Reactor core power monitoring method and device, electronic equipment and monitoring system

Abstract

The invention provides a reactor core power monitoring method and device, electronic equipment and a monitoring system, and relates to the technical field of nuclear reactor engineering. The method comprises the following steps: acquiring current state information of a target reactor and current nuclear measurement signals of multiple groups of out-of-core detectors; the target reactor corresponds to the out-of-pile detector; determining a current high-order harmonic wave corresponding to the target reactor according to the current state information; determining reactor core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset out-of-reactor detector response matrix and the current nuclear measurement signal; the target high-order harmonic is a high-order harmonic selected from the current high-order harmonic; the preset out-of-pile detector response matrix corresponds to the out-of-pile detector; the preset number is smaller than the group number of the out-of-pile detectors. According to the embodiment of the invention, the method does not need to establish a harmonic database in advance, occupies a small memory, and also improves the precision of reactor core power monitoring.

Description

Technical Field

[0001] This application belongs to the technical field of nuclear reactor engineering, and particularly relates to a core power monitoring method, device, electronic device, and monitoring system. Background Art

[0002] Due to the characteristics of miniaturization, modularization, and high efficiency, micro nuclear reactors are applicable to various special and daily scenarios. For example, they can provide stable electricity and heat energy for polar regions, deserts, mountains, or remote areas lacking a reliable power grid. They can also be loaded onto trucks or ships to provide emergency energy supply in the event of earthquakes, floods, or other disasters.

[0003] In related technologies, the online monitoring of micro nuclear reactors mainly relies on a small number of off-core detectors to obtain nuclear measurement signals, and determines the core power based on the nuclear measurement signals. Due to the small number of off-core detectors, it has a greater impact on the accuracy of online monitoring. Taking the core power monitoring method based on data-driven as an example, to solve the above impact, it is necessary to pre-establish a harmonic database covering a large number of operating conditions, which occupies a huge amount of memory, and for operating conditions not covered in the database, the monitoring accuracy is relatively low.

[0004] Therefore, the monitoring methods in related technologies are difficult to meet the accuracy requirements of online monitoring of micro nuclear reactors and need to be further optimized. Summary of the Invention

[0005] The technical problem to be solved by this application is to provide a core power monitoring method, device, electronic device, and monitoring system in view of the above deficiencies in the prior art. Using this core power monitoring method can improve the accuracy of core power monitoring.

[0006] In a first aspect, an embodiment of this application provides a core power monitoring method, including:

[0007] Obtain the current status information of the target reactor and the current nuclear measurement signals of multiple groups of off-core detectors; the target reactor corresponds to the off-core detectors;

[0008] Determine the current high-order harmonics corresponding to the target reactor according to the current status information;

[0009] Determine the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset off-core detector response matrix, and the current nuclear measurement signals; the target high-order harmonics are the high-order harmonics selected from the current high-order harmonics; the preset off-core detector response matrix corresponds to the off-core detectors; the preset number is less than the number of groups of the off-core detectors.

[0010] In some embodiments of the first aspect, determining the current high-order harmonic corresponding to the target reactor according to the current state information includes:

[0011] Determining a corresponding preset constant according to the current state information; the preset constant is related to calculating the current high-order harmonic;

[0012] Inputting the preset constant into a preset multi-group diffusion equation;

[0013] Solving the preset multi-group diffusion equation based on an outer iteration solution method to generate a corresponding solution result;

[0014] Determining the current high-order harmonic according to the solution result and the preset constant.

[0015] In some embodiments of the first aspect, determining the current high-order harmonic according to the solution result and the preset constant includes:

[0016] Inputting the solution result and the preset constant into a preset high-order flux algorithm and a preset high-order adjoint flux algorithm;

[0017] Solving the preset high-order flux algorithm and the preset high-order adjoint flux algorithm based on an iterative solution method to generate a corresponding high-order flux;

[0018] Inputting the high-order flux into a preset high-order fission reaction rate algorithm to determine a corresponding high-order fission reaction rate based on the preset high-order fission reaction rate algorithm;

[0019] Determining the current high-order harmonic according to the high-order fission reaction rate.

[0020] In some embodiments of the first aspect, determining the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset out-of-core detector response matrix, and the current nuclear measurement signal includes:

[0021] Determining the product between the high-order harmonic matrix and the preset out-of-core detector response matrix to generate a corresponding product result; the high-order harmonic matrix is constructed based on a preset number of target high-order harmonics;

[0022] Determining the core power distribution according to the product result and the current nuclear measurement signal.

[0023] In some embodiments of the first aspect, determining the core power distribution according to the product result and the current nuclear measurement signal includes:

[0024] Inputting the product result and the current nuclear measurement signal into a preset matrix equation;

[0025] Solve the preset matrix equation using the least squares method to generate the corresponding equation coefficients;

[0026] Input the equation coefficients and the high-order harmonic matrix into a preset core power determination algorithm to generate the core power distribution based on the preset core power determination algorithm.

[0027] In some embodiments of the first aspect, before determining the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset out-of-core detector response matrix, and the current nuclear measurement signal, the method further includes:

[0028] Screen a preset number of symmetric high-order harmonics from all current high-order harmonics;

[0029] Determine the symmetric high-order harmonics as the target high-order harmonics.

[0030] In some embodiments of the first aspect, the preset number is greater than or equal to three;

[0031] Before screening a preset number of symmetric high-order harmonics from all current high-order harmonics, the method further includes:

[0032] Determine the total number of symmetric high-order harmonics among all current high-order harmonics;

[0033] If the total number is greater than or equal to four, determine the preset number to be three or four;

[0034] If the total number is equal to three, determine the preset number to be three.

