Simulation method and system for pebble bed dust migration filtering characteristics, terminal and medium

Abstract

The invention discloses a pebble bed dust migration filtering characteristic simulation method and system, a terminal and a medium, and relates to the field of fusion reactor nuclear fuel circulation. The simulation method comprises the steps of cladding multiplication pebble bed particle accumulation simulation, pebble bed structure data transmission, tritium extraction gas purging simulation in a cladding multiplication pebble bed, flow field data transmission, radioactive dust particle movement migration process simulation in the cladding multiplication pebble bed and radioactive dust particle capture deposition process simulation in the cladding multiplication pebble bed. And finally, obtaining data through result post-processing, and carrying out analog simulation analysis on the blowing migration filtering characteristics of the radioactive dust in the pebble bed of the fusion reactor cladding multiplication tritium production area under different multiplication cladding types, different blowing working conditions and different dust characteristics. According to the method, detailed dust migration filtering characteristic data can be obtained, and the purpose of improving the fineness and accuracy of radioactive dust migration filtering behavior simulation is achieved.

Description

Technical Field

[0001] This invention relates to the field of nuclear fuel cycle in fusion reactors, specifically to a method, system, terminal, and medium for simulating the migration and filtration characteristics of dust on a pebble bed. Background Technology

[0002] The spheres in the fusion reactor blanket are granular materials. When the particles move, the entire sphere exhibits fluid-like properties. For example, particle flow within the blanket can fill cavities of any complex shape. Mechanical vibration can promote particle movement and rearrangement, increasing the packing factor. The discrete nature of the particles effectively mitigates the thermal expansion and swelling effects of the spheres in the fusion reactor blanket. Therefore, spherical particles are mostly chosen as functional materials in the solid blanket. However, when the granular material is bounded by boundaries, it also possesses the properties of a solid material, capable of bearing certain loads. For instance, when the mechanical structure deforms and compresses the spheres inside the blanket, the movement of the particles can alleviate some of the stress, while still maintaining sufficient strength to withstand the deformation loads of the structural walls. When the compressive load on the spheres is too large, due to the concentrated contact stress near the contact points between particles, some particles in the spheres may break or pulverize.

[0003] During service, the fusion reactor blanket pebble bed must withstand harsh operating environments, including high-energy neutron radiation, high temperatures, thermal expansion, large temperature gradients, and structural wall compression. Inevitably, some particles will break down or pulverize, generating radioactive dust that poses a threat to the integrity of the solid blanket pebble bed structure and the safety of the blanket. If this dust is blown out of the bed and enters the subsequent tritium extraction system (TES), it may affect the tritium extraction efficiency. Furthermore, from a tritium production perspective, large fragments from broken microspheres are not blown out of the bed; they remain within the bed and perform their functions. Only very small dust particles are blown out. If this radioactive dust accumulates in the pipes, it poses a safety risk to the maintenance of the fusion reactor. Therefore, a simulation analysis of the purging and migration behavior of tiny dust particles within a randomly packed solid blanket pebble bed was conducted. This yielded the gas flow field and the distribution characteristics of tiny dust particles within the blanket pebble bed, and the dust filtration efficiency was evaluated. This is significant for the optimization analysis of the blanket and tritium extraction system. However, due to the complex structure of the fusion reactor blanket pebble bed and the extremely small size of the dust particles, the purging and migration process cannot be evaluated experimentally. Furthermore, simulation and evaluation methods for the purging, migration, and filtration characteristics of radioactive dust in the fusion reactor blanket are lacking. Summary of the Invention

[0004] The purpose of this invention is to provide a method, system, terminal, and medium for simulating the migration and filtration characteristics of dust in a fusion reactor blanket. This aims to address the problems in the existing technology where the structure of the fusion reactor blanket sphere bed is complex, the dust particles are too small to be evaluated from an experimental perspective, and there is a lack of simulation and evaluation methods for the migration and filtration characteristics of radioactive dust in the fusion reactor blanket.

