Method and system for automatic control of protection against non-uniform boron dilution in nuclear power plants

Abstract

The present application relates to a nuclear power plant non-uniform boron dilution protection automatic control method and system, which executes the following steps under the whole working condition of reactor from power operation to complete discharge: real-time monitoring of the reactor coolant system; judging whether the loss of forced circulation signal, the loss of natural circulation signal and the residual heat removal system non-connection signal are detected; if yes, obtaining the average temperature of the reactor coolant; and executing the control of non-uniform boron dilution protection action according to the average temperature of the reactor coolant. Through the above steps, the problem caused by the false triggering of non-uniform boron dilution protection under the complete discharge working condition can be avoided, and the start or non-start of non-uniform boron dilution protection action is an automatic control process, which can prevent the risk of operator misoperation, avoid human error, and further improve the safety of nuclear power unit operation.

Description

Automatic control methods and systems for protecting nuclear power plants against non-uniform boron dilution Technical Field

[0001] This invention relates to the technical field of pressurized water reactors in nuclear power plants, and more specifically, to an automatic control method and system for protecting against non-uniform boron dilution in nuclear power plants. Background Technology

[0002] A reactor boron dilution accident refers to the accidental introduction of boric acid solution or demineralized water with a low boron content into the reactor coolant system, leading to increased core reactivity and threatening reactor safety. Based on the rate of reactivity introduction, boron dilution accidents can be classified into two types: homogeneous boron dilution and heterogeneous boron dilution.

[0003] To prevent low-boron water entering the reactor coolant system through the chemical and volume control system from forming clear water masses and thus causing the risk of non-uniform boron dilution, a nuclear power plant has also implemented a non-uniform boron dilution protection measure: when the residual heat removal system is not connected to the reactor coolant system, and forced circulation and natural circulation are lost, a non-uniform boron dilution protection system is established. The inlet of the charging pump of the chemical and volume control system is switched from the control box to the refueling water tank to prevent low-boron water from being injected into the reactor coolant system through the charging pump of the chemical and volume control system and forming low-boron concentration water masses in the main pump casing and main pipeline transition section.

[0004] The drawback of this protection measure against non-uniform boron dilution is that unnecessary triggering occurs during complete unloading, introducing the risk of malfunction. Malfunctions can lead to the following problems: directly affecting normal unit maintenance and potentially causing industrial safety incidents; posing a risk of accidental leakage of radioactive water, which could contaminate maintenance personnel and potentially cause radioactive incidents; and posing a risk of uncontrollable water level drops in the refueling tank, affecting the power plant's overall power generation schedule. Furthermore, the current solution relies on manual judgment and operation to activate and deactivate the non-uniform boron dilution protection system, which carries the risk of human error. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an automatic control method and system for protecting nuclear power plants from non-uniform boron dilution.

[0006] The technical solution adopted by this invention to solve its technical problem is: to construct an automatic control method for preventing non-uniform boron dilution in nuclear power plants, which executes the following steps under all operating conditions of the reactor from power operation to complete unloading:

[0007] Real-time monitoring of the reactor coolant system;

[0008] Determine whether the loss of forced circulation signal, loss of natural circulation signal, or disconnection of waste heat removal system signal is detected;

[0009] If so, obtain the average temperature of the reactor coolant;

[0010] Control of the protection action against non-uniform boron dilution is performed based on the average temperature of the reactor coolant.

[0011] In the automatic control method for preventing non-uniform boron dilution in nuclear power plants according to the present invention, the step of controlling the action of preventing non-uniform boron dilution based on the average temperature of the reactor coolant includes:

[0012] Determine whether the average temperature of the reactor coolant is greater than a preset temperature;

[0013] If the average temperature of the reactor coolant is greater than the preset temperature, the protection action against non-uniform boron dilution will be activated.

[0014] If the average temperature of the reactor coolant is less than or equal to the preset temperature, the protection against non-uniform boron dilution will not be activated.

[0015] In the automatic control method for preventing non-uniform boron dilution protection in nuclear power plants according to the present invention, obtaining the average temperature of the reactor coolant includes:

[0016] Obtain multiple real-time temperatures of the reactor coolant;

[0017] The multiple real-time temperatures are preprocessed to obtain multiple effective temperatures;

[0018] The average temperature of the reactor coolant is obtained by averaging the multiple effective temperatures.

