JP2021056006A - Nuclear reactor measurement system, and soundness check method of nuclear reactor measurement system - Google Patents

Abstract

To make it possible to check soundness of sensors such as a radiation detector, gas concentration detector and the like to be installed in a nuclear reactor containment, in which the sensors are used in monitoring when an accident happens, but not used in monitoring during a normal operation of plants.SOLUTION: A nuclear reactor measurement system comprises: a control unit 12 that is provided in an emergency control chamber monitoring a nuclear reactor at a time of abnormality of the nuclear reactor; and a plurality of sensors that are provided inside a nuclear reactor containment 53, and transmit a measurement signal to the control unit 12. The control unit 12 provided in the emergency control chamber monitoring the nuclear reactor at a time of abnormality of the nuclear reactor is provided with a database 32 that stores analysis data obtained by analyzing behaviors at a time of an operation and accident of a nuclear power plant 51 for each possible phenomenon pattern in the nuclear power plant 51, and is configured to determine soundness of the plurality of sensors on the basis of the measurement data received from the sensor installed inside the nuclear reactor containment 53, and the analysis data.SELECTED DRAWING: Figure 1

Description

The present invention relates to a nuclear reactor measurement system and a method for confirming the soundness of a nuclear reactor measurement system.

In the reactor containment vessel of a nuclear power plant, multiple types of parameters such as dose rate and gas concentration, temperature and pressure are measured by sensors in order to confirm the soundness of the reactor and grasp the state. .. For example, the signal measured by the radiation detector installed in the containment vessel penetration or the gas detector installed in the reactor containment vessel is transmitted to the central control room and converted into the dose rate and gas concentration by the signal processing device. And monitor.

JP-A-2017-83190

In order to improve the safety of nuclear power plants, it is necessary to newly install a radiation detector that measures the dose rate in the reactor containment vessel and a gas detector that measures the gas concentration as equipment for dealing with specific serious accidents. ing. Since the sensor provided as the equipment for dealing with specific serious accidents is not used for monitoring during normal operation, it is assumed that the sensor will not be operated during normal operation of the nuclear power plant but will be operated during an accident.

On the other hand, since these sensors are installed in the reactor containment vessel, the sensors cannot be collected, replaced, inspected, etc. during plant operation or accident. Therefore, there is a need for a method for determining the soundness of these sensors, which is important in the event of an accident.

An embodiment of the present invention has been made to solve the above-mentioned problems, and is used for monitoring a nuclear power plant in the event of an accident. Sensors such as a radiation detector and a gas concentration detector installed in a reactor containment vessel. The purpose is to provide a nuclear reactor measurement system that can confirm the soundness of the reactor.

In order to achieve the above object, the reactor measurement system according to the embodiment is installed separately from the nuclear power plant, and has a control unit provided in an emergency control room that monitors the reactor in the event of a reactor abnormality, and a reactor. A plurality of first sensors installed inside the containment vessel and transmitting measurement signals to the control unit are provided, and the control unit is used for each event pattern that can occur in the nuclear power plant during operation of the nuclear power plant and accidents. A database that stores analysis data that analyzes the behavior of time, and
A determination unit for determining the soundness of the plurality of first sensors based on the measurement signals received from the plurality of first sensors and the analysis data is provided.

Further, the method for confirming the soundness of the reactor measurement system according to the embodiment is connected to a control unit provided in an emergency control room that is installed separately from the nuclear reactor and monitors the reactor in the event of a reactor abnormality. A method for confirming the integrity of a reactor measurement system, which is installed inside a reactor storage container and operates when the reactor is abnormal to confirm the integrity of a plurality of sensors that transmit measurement signals to the control unit. The step in which the control unit receives the measurement signals of the plurality of sensors and the control unit compare the stored analysis data for each event pattern with the measurement signals to calculate the correlation, and the correlation with the measurement signals is calculated. A step of extracting high analysis data, a step of estimating an event pattern corresponding to the extracted analysis data as an event occurring in the reactor, and a measurement signal of the plurality of sensors in the estimated event pattern. It is provided with a step of obtaining an estimated value of the above, and a step of comparing the measurement signals of the plurality of sensors with the estimated value and determining the presence or absence of an abnormality in the plurality of sensors.