[0005] Firstly, this invention provides a method for simulating the dust migration and filtration characteristics of a ball bed, including the following steps: Set the geometric parameters of the ball bed, the particle material properties, the particle size parameters, and the particle size distribution parameters. Gradually add particles to the ball bed in the calculation area inside the ball bed using the gravity rain method. The particles fall and accumulate in the container at the bottom of the ball bed. Stop adding particles when the target height or target number of particles is obtained. The particle accumulation enters the energy dissipation and stable equilibrium stage, and the ball bed model data with the target parameters is obtained. A ball bed model is established based on the obtained ball bed model data. The ball bed model is processed, and then the fluid domain and particle surface in the pores of the ball bed are meshed. Fluid calculation boundary conditions are set, and numerical solutions are performed to obtain the pore flow field data of the ball bed. Based on the ball bed model, particle and ball bed wall models are established. The particles in the discrete phase model are used to represent discrete dust particles inside the ball bed. The dust particle generation method and initial condition parameters are set. The drag force on the dust particles is calculated by the flow field data obtained by computational fluid dynamics. Then, the drag force and gravity results are added to the force situation of the dust particles, and the motion equation of the dust particles is solved. The adsorption state between dust particles and particle walls is analyzed by updating the dust particle information after the motion state is updated. The adsorption state of the particles is determined according to the set dust particle adsorption and capture probability. The dust particle information is updated and the force situation of the particles is solved again. The process is iterated continuously. The end time is determined by detecting the fluid pressure drop and the dust outflow of the ball bed. Obtain at least one of the following information: internal packing structure of the ball bed, purge gas flow field, motion state of dust particles, and deposition state; Change the simulation parameters and repeat the above steps to perform simulation analysis under different working conditions.

[0006] As an optional implementation, the processing of the ball bed model includes at least one of the following: processing of inter-particle contact points, extension of ball bed inlet and outlet, model cutting, wall processing, extraction of void channels, and setting of particle surfaces; The initial condition parameters of the dust particles include at least one of the following: initial position of the dust particles, initial velocity of the dust particles, density of the dust particles, and particle size distribution of the dust particles.

[0007] As an alternative implementation, computational fluid dynamics calculations and discrete phase model calculations transmit data at the same physical time interval from the moment the calculation of the force effect of the fluid on dust particles begins.

[0008] As an optional implementation, the materials of the particles and dust particles include Li2O, Li2SiO3, Li4SiO4, Li2TiO3, Li4TiO4, LiAlO2, Li2ZrO3, Li2Be2O3, Li8PbO6, xLi4SiO4-yLi2TiO3, and Li4Si z Ti 1- z One or more of O4, wherein 0 ≤ x ≤ 5, 0 ≤ y ≤ 5, 0 ≤ z ≤ 1.

[0009] As an optional implementation, the particle size of the dust particles ranges from 1 to 200 μm, and the dust particles are generated by means of generating dust on the surface of microspheres and generating dust at the gas inlet.

[0010] As an optional implementation, the method further includes analyzing the filtration efficiency of dust particles, wherein the filtration efficiency of dust particles is calculated as follows: , where m out m is the total mass of dust flowing out of the fusion reactor blanket. powder This represents the total mass of dust generated and released.

[0011] As an optional implementation, the purge gas includes one or more of He, Ar, and He+(0.1~1%)H2, and the purge gas pressure ranges from 0.1 to 0.5 MPa.

[0012] Secondly, embodiments of the present invention also provide a simulation system for dust migration and filtration characteristics of a ball bed, comprising: The blanket pebble bed stacking simulation unit is used to simulate the particle stacking process of the fusion reactor blanket pebble bed, form a pebble bed model that meets the requirements, and transmit the final pebble bed model data to the pebble bed carrier gas purging simulation unit through the pebble bed data coupling interface. The pebble bed model data includes at least one of the following: particle coordinates, particle radius, particle material, particle material properties, and pebble bed geometric boundaries.

