A method and system for automatically controlling a ventilation system of a nuclear power plant based on radon concentration monitoring

Abstract

This invention relates to an automatic control method and system for a nuclear power plant ventilation system based on radon concentration monitoring. The method presets a warning threshold, an alarm threshold, a recovery stabilization time, a rapid rise rate threshold, and a trigger quantity. It acquires instantaneous radon concentration values ​​collected by multiple radon meters at different monitoring locations and determines the moving average and concentration rise rate based on continuous sampling data. For each radon meter, a first over-threshold state, a second over-threshold state, and a rapid rise state are established. When the number of first over-threshold states reaches the trigger quantity but the second-level linkage condition is not met, a first-level linkage command is generated. When the number of second over-threshold states reaches the trigger quantity or a rapid rise state exists, a second-level linkage command is generated and an alarm is triggered. After each state is cleared and stabilized, normal ventilation resumes. Thus, when the over-threshold is continuously exceeded, linkage is determined based on the number of states at multiple measuring points; when there is a rapid local rise, the second-level linkage is triggered through the rapid rise state, making the ventilation intensity correspond to the concentration change state and forming a control record.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant radiation safety and environmental control technology, and in particular to an automatic control method and system for a nuclear power plant ventilation system based on radon concentration monitoring. Background Technology

[0002] During the operation of a nuclear power plant, areas such as fuel buildings, waste treatment buildings, and underground corridors may involve the storage, transfer, or treatment of naturally occurring radioactive materials. The building structure, soil environment, ventilation system, and local negative pressure conditions within these buildings can all affect the diffusion and accumulation of radon and its decay products. These areas are typically equipped with mechanical ventilation systems and radon concentration monitoring equipment can be installed according to the plant environment and radiation safety management requirements to monitor changes in radon concentration in the air inside the plant.

[0003] In existing nuclear power plant radon management, fixed or portable radon meters are typically used to monitor radon concentrations within the plant periodically or continuously, displaying, alarming, or alerting when the concentration reaches a set level. The operation of the ventilation system is usually adjusted based on manual operation, preset operating procedures, routine ventilation needs, or other environmental monitoring parameters. When radon concentrations rise, methods such as increasing fan power, increasing fresh air volume, or extending ventilation time are generally used to reduce radon concentrations within the plant.

[0004] However, in the case of multiple monitoring locations coexisting in nuclear power plant buildings, where the location of radon accumulation is not fixed and the rate of concentration change may vary, how to perform timely and graded automatic control of the ventilation system based on the radon concentration change status of multiple monitoring locations is a technical problem that needs to be solved in the radon ventilation control of nuclear power plant buildings. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to automatically control the ventilation system in stages based on the radon concentration changes at multiple monitoring locations in a nuclear power plant building where there are multiple radon monitoring locations, the radon accumulation locations are not fixed, and the concentration change rates are different.

[0006] The technical solution of this invention to solve the above-mentioned technical problems is as follows: An automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring, comprising the following steps: S1: Preset control parameters, the control parameters include a first warning threshold, a second alarm threshold, a first duration, a second duration, a recovery stabilization time, a rapid rise rate threshold, and a trigger number, the first warning threshold being less than the second alarm threshold, and the trigger number being an integer not less than two units; S2: Obtain the instantaneous radon concentration values ​​collected by multiple radon detectors at different monitoring locations, and determine the moving average value and concentration rise rate based on the continuous sampling data of each radon detector; S3: For each radon meter, a status flag is generated, wherein if the moving average value continuously exceeds the first warning threshold and reaches the first duration, it is recorded as the first threshold exceedance state; if the moving average value continuously exceeds the second alarm threshold and reaches the second duration, it is recorded as the second threshold exceedance state; if the concentration rise rate exceeds the rapid rise rate threshold, it is recorded as the rapid rise state. S4: When the number of radon detectors in the first over-threshold state is not less than the number of triggers, and the number of radon detectors in the second over-threshold state is less than the number of triggers and there are no radon detectors in the rapid rise state, a first-level linkage command is generated, and the ventilation system is controlled to enter the first ventilation mode. S5: When the number of radon detectors in the second over-threshold state is not less than the number of triggers, or when there are radon detectors in the rapid rise state, a second-level linkage command is generated, and the ventilation system is controlled to enter the second ventilation mode and an alarm is triggered. The ventilation intensity of the second ventilation mode is higher than that of the first ventilation mode. S6: When all radon detectors are no longer in the first over-threshold state, the second over-threshold state, or the rapid rise state, and have reached a stable recovery time, a recovery command is generated, and the ventilation system is controlled to return to normal ventilation status.