According to the embodiment of the present invention, it is possible to confirm the soundness of the sensor installed in the reactor containment vessel used for monitoring the nuclear power plant in the event of an accident.

The block diagram of the nuclear reactor measurement system which concerns on 1st Embodiment of this invention. The flowchart of the process performed in the nuclear reactor measurement system which concerns on 1st Embodiment of this invention. The block diagram of the nuclear reactor measurement system which concerns on 2nd Embodiment of this invention.

Hereinafter, examples of the present invention will be described with reference to the drawings.

(Example 1)
This embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing an outline of a nuclear reactor measurement system according to the present embodiment.

(Constitution)
The nuclear power plant 51 and the emergency control facility 52 installed for controlling the nuclear power plant 51 in the event of an accident are installed at a distance (for example, 100 m or more). The nuclear power plant 51 includes a reactor containment vessel 53, and a plurality of sensors installed in the reactor containment vessel 53 are connected to the control unit 12 of the emergency control facility 52 via a long-distance transmission line, resulting in an accident. At the time of occurrence, the reactor containment vessel 53 is monitored at the emergency control facility 52. The emergency control facility 52, a plurality of sensors, and the like are installed as, for example, equipment for dealing with a specific serious accident.

In addition to the reactor containment vessel 53, the nuclear power plant 51 includes a reactor building containing the reactor containment vessel 53, a reactor pressure vessel contained in the reactor containment vessel 53, a central control room, and the like (illustrated). abridgement).

In FIG. 1, direct measurement type gas detectors 1a, 1b, 1c, and 1d connected to the emergency control facility 52 are installed in the reactor containment vessel 53. For multiplexing, a plurality of gas detectors (two in the present embodiment) are provided for the same measurement target, and the gas detectors 1a and 1b, 1c and 1d are paired with each other. Further, the radiation detectors 2a, 2b, 2c and 2d connected to the emergency control facility 52 are installed in the reactor containment vessel penetration 23. Since the radiation detectors are multiplexed, a plurality of radiation detectors (two in the present embodiment) are provided for the same measurement target, and the radiation detectors 2a and 2b, 2c and 2d are paired. Further, a thermometer 5 and a pressure gauge 6 connected to the emergency control facility 52 are provided, and the signal of the detector is output to the control unit 12 of the emergency control facility 52. Hereinafter, all of the gas detectors 1a, 1b, 1c, 1d, the radiation detectors 2a, 2b, 2c, 2d, the thermometer 5, and the pressure gauge 6 may be collectively referred to as various sensors.

The gas detectors 1a, 1b, 1c, 1d, and the radiation detectors 2a, 2b, 2c, and 2d are installed as equipment that is required to operate only in the event of an accident at the nuclear plant 51, and the power supply is also a power supply system dedicated to the accident. It is supplied from 14. However, in order to confirm the soundness described later, the nuclear power plant 51 is operated during normal operation at any time, either periodically or by operation. Therefore, the power supply 15 for operating during normal operation is also supplied.

The control unit 12 includes calculation means, signal processing means, display means, etc., converts measurement signals of various sensors into measurement signal values such as gas concentration and radiation dose rate, presents them to the operator, issues an alarm, and the like. It is an electronic device having a function necessary for monitoring the nuclear plant 51 in the event of an accident. The presentation to the operator and the alarm are performed by the display unit (alarm unit) 13 connected to the control unit 12. For the sake of brief explanation, the measured signal value obtained by converting the measured signal is also described below as the measured signal.

The control unit 12 particularly includes a determination means 31 and a database 32. The determination means 31 determines the soundness of various sensors based on the measurement signals received from the various sensors and the data read from the database 32, and is implemented as a function executed by the calculation means of the control unit 12. To.