[0035] In some embodiments of the first aspect, before determining the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset out-of-core detector response matrix, and the current nuclear measurement signal, the method further includes:

[0036] Construct a reactor model corresponding to the target reactor using a Monte Carlo nuclear design program;

[0037] Calculate the out-of-core detector response matrix between each fuel assembly and the out-of-core detector in the reactor model using a Monte Carlo nuclear design program.

[0038] Based on the same inventive concept, in a second aspect, an embodiment of the present application further provides a core power monitoring device, including:

[0039] An acquisition module for acquiring the current state information of the target reactor and the current nuclear measurement signals of multiple groups of out-of-core detectors; the target reactor corresponds to the out-of-core detectors;

[0040] A first determination module, configured to determine a current high-order harmonic corresponding to a target reactor according to the current state information;

[0041] A second determination module, configured to determine a core power distribution corresponding to a target reactor according to a preset number of target high-order harmonics, a preset out-of-core detector response matrix, and the current nuclear measurement signal; the target high-order harmonics are high-order harmonics selected from the current high-order harmonics; the preset out-of-core detector response matrix corresponds to the out-of-core detector; the preset number is less than the number of groups of the out-of-core detectors.

[0042] In some embodiments of the second aspect, the first determination module is specifically configured to:

[0043] Determine a corresponding preset constant according to the current state information; the preset constant is related to calculating the current high-order harmonic; input the preset constant into a preset multi-group diffusion equation; solve the preset multi-group diffusion equation based on an outer iteration solution method to generate a corresponding solution result; determine the current high-order harmonic according to the solution result and the preset constant.

[0044] In some embodiments of the second aspect, when the first determination module determines the current high-order harmonic according to the solution result and the preset constant, it is specifically configured to:

[0045] Input the solution result and the preset constant into a preset high-order flux algorithm and a preset high-order adjoint flux algorithm; solve the preset high-order flux algorithm and the preset high-order adjoint flux algorithm based on an iterative solution method to generate a corresponding high-order flux; input the high-order flux into a preset high-order fission reaction rate algorithm to determine a corresponding high-order fission reaction rate based on the preset high-order fission reaction rate algorithm; determine the current high-order harmonic according to the high-order fission reaction rate.

[0046] In some embodiments of the second aspect, the second determination module is specifically configured to:

[0047] Determine the product between a high-order harmonic matrix and the preset out-of-core detector response matrix to generate a corresponding product result; the high-order harmonic matrix is constructed and generated based on a preset number of target high-order harmonics; determine the core power distribution according to the product result and the current nuclear measurement signal.

[0048] In some embodiments of the second aspect, when the second determination module determines the core power distribution according to the product result and the current nuclear measurement signal, it is specifically configured to:

[0049] Input the product result and the current nuclear measurement signal into a preset matrix equation; solve the preset matrix equation using the least squares method to generate corresponding equation coefficients; input the equation coefficients and the high-order harmonic matrix into a preset core power determination algorithm to generate the core power distribution based on the preset core power determination algorithm.

[0050] In some embodiments of the second aspect, the device further includes:

[0051] A screening module, configured to screen a preset number of symmetric high-order harmonics from all current high-order harmonics; determine the symmetric high-order harmonics as the target high-order harmonics.

[0052] In some embodiments of the second aspect, the preset number is greater than or equal to three;

[0053] The screening module is further configured to:

[0054] Determine the total number of symmetric high-order harmonics among all current high-order harmonics; if the total number is greater than or equal to four, determine the preset number as three or four; if the total number is equal to three, determine the preset number as three.

[0055] In some embodiments of the second aspect, the device further includes:

[0056] A construction module, configured to construct a reactor model corresponding to the target reactor using a Monte Carlo nuclear design program; calculate an out-of-core detector response matrix between each fuel assembly and the out-of-core detector in the reactor model using the Monte Carlo nuclear design program.

[0057] Based on the same inventive concept, in a third aspect, an embodiment of the present application further provides an electronic device, which includes:

[0058] A memory and a processor;

[0059] The memory stores computer execution instructions;

[0060] The processor executes the computer execution instructions stored in the memory to implement the core power monitoring method according to any one of the first aspect.

[0061] Based on the same inventive concept, in a fourth aspect, an embodiment of the present application further provides a monitoring system, which includes:

[0062] The electronic device as described in the third aspect; the electronic device is used to implement the core power monitoring method according to any one of the first aspect.

[0063] According to the core power monitoring method, device, electronic device and monitoring system provided by the embodiments of the present application, by obtaining the current state information of the target reactor and the current nuclear measurement signals of multiple sets of off-core detectors, and determining the current high-order harmonics corresponding to the target reactor according to the current state information. The current high-order harmonics are related to the current state of the target reactor, can reflect the core power situation under the current working condition of the target reactor, and do not need to establish a harmonic database in advance, occupying less memory. At the same time, according to a preset number of target high-order harmonics, a preset off-core detector response matrix and the current nuclear measurement signals, the core power distribution corresponding to the target reactor is determined, and this core power distribution is closer to the actual situation of the target reactor and has higher accuracy. Therefore, the core power monitoring method provided by the embodiments of the present application improves the accuracy of core power monitoring. Description of the Drawings

[0064] Figure 1 Fig. shows a schematic flow chart of a core power monitoring method provided by an embodiment of the present application;

[0065] Figure 2 Fig. shows another schematic flow chart of a core power monitoring method provided by an embodiment of the present application;

[0066] Figure 3 Fig. shows a schematic structural diagram of a core provided by an embodiment of the present application;

[0067] Figure 4 Fig. shows a schematic diagram of eigenvalue change provided by an embodiment of the present application;

[0068] Figure 5 Fig. shows a schematic diagram of high-order harmonics provided by an embodiment of the present application;

[0069] Figure 6 Fig. shows a schematic diagram of core power distribution provided by an embodiment of the present application;

[0070] Figure 7 Fig. shows another schematic diagram of core power distribution provided by an embodiment of the present application;

[0071] Figure 8 Fig. shows a schematic diagram of core power error distribution provided by an embodiment of the present application;

[0072] Figure 9 Fig. shows a schematic structural diagram of a core power monitoring device provided by an embodiment of the present application. Detailed Embodiments

[0073] To enable those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below with reference to the drawings and embodiments.

