 101 and the second OR gate logic unit 102 are used to input the core island-side detection signal, and the output terminals of the first OR gate logic unit 101 and the second OR gate logic unit 102 are used to output the core island-side primary frequency modulation exit signal obtained by performing a logical OR operation on the core island-side detection signal. The core island-side detection signal is a pre-configured detection signal used to determine whether a primary frequency modulation exit signal needs to be generated. When the core island-side detection signal is at a low level (0), it indicates that no primary frequency modulation exit signal needs to be generated for the core island-side detection result. When the core island-side detection signal is at a high level (1), it indicates that a primary frequency modulation exit signal needs to be generated for the core island-side detection result. The core island-side detection signal may include multiple signals, each of which can be configured to a low level (0) or a high level (1) based on its corresponding detection result. When any one of the core island-side detection signals of the first OR gate logic unit 101 is configured to a high level (1), the output signal of the first OR gate logic unit 101 is a high level (1).
[0040] The input terminal of the third OR gate logic unit 200 is used to input the nuclear island-side primary frequency modulation exit signal and the turbine-side detection signal output by the first OR gate logic unit 101 and the second OR gate logic unit 102. The output terminal of the third OR gate logic unit 200 is used to output the processing result of performing a logical OR operation on the nuclear island-side primary frequency modulation exit signal and the turbine-side detection signal output by the first OR gate logic unit 101 and the second OR gate logic unit 102. The turbine-side detection signal is a pre-configured detection signal used to determine whether a primary frequency modulation exit signal needs to be generated. When the turbine-side detection signal is at a low level (0), it indicates that no primary frequency modulation exit signal needs to be generated for that turbine-side detection result. When the turbine-side detection signal is at a high level (1), it indicates that a primary frequency modulation exit signal needs to be generated for that turbine-side detection result. The turbine-side detection signal may include multiple signals, each of which can be configured to be at a low level (0) or a high level (1) based on its corresponding detection result. When any turbine-side detection signal of the third OR gate logic unit 200 is configured to a high level of 1, and the output result of the first OR gate logic unit 101 is 1 or the output result of the second OR gate logic unit 102 is 1, the output signal of the output terminal of the third OR gate logic unit 200 is a high level of 1.
[0041] In the aforementioned primary frequency modulation protection circuit of the nuclear power plant safety-level DCS, the first OR gate logic unit 101 and the second OR gate logic unit 102 are redundant structures. Under normal conditions, their input and output signals are the same. When one of the OR gate logic units malfunctions, the other OR gate logic unit can still output a reliable result. This avoids the problem of not being able to generate a primary frequency modulation exit signal in time due to the failure of either the first OR gate logic unit 101 or the second OR gate logic unit 102 when only one of the first OR gate logic unit 101 or the second OR gate logic unit 102 is set up, thus improving the reliability of the system operation.
[0042] In this embodiment, the signal content of the nuclear island-side detection signals and the turbine-side detection signals can be selected according to monitoring requirements. These nuclear island-side detection signals can be measured by sensors or extracted by the nuclear power plant operation control system. In this embodiment, the nuclear island-side detection signals include at least: main parameter safety margin reduction detection signals, main control rod stroke limitation detection signals, and unstable operation state detection signals; the turbine-side detection signals include detection signals for whether the turbine has frequency regulation conditions.
[0043] The main parameter safety margin reduction detection signal includes at least one of the following: a detection signal indicating whether the reactor power exceeds the limit and a detection signal indicating whether the reactor coolant temperature is abnormal; wherein, when the reactor power exceeds the limit, the state of the detection signal indicating whether the reactor power exceeds the limit is 1, otherwise the state is 0. When the reactor coolant temperature is abnormal, the state of the detection signal indicating whether the reactor coolant temperature is abnormal is 1, otherwise the state is 0.
[0044] The main control rod travel limit detection signal includes at least one of the following: a detection signal indicating whether the main control rod group is at the upper limit of the adjustment band and a detection signal indicating whether automatic or manual rod lifting is prohibited; when the main control rod group is at the upper limit of the adjustment band, the detection signal indicating whether the main control rod group is at the upper limit of the adjustment band is in state 1, otherwise the state is 0.
