Instrument control system applied to reactor protection of nuclear power plant, and implementation method therefor

Abstract

Disclosed in the present invention are an instrument control system applied to reactor protection of a nuclear power plant, and an implementation method therefor. A lower-level reactor core protection cabinet of the instrument control system comprises four lower-level sub-cabinets, each lower-level sub-cabinet comprising a first control chip, a second control chip and a third control chip, wherein an output end of each first control chip is in communication connection with all second control chips, an output end of each second control chip is in communication connection with all third control chips, and each second control chip is in communication connection with an upper-level reactor core protection cabinet; each first control chip is used for receiving a self-powered neutron detector detection signal issued by a signal processing sub-cabinet; each second control chip is used for calculating a linear power density, a departure from nucleate boiling ratio and a threshold comparison result; and each third control chip is used for issuing a reactor shutdown instruction. Compared with the prior art, the instrument control system of the present invention greatly reduces the total reactor shutdown time, effectively improves the rapidity of a reactor shutdown protection action, and improves the accuracy and stability of reactor shutdown protection.

Description

Instrument control system applied in reactor protection of nuclear power plant and implementation method thereof TECHNICAL FIELD

[0001] The present application relates to the field of nuclear power plant instrument control technology, in particular to an instrument control system applied in reactor protection of nuclear power plant and an implementation method thereof. BACKGROUND

[0002] The core protection is an automatic shutdown system for preventing the development of a reactor severe accident, and the core protection (also known as an advanced reactor protection system ARPS) uses a self-powered neutron detector (SPND) to obtain power (or neutron flux) signals at different positions of the core in real time, and directly calculates the real-time minimum DNBR and local maximum LPD of the core through a series of protection algorithms, which are directly used for core protection.

[0003] Please refer to FIG. 1, the core has a total of 177 fuel assemblies, and the positions of A, B, C and D together contain 42 groups of SPND assemblies. The 42 groups of SPND assemblies are collected through 4 instrument control channels, and the instrument control IP channel corresponds to 11 groups of SPND assemblies at position A, the instrument control IIP channel corresponds to 11 groups of SPND assemblies at position B, the instrument control IIIP channel corresponds to 10 groups of SPND assemblies at position C, and the instrument control IVP channel corresponds to 10 groups of SPND assemblies at position D. Each SPND assembly contains 7 detectors in the axial direction.

[0004] The existing core protection system can be divided into a neutron flux signal processing cabinet (ASPC), a core protection upper computer cabinet (AUPC) and a core protection lower computer cabinet (ALPC) from the function, and the functions of each part are shown in FIG. 2. The neutron flux signal processing cabinet is used for collecting and conditioning the SPND signal (including current signal and state signal), removing invalid signals, and then performing delay compensation on the SPND current signal and state signal through a delay compensation algorithm. The core protection upper computer cabinet is used for realizing core flux map power reconstruction, and providing the core state parameters (hereinafter referred to as correction parameters) required by the protection algorithm for the ALPC at intervals. The core protection lower computer cabinet is used for reconstructing the core power distribution through a power mapping algorithm according to the latest core state parameters and the delay-processed SPND current signal and state signal, and the reconstructed core power is used for real-time calculation of high linear power density (HLPD), low deviation of nuclear boiling ratio (LDNBR) and other values, to realize the online HLPD and LDNBR protection functions.

[0005] The technical scheme of the instrument control system of the existing core protection system is shown in FIG. 3, which includes the following contents:

[0006] Firstly, 42 groups of SPND signals are collected through four ASPC cabinets (i.e. four instrument control channels), the weak signals of the SPND signals are conditioned in the ASPC, and the SPND signals are compensated for delay through a delay compensation algorithm, the compensated signals are converted into 4-20 mA standard signals and transmitted to the ALPC through hardwiring, corresponding to the signal link A / B / C / D in FIG. 3.

[0007] After the four instrument control channels ALPC receive the 4-20 mA standard signals sent by the corresponding channel ASPC, the ALPC transmits the SPND signals received by hardwiring in this channel to the ALPCs of the other three channels through point-to-point communication. In this way, there are 294 (42*7) SPND signals in each ALPC, and complex operations such as power reconstruction, linear power density (LPD) and departure from nucleate boiling ratio (DNBR) are carried out in the ALPC of this channel, and a shutdown instruction is generated according to the calculation results. The ALPC of each instrument control channel generates a shutdown instruction.

[0008] The SPND signals in the ALPC, the final state of the probe, the intermediate calculation process (LPD, DNBR, etc.) and the shutdown instruction are unidirectionally transmitted to the KIC and the core monitoring cabinet through the Safety System Bus (ARPS safety system bus) via the gateway GW.

