Method and apparatus for determining nuclear fuel effective thermal conductivity
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA NUCLEAR POWER TECH RES INST CO LTD
- Filing Date
- 2026-02-10
- Publication Date
- 2026-06-19
Smart Images
Figure CN122242104A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of nuclear fuel technology, and in particular to a method and apparatus for determining the equivalent thermal conductivity of nuclear fuel. Background Technology
[0002] With the continuous development of nuclear fuel and reactor safety analysis technology, dispersed nuclear fuel, due to its structural characteristics of easily fissile fuel particles being uniformly distributed in an inert matrix, has been widely used in research and testing reactors, high-temperature gas-cooled reactors, small modular reactors, and spent fuel processing.
[0003] In traditional techniques, numerical calculation methods for the equivalent thermal conductivity of dispersed nuclear fuel are mostly based on representative volume element models. These methods employ numerical techniques such as the finite element method to simulate the steady-state heat conduction process and calculate the overall thermal conductivity using homogenization theory. For example, existing research has achieved the prediction of the equivalent thermal conductivity of all-ceramic micro-encapsulated fuel pellets by establishing a two-phase model that includes fuel particles and an inert matrix. Other works have calculated the equivalent thermal conductivity along the thickness direction for specific dispersed fuel plates and explored the influence of particle distribution morphology on heat transfer.
[0004] However, the presence of fission bubbles significantly alters the microstructure and thermal properties of fuel particles. Ignoring their influence will cause the equivalent thermal conductivity assessment results to deviate from reality, thus affecting the accuracy of reactor thermal-hydraulic analysis and safety margin assessment. Therefore, there is an urgent need to develop a high-fidelity numerical calculation method that can comprehensively consider the three-phase effects of fission bubbles, fuel particle framework, and inert matrix to achieve accurate prediction of the equivalent thermal conductivity of nuclear fuel containing fission bubbles. Summary of the Invention
[0005] Therefore, it is necessary to provide a method and apparatus for determining the equivalent thermal conductivity of nuclear fuel that can accurately determine the equivalent thermal conductivity of nuclear fuel, in order to address the above-mentioned technical problems.
[0006] In a first aspect, this application provides a method for determining the equivalent thermal conductivity of nuclear fuel, including:
[0007] Obtain target simulated nuclear fuel; target simulated nuclear fuel is constructed based on target nuclear fuel; target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles and simulated inert matrix;
[0008] The first surface of the target simulated nuclear fuel is controlled to maintain a first temperature, and the second surface of the target simulated nuclear fuel is controlled to maintain a second temperature; the first surface and the second surface are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature;
[0009] Determine the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles;
[0010] The equivalent thermal conductivity of the target nuclear fuel is determined based on the particle heat flux density, matrix heat flux density, and bubble heat flux density.
[0011] In one embodiment, obtaining the target simulated nuclear fuel includes:
[0012] Obtain the fuel particle parameters of the simulated fuel particles in the initial simulated nuclear fuel;
[0013] For each fuel iteration process, simulated fission bubbles with non-overlapping positions are generated in the initial simulated nuclear fuel based on the fuel particle parameters.
[0014] Determine the proportion of all simulated fission bubbles in the initial simulated nuclear fuel under the current fuel iteration process;
[0015] If the proportion of bubbles is not greater than the preset proportion threshold, return to the step of generating non-overlapping simulated fission bubbles in the initial simulated nuclear fuel according to the fuel particle parameters, until the proportion of bubbles is greater than the preset proportion threshold, stop fuel iteration, and use the initial simulated nuclear fuel in the current iteration process as the target simulated nuclear fuel.
[0016] In one embodiment, based on fuel particle parameters, simulated fission bubbles with non-overlapping positions are generated in the initial simulated nuclear fuel, including:
[0017] For each bubble iteration process, based on the fuel particle parameters, the current simulated fission bubble under the current iteration process is generated at a random position in the initial simulated nuclear fuel;
[0018] For each historical simulated fission bubble, determine whether there is positional overlap between the current simulated fission bubble and the historical simulated fission bubble;
[0019] If the current simulated fission bubble overlaps with any historical simulated fission bubble, return to the step of generating the current simulated fission bubble in the current iteration process at a random location in the initial simulated nuclear fuel based on the fuel particle parameters, until the current simulated fission bubble no longer overlaps with the positions of all historical simulated fission bubbles, thus completing the simulated fission bubble generation operation in the current fuel iteration process.
[0020] In one embodiment, determining whether there is positional overlap between the current simulated fission bubble and historical simulated fission bubbles includes:
[0021] Determine the center-to-center distance between the current center of the simulated fission bubble and the historical center of the simulated fission bubble; and,
[0022] Determine the bubble sum value between the current bubble radius of the current simulated fission bubble and the historical bubble radius of the historical simulated fission bubble;
[0023] If the distance between the centers of the spheres is greater than the sum of the bubble values, it is determined that the positions of the current simulated fission bubble and the historical simulated fission bubble do not overlap.
[0024] If the distance between the centers of the spheres is not greater than the sum of the bubble values, determine the positional overlap between the current simulated fission bubble and the historical simulated fission bubble.
[0025] In one embodiment, the simulated fuel particles are constructed as follows:
[0026] Obtain the fuel particle distribution pattern, particle radius, and particle volume fraction in the target nuclear fuel;
[0027] The simulation side length of the initial simulated nuclear fuel is determined based on the particle radius and particle volume fraction.
[0028] Based on the distribution pattern of fuel particles and the simulation side length, simulated fuel particles in the initial simulated nuclear fuel are constructed.
[0029] In one embodiment, determining the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel includes:
[0030] Determine the heat flux density of simulated fission bubbles flowing from the first surface to the second surface in the target simulated nuclear fuel; and,
[0031] Determine the particle heat flux density of simulated fuel particles flowing from the first surface to the second surface in the target simulated nuclear fuel; and,
[0032] Determine the matrix heat flux density of the simulated inert matrix in the target simulated nuclear fuel as it flows from the first surface into the second surface.