The database 32 stores parameters measured by sensors installed in the reactor containment vessel 53 as analysis data for each of a plurality of event patterns assumed at the time of an accident at the nuclear plant 51. More specifically, the behavior of measured parameters such as dose rate, gas concentration, temperature, and pressure due to time changes from the time of the accident, and the correlation between different parameters are recorded for each event pattern. There is. This analysis data is created by, for example, analysis using parameters measured during normal operation and accident of a nuclear plant and conditions of an assumed accident event. Here, the event pattern includes, for example, the content of an accident occurring in the nuclear plant 51, the operating mode of the reactor at the time of the event occurrence, the soundness of the reactor pressure vessel and the cooling system, water injection, decompression, gas concentration control, and the like. It is classified according to the operating status of equipment related to safety functions.

Further, the determination means 31 has a configuration in which the estimated values of the radiation detector and the gas detector based on the analysis data for each event pattern can be compared in the control unit 12 of the emergency control room. The estimated value referred to here is a value that can be taken by each of the measurement signals of various sensors in a certain event.

(Action)
The operation of this embodiment will be described below with reference to FIG. FIG. 2 is a flowchart of processing executed by the determination means 31.

In the configuration of the present embodiment, measurement signals from various sensors are transmitted to the control unit 12 of the emergency control facility 52 and accepted by the determination means 31 (step S1). Here, in the control unit 12, the determination means 31 compares the behavior of the actual signals of various sensors with the passage of time and the behavior of the estimated value. For parameters such as dose rate, gas concentration, temperature, and pressure, the behavior of the actual signal and the behavior of the analysis data for each event pattern are sequentially compared to calculate the correlation, and the analysis data with high correlation with the behavior of the actual measured value is obtained. Extract (step S2). Then, the event pattern corresponding to the extracted analysis data is estimated as an assumed event occurring in the reactor containment vessel 53 (step S3 Yes, step S4).

Here, if the actual measured values of parameters such as dose rate, gas concentration, temperature, and pressure have low correlation with the analysis data in any event pattern, an alarm is given using the display unit (alarm unit) 13 of the emergency control room. Is issued (step S3 No, step S5). In other words, as a result of the calculation, if all of the event patterns do not satisfy the conditions (high correlation) that are determined to be assumed events, is an unexpected event that does not correspond to the event pattern recorded in the database occurring? , An alarm is issued on the assumption that an abnormality may have occurred in a plurality of sensors (step S5).

When an event pattern to be an assumed event is extracted, the estimated value of various sensors in the event pattern of the assumed event (that is, the range of values that can be taken by each measurement signal of each sensor) is obtained (step S6). Specifically, the estimated value in the event pattern is also stored in the database 32 and read from the database 32, or the conditional expression or the conditional processing step is performed so that the determination means 31 can calculate based on the condition in the event pattern. In combination, the determination means 31 may calculate.

The determination means 31 compares whether or not the measurement signal, which is an actual signal received from various sensors, matches the estimated value (step S7). Here, since the estimated value is a range of possible values for each of the measurement signals of the various sensors, more specifically, it is determined whether or not the measurement signal is included in the range of the estimated value. Then, among various sensors, those whose measurement signal is not included in the estimated value are extracted. When the measurement signals and the estimated values match for all of the various sensors, the process ends (step S8 No).

When a sensor whose estimated value does not match the measured signal is extracted, it is determined that an abnormality has occurred in the extracted sensor, an alarm is issued, and the process ends (step S8 Yes, step S9).

On the other hand, in step S3, a plurality of event patterns may be extracted as assumed events. For example, it is conceivable to set to extract a specified number in descending order of correlation, or to extract all event patterns having a correlation of a predetermined value or higher. In this case, the processes of steps S6, S7, and S8 are executed sequentially or in parallel for the extracted plurality of event patterns.

For example, when the measured values of the above parameters are compared with the database of the analysis results of each event pattern and the results match the specific event pattern at the time of the accident except for one parameter, the specific event at the time of the accident There is a possibility that the detector of the measured value that does not match the pattern has failed. In this case, compare whether the behavior of each parameter matches the behavior in other event patterns, and if it does not match any event pattern, an abnormality has occurred in the detector of the parameter that does not show the above fluctuation. Judge. On the other hand, when the measurement signals of the various sensors and the estimated values match in other event patterns, the event pattern is regarded as the final assumed event, and it is determined that there is no abnormality in the various sensors.

