CN112907914A - Nuclear criticality alarm system and alarm method thereof - Google Patents
Nuclear criticality alarm system and alarm method thereof Download PDFInfo
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- CN112907914A CN112907914A CN202110180639.2A CN202110180639A CN112907914A CN 112907914 A CN112907914 A CN 112907914A CN 202110180639 A CN202110180639 A CN 202110180639A CN 112907914 A CN112907914 A CN 112907914A
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/18—Status alarms
- G08B21/182—Level alarms, e.g. alarms responsive to variables exceeding a threshold
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
- G08B29/18—Prevention or correction of operating errors
- G08B29/185—Signal analysis techniques for reducing or preventing false alarms or for enhancing the reliability of the system
- G08B29/188—Data fusion; cooperative systems, e.g. voting among different detectors
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B7/00—Signalling systems according to more than one of groups G08B3/00 - G08B6/00; Personal calling systems according to more than one of groups G08B3/00 - G08B6/00
- G08B7/06—Signalling systems according to more than one of groups G08B3/00 - G08B6/00; Personal calling systems according to more than one of groups G08B3/00 - G08B6/00 using electric transmission, e.g. involving audible and visible signalling through the use of sound and light sources
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Abstract
The invention discloses a nuclear critical alarm system and an alarm method thereof, wherein the system comprises a radiation monitoring host, a plurality of composite detectors and an alarm whistle, the radiation monitoring host comprises a detector signal acquisition and processing unit, a nuclear critical alarm logic unit, a display processing unit, a power supply unit and an interface unit, the composite detectors are connected with the input ends of the detector signal acquisition and processing unit and the nuclear critical alarm logic unit, and the alarm whistle is connected with the output end of the nuclear critical alarm logic unit; the composite detector comprises a signal processing module, a first GM detector, a second GM detector, a plastic flash detector, a source detection LED, a first high-voltage module and a second high-voltage module. The system has the advantages of simple structure, reasonable design, convenient realization, wide detection range, extremely high response speed, good use effect and convenient popularization and use, can be effectively applied to gamma nuclear critical monitoring, and can improve the stability and reliability of a nuclear critical alarm system by combining an alarm method.
Description
Technical Field
The invention belongs to the technical field of nuclear radiation detection, and particularly relates to a nuclear critical alarm system and an alarm method thereof.
Background
The nuclear critical alarm system can monitor the gamma ray or neutron radiation dose of nuclear fuel production, processing, storage, and post-processing plants or experimental research stacks to reflect radiation transients in these locations and prevent fuel component damage or radioactive emissions due to critical events from fuel stacking. When critical accidents happen in the places, the system can accurately and timely give out sound and light alarms to prompt people to evacuate and take emergency measures.
According to different use places and monitoring principles, the nuclear critical alarm system is divided into two types: a nuclear gamma critical alarm instrument and a neutron critical alarm instrument. The nuclear critical alarm system generally has more than three detection channels which are arranged at different measuring points and are mutually redundant, each channel is provided with the same alarm threshold value, and in order to reduce false alarms and improve the alarm reliability of the system, an instrument can externally give an alarm when at least two channels detect a critical accident.
Since the nuclear critical events are extremely short in duration (milliseconds) and generate extremely large radiation fields, various factors combine to cause common area radiation detectors to fail. Therefore, the nuclear critical alarm system must consider the response time of the detector, the measurement range and other limit conditions. Meanwhile, as an integral system, the stability and reliability of a critical alarm system are also important, any missed alarm or delayed alarm can cause unforeseen safety accidents, and any false alarm can cause serious economic loss and personnel panic.
Thus, a nuclear-critical alarm system should detect the smallest nuclear-critical event as quickly as possible and trigger an alarm with the least delay. At present, the minimum nuclear critical event is defined as the equivalent absorbed dose of 0.2Gy generated in free air at a distance of 2m from the reaction material within 60 s. The minimum time for the radiation transient to last is 1ms (Full Width Half Maximum), and the nuclear critical alarm system should detect the radiation transient within 1ms and confirm the alarm.