[0009] The AUPC transmits correction parameters to the ALPC through a network cable on a regular basis. Since the AUPC is a low safety level device and the ALPC is a high safety level device, the network cable between the AUPC and the ALPC is connected only when the correction parameters are transmitted, and the network cable needs to be disconnected after the transmission is completed.

[0010] However, the prior art at least has the following defects:

[0011] 1) The total length of the shutdown time exceeds the standard

[0012] The total length of the time for collecting signals from the reactor (the time for collecting signals from the reactor is T1), processing by the ASPC (the time for processing by the ASPC is T2), transmitting to the ALPC (the time for transmitting is T3), ALPC operation and generating the final shutdown instruction (the time for ALPC operation and generating the final shutdown instruction is T4) should be as short as possible in order to ensure the rapidity of the reactor shutdown protection. In the prior art, the total shutdown time T = T1 + T2 + T3 + T4, wherein T1 + T2 + T3 ≈ 300 ms.

[0013] The algorithm for calculating LPD and DNBR is very complex and has a large amount of calculation, because the operation period of the MPU needs to be as long as possible under the premise of ensuring that the load of the MPU in the ALPC does not exceed the standard. In view of this, the MPU calculation period of the ALPC is usually not less than 200 ms.

[0014] Please refer to Figure 4. Since signal acquisition, core power reconfiguration, threshold comparison, and 2 / 4 logic voting are all performed in the same MPU, T4 = T41 + T42 + T43 = 1.7 * 200ms * 3 = 1020ms. The total downtime T = T1 + T2 + T3 + T4 ≈ 1320ms, which exceeds the expected total downtime.

[0015] 2) Parameter calibration leads to significant uncertainty in the shutdown protection function.

[0016] When performing parameter calibration, the AUPC needs to connect to the sub-lower cabinets of the ALPC one by one. Since the AUPC is a low-security-level device, the corresponding ALPC needs to be bypassed when connecting the AUPC and ALPC.

[0017] The SPND signal collected by the bypassed ALPC sub-cabinet may not be able to be transmitted to the other three ALPC channels via point-to-point communication. This results in a 25% reduction in the number of SPNDs used for core power reconfiguration in the other three channels. For example, if the IP channel sub-cabinet is bypassed, the number of SPNDs used for core power reconfiguration in the other three channels decreases from 294 to 217. This, in turn, leads to a decrease in the accuracy of subsequent LPD and DNBR calculations, i.e., an increase in the uncertainty of shutdown protection, which is detrimental to reactor protection.

[0018] 3) The validity of the calibration parameters cannot be guaranteed.

[0019] Because AUPC has a lower safety level, the correction parameters it generates are used for protection calculations in the higher safety level ALPC. If there is a problem with the generation of correction parameters, the protection calculations in ALPC will also be incorrect, thus failing to effectively trigger the reactor shutdown protection.

[0020] In view of this, it is indeed necessary to provide an instrumentation and control system and its implementation method for use in nuclear power plant reactor protection. Summary of the Invention

[0021] The purpose of this invention is to overcome the problems of excessive total shutdown time and parameter correction leading to increased uncertainty in the protection function of the core protection instrumentation and control system in the prior art, and to provide an instrumentation and control system and its implementation method for use in nuclear power plant reactor protection.

[0022] In order to achieve the above-mentioned object, the application provides a kind of instrument control system applied in nuclear power plant reactor protection, it includes neutron flux signal processing cabinet, reactor protection host cabinet and reactor protection lower computer cabinet.Neutron flux signal processing cabinet includes four sub signal processing cabinets, the sub signal processing cabinet and reactor protection host cabinet are connected with the reactor protection lower computer cabinet by hardwiring and communication respectively, and the reactor protection lower computer cabinet includes 4 sub lower computer cabinets, wherein the sub lower computer cabinet includes a first control chip, a second control chip and a third control chip, the input end of four first control chips is connected with four sub signal processing cabinets one by one, the output end of the first control chip is connected with the input end of all second control chips, the output end of the second control chip is connected with the input end of all third control chips, and the second control chip is connected with the reactor protection host cabinet, the first control chip is used to receive the self-powered neutron detector detection signal sent by the sub signal processing cabinet, the second control chip is used to calculate linear power density, deviation from bubble nucleate boiling ratio and threshold comparison result, and the third control chip is used to send shutdown instruction.

