Method, system, and medium for monitoring cooling channel blockage based on neutron noise signals

Abstract

The application discloses a cooling flow passage blockage monitoring method and system based on a neutron noise signal, and a medium, relates to the technical field of cooling flow passage monitoring, and comprises the following steps: arranging a plurality of self-powered neutron detectors in a reactor, collecting neutron noise signal data measured by the self-powered neutron detectors, establishing a coolant flow distribution relationship based on the neutron noise signal data, obtaining a reactor core coolant flow distribution graph, and determining whether cooling flow passage blockage occurs according to the reactor core coolant flow distribution graph. The application solves the problem that the reactor core flow passage blockage anomaly cannot be monitored, avoids the local overheating of fuel assemblies caused by flow passage blockage, and effectively guarantees the safety and reliability of the reactor core.

Description

Technical Field

[0001] The present invention relates to the technical field of cooling flow channel monitoring, and in particular to a cooling flow channel blockage monitoring method, system and medium based on neutron noise signals. Background Art

[0002] The reactor lower grid plate is an important part of the nuclear power plant's internal components and an important channel for the flow of coolant in the nuclear power plant core. During the operation of the reactor, coolant scaling and foreign matter often cause blockage of the lower grid plate flow channel, resulting in local overheating. In severe cases, it can cause local boiling of the reactor core, impacting the reactor fuel assemblies and control rods, and threatening the safety of the reactor core.

[0003] Since the fuel assembly is located inside the reactor, the surrounding radioactive activity is high and the space is small, it is impossible to arrange vibration detectors inside the reactor to detect abnormal conditions of flow channel blockage. At the same time, the introduction of new detectors may further affect the flow distribution of the flow channel, introducing potential risks to core safety.

[0004] As an important means of measuring core power and thermal-hydraulic parameters, the self-powered detector acquires neutron noise signals (i.e., neutron flux fluctuation signals) that are sensitive not only to thermal-hydraulic phenomena (standing acoustic waves, coolant boiling, and the transport of temperature fluctuations at the coolant speed from the reactor inlet), but also to mechanical vibration phenomena (vibration of the pressure vessel, core basket, and fuel assembly). It can effectively analyze the flow in the core flow channel and locate the channel of abnormal flow, laying the foundation for subsequent core maintenance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: since the fuel assembly is located in the reactor, the surrounding radioactive activity is high and the space is small, it is difficult to arrange vibration detectors in the reactor to detect the abnormal state of flow channel blockage. If a new detector is introduced, it may further affect the flow distribution of the flow channel, introducing potential risks to the safety of the core; the purpose of the present invention is to provide a cooling flow channel blockage monitoring method, system and medium based on neutron noise signals, by arranging multiple self-powered neutron detectors in the reactor, collecting neutron noise signal data measured by each powered neutron detector; and establishing a coolant flow distribution relationship based on the neutron noise signal data to obtain a core coolant flow distribution map; judging whether cooling flow channel blockage occurs according to the core coolant flow distribution map; solving the problem that the abnormal flow channel blockage in the reactor cannot be monitored, avoiding local overheating of the fuel assembly caused by flow channel blockage, and effectively ensuring the safety and reliability of the reactor core.

[0006] The present invention is achieved through the following technical solutions:

[0007] This solution provides a cooling channel blockage monitoring method based on neutron noise signals, including:

[0008] Multiple self-powered neutron detectors are deployed in the reactor to collect neutron noise signal data measured by the self-powered neutron detectors;

[0009] Preprocessing the neutron noise signal data;

[0010] Calculating the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship, and establishing a core coolant flow distribution map based on the coolant flow distribution relationship;

[0011] Determine whether the cooling channel is blocked based on the core coolant flow distribution diagram.