[0007] This invention also provides an automatic control system for a nuclear power plant ventilation system based on radon concentration monitoring, used to execute the aforementioned automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring. The system includes a radon monitoring module, a data processing and logic judgment unit, a ventilation system control interface, a human-machine interaction and alarm unit, and a data recording unit. The radon monitoring module includes multiple radon detectors distributed at different monitoring locations within the nuclear power plant building. These detectors are used to collect instantaneous radon concentration values ​​at their respective monitoring locations. The data processing and logic judgment unit is communicatively connected to the radon monitoring module and is used to receive the instantaneous radon concentration values ​​from each detector, determine the sliding average value and concentration rise rate corresponding to each detector, and generate status flags for each detector. These status flags include a first threshold state, a second threshold state, and a rapid rise state. The data processing and logic judgment unit also... The system is used to generate first-level linkage commands, second-level linkage commands, or recovery commands based on the status flags and trigger counts; the ventilation system control interface is connected to the data processing and logic judgment unit and the ventilation system respectively, and is used to control the operating status of the ventilation system according to the first-level linkage commands, second-level linkage commands, or recovery commands; the human-machine interaction and alarm unit is connected to the data processing and logic judgment unit, and is used to display the radon concentration data of each radon meter, the operating status of the ventilation system, and alarm information; the data recording unit is connected to the data processing and logic judgment unit, and is used to record the radon concentration data, status flags, linkage commands, operating status of the ventilation system, and alarm information of each radon meter.

[0008] The beneficial effects of this invention are as follows: This invention uses multiple radon detectors to respectively form a first over-threshold state, a second over-threshold state, and a rapid rise state, and determines the linkage level of the ventilation system based on the number of radon detectors in the corresponding state and the presence of a rapid rise state. Through the above processing, in the case of continuous over-threshold conditions, linkage judgment can be made based on the number of radon detectors in the corresponding over-threshold state; in the case of local rapid rise, a second-level linkage can be triggered through a rapid rise state, enabling the system to distinguish between continuous rise states and local rapid rise states in multiple monitoring locations, and generate first-level linkage commands, second-level linkage commands, or recovery commands according to different state combinations.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, the trigger quantity is two units; when the number of radon detectors in the first over-threshold state reaches two units, the quantity condition for the first-level linkage instruction is met; when the number of radon detectors in the second over-threshold state reaches two units, the quantity condition for the second-level linkage instruction is met.

[0011] The beneficial effects of adopting the above-mentioned further scheme are: by limiting the number of triggers to two, the linkage judgment under continuous over-threshold conditions is based on the occurrence of the corresponding state at no less than two monitoring locations; at the same time, in the case of local rapid rise, a secondary linkage can still be triggered through the rapid rise state. Therefore, the influence of local abnormal measuring points can be weakened when using only the average value of all measuring points as the judgment basis, making the ventilation linkage judgment more suitable for factory conditions where multiple monitoring locations coexist and the location of radon gas accumulation is not fixed.

[0012] Furthermore, the radon detector outputs the instantaneous radon concentration value at one data point per minute; the moving average value is calculated based on three consecutive sampling data from the same radon detector; and the concentration rise rate is determined based on the difference in radon concentration at adjacent sampling times of the same radon detector and the corresponding sampling time interval.

[0013] The beneficial effects of adopting the above-mentioned further scheme are as follows: A moving average is determined by using three consecutive sampling data points, allowing the first and second exceedance states to reflect continuous concentration changes at the same monitoring location; the rate of concentration increase is determined by the difference in radon concentration between adjacent sampling times and the corresponding sampling time interval, allowing the rapid increase state to reflect the speed of concentration changes at the same monitoring location. Therefore, the system can identify both continuously rising and rapidly rising concentration changes, providing corresponding judgment criteria for different levels of ventilation linkage.

[0014] Furthermore, when the sliding average value of any radon meter falls below the first warning threshold, the first over-threshold state of the radon meter is lifted; when the sliding average value of any radon meter falls below the second alarm threshold, the second over-threshold state of the radon meter is lifted; when the concentration rise rate of any radon meter no longer exceeds the rapid rise rate threshold, the rapid rise state of the radon meter is lifted.