[0074] The features and exemplary embodiments of various aspects of the present application will be described in detail below. To make the objectives, technical solutions, and advantages of the present application clearer, the following further describes the present application in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0075] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "including..." do not exclude the existence of additional identical elements in the process, method, article or device including the said elements.

[0076] As described in the background art, the monitoring method in the related art is affected by the number of off-core detectors, and it is necessary to pre-establish a harmonic database covering a large number of operating conditions, which occupies a huge amount of memory. Moreover, for operating conditions not covered in the database, the monitoring accuracy is relatively low, and it is difficult to meet the accuracy requirements for on-line monitoring of a micro nuclear reactor, and further optimization is needed.

[0077] Embodiment 1

[0078] The core power monitoring method provided by the embodiment of the present application is applicable to the process of monitoring the core power of a micro reactor. The core power monitoring method can be executed by a core power monitoring device, an electronic device, etc. Hereinafter, an example will be given in which the core power monitoring method is executed by an electronic device.

[0079] As Figure 1 shown, the core power monitoring method provided by the embodiment of the present application may include steps S101 to S103.

[0080] S101. Obtain the current state information of the target reactor and the current nuclear measurement signals of multiple groups of off-core detectors. Among them, the target reactor corresponds to the off-core detectors.

[0081] Exemplarily, the manner of obtaining the current state information of the target reactor and the current nuclear measurement signals of multiple sets of out-of-core detectors may be to obtain them from relevant devices for collecting information, or to obtain them from the monitoring devices corresponding to the target reactor. This embodiment does not limit this.

[0082] Exemplarily, the target reactor refers to a reactor for which core power monitoring is required, and the target reactor may be one or more.

[0083] Exemplarily, the current state information refers to relevant information that can represent the state of the target reactor, and the current state information includes information such as control rod position, temperature, burnup, and depth.

[0084] Exemplarily, the out-of-core detector can also be called an out-of-core neutron detector, and it can be arranged outside the steel shielding layer in the target reactor.

[0085] Exemplarily, the number of sets of out-of-core detectors can be set according to actual applications. For example, in the target reactor, 3 positions are selected in an asymmetric manner radially, and 4 sets of detectors are arranged axially at each position, that is, a total of 12 sets are arranged.

[0086] Exemplarily, the current nuclear measurement signal can be the neutron flux density collected by the out-of-core detector.

[0087] S102. Determine the current high-order harmonic corresponding to the target reactor according to the current state information.

[0088] Exemplarily, according to the current state information, constants related to calculating the current high-order harmonic can be called, so as to obtain the current high-order harmonic through calculation.

[0089] Exemplarily, the current state information adopted can be only the control rod position. By narrowing the scope of the current state information adopted, the data acquisition scope can be reduced, and the complexity of subsequent calculation processes can be reduced.

[0090] Exemplarily, the current high-order harmonic represents the current high-order harmonic of the target reactor, has real-time performance, and can reflect the current working condition of the target reactor.

[0091] S103. Determine the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset out-of-core detector response matrix, and the current nuclear measurement signal. Among them, the target high-order harmonic is the high-order harmonic selected from the current high-order harmonic. The preset out-of-core detector response matrix corresponds to the out-of-core detector. The preset number is less than the number of sets of out-of-core detectors.

[0092] Exemplarily, the preset number is related to the number of sets of out-of-core detectors. When the preset number is greater than or equal to the number of sets of out-of-core detectors, a definite core power distribution cannot be obtained.

[0093] Exemplarily, the preset quantity may be a relatively small quantity. For example, it may be three, four, five, etc.

[0094] Exemplarily, the target high-order harmonic may be a high-order harmonic selected from the current high-order harmonics according to preset conditions. For example, only symmetric high-order harmonics are selected.

[0095] Exemplarily, the preset out-of-core detector response matrix may be pre-stored in a preset database. Among them, the out-of-core detector response matrix is the core mathematical model in the core power monitoring of a nuclear reactor, which can reflect the quantitative relationship between the power distribution inside the core and the signals of the out-of-core detectors. For example, it can map the power contributions of each fuel assembly in the core to the current or count signals of the out-of-core detectors.

[0096] Exemplarily, the matrix size of the preset out-of-core detector response matrix is the number of out-of-core detector groups multiplied by the number of fuel sub-blocks divided in the core.

[0097] In some embodiments, before step S103, a construction process of the out-of-core detector response matrix may further be included, specifically as follows:

[0098] Use a Monte Carlo nuclear design program to construct a reactor model corresponding to the target reactor.

[0099] Use a Monte Carlo nuclear design program to calculate the out-of-core detector response matrix between each fuel sub-block and the out-of-core detectors in the reactor model.

[0100] Through the Monte Carlo nuclear design program, a reactor model corresponding to the target reactor can be constructed quickly and accurately, thereby constructing a more accurate out-of-core detector response matrix, improving the construction efficiency and construction accuracy. At the same time, through the accurate out-of-core detector response matrix, the accuracy of subsequent determination of the core power distribution can be improved.

[0101] Exemplarily, the reactor model includes in-core structures such as fuel assemblies, reflectors, control rods, coolants, etc.

[0102] Exemplarily, other types of programs may also be used to construct the reactor model, such as a deterministic program applicable to the target reactor type.