[0023] According to one embodiment of the application, the first control chip is specifically used to receive the self-powered neutron detector detection signal sent by the sub signal processing cabinet and perform format conversion or data rejection processing to obtain processed self-powered neutron detector detection signal, the second control chip is specifically used to obtain the core state parameters obtained by the reactor protection host cabinet and the processed self-powered neutron detector detection signal obtained by the first control chip, and calculate linear power density and deviation from bubble nucleate boiling ratio according to the core state parameters and the processed self-powered neutron detector detection signal, compare the linear power density and the deviation from bubble nucleate boiling ratio with preset threshold to obtain threshold comparison result, and the third control chip is specifically used to obtain the threshold comparison result and perform logic voting according to the threshold comparison result, and send shutdown instruction when the logic combination requirement is met.

[0024] According to one embodiment of the application, the logic voting is four-out-of-two logic voting or three-out-of-two logic voting.

[0025] According to one embodiment of the application, the processed self-powered neutron detector detection signal, the threshold comparison result and the shutdown instruction are all sent to nuclear power plant computer information and control system.

[0026] According to an embodiment of the instrument control system applied in the reactor protection of a nuclear power plant, the first control chip, the second control chip and the third control chip are communicatively connected to a safety system bus, and the safety system bus is connected to a computer information and control system of the nuclear power plant through a gateway of the reactor core protection lower-level cabinet.

[0027] According to an embodiment of the instrument control system applied in the reactor protection of a nuclear power plant, the first control chip and the second control chip are communicatively connected in a point-to-point unidirectional manner.

[0028] According to an embodiment of the instrument control system applied in the reactor protection of a nuclear power plant, the sub-signal processing cabinet is configured to obtain a self-sustaining neutron detector detection signal, and perform conditioning, invalid signal removal, delay compensation and data conversion processing on the self-sustaining neutron detector detection signal to obtain a delay-compensated self-sustaining neutron detector detection signal, and send the delay-compensated self-sustaining neutron detector detection signal to the first control chip.

[0029] According to an embodiment of the instrument control system applied in the reactor protection of a nuclear power plant, the reactor core protection upper-level cabinet includes a reactor core monitoring cabinet and a correction station, the reactor core monitoring cabinet is configured to calculate reactor core state parameters and send the reactor core state parameters to the correction station, the correction station is configured to review the validity of the corrected reactor core state parameters, and the reactor core protection upper-level cabinet is configured to send the corrected reactor core state parameters to each second control chip.

[0030] According to an embodiment of the instrument control system applied in the reactor protection of a nuclear power plant, the correction station is specifically configured to obtain corrected reactor core state parameters from the reactor core monitoring cabinet and self-sustaining neutron detector detection signals from the reactor core protection lower-level cabinet, and calculate linear power density and departure from nucleate boiling ratio based on the corrected reactor core state parameters and the self-sustaining neutron detector detection signals, and review the validity of the reactor core state parameters generated by the reactor core monitoring cabinet, wherein the algorithm for calculating the linear power density and the departure from nucleate boiling ratio by the correction station is the same as the algorithm for calculating the linear power density and the departure from nucleate boiling ratio by the second control chip.

[0031] In a second aspect, the present application provides an implementation method of an instrument control system applied in the reactor protection of a nuclear power plant, wherein the instrument control system is the instrument control system applied in the reactor protection of a nuclear power plant according to the first aspect of the present application, and the method comprises:

[0032] The first control chip receives the self-sustaining neutron detector detection signal sent by the sub-signal processing cabinet and performs format conversion or data rejection processing to obtain a processed self-sustaining neutron detector detection signal.

[0033] The second control chip obtains the core state parameters obtained by the core protection upper cabinet and the processed self-powered neutron detector detection signals obtained by the first control chip, and calculates the linear power density and the departure from nucleate boiling ratio according to the core state parameters and the processed self-powered neutron detector detection signals, compares the linear power density and the departure from nucleate boiling ratio with preset threshold values to obtain threshold comparison results.

[0034] The third control chip obtains the threshold comparison results and makes a logical decision according to the threshold comparison results, and issues a shutdown instruction when a specified logical combination requirement is met.

[0035] According to one embodiment of the implementation method of the instrument control system applied in the reactor protection of a nuclear power plant, before the step of receiving the self-powered neutron detector detection signals sent by the sub-signal processing cabinet and performing format conversion or data rejection processing to obtain the processed self-powered neutron detector detection signals, the method further includes: the sub-signal processing cabinet acquires the self-powered neutron detector detection signals and performs conditioning, invalid signal removal, delay compensation and data conversion processing to obtain the delay-compensated self-powered neutron detector detection signals.

[0036] According to one embodiment of the implementation method of the instrument control system applied in the reactor protection of a nuclear power plant, the core state parameters are corrected core state parameters.

