Nuclear reactor high-frequency pulse counting device

Abstract

The invention discloses a nuclear reactor high-frequency pulse counting device which is arranged in a nuclear measurement system outside a reactor, and the high-frequency pulse counting device is connected to a DCS (Distributed Control System) platform; the device comprises 8 pulse quantity input channels and 16 switching value input channels. The pulse quantity input channel and the switching value input channel are respectively provided with a self-diagnosis circuit, and diagnosis results obtained through the self-diagnosis circuits are fed back to the main control unit and are displayed through a device indicating lamp. The pulse quantity input channel has a pulse accumulation judgment algorithm, and accumulation parameters are adjusted according to detector parameters and actual test data; the device can collect high-frequency pulse signals output by a source range neutron detector, and can collect frequency signals output by a middle range neutron detector and a power range neutron detector after conditioning and frequency signals output by a primary loop main pump tachometer and a conditioning circuit at the same time. According to the invention, the application requirements of various pulse and frequency recording scenes can be met.

Description

Technical Field

[0001] The invention relates to the field of nuclear information acquisition and processing, and in particular to a nuclear reactor high-frequency pulse counting device. Background Art

[0002] The Reactor Nuclear Instrumentation System (RNI) includes three neutron detection channels: source range, intermediate range and power range. When the three detectors are used in combination, they can more accurately detect the neutron injection rate and neutron multiplication period during reactor refueling, startup, shutdown and power operation. At the same time, when the neutron injection rate and neutron number change rate are abnormal at any stage, an alarm signal can be output to the Reactor Protection System (RPR) or a shutdown signal can be output to the ATWT.

[0003] In RNI, the source range detector outputs a random pulse signal; the intermediate range detector outputs a weak current (as low as 10 -12 A) can be converted into a frequency signal through a transimpedance amplifier circuit combined with a VF circuit, where the frequency value is proportional to the current value; the narrow range current signal output by the power range can be directly and accurately converted into a frequency signal through an IF circuit, where the frequency value is proportional to the current value.

[0004] The traditional back-end acquisition equipment is as follows: use a calibrator to collect the pulse signal output by the source range detector; use ADCs with different resolutions to collect the voltage signal or frequency signal output by the conditioning circuits of the other two detectors. The traditional method uses independent recording devices, which cannot achieve synchronization in terms of time information and system integration applications; too many electronic devices bring maintenance difficulties and inconvenience in operation. Independent acquisition equipment cannot be effectively compatible with the DCS platform, and cannot be uniformly managed, downloaded, and monitored in actual engineering applications.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The purpose of the present invention is to provide a high-frequency pulse counting device for a nuclear reactor. A universal pulse and frequency acquisition circuit is designed based on the three range conditioning circuits of RNI, and it is compatible with DCS platform applications. For high-frequency pulse applications, the device also has functions such as pulse accumulation rejection, acquisition channel enablement, channel diagnosis, and online configuration of channel parameters. The present invention can meet the application requirements of various pulse and frequency recording scenarios, and greatly simplifies the operation and maintenance difficulty of application engineers. This device can also be used in the primary circuit main pump speed measurement scenario, and the accuracy index is fully compatible with the main pump speed requirements.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention provides a high-frequency pulse counting device for a nuclear reactor, which is arranged in a nuclear measurement system outside the reactor and connected to a DCS platform; the high-frequency pulse counting device includes 8 pulse quantity input channels and 16 switch quantity input channels;

[0009] Both the pulse quantity input channel and the switch quantity input channel are equipped with self-diagnosis circuits. The diagnosis results obtained through the self-diagnosis circuits are fed back to the main control unit MCU and displayed through the device indicator light;

[0010] The pulse quantity input channel is equipped with a pulse accumulation judgment algorithm, and the accumulation parameters are adjusted according to the detector parameters and actual test data;

[0011] The high-frequency pulse counting device can collect the high-frequency pulse signal output by the source range neutron detector, and can also collect the frequency signal output by the intermediate range neutron detector and the power range neutron detector after conditioning, and the frequency signal output by the primary circuit main pump speed meter and the conditioning circuit.

[0012] Furthermore, the high-frequency pulse counting device is compatible with the DCS platform, and the working parameters can be monitored and downloaded online by the engineer station.

[0013] Furthermore, the high-frequency pulse counting device and the DCS platform use the same system on chip, the communication channel of the high-frequency pulse counting device uses the same hardware connector and software communication protocol as the DCS platform, and the internal control instructions and communication data packet format of the high-frequency pulse counting device are the same as those of the DCS platform.