[0033] In one embodiment, the target simulated nuclear fuel includes at least one detection point; determining the heat flux density of simulated fission bubbles flowing from a first surface to a second surface in the target simulated nuclear fuel includes:
[0034] For each detection point within different simulated fission bubbles in the target simulated nuclear fuel, determine the detection point temperature within the detection volume corresponding to that detection point;
[0035] The heat flux density of the bubble at the detection point is determined based on the temperature, volume, and gas description data at the detection point; the gas description data is the description data of the fission gas inside the simulated fission bubble to which the detection point belongs.
[0036] In one embodiment, the gas description data includes the mole fraction, molar mass, and thermal conductivity of the fission gas; determining the bubble heat flux density at the detection point based on the detection point temperature, detection volume, and gas description data includes:
[0037] The thermal conductivity of the simulated fission bubble is determined based on the mole fraction, molar mass, and thermal conductivity of the fission gas.
[0038] The heat flux density of the bubble at the detection point is determined based on the temperature, volume, and thermal conductivity of the bubble.
[0039] In one embodiment, the equivalent thermal conductivity of the target nuclear fuel is determined based on the particle heat flux density, the matrix heat flux density, and the bubble heat flux density, including:
[0040] The target heat flux density of the simulated nuclear fuel is determined based on the particle heat flux density, matrix heat flux density, bubble heat flux density, and detection volume.
[0041] The equivalent thermal conductivity of the target nuclear fuel is determined based on the target heat flux density.
[0042] Secondly, this application also provides a device for determining the equivalent thermal conductivity of nuclear fuel, comprising:
[0043] The acquisition module is used to acquire the target simulated nuclear fuel; the target simulated nuclear fuel is constructed based on the target nuclear fuel; the target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles and simulated inert matrix;
[0044] A control module is used to control a first surface of the target simulated nuclear fuel to maintain a first temperature, and to control a second surface of the target simulated nuclear fuel to maintain a second temperature; the first surface and the second surface are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature;
[0045] The density module is used to determine the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles;
[0046] The determination module is used to determine the equivalent thermal conductivity of the target nuclear fuel based on the particle heat flux density, matrix heat flux density, and bubble heat flux density.
[0047] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:
[0048] Obtain target simulated nuclear fuel; target simulated nuclear fuel is constructed based on target nuclear fuel; target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles and simulated inert matrix;
[0049] The first surface of the target simulated nuclear fuel is controlled to maintain a first temperature, and the second surface of the target simulated nuclear fuel is controlled to maintain a second temperature; the first surface and the second surface are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature;
[0050] Determine the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles;
[0051] The equivalent thermal conductivity of the target nuclear fuel is determined based on the particle heat flux density, matrix heat flux density, and bubble heat flux density.
[0052] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the following steps:
[0053] Obtain target simulated nuclear fuel; target simulated nuclear fuel is constructed based on target nuclear fuel; target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles and simulated inert matrix;
[0054] The first surface of the target simulated nuclear fuel is controlled to maintain a first temperature, and the second surface of the target simulated nuclear fuel is controlled to maintain a second temperature; the first surface and the second surface are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature;
[0055] Determine the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles;
[0056] The equivalent thermal conductivity of the target nuclear fuel is determined based on the particle heat flux density, matrix heat flux density, and bubble heat flux density.
[0057] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, performs the following steps:
[0058] Obtain target simulated nuclear fuel; target simulated nuclear fuel is constructed based on target nuclear fuel; target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles and simulated inert matrix;
[0059] The first surface of the target simulated nuclear fuel is controlled to maintain a first temperature, and the second surface of the target simulated nuclear fuel is controlled to maintain a second temperature; the first surface and the second surface are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature;
[0060] Determine the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles;
[0061] The equivalent thermal conductivity of the target nuclear fuel is determined based on the particle heat flux density, matrix heat flux density, and bubble heat flux density.
[0062] The aforementioned method and apparatus for determining the equivalent thermal conductivity of nuclear fuel achieves accurate numerical prediction of the equivalent thermal conductivity of real nuclear fuel by constructing a target simulated nuclear fuel containing simulated fission bubbles in a virtual environment and simulating its steady-state heat conduction process under a one-dimensional temperature difference. By incorporating fission bubbles as an independent heat conduction phase into the calculation model, the influence of bubbles on the overall thermal conductivity can be quantified, thus significantly improving the accuracy of assessing the thermal conduction performance of irradiated nuclear fuel. Compared to traditional methods, this method not only reflects the complex role of microstructure in heat transfer but also provides a more reliable theoretical basis for the thermal design and safety analysis of reactor fuel elements. Attached Figure Description
[0063] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0064] Figure 1 This embodiment provides an application environment diagram for a method for determining the equivalent thermal conductivity of nuclear fuel.
[0065] Figure 2A This is a flowchart illustrating the first method for determining the equivalent thermal conductivity of nuclear fuel provided in this embodiment.
[0066] Figure 2B This is a schematic diagram of a simulated nuclear fuel structure provided in this embodiment;
[0067] Figure 2C This embodiment provides a representative volume element cloud map;
[0068] Figure 3 This is a flowchart illustrating a target simulation nuclear fuel acquisition process provided in this embodiment;
[0069] Figure 4 This is a flowchart illustrating a simulated fission bubble generation process provided in this embodiment.
[0070] Figure 5 This is a flowchart illustrating the steps involved in constructing simulated fuel particles, as provided in this embodiment.
[0071] Figure 6 This is a flowchart illustrating a step for determining the heat flux density of a bubble, as provided in this embodiment.
[0072] Figure 7 This is a structural block diagram of a device for determining the equivalent thermal conductivity of nuclear fuel provided in this embodiment;
[0073] Figure 8 This is an internal structural diagram of a computer device provided in this embodiment. Detailed Implementation
[0074] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0075] Compared to traditional homogeneous fuels, dispersed nuclear fuels exhibit superior thermal conductivity, mechanical properties, radiation resistance, and accident tolerance. Furthermore, because fission reactions and radiation damage are primarily concentrated in the fuel particles and their adjacent matrix regions, they significantly reduce the risk of fuel element failure and enhance reactor safety. During the service life of dispersed nuclear fuels, the fuel particles generate fission gases through fission reactions. These gas atoms diffuse, aggregate, and form fission bubbles, gradually evolving the fuel particles into a porous structure, thus affecting the overall thermal conductivity of the nuclear fuel. Thermal conductivity, as a key parameter influencing the heat transfer efficiency and temperature distribution of nuclear fuel elements, directly relates to the reactor's economics and operational safety. Therefore, accurately assessing the equivalent thermal conductivity of dispersed nuclear fuels containing fission bubbles is of great significance for reactor safety design and performance optimization.
