Double-valve linkage control method for high-temperature gas cooled reactor

Abstract

The invention relates to the technical field of emergency pressure control of a nuclear power plant, and discloses a double-valve linkage control method for a high-temperature gas cooled reactor. Comprising the following steps that the pressure of a main steam mother pipe serves as a control reference so that the pressure of the main steam mother pipe can be maintained within a pressure setting range, and a total bypass valve required opening degree instruction is calculated based on the deviation between the pressure of the main steam mother pipe and the pressure setting range; and the opening degrees of the two bypass valves are synchronously controlled in a staged mode according to the total bypass valve demand opening degree instruction. Asymmetric linkage control is performed on double valves in stages through pressure feedback of a main steam main pipe, so that the problems of system pressure oscillation caused by independent adjustment of each bypass valve and reactor jump caused by locking of a single valve due to over-limit of a condenser in the prior art are solved; coordinated and stable operation of multiple steam generator loops under the steam turbine tripping working condition is achieved, and the safety and economical efficiency of a nuclear power plant are improved.

Description

Technical Field

[0001] This invention relates to the field of emergency pressure control technology in nuclear power plants, specifically to a dual-valve linkage control method for high-temperature gas-cooled reactors. Background Technology

[0002] High-temperature gas-cooled reactor nuclear power plants typically employ a modular design, consisting of two or more reactor modules, each paired with a direct-flow steam generator. The steam generated by these generators converges into a main steam header, collectively driving a turbine to generate electricity. Each steam generator is equipped with a 100% capacity turbine bypass valve, used to directly discharge steam into the condenser when the turbine sheds load or trips, maintaining continuous reactor operation and preventing emergency shutdowns due to excessive pressure.

[0003] In existing technologies, each bypass valve in a high-temperature gas-cooled reactor independently controls the outlet pressure of its corresponding steam generator to maintain a constant pressure. When a nuclear power plant is operating at high load, if the turbine suddenly trips, all bypass valves will simultaneously open and discharge steam to the condenser to maintain the pressure in the main steam pipeline. However, the condenser's design capacity is typically only able to handle 100% of the steam discharge from a single steam generator, and cannot process all the steam from two steam generators simultaneously. To prevent condenser overpressure damage, the control system usually logically blocks the opening of one bypass valve, causing a sharp increase in pressure in the circuit containing the blocked steam generator, ultimately triggering the reactor's protection system and causing a trip. This chain reaction of "turbine trip" leading to "reactor trip" severely impacts the reliability and economics of the nuclear power plant. Summary of the Invention

[0004] This invention provides a dual-valve linkage control method for high-temperature gas-cooled reactors to solve the problem in the prior art where turbine tripping in high-load operation of high-temperature gas-cooled reactor power generation systems leads to reactor tripping.

[0005] In a first aspect, the present invention provides a dual-valve linkage control method for a high-temperature gas-cooled reactor, used in turbine tripping conditions, comprising the following steps: The main steam header pressure is used as the control reference to keep the main steam header pressure within the pressure setting range. The required opening command of the main bypass valve is calculated based on the deviation between the main steam header pressure and the pressure setting range. Based on the required opening degree command of the main bypass valve, the opening degree of the two bypass valves is controlled synchronously in stages.

[0006] When a turbine trips, the original independent control mode of the outlet pressure of each steam generator is switched to a unified control reference based on the main steam header pressure. By detecting real-time changes in the main steam header pressure, the required opening command of the main bypass valve to maintain system pressure stability is calculated. This command is then asymmetrically distributed to the two bypass valves according to a preset phased logic, allowing the two valves to open collaboratively at different rates in different phases. This maximizes the orderly discharge of steam within the condenser capacity limits. Asymmetrical linkage control of the two valves in stages through main steam header pressure feedback avoids system pressure oscillations caused by independent adjustment of each bypass valve in existing technologies, as well as reactor tripping problems caused by single valve closure due to condenser over-limit. This achieves coordinated and stable operation of multiple steam generator loops under turbine trip conditions without modifying the existing condenser capacity, improving the safety and economy of the nuclear power plant.