In the prior art, a detector of a BH3208 nuclear critical alarm and measurement system of a medium nuclear control system engineering limited company adopts 3 GM tubes, the measurement range of the GM tubes is 0.1 mu Gy/h-25 Gy/h, 1ms radiation transient cannot be identified theoretically, and the measurement requirement of critical accident alarm cannot be met. Moreover, the product has inherent defects in a physical method, 3 detectors are GM tubes, when a critical accident occurs, the GM tubes are saturated due to the instantaneous increase of the measured dose, and the pulse signal output of the GM tubes is greatly reduced at this time, so that the function of critical alarm cannot be met.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a nuclear critical alarm system, which has the advantages of simple structure, reasonable design, convenient implementation, wide detection range, fast response speed, good use effect and convenient popularization and use, and can be effectively applied to nuclear critical monitoring.
In order to solve the technical problems, the invention adopts the technical scheme that: a nuclear critical alarm system comprises a radiation monitoring host, a plurality of composite detectors connected with the radiation monitoring host, and an alarm whistle connected with the output end of the radiation monitoring host; the radiation monitoring host comprises a detector signal acquisition and processing unit, a nuclear critical alarm logic unit, a display processing unit and a power supply unit for supplying power to all power utilization units in the radiation monitoring host, the detector signal acquisition and processing unit, the nuclear critical alarm logic unit, the display processing unit and the power supply unit are all connected with one another through interface units, the composite detector is connected with the detector signal acquisition and processing unit and the input end of the nuclear critical alarm logic unit through the interface units, and the alarm whistle is connected with the output end of the nuclear critical alarm logic unit through the interface units;
the compound detector includes signal processing module, first GM detector, second GM detector, moulds and dodges the detector and the source examines the LED, first GM detector, second GM detector and mould and dodge the detector and all be connected with signal processing module's input, signal processing module's output termination has first high pressure module and second high pressure module, first GM detector and second GM detector all are connected with first high pressure module's output, it is connected with the output of second high pressure module to mould to dodge the detector, the source is examined the LED and is connected with signal processing module's output, signal processing module meets with detector signal acquisition processing unit, it is connected with the input of nuclear critical warning logical unit to mould to dodge the detector.
In the nuclear critical alarm system, the input end of the radiation monitoring host is connected with the manual alarm removing unit arranged outside the withdrawing area.
In the nuclear critical alarm system, the number of the composite detectors is at least three.
The nuclear critical alarm system comprises a signal gating circuit and a two-out-of-three alarm logic circuit, wherein the signal gating circuit comprises a logic buffer U21, a logic buffer U22, a logic buffer U23, a resistor R112, a resistor R113 and a resistor R114, an enable signal input terminal STATE _1 of the logic buffer U21, an alarm signal input terminal EVENT1_ WD of the logic buffer U21, an enable signal input terminal STATE _2 of the logic buffer U22, an alarm signal input terminal EVENT2_ WD of the logic buffer U22, an enable signal input terminal STATE _3 of the logic buffer U23 and an alarm signal input terminal EVENT3_ WD of the logic buffer U23 are all connected with a signal processing module through an interface unit, an alarm signal output terminal N _ EVENT _1 of the logic buffer U21 is grounded through the resistor R112, an alarm signal output terminal N _ EVENT _2 of the logic buffer U22 is grounded through the resistor EVR 113, the alarm signal output end N _ EVENT _3 of the logic buffer U23 is grounded through a resistor R114; the two-out-of-three alarm logic circuit comprises a NAND gate NAND1, a NAND gate NAND2, a NAND gate NAND3 AND an AND gate AND1, two input ends of the NAND gate 1 are respectively connected with the alarm signal output end N _ EVENT _1 of the logic buffer U21 and the alarm signal output end N _ EVENT _2 of the logic buffer U22, two input ends of the NAND gate 2 are respectively connected with the alarm signal output end N _ EVENT _2 of the logic buffer U22 and the alarm signal output end N _ EVENT _3 of the logic buffer U23, two input ends of the NAND gate 3 are respectively connected with the alarm signal output end N _ EVENT _1 of the logic buffer U21 and the alarm signal output end N _ EVENT _3 of the logic buffer U23, the output end of the NAND gate 1, the output end of the NAND gate 2 AND the output end of the NAND gate 3 are respectively connected with three input ends of an AND gate 1, the output end of the AND gate AND1 is the alarm signal output end BJR of the two-out-of-three alarm logic circuit.
In the nuclear critical alarm system, the detection range of the first GM detector is 0.1 mu Gy/h-0.5 mGy/h, the detection range of the second GM detector is 0.5 mGy/h-3 Gy/h, and the detection range of the plastic flash detector is 0.05 Gy/h-25 Gy/h.
The plastic flash detector comprises a plastic scintillator and a photomultiplier arranged on the side face of the plastic scintillator, and the source detection LED is arranged on a photomultiplier tube seat.
