Nuclear reactor core operation analysis method, system, device and computer readable medium

Abstract

The present invention provides a nuclear reactor core operation analysis method and system, which includes: establishing a solid core geometric model; meshing the geometric model and setting physical parameters and boundary conditions of the solid core; establishing a neutron nuclear database, performing neutron physics calculation based on the database and the solid core geometric model to obtain the power size and power distribution results of the solid core; performing thermal analysis calculation based on the solid core power size and power distribution results to obtain the temperature distribution results of the solid core; performing mechanical analysis calculation based on the core temperature distribution results of the solid core to obtain deformation geometry calculation results; iteratively performing neutron physics calculation based on the core temperature distribution results of the solid core and the deformation geometry calculation results until the results of the iterative calculation meet specific convergence conditions; and obtaining neutron physics parameters, temperature distribution parameters and stress-strain distribution parameters of the fixed core under steady-state conditions based on the results of the iterative calculation.

Description

Technical Field

[0001] The present invention mainly relates to the field of nuclear reactors, and in particular to a method, system, device and computer-readable medium for analyzing the operation of a nuclear reactor core. Background Art

[0002] The physical, thermal, and mechanical properties of nuclear reactors are complex, interconnected systems. The high operating temperature of solid-state cores leads to significant thermal expansion effects in materials, resulting in large stress deformations. Furthermore, the varying temperatures of the materials at different locations create dynamic geometric boundaries within the core, altering the neutron distribution and mechanical properties of the materials, thereby affecting core neutron physics processes. Based on deterministic physical models, steady-state multi-physics coupled numerical simulations of solid-state cores reveal the inter-coupling mechanisms between neutron physics, core heat transfer, and matrix deformation, a crucial approach for studying solid-state core characteristics.

[0003] With the continuous improvement of computer hardware computing power, advanced visual modeling, multi-physics, multi-scale, and refined simulations have experienced rapid development. Technical challenges need to be addressed, including modeling and calculating key multi-physics coupling processes such as solid-state core neutron transport, heat and mass transfer, and matrix expansion. Understanding the influence of key parameters in each deterministic physics model on the physical process and analyzing the coupling phenomena and mechanisms between various physical fields are key challenges. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a nuclear reactor core operation analysis method and system, which reduces the coupling complexity and improves the feasibility of multi-physics coupling analysis of solid-state cores by performing multi-physics coupling calculations on solid-state cores.

[0005] To solve the above technical problems, the present invention provides a nuclear reactor core operation analysis method, comprising: establishing a solid core geometric model; meshing the geometric model and setting physical properties and boundary conditions of the solid core; establishing a neutron core database, performing neutron physics calculations based on the neutron core database and the meshed solid core geometric model to obtain the power size and power distribution results of the solid core; performing thermal analysis calculations based on the solid core power size and power distribution results to obtain the temperature distribution results of the solid core; performing mechanical analysis calculations based on the core temperature distribution results of the solid core to obtain deformation geometry calculation results; updating neutron physics calculation input data based on the core temperature distribution results of the solid core and the deformation geometry calculation results, and iteratively performing neutron physics calculations until the results of the iterative calculations meet specific convergence conditions; based on the results of the iterative calculations, obtaining neutron physics parameters, temperature distribution parameters and stress-strain distribution parameters of the fixed core under steady-state conditions.

[0006] In one embodiment of the present invention, the nuclear reactor core operation analysis method also includes: using the parameter results corresponding to the steady-state situation as the initial value of the transient calculation; setting the initial time, calculation time step and transient simulation time of the transient calculation; when the total transient calculation running time is less than or equal to the set transient simulation time, iterating the second stage neutron physics calculation until the total transient calculation running time is greater than the set transient simulation time; based on the iterative results of the second stage neutron physics calculation, obtaining the neutron physics parameters, temperature distribution parameters and stress and strain distribution parameters of the fixed core under transient conditions.

[0007] In one embodiment of the present invention, the physical property parameters of the solid core include the initial temperature of the core material, the initial maximum temperature of the calculation domain and the initial effective proliferation coefficient of the core.

[0008] In one embodiment of the present invention, the power size and power distribution results of the solid-state core include the power size and power distribution results of the fuel rod cells.

[0009] In one embodiment of the present invention, based on the power size and power distribution results of the solid-state core, a thermal analysis calculation is performed to obtain the temperature distribution results of the solid-state core, including: using the power size and power distribution results of the fuel rod grid element as input data for the thermal analysis calculation; based on the input data, performing thermal analysis calculation through grid mapping and data transfer operations.