[0076] The method for determining the equivalent thermal conductivity of nuclear fuel provided in this application embodiment can be applied to, for example... Figure 1In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store data that server 104 needs to process. The data storage system can be integrated onto server 104 or placed on a cloud or other network server. A computer device acquires target simulated nuclear fuel; the target simulated nuclear fuel is constructed based on target nuclear fuel; the target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles, and a simulated inert matrix; the first surface of the target simulated nuclear fuel is controlled to maintain a first temperature, and the second surface of the target simulated nuclear fuel is controlled to maintain a second temperature; the first and second surfaces are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature; the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel is determined; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles; based on the particle heat flux density, the matrix heat flux density, and the bubble heat flux density, the equivalent thermal conductivity of the target nuclear fuel is determined. The terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. IoT devices can include smart speakers, smart TVs, smart air conditioners, and smart in-vehicle systems. Portable wearable devices can include smartwatches, smart bracelets, and head-mounted devices. The server 104 can be implemented using a standalone server or a server cluster consisting of multiple servers.
[0077] In one exemplary embodiment, such as Figure 2A As shown, a method for determining the equivalent thermal conductivity of nuclear fuel is provided, which can be applied to... Figure 1 Taking a computer device as an example, the explanation includes the following steps S201 to S204. Wherein:
[0078] S201 acquires target simulated nuclear fuel.
[0079] Among them, the target simulated nuclear fuel is a virtual model built based on the target nuclear fuel, used to simulate the physical behavior and thermal conductivity characteristics of real nuclear fuel in a computer environment; the target simulated nuclear fuel is constructed based on the target nuclear fuel. The target nuclear fuel refers to a composite material in which fissile fuel particles are uniformly distributed in an inert matrix.
[0080] For example, such as Figure 2BThe schematic diagram of the simulated nuclear fuel structure shown illustrates that the target simulated nuclear fuel includes: simulated fuel particles, a simulated inert matrix, and simulated fission bubbles. Simulated fission bubbles are a key component of the target simulated nuclear fuel, used to simulate the bubble structure generated by fission reactions in real nuclear fuel during irradiation. Simulated fuel particles are virtual models constructed in a computer simulation environment based on the physical properties of actual fuel particles in the target nuclear fuel. These particles simulate the distribution, size, and shape of fissile materials (such as oxides and carbides of uranium or plutonium) in real nuclear fuel and are a key component of the target simulated nuclear fuel model. The simulated inert matrix is the background material in the target simulated nuclear fuel model, excluding fuel particles and fission bubbles, simulating the inert material (such as graphite, SiC, and aluminum alloys) that encapsulates fuel particles in real nuclear fuel. Preferably, the simulated inert matrix in this embodiment can be an aluminum alloy matrix.
[0081] In some embodiments, the pre-constructed target simulated nuclear fuel can be directly obtained.
[0082] S202 controls the first surface of the target simulated nuclear fuel to maintain a first temperature, and controls the second surface of the target simulated nuclear fuel to maintain a second temperature.
[0083] In this simulation, the first and second surfaces are parallel to each other. The first surface refers to a specific surface in the target simulated nuclear fuel model along a predetermined direction (such as the positive x-axis). A higher temperature boundary condition is applied to this surface to simulate the actual heating of the nuclear fuel in the reactor. Specifically, in the numerical simulation, the first surface is usually set as the surface on the heat source side, i.e., the side where heat flows in. The second surface is another specific surface in the target simulated nuclear fuel model opposite to the first surface or along a predetermined direction (such as the negative x-axis). A lower temperature boundary condition is applied to this surface to simulate the heat dissipation of the nuclear fuel in the reactor. Specifically, the second surface is usually set as the side where heat flows out.
[0084] The first temperature is the temperature boundary condition value applied to the first surface. This temperature value is typically higher than the ambient temperature or the temperature of the second surface to simulate the high-temperature heating of nuclear fuel in the reactor. In the numerical simulation, the first temperature is a key input parameter that directly affects the heat conduction process and temperature distribution within the nuclear fuel. The second temperature is the temperature boundary condition value applied to the second surface. This temperature value is typically lower than the temperature of the first surface to simulate the heat dissipation process of nuclear fuel in the reactor. In the numerical simulation, the second temperature is also a key input parameter; together with the first temperature, it constitutes the temperature gradient within the nuclear fuel, thereby driving the heat conduction process. The first temperature is higher than the second temperature.
[0085] In some embodiments, a first temperature boundary of T0 (e.g., 373K) is set on the first surface of the target simulated nuclear fuel along a preset direction (e.g., the positive x-axis) to maintain the first temperature; a second temperature boundary of T0+1 (e.g., 374K) is set on the second surface of the target simulated nuclear fuel along the opposite direction (e.g., the negative x-axis) to maintain the second temperature.
[0086] S203 determines the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel.
[0087] Fuel heat flux density refers to the amount of heat passing through a unit area of simulated nuclear fuel per unit time, expressed in W / m². As a highly thermally conductive phase, the heat flux density of the inert matrix determines the efficiency of heat transfer from the high-temperature region to the low-temperature region. Fuel heat flux density includes the bubble heat flux density of the simulated fission bubbles, the particle heat flux density of the simulated fuel particles, and the matrix heat flux density of the simulated inert matrix.
[0088] The bubble heat flux density refers to the amount of heat passing through a simulated fission bubble per unit area in nuclear fuel per unit time, expressed in W / m². It reflects the influence of fission gases (such as xenon and krypton) within the fission bubble on overall heat conduction. Because fission bubbles contain fission gases with low thermal conductivity, they may hinder heat conduction or enhance heat transfer through gas convection; their net effect needs to be quantified through simulation.