[0014] Furthermore, the 8-way pulse quantity input channel realizes independent diagnosis by using the mode of the main control unit MCU and the solid-state relay; each pulse quantity input channel includes a first solid-state relay, a second solid-state relay and a bidirectional digital isolator; the working status of the pulse quantity input channel includes:

[0015] The first acquisition state: when the control signal sent by the main control unit MCU is a pulse quantity acquisition signal, the first solid-state relay is controlled to be closed and the second solid-state relay is disconnected, one end of the first solid-state relay is connected to the external high-frequency pulse signal, and the other end of the first solid-state relay is connected to the bidirectional digital isolator, and the high-frequency pulse signal input by the pulse quantity input channel is transmitted to the main control unit MCU through the bidirectional digital isolator;

[0016] First diagnostic state: when the control signal sent by the main control unit MCU is a pulse diagnostic signal, the first solid-state relay is controlled to be disconnected and the second solid-state relay is controlled to be closed, one end of the second solid-state relay is connected to a bidirectional digital isolator, and the other end of the second solid-state relay is also connected to a bidirectional digital isolator. The main control unit MCU collects the diagnostic signal and compares it with the output diagnostic signal.

[0017] Further, the VDD1 pin of the bidirectional digital isolator is connected to the +5V_CH1 power supply, the OUTA pin of the bidirectional digital isolator is connected to the fourth terminal of the second solid-state relay, the INB pin of the bidirectional digital isolator is connected to the third terminal of the second solid-state relay, the INB pin of the bidirectional digital isolator is also connected to the fourth terminal of the first solid-state relay, the GND1 terminal and the GND2 terminal of the bidirectional digital isolator are both grounded, the OUTB pin of the bidirectional digital isolator serves as the output CH1, the INA pin of the bidirectional digital isolator accesses the control signal MCU_TEST+ of the main control unit MCU, and the VDD2 pin of the bidirectional digital isolator is connected to the +3P3V_CPU power supply;

[0018] The first terminal of the second solid-state relay is connected to the second terminal of the second solid-state relay through the capacitor C1, and the inductor L1 is connected in parallel across both ends of the capacitor C1; one end of the inductor L1 is grounded and the other end accesses the digital quantity signal CH1_TEST+; the first terminal of the first solid-state relay is connected to the second terminal of the first solid-state relay through the capacitor C2, and the inductor L2 is connected in parallel across both ends of the capacitor C2; one end of the inductor L2 is grounded and the other end accesses the digital quantity signal CH1_EN; the third terminal of the first solid-state relay accesses the externally input pulse quantity signal CH1.

[0019] For the first solid-state relay and the second solid-state relay, their first terminal is the power supply terminal (or the positive pole of the control terminal), the second terminal is the power supply ground terminal (or the negative pole of the control terminal), and the third terminal and the fourth terminal are both contact terminals (dry contacts, without direction).

[0020] Further, the model of the bidirectional digital isolator is NSi8121N1, and the models of the first solid-state relay and the second solid-state relay are both BC008BS.

[0021] Further, the digital quantity input channel realizes a configurable diagnostic mode by using the main control unit MCU, the multiplexer, and the mode of the solid-state relay; each digital quantity input channel includes a third solid-state relay, a fourth solid-state relay, and an optocoupler; the working states of the digital quantity input channel include:

[0022] The second acquisition state: When the control signal issued by the main control unit MCU is the digital quantity acquisition signal, the opening of the digital quantity input channel is controlled by the main control unit MCU for the third solid-state relay. When the digital quantity input channel is working properly, the third solid-state relay is closed, the fourth solid-state relay is opened, and the optocoupler acquires the external contact signal;

[0023] The second diagnostic state: when the control signal sent by the main control unit MCU is a switch quantity diagnostic signal, the third solid-state relay of the switch quantity input channel is disconnected, the optocoupler is disconnected from the external dry contact, and the diagnostic state is entered; the fourth solid-state relay for diagnosis is closed and opened by the main control unit MCU. At this time, the main control unit MCU reads back the switch quantity state and compares it with the control signal of the main control unit MCU. If the states are consistent, it means that the switch quantity input channel is normal; if the states are inconsistent, it means that the switch quantity input channel is abnormal.