Here, a plurality of event patterns may be displayed on the display unit (alarm unit) 13 as possible assumed events. In addition, there is a possibility that the assumed event cannot be immediately identified as one due to the event pattern or the output of the signal due to the abnormality of various sensors. In this case, a plurality of assumed events and the determination results of the soundness of various sensors for each event pattern may be presented to the operator.

Further, in step S2, when the measurement signals of the paired sensors among the measurement signals received from the various sensors deviate from each other, the paired sensors may be individually adopted in the correlation calculation to perform the calculation. .. For example, when the measurement signals of the gas detectors 1a and 1b are divergent, the correlation calculation based on the measurement signals of various sensors excluding the gas detector 1a and the measurement signals of various sensors excluding the gas detector 1b Correlation calculation based on is performed individually, and the event pattern is extracted for each. If the measurement signals of the paired sensors are divergent, there is a high possibility that an abnormality has occurred in at least one of them. Therefore, as a result of trying to extract the event pattern individually as described above, for example, the former has an event pattern. If the latter is extracted and the event pattern is not extracted, it can be determined that there is a high possibility that an abnormality has occurred in the gas detector 1a. Of course, there are cases where both the gas detectors 1a and 1b have an abnormality, so it is desirable to continue performing the subsequent processing to make a judgment.

(effect)
According to this embodiment, the radiation detector or gas detector utilizes the fact that the dose rate, specific gas concentration, temperature, pressure, etc. may change in a correlated manner depending on the state of the nuclear reactor at the time of an accident. When an incorrect value is indicated for some reason, the soundness of various sensors can be determined. By showing the possibility that various sensors are not sound to the emergency control facility, it is possible to confirm the soundness of the detector when the detector is operated during plant operation and when an accident occurs.

(Example 2)
This embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing an outline of the reactor measurement system according to the present embodiment. The same components as those in the first embodiment are designated by the same reference numerals, and redundant description will be omitted.

(Constitution)
The reactor measurement system of this embodiment includes the existing sensors shown below. Moreover, the electronic device (central control room electronic device) of the central control room which receives the measurement signal of these existing sensors is illustrated.

As an existing direct measurement type gas detector, a gas detector 3a, 3b, 3c, 3d that directly measures the gas concentration in the reactor containment vessel, and as an existing sampling type gas detector, the reactor is stored by a sampling pump 22. There are sampling type gas detectors 7a and 7b that sample the gas in the container and measure the gas concentration outside the reactor containment vessel. All of these existing detectors are connected to the central control room electronic device 11. Here, the existing direct measurement type gas detector has a configuration in which 3a and 3b, 3c and 3d are paired, and the sampling type gas detector has a configuration in which 7a and 7b are paired, respectively. The sampling type gas detectors 7a and 7b have a configuration in which the measurement target can be switched by the switching valve 21, and the calibration reference gas is flowed from the calibration gas cylinder 24 to the sampling pipe by the switching valve 21 to periodically during plant operation. It is possible to calibrate. Further, the existing radiation detectors 4a, 4b, 4c, and 4d are installed and connected to the central control room electronic device 11. The radiation detectors 4a and 4b are paired, and the radiation detectors 4c and 4d are paired. The central control room electronic device 11 can transmit and record the detector signal transmitted to the central control room electronic device 11 to the control unit 12 of the emergency control facility 52 via the transmission line 41. It has become. The number of detectors is not limited to the above number.

(Action)
In the above configuration, the existing direct measurement type gas detectors 3a, 3b, 3c and 3d and the sampling type gas detectors 7a and 7b are always in operation during the normal operation of the plant. The measured value of the detector is recorded by the control unit 12 of the emergency control facility via the electronic device 11 in the central control room. As shown in FIG. 3, the measurement target is the same for the detector provided as the equipment for dealing with a specific serious accident and the existing detector.