[0007] In one optional implementation, the step of synchronously controlling the opening of the two bypass valves in stages according to the main bypass valve's required opening command includes: When the required opening degree command of the main bypass valve increases from the minimum value to the first set value, the opening degree of one of the bypass valves is controlled to increase from 0% to the first preset value, while the other bypass valve is controlled to close. When the required opening degree command of the main bypass valve increases from the first set value to the second set value, the opening degree of one of the bypass valves is controlled to increase from the first preset value to 100%, and the opening degree of the other bypass valve is controlled to increase from 0% to the second preset value. When the opening command of the main bypass valve increases from the second set value to the maximum value, one of the bypass valves is controlled to remain 100% fully open, while the opening of the other bypass valve is controlled to increase from 0% to the third preset value.

[0008] By employing a three-stage, phased asymmetric control strategy, the opening actions of the two bypass valves are sequentially and progressively controlled in terms of timing and amplitude. This avoids the instantaneous impact on the downstream condenser caused by the simultaneous full opening of both valves. Under the limitation that the condenser capacity can only accept the steam flow of a single steam generator at 100% load, the system achieves a gradual discharge of the total steam production of the two steam generators. This not only ensures effective control of the main steam header pressure but also prevents the risk of condenser overpressure damage, thereby improving the overall safety of the system.

[0009] In one alternative implementation, the opening degree of the bypass valve varies linearly with the required opening degree command of the main bypass valve.

[0010] The linear relationship between the bypass valve opening degree and the main bypass valve opening degree command makes the valve action process smooth and continuous, avoiding flow shocks and pressure fluctuations that may be caused by nonlinear control. The main steam header pressure regulation process is more stable, the control system response characteristics are more predictable, and it helps to maintain the stability of the main steam system of the high-temperature gas-cooled reactor nuclear power plant.

[0011] In one alternative implementation, the method further includes: real-time monitoring of the vacuum level of the condenser downstream of the bypass valve, and forcibly closing all bypass valves when the vacuum level of the condenser exceeds a set protection threshold.

[0012] By monitoring the condenser vacuum in real time and using the protection logic to forcibly shut down all bypass valves after exceeding the threshold, a final line of defense is provided for the safety of the condenser equipment. This prevents damage to the condenser body due to the continuous deterioration of the condenser vacuum caused by control failure or transient disturbances, and ensures the safety and integrity of key equipment in nuclear power plants.

[0013] In one alternative implementation, the step of forcibly closing all bypass valves includes: The relay corresponding to the bypass valve is activated, forcibly resetting the control signals of all bypass valves to zero, thus directly closing the bypass valves.

[0014] The valve is quickly closed by using a relay-activated forced zero-setting bypass valve control signal. This method offers fast response, high reliability, and is unaffected by software logic delays or communication latency in the control device. It can cut off steam discharge in the shortest time when the condenser vacuum exceeds the limit, thus enhancing the independence and safety of the protection system.

[0015] In one alternative implementation, the operating load of the two steam generators corresponding to the two bypass valves is not less than 50% of their rated load.

[0016] The application of the dual-valve linkage control method is limited to high-load conditions where both steam generators are at least 50% loaded. This ensures that the control strategy is only activated under critical conditions where coordinated action of the dual valves is truly necessary to prevent reactor tripping. It avoids unnecessary activation of complex control logic at low loads, making the resource allocation of the control system more rational, while also ensuring the effectiveness and specificity of the control strategy.

[0017] In one optional implementation, the first setting value is 50% to 70% of the maximum value of the total bypass valve opening command, and the second setting value is 70% to 90% of the maximum value of the total bypass valve opening command.

[0018] By setting the first and second setpoints within a reasonable range of the maximum opening value command of the main bypass valve, flexible switching nodes are provided for different control stages. This ensures that the first bypass valve has enough time to open to a higher opening in advance to undertake the main emission task, while also leaving sufficient space for the timely intervention of the second bypass valve. This makes the linkage rhythm of the two valves more in line with the dynamic load capacity of the condenser, and improves the adaptability and robustness of the control.

[0019] In one optional implementation, the first preset value is 70% to 90%; and / or, the second preset value is 15% to 25%; and / or, the third preset value is 35% to 45%.

[0020] By using the aforementioned preset opening range, the first bypass valve takes on the main discharge flow and quickly approaches the fully open state, while the second bypass valve gradually participates in the discharge with a smaller opening increment. This fully utilizes the maximum capacity of a single bypass valve and avoids the capacity impact on the condenser when both bypass valves approach full opening at the same time. Under the constraint that the condenser can only accept 100% load flow from a single steam generator, efficient and orderly discharge of the total steam production of the two steam generators is achieved.