[0024] Furthermore, the 8 pulse quantity input channels are isolated from the reactor external nuclear measurement system, and the pulse quantity input channels are isolated from each other;

[0025] The 16-way switch input channels are isolated from the reactor's external nuclear measurement system.

[0026] Furthermore, the high-frequency pulse signals acquired by the 8-way pulse quantity input channels are time-stamped inside the main control unit MCU, and the time stamps respectively represent the pulse rising edge time and falling edge time, and the time resolution is less than or equal to 10ns.

[0027] Furthermore, the high-frequency pulse counting device is used in applications such as reactor nuclear instrument systems, detector arrays, and main pump speed measurement.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] The present invention discloses a high-frequency pulse counting device for a nuclear reactor, which can collect pulse and frequency signals output by a neutron detector. It comprises a total of 8 mutually isolated pulse quantity input channels and 16 isolated DI channels, and all channels have a channel self-diagnosis function. The pulse quantity input channel has a pulse accumulation judgment function, and can timestamp the rising edge and falling edge of the pulse quantity. The module is compatible with the DCS platform, and the configuration of nuclear instrument systems of different reactor types can be completed under the same engineer station. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0031] Figure 1 It is a structural schematic diagram of a nuclear reactor high frequency pulse counting device of the present invention;

[0032] Figure 2 This is the principle diagram of the pulse quantity input circuit of the present invention;

[0033] Figure 3 This is a schematic diagram of the diagnostic circuit of the pulse quantity input channel of the present invention;

[0034] Figure 4 This is the schematic diagram of the switch input channel circuit of the present invention. DETAILED DESCRIPTION

[0035] Hereinafter, the term "include" or "may include" used in various embodiments of the present invention indicates the presence of the invented function, operation or element, and does not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present invention, the terms "include", "have" and their cognates are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0036] In various embodiments of the present invention, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the words listed at the same time. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0037] The expressions (such as "first", "second", etc.) used in various embodiments of the present invention may modify the various constituent elements in various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing an element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of various embodiments of the present invention, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0038] It should be noted that if it is described that one component element is “connected” to another component element, the first component element may be directly connected to the second component element, and a third component element may be “connected” between the first component element and the second component element. Conversely, when one component element is “directly connected” to another component element, it can be understood that there is no third component element between the first component element and the second component element.

[0039] The terms used in various embodiments of the present invention are only used for the purpose of describing specific embodiments and are not intended to limit various embodiments of the present invention. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as the meaning generally understood by those of ordinary skill in the art to which the various embodiments of the present invention belong. The terms (such as the terms defined in the dictionary generally used) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly defined in various embodiments of the present invention.

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0041] The present invention specifically relates to a nuclear pulse counting device at the rear end of a nuclear detector. The specific application field is the output signals of the three-range detectors of the reactor nuclear instrument system. The high-frequency pulse counting module is a multi-channel, cascade-usable general device suitable for recording the frequency signals and random pulse signals output by the three-range detectors of the nuclear instrument system, the reactor main pump and other equipment.

[0042] The high-frequency pulse counting device designed in the present invention can simultaneously collect the random pulse signal output by the source range detector, and can also collect the frequency signal output by the other two detectors after conditioning. While simultaneously meeting the requirements of recording the output signals of the three detectors, it is perfectly compatible with the DCS platform, which makes RNI no longer independent of RPR, but can be used as a configurable part of DCS, further expanding the application scenarios of DCS and improving the work and maintenance efficiency of nuclear power plant equipment. And all devices are domestically produced.

[0043] Specific design points include:

[0044] (1) High-frequency pulse isolation input

[0045] High-speed optocouplers are used to optically isolate input pulses and frequency signals. This is an improvement on the switch input (DI) channel in the control system. In comparison, the isolated input in this design can effectively respond to pulse signals up to 10MHz, which is faster than the traditional DI channel. Optical isolation can effectively protect the front-end detector from being broken down by high voltage and destroying the entire circuit.

[0046] (2) 8 isolated pulse input channels

[0047] The high-frequency pulse counting device provides a total of 8 pulse quantity input channels, and each pulse quantity channel is isolated from each other. When used to simultaneously record the output signals of multiple detectors, it can effectively avoid the mutual influence caused by the simultaneous use of multiple detectors.

[0048] When multiple channels work simultaneously, they share the same clock system, which can effectively realize the time correlation of the output pulses of different detectors. This is very suitable for coincidence and anti-coincidence application scenarios in radiation detection.