The invention also discloses an alarm method of the nuclear critical alarm system, which comprises a critical accident monitoring alarm method and a checking method of the nuclear critical alarm system in the operation and maintenance process.
The alarm method of the nuclear critical alarm system comprises the following specific steps:
step one, monitoring the gamma radiation dose rate at the installation position in real time by the first GM detector and the second GM detector, and monitoring the critical accident at the installation position in real time by the plastic flash detector;
step two, the signal processing module transmits the monitoring acquisition data of the first GM detector and the second GM detector to a display processing unit of the radiation monitoring host through an RS485 interface; the signal processing module monitors the running state of the detector in real time and outputs a failure fault signal to the nuclear critical alarm logic unit;
thirdly, the display processing unit processes signals of the first GM detector and the second GM detector, and outputs an alarm signal to the nuclear critical alarm logic unit when the signals are larger than an alarm threshold value;
step four, in the process of the step two to the step three, the electric signal output by the plastic flash detector is divided into two paths after integral forming, one path is subjected to threshold value identification, the output signal is sent to a nuclear critical alarm logic unit to be subjected to redundancy coincidence logic processing, and whether a critical accident occurs is judged; the other path of the pulse signals is transmitted to a detector signal acquisition and processing unit in the radiation monitoring host machine after differential conversion for pulse signal acquisition and recording;
the nuclear critical alarm logic unit performs signal gating and two-out-of-three alarm discrimination through a hardware logic circuit, when the nuclear critical alarm logic unit receives that the current channel detector running state signal is normal, the channel alarm signal can enter a two-out-of-three alarm logic circuit, and when the current channel detector running state signal is failure fault, the channel alarm signal cannot enter the two-out-of-three alarm logic circuit; when at least two paths of the three paths of signals received by the nuclear critical alarm logic unit are alarm signals at the same time, outputting a critical alarm signal;
sixthly, when at least two composite detectors in the plurality of composite detectors trigger alarm at the same time, the alarm whistle works; when part of the composite detectors fails and the rest two composite detectors work normally, the two composite detectors trigger an alarm and the alarm whistle works; when part of the composite detectors fails and the rest composite detectors work normally, the alarm can not be judged by one composite detector signal and the alarm whistle does not work.
The alarm method of the nuclear critical alarm system comprises the following specific steps of: the inspection signals are triggered manually and transmitted to the signal processing module of each composite detector through the radiation monitoring host, the signal processing module excites the source to detect the LED simulation plastic flash radiation fluorescent signals, critical accident occurrence is simulated, and the composite detectors detect the signals simultaneously to give an alarm, so that the nuclear critical alarm system is inspected.
In the alarm method of the nuclear critical alarm system, the detector signal acquisition and processing unit in the radiation monitoring host adopts multi-channel parallel acquisition, simultaneously acquires and displays pulse waveforms of a plurality of composite detectors, records the measured pulse waveforms within the critical accident duration, and is used for post-accident investigation to confirm the radiation intensity, the occurrence time and the duration of the critical accident.
Compared with the prior art, the invention has the following advantages:
1. the system of the invention has simple structure, reasonable design and convenient realization.
2. The composite detector of the invention is designed by combining the first GM detector, the second GM detector and the plastic flash detector, the first GM detector and the second GM detector are combined for measurement, the measurement range is wide, low-intensity radiation measurement is carried out, the plastic flash detector adopts a current integration mode for radiation measurement, the rising time, the pulse width and the pulse amplitude of an integrated pulse contain the time, the duration and the accumulated radiation intensity information of the occurrence of a critical accident, the saturation resistance is strong, the upper limit of measurement is high, the response speed is fast, the advantage complementation is realized, and the overall detection efficiency and the accuracy of the composite detector are improved.
3. The radiation monitoring host of the invention carries out parallel processing on radiation intensity measurement and alarm logic, the detector signal acquisition and processing unit adopts multi-channel parallel acquisition, simultaneously acquires and displays pulse waveforms of a plurality of composite detectors, records the measurement pulse waveforms within the duration time of a critical accident, and is used for post-accident investigation to confirm the radiation intensity, the occurrence time and the duration time of the critical accident; the nuclear critical alarm logic unit adopts a hardware logic circuit to carry out alarm judgment, the output alarm response is fast, and the false alarm probability is greatly reduced through the 3-out-of-2 redundancy coincidence judgment.