[0015] The beneficial effect of adopting the above-mentioned further scheme is that by clarifying the release conditions of the first over-threshold state, the second over-threshold state, and the rapid rise state, the status flags of each radon detector can be updated according to the concentration change. Therefore, after each radon detector's status is released and stabilizes for the recovery time, the ventilation system can resume normal ventilation, forming a closed loop that connects state entry, state release, and recovery control.

[0016] Furthermore, the first ventilation mode includes increasing the frequency of the ventilation system's fan and adjusting the opening of the fresh air valve; the second ventilation mode includes controlling the ventilation system to operate at full power and sending an alarm trigger signal to the human-machine interaction and alarm unit; the normal ventilation state is when the ventilation system operates at a preset normal air volume.

[0017] The beneficial effect of adopting the above-mentioned further scheme is that by corresponding the first ventilation mode, the second ventilation mode, and the normal ventilation state to different ventilation intensities, the ventilation system can execute different intensities of control according to changes in the state level. When the number of radon detectors in the first over-threshold state meets the condition but has not yet met the secondary linkage condition, the system enters the first ventilation mode; when the conditions for the second over-threshold state or the rapid rise state are met, the system enters the second ventilation mode and triggers an alarm, thereby forming a graded ventilation control corresponding to the radon concentration state level.

[0018] Furthermore, the first warning threshold is 150 Bq / m³, the second alarm threshold is 190 Bq / m³, the first duration is 20 minutes, the second duration is 10 minutes, and the recovery stabilization time is 30 minutes; the normal ventilation state corresponds to 30% air volume, the first ventilation mode corresponds to 70% air volume, and the second ventilation mode corresponds to 100% air volume.

[0019] The beneficial effect of adopting the above-mentioned further solution is that by setting different concentration thresholds, durations, and airflow levels, the warning, alarm, and recovery states correspond to different ventilation control results. Therefore, under the operating conditions of this embodiment, the system can switch from normal ventilation to the first ventilation mode or the second ventilation mode according to the concentration state, and resume normal ventilation after the state is resolved and stabilized, avoiding the use of the same ventilation intensity under different states.

[0020] Furthermore, when generating first-level linkage commands, second-level linkage commands, or recovery commands, the trigger time, radon meter number, instantaneous radon concentration value, sliding average value, concentration rise rate, status flag, linkage command type, ventilation system operating status, and alarm information are recorded.

[0021] The beneficial effect of adopting the above-mentioned further solution is that by recording the corresponding information of the radon meter number, concentration data, status flags, linkage commands, and ventilation system operating status, each ventilation linkage can be correlated with the triggering measurement point, triggering status, and executed action. Therefore, the concentration changes and control process at the time of ventilation linkage can be traced based on the recorded data, providing a data basis for the verification and adjustment of control parameters. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the automatic control system for a nuclear power plant ventilation system based on radon concentration monitoring, as described in this invention. Figure 2 This is a flowchart illustrating the automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring, as described in this invention. Figure 3 This is a schematic diagram of radon concentration and ventilation response under the first-level linkage scenario of the present invention; Figure 4 This is a schematic diagram of radon concentration and ventilation response under the two-stage linkage scenario of the present invention. Detailed Implementation

[0023] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0024] In this invention, a radon meter refers to a monitoring device used to continuously collect radon concentration data at a corresponding monitoring location, preferably a wall-mounted continuous radon meter. The instantaneous radon concentration value refers to the radon concentration value output by the radon meter at the current sampling time. The moving average value refers to the average concentration value obtained from continuous sampling data of the same radon meter. The concentration rise rate refers to the rate of concentration change determined by the difference in radon concentration between adjacent sampling times of the same radon meter and the corresponding sampling time interval. The first threshold state, the second threshold state, and the rapid rise state are all status flags formed by the data processing and logic judgment unit based on the data from each radon meter. Specifically, the first threshold state corresponds to the moving average value continuously exceeding the first warning threshold and reaching a first duration; the second threshold state corresponds to the moving average value continuously exceeding the second alarm threshold and reaching a second duration; and the rapid rise state corresponds to the concentration rise rate exceeding the rapid rise rate threshold. The trigger quantity refers to the number of radon meters used to determine whether to generate a corresponding linkage command.

[0025] Example 1 like Figure 2As shown, this embodiment provides an automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring. This method can be applied to areas requiring radon concentration monitoring and ventilation-linked control, such as fuel rooms, waste treatment rooms, and underground corridors in nuclear power plants. The method can be executed by the data processing and logic judgment unit of the plant radiation monitoring system, or by a separately configured programmable logic controller (PLC). The method operates continuously according to the sampling cycle of the radon meter, updating the status flags and ventilation control commands each time new radon concentration data is obtained.