[0037] Compared with the prior art, the present application designs the sub-lower cabinet to include a first control chip, a second control chip and a third control chip, the first control chip is used to receive the self-powered neutron detector detection signals sent by the sub-signal processing cabinet, the second control chip is used to calculate the linear power density, the departure from nucleate boiling ratio and the threshold comparison results, and the third control chip is used to issue a shutdown instruction, so that the total shutdown time is much lower than that of the prior art, the total shutdown time is reduced from about 1.3s to about 725ms, and the rapidity of the shutdown protection action is effectively improved. The second control chip is connected to the core protection upper cabinet, which avoids the bypass of the first control chip, so that the second control chip can definitely obtain a complete number of SPND signals, and thus the calculation accuracy of the second control chip will not be reduced, that is, the determination degree of the shutdown protection is stable, the linear power density and the departure from nucleate boiling ratio protection accuracy are improved, and the accuracy and stability of the shutdown protection are improved. At the same time, the core monitoring cabinet is based on a server architecture, and has low safety level and reliability, and the addition of an independent correction station can effectively review the core state parameters calculated by the core monitoring cabinet, and improve the high reliability of the advanced core protection. BRIEF DESCRIPTION OF DRAWINGS

[0038] The instrument control system applied in the reactor protection of a nuclear power plant and the implementation method thereof will be described in detail below in combination with the drawings and specific embodiments, in which:

[0039] Fig. 1 is a schematic diagram of a fuel assembly and SPND arrangement.

[0040] Fig. 2 is a schematic diagram of a reactor protection function.

[0041] Fig. 3 is a schematic diagram of an implementation scheme of an existing reactor protection I&C system.

[0042] Fig. 4 is a schematic diagram of calculation of time T4.

[0043] Fig. 5 is a schematic diagram of a scheme of an I&C system applied in reactor protection of a nuclear power plant according to the present application.

[0044] Fig. 6 is a flow chart of an implementation method of an I&C system applied in reactor protection of a nuclear power plant according to the present application. DETAILED DESCRIPTION

[0045] In order to make the inventive purpose, technical scheme and technical effects of the present application clearer, the present application is further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described in the present specification are only for the purpose of explaining the present application, and are not intended to limit the present application.

[0046] In advanced reactor protection, the total reactor shutdown time occupied by signal acquisition, reactor power reconstruction, threshold comparison and logic voting is about 1300 milliseconds, and the total shutdown time needs to be reduced. Parameter calibration causes large uncertainty of the protection function: the SPND signal (detection signal of self-powered neutron detector) collected by the bypassed ALPC may not be sent to the other three ALPC channels through point-to-point communication, which will reduce the calculation accuracy of the subsequent LPD and DNBR, and further increase the uncertainty of the shutdown protection, which is not conducive to reactor protection.

[0047] Therefore, the present application provides an I&C system applied in reactor protection of a nuclear power plant and an implementation method thereof, which greatly reduces the total shutdown time length by designing a reactor protection lower computer cabinet, avoids the influence of parameter calibration on the shutdown protection function, and improves the certainty of the shutdown protection function.

[0048] Next, the I&C system applied in reactor protection of a nuclear power plant and the implementation method thereof according to the present application and the technical effects thereof are described.

[0049] Please refer to Fig. 5, which is a schematic diagram of the implementation scheme of the instrument control system applied in the reactor protection of the nuclear power plant according to the present application. The instrument control system comprises a neutron flux signal processing cabinet, a reactor core protection upper computer cabinet and a reactor core protection lower computer cabinet. The neutron flux signal processing cabinet comprises four sub-signal processing cabinets. The sub-signal processing cabinets and the reactor core protection upper computer cabinet are connected to the reactor core protection lower computer cabinet through hardwiring and communication, respectively. The reactor core protection lower computer cabinet comprises four sub-lower computer cabinets. Each sub-lower computer cabinet comprises a first control chip, a second control chip and a third control chip. The input ends of the four first control chips are connected to the four sub-signal processing cabinets one by one. The output end of the first control chip is connected to the input ends of all the second control chips through communication. The output end of the second control chip is connected to the input ends of all the third control chips. The second control chip is connected to the reactor core protection upper computer cabinet through communication. The first control chip is used for receiving the self-powered neutron detector detection signals sent by the sub-signal processing cabinet. The second control chip is used for calculating the linear power density, the off-bubble nucleate boiling ratio and the threshold comparison result. The third control chip is used for sending the shutdown instruction.

[0050] In the embodiment, the output end of the reactor core protection upper computer cabinet is connected to the input end of the reactor core protection lower computer cabinet through communication. Specifically, the communication is offline periodically.