[0089] Particle heat flux density specifically refers to the heat flux density of the simulated fuel particle skeleton (i.e., the fuel particle portion excluding fission bubbles), measured in W / m². It distinguishes the heat transfer contribution of the entire fuel particle from the internal fission bubbles, reflecting the intrinsic thermal conductivity of solid fuel materials.
[0090] The matrix heat flux density refers to the heat passing through a unit area of the simulated inert matrix in the nuclear fuel per unit time, expressed in W / m². It reflects the contribution of the inert matrix to overall heat conduction. As the material encapsulating fuel particles, the thermal conductivity of the inert matrix directly affects the macroscopic heat transfer efficiency of nuclear fuel elements. A low thermal conductivity matrix may become a thermal resistance, while a high thermal conductivity matrix enhances heat transfer.
[0091] In some embodiments, the heat flux density of simulated fission bubbles flowing from a first surface into a second surface in the target simulated nuclear fuel is determined; the heat flux density of simulated fuel particles flowing from the first surface into the second surface in the target simulated nuclear fuel is determined; and the heat flux density of simulated inert matrix flowing from the first surface into the second surface in the target simulated nuclear fuel is determined.
[0092] For example, based on a pre-written simulation program, all Gaussian integration points of the fission bubble, fuel particle skeleton and inert matrix are traversed to extract the volume and heat flux density in the x-direction of all Gaussian integration points.
[0093] For example, such as Figure 2C The representative volume element cloud diagram shown is shown in this embodiment. The square is a representative volume element containing fission bubble dispersion nuclear fuel. The macroscopic temperature gradient set in the x direction is 1K, and the temperature distribution cloud diagram of the representative volume element shown in (1) is obtained. The heat flux density distribution cloud diagram of the simulated inert matrix, the heat flux density distribution cloud diagram of the simulated fuel particle skeleton, and the heat flux density distribution cloud diagram of the simulated fission bubble are shown in (2).
[0094] S204 determines the equivalent thermal conductivity of the target nuclear fuel based on the particle heat flux density, matrix heat flux density, and bubble heat flux density.
[0095] Equivalent thermal conductivity refers to the overall equivalent thermal conductivity of a non-homogeneous medium (such as nuclear fuel containing fuel particles, fission bubbles, and an inert matrix) under steady-state thermal conduction conditions.
[0096] In some embodiments, based on a pre-written simulation program, the heat flux density in the x-direction of all Gaussian integral points of the fission bubble, fuel particle skeleton and inert matrix is volume averaged to calculate the equivalent thermal conductivity of the fission bubble-dispersed nuclear fuel under the current calculation temperature, fission bubble volume fraction and fuel particle volume fraction.
[0097] In some embodiments, the target heat flux density of the simulated nuclear fuel is determined based on the particle heat flux density, the matrix heat flux density, the bubble heat flux density, and the detection volume; and the equivalent thermal conductivity of the target nuclear fuel is determined based on the target heat flux density.
[0098] For example, the target heat flux density of the simulated nuclear fuel is determined based on the particle heat flux density, matrix heat flux density, bubble heat flux density and detection volume, as shown in the following formula (1).
[0099] (1)
[0100] in, This represents the target heat flux density of the simulated nuclear fuel; This represents the heat flux density in the x-direction at all Gaussian integration points in the simulated nuclear fuel, including fission bubbles, fuel particle skeleton, and inert matrix. Indicates the first The first unit The volume of a Gaussian integral point; This represents the number of Gaussian integration points within a single cell. This indicates the number of elements in the representative volume element finite element model containing fission bubble dispersed nuclear fuel.
[0101] For example, the equivalent thermal conductivity of the target nuclear fuel is determined based on the target heat flux density, as shown in the following formula (2).
[0102] (2)
[0103] in, This represents the target heat flux density of the simulated nuclear fuel. This represents the equivalent thermal conductivity of the simulated nuclear fuel.
[0104] The aforementioned method and apparatus for determining the equivalent thermal conductivity of nuclear fuel achieves accurate numerical prediction of the equivalent thermal conductivity of real nuclear fuel by constructing a target simulated nuclear fuel containing simulated fission bubbles in a virtual environment and simulating its steady-state heat conduction process under a one-dimensional temperature difference. By incorporating fission bubbles as an independent heat conduction phase into the calculation model, the influence of bubbles on the overall thermal conductivity can be quantified, thus significantly improving the accuracy of assessing the thermal conduction performance of irradiated nuclear fuel. Compared to traditional methods, this method not only reflects the complex role of microstructure in heat transfer but also provides a more reliable theoretical basis for the thermal design and safety analysis of reactor fuel elements.
[0105] Figure 3 This is a flowchart illustrating the steps for obtaining the target simulated nuclear fuel in one embodiment. This embodiment refines the steps for obtaining the target simulated nuclear fuel in the above embodiments, including the following steps:
[0106] S301 obtains the fuel particle parameters of the simulated fuel particles in the initial simulated nuclear fuel.
[0107] Among them, fuel particle parameters describe the microscopic particles (such as fuel particles) in nuclear fuel. The key physical properties of nuclear fuel (particles, TRISO particles, or U3Si2 particles) directly affect the thermal conductivity, mechanical properties, irradiation behavior, and safety of nuclear fuel.
[0108] In some embodiments, the fuel particle parameters of the simulated fuel particles in the initial simulated nuclear fuel are directly obtained.
[0109] For each fuel iteration, S302 generates simulated fission bubbles with non-overlapping positions in the initial simulated nuclear fuel based on the fuel particle parameters.
[0110] The initial simulated nuclear fuel is the benchmark material used for modeling and analysis in nuclear fuel virtual simulation technology. It should be noted that the initial simulated nuclear fuel includes simulated fuel particles and simulated inert matrix.
[0111] In some embodiments, the radius and center coordinates of fission bubbles are randomly generated based on the center coordinates and radius of the simulated fuel particles, and the fission bubbles are controlled to be located inside the fuel particles, with no overlap between the fission bubbles, and the sum of the volumes of the fission bubbles in each fuel particle reaches the target fission bubble volume fraction; simulated fission bubbles with non-overlapping positions are generated based on the radius and center coordinates of the fission bubbles.