[0010] In one embodiment of the present invention, the temperature distribution result of the solid core includes the average temperature of the fuel rod grid unit corresponding to the fuel rod grid cell and the average temperature of the nuclear reactor matrix grid cell.

[0011] In one embodiment of the present invention, a mechanical analysis calculation is performed based on the core temperature distribution results of the solid core to obtain the deformation geometry calculation results, including: the average temperature of the fuel rod grid unit corresponding to the fuel rod grid element and the average temperature of the nuclear reactor matrix grid element are subjected to mechanical analysis calculation through grid mapping and data transfer operations to obtain the stress, strain and deformation calculation results of the fuel rod and the nuclear reactor matrix, as well as the average deformation calculation results of the fuel rod grid corresponding to the fuel rod grid element.

[0012] In one embodiment of the present invention, based on the results of the core temperature distribution of the solid-state core and the deformation geometry calculation results, the neutron physics calculation input data is updated, including: based on the average temperature of the fuel rod grid unit corresponding to the fuel rod grid element, the average temperature of the nuclear reactor matrix grid element and the average deformation calculation results of the fuel rod grid corresponding to the fuel rod grid element, the core material temperature and geometric parameters of the corresponding grid element in the neutron physics calculation are updated.

[0013] In one embodiment of the present invention, the grid mapping operation includes performing grid mapping on the grid using a linear interpolation algorithm.

[0014] In one embodiment of the present invention, the data transfer operation includes: constructing a continuous interpolation function based on discrete data; integrating the continuous interpolation function within the unit volume of the neutron physics calculation to obtain the unit internal average value of the required data; wherein the unit is obtained based on the grid division operation.

[0015] In one embodiment of the present invention, based on the neutron physics calculation, the effective proliferation coefficient of the core is also obtained.

[0016] In one embodiment of the present invention, the specific convergence condition includes: the difference between the core effective proliferation coefficient and the core initial effective proliferation coefficient is less than a first parameter threshold, and the calculation domain maximum temperature detection value is less than a second parameter threshold.

[0017] In one embodiment of the present invention, the establishment of a neutron nuclear database includes: creating a basic fine group cross-section database; performing resonant self-screening calculations based on a solid core geometric model to obtain an effective self-screening cross-section suitable for neutron physics calculations; obtaining a fine group cross-section database suitable for nuclear reactor multi-physics field coupling calculations by combining the basic fine group cross-section database and the effective self-screening cross-section data; and merging the fine group cross-section database to obtain a wide group cross-section database suitable for neutron physics calculations.

[0018] The present invention also provides a nuclear reactor core operation analysis system, comprising: a core geometry modeling module, a grid division module, an initialization setting module, a physical property module, a calculation module and a coupling calculation module; the calculation module comprises a neutron physics model calculation module, a thermal model calculation module and a mechanical mechanics model calculation module; the coupling calculation module can be divided into a data exchange module and an iterative convergence control module; the core geometry modeling module is used to establish a solid-state core geometry model; the grid division module is used to grid the geometric model; the initialization setting module is used to set the boundary conditions of the solid-state core and establish a neutron nuclear database; the physical property module is used to set the physical property parameters of the solid-state core; the neutron physics model calculation module is used to implement the neutron physics calculation process; the thermal model calculation module is used to implement the thermal analysis calculation process; the mechanical mechanics model calculation module is used to implement the mechanical analysis calculation process; the data exchange module is used for the data exchange operation of the model; and the iterative convergence control module is used to perform convergence control operations on the iterative calculation process.

[0019] In one embodiment of the present invention, the physical property parameters include thermal physical property parameters and structural physical property parameters of the solid core.

[0020] In one embodiment of the present invention, the neutron physics model calculation module includes a component calculation module and a core calculation module; the component calculation module is configured to: calculate the ultrafine group cross-section information of each material zone in the core through point cross-section information; solve the neutron flux density distribution by solving the uniform problem slowing down equation or the collision probability method; merge the ultrafine group cross-sections into groups and zones; the core calculation module is configured to: perform angle discrete calculations through the discrete ordinate method; and perform spatial discrete calculations through the node method of arbitrary triangular grids.

[0021] The present invention also provides a nuclear reactor core operation analysis device, comprising:

[0022] a memory for storing instructions executable by the processor; and

[0023] A processor is configured to execute the instructions to implement the method as described in any of the preceding items.

[0024] The present invention also provides a computer-readable medium storing computer program code, wherein the computer program code implements the method as described in any one of the preceding items when executed by a processor.