[0051] In the embodiment, the four sub-signal processing cabinets of the neutron flux signal processing cabinet correspond to four channels, i.e., the instrument control IP channel, the instrument control IIP channel, the instrument control IIIP channel and the instrument control IVP channel. The four sub-lower computer cabinets correspond to the four channels one by one.

[0052] In the embodiment, each sub-signal processing cabinet is connected to a self-powered neutron detector. The sub-signal processing cabinet is used for obtaining the self-powered neutron detector detection signal and performing the first processing to obtain the self-powered neutron detector detection signal after delay compensation.

[0053] Specifically, the first processing comprises conditioning, removing invalid signals, delay compensation and data conversion. The sub-signal processing cabinet is used for obtaining the self-powered neutron detector detection signal (SPND signal for short). The sub-signal processing cabinet is used for collecting the SPND signal and conditioning the weak signal in the collected SPND signal. The sub-signal processing cabinet is used for removing the invalid signals in the SPND signal, performing delay compensation on the SPND signal after removing the invalid signals through a delay compensation algorithm, converting the compensated signal into a standard SPND signal after delay compensation, and sending the final result, i.e., the SPND signal after delay compensation after standard conversion.

[0054] In the embodiment, the detection signal includes a current signal, i.e. a current obtained by measuring a current formed by the released electrons with a current meter. Correspondingly, the function of the sub-signal processing cabinet includes modeling the current signal data, filtering the modeled current signal, and determining whether a single-point failure exists by using a delay compensation algorithm.

[0055] The sub-signal processing cabinet is also used to send a standard converted delay compensated SPND signal. In the embodiment, the sub-signal processing cabinet and the first control unit are connected by hardwiring, and the standard SPND signal is transmitted to the corresponding first control chip in the core protection lower cabinet by hardwiring.

[0056] It can be understood that the calculation and processing of the four sub-lower cabinets are independent of each other, and there is transmission of information, but the processing process and calculation process of data are independent of each other.

[0057] It can be understood that the first control chip, the second control chip and the third control chip of each sub-lower cabinet are independent of each other, and the first control chip, the second control chip and the third control chip are not executed in a single independent MPU. It can be understood that the sub-lower cabinet adopts a three-layer architecture, and the first control chip, the second control chip and the third control chip correspond to the first layer control unit L1, the second layer control unit L2 and the third layer control unit L3 respectively.

[0058] It can be understood that the communication connection between the first control chip and the second control chip is a point-to-point one-way communication connection.

[0059] The first control chip, the second control chip and the third control chip are all signal connected to a safety level system bus, which specifically adopts an ARPS Safety System Bus and is specifically a multi-point communication connection mode. The core protection lower cabinet further includes a gateway, and the ARPS Safety System Bus connects the KIC system and the core protection upper cabinet (core monitoring cabinet) through the gateway GW.

[0060] The first control chip is used to receive the self-powered neutron detector detection signal (i.e. the delay compensated SPND signal) sent by the sub-signal processing cabinet, and to perform a second processing to obtain a processed self-powered neutron detector detection signal. As an example but not limitation, the second processing includes format conversion. As another example but not limitation, the second processing includes data rejection, i.e. filtering data, specifically analyzing fault data in the standard SPND signal and rejecting the fault data.

[0061] Further, the first control chip is configured to send the processed SPND signal to all second control chips through point-to-point communication in one direction; and the first control chip is further configured to transmit the processed SPND signal to a KIC system (nuclear power plant computer information and control system) and a core monitoring cabinet through an ARPS Safety System Bus in one direction.

[0062] Since the first control chip performs a small amount of calculation, the calculation period of the first control chip is as short as possible, and 25 ms is adopted.

[0063] The second control chip is configured to obtain a core state parameter obtained by a core protection upper cabinet and a processed self-powered neutron detector signal obtained by the first control chip, and calculate a linear power density and a departure from nucleate boiling ratio according to the core state parameter and the processed self-powered neutron detector signal, and compare the linear power density and the departure from nucleate boiling ratio with preset thresholds to obtain a threshold comparison result. The core protection upper cabinet is configured to generate the core state parameter, and the core protection upper cabinet can be connected to the second control chip in one-way communication. Specifically, the second control chip is configured to receive the processed SPND signal of all first control chips, calculate the LPD and the DNBR according to the processed SPND signal and the core state parameter, compare the LPD with a preset first threshold and compare the DNBR with a preset second threshold to obtain a comparison result, and transmit the threshold comparison result to all third control units through communication in one direction.