[0019] In the automatic control method for preventing non-uniform boron dilution in nuclear power plants according to the present invention, the preset temperature is obtained through the following steps:

[0020] Obtain the downstream inlet temperature of the waste heat removal system during the unit's downstream movement;

[0021] Obtain the downward exit temperature of the waste heat removal system during the unit's downward movement;

[0022] Obtain the upward inlet temperature of the waste heat removal system during the unit's upward movement;

[0023] Obtain the upward exit temperature of the waste heat removal system during the unit's upward movement;

[0024] Based on the analysis of the upward access temperature and the upward exit temperature, the upward temperature change trend of the waste heat discharge system is obtained.

[0025] Based on the analysis of the downlink access temperature and the downlink exit temperature, the downlink temperature change trend of the waste heat discharge system is obtained;

[0026] The preset temperature is obtained by analyzing the upward and downward temperature change trends of the waste heat discharge system.

[0027] In the automatic control method for preventing non-uniform boron dilution protection in nuclear power plants according to the present invention, the method further includes:

[0028] After the non-uniform boron dilution protection action is activated, an alarm signal for non-uniform boron dilution protection is output.

[0029] In the automatic control method for preventing non-uniform boron dilution protection in nuclear power plants according to the present invention, the method further includes:

[0030] Determine whether a reset control signal has been received;

[0031] If so, a reset operation is performed according to the reset control signal.

[0032] This invention also provides an automatic control system for protecting nuclear power plants against non-uniform boron dilution, comprising:

[0033] The signal monitoring module is used for real-time monitoring of the reactor coolant system;

[0034] The first logic judgment module is used to determine whether the loss of forced circulation signal, loss of natural circulation signal, and waste heat discharge system disconnection signal are detected. If so, the first logic signal is output.

[0035] The control unit is configured to, upon receiving the first logic signal, acquire the average temperature of the reactor coolant and, based on the average temperature of the reactor coolant, control the action to prevent non-uniform boron dilution protection.

[0036] In the automatic control system for preventing non-uniform boron dilution in nuclear power plants according to the present invention, the control unit includes:

[0037] Temperature monitoring module, used to obtain the average temperature of reactor coolant;

[0038] The comparison module is used to compare the average temperature of the reactor coolant with a preset temperature and output a comparison signal;

[0039] The second logic judgment module is used to output a second logic signal based on the first logic signal and the comparison signal;

[0040] The trigger control module is used to control the action of preventing non-uniform boron dilution protection according to the second logic signal.

[0041] The automatic control system for preventing non-uniform boron dilution in nuclear power plants according to the present invention also includes:

[0042] The alarm module is used to output an alarm signal according to the alarm control signal output by the trigger control module after the non-uniform boron dilution protection action is activated.

[0043] The reset module is used to output a reset signal to the trigger control module based on the received reset control signal.

[0044] In the automatic control system for preventing non-uniform boron dilution in nuclear power plants described in this invention, both the first logic judgment module and the second logic judgment module are AND gates.

[0045] The trigger control module is an RS trigger.

[0046] The automatic control method and system for preventing non-uniform boron dilution in nuclear power plants, as described in this invention, has the following beneficial effects: During all operating conditions of the reactor from power operation to complete unloading, the following steps are executed: real-time monitoring of the reactor coolant system; determination of whether a forced circulation signal, a natural circulation signal, or a residual heat removal system disconnection signal is detected; if so, acquisition of the average temperature of the reactor coolant; and control of the non-uniform boron dilution protection action based on the average temperature of the reactor coolant. Through the above steps, this invention avoids problems caused by false triggering of the non-uniform boron dilution protection during complete unloading. Furthermore, the activation or deactivation of the non-uniform boron dilution protection action is an automatic control process, preventing operator error and further improving the safety of nuclear power unit operation. Attached Figure Description

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0048] Figure 1 is a flowchart illustrating the automatic control method for preventing non-uniform boron dilution in nuclear power plants provided in an embodiment of the present invention.

[0049] Figure 2 is a schematic diagram of the preset temperature selection provided by the present invention;

[0050] Figure 3 is a logic diagram of the automatic control system for protecting against non-uniform boron dilution in nuclear power plants provided in an embodiment of the present invention. Detailed Implementation

[0051] 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, and 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.