[0012] Working principle of this scheme: Since the fuel assembly is located inside the reactor, the surrounding radioactive activity is high and the space is small, it is difficult to arrange vibration detectors inside the reactor to detect abnormal conditions of flow channel blockage. If new detectors are introduced, it may further affect the flow distribution of the flow channel, introducing potential risks to the safety of the core. The purpose of the present invention is to provide a cooling flow channel blockage monitoring method, system and medium based on neutron noise signals, and to improve the method on the basis of traditional cooling flow channel blockage monitoring technology. This scheme arranges multiple self-powered neutron detectors in the reactor to collect neutron noise signal data measured by each powered neutron detector; and establishes a coolant flow distribution relationship based on the neutron noise signal data to obtain a core coolant flow distribution map; determines whether cooling flow channel blockage occurs according to the core coolant flow distribution map; solves the problem that abnormal flow channel blockage in the reactor cannot be monitored, avoids local overheating of fuel assemblies caused by flow channel blockage, and effectively ensures the safety and reliability of the reactor core.

[0013] Traditional methods for determining abnormal conditions in reactor cooling channel blockage primarily rely on collecting channel temperature data and analyzing it to identify channel anomalies. However, since temperature sensors not only collect channel temperature but also overlay data from other operating equipment near the channel, this analysis of channel anomalies based on temperature data presents certain accuracy issues. Furthermore, in actual operation, the complex curvature of the channel structure makes it difficult to evenly position temperature sensors, resulting in certain accuracy issues. This solution employs multiple self-powered neutron detectors within the reactor to collect neutron noise signal data from each detector. Based on this neutron noise signal data, a coolant flow distribution relationship is established to generate a core coolant flow distribution map. This map is then used to determine whether cooling channel blockage has occurred, addressing the issue of in-core channel blockage anomalies. Traditional methods for determining local channel blockage based on temperature utilize temperature probes placed within the core. When channel blockage occurs, the local temperature rises, and this method can only provide qualitative observations when the blockage is severe. Compared with traditional temperature determination, the method proposed in the present invention can directly calculate the local flow velocity and directly obtain the core flow quantitatively. It can capture information in time when early flow channel blockage occurs, providing guidance for subsequent maintenance.

[0014] A further optimized solution is that the multiple self-powered neutron detectors are arranged in the reactor, including the following method:

[0015] The first control rod assembly and the second control rod assembly are determined according to condition a; condition a: there is no control rod assembly around the first control rod assembly or the first control rod assembly is the second control rod assembly;

[0016] A neutron measurement channel is arranged at the center of the first control rod assembly along the control rod insertion direction, and a plurality of self-powered neutron detectors are arranged at equal depth intervals in each neutron measurement channel.

[0017] A further optimization solution is that the neutron noise signal data includes neutron current signal noise data;

[0018] The neutron noise signal data δφ(r,t) is:

[0019] δφ(r,t)=cδi(r,t)=c[i(r,t)-E(i(r,t))]

[0020] where δi(r,t) represents the neutron current signal noise data; E(·) represents the time-scale mean of the signal; i(r,t) represents the neutron current signal, r represents the position of the core, and t represents time; c represents the linear conversion coefficient of the self-powered neutron detector.

[0021] A further optimization scheme is that the neutron noise signal data is preprocessed, including the following method:

[0022] separating an AC signal and a DC signal from the neutron noise signal data, and amplifying the AC signal;

[0023] sampling the DC signal and the amplified AC signal respectively, and filtering the amplified AC signal to obtain a first AC signal;

[0024] The first AC signal is divided by the DC signal.

[0025] A further optimization scheme is that the flow rate of the reactor coolant is calculated based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship; including the following method:

[0026] Acquiring neutron noise signal data of each energized neutron detector;

[0027] Perform cross-correlation calculation between self-powered neutron detectors at different depths in the same neutron measurement channel;

[0028] The trough structure is identified based on the cross-correlation calculation result, and the coolant flow rate corresponding to the current neutron measurement channel is calculated based on the trough structure identification result.