[0103] In some embodiments, before step S103, a screening process of high-order harmonics may further be included, specifically as follows:

[0104] Screen a preset number of symmetric high-order harmonics from all current high-order harmonics.

[0105] Determine the symmetric high-order harmonics as the target high-order harmonics.

[0106] Symmetrical harmonics in higher-order harmonics are more in line with physical and structural laws. Therefore, symmetrical higher-order harmonics are closer to the actual situation and have higher accuracy. By screening symmetrical higher-order harmonics from all current higher-order harmonics, the accuracy of the target higher-order harmonics can be improved, thereby improving the accuracy of subsequent determination of the core power distribution.

[0107] In some embodiments, the preset quantity is greater than or equal to three.

[0108] Before screening a preset quantity of symmetrical higher-order harmonics from all current higher-order harmonics, the specific value of the preset quantity can also be determined as follows:

[0109] Determine the total quantity of symmetrical higher-order harmonics among all current higher-order harmonics.

[0110] If the total quantity is greater than or equal to four, determine the preset quantity to be three or four.

[0111] If the total quantity is equal to three, determine the preset quantity to be three.

[0112] By determining the total quantity of symmetrical higher-order harmonics among the current higher-order harmonics, a basis can be provided for subsequent determination of the preset quantity, so as to reduce the specific value of the preset quantity, thereby reducing the quantity of higher-order harmonics used, and further reducing the computational complexity of subsequent determination of the core power distribution and improving the efficiency of determining the core power distribution. At the same time, when the preset quantity is greater than or equal to three, the accuracy requirements for the core power distribution of the micro reactor can also be met.

[0113] Exemplarily, the preset quantity can be set to three or four, so as to not only meet the accuracy requirements for the core power distribution of the micro reactor, but also improve the efficiency of determining the core power distribution.

[0114] According to the core power monitoring method provided by the embodiments of the present application, by obtaining the current state information of the target reactor and the current nuclear measurement signals of multiple sets of off-core detectors, and determining the current higher-order harmonics corresponding to the target reactor according to the current state information. The current higher-order harmonics are related to the current state of the target reactor, can reflect the core power situation under the current working condition of the target reactor, and do not require pre-establishment of a harmonic database, occupying less memory. At the same time, the core power distribution corresponding to the target reactor is determined according to the preset quantity of target higher-order harmonics, the preset off-core detector response matrix, and the current nuclear measurement signals, and this core power distribution is closer to the actual situation of the target reactor and has higher accuracy.

[0115] Embodiment 2

[0116] As Figure 2As shown in the figure, the core power monitoring method provided in the embodiment of the present application is further described on the basis of the core power monitoring method provided in Embodiment 1 of the present application, and may include steps S201 to S207. Among them, steps S202 to S205 can be replaced by step S102 in Embodiment 1. Steps S206 to S207 can be replaced by step S103 in Embodiment 1, and this embodiment does not limit this.

[0117] S201. Obtain the current state information of the target reactor and the current nuclear measurement signals of multiple sets of off-core detectors.

[0118] The implementation manner of step S201 is similar to that of step S101 in Embodiment 1, and will not be elaborated here.

[0119] S202. Determine the corresponding preset constant according to the current state information, where the preset constant is related to the calculation of the current high-order harmonic.

[0120] Exemplarily, the preset constant includes one or more of the following: diffusion coefficient, Laplace operator, fission spectrum, number of energy groups, number of neutrons released per fission, nodal position, axial number of layers, radial number of nodes, nodal volume, scattering matrix, etc.

[0121] Exemplarily, the preset constant can be stored in a preset database and has a mapping relationship with the current state information, and the corresponding preset constant can be directly called through the current state information.

[0122] S203. Input the preset constant into the preset multi-group diffusion equation.

[0123] Exemplarily, the preset multi-group diffusion equation is specifically as follows:

[0124]

[0125] In the formula, g is the incident energy group, g' is the outgoing energy group, D is the diffusion coefficient, ▽ 2 is the Laplace operator, representing the sum of the second-order derivatives in each coordinate direction, φ g and φ g' are the neutron flux rates of the incident energy group and the outgoing energy group respectively, Σ r is the removal cross section, which is calculated by the following formula:

[0126]

[0127] χ is the fission spectrum, k eff is the effective multiplication factor, Σ a，g is the absorption cross section of energy group g, G is the number of energy groups, ν is the number of neutrons released per fission, Σ f is the fission cross section, Σ s,g′→g is the scattering matrix, and ng represents the total number of energy groups.

[0128] Among them, the effective multiplication factor and the neutron fluence rate are variables.

[0129] S204. Solve the preset multi-group diffusion equation based on the outer iteration solution method to generate corresponding solution results.

[0130] Exemplarily, the outer iteration solution method can obtain the variable values of multiple iterations by performing multiple iterations on the preset multi-group diffusion equation. Calculate the difference between the variable value of the current iteration and the variable value of the previous iteration, and thus judge whether to converge based on the difference. For example, if the difference is less than the preset threshold, it is judged to converge. The finally converged variable value is the solution result.

[0131] S205. Determine the current high-order harmonic according to the solution result and the preset constant.

[0132] Based on the diffusion theory, the method of calculating the current high-order harmonic through the preset multi-group diffusion equation and the preset constant occupies less memory and can better reflect the actual working conditions compared with the method of pre-establishing a harmonic database covering a large number of operating conditions. The accuracy and precision of the determined current high-order harmonic are higher.

[0133] Exemplarily, after obtaining the solution result, it can be further calculated in combination with the preset constant to obtain the current high-order harmonic.

[0134] In some embodiments, step S205 may be specifically:

[0135] Input the solution result and the preset constant into the preset high-order flux algorithm and the preset high-order adjoint flux algorithm.