[0013] The pebble bed carrier gas purging simulation unit is used to simulate and calculate the flow characteristics of tritium purging gas. It regenerates the pebble bed geometry model from the obtained pebble bed model data, processes the model, sets fluid simulation boundary conditions and calculation parameters, convergence conditions, etc., and finally obtains the pebble bed carrier gas purging flow field data for the fusion reactor blanket. This pebble bed carrier gas purging flow field data is then transmitted to the dust motion and deposition simulation unit via a smooth data coupling interface at specific time steps.

[0014] The dust motion and deposition simulation unit is used to simulate and calculate the motion characteristics of dust particles under the blowing of a carrier airflow field, and to determine whether the dust particles are in a captured or rebound state by the adsorption state between the dust particles and the surface of the sphere and the container wall.

[0015] The data extraction and analysis unit is used to process the simulation results of the pebble bed carrier gas purging simulation unit and the dust movement and deposition simulation unit to obtain data such as the internal accumulation structure information of the pebble bed, the purge gas flow field information, the movement state and deposition state of dust particles, and to calculate the filtration efficiency of the pebble bed for radioactive dust particles.

[0016] The results data storage unit is used to store intermediate simulation results from the pebble bed carrier gas purging simulation unit and the dust movement and deposition simulation unit, as well as the final results processed by the data extraction results analysis unit.

[0017] Furthermore, this embodiment of the invention also provides a computer terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-described method for simulating the dust migration and filtration characteristics of a ball bed.

[0018] Finally, this embodiment of the invention also provides a computer-readable medium having a computer program stored thereon, the computer program being executed by a processor to implement the above-described method for simulating the dust migration and filtration characteristics of a ball bed.

[0019] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects: 1. The embodiments of the present invention effectively couple the simulation of particle accumulation in the breeding bed, the simulation of tritium gas purging in the blanket breeding bed, and the simulation of the movement, migration, and deposition of radioactive dust particles through a coupling interface. This enables the simulation of the movement, migration, capture, adsorption, and deposition of radioactive dust in the blanket breeding bed of a fusion reactor. It can replace some experimental assessments, significantly improving the efficiency of blanket design and reducing R&D costs. At the same time, it can obtain more detailed data that cannot be obtained experimentally, such as information on the internal accumulation structure of the breeding bed, information on the purging gas flow field, and the movement and deposition states of dust particles.

[0020] 2. The present invention provides a method for simulating the migration and filtration characteristics of dust in a fusion reactor blanket pebble bed. This method can accurately simulate and analyze the migration and filtration behavior of radioactive dust in the fusion reactor blanket pebble bed with the tritium-generating gas at the particle size of radioactive dust. It obtains more detailed dust migration and filtration characteristic data such as pebble bed carrier gas purging characteristics, dust migration path, dust generation and blowing mass, and dust velocity. It can carry out analysis of radioactive dust migration and filtration characteristics under different blanket pebble beds and service conditions, and can significantly improve the precision and accuracy of the simulation of radioactive dust migration and filtration behavior.

[0021] 3. This invention expands the applicability of existing simulation methods. By changing parameters and physical property data such as the particle accumulation simulation parameters of the blanket breeder bed, the tritium gas purging simulation parameters and purging conditions, the movement and migration of radioactive dust particles, and deposition process conditions, it is possible to easily simulate and analyze the purging, migration, and filtration characteristics of radioactive dust in the tritium-producing zone of a fusion reactor blanket under different types of breeder blankets, different carrier gas purging conditions, and different dust characteristics. This can provide technical guidance for experimental design and significantly reduce experimental and analytical research costs.