[0112] For example, in this embodiment, the radius of the fission bubble is set to be in the range of 0.0006~0.0015 mm, and the formula for the random radius function is: ;in, This represents the radius of the j-th fission bubble located inside the i-th fuel particle.
[0113] For example, in this embodiment, the coordinates of the center of the fission bubble are randomly generated based on the following function (3), which is used to generate a random floating-point number within a specified range.
[0114] (3)
[0115] in, This represents the x-coordinate of the j-th fission bubble inside the i-th simulated fuel particle in the Cartesian coordinate system. This represents the y-coordinate of the j-th fission bubble inside the i-th simulated fuel particle in the Cartesian coordinate system. This represents the z-axis coordinate of the j-th fission bubble inside the i-th simulated fuel particle in the Cartesian coordinate system. This represents the x-coordinate of the i-th simulated fuel particle in the Cartesian coordinate system; This represents the y-coordinate of the i-th simulated fuel particle in the Cartesian coordinate system; This represents the z-direction coordinate of the i-th simulated fuel particle in the Cartesian coordinate system; Indicates the radius of the fuel particle; This represents the radius of the j-th fission bubble located inside the i-th fuel particle.
[0116] For example, this embodiment controls the location of fission bubbles inside fuel particles based on the following formula (4):
[0117] (4)
[0118] in, This represents the x-coordinate of the j-th fission bubble inside the i-th simulated fuel particle in the Cartesian coordinate system. This represents the y-coordinate of the j-th fission bubble inside the i-th simulated fuel particle in the Cartesian coordinate system; z i,jThis represents the z-axis coordinate of the j-th fission bubble inside the i-th simulated fuel particle in the Cartesian coordinate system; x i The x-coordinate represents the coordinate of the i-th simulated fuel particle in the Cartesian coordinate system; the y-coordinate represents the coordinate of the i-th simulated fuel particle in the x-direction. i The z-coordinate represents the y-direction coordinate of the i-th simulated fuel particle in the Cartesian coordinate system; i R represents the z-axis coordinate of the i-th simulated fuel particle in the Cartesian coordinate system; p R represents the radius of the fuel particle; b,i,j This represents the radius of the j-th fission bubble located inside the i-th fuel particle.
[0119] S303 determines the proportion of all simulated fission bubbles in the initial simulated nuclear fuel during the current fuel iteration process.
[0120] In some embodiments, the proportion of all simulated fission bubbles in the initial simulated nuclear fuel under the current fuel iteration process is determined based on the following formula (5).
[0121] (5)
[0122] in, Let n be the volume of the nth fission bubble inside the i-th fuel particle; Let be the volume of the i-th fuel particle.
[0123] If the bubble proportion is not greater than the preset proportion threshold, S304 returns to the step of generating non-overlapping simulated fission bubbles in the initial simulated nuclear fuel according to the fuel particle parameters, until the bubble proportion is greater than the preset proportion threshold, then stops the fuel iteration, and uses the initial simulated nuclear fuel in the current iteration process as the target simulated nuclear fuel.
[0124] For example, the preset percentage threshold in this embodiment can be 0.05.
[0125] In some embodiments, if the proportion of bubbles is not greater than a preset proportion threshold, the generation of the fission bubble radius and sphere center coordinate data inside the i-th fuel particle is completed; if the proportion of bubbles is greater than the preset proportion threshold, the fuel particles and fission bubble portions outside the cube region are cut off and removed, and Boolean operations are used on the simulated inert matrix, simulated fuel particles, and simulated fission bubbles to generate the target simulated nuclear fuel containing fission bubble dispersion type nuclear fuel.
[0126] In the above embodiments, by iteratively generating simulated fission bubbles and determining in real time whether the bubble proportion meets the threshold requirement, a fission bubble distribution that conforms to the actual irradiation evolution law can be dynamically and controllably constructed in simulated nuclear fuel. This method not only ensures that the bubbles do not overlap in space and conform to physical reality, but also precisely controls the total integral number of bubbles in the fuel, thereby effectively simulating the microstructural changes of nuclear fuel under different irradiation levels. This provides a highly realistic and parameter-adjustable simulation model for subsequent heat conduction analysis, significantly improving the representativeness and reliability of the equivalent thermal conductivity numerical calculation.
[0127] Figure 4 This is a flowchart illustrating the simulated fission bubble generation steps in one embodiment. This embodiment refines the steps in the above embodiment for generating non-overlapping simulated fission bubbles in the initial simulated nuclear fuel based on fuel particle parameters, including the following steps:
[0128] For each bubble iteration, S401 generates the current simulated fission bubble at a random location in the initial simulated nuclear fuel, based on the fuel particle parameters.
[0129] In some embodiments, the radius and center coordinates of fission bubbles are randomly generated based on the center coordinates and radius of the simulated fuel particles, so as to generate the current simulated fission bubble in the current iteration process at a random position in the initial simulated nuclear fuel.
[0130] S402 determines whether the current simulated fission bubble and the historical simulated fission bubble overlap in position for each historical simulated fission bubble.
[0131] In some embodiments, the center-to-center distance between the current center of the current simulated fission bubble and the historical center of the historical simulated fission bubble is determined; and the bubble sum value between the current bubble radius of the current simulated fission bubble and the historical bubble radius of the historical simulated fission bubble is determined; if the center-to-center distance is greater than the bubble sum value, it is determined that the positions of the current simulated fission bubble and the historical simulated fission bubble do not overlap; if the center-to-center distance is not greater than the bubble sum value, it is determined that the positions of the current simulated fission bubble and the historical simulated fission bubble overlap.