[0049] (3) 16-way digital input (DI) channels

[0050] Based on the 8-channel pulse input channel, 16 DI channels are designed, and all DI channels are isolated by optical coupling. The design of DI channels provides a wide range of control methods for the entire electronics. The application scenarios of DI channels combined with pulse channels are as follows:

[0051] 1) The DI channel is used as the enable signal of the pulse channel, and the working time of different pulse channels is controlled in real time by the main control. When 8 pulse channels are used for the detector array, the DI enable signal can complete the function of timing the opening of the pulse channel according to the physical model of the actual array.

[0052] 2) DI channel can be used as external enable input to control the working state of the entire module. When multiple high-frequency pulse counting devices are used in conjunction, DI channel can realize multi-module synchronous timing mark within a certain time accuracy. This approach has higher time accuracy than the method of sending through the master control.

[0053] (4) Online diagnosis of all channels

[0054] The 8-way pulse input channel and 16-way DI channel are designed with independent diagnostic circuits, which can realize the channel diagnostic function in real time and configurably, and display the diagnostic structure through the panel indicator light, and report the diagnostic results to the main control. Among them, the 8-way pulse channel uses the MCU+solid-state relay mode to realize independent diagnosis; the DI channel uses the MCU+multiplexer+solid-state relay mode to realize the configurable diagnostic mode.

[0055] (5) Pulse accumulation judgment

[0056] For the first time, the pulse pile-up judgment algorithm was applied to gas neutron detectors. Common pile-up judgment methods are used in digital multi-channel radiation detection systems. Most of the judgment methods use different pulse shapes to distinguish whether pile-up occurs. This method requires the use of expensive and relatively complex analog-to-digital converters (ADCs).

[0057] The detector in this design is a gas neutron detector, whose physical process is different from that of a scintillator detector, and the physical process of a boron-containing proportional counter tube is also different. This design collects the duration of each pulse without using ADC for shape collection and judgment, and recognizes the accumulation state by judging the pulse width.

[0058] (6) Based on DCS platform

[0059] The traditional reactor nuclear instrumentation system is independent of the reactor protection system, but this design is based on the DCS platform and uses the same system-on-chip as the platform. Its communication channel uses the same hardware connector and software communication protocol as the DCS. At the same time, the internal control instructions and communication data packet formats are the same as the DCS, so the application program can be downloaded and monitored through the same engineer station. The application in nuclear power plants has greatly improved the operator's experience and simplified the maintenance and downloading process. As a universal platform, it can be used for out-of-core nuclear measurement applications with different reactor types and different detector combinations.

[0060] (7) Extended Application

[0061] The speed meter of the main pump in the primary circuit of the reactor outputs a frequency signal related to the speed, and the frequency measurement accuracy requirement is as high as 0.1%. The accuracy of the high-frequency pulse counting device can reach the following indicators: when the frequency is greater than 1000, the accuracy can be less than 0.1%, and when the frequency is less than 1000, the accuracy is less than 2 false counts. The accuracy indicators of the entire device completely cover the accuracy requirements of the main pump speed measurement. And the pulse input channel has a high response speed, which can fully meet the pulse frequency output by the main pump output meter.

[0062] (8) SOE Application

[0063] The high-frequency pulse counting module can add a time stamp to the rising and falling edges of each pulse signal recorded, with a time resolution of less than or equal to 100ns. This function allows the block to be used as an SOE module in DCS. It provides the reactor nuclear instrumentation system and the reactor protection system with the time recording capability under accident conditions. When the reactor has an abnormal neutron injection rate or an abnormal neutron number change rate, the module outputs an alarm or even a shutdown signal to the protection system, and includes the exact time when the abnormal signal arrives. It provides a time basis for nuclear power plant operators to analyze the cause of the accident.

[0064] The present invention cooperates with the safety-level DCS platform and the detector preamplifier to form an outer core measurement channel, which is used to monitor the neutron information leaked from the core during reactor startup, operation, shutdown and after an accident.

[0065] Example 1

[0066] like Figure 1As shown, the present invention provides a high-frequency pulse counting device for a nuclear reactor. The high-frequency pulse counting device is arranged in a nuclear measurement system outside the reactor, and the high-frequency pulse counting device is connected to a DCS platform. The high-frequency pulse counting device is used in applications such as reactor nuclear instrument systems, detector arrays, and main pump speed measurement.