[0022] In general, the methods, systems, terminals, and media for simulating the dust migration and filtration characteristics of ball beds provided by the embodiments of the present invention can obtain detailed data on dust migration and filtration characteristics, thereby improving the precision and accuracy of the simulation of radioactive dust migration and filtration behavior. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a method for simulating the dust migration and filtration characteristics of a ball bed according to an embodiment of the present invention; Figure 2 A schematic diagram of a ball bed dust migration filtration characteristic simulation system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a fusion reactor blanket breeder tritium sphere bed model provided in an embodiment of the present invention; Figure 4 This is a simulation diagram of the carrier gas pressure distribution in the breeder bed of the fusion reactor blanket after an embodiment of the present invention. Figure 5 This is a simulated flow diagram of radioactive dust purging and migration from the breeder bed in the fusion reactor blanket, based on an embodiment of the present invention. Figure 6 This is a graph showing the average pressure distribution of the carrier gas section of the fusion reactor blanket breeder sphere after simulation in an embodiment of the present invention. Figure 7 This is a statistical chart showing the amount of radioactive dust generated and emanating from the breeding bed of the fusion reactor blanket after simulation in an embodiment of the present invention. Figure 8 This is a statistical chart showing the mass of radioactive dust generated and the mass of dust flowing out of the breeding bed of the fusion reactor blanket after simulation in an embodiment of the present invention. Figure 9 This is a statistical chart showing the self-filtration efficiency of radioactive dust in the breeding bed of the fusion reactor blanket after simulation in an embodiment of the present invention.

[0025] The attached diagram shows the markings and corresponding component names: 100 - Cladding ball bed accumulation simulation unit, 200 - Ball bed carrier gas purging simulation unit, 300 - Dust movement and deposition simulation unit, 400 - Transfer ball bed data coupling interface, 500 - Transfer smooth data coupling interface, 600 - Data extraction result analysis unit, 700 - Result and data storage unit; 1- Tritium breeder particles, 2- Fusion reactor blanket pebble bed region, 3- Fusion reactor blanket pebble bed carrier gas inlet, 4- Fusion reactor blanket pebble bed carrier gas outlet, 5- Radioactive dust particles, 6- Dust particle flow trace, 7- Descending dust particles, 8- Blowout pebble bed dust particles. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] In the description of this invention, it should be noted that the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Example

[0030] The tritium-producing blanket is a crucial internal component of a fusion reactor, primarily used for breeding tritium fuel. In the tritium-producing region of the blanket, the tritium breeder is formed by stacking spherical particles to create a pebble bed structure. Because the fusion reactor blanket pebble bed must withstand harsh operating environments during service, including high-energy neutron irradiation, high temperatures, thermal expansion, large temperature gradients, and structural wall compression, some particles inevitably break down or pulverize. The resulting dust is radioactive, posing a threat to the integrity of the solid blanket pebble bed structure and the safety of the blanket. Furthermore, the internal flow of the stacked pebble bed's porous structure is extremely complex, with pores at the sub-millimeter level, making it difficult to observe and measure the internal radioactive dust migration characteristics experimentally.

[0031] This embodiment proposes a simulation method for the migration and filtration characteristics of radioactive dust in a fusion reactor blanket pebble bed. This method can accurately simulate and analyze the migration and filtration behavior of radioactive dust within the fusion reactor blanket pebble bed as it travels with tritium-producing gas, significantly improving the precision and accuracy of the simulation. It can easily simulate and analyze the purging, migration, and filtration characteristics of radioactive dust in the tritium-producing zone of the fusion reactor blanket under different fusion reactor blanket types, different carrier gas purging conditions, and different dust characteristics. This method can provide technical guidance for experimental design and significantly reduce experimental and analytical research costs.

[0032] Specifically, refer to Figure 1 As shown, the following three types of coupled calculations are included: (1) The part of the simulation of the accumulation of the cladding proliferating pellets mainly uses the discrete element method (DEM) or rigid body dynamics method (RBD) to simulate the accumulation process of the tritium proliferator particles, and finally obtains the pellet model data of the target parameters.

[0033] (2) The simulation of tritium gas purging in the cladding culture ball bed mainly uses computational fluid dynamics (CFD) to calculate the flow field data of tritium gas in the void inside the cladding ball bed.

[0034] (3) The simulation of the movement, migration and deposition of radioactive dust particles is mainly calculated by using the discrete phase model (DPM) or the discrete element method (DEM) to calculate the migration and deposition of dust particles.

[0035] The data of the ball bed model is transferred to the second part for simulation of the tritium-raising gas purging behavior in the blanket breeding ball bed through the ball bed data coupling interface 400; the data of the tritium-raising gas purging flow field is transferred to the third part for simulation of the movement, migration and deposition process of radioactive dust particles through the smooth data coupling interface 500.