[0021] In one alternative implementation, each of the two bypass valves has a capacity of 100% of the rated load of a single steam generator.

[0022] The configuration of the bypass valve capacity matching the rated load of the steam generator ensures that the full flow bypass requirement of a single steam generator can be met when a single valve is opened to 100%. Under transient conditions such as turbine tripping, it can ensure that steam in any loop can be effectively discharged through the bypass valve, avoiding steam generator pressure runaway due to insufficient valve capacity, and improving the rationality and safety of the system design.

[0023] In one optional implementation, the pressure setting range is 10MPa-12MPa. The pressure setting range of 10MPa to 12MPa covers the rated operating pressure range of the main steam system of a high-temperature gas-cooled reactor nuclear power plant, providing a clear action threshold for the control system and avoiding frequent malfunctions of the bypass valve due to excessively low setting values. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1This is a schematic diagram of the structure of a high-temperature gas-cooled reactor system provided in an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached diagram: 1. Steam generator; 2. Main steam pipeline; 3. Bypass pipeline; 4. Main steam header; 5. Steam turbine; 6. Condenser; 7. Bypass valve. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The following is combined Figure 1 The following describes embodiments of the present invention.

[0029] Figure 1 The diagram illustrates a high-temperature gas-cooled reactor system, comprising two sets of steam generators 1 connected in parallel, each set corresponding to a reactor. Each steam generator 1 has a main steam pipeline 2 and a bypass pipeline 3 connected to its steam output end. Both main steam pipelines 2 are connected to a main steam header 4, the output end of which is connected to a steam turbine 5. The main steam header 4 collects steam from all steam generators 1 and delivers it to a single steam turbine 5, which then drives the turbine to generate electricity. A condenser 6 is installed downstream of the turbine 5 to recover low-quality steam output from the turbine 5, condensing it into water and recycling it back to the steam generators 1. The bypass pipeline 3, connected to the steam output end of the steam generators 1, is directly connected to the inlet end of the condenser 6. The bypass pipeline 3 allows low-quality steam generated by the steam generators 1 during startup or normal operation that cannot meet the operating requirements of the turbine 5 to be directly delivered to the condenser 6 for recovery without passing through the main steam header 4. In this application, during the emergency operation of turbine 5 tripping, bypass pipeline 3 is used to transport a portion of the steam generated by steam generator 1 to condenser 6 to maintain the steam pressure in the main steam header 4 within the pressure setting range. Each of the two bypass pipelines 3 is equipped with a bypass valve 7 to control the steam flow rate through the bypass pipelines 3.

[0030] According to an embodiment of the present invention, in one aspect, a dual-valve linkage control method for a high-temperature gas-cooled reactor is provided for the turbine 5 tripping condition of the high-temperature gas-cooled reactor system provided in this application, comprising the following steps: Using the pressure of the main steam header 4 as a unified control benchmark, the pressure control target is set to maintain the pressure of the main steam header 4 within a preset pressure setting range. The control system acquires the measured pressure value of the main steam header 4 in real time and calculates the pressure deviation signal between the measured value and the pressure setting range. Based on this pressure deviation signal, the control device generates a total bypass valve opening requirement command through its built-in control algorithm. This total bypass valve opening requirement command reflects the total opening of the bypass valve 7 required to maintain the pressure stability of the main steam header 4 under the current pressure deviation. The total bypass valve 7 opening requirement is an integrated parameter with a minimum value of 0 and a maximum value of 1.

[0031] Based on the generated main bypass valve opening requirement command, the control device implements synchronous but asymmetrical coordinated control of the opening of the two bypass valves 7 according to a preset phased control logic. Specifically, the control device divides the main bypass valve opening requirement command into several continuous control intervals. Within each control interval, the opening changes of the two bypass valves 7 follow different patterns, thereby enabling the two bypass valves 7 to gradually start steam discharge at different opening rates at different time periods.

[0032] When turbine 5 trips, the control unit automatically switches from the independent control mode of the outlet pressure of each steam generator 1 to a linked control mode with the pressure of the main steam header 4 as the unified control reference. By continuously monitoring the real-time change trend of the pressure of the main steam header 4, the control unit calculates the required opening command of the main bypass valve to maintain system pressure stability. Then, it asymmetrically distributes this command to the two bypass valves 7 according to a preset phased logic, so that the two bypass valves 7 open collaboratively at different opening change rates in different control phases. This phased asymmetrical linked control method ensures that within the capacity limit of the downstream condenser 6, the maximum steam receiving capacity of the condenser 6 is not exceeded, while maximizing the steam discharge, thereby orderly discharging steam to the condenser 6.