[0136] Solve the preset high-order flux algorithm and the preset high-order adjoint flux algorithm based on the iterative solution method to generate corresponding high-order fluxes.

[0137] Input the high-order flux into the preset high-order fission reaction rate algorithm to determine the corresponding high-order fission reaction rate based on the preset high-order fission reaction rate algorithm.

[0138] Determine the current high-order harmonic according to the high-order fission reaction rate.

[0139] The method of calculating the current high-order harmonic through the preset high-order flux algorithm, the preset high-order adjoint flux algorithm and the preset high-order fission reaction rate algorithm occupies less memory and can better reflect the actual working conditions compared with the method of pre-establishing a harmonic database covering a large number of operating conditions. At the same time, calculating by combining multiple algorithms can also improve the accuracy of the determined current high-order harmonic.

[0140] Exemplarily, the preset high-order flux algorithm is as follows:

[0141]

[0142] In the formula, l is the order of the flux, n is the highest order of the flux, k is the number of iterations, is the adjoint flux, s is the neutron fluence rate spectrum that has not been normalized during the outer iteration process, ψ is the fission reaction rate, r is the node position, nz is the number of axial layers, and nxy is the number of radial nodes.

[0143] The specific preset high-order adjoint flux algorithm is as follows:

[0144]

[0145] The parameters in the formula have the same meaning as those in the preset high-order flux algorithm.

[0146] The specific preset high-order fission reaction rate algorithm is as follows:

[0147]

[0148] In the formula, V is the node volume, and other parameters have the same meaning as those in the foregoing algorithms.

[0149] Exemplarily, multi-order high-order fluxes can be generated through an iterative solution method, such as third-order, fourth-order, fifth-order, etc.

[0150] Exemplarily, by solving the preset high-order flux algorithm and the preset high-order adjoint flux algorithm based on the iterative solution method, multi-order high-order adjoint fluxes can also be obtained, such as third-order, fourth-order, fifth-order, etc.

[0151] Exemplarily, according to the correspondence between the high-order fission reaction rate and the high-order harmonics, the current high-order harmonics corresponding to the high-order fission reaction rate can be determined.

[0152] S206. Determine the product between the high-order harmonic matrix and the preset out-of-core detector response matrix to generate a corresponding product result. Among them, the high-order harmonic matrix is constructed based on a preset number of target high-order harmonics.

[0153] S207. Determine the core power distribution according to the product result and the current nuclear measurement signal.

[0154] Exemplarily, perform a high-order harmonic expansion on the core power distribution P under any working condition:

[0155]

[0156] In the formula, f n is the expansion coefficient of the high-order harmonics, s n is the high-order harmonic, and M and x are the high-order harmonic matrix and the expansion coefficient vector (i.e., the equation coefficient), respectively.

[0157] For the core power distribution P, after being converted by the off-core detector response matrix D, the off-core detector readings (i.e., the numerical values of nuclear measurement signals) R are obtained, that is:

[0158] DP = R

[0159] By expanding the power distribution in harmonics, a preset matrix equation can be obtained:

[0160] DMx = R

[0161] Therefore, the problem of inversely solving the core power distribution based on the detector readings is transformed into the problem of solving the high-order harmonic coefficients x. When the number of harmonics is less than the number of detectors, the least squares method can be used to obtain the best fitting coefficients x. Combining with the high-order harmonics, the core power distribution can be obtained.

[0162] Since the high-order harmonics are theoretically complete, the power distribution under any working condition can be expanded by high-order harmonics, which is the basis for the high accuracy of on-line core power reconstruction. However, due to the limited number of detectors, a large number of high-order harmonics cannot be used for power reconstruction and on-line monitoring (when the number of harmonics is greater than the number of detectors, the underdetermined equation has no definite solution). A small number of harmonics can be selected on-line according to the actual working conditions. For a micro-reactor, when the number of harmonics is 3 - 4, it is sufficient to meet the engineering design accuracy requirements.

[0163] In some embodiments, step S207 may be specifically:

[0164] Input the product result and the current nuclear measurement signal into the preset matrix equation.

[0165] Solve the preset matrix equation using the least squares method to generate the corresponding equation coefficients.

[0166] Input the equation coefficients and the high-order harmonic matrix into the preset core power determination algorithm to generate the core power distribution based on the preset core power determination algorithm.

[0167] Since the power distribution under any working condition can be expanded by high-order harmonics, which is the basis for the high accuracy of on-line core power reconstruction. Therefore, on the basis of accurately calculating the current high-order harmonics in real time, the preset matrix equation is solved using the least squares method to generate the corresponding equation coefficients, and the equation coefficients and the high-order harmonic matrix are input into the preset core power determination algorithm, and a higher-precision core power distribution can be reconstructed.

[0168] Exemplarily, the preset core power determination algorithm is specifically as follows:

[0169] P fitted = Mx

[0170] P fittedIt is the core power distribution obtained by reconstruction, and the meanings of other parameters are the same as those of the aforementioned algorithm parameters.

[0171] The core power monitoring method provided in this embodiment can calculate the current higher-order harmonics corresponding to the target reactor in real time based on a preset multi-group diffusion equation, preset constants, etc. Compared with the method of pre-establishing a harmonic database covering a large number of operating conditions, it occupies less memory, can better reflect the actual conditions, and at the same time, the determined current higher-order harmonics have higher accuracy and precision. In addition, since the higher-order harmonics are theoretically complete, the power distribution under any condition can be expanded by the higher-order harmonics, so that the accuracy of the core power distribution reconstructed based on the current higher-order harmonics and the preset response matrix of the off-core detector is higher.