[0067] The high-frequency pulse counting device includes 8 pulse quantity input channels and 16 switch quantity input channels;

[0068] Both the pulse quantity input channel and the switch quantity input channel are equipped with self-diagnosis circuits. The diagnosis results obtained through the self-diagnosis circuits are fed back to the main control unit MCU and displayed through the device indicator light;

[0069] The pulse quantity input channel is equipped with a pulse accumulation judgment algorithm, and the accumulation parameters are adjusted according to the detector parameters and actual test data;

[0070] The high-frequency pulse counting device can collect the high-frequency pulse signal output by the source range neutron detector, and can also collect the frequency signal output by the intermediate range neutron detector and the power range neutron detector after conditioning, and the frequency signal output by the primary circuit main pump speed meter and the conditioning circuit.

[0071] In this embodiment, the signals input by the 8-way pulse input channel are high-frequency pulse signals input by the previous stage, and the high-frequency pulse signals adopt the COMS level standard (VIH ≥ 3.5V, VIL ≤ 1.5). There are two types of high-frequency pulse signals, namely random pulse signals and periodic pulse signals. The input range of the random pulse signal is 0Mcps to 10Mcps, and the width of the pulse is 200ns to 500ns. The input frequency range of the periodic pulse signal is 0Hz to 10MHz.

[0072] The pulse input channel and the system use a high-speed digital isolation chip to electrically isolate the input signal. According to the parameters of the input signal, the chip model NSi8121N1 is selected. The power supply range of this chip is 2.5V~5.5V, the operating temperature is -40℃~125℃, the electrical isolation is 5000Vrms (min), the transmission delay time is 10ns (MAX), the rise time is 5ns (MAX), and the fall time is 5ns (MAX), which meets the design requirements. The specific circuit is as follows Figure 2 shown.

[0073] In the existing common design, the pulse quantity is directly input to the IO pin of the MCU. For this reason, a safer design is to use an optocoupler or a relay to isolate the input pulse quantity. However, the optocoupler is only one-way and cannot output a self-test signal in the opposite direction. If self-test needs to be configured, two chips need to be placed. At the same time, the optocoupler response time is usually in microseconds, which cannot meet the pulse signal isolation transmission requirements of up to 10Mcps. Therefore, in response to the above existing problems, the present invention cleverly uses a digital isolation chip to achieve bidirectional pulse signal isolation, and uses the isolation chip originally designed for digital communication to transmit analog pulse models. On the one hand, a single bidirectional digital isolation chip can save space and cost, and improve reliability compared to using two optocouplers; on the other hand, the digital isolation chip uses magnetic isolation technology, which has a longer service life than the optical isolation technology of the optocoupler. In addition, this design takes into account the fast response time capability of the digital isolation chip, and its corresponding time is ns, which is thousands of times higher than that of ordinary optocouplers, so that the design can meet the 10Mcps pulse signal isolation transmission requirements. The entire design has new functions of isolation and self-test compared to the commonly used design, and has a high-speed new function of responding to high-frequency pulses compared to the commonly used design.

[0074] Specifically, the 8-way pulse quantity input channel realizes independent diagnosis by using the mode of the main control unit MCU and the solid-state relay; each pulse quantity input channel includes a first solid-state relay, a second solid-state relay and a bidirectional digital isolator, the model of the bidirectional digital isolator is NSi8121N1, and the models of the first solid-state relay and the second solid-state relay are both BC008BS.

[0075] The VDD1 pin of the bidirectional digital isolator is connected to the +5V_CH1 power supply, the OUTA pin of the bidirectional digital isolator is connected to the fourth terminal of the second solid-state relay, the INB pin of the bidirectional digital isolator is connected to the third terminal of the second solid-state relay, the INB pin of the bidirectional digital isolator is also connected to the fourth terminal of the first solid-state relay, the GND1 terminal and the GND2 terminal of the bidirectional digital isolator are both grounded, the OUTB pin of the bidirectional digital isolator is used as the output CH1, the INA pin of the bidirectional digital isolator is connected to the control signal MCU_TEST+ of the main control unit MCU, and the VDD2 pin of the bidirectional digital isolator is connected to the +3P3V_CPU power supply;

[0076] The first end of the second solid-state relay is connected to the second end of the second solid-state relay through the capacitor C1, and the inductor L1 is connected in parallel to both ends of the capacitor C1; one end of the inductor L1 is grounded, and the other end is connected to the switch signal CH1_TEST+; the first end of the first solid-state relay is connected to the second end of the first solid-state relay through the capacitor C2, and the inductor L2 is connected in parallel to both ends of the capacitor C2; one end of the inductor L2 is grounded, and the other end is connected to the switch signal CH1_EN; the third end of the first solid-state relay is connected to the external input pulse signal CH1.