[0045] The unstable operation state detection signal includes at least one of the following: a detection signal for whether the pressure regulator is abnormal, a detection signal for whether the pressure regulator water level is abnormal, and a detection signal for whether the steam generator is abnormal. When the pressure regulator is abnormal, the state of the detection signal for whether the pressure regulator is abnormal is 1; otherwise, the state is 0. When the pressure regulator water level is abnormal, the state of the detection signal for whether the pressure regulator water level is abnormal is 1; otherwise, the state is 0. When the steam generator water level is abnormal, the state of the detection signal for whether the steam generator water level is abnormal is 1; otherwise, the state is 0.
[0046] The detection signals for whether the turbine meets the frequency regulation conditions include a detection signal for whether the load closed-loop control is in use, a detection signal for whether the turbine control valve has reached its limit value, a detection signal for whether the turbine speed channel is faulty, and a detection signal for whether the difference between the turbine output voltage frequency and the grid frequency is greater than the target frequency. When the load closed-loop control is not in use, the detection signal for whether the load closed-loop control is in use is 1; otherwise, it is 0. When the turbine control valve reaches its limit value, the detection signal for whether the turbine control valve has reached its limit value is 1; otherwise, it is 0. When the turbine speed channel is faulty, the detection signal for whether the turbine speed channel is faulty is 1; otherwise, it is 0. When the difference between the turbine output voltage frequency and the grid frequency is greater than the target frequency, the detection signal for whether the difference between the turbine output voltage frequency and the grid frequency is greater than the target frequency is 1; otherwise, it is 0.
[0047] All of the above signals can be obtained from sensors or from the nuclear power plant's operation and control system.
[0048] In this embodiment, the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200 can recognize switch input signals (digital signals). In this application, a signal conditioning circuit can be provided at the front end of the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200, and the output terminal of the signal conditioning circuit is connected to the input terminal of the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200. The signal conditioning circuit is used to convert the detection signals input to the front ends of the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200 into digital or analog signals that can be recognized by the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200. In this embodiment, a general signal conditioning circuit can be configured for the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200, or a separate signal conditioning circuit can be configured for each of the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200.
[0049] In this embodiment, the OR gate logic unit in the above embodiment can be powered by the power grid through the AC / DC power supply. The AC / DC power supply serves as the working power supply for the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200, and can convert the AC power of the power grid into DC power that is compatible with the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200.
[0050] In this embodiment, the third OR gate logic unit may include: a first sub-OR gate logic unit 201, a second sub-OR gate logic unit 202, and a third sub-OR gate logic unit 203. The input terminals of the first sub-OR gate logic unit 201 and the second sub-OR gate logic unit 202 are used to input turbine-side detection signals; the output terminals of the first sub-OR gate logic unit 201 and the second sub-OR gate logic unit 202 are used to output the processing result of performing a logical OR operation on the turbine-side detection signals; the third sub-OR gate logic unit 203... The input terminal of the third sub-OR gate 203 is connected to the output terminals of the first OR gate logic unit 101, the second OR gate logic unit 102, the first sub-OR gate logic unit 201, and the second sub-OR gate logic unit 202. The output terminal of the third sub-OR gate logic unit 203 is used to output the processing result of performing a logical OR operation between the input terminal of the third sub-OR gate logic unit 203 and the output signals of the first OR gate logic unit 101, the second OR gate logic unit 102, the first sub-OR gate logic unit 201, and the second sub-OR gate logic unit 202. In this embodiment, the first sub-OR gate logic unit 201 and the second sub-OR gate logic unit 202 are redundant, and both are used to perform logical OR analysis on the turbine-side detection signal and generate analysis results. The input terminals of the third sub-OR gate logic unit 203 are respectively connected to the output terminals of the first OR gate logic unit 101, the second OR gate logic unit 102, the first sub-OR gate logic unit 201, and the second sub-OR gate logic unit 202. It is used to perform logical OR analysis on the output results of the first OR gate logic unit 101, the second OR gate logic unit 102, the first sub-OR gate logic unit 201, and the second sub-OR gate logic unit 202. In this scheme, redundant OR gate logic units are used to perform logical processing on the nuclear island side detection signal and the turbine side detection signal, which prevents the failure of one OR gate logic unit to output or the erroneous output of the primary frequency modulation exit signal in the event of a failure of one of the OR gate logic units, thus ensuring the reliable operation of the nuclear power plant system.