[0026] S1: Preset control parameters.

[0027] In this embodiment, the data processing and logic judgment unit presets a first warning threshold, a second alarm threshold, a first duration, a second duration, a recovery stabilization time, a rapid rise rate threshold, and a trigger quantity. The first warning threshold is less than the second alarm threshold. The first warning threshold is used to form a first over-threshold state, the second alarm threshold is used to form a second over-threshold state, and the rapid rise rate threshold is used to form a rapid rise state. The trigger quantity is an integer not less than two units, used to determine whether the number of radon detectors in the corresponding state meets the linkage condition.

[0028] In one specific implementation, the first warning threshold is 150 Bq / m³, the second alarm threshold is 190 Bq / m³, the first duration is 20 minutes, the second duration is 10 minutes, the recovery stabilization time is 30 minutes, and the triggering quantity is two units. These parameters can be pre-programmed into the programmable logic controller or the radiation monitoring system computer and used as engineering configuration parameters for subsequent status judgment and ventilation linkage control. The rapid rise rate threshold is a pre-set engineering configuration parameter used to determine whether the concentration rise rate has reached a rapid rise state.

[0029] S2: Collect radon concentration data and determine the moving average and concentration rise rate.

[0030] In this embodiment, multiple radon detectors are installed inside the nuclear power plant building. These detectors are positioned at various monitoring locations, such as the four corners of the building, the center, and at least some of the pre-determined ventilation dead zones. Each radon detector continuously collects the instantaneous radon concentration value at its corresponding monitoring location and sends this value to the data processing and logic judgment unit.

[0031] In one specific implementation, five radon detectors are installed at the four corners and the center of the nuclear power plant's fuel storage building. Each radon detector transmits the instantaneous radon concentration value to the data processing and logic judgment unit via a 4-20mA analog signal line or industrial Ethernet. The radon detectors can be wall-mounted radon measuring devices capable of continuously outputting radon concentration data, such as continuous radon measuring devices using electrostatic collection methods, or other radon measuring devices capable of continuously outputting radon concentration data.

[0032] In one specific implementation, the radon detector outputs the instantaneous radon concentration value at one data point per minute. The data processing and logic judgment unit stores the continuous sampling data of each radon detector according to its serial number. For the same radon detector, the data processing and logic judgment unit determines the moving average value based on three consecutive sampling data points, and determines the concentration rise rate based on the difference in radon concentration at adjacent sampling times and the corresponding sampling time interval; when the sampling period is 1 minute, the concentration rise rate corresponds to the radon concentration increment per unit time.

[0033] In the above processing, the moving average is used to reflect the concentration change status of the same radon meter during continuous sampling, and the concentration rise rate is used to reflect the rate of concentration increase of the same radon meter between adjacent sampling times. The data processing and logic judgment unit performs the above processing for each radon meter, and uses the statistical results of the status flags of each radon meter as the basis for linkage judgment.

[0034] S3: Generate status indicators for each radon detector.

[0035] The data processing and logic judgment unit performs status judgment on each radon detector.

[0036] For any radon detector, when the moving average value corresponding to the radon detector continuously exceeds the first warning threshold and reaches the first duration, the data processing and logic judgment unit records the radon detector as a first over-threshold state. This state is used to characterize the situation where the radon value at the monitoring location continuously rises above the first warning threshold.

[0037] For any radon detector, when the sliding average value corresponding to the detector continuously exceeds the second alarm threshold and reaches the second duration, the data processing and logic judgment unit records the radon detector as being in a second over-threshold state. This state is used to characterize a situation where the radon level at the monitoring location continuously rises above the second alarm threshold.

[0038] For any radon detector, when the rate of increase in concentration corresponding to that detector exceeds the rapid increase rate threshold, the data processing and logic judgment unit records that detector as being in a rapid increase state. The rapid increase state is judged separately from the first and second threshold states; when a radon detector is in a rapid increase state, even if the number of detectors in the second threshold state has not yet reached the trigger number, it can still be used as the basis for subsequent secondary linkage judgments.

[0039] In this embodiment, after the data processing and logic judgment unit generates a status flag for each radon detector, it counts the number of radon detectors in the first threshold state, the number of radon detectors in the second threshold state, and whether there are any radon detectors in a rapid increase state. When the trigger quantity is set to two, for continuous threshold exceedance, the linkage judgment is based on the number of radon detectors in the corresponding threshold exceedance state; for local rapid increase, the linkage judgment retains the secondary linkage trigger path of the rapid increase state.