[0132] For example, starting from the j-th (j>1) fission bubble, it is determined whether there is geometric overlap with all previous fission bubbles located in the same fuel particle. If there is overlap, the radius and center coordinates of the fission bubble are regenerated. The method for determining whether there is geometric overlap is as follows: a loop algorithm is established to calculate the center distance between the j-th fission bubble and each fission bubble previously constructed in the same fuel particle. If the center distance is greater than the sum of the radii of the two fission bubbles, it is determined that there is no geometric overlap; otherwise, the radius and center coordinates of the fission bubble are regenerated. The function for determining whether there is geometric overlap of fission bubbles is as shown in the following formula (6):
[0133] (6)
[0134] Where, x i,n The x-coordinate of the nth fission bubble inside the i-th fuel particle in the Cartesian coordinate system; y i,n The z-coordinate represents the y-axis coordinate of the nth fission bubble inside the i-th fuel particle in the Cartesian coordinate system; i,n R represents the z-axis coordinate of the nth fission bubble inside the i-th fuel particle in the Cartesian coordinate system; b,i,n This represents the radius of the nth fission bubble located inside the i-th fuel particle.
[0135] If the current simulated fission bubble overlaps with any historical simulated fission bubble, S403 returns to the step of generating the current simulated fission bubble in the current iteration process at a random location in the initial simulated nuclear fuel according to the fuel particle parameters, until the current simulated fission bubble does not overlap with the positions of all historical simulated fission bubbles, thus completing the simulated fission bubble generation operation in the current fuel iteration process.
[0136] In the above embodiments, a bubble-by-bubble iteration and position overlap detection mechanism ensures that each simulated fission bubble generated in the initial simulated nuclear fuel is located in a random and non-overlapping spatial position. This process effectively simulates the physical laws of fission gas nucleation and growth in a real irradiation environment, avoiding non-physical overlap of the bubble model, thereby constructing a diffuse bubble distribution that more closely resembles the actual microstructure. This method significantly improves the geometric realism and physical rationality of the simulation model, providing a reliable microstructure basis that conforms to the laws of material evolution for subsequent numerical simulations of heat conduction.
[0137] Figure 5 This is a flowchart illustrating the simulated fuel particle construction steps in one embodiment. This embodiment refines the steps for constructing simulated fuel particles described in the previous embodiment, including the following steps:
[0138] S501 obtains the fuel particle distribution pattern, particle radius, and particle volume fraction of the target nuclear fuel.
[0139] The fuel particle distribution pattern refers to the spatial arrangement of fuel particles within the matrix material, which determines the contact mode between particles, heat flow path, and stress distribution. Particle radius is a typical size parameter of fuel particles, usually referring to the radius of spherical particles or the equivalent radius of non-spherical particles. Particle volume fraction is the proportion of fuel particle volume to the total fuel volume.
[0140] S502 determines the simulation side length of the initial simulated nuclear fuel based on the particle radius and particle volume fraction.
[0141] In some embodiments, the simulated side length of the initial simulated nuclear fuel is determined based on the following formula (7), according to the particle radius and particle volume fraction.
[0142] (7)
[0143] Among them, R p Indicates the radius of the fuel particle. R represents the fuel particle volume fraction, and L represents the simulation side length. p It can be 0.030mm; It can be 0.25; L can be 0.09672mm.
[0144] S503 constructs simulated fuel particles in the initial simulated nuclear fuel based on the fuel particle distribution pattern and simulation side length.
[0145] In some embodiments, the coordinates of the center of the sphere of all fuel particles are calculated based on the distribution pattern of the fuel particles and the simulated side length to construct the simulated fuel particles in the initial simulated nuclear fuel.
[0146] In the above embodiments, by acquiring key geometric parameters such as the actual particle distribution, size, and volume fraction of the target nuclear fuel, and adaptively determining the boundary dimensions of the simulation model accordingly, a simulated fuel particle structure that highly replicates the real fuel in both geometry and spatial arrangement is constructed. This method ensures the geometric consistency between the virtual simulation model and the physical entity at the microscale, laying a realistic geometric foundation for subsequent accurate simulation of fission bubble distribution and heat conduction behavior, and significantly improving the credibility and engineering applicability of the overall equivalent thermal conductivity calculation model.
[0147] Figure 6 This is a flowchart illustrating the steps for determining bubble heat flux density in one embodiment. In this embodiment, the target simulated nuclear fuel includes at least one detection point. This embodiment refines the steps for determining the bubble heat flux density of simulated fission bubbles flowing from the first surface to the second surface in the target simulated nuclear fuel, as described in the previous embodiment, and includes the following steps:
[0148] S601 determines the temperature at each detection point within the detection volume corresponding to the detection point for each detection point in the target simulated nuclear fuel.
[0149] S602 determines the bubble heat flux density at the detection point based on the detection point temperature, detection volume, and gas description data.
[0150] The gas description data refers to the descriptive data of the fission gas within the simulated fission bubble at the detection point. This data includes the mole fraction, molar mass, and thermal conductivity of the fission gas.
[0151] In some embodiments, the bubble thermal conductivity of the simulated fission bubble is determined based on the mole fraction, molar mass, and thermal conductivity of the fission gas; and the bubble heat flux density at the detection point is determined based on the temperature at the detection point, the detection volume, and the bubble thermal conductivity.
[0152] For example, based on the following formula (8), the bubble thermal conductivity of the simulated fission bubble is determined according to the mole fraction, molar mass and thermal conductivity of the fission gas.
[0153] (8)
[0154] Where, k mix k represents the thermal conductivity of fission bubbles. l The thermal conductivity of the fission gas component l is represented by k, where l = 1, 2; m The thermal conductivity of fission gas component m is represented by l = 1, 2; x l x represents the mole fraction of fission gas component l; m M represents the mole fraction of fission gas component m; l M represents the molar mass of fission gas component l; m This represents the molar mass of the fission gas component m.
[0155] It should be noted that in this embodiment, the fission gas composition inside the fission bubble is considered to be xenon and krypton, and the thermal conductivity of xenon fission gas is: The thermal conductivity of krypton fission gas is: .
[0156] It should be noted that the thermal conductivity of the simulated fuel particles in this embodiment is: The thermal conductivity of the simulated inert matrix is: .