[0172] Secondly, this method gets rid of the limitations of the core type, detector distribution, and preset conditions of the database, and can calculate the higher-order harmonics under any condition in real time. By combining the nuclear measurement signals collected by the off-core detector with the reactor operating status information, the online reconstruction of the core power can be quickly realized. This method not only improves the flexibility and accuracy of power monitoring, but also greatly reduces the dependence on the prefabricated database, providing a more efficient solution for the online monitoring system of the micro nuclear reactor.

[0173] To better understand the core power monitoring method provided in the embodiments of the present application, the following will be described in conjunction with a specific application implementation manner.

[0174] A typical gas-cooled microreactor core model is as Figure 3 shown. The core consists of hexagonal fuel assemblies, control rod assemblies, and a reflector with the same geometric structure in the active zone. Outside the core, there are boron carbide bricks, a basket, a pressure vessel, a shielding layer, a carriage frame, etc. The off-core neutron detectors (i.e., off-core detectors) are arranged outside the steel shielding layer, with 3 positions arranged asymmetrically in the radial direction, and there are 4 groups of detectors axially at each position, that is, there are a total of 12 groups of off-core detectors. There are 30 fuel assembly columns in the radial direction of the core, and each column of assemblies has 3 layers of fuel assemblies axially, so there are 90 fuel nodules in the whole reactor. There are two sets of control rods arranged. The first set is located outside the active zone and has 6 groups of control rods, which are used for core operation control, cold shutdown, hot shutdown, emergency shutdown, etc. The second set is located at the center of the core and has 1 group of control rods, which is used as a backup shutdown means and only realizes the hot shutdown of the core when the first set of control rods cannot shut down the reactor.

[0175] Using the method of the embodiments of the present application to carry out online monitoring and analysis for a typical gas-cooled microreactor core, according to the method of online calculating higher-order harmonics, the specific implementation steps are as follows:

[0176] Specifically, before the microreactor starts running:

[0177] (1) Establish an accurate three-dimensional core model

[0178] According to the design scheme of a typical gas-cooled micro reactor, a real and detailed three-dimensional model of the reactor core is established using a general Monte Carlo program. The model includes the dispersed distribution of TRISO fuel particles (three-layer isotropic coated particles) in the fuel pellets, the fuel rod structure, the fuel assembly and its internal blind sections, end plugs and other structures, the arrangement of the in-core fuel assemblies, control rod assemblies, and reflector, and the structures outside the reactor such as boron carbide bricks, hanging baskets, pressure vessels, shielding layers, out-of-core detectors, and carriage frames. When modeling, the settings are made according to the actual sizes, materials, and design schemes of each component.

[0179] (2) Construct the out-of-core detector response matrix

[0180] Calculate the response matrix for all power statistical nodes (i.e., fuel nodes) and all detector positions, and construct the out-of-core detector response matrix, which includes the response matrix of 90 nodes and 12 detector positions. The Monte Carlo forward calculation method is adopted:

[0181] 1) Statistically analyze the fission neutron source strength distribution at each fuel node position in the reactor core.

[0182] 2) Set the source term according to the fission neutron source strength, use the Monte Carlo program to calculate in the fixed source mode, solve the neutron deep penetration problem through the function of setting the importance of lattice cells, and statistically analyze the spatial response matrix of each out-of-core detector.

[0183] 3) Construct a 12×90 node-level response matrix.

[0184] After obtaining the out-of-core detector response matrix, the following process is required for online core power monitoring:

[0185] (1) Collect reactor status information and out-of-core detector signals

[0186] Collect the pre-operation instructions of the operator or intelligent control system to obtain reactor status information such as control rod positions, temperature, burnup, depth, etc. Collect 12 groups of non-repeated nuclear measurement signals of the out-of-core detector under unknown working conditions. For the convenience of demonstration, the working condition with the control rod position close to 80 cm is used for the next monitoring. Among them, the 12 groups of nuclear measurement signals are shown in Table 1.

[0187] Table 1 Detector signal values under a certain working condition

[0188] Detector Number Detector Count 1 88.177 2 87.361 3 87.255 4 87.543 5 87.852 6 87.244 7 87.402 8 87.451 9 87.841 10 86.571 11 86.362 12 86.576

[0189] (2) Online calculate the higher-order harmonics of the predicted working condition (i.e., the current higher-order harmonics)

[0190] Based on the reactor status information with the control rod position close to 80 cm collected in the previous step, the higher-order harmonics can be calculated online through the diffusion program or calculated through each algorithm in the foregoing embodiments.Figure 4 shows the 0-12th order eigenvalues of a gas-cooled micro reactor (GMR) under a certain operating condition. As Figure 4 shown, the eigenvalues in the figure generally show a downward trend as the order increases. However, there are some intervals where the eigenvalues do not change, because the eigenvalues of two adjacent orders are conjugate. Therefore, the high-order harmonics represented by the white circles in the figure are selected for subsequent use. Figure 5 shows the 0-12th order harmonics under a certain operating condition. A small number (taking 3 as an example) of symmetric harmonics can be selected, and the selected harmonic group is multiplied by the response matrix of the out-of-core detector for the next step of processing.

[0191] (3) Combining the response matrix of the out-of-core detector, the nodal core power distribution is reconstructed in real time using the least squares method

[0192] Based on the product of the high-order harmonics obtained in the previous step and the response matrix of the out-of-core detector, combined with the out-of-core detector signals collected in the first step, the nodal core power distribution is reconstructed in real time using the least squares method. Specifically, it is to solve the matrix equation:

[0193] DMx = R

[0194] In the formula, M is a matrix composed of 3 high-order harmonics, x is the expansion coefficient vector (i.e., the equation coefficient), R is the signal values of 12 out-of-core detectors collected, and D is the corresponding out-of-core detector response matrix.

[0195] After solving the coefficient x, the nodal core power distribution can be obtained through the following formula:

[0196] P fitted = Mx

[0197] P fitted is the reconstructed nodal core power distribution (from bottom to top, a total of 3 layers).