[0064] Further, the core state parameter obtained by the second control chip is a corrected core state parameter (see below for details), and the corrected core state parameter is a core state parameter that has been confirmed to be correct. The second control chip reconstructs the power distribution of the core according to the corrected core state parameter and the processed self-powered neutron detector signal through a power mapping algorithm, and the reconstructed core power is used to calculate the HLPD and the LDNBR in real time, thereby realizing the online HLPD and LDNBR protection functions.

[0065] The second control chip is further configured to transmit the threshold comparison result to the KIC system through the ARPS Safety System Bus in one direction.

[0066] Since the LPD and the DNBR have a large amount of calculation, the calculation period of the second control unit is not less than 200 ms.

[0067] The third control chip is used to obtain the threshold comparison results and make a logical decision according to the threshold comparison results, and is used to send a trip command when a specified logical combination requirement is met. Specifically, the third control unit receives the threshold comparison results of all the second control units through communication, and makes a signal for logical decision through processing such as calculation and value comparison, and then makes a logical decision through a two-out-of-four or a two-out-of-three composite logical operation, and sends a trip command when a specified logical combination requirement is met. The third control chip is also used to send the trip command unidirectionally to the KIC system through the ARPS Safety System Bus.

[0068] Since the third control unit has a small amount of calculation, the third control unit calculation period is as short as possible, and 25 ms is adopted.

[0069] In another embodiment, a communication module connected to the AUPC is arranged in the ALPC, and is used to receive the core state parameters and send the core state parameters to the second control chip. Specifically, the AUPC transmits the parameters offline to the communication module, and when the ALPC is working, the communication module sends the core state parameters to the corresponding second control chip.

[0070] Since the validity of the correction parameters cannot be guaranteed in the prior art, that is, since the core monitoring cabinet adopts a server architecture and has a low safety level, the correction parameters generated by the core monitoring cabinet are used for protection operation in the high-safety-level ALPC, and if the generation of the correction parameters is problematic, the protection operation in the ALPC will also be erroneous.

[0071] In the embodiment, the core protection upper cabinet includes a core monitoring cabinet and a correction station. The core monitoring cabinet is connected to the correction station. The core monitoring cabinet is used to generate core state parameters and send the core state parameters to the correction station, and the core monitoring cabinet sends the core state parameters to the correction station through a first link E. The correction station calculates the LPD and the DNBR by using the latest core state parameters, and is used to review the validity of the core state parameters. The correction station or the core monitoring cabinet sends the corrected core state parameters to the second control chip. In the embodiment, the core monitoring cabinet is used to implement core flux map power reconstruction, and is used to periodically send the corrected core state parameters to the second control chip through a network cable at a certain time interval. Since the core monitoring cabinet is a low-safety-level device and the ALPC is a high-safety-level device, only the network cable from the AUPC to the ALPC is connected when the corrected parameters are transmitted, and the network cable needs to be disconnected after the transmission is completed.

[0072] In the embodiment, the algorithm for calculating the LPD and the DNBR in the correction station is the same as the algorithm for calculating the LPD and the DNBR in the ALPC.

[0073] Compared with the prior art, the independent correction station is added in the AUPC through the embodiment, the correction station obtains the SPND signal from the ALPC through the second link F, specifically, the correction station obtains the SPND signal processed by the first control chip and obtains the threshold comparison result of the second control chip; when the correction parameter is generated by the core monitoring cabinet, the correction parameter is first sent to the correction station through the first link E, the correction station calculates the LPD and DNBR by using the latest correction parameter, and the correction parameter is confirmed to be correct, and the correction parameter is transmitted to the ALPC for formal protection calculation only after the correction parameter is confirmed to be correct.

[0074] Therefore, the independent correction station is added in the AUPC. The correction station obtains the SPND signal through the link F, and adopts the protection algorithm which is completely consistent with that in the ALPC; when the correction parameter is generated by the core monitoring cabinet through calculation, the correction parameter is first sent to the correction station through the link E, the correction station calculates the LPD and DNBR by using the new correction parameter, and the correction parameter is transmitted to the ALPC for formal protection calculation only after the correction parameter is confirmed to be correct, thereby improving the effectiveness of the correction parameter and avoiding the problem of the core state parameter generated by the core protection upper cabinet from affecting the calculation of the core protection lower cabinet.