[0040] During continuous operation, if the sliding average value of a radon meter falls below the corresponding threshold, the first or second over-threshold state corresponding to that radon meter is lifted; if the concentration rise rate of that radon meter no longer exceeds the rapid rise rate threshold, the rapid rise state corresponding to that radon meter is lifted. The data processing and logic judgment unit updates the status flags of each radon meter in the next sampling cycle.

[0041] S4: Determine the first-level linkage and execute the first ventilation mode.

[0042] The data processing and logic judgment unit counts the number of radon detectors in the first over-threshold state. When the number of radon detectors in the first over-threshold state is not less than the trigger number, and the number of radon detectors in the second over-threshold state is less than the trigger number, and there are no radon detectors in the rapid rise state, the data processing and logic judgment unit generates a first-level linkage instruction.

[0043] The first-level linkage command is sent to the ventilation system via the ventilation system control interface. The ventilation system enters the first ventilation mode based on the command. In the first ventilation mode, the ventilation system can increase the fan frequency and adjust the opening of the fresh air valve. Through this process, the ventilation system increases the ventilation intensity compared to the normal ventilation state, but does not enter the full-power operation state corresponding to the second ventilation mode.

[0044] In one specific implementation, the normal ventilation state corresponds to 30% air volume, and the first ventilation mode corresponds to 70% air volume. When the data processing and logic judgment unit determines that the first-level linkage condition is met, the ventilation system switches from 30% air volume to 70% air volume.

[0045] S5: Determine the secondary linkage and execute the second ventilation mode.

[0046] The data processing and logic judgment unit counts the number of radon detectors in the second over-threshold state and determines whether there are any radon detectors in the rapid rise state. When the number of radon detectors in the second over-threshold state is not less than the trigger number, or when there are any radon detectors in the rapid rise state, the data processing and logic judgment unit generates a second-level linkage instruction.

[0047] The secondary linkage command is sent to the ventilation system via the ventilation system control interface. The ventilation system then enters the second ventilation mode based on the command and triggers an alarm. The ventilation intensity in the second ventilation mode is higher than that in the first ventilation mode. In one specific embodiment, the second ventilation mode includes controlling the ventilation system to operate at full power and sending an alarm trigger signal to the human-machine interface and alarm unit, causing the unit to output audible and visual alarm information.

[0048] In one specific implementation, the second ventilation mode corresponds to 100% airflow. When the number of radon detectors in the second over-threshold state reaches two, or when any radon detector is in a rapid increase state, the data processing and logic judgment unit generates a secondary linkage command, and the ventilation system switches to 100% airflow operation. When there are radon detectors in a rapid increase state, the data processing and logic judgment unit can generate the secondary linkage command without waiting for the number of radon detectors in the second over-threshold state to reach the trigger number.

[0049] S6: Determine the recovery conditions and restore normal ventilation.

[0050] After the ventilation system enters the first or second ventilation mode, the data processing and logic judgment unit continues to receive the instantaneous radon concentration values ​​of each radon meter and continuously updates the sliding average value, concentration rise rate and status flag of each radon meter.

[0051] In this embodiment, "none of the radon detectors are in the first over-threshold state, the second over-threshold state, or the rapid rise state" means that the sliding average value of each radon detector has fallen back below the first warning threshold, and the concentration rise rate of each radon detector has not exceeded the rapid rise rate threshold. Once all radon detectors are no longer in the above states and have stabilized for the required recovery time, the data processing and logic judgment unit generates a recovery command. The recovery command is sent to the ventilation system via the ventilation system control interface, and the ventilation system restores normal ventilation status according to the recovery command.

[0052] In one specific implementation, the recovery stabilization time is 30 minutes, corresponding to 30% airflow in normal ventilation mode. That is, after all radon detector status flags are deactivated and the system has stabilized for 30 minutes, the ventilation system resumes operation at 30% airflow. During the recovery stabilization time, if any radon detector re-enters the first over-threshold state, the second over-threshold state, or a rapid rise state, the data processing and logic judgment unit continues to re-determine the primary or secondary linkage conditions according to the corresponding state.

[0053] During the operation of the above method, when the data processing and logic judgment unit generates first-level linkage instructions, second-level linkage instructions, or recovery instructions, it writes the trigger time, radon meter number, instantaneous radon concentration value, moving average value, concentration rise rate, status flag, linkage instruction type, ventilation system operating status, and alarm information into the data recording unit. The data recording unit can be located in the storage area of ​​the programmable logic controller (PLC) or in the host computer database that is communicatively connected to the PLC.