[0052] Referring to Figure 1, the present invention provides a preferred embodiment of an automatic control method for protecting nuclear power plants from non-uniform boron dilution.

[0053] As shown in Figure 1, the automatic control method for preventing non-uniform boron dilution in this nuclear power plant performs the following steps under all operating conditions of the reactor, from power operation to complete unloading:

[0054] Step S101: Monitor the reactor coolant system in real time.

[0055] Specifically, the real-time monitoring of the reactor coolant system is carried out under all operating conditions of the reactor, meaning that the automatic control method for preventing non-uniform boron dilution in nuclear power plants of the present invention is effective under all operating conditions of the reactor.

[0056] Step S102: Determine whether the loss of forced circulation signal, loss of natural circulation signal, and waste heat discharge system disconnection signal are detected.

[0057] Specifically, the activation conditions for the protection action against non-uniform boron dilution are: loss of forced circulation in the primary coolant system, loss of natural circulation in the primary coolant system, and disconnection of the residual heat removal system. Therefore, in this embodiment of the invention, the status of the primary coolant system and the residual heat removal system needs to be monitored in real time throughout all operating conditions of the reactor, from power operation to complete unloading (i.e., all operating conditions of the reactor), thereby monitoring whether forced circulation in the primary coolant system is lost, whether natural circulation in the primary coolant system is lost, and whether the residual heat removal system is connected. When forced circulation in the primary coolant system is lost, a signal indicating loss of forced circulation is generated; when natural circulation in the primary coolant system is lost, a signal indicating loss of natural circulation is generated.

[0058] Step S103: If yes, obtain the average temperature of the reactor coolant.

[0059] Optionally, in this embodiment of the invention, obtaining the average temperature of the reactor coolant includes: obtaining multiple real-time temperatures of the reactor coolant; preprocessing the multiple real-time temperatures to obtain multiple effective temperatures; and averaging the multiple effective temperatures to obtain the average temperature of the reactor coolant.

[0060] For example, three real-time temperatures of the reactor coolant can be acquired over a period of time. These three real-time temperatures can then be preprocessed to remove invalid temperatures, resulting in two real-time temperatures, which are considered valid temperatures. The average of these two temperatures is then calculated to obtain the average temperature of the reactor coolant. By averaging multiple valid temperatures, redundancy performance can be enhanced, and single-failure scenarios can be avoided.

[0061] Step S104: Control the action to prevent non-uniform boron dilution protection based on the average temperature of the reactor coolant.

[0062] Optionally, in this embodiment of the invention, controlling the non-uniform boron dilution protection action based on the average temperature of the reactor coolant includes: determining whether the average temperature of the reactor coolant is greater than a preset temperature; if the average temperature of the reactor coolant is greater than the preset temperature, then activating the non-uniform boron dilution protection action; if the average temperature of the reactor coolant is less than or equal to the preset temperature, then not activating the non-uniform boron dilution protection action. Activating the non-uniform boron dilution protection action involves: isolating the chemical and volumetric control systems and switching the charging pump inlet from the volumetric control box to the refueling water tank.

[0063] In this embodiment of the invention, when the loss of forced circulation signal and natural circulation signal is detected, and the waste heat removal system is not connected at the same time, it is determined whether the average temperature of the reactor coolant is greater than a preset temperature. If the average temperature of the reactor coolant is greater than the preset temperature, the non-uniform boron dilution protection action is activated; otherwise, the non-uniform boron dilution protection action is not activated. This method can effectively avoid unnecessary triggering of the non-uniform boron dilution protection system during complete unloading when the waste heat removal system is shut down, thus preventing malfunctions. This avoids a series of problems caused by malfunctions (such as affecting normal unit maintenance work and leading to industrial safety incidents; posing a risk of accidental leakage of radioactive water and leading to radioactive incidents; and causing uncontrollable drops in the refueling tank water level, affecting the overall power plant power generation plan).

[0064] Optionally, in this embodiment of the invention, the preset temperature is obtained through the following steps: obtaining the downward access temperature of the waste heat removal system when the unit is descending; obtaining the downward exit temperature of the waste heat removal system when the unit is descending; obtaining the upward access temperature of the waste heat removal system when the unit is ascending; obtaining the upward exit temperature of the waste heat removal system when the unit is ascending; analyzing the upward access temperature and the upward exit temperature to obtain the upward temperature change trend of the waste heat removal system; analyzing the downward access temperature and the downward exit temperature to obtain the downward temperature change trend of the waste heat removal system; analyzing the upward temperature change trend and the downward temperature change trend of the waste heat removal system to obtain the preset temperature.