[0036] More specifically, it includes the following steps: S100: Simulation of Particle Accumulation in a Cladding Proliferating Sphere Bed First, parameters such as the ball bed parameters, particle material properties, particle size and distribution are set. Then, particles are gradually added to the ball bed in the calculation area inside the ball bed using the gravity rain method. The particles fall and accumulate in the container at the bottom of the ball bed. When the target height or target number of particles is obtained, particle addition is stopped. The particle accumulation enters the energy dissipation and stable equilibrium stage, and finally the ball bed model data with the target parameters is obtained.

[0037] S200: Data transfer of pebble bed structure The target parameters of the pellet bed model data obtained from the pellet accumulation simulation of the blanket breeding pellet bed are transmitted to the tritium gas purging simulation of the blanket breeding pellet bed through the pellet bed data coupling interface 400.

[0038] S300: Tritium extraction gas purging simulation in a blanket-bringer bed After obtaining the transmitted pebble bed model data, a pebble bed model is built and processed (including processing of inter-particle contact points, extension of pebble bed inlets and outlets, model cutting, wall mattresses, extraction of void channels, and setting of the surface of proliferating particles). Then, the fluid domain in the pores of the pebble bed and the surface of the proliferating particles are meshed. Finally, the boundary conditions for fluid calculation are set, and then numerical solutions are performed to obtain the flow field data of the pebble bed voids.

[0039] S400: Flow field data transmission The tritium-generating gas flow field data inside the blanket breeding bed, obtained from the tritium-generating gas purging simulation, is transferred to the radioactive dust particle motion, migration, and deposition simulation section via the smooth data coupling interface 500. Starting with the calculation of the force effect of the fluid on the dust particles, the CFD calculation and DPM calculation transfer data at the same physical time interval.

[0040] S500: Simulation of the movement and migration of radioactive dust particles within a blanket breeding bed Models of the particles and the ball bed wall are established using the transferred ball bed model. Since the dust particles are much smaller than the tritium breeder microspheres, the particles in the discrete phase model (DPM) are used to represent the discrete dust particles inside the ball bed. First, the dust generation method and initial condition parameters of the dust particles are set. The drag force on the dust particles is calculated using the flow field data solved by CFD. Then, the drag force and gravity results are added to the force situation of the dust particles, and the motion equations of the dust particles are further solved.

[0041] S600: Simulation of radioactive dust particle capture and deposition process in a blanket breeder bed The adsorption state (rebound, capture, etc.) between dust particles and the microsphere wall is analyzed by updating the dust particle information based on their motion state. The adsorption state of the particles is determined according to the set dust particle adsorption and capture probability. Then, the dust particle information is updated and the force situation of the particles is solved again, and this process is repeated iteratively. The calculation end time is determined by detecting the fluid pressure drop and the dust outflow rate at the ball bed outlet.

[0042] S700: Post-processing of calculation results Finally, by post-processing the results, data such as the internal packing structure of the ball bed, the flow field of the purging gas, and the motion and deposition state of dust particles can be obtained.

[0043] By changing the simulation parameters of particle accumulation in the blanket breeder bed, the simulation parameters and purging conditions of tritium-generating gas in the blanket breeder bed, the motion and migration of radioactive dust particles, the simulation parameters of the deposition process, and other parameters and physical properties, and repeating the above steps, simulation analysis of the purging, migration, and filtration characteristics of radioactive dust in the tritium-producing zone of the fusion reactor blanket under different breeder blanket types, different purging conditions, and different dust characteristics can be carried out.

[0044] The materials for the particles and dust particles can be selected from Li2O, Li2SiO3, Li4SiO4, Li2TiO3, Li4TiO4, LiAlO2, Li2ZrO3, Li2Be2O3, Li8PbO6, xLi4SiO4-yLi2TiO3, and Li4Si z Ti 1-z One or more of O4, wherein 0≤x≤5, 0≤y≤5, 0≤z≤1. The particle size range of dust particles is 1~200μm. Dust particles are generated either on the surface of microspheres or at the gas inlet. The dust particle filtration efficiency is calculated as follows: , where m out m is the total mass of dust flowing out of the fusion reactor blanket. powder To generate the total mass of released dust, the purging gas is one or more of He, Ar, and He + (0.1~1%)H2, and the purging gas pressure ranges from 0.1 to 0.5 MPa.