[0075] Please refer to Fig. 6, which shows the implementation method of the instrument control system applied in the reactor protection of the nuclear power plant, which comprises the following steps:

[0076] The first control chip receives the self-powered neutron detector detection signal sent by the sub-signal processing cabinet and performs the second processing to obtain the processed self-powered neutron detector detection signal;

[0077] The second control chip obtains the core state parameter obtained by the core protection upper cabinet and the processed self-powered neutron detector detection signal obtained by the first control chip, and calculates the linear power density and the deviation from the nucleate boiling ratio according to the core state parameter and the processed self-powered neutron detector detection signal, and compares the linear power density and the deviation from the nucleate boiling ratio with the preset threshold value to obtain the threshold comparison result;

[0078] The third control chip obtains the threshold comparison result and performs the logic voting according to the threshold comparison result, and sends the shutdown instruction when the specified logic combination requirement is met.

[0079] Further, before the above steps, the method further comprises the step that the sub-signal processing cabinet obtains the self-powered neutron detector detection signal and performs the first processing to obtain the time delay compensated self-powered neutron detector detection signal.

[0080] Further, the core state parameter is the corrected core state parameter.

[0081] Further, the implementation method of the instrument control system applied in the reactor protection of the nuclear power plant further comprises the following steps:

[0082] The core monitoring cabinet obtains the core state parameters by calculation and sends to the correction station;

[0083] The correction station obtains the core state parameters;

[0084] The correction station obtains the self-powered neutron detector detection signal from the core protection lower cabinet;

[0085] The correction station reviews the validity of the core state parameters;

[0086] The core protection upper cabinet sends the core state parameters after correction to the second control chip.

[0087] Compared with the prior art, the instrument control system applied in the reactor protection of the nuclear power plant and the implementation method have the following effects:

[0088] (1) The total shutdown time length is reduced;

[0089] In the application, T4=T41+T42+T43=1.7*25ms+1.7*200ms+1.7*25ms=425ms, and the total shutdown time T=T1+T2+T3+T4≈725ms, which is far lower than that of the prior art, and the total shutdown time is reduced from about 1.3s to about 725ms, so that the rapidity of the shutdown protection action can be effectively improved.

[0090] (2) The parameter correction does not affect the shutdown protection function, and the certainty of the shutdown protection function is improved;

[0091] Since the instrument control implementation adopts a three-layer architecture, the AUPC is only connected to the second control chip of the ALPC to realize parameter correction, so the first control chip can not be bypassed, and the first control chip can be sent to other channels of the ALPC through point-to-point communication, so that each channel of the ALPC can still collect complete 294 SPND signals, so that the subsequent LPD and DNBR calculation accuracy will not be reduced, that is, the certainty of the shutdown protection is stable, and the LPD and DNBR protection accuracy is improved; but the voting logic of the third control chip in other channels may be degraded from 2 / 4 to 2 / 3.

[0092] (3) An independent correction station is arranged to improve the validity of the core state parameters;

[0093] The results of the core monitoring cabinet are corrected by the correction station, so that errors in the core state parameters are avoided, and the protection operation in the ALPC is also correspondingly incorrect, so that the shutdown protection cannot be effectively triggered.

[0094] By adding independent correction station in AUPC, the corrected core state parameters are transmitted to ALPC for protection calculation after the confirmed core state parameters are calculated.

[0095] The application is applied to the instrument control system in nuclear power plant reactor protection and the implementation method thereof, which not only effectively improves the rapidity of shutdown protection action and the certainty of shutdown protection function, but also improves the effectiveness of core state parameters, and further improves the accuracy of nuclear power plant reactor protection.

[0096] According to the above principles, the above embodiments can also be appropriately changed and modified. Therefore, the application is not limited to the specific embodiments disclosed and described above, and some modifications and changes of the application should fall within the protection scope of the claims of the application. In addition, although some specific terms are used in the specification, these terms are only for convenience of description and do not constitute any limitation on the application.

Claims

1. An I&C system applied in reactor protection of a nuclear power plant, comprising a neutron flux signal processing cabinet, a core protection upper cabinet and a core protection lower cabinet, the neutron flux signal processing cabinet comprising four sub signal processing cabinets, the sub signal processing cabinets and the core protection upper cabinet being connected to the core protection lower cabinet through hardwiring and communication respectively, the core protection lower cabinet comprising four sub lower cabinets, characterized in that, Each of the sub-core protection lower cabinets comprises a first control chip, a second control chip and a third control chip, the input ends of the four first control chips are connected one by one with the four sub-signal processing cabinets, the output end of the first control chip is communicatively connected with the input ends of all the second control chips, the output end of the second control chip is communicatively connected with the input ends of all the third control chips, the second control chip is communicatively connected with the core protection upper cabinet, the first control chip is used for receiving the self-sufficient neutron detector detection signals sent by the sub-signal processing cabinet, the second control chip is used for calculating the linear power density, the deviation from the bubble nucleate boiling ratio and the threshold comparison result, and the third control chip is used for sending the shutdown instruction.