4. According to the invention, the source detection LED is arranged in the composite detector, the plastic flash radiation fluorescent signal is simulated, the composite detectors use the same excitation signal, the excitation signal parameter is adjustable, the information such as the state of each unit in the nuclear critical alarm system, the function of a full signal chain, the response time and the like can be checked, and the simulation training and the system check are convenient for a user.
5. The method can be effectively applied to gamma nuclear critical monitoring, has wide detection range and high response speed, can improve the stability and reliability of a nuclear critical alarm system by combining an alarm method, has good use effect and is convenient to popularize and use.
In conclusion, the system disclosed by the invention is simple in structure, reasonable in design, convenient to implement, wide in detection range, high in response speed, good in use effect and convenient to popularize and use, can be effectively applied to gamma nuclear critical monitoring, and can improve the stability and reliability of a nuclear critical alarm system by combining an alarm method.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a schematic block diagram of the system of the present invention;
FIG. 2 is a schematic diagram of a signal gating circuit in the nuclear critical alarm logic unit of the present invention;
FIG. 3 is a schematic diagram of a two-out-of-three alarm logic circuit in the nuclear critical alarm logic unit of the present invention.
Description of reference numerals:
1-radiation monitoring host computer; 1-a detector signal acquisition processing unit;
1-2-nuclear critical alarm logic unit; 1-3-a display processing unit; 1-5-a power supply unit;
1-6-interface unit; 2-a composite detector; 2-1-a signal processing module;
2-2 — first GM probe; 2-3 — second GM probe; 2-4-plastic flash detector;
2-5-source detection LED; 2-6 — a first high voltage module; 2-7-a second high voltage module;
3, alarm whistle; 4-alarm manual release unit.
Detailed Description
As shown in fig. 1, the nuclear critical alarm system of the present invention includes a radiation monitoring host 1, a plurality of composite detectors 2 connected to the radiation monitoring host 1, and an alarm whistle 3 connected to an output end of the radiation monitoring host 1; the radiation monitoring host 1 comprises a detector signal acquisition processing unit 1-1, a nuclear critical alarm logic unit 1-2 and a display processing unit 1-3, and a power supply unit 1-5 for supplying power to each power consumption unit in the radiation monitoring host, wherein the detector signal acquisition processing unit 1-1, the nuclear critical alarm logic unit 1-2, the display processing unit 1-3 and the power supply unit 1-5 are all connected with each other through an interface unit 1-6, the composite detector 2 is connected with the input ends of the detector signal acquisition processing unit 1-1 and the nuclear critical alarm logic unit 1-2 through the interface units 1-6, the alarm whistle 3 is connected with the output end of the nuclear critical alarm logic unit 1-2 through the interface unit 1-6; the compound detector 2 comprises a signal processing module 2-1, a first GM detector 2-2, a second GM detector 2-3, a plastic flash detector 2-4 and a source detection LED2-5, wherein the first GM detector 2-2, the second GM detector 2-3 and the plastic flash detector 2-4 are all connected with the input end of the signal processing module 2-1, the output end of the signal processing module 2-1 is connected with a first high-voltage module 2-6 and a second high-voltage module 2-7, the first GM detector 2-2 and the second GM detector 2-3 are all connected with the output end of the first high-voltage module 2-6, the plastic flash detector 2-4 is connected with the output end of the second high-voltage module 2-7, the source detection LED2-5 is connected with the output end of the signal processing module 2-1, the signal processing module 2-1 is connected with the detector signal acquisition processing unit 1-1, and the plastic flash detector 2-4 is connected with the input end of the nuclear critical alarm logic unit 1-2.
During specific implementation, the radiation monitoring host 1 is used for acquiring, processing, storing, displaying and alarming detection data, the composite detector 2 is used for monitoring radiation transient and gamma dose rate at the position in real time, converting the monitoring data into switching value signals and digital signals and outputting the switching value signals and the digital signals to the radiation monitoring host 1.
In this embodiment, the input end of the radiation monitoring host 1 is connected with an alarm manual release unit 4 arranged outside the removal area.
In specific implementation, once the alarm signal is triggered, the alarm signal needs to be reset manually, and a reset button or a switch in the manual alarm release unit 4 is arranged outside the evacuation area; remote manual reset can also be performed by software control, where a manual reset button or switch responds to the priority.
In this embodiment, the number of the composite detectors 2 is at least three.
In specific implementation, in order to ensure redundancy in design and reduce false alarm, the nuclear critical alarm system detector is composed of at least three groups of same composite detectors 2, and the number of the composite detectors 2 can be configured according to the number of monitoring points.