[0157] In the above embodiments, by setting detection points inside the simulated fission bubble and calculating the bubble heat flux density point by point based on the temperature field within the local detection volume and the specific physical properties of the fission gas (such as gas description data), a refined description of the non-uniform heat conduction behavior inside the bubble is achieved. This method can accurately reflect the influence of gas composition and temperature gradient at different locations on heat flux, thereby more realistically simulating the actual heat transfer contribution of fission bubbles in nuclear fuel, and significantly improving the physical accuracy and numerical reliability of the bubble phase heat transport model in the calculation of equivalent thermal conductivity.
[0158] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.
[0159] Based on the same inventive concept, this application also provides a nuclear fuel equivalent thermal conductivity determination apparatus for implementing the aforementioned method for determining nuclear fuel equivalent thermal conductivity. The solution provided by this apparatus is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the nuclear fuel equivalent thermal conductivity determination apparatus provided below can be found in the limitations of the nuclear fuel equivalent thermal conductivity determination method described above, and will not be repeated here.
[0160] In one exemplary embodiment, such as Figure 7 As shown, a device for determining the equivalent thermal conductivity of nuclear fuel is provided, comprising: an acquisition module 701, a control module 702, a density module 703, and a determination module 704, wherein:
[0161] The acquisition module 701 is used to acquire the target simulated nuclear fuel; the target simulated nuclear fuel is constructed based on the target nuclear fuel; the target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles and simulated inert matrix;
[0162] The control module 702 is used to control the first surface of the target simulated nuclear fuel to maintain a first temperature, and to control the second surface of the target simulated nuclear fuel to maintain a second temperature; the first surface and the second surface are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature;
[0163] Density module 703 is used to determine the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles;
[0164] The determination module 704 is used to determine the equivalent thermal conductivity of the target nuclear fuel based on the particle heat flux density, the matrix heat flux density, and the bubble heat flux density.
[0165] In some embodiments, the acquisition module 701 is further configured to acquire fuel particle parameters of simulated fuel particles in the initial simulated nuclear fuel; for each fuel iteration process, generate simulated fission bubbles with non-overlapping positions in the initial simulated nuclear fuel according to the fuel particle parameters; the initial simulated nuclear fuel includes simulated fuel particles and a simulated inert matrix; determine the bubble proportion of all simulated fission bubbles in the initial simulated nuclear fuel under the current fuel iteration process; if the bubble proportion is not greater than a preset proportion threshold, return to the step of generating simulated fission bubbles with non-overlapping positions in the initial simulated nuclear fuel according to the fuel particle parameters, until the bubble proportion is greater than the preset proportion threshold, stop the fuel iteration, and take the initial simulated nuclear fuel under the current iteration process as the target simulated nuclear fuel.
[0166] In some embodiments, the acquisition module 701 is further configured to, for each bubble iteration process, generate the current simulated fission bubble at a random position in the initial simulated nuclear fuel according to the fuel particle parameters; for each historical simulated fission bubble, determine whether the current simulated fission bubble and the historical simulated fission bubble overlap in position; if the current simulated fission bubble overlaps with any historical simulated fission bubble, return to the step of generating the current simulated fission bubble at a random position in the initial simulated nuclear fuel according to the fuel particle parameters, until the current simulated fission bubble does not overlap with the positions of all historical simulated fission bubbles, thus completing the simulation fission bubble generation operation in the current fuel iteration process.
[0167] In some embodiments, the acquisition module 701 is further configured to determine the center-to-center distance between the current center of the current simulated fission bubble and the historical center of the historical simulated fission bubble; and to determine the bubble sum value between the current bubble radius of the current simulated fission bubble and the historical bubble radius of the historical simulated fission bubble; if the center-to-center distance is greater than the bubble sum value, determine that the positions of the current simulated fission bubble and the historical simulated fission bubble do not overlap; if the center-to-center distance is not greater than the bubble sum value, determine that the positions of the current simulated fission bubble and the historical simulated fission bubble overlap.
[0168] In some embodiments, the acquisition module 701 is further configured to acquire the fuel particle distribution pattern, particle radius, and particle volume fraction of the fuel particles in the target nuclear fuel; determine the simulation side length of the initial simulated nuclear fuel based on the particle radius and particle volume fraction; and construct the simulated fuel particles in the initial simulated nuclear fuel based on the fuel particle distribution pattern and simulation side length.
[0169] In some embodiments, the density module 703 is further configured to determine the bubble heat flux density of simulated fission bubbles flowing from the first surface into the second surface in the target simulated nuclear fuel; and to determine the particle heat flux density of simulated fuel particles flowing from the first surface into the second surface in the target simulated nuclear fuel; and to determine the matrix heat flux density of simulated inert matrix flowing from the first surface into the second surface in the target simulated nuclear fuel.
[0170] In some embodiments, the density module 703 is further configured to determine the temperature of the detection point within the detection volume of each detection point in different simulated fission bubbles in the target simulated nuclear fuel; determine the bubble heat flux density of the detection point based on the detection point temperature, detection volume, and gas description data; the gas description data is the description data of the fission gas within the simulated fission bubble to which the detection point belongs.
[0171] In some embodiments, the density module 703 is further configured to determine the bubble thermal conductivity of the simulated fission bubble based on the mole fraction, molar mass and thermal conductivity of the fission gas; and to determine the bubble heat flux density at the detection point based on the detection point temperature, detection volume and bubble thermal conductivity.
[0172] In some embodiments, the determining module 704 is further configured to determine the target heat flux density of the simulated nuclear fuel based on the particle heat flux density, the matrix heat flux density, the bubble heat flux density, and the detection volume; and to determine the equivalent thermal conductivity of the target nuclear fuel based on the target heat flux density.
[0173] Each module in the aforementioned nuclear fuel equivalent thermal conductivity determination device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, so that the processor can call and execute the operations corresponding to each module.
[0174] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 8As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores data. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network. When executed by the processor, the computer program implements a method for determining the equivalent thermal conductivity of nuclear fuel.
[0175] Those skilled in the art will understand that Figure 8 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0176] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.
[0177] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.
[0178] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.
[0179] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.
[0180] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.