[0077] Among them, for the first solid-state relay and the second solid-state relay, the first end is the power supply end (or the positive pole of the control end), the second end is the power ground end (or the negative pole of the control end), and the third end and the fourth end are both contact ends (dry contacts, no direction).

[0078] Based on the above circuit design, in order to ensure the reliability of the channel, the channel needs to be diagnosed regularly. During the diagnosis process, the MCU is first used to control the first solid-state relay before the input channel to be cut off, and at the same time, the second solid-state relay of the diagnostic channel is closed to input the diagnostic signal. The diagnostic signal is given by the MCU, and the channel and the system are isolated from each other through the digital isolation chip. The MCU samples the diagnostic signal and compares it with the output diagnostic signal. After the diagnosis is completed, the MCU is first used to control the second solid-state relay before the input channel to be cut off, and at the same time, the first solid-state relay of the diagnostic channel is closed to input the external pulse signal. The specific circuit is as follows: Figure 3 shown.

[0079] Specifically, the working status of the pulse quantity input channel includes:

[0080] The first acquisition state: when the control signal sent by the main control unit MCU is a pulse quantity acquisition signal, the first solid-state relay is controlled to be closed and the second solid-state relay is disconnected, one end of the first solid-state relay is connected to the external high-frequency pulse signal, and the other end of the first solid-state relay is connected to the bidirectional digital isolator, and the high-frequency pulse signal input by the pulse quantity input channel is transmitted to the main control unit MCU through the bidirectional digital isolator;

[0081] The first diagnostic state: when the control signal sent by the main control unit MCU is a pulse diagnostic signal, the first solid-state relay is controlled to be disconnected and the second solid-state relay is controlled to be closed. One end of the second solid-state relay is connected to the bidirectional digital isolator, and the other end of the second solid-state relay is also connected to the bidirectional digital isolator. The main control unit MCU collects the diagnostic signal and compares it with the output diagnostic signal. After the diagnosis is completed, the main control unit MCU first controls the second solid-state relay in front of the input channel to be cut off, and at the same time closes the first solid-state relay of the diagnostic channel to input an external high-frequency pulse signal.

[0082] In this embodiment, the switch input is a dry contact signal, so an external power supply is required to convert the dry contact into a wet contact, and the contact signal is collected by an optical coupler to achieve channel isolation of the system. The optical coupler selects the OR-3H7C model to meet the isolation requirements of the design. In order to ensure the safety of the interface, a board is used to power the contacts with +24V. Since the 16 dry contacts do not need to be isolated from each other, in order to simplify the circuit, the 16 contacts share the same +24V power supply and are grounded externally. The signal collected by the secondary side of the optical coupler is directly input into the MCU for status collection.

[0083] A resistor is connected in series on the primary side of the optocoupler to limit the current and reduce power consumption. A self-recovery fuse and a TVS tube are connected in parallel at the interface to protect against transient voltage and current. The channel is opened by controlling the solid-state relay BC008BS through the MCU. When the channel is working normally, the third solid-state relay is closed and the optocoupler collects external contact signals. When the channel enters the diagnostic state, the fourth solid-state relay is disconnected. The specific circuit is as follows Figure 4 shown.

[0084] Specifically, the switch input channel uses the main control unit MCU, multiplexer and solid-state relay mode to realize the configurable diagnostic mode; each switch input channel includes a third solid-state relay, a fourth solid-state relay and an optical coupler; the third solid-state relay and the fourth solid-state relay are both BC008BS, and the optical coupler is OR-3H7C. The specific connection relationship of each device is as follows Figure 4 shown.