[0045] This invention, through changing parameters and physical properties such as the particle accumulation simulation parameters of the blanket breeder bed, the tritium gas purging simulation parameters and purging conditions within the blanket breeder bed, the movement and migration of radioactive dust particles, and the deposition process simulation parameters, can conduct simulation analysis of the purging, migration, and filtration characteristics of radioactive dust in the tritium-producing zone of a fusion reactor blanket under different breeder blanket types, purging conditions, and dust characteristics. This can provide technical guidance for the design of experimental schemes and significantly reduce experimental and analytical research costs.

[0046] Furthermore, embodiments of the present invention provide a simulation system for the dust migration and filtration characteristics of a ball bed, referring to... Figure 2 As shown, it includes: The blanket pebble bed stacking simulation unit 100 is used to simulate the fusion reactor blanket pebble bed particle stacking process to form a pebble bed model that meets the requirements, and transmits the final pebble bed model data to the pebble bed carrier gas purging simulation unit through the pebble bed data coupling interface 400. The pebble bed model data includes information such as particle coordinates, particle radius, particle material, particle material properties, and pebble bed geometric boundaries.

[0047] The pebble bed carrier gas purging simulation unit 200 is used to simulate and calculate the flow characteristics of tritium purging gas. It regenerates the pebble bed geometry model from the obtained pebble bed model data, processes the model, sets fluid simulation boundary conditions and calculation parameters, convergence conditions, etc., and finally obtains the pebble bed carrier gas purging flow field data for the fusion reactor blanket. This pebble bed carrier gas purging flow field data is then transmitted to the dust motion and deposition simulation unit via the smooth data coupling interface 500 at specific time steps.

[0048] The dust motion and deposition simulation unit 300 is used to simulate and calculate the motion characteristics of dust particles under the blowing of the carrier airflow field, and to determine whether the dust particles are in a captured or rebound state by the adsorption state between the dust particles and the surface of the sphere and the container wall.

[0049] The data extraction and analysis unit 600 is used to process the simulation results of the pebble bed carrier gas purging simulation unit and the dust movement and deposition simulation unit to obtain data such as the internal accumulation structure information of the pebble bed, the purge gas flow field information, the movement state and deposition state of dust particles, and to calculate the filtration efficiency of the pebble bed for radioactive dust particles.

[0050] The method for calculating particulate matter filtration efficiency is as follows: , where m out m is the total mass of dust flowing out of the fusion reactor blanket. powder This represents the total mass of dust generated and released.

[0051] The result data storage unit 700 is used to store intermediate simulation results from the pebble bed carrier gas purging simulation unit and the dust movement and deposition simulation unit, as well as the final results processed by the data extraction result analysis unit.

[0052] Example 1: This embodiment of the invention provides a method for simulating the migration and filtration characteristics of dust particles in a pebble bed. Specifically, it analyzes the migration and filtration characteristics of radioactive dust particles in a real fusion reactor blanket lithium orthosilicate (Li4SiO4) pebble bed, which is a tritium breeding agent. The method includes the following: S100: Simulation of Particle Accumulation in a Cladding Proliferating Sphere Bed First, the parameters of the ball bed (length, width, and height), particle material properties, particle size and distribution, etc., need to be set (see Table 1 below for details). Then, particles are gradually added to the ball bed in the calculation area inside the ball bed using the gravity rain method. The particles fall and accumulate in the container at the bottom of the ball bed. When the target ball bed height or the target number of particles is obtained, the addition of particles is stopped. The particle accumulation enters the energy dissipation and stable equilibrium stage, and finally the ball bed model data with the target parameters is obtained.

[0053] Table 1. Simulation parameters of breeder bed and particle properties in fusion reactor blanket.