[0065] Specifically, as shown in Figure 2, during the reactor's downhill operation (which is a process of continuous cooling and depressurization), after the reactor is shut down, it cools down and enters a hot shutdown state. Then, it is cooled by the steam generator to the temperature T2 at which the residual heat removal system is connected. Subsequently, it is cooled by the residual heat removal system and maintained at a temperature below a certain temperature T3. After the reactor core is completely unloaded and the residual heat removal system is removed from the primary circuit, the primary circuit gradually cools down naturally to the ambient temperature.

[0066] As shown in Figure 2, during the reactor's up-circuit operation (which is a continuous process of heating and pressurization), when the reactor is in a fully unloaded state, the primary loop temperature is ambient temperature. Before core loading, the residual heat removal system is connected to the primary loop. After core loading is completed, the primary loop temperature is controlled below temperature T3 through the residual heat removal system. Then, the primary loop is heated to the residual heat removal system exit temperature T2 by the main pump heat pump, and the residual heat removal system is then normally disconnected from the primary loop. Finally, the turbine bypass system controls the primary loop temperature to reach hot shutdown.

[0067] The operating condition corresponding to the non-uniform boron dilution prevention system is when the residual heat removal system is not connected under high unit operating conditions, and the average reactor coolant temperature is above T2. Therefore, the non-uniform boron dilution prevention protection action can be prohibited when T2 is below T2. Simultaneously, to prevent the non-uniform boron dilution prevention system from activating after the residual heat removal system is disconnected during complete unloading, its operation is prohibited before the residual heat removal system is disconnected. Based on this principle, the preset temperature can be selected between temperatures T2 and T3, denoted as T1. Furthermore, considering a certain margin, the preset temperature T1 can be selected as low as possible.

[0068] In Figure 3, RHR stands for Residual Heat Removal System.

[0069] Furthermore, the automatic control method for preventing non-uniform boron dilution protection in the nuclear power plant also includes: after the non-uniform boron dilution protection action is activated, an alarm signal for triggering non-uniform boron dilution protection is output.

[0070] Furthermore, the automatic control method for preventing non-uniform boron dilution protection in this nuclear power plant also includes: determining whether a reset control signal has been received; if so, performing a reset operation based on the reset control signal. The reset control signal can be triggered by the system or generated by the operator. This setting allows for restoration to normal operation after an accident is handled, by executing a reset operation (such as a reset indication and drive command) through the reset control signal.

[0071] Furthermore, in this embodiment of the invention, the control logic of the automatic control method for preventing non-uniform boron dilution protection in nuclear power plants can be set according to the following steps:

[0072] First, we analyze the operating conditions corresponding to the protection against non-uniform boron dilution.

[0073] Specifically, the triggering conditions for non-uniform boron dilution protection are: loss of forced circulation, loss of natural circulation, and the residual heat removal system not being connected to the reactor coolant system. All three conditions must be met. When the unit is operating at power (e.g., in condition 1), it relies on forced circulation to cool the core. When forced circulation is lost, the unit must be retracted and rely on natural circulation to cool the core for depressurization and cooling. When the unit's temperature and pressure drop to a point where natural circulation cannot be established, the residual heat removal system is connected to cool the core. When the residual heat removal system is connected to the reactor coolant system, non-uniform boron dilution protection is not needed and will not be triggered. After the reactor is completely unloaded (condition 14), the core is empty of fuel and does not require cooling, so the residual heat removal system can be disconnected from the reactor coolant system. At this time, the signals for loss of forced circulation and loss of natural circulation are simultaneously present, causing non-uniform boron dilution protection to be triggered. Since the core is now empty of fuel, there will be no accidental dilution.

[0074] Therefore, the operating conditions corresponding to the protection against non-uniform boron dilution (taking the unit's downhill process as an example) are as follows: it will be falsely triggered in operating condition 14 (complete unloading condition, i.e., the core fuel is completely unloaded)). That is, when the RHR exits the reactor coolant system, the protection against non-uniform boron dilution will be triggered. During the unit's uphill process, the RHR access / exit status is the same as during the downhill process.