[0029] A further optimization scheme is to perform cross-correlation calculation between self-powered neutron detectors at different depths in the same neutron measurement channel, including the following method:

[0030] The cross-correlation function between the self-powered neutron detector i and the self-powered neutron detector j is calculated according to the following formula. If a measurement channel has 7 self-powered detectors, the cross-correlation function between the self-powered neutron detector i and the self-powered neutron detector j is calculated as follows: A cross-correlation function;

[0031]

[0032] Where S ii (r,ω) represents the power spectrum density of the self-powered neutron detector i; S jj (r,ω) represents the power spectrum density of the self-powered neutron detector j; S ij (r, ω) represents the cross-power spectral density of self-powered neutron detectors i and j; where i, j (i, j = 1, 2, 3, 4, 5, 6, 7, …, n); n is the total number of self-powered neutron detectors belonging to the same neutron measurement channel; r represents the position of the self-powered neutron detector, and ω represents the circular frequency of the neutron noise signal.

[0033] A further optimization scheme is to perform trough structure identification based on the cross-correlation calculation results, and calculate the coolant flow rate corresponding to the current neutron measurement channel based on the trough structure identification results, including the following method:

[0034] Based on the cross-correlation function between self-powered neutron detector i and self-powered neutron detector j, R is calculated. ij The frequency difference Δf between the two trough structures in (r,ω) ij , if the cross-correlation function has only one trough, take the frequency corresponding to the first trough and multiply the frequency value by 2;

[0035] Calculate the coolant flow rate v corresponding to the current neutron measurement channel according to the following formula:

[0036]

[0037] Among them, τ ij It represents the delay time of power fluctuation under the traction of coolant flow between the trough structure corresponding to self-powered neutron detector i and the trough structure corresponding to self-powered neutron detector j. represents the frequency difference between the trough structure corresponding to the self-powered neutron detector i and the trough structure corresponding to the self-powered neutron detector j; d ij represents the distance between self-powered neutron detector i and self-powered neutron detector j;

[0038] d ij =|z i -z j |

[0039] z i represents the height of the self-powered neutron detector i; z j represents the height of the self-powered neutron detector j.

[0040] A further optimization scheme is that the core coolant flow distribution diagram is established according to the coolant flow distribution relationship, including the following method:

[0041] Calculate the coolant flow rate corresponding to each neutron measurement channel;

[0042] The core flow rate is calculated based on the coolant flow rate corresponding to each neutron measurement channel and the spline curve, and the core coolant flow distribution diagram is drawn.

[0043] This solution also provides a cooling channel blockage monitoring system based on neutron noise signals, which is used to implement the above-mentioned cooling channel blockage monitoring method based on neutron noise signals. The system includes:

[0044] An acquisition module is used to deploy multiple self-powered neutron detectors in the reactor and collect neutron noise signal data measured by each of the self-powered neutron detectors;

[0045] A preprocessing module, used for preprocessing the neutron noise signal data;

[0046] a calculation module for calculating the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship, and establishing a core coolant flow distribution map based on the coolant flow distribution relationship;

[0047] The output module is used to determine whether the cooling channel is blocked based on the core coolant flow distribution diagram.

[0048] The present solution also provides a computer-readable medium having a computer program stored thereon. The computer program is executed by a processor to implement the cooling flow channel blockage monitoring method based on neutron noise signals as described above.

[0049] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0050] The cooling channel blockage monitoring method, system and medium based on neutron noise signals provided by the present invention are methodological improvements based on traditional cooling channel blockage monitoring technology. This scheme arranges multiple self-powered neutron detectors in the reactor to collect neutron noise signal data measured by each powered neutron detector; and establishes a coolant flow distribution relationship based on the neutron noise signal data to obtain a core coolant flow distribution diagram; determines whether cooling channel blockage occurs according to the core coolant flow distribution diagram; solves the problem that abnormal flow channel blockage in the reactor cannot be monitored, avoids local overheating of fuel assemblies caused by flow channel blockage, and effectively ensures the safety and reliability of the reactor core. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0052] Figure 1 Schematic diagram of the flow chart of the cooling channel blockage monitoring method based on neutron noise signals;

[0053] Figure 2 The schematic diagram of the cooling channel blockage monitoring system based on neutron noise signals is shown in FIG.

