Cooling flow channel blocking monitoring method and system based on neutron noise signals and medium

Abstract

The invention discloses a cooling flow channel blocking monitoring method and system based on neutron noise signals and a medium. Relates to the technical field of cooling runner monitoring. The method comprises the following steps: arranging a plurality of self-powered neutron detectors in a reactor, and collecting neutron noise signal data measured by the self-powered neutron detectors; establishing a coolant flow distribution relation based on the neutron noise signal data to obtain a reactor core coolant flow distribution diagram; judging whether a cooling flow channel is blocked or not according to the reactor core coolant flow distribution diagram; the problem that in-reactor flow channel blockage abnormity cannot be monitored is solved, local overheating of the fuel assembly caused by flow channel blockage is avoided, and the safety and reliability of a reactor core are powerfully guaranteed.

Description

Technical Field

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

[0002] The lower grid plate of the reactor is an important part of the internal components of a nuclear power plant, and is also an important channel for the flow of coolant in the core of a nuclear power plant. During the operation of the reactor, the flow channel of the lower grid plate is often blocked due to coolant scaling and foreign matter, resulting in local overheating. In severe cases, it causes local boiling of the reactor core, causing impacts on the reactor fuel assemblies and control rods, threatening the safety of the reactor core.

[0003] Since the fuel assembly is located inside the reactor, the surrounding radioactivity is high and the space is small, it is impossible to arrange vibration detectors inside the reactor to detect the abnormal state 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 not only sensitive to thermal-hydraulic phenomena (acoustic standing 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 find 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 core safety; 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 diagram; judging whether the cooling flow channel is blocked according to the core coolant flow distribution diagram; 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] Arrange a plurality of self-powered neutron detectors in the reactor to collect neutron noise signal data measured by the respective 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 diagram according to the coolant flow distribution relationship;

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

[0012] Working principle of this scheme: 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 abnormal conditions 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, 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 diagram; determines whether cooling flow 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.

[0013] The traditional method for judging the abnormal state of reactor cooling channel blockage is mainly to collect the temperature data of the channel and analyze the temperature data to judge the abnormal situation of the channel. However, on the one hand, the temperature sensor not only collects the temperature of the channel, but also superimposes the data of other operating equipment near the channel, which leads to certain accuracy problems in analyzing the abnormal situation of the channel based on the temperature data. On the other hand, in the actual operation process, due to the complex bending structure of the channel, the position of the temperature sensor is difficult to achieve uniform layout, which leads to certain accuracy problems in analyzing the abnormal situation of the channel based on the temperature data. This scheme arranges multiple self-powered neutron detectors in the reactor to collect the neutron noise signal data measured by each self-powered neutron detector; and establishes the coolant flow distribution relationship based on the neutron noise signal data to obtain the core coolant flow distribution map; determines whether the cooling channel is blocked according to the core coolant flow distribution map; solves the problem that the abnormal blockage of the channel in the reactor cannot be monitored. The traditional method of judging local channel blockage based on temperature is to use the temperature probe arranged in the core. When the channel blockage occurs in the core, the local temperature rises. This method can only be qualitatively observed when the 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.

[0014] A further optimization scheme 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 scheme 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 noise data of the neutron current signal; 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 the 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 method:

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

[0023] The DC signal and the amplified AC signal are sampled respectively, and the amplified AC signal is filtered 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 method:

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

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

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

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

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

[0031]

[0032] In the formula, S ii (r,ω) represents the self-power spectrum density of the self-powered neutron detector i; S jj (r,ω) represents the self-power spectrum density of the self-powered neutron detector j; S ij (r, ω) represents the cross-power spectral density of the self-powered neutron detector i and 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, and ω represents the circular frequency of the neutron noise signal.

[0033] A further optimization scheme is that the trough structure is identified according to the cross-correlation calculation result, and the coolant flow rate corresponding to the current neutron measurement channel is calculated according to the trough structure identification result, including the 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 the self-powered neutron detector i and the trough structure corresponding to the 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 the self-powered neutron detector i and the 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 method:

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

[0042] The core flow rate is fitted 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] The present 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 arrange multiple self-powered neutron detectors in the reactor and collect neutron noise signal data measured by each powered neutron detector;

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

[0046] A calculation module, used 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 diagram according to the coolant flow distribution relationship;