[0033] By using pressure feedback from the main steam header 4 to implement phased asymmetric linkage control of the dual bypass valves 7, the system pressure oscillation problem caused by the independent adjustment of each bypass valve 7 based on its own steam generator 1 outlet pressure, as in existing technologies, is effectively avoided. Simultaneously, it eliminates the risk of a sharp increase in the corresponding steam generator 1 loop pressure, ultimately leading to reactor tripping, caused by the logic blocking of a single bypass valve 7 due to condenser 6 capacity exceeding limits. This method achieves coordinated and stable operation of multiple steam generator 1 loops under turbine 5 tripping conditions without requiring capacity expansion of the existing condenser 6, thus improving the safety and economy of nuclear power plant operation.

[0034] In this embodiment, the step of synchronously controlling the opening of the two bypass valves 7 in stages according to the opening command of the main bypass valve includes: When the total bypass valve opening requirement command increases from the minimum value to the first preset value, the opening of one of the bypass valves 7 is controlled to increase from 0% to the first preset value, while the other bypass valve 7 is controlled to close. When the total bypass valve opening requirement command increases from the first preset value to the second preset value, the opening of one of the bypass valves 7 is controlled to increase from the first preset value to 100%, while the opening of the other bypass valve 7 is controlled to increase from 0% to the second preset value. When the total bypass valve opening requirement command increases from the second preset value to the maximum value, one of the bypass valves 7 is controlled to remain 100% fully open, while the opening of the other bypass valve 7 is controlled to increase from 0% to the third preset value.

[0035] During the turbine 5 tripping condition, after receiving the main bypass valve's opening command, the control device implements differentiated opening and closing control of the two bypass valves 7 according to a three-stage progressive logic. In the first stage, when the main bypass valve's opening command is between its minimum and first set value, the control device only drives the first bypass valve 7 from a fully closed state to gradually open to the first preset opening degree, while the second bypass valve 7 remains closed, achieving initial pressure relief with a single valve. In the second stage, when the main bypass valve's opening command enters the range between the first and second set values, the control device continues to increase the opening degree of the first bypass valve 7 until it is 100% fully open, while simultaneously starting the second bypass valve 7 from its closed state to the second preset opening degree, forming a coordinated pressure relief with both valves. In the third stage, when the main bypass valve's opening command reaches the range between the second and maximum values, the control device maintains the first bypass valve 7 at 100% full open, only continuing to increase the opening degree of the second bypass valve 7 to the third preset opening degree, completing the entire pressure relief process.

[0036] By employing a three-stage, phased, asymmetric control strategy, the opening actions of the two bypass valves 7 are sequentially and progressively controlled in terms of timing and amplitude. This avoids the instantaneous impact on the downstream condenser 6 caused by the simultaneous full opening of both valves. Under the limitation that the capacity of the condenser 6 can only accept the steam flow rate of a single steam generator at 100% load, the system achieves a gradual discharge of the total steam production of the two steam generators 1. This not only ensures effective control of the pressure of the main steam header 4 but also prevents the risk of overpressure damage to the condenser 6, thereby improving the overall safety of the system.

[0037] Furthermore, the opening degree of the bypass valve 7 changes linearly with the opening degree command required by the main bypass valve, that is, the opening degree of the bypass valve 7 increases linearly with the increase of the opening degree command required by the main bypass valve.

[0038] After calculating the required opening degree command of the main bypass valve, the control device establishes a first-order linear mapping relationship between the required opening degree command of the main bypass valve and the opening degree command of each bypass valve 7 through the function generation module. That is, the opening degree command of each bypass valve 7 changes proportionally to the required opening degree command of the main bypass valve. For every unit increase in the required opening degree command of the main bypass valve, the opening degree of the corresponding bypass valve 7 increases synchronously by one unit according to a fixed proportional coefficient. The whole process is without abrupt changes or sudden changes.

[0039] The linear relationship between the opening degree of bypass valve 7 and the opening degree command of the main bypass valve makes the valve action process smooth and continuous, avoiding flow shocks and pressure fluctuations that may be caused by nonlinear control. The pressure regulation process of the main steam header 4 is more stable, and the response characteristics of the control system are more predictable, which helps to maintain the stability of the main steam system of the high-temperature gas-cooled reactor nuclear power plant.