[0054] Figure 3 Schematic diagram of the cross-correlation function results of Example 4. DETAILED DESCRIPTION

[0055] 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 examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0056] Because the fuel assembly is located inside the reactor, the surrounding radioactivity is high, and the space is limited, it is difficult to arrange vibration detectors inside the reactor to detect abnormal conditions such as flow channel blockage. If new detectors are introduced, the flow distribution of the flow channel may be further affected, introducing potential risks to the safety of the core. In view of this, the present invention provides the following embodiments to solve the above technical problems:

[0057] Example 1

[0058] This embodiment provides a cooling channel blockage monitoring method based on neutron noise signals, such as Figure 1 As shown, including:

[0059] Step 1: deploying multiple self-powered neutron detectors in the reactor and collecting neutron noise signal data measured by each powered neutron detector;

[0060] The method of deploying multiple self-powered neutron detectors in a reactor includes:

[0061] The first control rod assembly and the second control rod assembly are determined according to condition a; condition a: there is no control rod assembly around the first control rod assembly or the first control rod assembly is the second control rod assembly;

[0062] A neutron measurement channel is arranged at the center of the first control rod assembly along the control rod insertion direction, and a plurality of self-powered neutron detectors are arranged at equal depth intervals in each neutron measurement channel.

[0063] The collected neutron noise signal data includes neutron current signal noise data;

[0064] The neutron noise signal data δφ(r,t) is:

[0065] δφ(r,t)=cδi(r,t)=c[i(r,t)-E(i(r,t))]

[0066] where δi(r,t) represents the neutron current signal noise data; E(·) represents the time-scale mean of the signal; i(r,t) represents the neutron current signal, r represents the position of the core, and t represents time; c represents the linear conversion coefficient of the self-powered neutron detector.

[0067] Step 2: preprocessing the neutron noise signal data; specifically including the following method:

[0068] separating an AC signal and a DC signal from the neutron noise signal data, and amplifying the AC signal;

[0069] sampling the DC signal and the amplified AC signal respectively, and filtering the amplified AC signal to obtain a first AC signal;

[0070] The first AC signal is divided by the DC signal.

[0071] Step 3: Calculate the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship, and establish a core coolant flow distribution map based on the coolant flow distribution relationship;

[0072] The method of calculating the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship includes:

[0073] Acquiring neutron noise signal data of each energized neutron detector;

[0074] The cross-correlation calculation is performed between the self-powered neutron detectors at different depths in the same neutron measurement channel; the cross-correlation function between the self-powered neutron detector i and the self-powered neutron detector j is calculated according to the following formula. If a measurement channel has 7 self-powered detectors, the cross-correlation function is calculated as follows: A cross-correlation function;

[0075]

[0076] Where S ii (r,ω) represents the power spectrum density of the self-powered neutron detector i; S jj (r,ω) represents the power spectrum density of the self-powered neutron detector j; S ij (r, ω) represents the cross-power spectral density of self-powered neutron detectors i and j; where i, j (i, j = 1, 2, 3, 4, 5, 6, 7, …, n); i ≠ j; n is the total number of self-powered neutron detectors belonging to the same neutron measurement channel; r represents the position of the self-powered neutron detector, and ω represents the circular frequency of the neutron noise signal.

[0077] The trough structure is identified based on the cross-correlation calculation result, and the coolant flow rate corresponding to the current neutron measurement channel is calculated based on the trough structure identification result; the specific method includes:

[0078] Based on the cross-correlation function between the self-powered neutron detector i and the self-powered neutron detector j, the frequency difference Δf between the two trough structures is calculated. ij ; R ij The frequency difference Δf between the two trough structures in (r,ω) ij ; For example, Figure 3 The neutron detector cross-correlation function with an interval of 1, Δf ij≈6.3Hz*2, the neutron detector cross-correlation function with an interval of 2, Δf ij ≈3.1Hz*2, neutron detector cross-correlation function with interval of 3, Δf ij ≈6.3-2.2=4.1Hz, the cross-correlation function of the neutron detector with an interval of 4, Δf ij ≈4.8-1.8=3Hz, the cross-correlation function of the neutron detector with an interval of 5, Δf ij ≈3.8-1.4=2.4Hz, the cross-correlation function of the neutron detector with an interval of 6, Δf ij ≈3.2-1.2=2Hz.