[0198] Finally, after determining the core power distribution, it can be compared with the true power distribution. For example, Figure 6 shows the true power distribution when the control rod position is close to 80 cm (the accurate calculation result of the Monte Carlo program), Figure 7 shows the power distribution reconstructed in this embodiment by combining the high-order harmonics calculated online and the detector counts in Table 1. Based on Figure 6 and Figure 7 it can be seen that the true power distribution and the power distribution reconstructed in this embodiment are very close. Further, as Figure 8 shown, Figure 8 shows the relative deviation between the reconstructed power and the true power. It can be seen from the figure that the maximum error of the nodal power is -1.4%, meeting the requirement that the accuracy error of online monitoring is within ±5%.

[0199] The core power monitoring method of this embodiment can be used for remote real-time monitoring and intelligent control of a micro nuclear energy system. This method adopts the overall idea of online calculation of high-order harmonics, and pre-obtains the response matrix of out-of-core detectors based on an accurate three-dimensional core model and a general and accurate Monte Carlo nuclear design program. During online power monitoring, first, the reactor status information and out-of-core detector signals are collected, the high-order harmonics are calculated online, combined with the out-of-core detector response matrix, and the least squares method is used to reconstruct the nodal-level core power distribution in real time. Thus, the purpose of online monitoring of the core power can be quickly and accurately achieved only relying on the nuclear measurement signals of a small number of out-of-core detectors. At the same time, without relying on a large number of prefabricated databases for various working conditions, it has high fitting accuracy and consumes less local computing resources, and can accurately and quickly calculate the in-core power distribution.

[0200] Embodiment 3

[0201] As Figure 9 shown, the core power monitoring device 400 provided by the embodiment of the present application may include:

[0202] An acquisition module 401, configured to acquire the current status information of the target reactor and the current nuclear measurement signals of multiple groups of out-of-core detectors. The target reactor corresponds to the out-of-core detectors.

[0203] A first determination module 402, configured to determine the current high-order harmonics corresponding to the target reactor according to the current status information.

[0204] A second determination module 403, configured to determine the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset out-of-core detector response matrix, and the current nuclear measurement signals. The target high-order harmonics are the high-order harmonics selected from the current high-order harmonics. The preset out-of-core detector response matrix corresponds to the out-of-core detectors. The preset number is less than the number of groups of out-of-core detectors.

[0205] In some embodiments, the first determination module 402 is specifically configured to:

[0206] Determine the corresponding preset constant according to the current status information. The preset constant is related to the calculation of the current high-order harmonics. Input the preset constant into the preset multi-group diffusion equation. Solve the preset multi-group diffusion equation based on the outer iteration solution method to generate the corresponding solution result. Determine the current high-order harmonics according to the solution result and the preset constant.

[0207] In some embodiments, when the first determination module 402 determines the current high-order harmonics according to the solution result and the preset constant, it is specifically configured to:

[0208] Input the solution result and preset constants into a preset high-order flux algorithm and a preset high-order adjoint flux algorithm. Solve the preset high-order flux algorithm and the preset high-order adjoint flux algorithm based on an iterative solution method to generate corresponding high-order fluxes. Input the high-order fluxes into a preset high-order fission reaction rate algorithm to determine the corresponding high-order fission reaction rate based on the preset high-order fission reaction rate algorithm. Determine the current high-order harmonics according to the high-order fission reaction rate.

[0209] In some embodiments, the second determination module 403 is specifically configured to:

[0210] Determine the product between the high-order harmonic matrix and the preset out-of-core detector response matrix to generate a corresponding product result. The high-order harmonic matrix is constructed based on a preset number of target high-order harmonics. Determine the core power distribution according to the product result and the current nuclear measurement signal.

[0211] In some embodiments, when the second determination module 403 determines the core power distribution according to the product result and the current nuclear measurement signal, it is specifically configured to:

[0212] Input the product result and the current nuclear measurement signal into a preset matrix equation. Solve the preset matrix equation using the least squares method to generate corresponding equation coefficients. Input the equation coefficients and the high-order harmonic matrix into a preset core power determination algorithm to generate the core power distribution based on the preset core power determination algorithm.

[0213] In some embodiments, the core power monitoring device 400 further includes:

[0214] A screening module, configured to screen a preset number of symmetric high-order harmonics from all current high-order harmonics. Determine the symmetric high-order harmonics as the target high-order harmonics.

[0215] In some embodiments, the preset number is greater than or equal to three.

[0216] The screening module is further configured to:

[0217] Determine the total number of symmetric high-order harmonics among all current high-order harmonics. If the total number is greater than or equal to four, determine the preset number as three or four. If the total number is equal to three, determine the preset number as three.

[0218] In some embodiments, the core power monitoring device 400 further includes:

[0219] A construction module, configured to construct a reactor model corresponding to the target reactor using a Monte Carlo nuclear design program. Calculate the out-of-core detector response matrix between each fuel assembly and the out-of-core detector in the reactor model using the Monte Carlo nuclear design program.

[0220] The core power monitoring device provided by the embodiments of the present application has the beneficial effects and implementation manners of the core power monitoring methods provided by Embodiment 1 and Embodiment 2 of the present application. Specifically, reference can be made to the specific descriptions of the core power monitoring methods in the above-mentioned Embodiment 1 and Embodiment 2, and details will not be repeated in this embodiment.

[0221] Embodiment 4

[0222] The embodiments of the present application further provide an electronic device, which includes:

[0223] A memory and a processor.

[0224] The memory stores computer-executable instructions.

[0225] The processor executes the computer-executable instructions stored in the memory to implement the core power monitoring methods as in Embodiment 1 and Embodiment 2.