[0054] property unit Value Ball court size mm 10d (length) × 10d (width) × 10d (height) <![CDATA[Density of Li4SiO4 / ρ]]> g / ml 2.394 <![CDATA[Particle diameter / d of Li4SiO4]]> mm 1 (Single Size) <![CDATA[Young's modulus / E of Li4SiO4]]> GPa 90 Particle friction coefficient / μpp - 0.1 Particle-wall friction coefficient / μpw - 0.1 coefficient of recovery / e - 0.9 time step / Δt s 1e-7 Particle count - 1200 S200: Data transfer of pebble bed structure The target parameters of the pellet bed model data obtained from the pellet accumulation simulation of the blanket breeding pellet bed are transferred to the tritium gas purging simulation of the blanket breeding pellet bed through the pellet bed data coupling interface 400. This includes the pellet center coordinates (x, y, z), pellet diameter d, pellet bed boundary 10d×10d×10d, and pellet material properties.

[0055] S300: Tritium extraction gas purging simulation in a blanket-bringer bed After obtaining the transmitted Li4SiO4 spherical bed model data, a spherical bed model is built and processed (including processing of inter-particle contact points, extension of spherical bed inlets and outlets, model cutting, wall creation, extraction of void channels, and setting of the surface of proliferating particles, etc.), specifically as follows: Figure 3 As shown, the dimensions of the ball bed area after cutting are 5d×5d×10d, the length of the inlet extension is 5d, and the length of the outlet extension is 15d.

[0056] Then, the fluid domain and the surface of the proliferating particles in the pores of the ball bed are meshed. For example, the surface is meshed with triangular or quadrilateral meshes, and the fluid domain is meshed with tetrahedral, hexahedral, or polyhedral meshes. Finally, the boundary conditions for fluid calculation are set. In this embodiment, the outlet pressure is set to 0.3 MPa, the inlet velocity to 0.1 m / s, and the container sidewall is a sliding wall. A laminar flow model is used for flow calculation, and then numerical solutions are performed to obtain the flow field data of the ball bed pores, such as pressure, velocity, and temperature. Figure 4 The figure shown is a simulation diagram of the carrier gas pressure distribution in the fusion reactor blanket breeder bed after an embodiment of the present invention.

[0057] S400: Flow field data transmission The tritium-generating gas flow field data inside the blanket breeding bed, obtained from the tritium-generating gas purging simulation, is transferred to the radioactive dust particle motion, migration, and deposition simulation section via the smooth data coupling interface 500. Starting with the calculation of the force effect of the fluid on the dust particles, the CFD calculation and DPM calculation transfer data at the same physical time interval.

[0058] S500: Simulation of the movement and migration of radioactive dust particles within a blanket breeding bed Models of the particles and the ball bed wall are established using the transferred ball bed model. Since the dust particles are much smaller than the tritium breeder microspheres, particles from the DPM model are used to represent the discrete dust particles inside the ball bed. First, the dust generation method is defined, such as the dust generation surface (ball bed inlet plane and / or microsphere surface). In this embodiment, the ball bed inlet plane is set as the dust generation surface, and the dust generation rate is 3.5 × 10⁻⁶. -9 The initial conditions of the dust particles include an initial dust velocity of 0 m / s, a dust density of 2.394 g / ml, a minimum dust diameter of 0.001 mm, a maximum dust diameter of 0.02 mm, and an average dust diameter of 0.008 mm. The drag force on the dust particles is calculated using the flow field data obtained by CFD. Then, the drag force and gravity results are added to the force situation of the dust particles, and the motion equation of the dust particles is further solved.