[0025] Compared with the existing technology, the present invention has the following advantages: the application scheme comprehensively considers the nuclear physics, thermal and mechanical parameter performance of the solid-state core, improves the effectiveness and feasibility of the coupling calculation process corresponding to the solid-state core analysis, and provides a solid foundation for the multi-physical field coupling analysis and application of the solid-state core. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are provided to provide a further understanding of the present application. They are included in and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0027] In the attached figure:

[0028] Figure 1 It is a flow chart corresponding to the nuclear reactor core operation analysis method according to an embodiment of the present application.

[0029] Figure 2 It is a schematic diagram of the composition of a nuclear reactor core operation analysis system according to an embodiment of the present application.

[0030] Figure 3 Schematic diagram of the mapping method between discrete temperature data and model grid according to an embodiment of the present application.

[0031] Figure 4 It is a schematic diagram of the composition of a nuclear reactor core operation analysis device according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0033] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0034] Flowcharts are used in this application to illustrate the operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0035] Embodiments of the present application describe a nuclear reactor core operation analysis method, system, apparatus, and computer-readable medium.

[0036] Figure 1 It is a flow chart corresponding to the nuclear reactor core operation analysis method according to an embodiment of the present application. Figure 1 It can also be seen as a flow chart corresponding to the multi-physics coupling analysis and calculation process of the solid-state core based on the deterministic physical model.

[0037] In some embodiments, a nuclear reactor core operation analysis method includes: establishing a solid-state core geometric model; meshing the geometric model and setting physical properties and boundary conditions of the solid-state core; establishing a neutron nuclear database, performing neutron physics calculations based on the neutron nuclear database and the meshed solid-state core geometric model to obtain the power size and power distribution results of the solid-state core; performing thermal analysis calculations based on the solid-state core power size and power distribution results to obtain the temperature distribution results of the solid-state core; performing mechanical analysis calculations based on the core temperature distribution results of the solid-state core to obtain deformation geometry calculation results; updating neutron physics calculation input data based on the core temperature distribution results of the solid-state core and the deformation geometry calculation results, and iteratively performing neutron physics calculations until the results of the iterative calculations meet specific convergence conditions; based on the results of the iterative calculations, obtaining neutron physics parameters, temperature distribution parameters and stress-strain distribution parameters of the fixed core under steady-state conditions.

[0038] refer to Figure 1 Regarding the nuclear reactor core operation analysis method of the present application, specifically, the first is the pre-processing part, which includes establishing a solid core geometric model, meshing the geometric model, and setting up the physical parameters and boundary conditions of the solid core.

[0039] Then comes the initialization setup part. First, a neutron nuclear database suitable for calculation based on deterministic methods is established. Then, based on this neutron nuclear database, a deterministic calculation program is used to perform neutron physics calculations on the solid-state core model, and then the power size and power distribution of the solid-state core are obtained, providing initial input for subsequent calculation programs.

[0040] Next, based on the initial power distribution of the solid-state core, thermal analysis calculations are carried out to obtain the temperature distribution of the solid-state core, and mechanical analysis calculations are carried out based on the results of the core temperature distribution to perform deformation geometry calculations. The solved solid-state core material temperature and deformation geometry results are then updated together into the neutron physics solution input data to correct the solid-state core geometry, material parameters and nuclear data.

[0041] Then, the neutron physics calculation is carried out again and the next iteration is entered until the iterative results meet the convergence conditions. In this way, the neutron parameters, temperature distribution and stress-strain distribution of the solid-state core can be obtained under steady-state conditions considering multi-physics coupling calculations.

[0042] In some embodiments, the nuclear reactor core operation analysis method also includes: using the parameter results corresponding to the steady-state situation as the initial value of the transient calculation; setting the initial time, calculation time step and transient simulation time of the transient calculation; when the total transient calculation running time is less than or equal to the set transient simulation time, iterating the second stage neutron physics calculation until the total transient calculation running time is greater than the set transient simulation time; based on the iterative results of the second stage neutron physics calculation, obtaining the neutron physics parameters, temperature distribution parameters and stress and strain distribution parameters of the fixed core under transient conditions.

[0043] Specifically, the steady-state calculation results are used as the initial values ​​for the transient calculation, and this time is set as the initial time, and the transient calculation time step and transient simulation time are set.

[0044] When the total running time of the transient calculation is less than the set transient simulation time, the neutron physics calculation is carried out again and the next iteration is entered. The total running time of the transient calculation is increased by one time step each time the transient calculation is repeated until the total running time of the transient calculation is greater than the set transient simulation time. Then the calculation results under the transient condition can be obtained.