[0226] The electronic device provided by the embodiments of the present application has the beneficial effects and implementation manners of the core power monitoring methods provided by Embodiment 1 and Embodiment 2 of the present application. Specifically, reference can be made to the specific descriptions of the core power monitoring methods in the above-mentioned Embodiment 1 and Embodiment 2, and details will not be repeated in this embodiment.

[0227] Embodiment 5

[0228] The embodiments of the present application further provide a monitoring system, which includes:

[0229] The electronic device in Embodiment 4. The electronic device is used to implement the core power monitoring methods in Embodiment 1 and Embodiment 2.

[0230] The monitoring system provided by the embodiments of the present application can also be a control system in practical applications, which has the beneficial effects and implementation manners of the core power monitoring methods provided by Embodiment 1 and Embodiment 2 of the present application. Specifically, reference can be made to the specific descriptions of the core power monitoring methods in the above-mentioned Embodiment 1 and Embodiment 2, and details will not be repeated in this embodiment.

[0231] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present application. However, the present application is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present application, and these modifications and improvements are also regarded as the protection scope of the present application.

Claims

1. A method for monitoring core power, characterized in that, Including: Obtaining the current state information of a target reactor and the current nuclear measurement signals of multiple sets of off-reactor detectors; The target reactor corresponds to the off-reactor detectors; Determining the current high-order harmonics corresponding to the target reactor according to the current state information; Determining the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset off-reactor detector response matrix, and the current nuclear measurement signals; the target high-order harmonics are the high-order harmonics selected from the current high-order harmonics; the preset off-reactor detector response matrix corresponds to the off-reactor detectors; the preset number is less than the number of groups of the off-reactor detectors.

2. The method according to claim 1, wherein The determining the current high-order harmonics corresponding to the target reactor according to the current state information includes: Determining a corresponding preset constant according to the current state information; the preset constant is related to calculating the current high-order harmonics; Inputting the preset constant into a preset multi-group diffusion equation; Solving the preset multi-group diffusion equation based on an outer iteration solution method to generate a corresponding solution result; Determining the current high-order harmonics according to the solution result and the preset constant.

3. The method according to claim 2, wherein The determining the current high-order harmonics according to the solution result and the preset constant includes: Inputting the solution result and the preset constant into a preset high-order flux algorithm and a preset high-order adjoint flux algorithm; Solving the preset high-order flux algorithm and the preset high-order adjoint flux algorithm based on an iteration solution method to generate a corresponding high-order flux; Inputting the high-order flux into a preset high-order fission reaction rate algorithm to determine a corresponding high-order fission reaction rate based on the preset high-order fission reaction rate algorithm; Determining the current high-order harmonics according to the high-order fission reaction rate.

4. The method according to claim 1, wherein The determining the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset off-reactor detector response matrix, and the current nuclear measurement signals includes: Determining the product between the high-order harmonic matrix and the preset off-reactor detector response matrix to generate a corresponding product result; the high-order harmonic matrix is constructed based on a preset number of target high-order harmonics; Determining the core power distribution according to the product result and the current nuclear measurement signals.

5. The method according to claim 4, characterized in that, The determining the core power distribution according to the product result and the current nuclear measurement signals includes: Inputting the product result and the current nuclear measurement signals into a preset matrix equation; Solving the preset matrix equation by using the least squares method to generate corresponding equation coefficients; Inputting the equation coefficients and the high-order harmonic matrix into a preset core power determination algorithm to generate the core power distribution based on the preset core power determination algorithm.

6. The method according to any one of claims 1 to 5, characterized in that, Before the determining the core power distribution corresponding to the target reactor according to a preset number of target high-order harmonics, a preset off-reactor detector response matrix, and the current nuclear measurement signals, the method further includes: Screening a preset number of symmetric high-order harmonics from all the current high-order harmonics; Determining the symmetric high-order harmonics as the target high-order harmonics.

7. The method according to claim 6, characterized in that The preset number is greater than or equal to three; Before the screening a preset number of symmetric high-order harmonics from all the current high-order harmonics, the method further includes: Determine the total number of symmetric higher-order harmonics among all current higher-order harmonics; If the total number is greater than or equal to four, determine the preset number to be three or four; If the total number is equal to three, determine the preset number to be three.

8. The method according to any one of claims 1 to 5, characterized in that, Before determining the core power distribution corresponding to the target reactor according to the target higher-order harmonics of the preset number, the preset out-of-core detector response matrix, and the current nuclear measurement signal, the method further includes: Construct a reactor model corresponding to the target reactor using a Monte Carlo nuclear design program; Calculate the out-of-core detector response matrix between each fuel assembly and the out-of-core detector in the reactor model using a Monte Carlo nuclear design program.

9. A core power monitoring device, characterized in that, Include: An acquisition module for acquiring the current state information of the target reactor and the current nuclear measurement signals of multiple groups of out-of-core detectors; The target reactor corresponds to the out-of-core detector; A first determination module for determining the current higher-order harmonics corresponding to the target reactor according to the current state information; A second determination module for determining the core power distribution corresponding to the target reactor according to the target higher-order harmonics of the preset number, the preset out-of-core detector response matrix, and the current nuclear measurement signal; the target higher-order harmonics are the higher-order harmonics selected from the current higher-order harmonics; the preset out-of-core detector response matrix corresponds to the out-of-core detector; the preset number is less than the number of groups of the out-of-core detectors.

10. An electronic device, characterized in that, Include: A memory and a processor; The memory stores computer execution instructions; The processor executes the computer execution instructions stored in the memory to implement the core power monitoring method according to any one of claims 1 to 8.

11. A monitoring system, characterized in that, Include: The electronic device according to claim 10; the electronic device is used to implement the core power monitoring method according to any one of claims 1 to 8.

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