[0040] In one embodiment, the first setting value is 50% to 70% of the maximum value of the total bypass valve opening command, and the second setting value is 70% to 90% of the maximum value of the total bypass valve opening command.

[0041] When dividing the control device into three control zones, the maximum value of the main bypass valve's required opening command is used as the benchmark. The first setpoint is set within the range of 50% to 70% of the maximum value, and the second setpoint is set within the range of 70% to 90% of the maximum value. When the main bypass valve's required opening command increases from 0% to the 50%–70% range, the first control zone is entered; when the main bypass valve's required opening command increases from 50%–70% to the 70%–90% range, the second control zone is entered; and when the main bypass valve's required opening command exceeds 70%–90% up to 100%, the third control zone is entered.

[0042] By setting the first and second setpoints within a reasonable range of the maximum opening value command of the main bypass valve, flexible switching nodes are provided for different control stages. This ensures that the first bypass valve 7 has enough time to open to a higher opening degree in advance to undertake the main emission task, while also leaving sufficient space for the timely intervention of the second bypass valve 7. This makes the linkage rhythm of the two valves more in line with the dynamic load capacity of the condenser 6, and improves the adaptability and robustness of the control.

[0043] In one embodiment, the first preset value is 70% to 90%; and / or, the second preset value is 15% to 25%; and / or, the third preset value is 35% to 45%.

[0044] At the end of the first stage, the opening degree of the first bypass valve 7 reaches a first preset value, which is set between 70% and 90% of the total stroke. At the end of the second stage, the opening degree of the second bypass valve 7 reaches a second preset value, which is set between 15% and 25% of the total stroke. At the end of the third stage, the opening degree of the second bypass valve 7 reaches a third preset value, which is set between 35% and 45% of the total stroke. The control device controls the opening rate of the two bypass valves 7 in segments according to the above preset opening values, so that the first bypass valve 7 is close to fully open in the first stage, and the second bypass valve 7 gradually opens in subsequent stages.

[0045] By adopting the above-mentioned preset opening range, the first bypass valve 7 takes on the main discharge flow and quickly approaches the fully open state, while the second bypass valve 7 gradually participates in the discharge with a smaller opening increment. This fully utilizes the maximum capacity of a single bypass valve 7 and avoids the capacity impact on the condenser 6 when both bypass valves 7 approach full opening at the same time. Under the constraint that the condenser 6 can only accept 100% load flow of a single steam generator, the efficient and orderly discharge of the total steam production of the two steam generators 1 is achieved.

[0046] Specifically, in the first stage, as the main bypass valve opening command increases from 0 to 0.6, the control device only drives the first bypass valve 7 to gradually open from a fully closed state to 80%, while the second bypass valve 7 remains closed. In the second stage, as the main bypass valve opening command increases from 0.6 to 0.8, the control device continues to increase the opening of the first bypass valve 7 from 80% to 100% fully open, while simultaneously starting the second bypass valve 7 to gradually increase from a closed state to 20%. In the third stage, as the main bypass valve opening command increases from 0.8 to 1, the control device maintains the first bypass valve 7 at 100% fully open, only continuing to increase the opening of the second bypass valve 7 from 20% to 40%.

[0047] In this embodiment, a protection interlocking step is also included: real-time monitoring of the vacuum level of the condenser 6 downstream of the bypass valve 7, and when the vacuum level of the condenser 6 is greater than the set protection threshold, all bypass valves 7 are forcibly closed.

[0048] During the phased synchronous control of the opening of the two bypass valves 7 by the control device, the vacuum detection device of the condenser 6 continuously collects the vacuum level data of the condenser 6 and transmits it to the protection device. When the vacuum level of the condenser 6 deteriorates due to excessive steam discharge and exceeds the set protection threshold, the protection device immediately triggers the emergency protection logic, bypassing the conventional control command channel and directly sending a forced closure signal to the two bypass valves 7, causing the two bypass valves 7 to quickly enter the closed state and cut off the steam supply to the condenser 6.

[0049] By monitoring the vacuum level of condenser 6 in real time and using the protection logic of forcibly shutting down all bypass valves 7 after exceeding the threshold, the final line of defense for the safety of condenser 6 equipment is provided. This prevents damage to the condenser 6 body due to the continuous deterioration of the vacuum level of condenser 6 caused by control failure or transient disturbances, and ensures the safety and integrity of key equipment in nuclear power plants.