[0079] Calculate the coolant flow rate v corresponding to the current neutron measurement channel according to the following formula:

[0080]

[0081] Among them, τ ij It represents the delay time of power fluctuation under the traction of coolant flow between the trough structure corresponding to self-powered neutron detector i and the trough structure corresponding to self-powered neutron detector j. represents the frequency difference between the trough structure corresponding to the self-powered neutron detector i and the trough structure corresponding to the self-powered neutron detector j; d ij represents the distance between self-powered neutron detector i and self-powered neutron detector j;

[0082] d ij =|z i -z j |

[0083] z i represents the height of the self-powered neutron detector i; z j represents the height of the self-powered neutron detector j.

[0084] The method of establishing a core coolant flow distribution diagram according to the coolant flow distribution relationship includes:

[0085] Calculate the coolant flow rate corresponding to each neutron measurement channel;

[0086] The core flow rate is calculated based on the coolant flow rate corresponding to each neutron measurement channel and the spline curve, and the core coolant flow distribution diagram is drawn.

[0087] Step 4: Determine whether the cooling channel is blocked based on the core coolant flow distribution diagram; specifically, the method includes:

[0088] A blocking flow threshold is set in advance, and each coolant flow rate in the core coolant flow distribution diagram is compared with the blocking flow threshold. If the coolant flow at the current position exceeds the blocking flow threshold, the flow channel at the current position is determined to be blocked; otherwise, the flow channel at the current position is determined to be normal. Finally, the normal flow channel and the blocked flow channel are distinguished and displayed in the core coolant flow distribution diagram.

[0089] The traditional method for judging the abnormal state of reactor cooling flow channel blockage mainly collects the temperature data of the flow channel and analyzes the temperature data to judge the abnormality of the flow channel. However, on the one hand, in addition to collecting the temperature of the flow channel, the temperature sensor also superimposes the data of other operating equipment near the flow channel, resulting in certain accuracy problems in analyzing the abnormality of the flow channel based on temperature data. On the other hand, during actual operation, due to the complex and curved structure of the flow channel, the points of the temperature sensor are difficult to be evenly distributed, resulting in certain accuracy problems in analyzing the abnormality of the flow channel based on temperature data. This solution arranges multiple self-powered neutron detectors in the reactor to collect neutron noise signal data measured by each self-powered neutron detector; and establishes a coolant flow distribution relationship based on the neutron noise signal data to obtain a core coolant flow distribution map; determines whether the cooling flow channel is blocked according to the core coolant flow distribution map; solves the problem of the inability to monitor the abnormality of the flow channel blockage in the reactor; the traditional method of judging local flow channel blockage based on temperature is to use temperature probes arranged in the core. When the flow channel is blocked in the core, the local temperature rises. This method can only perform qualitative observations when the flow channel blockage is more serious. Compared with traditional temperature determination, the method proposed in the present invention can directly calculate the local flow velocity and directly obtain the core flow quantitatively. It can capture information in time when early flow channel blockage occurs, providing guidance for subsequent maintenance.

[0090] Example 2

[0091] This embodiment provides a cooling channel blockage monitoring system based on neutron noise signals, which is used to implement the cooling channel blockage monitoring method based on neutron noise signals described in Example 1. Figure 2 As shown, the system includes:

[0092] An acquisition module is configured to acquire neutron noise signal data measured by self-powered neutron detectors. Specifically, the acquisition module includes a plurality of self-powered neutron detectors disposed within the reactor. A first control rod assembly and a second control rod assembly are determined according to condition a; condition a: the first control rod assembly is surrounded by no control rod assemblies or is surrounded by the second control rod assembly. A neutron measurement channel is disposed at the center of the first control rod assembly along the direction of control rod insertion, and a plurality of self-powered neutron detectors are disposed at equal depth intervals within each neutron measurement channel.