[0054] In an illustrative operating scenario, radon gas is released in a localized area of ​​the plant. Radon detectors near the area first detect an increase in concentration. The data processing and logic judgment unit determines the corresponding linkage level based on the status flags and trigger counts of each radon detector.

[0055] Combination Figure 3 In the first-level linkage scenario, the radon concentration of a representative radon detector or a triggered radon detector can slowly rise to around 160 Bq / m³ and meet the first duration requirement. When the number of radon detectors meeting the first threshold condition reaches the trigger requirement, and the second-level linkage condition is not met, the data processing and logic judgment unit generates a first-level linkage command, and the ventilation system enters the first ventilation mode, with the ventilation volume ratio increasing from 0.3 to 0.7. As ventilation intensifies, the radon concentration decreases and stabilizes below the first warning threshold after reaching a recovery stabilization time. The ventilation system then returns to normal ventilation mode, and the ventilation volume ratio returns from 0.7 to 0.3.

[0056] Combination Figure 4 In a two-stage linkage scenario, the radon concentration of a representative radon detector or a trigger radon detector can rise from near the first warning threshold to near the second alarm threshold within a short period of time, reaching approximately 195 Bq / m³. When a radon detector is in a state of rapid increase, the data processing and logic judgment unit generates a two-stage linkage command, the ventilation system enters the second ventilation mode and triggers an alarm, and the ventilation volume ratio increases from 0.3 to 1.0. Figure 4 This is used to represent a response scenario where a rapid rise in the state triggers a secondary linkage; when the number of radon detectors in the second over-threshold state reaches the trigger number, the data processing and logic judgment unit also generates a secondary linkage instruction.

[0057] In a complete control cycle, multiple radon detectors first send instantaneous radon concentration values ​​from different monitoring locations to the data processing and logic judgment unit. The data processing and logic judgment unit updates the continuous sampling data of each radon detector according to its serial number, and determines the sliding average value and concentration rise rate of each detector accordingly. Subsequently, it establishes the first over-threshold state, second over-threshold state, and rapid rise state for each radon detector, counts the number of detectors in each corresponding state, and generates a first-level linkage command, a second-level linkage command, or a recovery command based on the presence of a rapid rise state. The ventilation system control interface sends the corresponding command to the ventilation system, causing it to enter the first ventilation mode, the second ventilation mode, or normal ventilation state. Simultaneously, the human-machine interface and alarm unit displays radon concentration data, ventilation system operating status, and alarm information, while the data recording unit records the data and commands corresponding to this control cycle. If the next sampling cycle begins, the instantaneous radon concentration values ​​of each radon detector are reacquired, and the above state judgment and ventilation linkage process continues.

[0058] Example 2 like Figure 1 As shown, this embodiment provides an automatic control system for a nuclear power plant ventilation system based on radon concentration monitoring. This system is used to execute the automatic control method in Embodiment 1 and includes a radon monitoring module, a data processing and logic judgment unit, a ventilation system control interface, a ventilation system, a human-machine interaction and alarm unit, and a data recording unit.

[0059] The radon monitoring module includes multiple radon detectors distributed at different monitoring locations within the nuclear power plant building. Each radon detector collects instantaneous radon concentration values ​​at its corresponding monitoring location and transmits these values ​​to a data processing and logic judgment unit. In one specific embodiment, the multiple radon detectors are arranged at at least some of the four corners, the center, and predetermined ventilation dead zones of the nuclear power plant building. Specifically, there may be five radon detectors, respectively located at the four corners and the center of the building.

[0060] The data processing and logic judgment unit is communicatively connected to the radon monitoring module. This unit receives instantaneous radon concentration values ​​from each radon meter, determines the corresponding sliding average value and concentration rise rate for each meter, and generates status flags for each meter. These status flags include a first threshold exceedance state, a second threshold exceedance state, and a rapid rise state. The unit also generates first-level linkage commands, second-level linkage commands, or recovery commands based on the status flags and the number of triggers.

[0061] In one specific implementation, the data processing and logic judgment unit includes a programmable logic controller (PLC). Multiple radon detectors are connected to the PLC via 4-20mA analog signal lines or industrial Ethernet. The PLC receives the instantaneous radon concentration values ​​output by the radon detectors, saves continuous sampling data according to the radon detector number, and performs functions such as determining the sliding average value, determining the concentration rise rate, generating status flags, counting trigger quantities, and generating linkage instructions based on internally preset control parameters.