[0050] In one embodiment, the step of forcibly closing all bypass valves 7 includes: controlling the relay corresponding to the bypass valve 7 to activate, forcibly setting the control signal of all bypass valves 7 to zero, and directly closing the bypass valves 7.

[0051] When the vacuum level of condenser 6 exceeds the protection threshold and triggers the protection action, the protection device outputs a pulse drive signal to the relay connected in series with the control circuit of the two bypass valves 7. The relay contacts actuate to directly ground or disconnect the control signal input terminals of the two bypass valves 7, so that the opening command received by the control system of bypass valve 7 is instantly reduced to zero. In the case of power failure or signal loss, the actuator of bypass valve 7 closes quickly by relying on spring force or accumulator action.

[0052] The valve is quickly closed by using the relay-operated forced zero-setting bypass valve 7 control signal. It has a fast response speed and high reliability, and is not affected by the delay of the control device software logic or communication delay. It can cut off the steam discharge in the shortest time when the vacuum of condenser 6 exceeds the standard, thus enhancing the independence and safety of the protection system.

[0053] In one embodiment, the operating load of the two steam generators 1 corresponding to the two bypass valves 7 is not less than 50% of the rated load.

[0054] Before applying the dual-valve linkage control method for high-temperature gas-cooled reactors, it is necessary to ensure that both steam generators 1 of the high-temperature gas-cooled reactor nuclear power plant are operating under high load conditions, that is, the actual output power of both steam generators 1 reaches or exceeds 50% of their respective rated loads. Under this load level, when the turbine 5 trips, the total amount of steam generated by the two steam generators 1 will exceed the design limit of 100% load capacity of a single steam generator in the condenser 6. At this time, the control device activates the dual-valve linkage control strategy, and gradually discharges the total amount of steam from the two steam generators 1 into the condenser 6 by opening the two bypass valves 7 in stages, in a manner that does not exceed the capacity of the condenser 6.

[0055] The application of the dual-valve linkage control method is limited to high-load conditions where both steam generators are operating at no less than 50% load. This ensures that the control strategy is only activated under critical conditions where coordinated action of the dual valves is truly necessary to prevent reactor tripping. It avoids unnecessary activation of complex control logic at low loads, making the resource allocation of the control system more reasonable, while also ensuring the effectiveness and specificity of the control strategy.

[0056] In one embodiment, the capacity of each of the two bypass valves 7 is 100% of the rated load of a single steam generator 1.

[0057] In the selection and design of the two bypass valves 7 configured in the high-temperature gas-cooled reactor nuclear power plant, the flow capacity of each bypass valve 7 was designed to match the steam flow rate generated by a single steam generator 1 under its rated load. That is, the capacity of each bypass valve 7 is 100% of the rated load of a single steam generator 1. When the turbine 5 trips, the control device can, through a dual-valve linkage control method, open either bypass valve 7 to 100% full open as needed, ensuring that all steam from the corresponding steam generator 1 can be discharged at the maximum capacity of a single valve.

[0058] The configuration of bypass valve 7 with a capacity matching the rated load of steam generator 1 ensures that the full flow bypass requirement of a single steam generator 1 can be met when a single valve is opened to 100%. Under transient conditions such as turbine 5 tripping, it can ensure that steam in any loop can be effectively discharged through bypass valve 7, avoiding pressure runaway of steam generator 1 due to insufficient valve capacity, and improving the rationality and safety of system design.

[0059] In one embodiment, the pressure setting range is 10MPa-12MPa. Specifically, the stable pressure of the main steam header 4 is 11MPa. The pressure setting range of 10MPa to 12MPa covers the rated operating pressure range of the main steam system of the high-temperature gas-cooled reactor nuclear power plant, providing a clear action threshold for the control system and avoiding frequent malfunctions of the bypass valve 7 due to excessively low setting values.