[0093] A preprocessing module, used for preprocessing the neutron noise signal data;

[0094] The preprocessing module includes an amplifier circuit, a filter circuit, and a DC isolation circuit. The DC isolation circuit separates the AC signal and DC signal of the neutron noise signal data. The amplifier circuit is used to amplify the AC signal, and the filter circuit is used to filter the amplified AC signal.

[0095] a calculation module for calculating the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship, and establishing a core coolant flow distribution map based on the coolant flow distribution relationship;

[0096] The output module is used to determine whether the cooling channel is blocked based on the core coolant flow distribution diagram.

[0097] Example 3

[0098] This embodiment provides a computer-readable medium having a computer program stored thereon. The computer program is executed by a processor to implement the cooling channel blockage monitoring method based on neutron noise signals as described in Example 1. Specifically, the following steps are performed:

[0099] Step 1: deploying multiple self-powered neutron detectors in the reactor and collecting neutron noise signal data measured by each powered neutron detector;

[0100] Step 2: preprocessing the neutron noise signal data;

[0101] Step 3: Calculate the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship, and establish a core coolant flow distribution map based on the coolant flow distribution relationship;

[0102] Step 4: Determine whether the cooling channel is blocked based on the core coolant flow distribution diagram.

[0103] Example 4

[0104] This embodiment uses the neutron noise signal of the rhodium self-powered neutron detector to analyze the blockage of the cooling flow channel, specifically including:

[0105] Multiple self-powered neutron detectors are arranged in the reactor: a first control rod assembly and a second control rod assembly are determined according to condition a; condition a: there is no control rod assembly around the first control rod assembly or it is the second control rod assembly; a neutron measurement channel is provided at the center of the first control rod assembly along the control rod insertion direction, and multiple self-powered neutron detectors are arranged at equal depths in each neutron measurement channel. In the specific implementation process, seven rhodium self-powered neutron detectors are arranged at equal depths in each neutron measurement channel in this embodiment.

[0106] The neutron noise signal data in the rhodium self-powered neutron detector is collected. The neutron noise signal data includes neutron current signal noise data. The specific neutron noise signal data δφ(r,t) is:

[0107] δφ(r,t)=cδi(r,t)=c[i(r,t)-E(i(r,t))]

[0108] where δi(r,t) represents the neutron current signal noise data; E(·) represents the time-scale mean of the signal; i(r,t) represents the neutron current signal, r represents the position of the core, and t represents time; c represents the linear conversion coefficient of the self-powered neutron detector.

[0109] First, the linear conversion coefficient H(ω) of the rhodium self-powered neutron detector is calculated based on its response to neutron flux:

[0110]

[0111] In the formula, λ1 and λ2 represent and The decay constants are 0.016s -1 and 0.0027s -1 , N(ω) represents the neutron flux density at the rhodium self-powered neutron detector, I(ω) represents the output current of the rhodium self-powered neutron detector, a1 and a2 represent and The current share caused by , c represents the instantaneous response component of the rhodium self-powered neutron detector current, are all less than 1, ω is taken in the fuel vibration range (4π, 120π), in this range, the first-order term and the second-order term of the transfer function are much smaller than the constant term, and the neutron current signal fluctuation component and the neutron noise signal data are approximately linearly related, that is:

[0112]

[0113] The cross-correlation function is calculated for two different neutron noise signals of seven rhodium self-powered neutron detectors arranged at different heights in the same neutron measurement channel, namely:

[0114]

[0115] Where S ii (r,ω) represents the self-power spectrum density of the rhodium self-powered neutron detector i; S jj (r,ω) represents the power spectrum density of the rhodium self-powered neutron detector j; S ij(r, ω) represents the cross-power spectral density of the Rh self-powered neutron detector i and the Rh self-powered neutron detector j; where i, j (i, j = 1, 2, 3, 4, 5, 6, 7, …, n); n is the total number of Rh self-powered neutron detectors belonging to the same neutron measurement channel; r represents the position of the self-powered neutron detector, and ω represents the circular frequency of the neutron noise signal ω = 2πf.