[0085] In order to ensure the reliability of the switch input channel, it is necessary to diagnose the channel regularly. The working status of the switch input channel includes:

[0086] Second acquisition state: when the control signal sent by the main control unit MCU is a switch quantity acquisition signal, the opening of the switch quantity input channel controls the third solid-state relay through the main control unit MCU. When the switch quantity input channel works normally, the third solid-state relay is closed, the fourth solid-state relay is disconnected, and the optocoupler collects the external contact signal;

[0087] The second diagnostic state: when the control signal sent by the main control unit MCU is a switch quantity diagnostic signal, the third solid-state relay of the switch quantity input channel is disconnected, the optocoupler is disconnected from the external dry contact, and the diagnostic state is entered; the fourth solid-state relay for diagnosis is closed and opened by the main control unit MCU. At this time, the main control unit MCU reads back the switch quantity state and compares it with the control signal of the main control unit MCU. If the states are consistent, it means that the switch quantity input channel is normal; if the states are inconsistent, it means that the switch quantity input channel is abnormal.

[0088] As a further implementation, the high-frequency pulse counting device is compatible with the DCS platform, and the engineer station monitors and downloads the working parameters online. Specifically, the high-frequency pulse counting device and the DCS platform use the same system on chip, and the communication channel of the high-frequency pulse counting device uses the same hardware connector and software communication protocol as the DCS platform. At the same time, the internal control instructions and communication data packet format of the high-frequency pulse counting device are the same as those of the DCS platform.

[0089] In the actual application process of the above technical solution, the nuclear instrumentation system (RNI) and the reactor protection system (RPR) can be monitored, operated, and downloaded using the same platform. Coordination between the two systems is achieved, making it more convenient for nuclear power plant operators to monitor and operate the reactor operation parameters in real time.

[0090] As a further implementation, the 8-channel pulse quantity input channels are isolated from the out-of-reactor nuclear measurement system of the reactor, and each pulse quantity input channel is isolated from each other.

[0091] As a further implementation, the 16-channel digital input channels are isolated from the out-of-reactor nuclear measurement system of the reactor.

[0092] As a further implementation, the 16-channel digital inputs can be used as the enabling signals for the pulse quantity channels, enabling multiple high-frequency pulse counting devices to be used jointly.

[0093] As a further implementation, the 16-channel digital inputs can be used as the enabling signals for the pulse quantity channels, enabling all pulse quantity channels to perform application programming according to the occurrence order of nuclear events by the detector array.

[0094] As a further implementation, the 8-channel pulse quantity input channels have a pulse pile-up judgment function, which identifies pulse pile-up based on the pulse width for the pulse signals output by the gas detectors, and can online adjust the parameters of this function according to the physical processes and on-site results of different detectors.

[0095] As a further implementation, the high-frequency pulse signals obtained by the 8-channel pulse quantity input channels are timestamped inside the main control unit MCU. The timestamps respectively represent the pulse rising edge time and falling edge time, and the time resolution is less than or equal to 10 ns.

[0096] The above specific implementation manners further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only the specific implementation manners of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A nuclear reactor high frequency pulse counting device, characterized in that: The high-frequency pulse counting device is arranged in the reactor external nuclear measurement system, and the high-frequency pulse counting device is connected to the DCS platform; the high-frequency pulse counting device includes 8 pulse quantity input channels and 16 switch quantity input channels; The pulse quantity input channel and the switch quantity input channel are both provided with a self-diagnosis circuit, and the diagnosis result obtained by the self-diagnosis circuit is fed back to the main control unit and displayed by the device indicator light; The pulse quantity input channel is provided with a pulse accumulation judgment algorithm, and the accumulation parameters are adjusted according to the detector parameters and actual test data; The high-frequency pulse counting device can collect the high-frequency pulse signal output by the source range neutron detector, and can also collect the frequency signal output by the intermediate range neutron detector and the power range neutron detector after conditioning, and the frequency signal output by the primary circuit main pump speed meter and the conditioning circuit.

2. A nuclear reactor high frequency pulse counting device according to claim 1, characterized in that: The high-frequency pulse counting device is compatible with the DCS platform, and the working parameters can be monitored and downloaded online by the engineer station.

3. A nuclear reactor high frequency pulse counting device according to claim 2, characterized in that: The high-frequency pulse counting device and the DCS platform use the same system on chip, and the communication channel of the high-frequency pulse counting device uses the same hardware connector and software communication protocol as the DCS platform. At the same time, the internal control instructions and communication data packet format of the high-frequency pulse counting device are the same as those of the DCS platform.