[0060] The dual-valve linkage control method for high-temperature gas-cooled reactors provided in this application utilizes dual-valve linkage control to orderly and maximize the utilization of the bypass system's discharge capacity when the pressure in the main steam header 4 increases. This effectively prevents reactor pressure spikes caused by the closure of a single bypass valve 7 or insufficient discharge capacity, significantly improving the reliability of nuclear power plant operation. Through segmented opening logic, under the rigid constraint of the limited capacity of condenser 6, the method maximizes the discharge capacity of the total steam production of the two steam generators 1 without requiring expansion or modification of large equipment such as condenser 6. Furthermore, using the pressure in the main steam header 4 as a unified control benchmark avoids system pressure oscillations and instability that may be caused by the independent operation of multiple controllers, making the pressure control of the entire main steam system more unified and stable. Simultaneously, the built-in vacuum protection logic for condenser 6 ensures that while pursuing reactor stability, the safety of critical equipment such as condenser 6 is never sacrificed, forming a complete safety closed loop.

[0061] To ensure the effectiveness of the dual-valve linkage control method for the high-temperature gas-cooled reactor, a turbine 5 trip signal was simulated during normal unit operation. Upon detecting this signal, the control system automatically activated this control method. The steam header pressure transmitter was observed to maintain a stable pressure around 11 MPa under the linkage of the two sets of bypass valves 7 according to the aforementioned logic, and both reactors maintained stable operation without requiring a shutdown.

[0062] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A dual-valve linkage control method for a high-temperature gas-cooled reactor, characterized in that, For turbine (5) tripping conditions, the following steps are included: The pressure of the main steam header (4) is used as the control reference to keep the pressure of the main steam header (4) within the pressure setting range. The total bypass valve opening command is calculated based on the deviation between the pressure of the main steam header (4) and the pressure setting range. According to the required opening degree command of the main bypass valve, the opening degree of the two bypass valves (7) is controlled synchronously in stages.

2. The dual-valve linkage control method for high-temperature gas-cooled reactors according to claim 1, characterized in that, The step of synchronously controlling the opening of the two bypass valves (7) in stages according to the opening command of the main bypass valve includes: When the total bypass valve demand opening command increases from the minimum value to the first set value, the opening of one of the bypass valves (7) is controlled to increase from 0% to the first preset value, while the other bypass valve (7) is controlled to close. When the total bypass valve demand opening command increases from the first set value to the second set value, the opening of one of the bypass valves (7) is controlled to increase from the first preset value to 100%, and the opening of the other bypass valve (7) is controlled to increase from 0% to the second preset value. When the opening command of the main bypass valve increases from the second set value to the maximum value, one of the bypass valves (7) is controlled to remain 100% fully open, while the opening of the other bypass valve (7) is controlled to increase from 0% to the third preset value.

3. The dual-valve linkage control method for high-temperature gas-cooled reactors according to claim 2, characterized in that, The opening degree of the bypass valve (7) changes linearly with the opening degree command required by the main bypass valve.

4. The dual-valve linkage control method for high-temperature gas-cooled reactors according to any one of claims 1 to 3, characterized in that, Also includes: The vacuum level of the condenser (6) downstream of the bypass valve (7) is monitored in real time. When the vacuum level of the condenser (6) is greater than the set protection threshold, all bypass valves (7) are forcibly closed.

5. The dual-valve linkage control method for high-temperature gas-cooled reactors according to claim 4, characterized in that, The step of forcibly closing all bypass valves (7) includes: The relay corresponding to the bypass valve (7) is activated, forcibly setting the control signals of all bypass valves (7) to zero, and the bypass valves (7) are directly closed.

6. The dual-valve linkage control method for high-temperature gas-cooled reactors according to any one of claims 1 to 3, characterized in that, The operating load of the two steam generators (1) corresponding to the two bypass valves (7) is not less than 50% of the rated load.

7. The dual-valve linkage control method for high-temperature gas-cooled reactors according to claim 2 or 3, characterized in that, The first setting value is 50% to 70% of the maximum value of the total bypass valve opening command, and the second setting value is 70% to 90% of the maximum value of the total bypass valve opening command.

8. The dual-valve linkage control method for high-temperature gas-cooled reactors according to claim 2 or 3, characterized in that, The first preset value is 70% to 90%; and / or, the second preset value is 15% to 25%; and / or, the third preset value is 35% to 45%.

9. The dual-valve linkage control method for high-temperature gas-cooled reactors according to any one of claims 1 to 3, characterized in that, The capacity of each of the two bypass valves (7) is 100% of the rated load of a single steam generator (1).

10. The dual-valve linkage control method for high-temperature gas-cooled reactors according to any one of claims 1 to 3, characterized in that, The pressure setting range is 10MPa-12MPa.

Images