[0181] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0182] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A method for determining the equivalent thermal conductivity of nuclear fuel, characterized in that, The method includes: Obtain target simulated nuclear fuel; the target simulated nuclear fuel is constructed based on target nuclear fuel; the target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles and simulated inert matrix; The first surface of the target simulated nuclear fuel is controlled to maintain a first temperature, and the second surface of the target simulated nuclear fuel is controlled to maintain a second temperature; the first surface and the second surface are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature; Determine the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles; The equivalent thermal conductivity of the target nuclear fuel is determined based on the particle heat flux density, the matrix heat flux density, and the bubble heat flux density.
2. The method according to claim 1, characterized in that, The acquisition of the target simulated nuclear fuel includes: Obtain the fuel particle parameters of the simulated fuel particles in the initial simulated nuclear fuel; For each fuel iteration process, based on the fuel particle parameters, simulated fission bubbles with non-overlapping positions are generated in the initial simulated nuclear fuel. Determine the proportion of all simulated fission bubbles in the initial simulated nuclear fuel under the current fuel iteration process; If the proportion of bubbles is not greater than a preset proportion threshold, return to the step of generating non-overlapping simulated fission bubbles in the initial simulated nuclear fuel according to the fuel particle parameters, until the proportion of bubbles is greater than the preset proportion threshold, stop fuel iteration, and use the initial simulated nuclear fuel in the current iteration process as the target simulated nuclear fuel.
3. The method according to claim 2, characterized in that, The step of generating non-overlapping simulated fission bubbles in the initial simulated nuclear fuel according to the fuel particle parameters includes: For each bubble iteration process, based on the fuel particle parameters, the current simulated fission bubble under the current iteration process is generated at a random position in the initial simulated nuclear fuel. For each historical simulated fission bubble, determine whether the current simulated fission bubble and the historical simulated fission bubble overlap in position; If the current simulated fission bubble overlaps with any historical simulated fission bubble, return to the step of generating the current simulated fission bubble in the current iteration process at a random location in the initial simulated nuclear fuel according to the fuel particle parameters, until the current simulated fission bubble does not overlap with the positions of all historical simulated fission bubbles, thus completing the simulated fission bubble generation operation in the current fuel iteration process.
4. The method according to claim 3, characterized in that, Determining whether the current simulated fission bubble and the historical simulated fission bubble overlap in position includes: Determine the center-to-center distance between the current center of the simulated fission bubble and the historical center of the simulated fission bubble; and, Determine the bubble sum value between the current bubble radius of the current simulated fission bubble and the historical bubble radius of the historical simulated fission bubble; If the distance between the centers of the spheres is greater than the sum of the values of the bubbles, it is determined that the positions of the current simulated fission bubble and the historical simulated fission bubble do not overlap. If the distance between the centers of the spheres is not greater than the sum of the bubble values, it is determined that the positions of the current simulated fission bubble and the historical simulated fission bubble overlap.
5. The method according to claim 2, characterized in that, The simulated fuel particles were constructed in the following manner: Obtain the fuel particle distribution pattern, particle radius, and particle volume fraction of the fuel particles in the target nuclear fuel; The simulated side length of the initial simulated nuclear fuel is determined based on the particle radius and the particle volume fraction. Based on the fuel particle distribution pattern and the simulation side length, simulated fuel particles in the initial simulated nuclear fuel are constructed.
6. The method according to claim 1, characterized in that, The determination of the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel includes: Determine the heat flux density of simulated fission bubbles flowing from the first surface to the second surface in the target simulated nuclear fuel; and, Determine the particle heat flux density of simulated fuel particles flowing from the first surface to the second surface in the target simulated nuclear fuel; and, Determine the matrix heat flux density of the simulated inert matrix in the target simulated nuclear fuel as it flows from the first surface into the second surface.
7. The method according to claim 6, characterized in that, The target simulated nuclear fuel includes at least one detection point; determining the heat flux density of simulated fission bubbles flowing from the first surface to the second surface in the target simulated nuclear fuel includes: For each detection point within different simulated fission bubbles in the target simulated nuclear fuel, determine the detection point temperature within the detection volume corresponding to that detection point. The heat flux density of the bubble at the detection point is determined based on the temperature at the detection point, the detection volume, and the gas description data; the gas description data is the description data of the fission gas inside the simulated fission bubble to which the detection point belongs.
8. The method according to claim 7, characterized in that, The gas description data includes the mole fraction, molar mass, and thermal conductivity of the fission gas; determining the bubble heat flux density at the detection point based on the temperature at the detection point, the detection volume, and the gas description data includes: The thermal conductivity of the simulated fission bubble is determined based on the mole fraction, molar mass, and thermal conductivity of the fission gas. The heat flux density of the bubble at the detection point is determined based on the temperature at the detection point, the detection volume, and the bubble thermal conductivity.
9. The method according to claim 1, characterized in that, Determining the equivalent thermal conductivity of the target nuclear fuel based on the particle heat flux density, the matrix heat flux density, and the bubble heat flux density includes: The target heat flux density of the simulated nuclear fuel is determined based on the particle heat flux density, the matrix heat flux density, the bubble heat flux density, and the detection volume. The equivalent thermal conductivity of the target nuclear fuel is determined based on the target heat flux density.
10. A device for determining the equivalent thermal conductivity of nuclear fuel, characterized in that, The device includes: An acquisition module is used to acquire target simulated nuclear fuel; the target simulated nuclear fuel is constructed based on target nuclear fuel; the target simulated nuclear fuel includes simulated fission bubbles, simulated fuel particles, and simulated inert matrix; A control module is configured to control a first surface of the target simulated nuclear fuel to maintain a first temperature, and to control a second surface of the target simulated nuclear fuel to maintain a second temperature; the first surface and the second surface are parallel in the target simulated nuclear fuel; the first temperature is higher than the second temperature; The density module is used to determine the fuel heat flux density flowing from the first surface to the second surface in the target simulated nuclear fuel; the fuel heat flux density includes the particle heat flux density of the simulated fuel particles, the matrix heat flux density of the simulated inert matrix, and the bubble heat flux density of the simulated fission bubbles; The determination module is used to determine the equivalent thermal conductivity of the target nuclear fuel based on the particle heat flux density, the matrix heat flux density, and the bubble heat flux density.