[0045] In the technical solution of the present application, the multi-physical field coupling calculation process of the solid-state core involves a grid mapping process between different physical fields, including data mapping and geometric mapping of the physical fields.

[0046] Physical field data mapping primarily involves mapping the power distribution obtained from neutron physics analysis to thermal analysis as an internal heat source; loading the core temperature distribution obtained from thermal analysis into the statics analysis module and mapping it to the neutron physics analysis module. Geometric mapping primarily involves mapping the core geometric deformation obtained from statics analysis to the physical boundaries used in neutron physics analysis.

[0047] The grid is the data carrier for different physical fields. Therefore, the data mapping of physical fields between neutron physics calculations, thermal analysis calculations, and statics calculations mainly involves the grid mapping of the two physical fields.

[0048] Cells serve as the fundamental geometric building blocks in deterministic methods. Traditionally, cells are defined by Boolean combinations of spatial regions, a technique used in constructive solid geometry (CSG) to construct geometric entities. Data from various physical fields must be exchanged between the neutron physics program and the grid.

[0049] In neutron physics programs, the resolution of material, temperature, and density information is tracked only by the element; in finite element programs, the temperature field is relatively high resolution. In some cases, interpolation methods can be used to map the finely resolved temperature to the coarsely resolved element-based geometric description in the neutron physics program, a technique known as mesh mapping.

[0050] Figure 3 This is a schematic diagram of the mapping method of discrete temperature data and model grid in an embodiment of the present application. The discrete temperature data calculated by the finite element program is transferred to the grid mapping method of the neutron physics calculation program as shown in FIG. Figure 3 shown. Figure 3 A cell with origin O(x0,y0,z0) and discrete temperature data T obtained from the finite element program data set are shown in i , where the red points represent data points inside the cell and the blue points are outside the cell.

[0051] A piecewise continuous linear interpolation function ψ is constructed on the discrete temperature data. This function is integrated over the entire unit volume to obtain the average temperature inside the unit, as shown in the following equation. This realizes the data mapping from the temperature field obtained by thermal analysis calculation to the neutron physics calculation.

[0052]

[0053] Where: T - temperature; V i ——Procedural grid volume; T i ——Temperature value in the program grid; r——radial unit, z——axial unit.

[0054] The following combination Figure 1 The flow chart shown in the figure further elaborates on this scheme:

[0055] Step 1: Pre-processing setup: First, for the solid-state core structure, a core geometry model is constructed using modeling software to generate input files for neutron physics calculations. The geometry model is then meshed using meshing tools.

[0056] The meshed model is then imported into the solver of the computational program to perform initial solution settings, including the initial core material temperature, the initial maximum temperature of the computational domain, the initial effective core multiplication coefficient, the initial boundary conditions, and the program's monitor settings.

[0057] Step 2: Start the calculation. The main program controls the execution of the core neutron physics calculations and generates the calculation output file 1. Specifically, a basic fine cluster cross-section database is first created. Then, based on the solid-state core model, a resonant self-screening calculation is performed to obtain an effective self-screening cross-section suitable for the calculation. By combining the basic fine cluster cross-section database and the effective self-screening cross-section data, a fine cluster cross-section database suitable for multi-physics field coupling calculations is obtained. Finally, these two data are merged to obtain a wide cluster cross-section database suitable for the calculation, and then the neutron physics calculations are carried out.

[0058] Output file 1 contains the calculation results of the effective proliferation coefficient of the core and the power size and distribution of the fuel rod grid elements.

[0059] Step 3: First, parse the output file 1 in step 2, use the power size and distribution of the fuel rod grid elements in the output file 1 as the input of the thermal analysis calculation, and use the grid mapping and data transfer method to perform thermal analysis calculation.

[0060] When the monitor set in step 1 detects that the change in the maximum temperature of the computational domain is less than the set temperature threshold, the thermal analysis calculation is completed, and the average temperature of the fuel rod grid cell corresponding to the fuel rod grid cell and the average temperature of the entire matrix are output to output file 2. The set temperature threshold can be, for example, 500K, 600K, 800K, or 900K, where K represents the temperature unit, the calvin.

[0061] Step 4: The main program controls the multi-physics field coupling analysis program to transfer the temperature distribution of the fuel rods and the matrix in the output file 2 in step 3 (i.e., the average temperature of the fuel rod grid unit corresponding to the fuel rod grid element and the average temperature value of the entire matrix) to the grid for mechanical analysis calculation by using grid mapping and data transfer, and then perform mechanical calculations to obtain the stress, strain, and deformation of the fuel rods and the matrix, and output the average deformation of the fuel rod grid corresponding to each fuel rod grid element to output file 3.