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

[0048] The present solution also provides a computer-readable medium on which a computer program is stored. The computer program is executed by a processor to implement the cooling 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 signal provided by the present invention are methodological improvements based on the 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 blockage of the flow channel in the reactor cannot be monitored, avoids local overheating of the fuel assembly 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 embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0052] Figure 1 It is a schematic diagram of the flow of a cooling channel blockage monitoring method based on neutron noise signals;

[0053] Figure 2 It is a schematic diagram of the structure of the cooling channel blockage monitoring system based on neutron noise signals;

[0054] Figure 3 Schematic diagram of the cross-correlation function result 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 embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0056] Since the fuel assembly is located in the reactor, the surrounding radioactivity 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 and introduce potential risks to the core safety. 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: deploy multiple self-powered neutron detectors in the reactor and collect neutron noise signal data measured by each powered neutron detector;

[0060] The method of arranging a plurality of 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 noise data of the neutron current signal; 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 the 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] The DC signal and the amplified AC signal are sampled respectively, and the amplified AC signal is filtered to obtain a first AC signal;

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

[0071] Step 3, 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 according to 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: A cross-correlation function;

[0075]

[0076] In the formula, S ii (r,ω) represents the self-power spectrum density of the self-powered neutron detector i; S jj (r,ω) represents the self-power spectrum density of the self-powered neutron detector j; S ij (r, ω) represents the cross-power spectral density of the self-powered neutron detector i and the self-powered neutron detector 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 according to the cross-correlation calculation result, and the coolant flow rate corresponding to the current neutron measurement channel is calculated according to 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, neutron detector cross-correlation function with interval 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 detectors with an interval of 4, Δf ij ≈4.8-1.8=3Hz, neutron detector cross-correlation function with interval 5, Δf ij ≈3.8-1.4=2.4Hz, the cross-correlation function of the neutron detectors 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 the self-powered neutron detector i and the trough structure corresponding to the 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 the self-powered neutron detector i and the 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 fitted 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 according to the core coolant flow distribution diagram; specifically, the method includes:

[0088] A blocking flow threshold is set in advance, 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, 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 channel blockage is mainly to collect the temperature data of the channel and analyze the temperature data to judge the abnormal situation of the channel. However, on the one hand, the temperature sensor not only collects the temperature of the channel, but also superimposes the data of other operating equipment near the channel, resulting in certain accuracy problems in analyzing the abnormal situation of the channel based on the temperature data. On the other hand, in the actual operation process, due to the complex bending structure of the channel, the points of the temperature sensor are difficult to be evenly arranged, resulting in certain accuracy problems in analyzing the abnormal situation of the channel based on the temperature data. This scheme arranges multiple self-powered neutron detectors in the reactor to collect the neutron noise signal data measured by each self-powered neutron detector; and establishes the coolant flow distribution relationship based on the neutron noise signal data to obtain the core coolant flow distribution map; determines whether the cooling channel is blocked according to the core coolant flow distribution map; solves the problem that the abnormal blockage of the channel in the reactor cannot be monitored; the traditional method of judging local channel blockage based on temperature is to use the temperature probe arranged in the core. When the channel blockage occurs in the core, the local temperature rises. This method can only perform qualitative observation when the 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 comprises:

[0092] The acquisition module is used to collect neutron noise signal data measured by each self-powered neutron detector; the specific acquisition module includes a plurality of self-powered neutron detectors arranged in the reactor: 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 it is the second control rod assembly; a neutron measurement channel is set at the center position 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.

[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 the 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, used 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 diagram according to the coolant flow distribution relationship;

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

[0097] Example 3

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

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

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

[0101] Step 3, 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 according to 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] A plurality of self-powered neutron detectors are arranged in the reactor: 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 it is the second control rod assembly; a neutron measurement channel is set at the center position of the first control rod assembly along the control rod insertion direction, and a plurality of self-powered neutron detectors are arranged at equal depths in each neutron measurement channel. In the specific implementation process, 7 rhodium self-powered neutron detectors are arranged at equal depths in each neutron measurement channel of this embodiment.