[0116] The cross-correlation function results are as follows Figure 3 As shown, the trough structures in all the images are identified, and the frequency difference Δf between two trough structures in different interval images is calculated. ij , such as for Figure 3 The neutron detector cross-correlation function with an interval of 1, Δf ij ≈6.3Hz*2, the neutron detector cross-correlation function with an interval of 2, Δf ij ≈3.1Hz*2, neutron detector cross-correlation function with interval of 3, Δf ij ≈6.3-2.2=4.1Hz, the cross-correlation function of the neutron detector with an interval of 4, Δf ij ≈4.8-1.8=3Hz, the cross-correlation function of the neutron detector with an interval of 5, Δf ij ≈3.8-1.4=2.4Hz, the cross-correlation function of the neutron detector with an interval of 6, Δf ij ≈3.2-1.2=2Hz

[0117] Calculate the delay time τ of power fluctuation under coolant flow traction ij :

[0118]

[0119] At the same time, the distance d between the rhodium self-powered neutron detector i and the rhodium self-powered neutron detector j is calculated. ij :

[0120] d ij =|z i -z j |

[0121] z i represents the position of neutron measurement channel i; z j Indicates the position of neutron measurement channel j.

[0122] Use the least squares method to obtain the coolant flow rate corresponding to the current neutron measurement channel:

[0123]

[0124] Calculate the coolant flow rate corresponding to the neutron measurement channel, and use the spline curve fitting method to fit the core flow rate, specifically according to the following fitting formula:

[0125]

[0126] Where v(r) represents the fitting flow at r, Δr i =r i -r i-1 =(Δx i ,Δy i )=(x i -x i-1 ,y i -y i-1 ) represents the grid size, r i and v i Represent the position value and flow value of the known neutron measurement channel, M i represents the bending moment parameter obtained by solving the following set of equations:

[0127]

[0128] Indicates infinite approach to x from the positive direction i ; Indicates that it approaches x infinitely from the negative direction i ; Indicates infinite approach to y from the positive direction i ; Indicates infinite approach to y from the positive direction i ; r i - Indicates infinite approach to r from the positive direction i ; r i + Indicates infinite approach to r from the positive direction i .

[0129] Based on the core coolant flow distribution diagram and combined with the threshold, it is determined whether there is flow channel blockage; specifically, a blocking flow threshold is pre-set, and each coolant flow in the core coolant flow distribution diagram is compared with the blocking flow threshold. If the coolant flow at the current position exceeds the blocking flow threshold, it is determined that the flow channel at the current position is blocked; otherwise, it is determined that the flow channel at the current position is normal. Finally, the normal flow channel and the blocked flow channel are distinguished and displayed in the core coolant flow distribution diagram.