[0062] Step 5: The main program uses the average fuel rod cell temperature, average matrix cell temperature, and average fuel rod cell deformation output from Steps 3 and 4 to update the core material temperature and geometric parameters of the corresponding fuel rod cells in the input file of the neutron transport program based on the deterministic calculation method. Geometric parameters include, for example, geometric diameter.

[0063] Step 6: When the difference between the effective core multiplication coefficient output in step 2 and the initially set effective core multiplication coefficient is less than the first parameter threshold, and the maximum temperature change of the calculation domain detected by the monitor in step 3 is less than the second parameter threshold, the program coupling calculation is considered to have converged, the calculation is completed, and the calculation results under steady state are output. The first parameter threshold is, for example, 10 -5 , 10 -6 , 10 -7 or 10-8 The second parameter threshold is, for example, a value such as 500K, 600K, 800K, or 900K, where K represents the temperature unit, Calvin.

[0064] When the two convergence conditions are not met, the finite multiplication coefficient is instructed to be equal to the finite multiplication coefficient output in step 2, and the maximum temperature of the calculation domain is instructed to be equal to the maximum temperature of the calculation domain in step 3. Steps 2 to 6 are repeated until the calculation converges.

[0065] Step 7: Instruct the steady-state calculation results output in step 6 to be used as the initial value for transient calculation, and instruct this time to be the initial time, set the transient calculation time step and transient simulation time.

[0066] Step 8: Start transient calculation. When the total transient calculation running time is less than or equal to the transient simulation time set in step 7, repeat steps 2 to 5, and increase the total transient calculation running time by one time step set in step 7 each time the transient calculation is repeated until the total transient calculation running time is greater than the transient simulation time set in step 7. Then, output the calculation results under transient conditions.

[0067] The present application also provides a nuclear reactor core operation analysis system. Figure 2 It is a schematic diagram of the composition of a nuclear reactor core operation analysis system according to an embodiment of the present application.

[0068] In some embodiments, a nuclear reactor core operation analysis system includes: a core geometry modeling module, a meshing module, an initialization setting module, a physical property module, a calculation module and a coupling calculation module; the calculation module includes a neutron physics model calculation module, a thermal model calculation module and a mechanical mechanics model calculation module; the coupling calculation module can be divided into a data exchange module and an iterative convergence control module; the core geometry modeling module is used to establish a solid-state core geometry model; the meshing module is used to mesh the geometry model; the initialization setting module is used to set the boundary conditions of the solid-state core and establish a neutron nuclear database; the physical property module is used to set the physical property parameters of the solid-state core; the neutron physics model calculation module is used to implement the neutron physics calculation process; the thermal model calculation module is used to implement the thermal analysis calculation process; the mechanical mechanics model calculation module is used to implement the mechanical analysis calculation process; the data exchange module is used for the data exchange operation of the model; the iterative convergence control module is used to perform convergence control operations on the iterative calculation process.

[0069] Specifically, refer to Figure 2 ,The nuclear reactor core operation analysis system can be divided into ,input and output modules, pre- and post-processing modules, calculation modules, ,physical property modules and coupling calculation modules.

[0070] The input and output module can be divided into the input condition reading module, program information output module, logic control module and termination module. The input condition reading module is used to check whether the input file is incorrect and confirm the total number of conditions for batch calculation.

[0071] The program information output module outputs program information, including name, time, and version. The logic control module selects the calculation type based on the input file. The termination module reports an error and terminates the program if a calculation error occurs. The pre- and post-processing modules are divided into the core geometry modeling module, the meshing module, the initialization settings module, and the result output module.

[0072] The core geometry modeling module is used to implement detailed modeling of the core geometry. The meshing module is used to mesh the core geometry. The initialization module is used to set computational boundary conditions and perform initial configuration of the computational software. The result output module is used to output the program's computational results and display the result renderings.

[0073] The calculation modules can be divided into, for example, a neutron physics calculation module, a thermal calculation module, and a mechanical mechanics calculation module. The neutron physics calculation module is used to calculate core neutron physics parameters and power distribution. The thermal calculation module is used to calculate the core temperature field. The mechanical mechanics calculation module is used to calculate core mechanics, stress, strain, and deformation. The physical property module includes a core material physical property module, which is used to set the physical property parameters of the solid-state core. The physical property parameters of the solid-state core include, for example, thermal and structural physical property parameters of the solid-state core.