In this embodiment, the nuclear-critical alarm logic unit 1-2 includes a signal gating circuit and a two-out-of-three alarm logic circuit, as shown in fig. 2, the signal gating circuit includes a logic buffer U21, a logic buffer U22, a logic buffer U23, a resistor R112, a resistor R113, and a resistor R114, the enable signal input STATE _1 of the logic buffer U21, the alarm signal input EVENT1_ WD of the logic buffer U21, the enable signal input STATE _2 of the logic buffer U22, the alarm signal input EVENT2_ WD of the logic buffer U22, the enable signal input STATE _3 of the logic buffer U23, and the alarm signal input EVENT3_ WD of the logic buffer U23 are all connected to the signal processing module (2-1) through the interface units (1-6), the alarm signal output N _ EVENT _1 of the logic buffer U21 is grounded through the resistor R112, the alarm signal output end N _ EVENT _2 of the logic buffer U22 is grounded through a resistor R113, and the alarm signal output end N _ EVENT _3 of the logic buffer U23 is grounded through a resistor R114; as shown in fig. 3, the two-out-of-three alarm logic circuit includes NAND gate NAND1, NAND gate NAND2, NAND gate NAND3 AND gate AND1, two input ends of the NAND gate 1 are respectively connected with the alarm signal output end N _ EVENT _1 of the logic buffer U21 and the alarm signal output end N _ EVENT _2 of the logic buffer U22, two input ends of the NAND gate 2 are respectively connected with the alarm signal output end N _ EVENT _2 of the logic buffer U22 and the alarm signal output end N _ EVENT _3 of the logic buffer U23, two input ends of the NAND gate 3 are respectively connected with the alarm signal output end N _ EVENT _1 of the logic buffer U21 and the alarm signal output end N _ EVENT _3 of the logic buffer U23, the output end of the NAND gate 1, the output end of the NAND gate 2 AND the output end of the NAND gate 3 are respectively connected with three input ends of an AND gate 1, the output end of the AND gate AND1 is the alarm signal output end BJR of the two-out-of-three alarm logic circuit.
In specific implementation, the nuclear critical alarm logic unit 1-2 adopts a hardware logic circuit to carry out signal gating and alarm judgment, the output alarm response is fast, and the false alarm probability is greatly reduced through the redundant coincidence judgment of three-out-of-two.
The signal gating circuit gates the alarm signal, and the logic buffer U21, the logic buffer U22 and the logic buffer U23 are all three-state buffers. Specifically, an enabling signal input end of the tri-state buffer is a failure signal input end, when the detector fails, a high-level failure signal is input by default, an alarm signal output end is forbidden, a channel fails (outputs a low-level normal signal), and the alarm signal of the channel cannot be output to the two-out-of-three alarm logic circuit.
In this embodiment, the detection range of the first GM probe 2-2 is 0.1 μ Gy/h to 0.5mGy/h, the detection range of the second GM probe 2-3 is 0.5mGy/h to 3Gy/h, and the detection range of the plastic flash probe 2-4 is 0.05Gy/h to 25 Gy/h.
During specific implementation, the plastic flash detectors 2-4 adopt a current integration mode to carry out radiation measurement, the rising time, the pulse width and the pulse amplitude of an integrated pulse comprise the time, the duration and the accumulated radiation intensity information of a critical accident, the anti-saturation capacity is strong, the upper limit of measurement is high, the magnitude of 0.05 Gy/h-25 Gy/h, the response speed is high, and instantaneous high-intensity radiation within 1ms can be detected in time; the first GM detector 2-2 and the second GM detector 2-3 are combined for measurement, the measurement range is wide, low-intensity radiation measurement is carried out, the radiation measurement is 0.1 mu Gy/h-3 Gy/h, and through the combined design of the first GM detector 2-2, the second GM detector 2-3 and the plastic flash detector 2-4, the advantages are complemented, the measurement range is wide, the radiation intensity is high, and the response is fast.
In this embodiment, the plastic flash detector 2-4 includes a plastic scintillator and a photomultiplier disposed on a side of the plastic scintillator, and the source detection LED2-5 is disposed on a photomultiplier tube base.
In specific implementation, the source detection LED2-5 is arranged on the photomultiplier high-voltage division circuit board and is conducted to the plastic scintillator collecting surface through the photomultiplier glass shell.