[0062] The ventilation system control interface is connected to both the data processing and logic judgment unit and the ventilation system. It is used to control the operating status of the ventilation system based on primary linkage commands, secondary linkage commands, or recovery commands. The ventilation system control interface can use hard-wired signal contacts or a communication protocol gateway such as Modbus or Profibus to transmit primary linkage commands, secondary linkage commands, or recovery commands to the ventilation system's fan frequency converter control loop and fresh air valve control loop.

[0063] In one specific implementation, the ventilation system control interface includes a fan frequency converter control interface and a fresh air valve control interface. The fan frequency converter control interface is connected to the fan frequency converter control loop of the ventilation system, and the fresh air valve control interface is connected to the fresh air valve control loop of the ventilation system. Based on the first-level linkage command, the data processing and logic judgment unit adjusts the fan frequency converter frequency and the fresh air valve opening through the fan frequency converter control interface and the fresh air valve control interface, respectively. Based on the second-level linkage command, the data processing and logic judgment unit controls the ventilation system to operate at full power through the fan frequency converter control interface and outputs audible and visual alarm information through the human-machine interaction and alarm unit. Based on the recovery command, the data processing and logic judgment unit controls the ventilation system to return to normal ventilation state through the ventilation system control interface.

[0064] The human-machine interface and alarm unit is connected to the data processing and logic judgment unit, and is used to display the radon concentration curves of each radon meter, the operating status of the ventilation system, linkage records, and alarm information in the control room. After the secondary linkage command is generated, the human-machine interface and alarm unit receives the alarm trigger signal and outputs audible and visual alarm information.

[0065] The data recording unit is connected to the data processing and logic judgment unit and is used to record radon concentration data, status flags, linkage commands, ventilation system operating status, and alarm information from each radon detector. The data recorded by the data recording unit can be used to view the triggering of radon detectors, triggering status, linkage command types, and ventilation system execution status within a certain control cycle.

[0066] In this embodiment, the radon monitoring module provides instantaneous radon concentration values ​​at multiple monitoring locations. The data processing and logic judgment unit generates status flags and control commands based on these instantaneous radon concentration values. The ventilation system control interface transmits the control commands to the ventilation system. The human-machine interface and alarm unit displays the status and alarm information, and the data recording unit saves the control process data. Through this structure, the modules can cooperate to complete the processes of radon concentration monitoring, status judgment, ventilation linkage, and data recording within the nuclear power plant building.

Claims

1. An automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring, characterized in that, Includes the following steps: S1: Preset control parameters, the control parameters include a first warning threshold, a second alarm threshold, a first duration, a second duration, a recovery stabilization time, a rapid rise rate threshold, and a trigger number, the first warning threshold being less than the second alarm threshold, and the trigger number being an integer not less than two units; S2: Obtain the instantaneous radon concentration values ​​collected by multiple radon detectors at different monitoring locations, and determine the moving average value and concentration rise rate based on the continuous sampling data of each radon detector; S3: For each radon meter, a status flag is generated, wherein if the moving average value continuously exceeds the first warning threshold and reaches the first duration, it is recorded as the first threshold exceedance state; if the moving average value continuously exceeds the second alarm threshold and reaches the second duration, it is recorded as the second threshold exceedance state; if the concentration rise rate exceeds the rapid rise rate threshold, it is recorded as the rapid rise state. S4: When the number of radon detectors in the first over-threshold state is not less than the number of triggers, and the number of radon detectors in the second over-threshold state is less than the number of triggers and there are no radon detectors in the rapid rise state, a first-level linkage command is generated, and the ventilation system is controlled to enter the first ventilation mode. S5: When the number of radon detectors in the second over-threshold state is not less than the number of triggers, or when there are radon detectors in the rapid rise state, a second-level linkage command is generated, and the ventilation system is controlled to enter the second ventilation mode and an alarm is triggered. The ventilation intensity of the second ventilation mode is higher than that of the first ventilation mode. S6: When all radon detectors are no longer in the first over-threshold state, the second over-threshold state, or the rapid rise state, and have reached a stable recovery time, a recovery command is generated, and the ventilation system is controlled to return to normal ventilation status.

2. The automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring according to claim 1, characterized in that, The trigger quantity is two units; when the number of radon detectors in the first over-threshold state reaches two units, the quantity condition for the first-level linkage instruction is met; when the number of radon detectors in the second over-threshold state reaches two units, the quantity condition for the second-level linkage instruction is met.