Here, the gas detectors 1a, 1b, 1c, and 1d are operated periodically during plant operation and at arbitrary timings operated by an operator or the like. The periodic operation referred to here is an operation in plant monitoring such as once an hour, once a day, once a week (gas detectors 3a, 3b, 3c, 3d during normal operation of the plant). , Radiation detectors 4a, 4b, 4c, 4d, and gas detectors 1a, 1b, 1c, 1d, radiation detectors 2a, 2b, 2c, 2d in an emergency) It is a short operation. The control unit 12 compares the measured values with the measured values of the existing direct measurement type gas detectors 3a, 3b, 3c and 3d having the same measurement target and the measured values of the sampling type gas detectors 7a and 7b. Measure the same measurement target with any of the gas detectors 3a, 3b, 3c, 3d, and the switching valve 21, which have the same measurement target as any of the measurement values of the gas detectors 1a, 1b, 1c, and 1d. When there is a significant (for example, exceeding a preset threshold value) difference with respect to the measured value of any of the sampling type gas detectors 7a and 7b in the state of being in the control unit 12, the control unit 12 is displayed (alarm unit) 13 To issue an alarm using.

Similarly, the radiation detectors 2a, 2b, 2c, and 2d are also operated periodically during plant operation or at an arbitrary timing by an operator's operation, and the measured values are measured as existing radiation detections having the same measurement target. When there is a significant difference from any of the measured values of the devices 4a, 4b, 4c, and 4d, an alarm is issued from the display unit (alarm unit) 13.

(effect)
According to this embodiment, for the gas detectors 1a, 1b, 1c and 1d, the existing gas detectors 3a, 3b, 3c and 3d that operate during the normal operation of the plant and the sampling type gas detection that is periodically calibrated. The soundness can be confirmed by using the measured values of the instruments 7a and 7b. Further, the soundness of the radiation detectors 2a, 2b, 2c and 2d can be confirmed by using the existing radiation detectors 4a, 4b, 4c and 4d that operate during the normal operation of the plant. Therefore, it is possible to easily confirm the soundness of the detector for emergency control facilities that is not always operated at regular or arbitrary timings.

In each of the above-described embodiments, the equipment for dealing with a specific serious accident or the like is mainly assumed, and the description is made based on the required functions, but the present invention is not limited to these. For example, it is possible to connect various sensors other than those listed in each embodiment to the emergency control facility 52 and use them as soundness determination targets.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

For example, a database 32 can be provided in the second embodiment, soundness can be confirmed by the second embodiment during normal operation, and monitoring and alarm issuance can be performed using the database 32 in an emergency. With such a configuration, if a sensor abnormality occurs during normal operation of the plant, the sensor can be excluded before analysis, and an accident occurs where it was sound during normal operation of the plant. Since it is possible to determine the abnormality by analysis for the sensor in which the abnormality occurs due to the above, the system can be made more reliable.

The control unit 12 described above includes a control device in which processors such as a dedicated chip, FPGA (Field Programmable Gate Array), GPU (Graphics Processing Unit), or CPU (Central Processing Unit) are highly integrated, and a ROM (Read). Storage devices such as Only Memory) and RAM (Random Access Memory), external storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive), display devices such as displays, and input devices such as mice and keyboards. And a communication I / F, which can be realized by a hardware configuration using a normal computer.

51 ... Nuclear plant, 52 ... Emergency control facility, 53 ... Reactor containment vessel, 1a, 1b, 1c, 1d, 3a, 3b, 3c, d ... Gas detector, 2a, 2b, 2c, 2d, 4a, 4b , 4c, 4d ... Radiation detector, 5 ... Thermometer, 6 ... Pressure gauge, 7a, 7b ... Sampling type gas detector, 11 ... Central control room electronic device, 12 ... Control unit, 13 ... Display unit (alarm unit) , 14 ... power supply system, 15 ... power supply, 21 ... switching valve, 22 ... sampling pump, 23 ... penetration, 24 ... calibration gas cylinder, 31 ... judgment means, 32 ... database

Claims (7)