The alarm method of the nuclear critical alarm system comprises a critical accident monitoring alarm method and a checking method of the nuclear critical alarm system in the operation and maintenance process.
The critical accident monitoring and alarming method comprises the following specific steps:
step one, monitoring the gamma radiation dose rate at the installation position in real time by the first GM detector 2-2 and the second GM detector 2-3, and monitoring the critical accident at the installation position in real time by the plastic flash detector 2-4;
step two, the signal processing module 2-1 transmits the monitoring acquisition data of the first GM detector 2-2 and the second GM detector 2-3 to the display processing unit 1-3 of the radiation monitoring host 1 through an RS485 interface; the signal processing module 2-1 monitors the running state of the detector in real time and outputs a failure fault signal to the nuclear critical alarm logic unit 1-2;
step three, the display processing unit 1-3 processes signals of the first GM detector 2-2 and the second GM detector 2-3, and outputs an alarm signal to the nuclear critical alarm logic unit 1-2 when the signals are larger than an alarm threshold value;
step four, in the process of the step two to the step three, the electric signal output by the plastic flash detector 2-4 is divided into two paths after integral forming, one path is subjected to threshold value identification, the output signal is sent to a nuclear critical alarm logic unit 1-2 to be subjected to redundancy coincidence logic processing, and whether a critical accident occurs is judged; the other path of the pulse signals is transmitted to a detector signal acquisition and processing unit 1-1 in the radiation monitoring host 1 after differential conversion for pulse signal acquisition and recording;
during specific implementation, the radiation intensity measurement of the detector signal acquisition processing unit 1-1 and the alarm logic of the nuclear critical alarm logic unit 1-2 are processed in parallel to achieve the purpose of the fastest alarm response time, the nuclear critical alarm logic unit 1-2 adopts a hardware logic circuit to perform alarm judgment, the alarm response is output quickly, 10us magnitude processing is delayed, a 10ms magnitude relay outputs the alarm response, and the redundant coincidence judgment is performed by selecting 2 from 3, so that the false alarm probability is greatly reduced; the radiation intensity measurement adopts three-channel synchronous pulse signals to acquire at high speed, the sampling interval is 100us, the display refresh rate is 500 ms/time, and each screen can display the radiation pulse signals within the current 500 ms;
fifthly, the nuclear critical alarm logic unit 1-2 performs signal gating and two-out-of-three alarm discrimination through a hardware logic circuit, when the nuclear critical alarm logic unit 1-2 receives that the current channel detector running state signal is normal, the channel alarm signal can enter a two-out-of-three alarm logic circuit, and when the current channel detector running state signal is failure fault, the channel alarm signal cannot enter the two-out-of-three alarm logic circuit; when at least two paths of the three paths of signals received by the nuclear critical alarm logic unit 1-2 are alarm signals at the same time, outputting a critical alarm signal;
step six, when at least two composite detectors 2 in the plurality of composite detectors 2 trigger alarm at the same time, the alarm whistle 3 works; when parts of the composite detectors 2 fail and the rest two composite detectors 2 work normally, the two composite detectors 2 trigger alarm, and the alarm whistle 3 works; when a plurality of composite detectors 2 are partially failed and one of the remaining composite detectors 2 works normally, a signal of one composite detector 2 cannot be used for alarm judgment, and the alarm lamp whistle 3 does not work.
The specific process of the checking method for the nuclear critical alarm system in the operation and maintenance process comprises the following steps: the inspection signals are triggered manually and transmitted to the signal processing module 2-1 of each composite detector 2 through the radiation monitoring host 1, the signal processing module 2-1 excites the source detection LED2-5 to simulate plastic flash radiation fluorescent signals, critical accidents are simulated, and the composite detectors 2 detect signals simultaneously to give an alarm, so that the nuclear critical alarm system is inspected.
In specific implementation, the composite detector 2 is internally provided with a source detection LED to simulate plastic flash radiation fluorescent signals, the composite detectors 2 use the same excitation signal, the excitation signal parameters are adjustable, the state of each unit in the nuclear critical alarm system and the information of the function, the response time and the like of a full signal chain can be checked, and a user can conveniently perform simulated training and system check.