4. A nuclear reactor high frequency pulse counting device according to claim 1, characterized in that: The 8 pulse input channels use the main control unit and solid-state relay mode to achieve independent diagnosis; each pulse input channel includes a first solid-state relay, a second solid-state relay and a bidirectional digital isolator; the working status of the pulse input channel includes: First acquisition state: when the control signal sent by the main control unit is a pulse quantity acquisition signal, the first solid-state relay is controlled to be closed and the second solid-state relay is controlled to be disconnected, one end of the first solid-state relay is connected to an external high-frequency pulse signal, and the other end of the first solid-state relay is connected to a bidirectional digital isolator, and the high-frequency pulse signal input by the pulse quantity input channel is transmitted to the main control unit through the bidirectional digital isolator; First diagnostic state: when the control signal sent by the main control unit is a pulse diagnostic signal, the first solid-state relay is controlled to be disconnected and the second solid-state relay is controlled to be closed, one end of the second solid-state relay is connected to a bidirectional digital isolator, and the other end of the second solid-state relay is also connected to a bidirectional digital isolator. The main control unit collects the diagnostic signal and compares it with the output diagnostic signal.

5. A nuclear reactor high frequency pulse counting device according to claim 4, characterized in that: The VDD1 pin of the bidirectional digital isolator is connected to the +5V_CH1 power supply, the OUTA pin of the bidirectional digital isolator is connected to the fourth end of the second solid-state relay, the INB pin of the bidirectional digital isolator is connected to the third end of the second solid-state relay, the INB pin of the bidirectional digital isolator is also connected to the fourth end of the first solid-state relay, the GND1 end and the GND2 end of the bidirectional digital isolator are both grounded, the OUTB pin of the bidirectional digital isolator is used as the output CH1, the INA pin of the bidirectional digital isolator is connected to the control signal MCU_TEST+ of the main control unit MCU, and the VDD2 pin of the bidirectional digital isolator is connected to the +3P3V_CPU power supply; The first end of the second solid-state relay is connected to the second end of the second solid-state relay through the capacitor C1, and the inductor L1 is connected in parallel to both ends of the capacitor C1; one end of the inductor L1 is grounded, and the other end is connected to the switch signal CH1_TEST+; the first end of the first solid-state relay is connected to the second end of the first solid-state relay through the capacitor C2, and the inductor L2 is connected in parallel to both ends of the capacitor C2; one end of the inductor L2 is grounded, and the other end is connected to the switch signal CH1_EN; the third end of the first solid-state relay is connected to the external input pulse signal CH1.

6. A nuclear reactor high frequency pulse counting device according to claim 5, characterized in that: The model of the bidirectional digital isolator is NSi8121N1, and the model of the first solid-state relay and the second solid-state relay are both BC008BS.

7. A nuclear reactor high frequency pulse counting device according to claim 1, characterized in that: The switch input channel realizes a configurable diagnostic mode by using the mode of the main control unit, the multiplexer and the solid-state relay; each switch input channel includes a third solid-state relay, a fourth solid-state relay and an optical coupler; The working status of the switch input channel includes: Second acquisition state: when the control signal sent by the main control unit is a switch quantity acquisition signal, the opening of the switch quantity input channel controls the third solid-state relay through the main control unit. When the switch quantity input channel works normally, the third solid-state relay is closed, the fourth solid-state relay is disconnected, and the optocoupler collects the external contact signal; Second diagnostic state: When the control signal sent by the main control unit is a switch quantity diagnostic signal, the third solid-state relay of the switch quantity input channel is disconnected, so that the optocoupler is disconnected from the external dry contact, and the diagnostic state is entered; the fourth solid-state relay for diagnosis is closed and opened by the main control unit. At this time, the main control unit reads back the switch quantity state and compares it with the control signal of the main control unit. If the states are consistent, it means that the switch quantity input channel is normal; If the status is inconsistent, it means that the switch input channel is abnormal.

8. A nuclear reactor high frequency pulse counting device according to claim 1, characterized in that: The 8 pulse quantity input channels are isolated from the reactor external nuclear measurement system, and the pulse quantity input channels are isolated from each other; The 16-way switch input channels are isolated from the reactor's external nuclear measurement system.

9. A nuclear reactor high frequency pulse counting device according to claim 1, characterized in that: The high-frequency pulse signals obtained by the 8-channel pulse input channels are time-stamped inside the main control unit. The time stamps represent the pulse rising edge time and falling edge time respectively, and the time resolution is less than or equal to 10ns.

10. A nuclear reactor high frequency pulse counting device according to claim 1, characterized in that: The high frequency pulse counting device is used in reactor nuclear instrumentation systems, detector arrays, and main pump speed measurement applications.

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