[0130] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0131] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0132] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0133] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A cooling channel blockage monitoring method based on neutron noise signals, characterized in that: include: Multiple self-powered neutron detectors are deployed in the reactor to collect neutron noise signal data measured by the self-powered neutron detectors; Preprocessing the neutron noise signal data; Includes methods: separating an AC signal and a DC signal from the neutron noise signal data, and amplifying the AC signal; sampling the DC signal and the amplified AC signal respectively, and filtering the amplified AC signal to obtain a first AC signal; dividing the first AC signal by the DC signal; Calculating the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship, and establishing a core coolant flow distribution diagram based on the coolant flow distribution relationship; calculating the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish the coolant flow distribution relationship; The method includes: obtaining neutron noise signal data of each energized neutron detector; Performing cross-correlation calculations between self-powered neutron detectors at different depths within the same neutron measurement channel; performing trough identification based on the cross-correlation calculation results, and calculating the coolant flow rate corresponding to the current neutron measurement channel based on the trough identification results; The cross-correlation calculation between self-powered neutron detectors at different depths in the same neutron measurement channel includes the following method: The cross-correlation function between the self-powered neutron detector i and the self-powered neutron detector j is calculated according to the following formula: Where, represents the self-power spectrum density of the self-powered neutron detector i; represents the self-power spectrum density of the self-powered neutron detector j; represents the cross-power spectral density of the self-powered neutron detector i and represents the cross-power spectral density of the self-powered neutron detector j; where i, j (i, j = 1, 2, 3, 4, 5, 6, 7, ..., n); n is the total number of self-powered neutron detectors belonging to the same neutron measurement channel; r represents the position of the self-powered neutron detector, represents the circular frequency of the neutron noise signal; The method of performing trough identification based on the cross-correlation calculation result and calculating the coolant flow rate corresponding to the current neutron measurement channel based on the trough identification result includes: Based on the cross-correlation function between self-powered neutron detector i and self-powered neutron detector j, calculate The frequency difference between the two trough structures , if the cross-correlation function has only one trough, take the frequency corresponding to the first trough and multiply the frequency value by 2; Calculate the coolant flow rate v corresponding to the current neutron measurement channel according to the following formula: in, It represents the delay time of power fluctuation under the traction of coolant flow between the trough structure corresponding to self-powered neutron detector i and the trough structure corresponding to self-powered neutron detector j. represents the frequency difference between the trough structure corresponding to the self-powered neutron detector i and the trough structure corresponding to the self-powered neutron detector j; d ij represents the distance between self-powered neutron detector i and self-powered neutron detector j; ； z i represents the height of the self-powered neutron detector i; z j represents the height of the self-powered neutron detector j; Determine whether the cooling channel is blocked based on the core coolant flow distribution diagram.

2. The cooling channel blockage monitoring method based on neutron noise signal according to claim 1 is characterized in that: The method of deploying multiple self-powered neutron detectors in a reactor includes: The first control rod assembly and the second control rod assembly are determined according to condition a; condition a: there is no control rod assembly around the first control rod assembly or the first control rod assembly is the second control rod assembly; A neutron measurement channel is arranged at the center of the first control rod assembly along the control rod insertion direction, and a plurality of self-powered neutron detectors are arranged at equal depth intervals in each neutron measurement channel.

3. The cooling channel blockage monitoring method based on neutron noise signal according to claim 1, characterized in that: The neutron noise signal data includes neutron current signal noise data; Neutron noise signal data for: Where, represents the neutron current signal noise data; Indicates taking the time-scale mean of the signal; ; c represents the linear conversion coefficient of the self-powered neutron detector.

4. The cooling channel blockage monitoring method based on neutron noise signal according to claim 1, characterized in that: The method of establishing a core coolant flow distribution diagram according to the coolant flow distribution relationship includes: Calculate the coolant flow rate corresponding to each neutron measurement channel; The core flow rate is calculated based on the coolant flow rate corresponding to each neutron measurement channel and the spline curve, and the core coolant flow distribution diagram is drawn.

5. A cooling channel blockage monitoring system based on neutron noise signals, characterized in that: A system for implementing the cooling channel blockage monitoring method based on neutron noise signals according to any one of claims 1 to 4, comprising: An acquisition module is used to deploy multiple self-powered neutron detectors in the reactor and collect neutron noise signal data measured by each of the self-powered neutron detectors; A preprocessing module, used for preprocessing the neutron noise signal data; a calculation module for calculating the flow rate of the reactor coolant based on the preprocessed neutron noise signal data to establish a coolant flow distribution relationship, and establishing a core coolant flow distribution map based on the coolant flow distribution relationship; The output module is used to determine whether the cooling channel is blocked based on the core coolant flow distribution diagram.

6. A computer-readable medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement the cooling channel blockage monitoring method based on neutron noise signals as described in any one of claims 1 to 4.

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