[0106] The neutron noise signal data in the rhodium self-powered neutron detector is collected, and 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 noise data of the neutron current signal; 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 the 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 by the response mode of the rhodium self-powered neutron detector to the neutron flux:

[0110]

[0111] In the formula, λ 1 , 2 Respectively 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, a 1 、a 2 Respectively 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] In the formula, S ii (r,ω) represents the self-power spectrum density of the rhodium self-powered neutron detector i; S jj (r,ω) represents the self-power spectrum density of the rhodium self-powered neutron detector j; S ij(r, ω) represents the mutual power spectral density of the rhodium self-powered neutron detector i and the rhodium self-powered neutron detector j; where i, j (i, j = 1, 2, 3, 4, 5, 6, 7, ..., n); n is the total number of rhodium 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, neutron detector cross-correlation function with interval 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 detectors with an interval of 4, Δf ij ≈4.8-1.8=3Hz, neutron detector cross-correlation function with interval 5, Δf ij ≈3.8-1.4=2.4Hz, the cross-correlation function of the neutron detectors with an interval of 6, Δf ij ≈3.2-1.2=2Hz

[0117] Calculate the delay time τ of power fluctuation under the traction of coolant flow 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] The coolant flow rate corresponding to the neutron measurement channel is calculated, and the core flow rate is fitted using the spline curve fitting method, specifically according to the following fitting formula:

[0125]

[0126] In the formula, 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 Respectively 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 equations:

[0127]

[0128] Indicates that it approaches x infinitely 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] According to the core coolant flow distribution diagram, it is judged whether there is flow channel blockage in combination with the threshold. Specifically, the 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 may be provided as methods, systems, or computer program products. Therefore, the present application may 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 may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include 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 generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. 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 capable of directing a computer or other programmable data processing device to operate 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 A 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: Arrange a plurality of self-powered neutron detectors in the reactor to collect neutron noise signal data measured by the respective powered neutron detectors; Preprocessing the neutron noise signal data; 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 according to the coolant flow distribution relationship; Determine whether cooling channel blockage occurs 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 arranging a plurality of 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 is characterized in that: The neutron noise signal data includes neutron current signal noise data; The neutron noise signal data δφ(r,t) is: δφ(r,t)=cδi(r,t)=c[i(r,t)-E(i(r,t))] Where δi(r,t) represents the noise data of the neutron current signal; 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 the time; 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 is characterized in that: The preprocessing of the neutron noise signal data comprises a method: Separating an AC signal and a DC signal from the neutron noise signal data, and amplifying the AC signal; The DC signal and the amplified AC signal are sampled respectively, and the amplified AC signal is filtered to obtain a first AC signal; The first AC signal is divided by the DC signal.

5. The cooling channel blockage monitoring method based on neutron noise signal according to claim 2 is characterized in 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; Included methods: Acquiring neutron noise signal data of each energized neutron detector; Performing cross-correlation calculation between self-powered neutron detectors at different depths in the same neutron measurement channel; The trough is identified according to the cross-correlation calculation result, and the coolant flow rate corresponding to the current neutron measurement channel is calculated according to the trough identification result.

6. The cooling channel blockage monitoring method based on neutron noise signal according to claim 5 is characterized in that: The cross-correlation calculation between the 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: In the formula, S ii (r,ω) represents the self-power spectrum density of the self-powered neutron detector i; S jj (r,ω) represents the self-power spectrum density of the self-powered neutron detector j; S ij (r, ω) represents the cross-power spectral density of the self-powered neutron detector i and 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, and ω represents the circular frequency of the neutron noise signal.

7. The cooling channel blockage monitoring method based on neutron noise signal according to claim 5 is characterized in that: The method of performing trough identification according to the cross-correlation calculation result and calculating the coolant flow rate corresponding to the current neutron measurement channel according to the trough identification result includes: 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; Calculate the coolant flow rate v corresponding to the current neutron measurement channel according to the following formula: Among them, τ ij It represents the delay time of power fluctuation under the traction of coolant flow between the trough structure corresponding to the self-powered neutron detector i and the trough structure corresponding to the 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 the self-powered neutron detector i and the self-powered neutron detector j; d ij =|z i -z 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.

8. The cooling channel blockage monitoring method based on neutron noise signal according to claim 5 is 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 fitted 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.

9. A cooling channel blockage monitoring system based on neutron noise signals, characterized in that: A cooling channel blockage monitoring method based on neutron noise signals is used to implement any one of claims 1 to 8, the system comprising: An acquisition module is used to arrange multiple self-powered neutron detectors in the reactor and collect neutron noise signal data measured by each powered neutron detector; A preprocessing module, used for preprocessing the neutron noise signal data; A calculation module, used 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 diagram according to the coolant flow distribution relationship; The output module is used to determine whether the cooling channel is blocked according to the core coolant flow distribution diagram.

10. 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 8.

Images