[0051] In this embodiment, the first OR gate logic unit 101, the second OR gate logic unit 102, the third OR gate logic unit 200, the first sub-OR gate logic unit 201, the second sub-OR gate logic unit 202, and the third sub-OR gate logic unit 203 can all be implemented by a microprocessor MPU or by a processor MCU.
[0052] In this embodiment, the primary frequency modulation exit signal can also be manually controlled by the user. In this case, the input signal at the input terminal of the third OR gate logic unit 200 also includes a primary frequency modulation manual exit signal. The primary frequency modulation exit signal input to the input terminal of the third OR gate logic unit 200 can be actively generated by the user. When the user needs the circuit to output a primary frequency modulation exit signal, a primary frequency modulation manual exit signal in a high-level 1 state is injected into the third OR gate logic unit 200 through a relevant signal output circuit or switching circuit. At this time, the output terminal of the third OR gate logic unit 200 can generate a primary frequency modulation exit signal under the intervention of the primary frequency modulation manual exit signal.
[0053] In this embodiment, the user can select which nuclear island-side detection signals and turbine-side detection signals to inject into the first OR gate logic unit 101 and the third OR gate logic unit 200 according to actual needs or the operating conditions of the nuclear power plant system. To facilitate the user's selection of the injected signals, the above scheme may also include a control switch. The control switch is set at the input terminals of the first OR gate logic unit 101, the second OR gate logic unit 102, and the third OR gate logic unit 200. The switch has multiple paths, each path corresponding to a nuclear island-side detection signal or a turbine-side detection signal, and each path is provided with a sub-switch. The user can select whether to inject the detection signal into the corresponding OR gate logic unit by controlling the on / off state of the sub-switches in each path.
[0054] In this embodiment, the activation of the second OR gate logic unit 102 can also be selected based on the fault state of the first OR gate logic unit 101. In this case, the solution may further include a fault detector connected to both the first and second OR gate logic units 101 and 102. This detector is used to activate the second OR gate logic unit 102 when a fault is detected in the first OR gate logic unit 101. In this case, the second OR gate logic unit 102 does not need to remain continuously operational; it is only activated when the first OR gate logic unit 101 fails. This reduces circuit operating conditions and heat generation, and also improves the overall lifespan of the circuit.
[0055] In summary, the proposed solution improves the reliability of reactor protection logic by performing redundancy analysis on the nuclear island-side detection signals and using OR logic operations on the nuclear island-side detection signals in different channels. This avoids potential operational events caused by the inability to exit primary frequency modulation due to the failure of a single OR gate logic unit. Through redundancy design optimization, the risk is reduced.
[0056] This embodiment also provides a nuclear power plant control system, which includes any of the above-mentioned nuclear power plant safety-grade DCS primary frequency regulation protection circuits.
[0057] For ease of description, the above system is described by dividing it into various modules based on their functions. Of course, in implementing this utility model, the functions of each module can be implemented in one or more software and / or hardware components.
[0058] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. Components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.
[0059] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0060] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A primary frequency modulation protection circuit for a nuclear power plant safety-grade DCS, characterized in that, include: First OR gate logic unit, second OR gate logic unit and third OR gate logic unit; The input terminals of the first OR gate logic unit and the second OR gate logic unit are used to input the nuclear island side detection signal, and the output terminals of the first OR gate logic unit and the second OR gate logic unit are used to output the nuclear island side primary frequency modulation exit signal obtained by performing logical OR processing on the nuclear island side detection signal. The input terminal of the third OR gate logic operator is used to input the nuclear island-side primary frequency modulation exit signal and the turbine-side detection signal output by the first OR gate logic operator and the second OR gate logic operator. The output terminal of the third OR gate logic operator is used to output the processing result of performing a logical OR operation on the nuclear island-side primary frequency modulation exit signal and the turbine-side detection signal output by the first OR gate logic operator and the second OR gate logic operator.