[0074] The coupled computation module can be divided into a data exchange module and an iterative convergence control module. The data exchange module handles data exchange between computational programs. The iterative convergence control module controls the convergence of computational programs and determines whether the computational programs terminate.

[0075] The neutron physics calculation module mainly includes the component calculation module and the core calculation module. The component calculation module is configured to: calculate the ultrafine group cross-section information of each material zone in the core from the point cross-section information; solve the neutron flux density distribution by solving the homogeneous problem moderation equation or the collision probability method; and merge the ultrafine group cross-sections into groups and regions.

[0076] The core calculation module is configured, for example, to: perform angle discrete calculations using a discrete ordinate method; and perform spatial discrete calculations using a node method of an arbitrary triangular grid.

[0077] For the thermal calculation module, the basic heat transfer process of the solid-state core is roughly as follows: fission reactions occur in the fuel rods to generate heat, which is transmitted by heat conduction within the fuel rods. This is a heat conduction problem with an internal heat source; the heat is then transferred from the fuel rods to the air gap and cladding. This is also a heat conduction process. The transfer of heat in the air gap may involve radiation heat exchange; the heat is conducted in the solid matrix. This process is also a heat conduction problem.

[0078] The main structures of a solid-state core include the fuel pellet, air gap, cladding, and substrate. The thermal calculation process is based on the three-dimensional heat conduction equation of the solid-state core and the boundary condition equations of the substrate's outer surface.

[0079] For the mechanical mechanics calculation module, since the solid-state core operates without a flowing working fluid and in a high-temperature environment, the mechanical effects caused by high temperatures are significant. The mechanical mechanics problem in the solid-state core is a high-temperature solid mechanics problem, primarily studying the forces, deformations, failures, and related changes and effects of the core's deformable solid structures under high temperatures. Based on the research content of the solid-state core mechanics, the key mechanical models that need to be established include physical models such as thermal stress and strain models and thermal expansion models.

[0080] This application scheme adopts the dual convergence criteria of the maximum temperature of the calculation domain and the effective proliferation coefficient of the core to ensure the accuracy of the coupled calculation. This application scheme performs calculations on the basis of the deterministic method. In the past, most multi-physics field coupling calculations were performed using the Monte Carlo method. The Monte Carlo method is mainly used for accurate modeling of the core, and a large number of iterative calculations are required to converge the results. In this method, the calculation is performed on the basis of the deterministic method, which not only ensures the accuracy of the calculation but also greatly reduces the amount of calculation and improves the calculation speed.

[0081] This application scheme comprehensively considers the nuclear physics, thermal engineering, and mechanical parameter performance of the solid-state core. Reactor physics, thermal engineering, and mechanical mechanics are complex, mutually coupled systems. The core operates at high temperatures, and the thermal expansion effect of the material is significant, which will produce large stress deformations. In addition, the temperature of the material varies at different locations, which will give the core a dynamic geometric boundary and also cause changes in the neutron distribution and mechanical properties of the material, thereby affecting the core's neutron physics processes. Therefore, this application scheme can improve the effectiveness and feasibility of the coupled calculation process.

[0082] This application scheme, by modeling and calculating the main multi-physics field coupling processes in the solid-state core, such as neutron transport, heat and mass transfer, and matrix expansion, can obtain the influence law and degree of the key parameters in each deterministic physical model on the physical process, and can analyze the coupling phenomena and coupling mechanisms between various physical fields, providing a solid foundation for the analysis and application of multi-physics field coupling in the solid-state core.

[0083] The present application also provides a nuclear reactor core operation analysis device. Figure 4 A schematic diagram of the components of a nuclear reactor core operation analysis device according to one embodiment of the present application is shown. The nuclear reactor core operation analysis device 400 may include an internal communication bus 401, a processor 402, a read-only memory (ROM) 403, a random access memory (RAM) 404, and a communication port 405. The nuclear reactor core operation analysis device 400 is connected to a network and other devices via the communication port. The internal communication bus 401 enables data communication between components of the nuclear reactor core operation analysis device 400. The processor 402 can make judgments and issue prompts. In some embodiments, the processor 402 may be composed of one or more processors. The communication port 405 enables the sending and receiving of information and data from the network. The nuclear reactor core operation analysis device 400 may also include various forms of program storage units and data storage units, such as a read-only memory (ROM) 403 and a random access memory (RAM) 404, which can store various data files used for computer processing and / or communication, as well as possible program instructions executed by the processor 402. The processor executes these instructions to implement the main part of the method. The results processed by the processor can be transmitted to the user device through the communication port and displayed on the user interface.