[0075] Secondly, the exit conditions for the protection against non-uniform boron dilution should be determined based on the operating conditions.

[0076] Specifically, in operating condition 14, the protection against non-uniform boron dilution will be triggered after RHR exits. Therefore, it is advisable to exit the protection against non-uniform boron dilution before entering operating condition 14. Thus, the control conditions for the protection against non-uniform boron dilution can be determined based on this principle, namely, exiting the protection against non-uniform boron dilution before entering operating condition 14.

[0077] Next, select the characteristic signal.

[0078] Specifically, the unit's downlink process is a continuous cooling and depressurization process, while the unit's uplink process is a continuous heating and depressurization process. Therefore, temperature conditions can be considered to characterize the RHR connection / deactivation status, and further, to characterize the activation / deactivation conditions of the non-uniform boron dilution protection action. The average temperature of the reactor coolant can be selected as a characteristic signal.

[0079] Then, the judgment conditions are determined based on the characteristic signals.

[0080] Specifically, the determination of the judgment conditions for the characteristic signal can refer to the selection of the preset temperature in the steps.

[0081] Finally, the automatic control logic for preventing non-uniform boron dilution is set according to the activation conditions, characteristic signals, and judgment conditions.

[0082] In a preferred embodiment, as shown in Figure 3, it is a logic diagram of the automatic control system for protecting nuclear power plants from non-uniform boron dilution provided by the present invention.

[0083] In this embodiment, the automatic control system for preventing non-uniform boron dilution in the nuclear power plant includes:

[0084] The signal monitoring module 10 is used for real-time monitoring of the reactor coolant system.

[0085] The first logic judgment module 20 is used to determine whether the loss of forced circulation signal, loss of natural circulation signal, and waste heat discharge system disconnection signal are detected. If so, the first logic signal is output.

[0086] The control unit 30 is used to acquire the average temperature of the reactor coolant when it receives the first logic signal, and to control the action of protecting against non-uniform boron dilution based on the average temperature of the reactor coolant.

[0087] Optionally, in this embodiment of the invention, the control unit 30 includes:

[0088] Temperature monitoring module 31 is used to obtain the average temperature of the reactor coolant.

[0089] The comparison module 32 is used to compare the average temperature of the reactor coolant with the preset temperature and output a comparison signal.

[0090] The second logic judgment module 33 is used to output a second logic signal based on the first logic signal and the comparison signal.

[0091] The trigger control module 34 is used to control the action of preventing non-uniform boron dilution protection according to the second logic signal.

[0092] Furthermore, in this embodiment of the invention, the automatic control system for preventing non-uniform boron dilution in nuclear power plants further includes:

[0093] Alarm module 35 is used to output an alarm signal according to the alarm control signal output by the trigger control module after the non-uniform boron dilution protection action is activated;

[0094] The reset module 36 is used to output a reset signal to the trigger control module according to the received reset control signal.

[0095] In this embodiment of the invention, both the first logic judgment module and the second logic judgment module are AND gates (where “&” in Figure 3 represents an AND gate); the trigger control module is an RS flip-flop (where “RS” in Figure 3 represents an RS flip-flop).

[0096] Specifically, the specific coordination and operation process between each unit / module in the automatic control system for preventing non-uniform boron dilution in nuclear power plants can be referred to the above-mentioned automatic control method for preventing non-uniform boron dilution in nuclear power plants, and will not be repeated here.

[0097] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0098] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0099] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0100] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They do not limit the scope of protection of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. An automatic control method for protecting against non-uniform boron dilution in nuclear power plants, characterized in that, Throughout the reactor's operation from power operation to complete unloading, the following steps are performed: real-time monitoring of the reactor coolant system; determination of whether a loss of forced circulation signal, loss of natural circulation signal, or disconnection of the residual heat removal system signal is detected; if so, acquisition of the average temperature of the reactor coolant; and control of non-uniform boron dilution protection actions based on the average temperature of the reactor coolant; wherein, the control of non-uniform boron dilution protection actions based on the average temperature of the reactor coolant includes: determining whether the average temperature of the reactor coolant is greater than a preset temperature; the preset temperature is obtained through the following steps: acquiring the unit's... The following steps are performed:

1. Obtain the downward access temperature of the waste heat removal system during unit descent; 2. Obtain the downward exit temperature of the waste heat removal system during unit ascent; 3. Obtain the upward access temperature of the waste heat removal system during unit ascent; 4. Obtain the upward exit temperature of the waste heat removal system during unit ascent; 5. Analyze the upward access temperature and the upward exit temperature to obtain the upward temperature trend of the waste heat removal system; 6. Analyze the downward access temperature and the downward exit temperature to obtain the downward temperature trend of the waste heat removal system; 7. Analyze the upward and downward temperature trends of the waste heat removal system to obtain the preset temperature.

2. The automatic control method for preventing non-uniform boron dilution protection in nuclear power plants according to claim 1, characterized in that, Also includes: If the average temperature of the reactor coolant is greater than the preset temperature, the protection action against non-uniform boron dilution will be activated. If the average temperature of the reactor coolant is less than or equal to the preset temperature, the protection against non-uniform boron dilution will not be activated.

3. The automatic control method for preventing non-uniform boron dilution protection in nuclear power plants according to claim 1, characterized in that, The process of obtaining the average temperature of the reactor coolant includes: obtaining multiple real-time temperatures of the reactor coolant; preprocessing the multiple real-time temperatures to obtain multiple effective temperatures; and averaging the multiple effective temperatures to obtain the average temperature of the reactor coolant.

4. The automatic control method for preventing non-uniform boron dilution protection in nuclear power plants according to claim 2, characterized in that, The method further includes: after activating the protection action against non-uniform boron dilution, outputting a protection alarm signal to trigger the protection against non-uniform boron dilution.

5. The automatic control method for preventing non-uniform boron dilution protection in nuclear power plants according to claim 2, characterized in that, The method further includes: determining whether a reset control signal is received; if so, performing a reset operation according to the reset control signal.

6. An automatic control system for protecting against non-uniform boron dilution in nuclear power plants, characterized in that, include: The signal monitoring module is used for real-time monitoring of the reactor coolant system; The first logic judgment module is used to determine whether a loss of forced circulation signal, loss of natural circulation signal, or disconnection signal of the residual heat removal system is detected. If so, it outputs a first logic signal. The control unit is used to obtain the average temperature of the reactor coolant when it receives the first logic signal, and to control the non-uniform boron dilution protection action according to the average temperature of the reactor coolant. The control of the non-uniform boron dilution protection action according to the average temperature of the reactor coolant includes: determining whether the average temperature of the reactor coolant is greater than a preset temperature; the preset temperature is obtained through the following steps: obtaining the unit downlink... The following steps are performed: obtaining the downward access temperature of the waste heat removal system; obtaining the downward exit temperature of the waste heat removal system when the unit is moving downwards; obtaining the upward access temperature of the waste heat removal system when the unit is moving upwards; obtaining the upward exit temperature of the waste heat removal system when the unit is moving upwards; analyzing the upward access temperature and the upward exit temperature to obtain the upward temperature change trend of the waste heat removal system; analyzing the downward access temperature and the downward exit temperature to obtain the downward temperature change trend of the waste heat removal system; and analyzing the upward and downward temperature change trends of the waste heat removal system to obtain the preset temperature.

7. The automatic control system for protecting against non-uniform boron dilution in nuclear power plants according to claim 6, characterized in that, The control unit includes: a temperature monitoring module for acquiring the average temperature of the reactor coolant; a comparison module for comparing the average temperature of the reactor coolant with a preset temperature and outputting a comparison signal; a second logic judgment module for outputting a second logic signal based on the first logic signal and the comparison signal; and a trigger control module for controlling the action of preventing non-uniform boron dilution protection based on the second logic signal.

8. The automatic control system for protecting against non-uniform boron dilution in nuclear power plants according to claim 7, characterized in that, Also includes: An alarm module is used to output an alarm signal according to the alarm control signal output by the trigger control module after the non-uniform boron dilution protection action is activated; a reset module is used to output a reset signal to the trigger control module according to the received reset control signal.

9. The automatic control system for protecting against non-uniform boron dilution in nuclear power plants according to claim 7, characterized in that, Both the first logic judgment module and the second logic judgment module are AND gates; the trigger control module is an RS flip-flop.

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