In this embodiment, the detector signal acquisition and processing unit 1-1 in the radiation monitoring host 1 adopts multi-channel parallel acquisition, simultaneously acquires and displays pulse waveforms of the plurality of composite detectors 2, and records measurement pulse waveforms within the duration of a critical accident, so as to be used for post-accident investigation and confirm the radiation intensity, the occurrence time and the duration of the critical accident.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims (10)
1. A nuclear critical alarm system comprises a radiation monitoring host (1), a plurality of composite detectors (2) connected with the radiation monitoring host (1), and an alarm whistle (3) connected with the output end of the radiation monitoring host (1); the method is characterized in that: the radiation monitoring host (1) comprises a detector signal acquisition processing unit (1-1), a nuclear critical alarm logic unit (1-2), a display processing unit (1-3) and power supply units (1-5) for supplying power to the power consumption units in the radiation monitoring host, wherein the detector signal acquisition processing unit (1-1), the nuclear critical alarm logic unit (1-2), the display processing unit (1-3) and the power supply units (1-5) are connected with one another through interface units (1-6), the composite detector (2) is connected with the detector signal acquisition processing unit (1-1) and the input end of the nuclear critical alarm logic unit (1-2) through the interface units (1-6), and the alarm whistle (3) is connected with the output end of the nuclear critical alarm logic unit (1-2) through the interface units (1-6) (ii) a
The compound detector (2) comprises a signal processing module (2-1), a first GM detector (2-2), a second GM detector (2-3), a plastic flash detector (2-4) and a source detection LED (2-5), wherein the first GM detector (2-2), the second GM detector (2-3) and the plastic flash detector (2-4) are all connected with the input end of the signal processing module (2-1), the output end of the signal processing module (2-1) is connected with a first high-voltage module (2-6) and a second high-voltage module (2-7), the first GM detector (2-2) and the second GM detector (2-3) are both connected with the output end of the first high-voltage module (2-6), the plastic flash detector (2-4) is connected with the output end of the second high-voltage module (2-7), the source detection LED (2-5) is connected with the output end of the signal processing module (2-1), the signal processing module (2-1) is connected with the detector signal acquisition processing unit (1-1), and the plastic flash detector (2-4) is connected with the input end of the nuclear critical alarm logic unit (1-2).
2. A nuclear criticality alarm system according to claim 1 wherein: the input end of the radiation monitoring host (1) is connected with an alarm manual releasing unit (4) arranged outside the withdrawing area.
3. A nuclear criticality alarm system according to claim 1 wherein: the number of the composite detectors (2) is at least three.
4. A nuclear criticality alarm system according to claim 1 wherein: the nuclear critical alarm logic unit (1-2) comprises a signal gating circuit and a two-out-of-three alarm logic circuit, wherein the signal gating circuit comprises a logic buffer U21, a logic buffer U22, a logic buffer U23, a resistor R112, a resistor R113 and a resistor R114, an enable signal input end STATE _1 of the logic buffer U21, an alarm signal input end EVENT1_ WD of the logic buffer U21, an enable signal input end STATE _2 of the logic buffer U22, an alarm signal input end EVENT2_ WD of the logic buffer U22, an enable signal input end STATE _3 of the logic buffer U23 and an alarm signal input end EVENT3_ WD of the logic buffer U23 are connected with a signal processing module (2-1) through interface units (1-6), an alarm signal output end N _ EVENT _1 of the logic buffer U21 is grounded through the resistor R112, an alarm signal output end N _ EVENT _2 of the logic buffer U22 is grounded through the resistor EVENT 113, the alarm signal output end N _ EVENT _3 of the logic buffer U23 is grounded through a resistor R114; the two-out-of-three alarm logic circuit comprises a NAND gate NAND1, a NAND gate NAND2, a NAND gate NAND3 AND an AND gate AND1, two input ends of the NAND gate 1 are respectively connected with the alarm signal output end N _ EVENT _1 of the logic buffer U21 and the alarm signal output end N _ EVENT _2 of the logic buffer U22, two input ends of the NAND gate 2 are respectively connected with the alarm signal output end N _ EVENT _2 of the logic buffer U22 and the alarm signal output end N _ EVENT _3 of the logic buffer U23, two input ends of the NAND gate 3 are respectively connected with the alarm signal output end N _ EVENT _1 of the logic buffer U21 and the alarm signal output end N _ EVENT _3 of the logic buffer U23, the output end of the NAND gate 1, the output end of the NAND gate 2 AND the output end of the NAND gate 3 are respectively connected with three input ends of an AND gate 1, the output end of the AND gate AND1 is the alarm signal output end BJR of the two-out-of-three alarm logic circuit.