[0084] The above-mentioned nuclear reactor core operation analysis device 400 can be implemented as a computer program, stored in a memory, and recorded in the processor 402 for execution to implement the nuclear reactor core operation analysis method of the present application.

[0085] The present application also provides a computer-readable medium storing computer program code, which, when executed by a processor, implements the nuclear reactor core operation analysis method as described above.

[0086] Some aspects of the present application can be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software can be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". The processor can be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors or combinations thereof. In addition, various aspects of the present application may be expressed as computer products located in one or more computer-readable media, which include computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, tapes...), optical disks (e.g., compact disks CDs, digital versatile disks DVDs...), smart cards, and flash memory devices (e.g., cards, sticks, key drives...).

[0087] A computer-readable medium may include a propagated data signal embodying computer program code, for example, in baseband or as part of a carrier wave. The propagated signal may be in a variety of forms, including electromagnetic, optical, etc., or a suitable combination thereof. A computer-readable medium may be any computer-readable medium other than a computer-readable storage medium that can be connected to an instruction execution system, apparatus, or device to communicate, propagate, or transmit the program for use. The program code on the computer-readable medium may be transmitted via any suitable medium, including radio, cable, fiber optic cable, radio frequency signal, or similar medium, or any combination of the above.

[0088] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0089] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0090] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A method for analyzing nuclear reactor core operation, comprising: Establish a solid-state core geometry model; Meshing the geometric model and setting physical parameters and boundary conditions of the solid core; Establishing a neutron nuclear database, performing neutron physics calculations based on the neutron nuclear database and a meshed solid-state core geometric model to obtain power magnitude and power distribution results of the solid-state core, wherein the power magnitude and power distribution results of the solid-state core include power magnitude and power distribution results of fuel rod grid elements; Performing a thermal analysis calculation based on the power size and power distribution results of the solid-state core to obtain a temperature distribution result of the solid-state core, including: using the power size and power distribution results of the fuel rod grid cell as input data for the thermal analysis calculation, and performing a thermal analysis calculation based on the input data through a grid mapping operation and a data transfer operation; wherein the temperature distribution result of the solid-state core includes an average temperature of a fuel rod grid unit corresponding to the fuel rod grid cell and an average temperature of a nuclear reactor matrix grid cell; Based on the core temperature distribution results of the solid-state core, a mechanical analysis calculation is performed to obtain a deformation geometry calculation result, including: performing a mechanical analysis calculation on the average temperature of the fuel rod grid unit corresponding to the fuel rod grid element and the average temperature of the nuclear reactor matrix grid element through grid mapping and data transfer operations to obtain stress, strain and deformation calculation results of the fuel rod and the nuclear reactor matrix, as well as an average deformation calculation result of the fuel rod grid corresponding to the fuel rod grid element; Based on the core temperature distribution results of the solid-state core and the deformation geometry calculation results, the neutron physics calculation input data is updated, and the neutron physics calculation is iteratively performed until the results of the iterative calculation meet specific convergence conditions; Based on the results of the iterative calculation, the neutron physics parameters, temperature distribution parameters and stress-strain distribution parameters of the fixed core in a steady state are obtained.

2. The nuclear reactor core operation analysis method according to claim 1, characterized in that: Also includes: The parameter results corresponding to the steady-state situation are used as the initial values ​​for the transient calculation; Set the initial time, calculation time step and transient simulation time of transient calculation; When the total transient calculation running time is less than or equal to the set transient simulation time, the second stage neutron physics calculation is iterated until the total transient calculation running time is greater than the set transient simulation time; Based on the iterative results of the second-stage neutron physics calculations, the neutron physics parameters, temperature distribution parameters, and stress-strain distribution parameters of the fixed core under transient conditions are obtained.

3. The nuclear reactor core operation analysis method according to claim 1, characterized in that: The physical properties of the solid core include the initial temperature of the core material, the initial maximum temperature of the calculation domain and the initial effective proliferation coefficient of the core.

4. The nuclear reactor core operation analysis method according to claim 1, characterized in that: Based on the core temperature distribution results of the solid-state core and the deformation geometry calculation results, the neutron physics calculation input data is updated including: Based on the average temperature of the fuel rod grid unit corresponding to the fuel rod grid cell, the average temperature of the nuclear reactor matrix grid cell and the average deformation calculation results of the fuel rod grid corresponding to the fuel rod grid cell, the core material temperature and geometric parameters of the corresponding grid cell in the neutron physics calculation are updated.