2. The nuclear power plant safety-grade DCS primary frequency modulation protection circuit according to claim 1, characterized in that, The nuclear island-side detection signals include at least: a main parameter safety margin reduction detection signal, a main control rod travel limitation detection signal, and an unstable operating state detection signal; The turbine-side detection signals include detection signals indicating whether the turbine is in a frequency regulation condition.
3. The nuclear power plant safety-grade DCS primary frequency modulation protection circuit according to claim 2, characterized in that, The main parameter safety margin reduction detection signal includes at least one of the following: a detection signal indicating whether the reactor power exceeds the limit and a detection signal indicating whether the reactor coolant temperature is abnormal. The main control rod travel limit detection signal includes at least one of the following: a detection signal indicating whether the main control rod assembly is at the upper limit of the adjustment band and a detection signal indicating whether automatic or manual rod lifting is prohibited. The unstable operating state detection signal includes at least one of the following: a detection signal indicating whether the pressure regulator pressure is abnormal, a detection signal indicating whether the pressure regulator water level is abnormal, and a detection signal indicating whether the steam generator water level is abnormal. The detection signals for whether the turbine meets the frequency regulation conditions include the detection signal for whether the load closed-loop control is in use, the detection signal for whether the turbine regulating valve has reached the limit value, the detection signal for whether the turbine speed channel is faulty, and the detection signal for whether the difference between the frequency of the turbine output voltage and the grid frequency is greater than the target frequency.
4. The nuclear power plant safety-grade DCS primary frequency modulation protection circuit according to claim 1, characterized in that, Also includes: The signal conditioning circuit has its output connected to the inputs of the first, second, and third OR gate logic operators, and is used to convert the nuclear island-side detection signal and the turbine-side detection signal into digital signals that can be recognized by the OR gate logic operators.
5. The nuclear power plant safety-grade DCS primary frequency modulation protection circuit according to claim 1, characterized in that, The third OR gate logic operator includes: First sub-OR gate logic unit, second sub-OR gate logic unit and third sub-OR gate logic unit; The input terminals of the first and second sub-OR gate logic operators are used to input turbine-side detection signals; the output terminals of the first and second sub-OR gate logic operators are used to output the processing result of performing a logical OR operation on the turbine-side detection signals. The input terminal of the third sub-OR gate logic unit is connected to the output terminals of the first OR gate logic unit, the second OR gate logic unit, the first sub-OR gate logic unit, and the second sub-OR gate logic unit. The output terminal of the third sub-OR gate logic unit is used to output the processing result of performing a logical OR operation on the input terminal of the third sub-OR gate logic unit and the output signals of the first OR gate logic unit, the second OR gate logic unit, the first sub-OR gate logic unit, and the second sub-OR gate logic unit.
6. The nuclear power plant safety-grade DCS primary frequency modulation protection circuit according to claim 1, characterized in that, The first, second, and third OR gate logic units are all implemented by a microprocessor MPU.
7. The nuclear power plant safety-grade DCS primary frequency modulation protection circuit according to claim 1, characterized in that, The input signals at the input terminal of the third OR gate logic unit also include: a primary frequency modulation manual exit signal.
8. The nuclear power plant safety-grade DCS primary frequency modulation protection circuit according to claim 1, characterized in that, A control switch is provided at the input terminals of the first OR gate logic unit, the second OR gate logic unit, and the third OR gate logic unit.
9. The nuclear power plant safety-grade DCS primary frequency modulation protection circuit according to claim 1, characterized in that, Also includes: A fault detector, which is connected to the first OR gate logic unit and the second OR gate logic unit, is used to activate the second OR gate logic unit when a fault is detected in the first OR gate logic unit.
10. A nuclear power plant control system, characterized in that, Includes the nuclear power plant safety-grade DCS primary frequency modulation protection circuit as described in any one of claims 1-9.