5. A nuclear criticality alarm system according to claim 1 wherein: the detection range of the first GM detector (2-2) is 0.1 mu Gy/h-0.5 mGy/h, the detection range of the second GM detector (2-3) is 0.5 mGy/h-3 Gy/h, and the detection range of the plastic flash detector (2-4) is 0.05 Gy/h-25 Gy/h.
6. A nuclear criticality alarm system according to claim 1 wherein: the plastic flash detector (2-4) comprises a plastic scintillator and a photomultiplier arranged on the side face of the plastic scintillator, and the source detection LED (2-5) is arranged on a photomultiplier tube seat.
7. An alarm method of a nuclear critical alarm system is characterized in that: the alarm system of claim 1-6 is adopted, and comprises a critical accident monitoring alarm method and a checking method for a nuclear critical alarm system in an operation and maintenance process.
8. The method of claim 7, wherein the critical accident monitoring alarm method comprises the following steps:
step one, the first GM detector (2-2) and the second GM detector (2-3) monitor the gamma radiation dose rate at the installation position in real time, and the plastic flash detector (2-4) monitors the critical accident at the installation position in real time;
transmitting the monitoring acquisition data of the first GM detector (2-2) and the second GM detector (2-3) to a display processing unit (1-3) of the radiation monitoring host (1) through an RS485 interface by the signal processing module (2-1); the signal processing module (2-1) monitors the running state of the detector in real time and outputs a failure fault signal to the nuclear critical alarm logic unit (1-2);
thirdly, the display processing unit (1-3) processes signals of the first GM detector (2-2) and the second GM detector (2-3), and when the signals are larger than an alarm threshold value, an alarm signal is output to the nuclear critical alarm logic unit (1-2);
step four, in the process of the step two to the step three, the electric signal output by the plastic flash detector (2-4) is divided into two paths after integral forming, one path is subjected to threshold value identification, the output signal is sent to a nuclear critical alarm logic unit (1-2) to be subjected to redundancy coincidence logic processing, and whether a critical accident occurs is judged; the other path of the pulse signals is transmitted to a detector signal acquisition and processing unit (1-1) in the radiation monitoring host (1) after differential conversion for pulse signal acquisition and recording;
fifthly, the nuclear critical alarm logic unit (1-2) performs signal gating and two-out-of-three alarm discrimination through a hardware logic circuit, when the nuclear critical alarm logic unit (1-2) receives that the current channel detector running state signal is normal, the channel alarm signal can enter the two-out-of-three alarm logic circuit, and when the current channel detector running state signal is failure fault, the channel alarm signal cannot enter the two-out-of-three alarm logic circuit; when at least two paths of the three paths of signals received by the nuclear critical alarm logic unit (1-2) are alarm signals at the same time, outputting a critical alarm signal;
sixthly, when at least two composite detectors (2) in the plurality of composite detectors (2) trigger alarm at the same time, the alarm whistle (3) works; when parts of the composite detectors (2) fail and the rest two composite detectors (2) work normally, the two composite detectors (2) trigger alarm and the alarm whistle (3) works; when a plurality of composite detectors (2) are partially failed and one of the remaining composite detectors (2) works normally, a signal of one composite detector (2) cannot be used for alarm judgment, and the alarm whistle (3) does not work.
9. The method for alarming of the nuclear critical alarm system as claimed in claim 7, wherein the specific process of the method for checking the nuclear critical alarm system in the operation and maintenance process comprises: the detection signals are triggered manually, the detection signals are transmitted to the signal processing module (2-1) of each composite detector (2) through the radiation monitoring host (1), the signal processing module (2-1) excites the source detection LED (2-5) to simulate plastic flash radiation fluorescent signals, critical accidents are simulated, and the composite detectors (2) detect signals simultaneously to give an alarm, so that the nuclear critical alarm system is detected.
10. The alarm method of the nuclear critical alarm system according to claim 7, characterized in that the detector signal acquisition processing unit (1-1) in the radiation monitoring host (1) adopts multi-channel parallel acquisition, simultaneously acquires and displays pulse waveforms of a plurality of composite detectors (2), and records the measured pulse waveforms within the critical accident duration for post-accident investigation to confirm the radiation intensity, the occurrence time and the duration of the critical accident.
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Denomination of invention: A critical alarm system and its method Effective date of registration: 20220328 Granted publication date: 20220125 Pledgee: Xi'an Science and Technology Financial Service Center Co.,Ltd. Pledgor: SHAANXI WEIFENG NUCLEAR INSTRUMENT Inc. Registration number: Y2022610000112 |