5. The nuclear reactor core operation analysis method according to claim 1, characterized in that: The grid mapping operation includes performing grid mapping on the grid using a linear interpolation algorithm.

6. The nuclear reactor core operation analysis method according to claim 1, characterized in that: The data transfer operation includes: constructing a continuous interpolation function based on discrete data; integrating the continuous interpolation function within a unit volume of neutron physics calculation to obtain the unit internal average value of the required data; The units are obtained based on a grid division operation.

7. The nuclear reactor core operation analysis method according to claim 3, characterized in that: Based on the neutron physics calculation, the effective proliferation coefficient of the core is also obtained.

8. The nuclear reactor core operation analysis method according to claim 7, characterized in that: The specific convergence condition includes: the difference between the effective proliferation coefficient of the core and the initial effective proliferation coefficient of the core is less than a first parameter threshold, and the maximum temperature detection value of the calculation domain is less than a second parameter threshold.

9. The nuclear reactor core operation analysis method according to claim 1, characterized in that: The establishment of the neutron nuclear database comprises: Create a basic fine group cross-section database; Resonant self-screening calculations were performed based on the solid-state core geometry model to obtain the effective self-screening cross section suitable for neutron physics calculations. By combining the basic fine group cross section database with the effective self-screen cross section data, a fine group cross section database suitable for multi-physics coupling calculations of nuclear reactors is obtained. The narrow group cross section databases are merged to obtain a broad group cross section database suitable for neutron physics calculations.

10. A nuclear reactor core operation analysis system comprising: Core geometry modeling module, meshing module, initialization setting module, physical property module, calculation module and coupled calculation module; The calculation module includes neutron physics model calculation module, thermal model calculation module and mechanical mechanics model calculation module; the coupling calculation module can be divided into data exchange module and iterative convergence control module; The core geometry modeling module is used to establish a solid-state core geometry model; the meshing module is used to mesh the geometry model; the initialization setting module is used to set the boundary conditions of the solid-state core and establish a neutron nuclear database; the physical property module is used to set the physical property parameters of the solid-state core; The neutron physics model calculation module is used to implement the neutron physics calculation process to obtain the power size and power distribution results of the solid-state core, and the power size and power distribution results of the solid-state core include the power size and power distribution results of the fuel rod grid element; the thermal model calculation module is used to implement the thermal analysis calculation process, and the thermal analysis calculation process includes performing thermal analysis calculations based on the power size and power distribution results of the solid-state core to obtain the temperature distribution results of the solid-state core, including: using the power size and power distribution results of the fuel rod grid element as input data for the thermal analysis calculation, and performing thermal analysis calculations based on the input data through grid mapping operations and data transfer operations; wherein, the solid-state core The temperature distribution results include the average temperature of the fuel rod grid unit corresponding to the fuel rod grid element and the average temperature of the nuclear reactor matrix grid element; the mechanical mechanics model calculation module is used to implement the mechanical analysis calculation process, which includes performing mechanical analysis calculations based on the core temperature distribution results of the solid core to obtain deformation geometry calculation results, including: performing mechanical analysis calculations on the average temperature of the fuel rod grid unit corresponding to the fuel rod grid element and the average temperature of the nuclear reactor matrix grid element through grid mapping and data transfer operations to obtain stress, strain and deformation calculation results of the fuel rod and the nuclear reactor matrix, as well as the average deformation calculation results of the fuel rod grid corresponding to the fuel rod grid element; The data exchange module is used for data exchange operations of the model; the iterative convergence control module is used to perform convergence control operations on the iterative calculation process.

11. The nuclear reactor core operation analysis system according to claim 10, characterized in that: The physical property parameters include thermal physical property parameters and structural physical property parameters of the solid core.

12. The nuclear reactor core operation analysis system according to claim 10, characterized in that: The neutron physics model calculation module includes a component calculation module and a core calculation module; The component calculation module is configured to: calculate the ultrafine group cross-section information of each material zone in the core through point cross-section information; solve the neutron flux density distribution by solving the homogeneous problem moderation equation or the collision probability method; and merge the ultrafine group cross-sections into groups and zones; The core calculation module is configured to: perform angle discrete calculations using a discrete ordinate method; and perform spatial discrete calculations using a node method of an arbitrary triangular grid.

13. A nuclear reactor core operation analysis device, comprising: a memory for storing instructions executable by the processor; as well as A processor, configured to execute the instructions to implement the method according to any one of claims 1 to 9.

14. A computer-readable medium storing computer program code, wherein the computer program code implements the method according to any one of claims 1 to 9 when executed by a processor.

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