2. The I&C system for use in the protection of a nuclear power plant reactor according to claim 1, characterized in that, The first control chip is specifically used for receiving the self-sufficient neutron detector detection signals sent by the sub-signal processing cabinet and performing format conversion or data rejection processing to obtain processed self-sufficient neutron detector detection signals, the second control chip is specifically used for obtaining the core state parameters obtained by the core protection upper cabinet and the processed self-sufficient neutron detector detection signals obtained by the first control chip, and calculating the linear power density and the deviation from the bubble nucleate boiling ratio according to the core state parameters and the processed self-sufficient neutron detector detection signals, and obtaining the threshold comparison result by comparing the linear power density and the deviation from the bubble nucleate boiling ratio with a preset threshold, and the third control chip is specifically used for obtaining the threshold comparison result and performing logical voting according to the threshold comparison result, and sending the shutdown instruction when a specified logical combination requirement is met.

3. The I&C system for use in the protection of a nuclear power plant reactor according to claim 2, characterized in that, The logical voting is a four-out-of-two logical voting or a three-out-of-two logical voting.

4. The I&C system for use in the protection of a nuclear power plant reactor according to claim 2, characterized in that, The processed self-sufficient neutron detector detection signals, the threshold comparison result and the shutdown instruction are all sent to a nuclear power plant computer information and control system.

5. An I&C system for use in the protection of a nuclear power plant reactor according to claim 4, characterized in that, The first control chip, the second control chip and the third control chip are communicatively connected with a safety system bus, and the safety system bus connects the nuclear power plant computer information and control system through a gateway of the core protection lower cabinet.

6. The I&C system for use in the protection of a nuclear power plant reactor as claimed in claim 1, characterized in that, The communication connection between the first control chip and the second control chip is a point-to-point one-way communication connection.

7. The I&C system applied in the protection of the reactor of a nuclear power plant according to claim 1, characterized in that, The sub-signal processing cabinet is used for obtaining self-sufficient neutron detector detection signals and performing conditioning, removing invalid signals, delay compensation and data conversion processing to obtain delay-compensated self-sufficient neutron detector detection signals, and sending the delay-compensated self-sufficient neutron detector detection signals to the first control chip.

8. The I&C system for use in the protection of a nuclear power plant reactor as defined in claim 1, characterized in that, The core protection upper cabinet comprises a core monitoring cabinet and a correction station, the core monitoring cabinet is used for calculating core state parameters and sending the core state parameters to the correction station, the correction station is used for reviewing the validity of the calculated corrected core state parameters, and the core protection upper cabinet is used for sending the corrected core state parameters to each of the second control chips.

9. The I&C system for use in the protection of a nuclear power plant reactor according to claim 8, characterized in that, The correction station is specifically used for obtaining the core state parameters in the corrected state of the core monitoring cabinet and the detection signals of the self-powered neutron detector from the core protection lower cabinet, and calculating the linear power density and the departure from nucleate boiling ratio according to the core state parameters, which is used for reviewing the effectiveness of the core state parameters generated by the core monitoring cabinet.

10. A method of implementing an I&C system for use in the protection of a nuclear power plant reactor, characterized in that, The instrument control system adopts the instrument control system applied in the reactor protection of the nuclear power plant in any one of claims 1 to 9, and the method comprises: The first control chip receives the detection signals of the self-powered neutron detector from the sub-signal processing cabinet and performs format conversion or data rejection processing to obtain processed detection signals of the self-powered neutron detector; The second control chip obtains the core state parameters obtained by the core protection upper cabinet and the processed detection signals of the self-powered neutron detector obtained by the first control chip, and calculates the linear power density and the departure from nucleate boiling ratio according to the core state parameters, compares the linear power density and the departure from nucleate boiling ratio with a preset threshold value to obtain a threshold comparison result; The third control chip obtains the threshold comparison result and performs logic voting according to the threshold comparison result, and issues a shutdown instruction when a specified logic combination requirement is met.

11. The method of claim 10, wherein the method is implemented in an I&C system used in reactor protection of a nuclear power plant. Before the step of receiving the detection signals of the self-powered neutron detector from the sub-signal processing cabinet by the first control chip and performing format conversion or data rejection processing to obtain processed detection signals of the self-powered neutron detector, further comprising: the sub-signal processing cabinet obtains the detection signals of the self-powered neutron detector and performs conditioning, invalid signal removal, delay compensation and data conversion processing to obtain delay-compensated detection signals of the self-powered neutron detector.

12. The method of claim 10, wherein the method is implemented in an I&C system used in reactor protection of a nuclear power plant. The core state parameters are core state parameters in a corrected state.

Images