3. The automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring according to claim 1, characterized in that, The radon meter outputs the instantaneous radon concentration value at one data point per minute; the moving average value is calculated based on three consecutive sampling data from the same radon meter; the concentration rise rate is determined based on the difference in radon concentration at adjacent sampling times of the same radon meter and the corresponding sampling time interval.

4. The automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring according to claim 1, characterized in that, When the sliding average value of any radon meter falls below the first warning threshold, the first over-threshold state of the radon meter is lifted; when the sliding average value of any radon meter falls below the second alarm threshold, the second over-threshold state of the radon meter is lifted; when the concentration rise rate of any radon meter no longer exceeds the rapid rise rate threshold, the rapid rise state of the radon meter is lifted.

5. The automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring according to claim 1, characterized in that, The first ventilation mode includes increasing the frequency of the ventilation system's fan and adjusting the opening of the fresh air valve; the second ventilation mode includes controlling the ventilation system to operate at full power and sending an alarm trigger signal to the human-machine interface and alarm unit; the normal ventilation state is when the ventilation system operates at a preset normal air volume.

6. The automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring according to claim 1, characterized in that, The first warning threshold is 150 Bq / m³, the second alarm threshold is 190 Bq / m³, the first duration is 20 minutes, the second duration is 10 minutes, and the recovery stabilization time is 30 minutes; the normal ventilation state corresponds to 30% air volume, the first ventilation mode corresponds to 70% air volume, and the second ventilation mode corresponds to 100% air volume.

7. The automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring according to claim 1, characterized in that, When generating a first-level linkage command, a second-level linkage command, or a recovery command, record the trigger time, radon meter number, instantaneous radon concentration value, sliding average value, concentration rise rate, status flag, linkage command type, ventilation system operating status, and alarm information.

8. An automatic control system for a nuclear power plant ventilation system based on radon concentration monitoring, used to execute the automatic control method for a nuclear power plant ventilation system based on radon concentration monitoring as described in any one of claims 1 to 7, characterized in that, include: The radon monitoring module includes multiple radon detectors distributed at different monitoring locations within the nuclear power plant building. The radon detectors are used to collect instantaneous values ​​of radon concentration at the corresponding monitoring locations. The data processing and logic judgment unit is communicatively connected to the radon monitoring module. It is used to receive the instantaneous radon concentration values ​​from each radon detector, determine the sliding average value and concentration rise rate corresponding to each radon detector, and form a status flag for each radon detector. The status flag includes a first threshold state, a second threshold state, and a rapid rise state. The data processing and logic judgment unit is also used to generate a first-level linkage command, a second-level linkage command, or a recovery command based on the status flag and the number of triggers. The ventilation system control interface is connected to the data processing and logic judgment unit and the ventilation system respectively, and is used to control the operating status of the ventilation system according to the first-level linkage command, the second-level linkage command or the recovery command. The human-computer interaction and alarm unit is connected to the data processing and logic judgment unit and is used to display the radon concentration data of each radon meter, the operating status of the ventilation system and alarm information; The data recording unit, connected to the data processing and logic judgment unit, is used to record the radon concentration data, status flags, linkage commands, ventilation system operating status, and alarm information of each radon meter.

9. The automatic control system for a nuclear power plant ventilation system based on radon concentration monitoring according to claim 8, characterized in that, The data processing and logic judgment unit includes a programmable logic controller; multiple radon detectors are connected to the programmable logic controller via 4-20mA analog signal lines or industrial Ethernet; the multiple radon detectors are arranged at least some of the four corners, the center, and predetermined ventilation dead zones of the nuclear power plant building.

10. The automatic control system for a nuclear power plant ventilation system based on radon concentration monitoring according to claim 8, characterized in that, The ventilation system control interface includes a fan frequency converter control interface and a fresh air valve control interface; the fan frequency converter control interface is connected to the fan frequency converter control loop of the ventilation system, and the fresh air valve control interface is connected to the fresh air valve control loop of the ventilation system; the data processing and logic judgment unit adjusts the fan frequency converter frequency and the fresh air valve opening through the fan frequency converter control interface and the fresh air valve control interface respectively according to the first-level linkage command, and controls the ventilation system to run at full power through the fan frequency converter control interface according to the second-level linkage command, and outputs audible and visual alarm information through the human-machine interaction and alarm unit.

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