A control unit installed separately from the nuclear power plant and provided in the emergency control room that monitors the reactor in the event of a reactor abnormality.
A plurality of first sensors installed inside the reactor containment vessel and transmitting measurement signals to the control unit, and
With
The control unit
A database accumulating analysis data that analyzes the behavior of the nuclear power plant during operation and accidents for each event pattern that can occur in the nuclear power plant.
A determination unit that determines the soundness of the plurality of first sensors based on the measurement signals received from the plurality of first sensors and the analysis data.
Reactor measurement system equipped with. The reactor measurement system according to claim 1, wherein the analysis data includes a correlation between parameters measured by the first sensor, which is obtained by analyzing the behavior of a nuclear power plant during normal operation and during an accident. The determination unit compares the measurement signal with the analysis data of each of the event patterns, estimates the assumed event in the nuclear plant, and estimates the assumed event.
The measurement signal estimated value, which is a value that the measurement signal can take in the assumed event, is obtained.
The measurement signal is compared with the measurement signal estimated value, and it is determined that there is an abnormality in the first sensor that outputs the measurement signal estimated value that does not match the measurement signal estimated value among the plurality of first sensors. The reactor measurement system according to claim 1 or 2. The parameters to be measured, which are installed inside the reactor containment vessel, are the same as those of the first sensor, and are always operated during the normal operation of the reactor, and the central control room control provided in the central control room of the nuclear power plant. The second sensor that sends the measurement signal to the unit and
A transmission means for transmitting the measurement signal of the second sensor received by the central control room control unit to the emergency control room control unit is provided.
The first sensor operates intermittently during the normal operation of the reactor,
The control unit has a second determination unit for determining whether the difference between the measurement signal of the first sensor and the measurement signal of the second sensor received during the normal operation of the nuclear power plant is within an allowable range. Item 3. The reactor measurement system according to any one of Items 1 to 3. An emergency control room control unit installed in an emergency control room that is installed away from the nuclear power plant and monitors the reactor in the event of a reactor abnormality.
A central control room control unit provided in the central control room of the nuclear power plant,
A first sensor that is installed inside the reactor containment vessel, operates intermittently during normal operation of the reactor, and transmits a measurement signal to the emergency control room control unit.
A second sensor installed inside the reactor containment vessel, having the same measurement parameters as the first sensor, always operating during normal operation of the reactor, and transmitting a measurement signal to the central control room control unit. ,
A transmission means for transmitting the measurement signal of the second sensor received by the central control room control unit to the emergency control room control unit is provided.
The control unit is a nuclear reactor measurement system having a determination unit for determining whether or not the difference between the received measurement signal of the first sensor and the measurement signal of the second sensor is within an allowable range. A sampling means for sampling the gas in the reactor containment vessel, a calibration gas supply means for supplying the calibration gas, the gas sampled by the sampling means, and the calibration gas are measured and the measurement signal is transmitted to the central control room. Further equipped with a sampling type gas sensor having a gas sensor for transmitting to the control unit,
The first sensor includes an accident gas sensor having the same parameters as the sampling type gas sensor to be measured.
The determination unit compares the measurement signal of the sampling type gas sensor received from the control room control unit with the measurement signal of the gas sensor for an accident to determine the soundness of the gas sensor for an accident. Item 5. The reactor measurement system according to item 5. It is installed away from the nuclear power plant, connected to the control unit provided in the emergency control room that monitors the reactor in the event of a reactor abnormality, installed inside the reactor containment vessel, and operates in the event of a reactor abnormality. This is a method for confirming the soundness of a nuclear reactor measurement system, which confirms the soundness of a plurality of sensors that transmit measurement signals to the control unit.
A step in which the control unit receives the measurement signals of the plurality of sensors,
A step in which the control unit compares the stored analysis data for each event pattern with the measurement signal, calculates a correlation, and extracts analysis data having a high correlation with the measurement signal.
A step of estimating the event pattern corresponding to the extracted analysis data as an event occurring in the reactor, and
In the step of obtaining the estimated value of the measurement signals of the plurality of sensors in the estimated event pattern,
A method for confirming the soundness of a nuclear reactor measurement system, comprising a step of comparing measurement signals of the plurality of sensors with the estimated values and determining the presence or absence of abnormalities in the plurality of sensors.

Images