[0059] Within the Lagrange framework, the governing equations for the mass, velocity, angular velocity, and temperature of dust particles are as follows:

[0060] The motion of dust particles is solved based on Newton's second law. Where m... i For the mass of dust particles, v i For the velocity of dust particles, ω i T is the angular velocity of the dust particles. p,i Let C be the temperature of the dust particles, t be the solution time step, and C be the temperature of the dust particles. p,i For hot melting, I i Let be the moment of inertia of the dust particles, and g be the acceleration due to gravity. 𝑖 This represents the change in particle mass caused by a phase transition; under conditions where no phase transition is involved, this term is 0; 𝑓 d,𝑖 The drag force exerted by the gas on the particles, 𝑓 𝑝,𝑖 For pressure gradient force, 𝑓 𝑐,𝑖 For interparticle collision force, 𝑓 𝑜𝑡ℎ𝑒𝑟 Other forces, including buoyancy and illusory mass forces, etc. 𝑖 The torque experienced by the particle; 𝑞 𝑓𝑝,𝑖 , 𝑞 𝑝𝑝,𝑖 , 𝑞 𝑝𝑐,𝑖 These represent interphase convective heat transfer, particle conduction, and phase change heat transfer, respectively. They can be set to constant values ​​if heat transfer is not considered.

[0061] like Figure 5The diagram shown is a streamline diagram of radioactive dust purging and migration in the breeder bed of a fusion reactor blanket after simulation according to an embodiment of the present invention. The initial condition parameters of the dust particles include at least one of the following: the initial position of the dust particles is the inlet plane of the sphere bed; the initial velocity of the dust particles is 0 m / s; the density of the dust particles is 2.394 g / ml; and the particle size distribution of the dust particles (minimum diameter is 0.001 mm, maximum diameter is 0.02 mm, and average diameter is 0.008 mm).

[0062] S600: Simulation of radioactive dust particle capture and deposition process in a blanket breeder bed The adsorption state of particles is randomly determined by updating the dust particle information based on the motion state and setting the dust particle adsorption and capture probability. In this embodiment, the capture probabilities set for different cases are 0%, 10%, 30%, 50%, 70%, 90%, and 100%, respectively. Then, the dust particle information is updated again, and the particle force situation is solved again, and this process is iterated continuously. The calculation end time is determined by detecting the residuals of the fluid pressure drop and the dust outflow from the ball bed outlet. In this embodiment, the residuals of all variables are set to be less than 1 × 10⁻⁶. -6 The calculation ends when the time is right.

[0063] S700: Post-processing of calculation results Finally, by exporting dust and flow field data, drawing streamline diagrams, and performing cross-sectional averaging, post-processing can yield data such as the internal packing structure of the pebble bed, the purge gas flow field, and the motion and deposition states of dust particles. For example... Figure 6 The figure shows the cross-sectional average pressure distribution curve of the carrier gas in the fusion reactor blanket breeder bed after post-processing, as simulated in an embodiment of the present invention. Figure 7 The figure shown is a statistical chart of the amount of radioactive dust generated and the amount of dust flowing out of the breeding bed of the fusion reactor blanket after simulation in an embodiment of the present invention. Figure 8 The figure shown is a statistical chart of the mass of radioactive dust generated and the mass of dust flowing out of the breeding bed of the fusion reactor blanket after simulation in an embodiment of the present invention. Figure 9 The figure shows the self-filtration efficiency of radioactive dust in the breeding sphere bed of the fusion reactor blanket after simulation in an embodiment of the present invention.

[0064] Depend on Figure 6 It can be seen that at the inlet, the fluid encounters the greatest resistance and the highest pressure when entering the ball bed. As the airflow penetrates deeper into the ball bed, the pressure gradually decreases, possibly because the resistance encountered by the airflow gradually decreases as it passes through the pores between the particles. Furthermore, different inlet carrier gas velocities affect the pressure distribution; higher velocities correspond to higher pressure drop rates.

[0065] Depend on Figure 7It can be seen that as the adsorption and capture probability increases, the amount of dust escaping from the ball bed decreases, indicating that a higher adsorption and capture probability helps reduce dust escape. The number of particles generated per day is the highest across all particle sizes. As the particle size increases, the number of escaping particles decreases rapidly, indicating that smaller dust particles are more easily blown out of the ball bed. When the adsorption and capture probability reaches 100%, almost no dust escapes, indicating that under ideal conditions, all dust can be captured.

[0066] Depend on Figure 8 It can be seen that the daily generated particle mass is the highest for all particle sizes, and reaches a peak at a particle size of about 7 μm. After that, it decreases with the increase of particle size. As the adsorption and capture probability increases, the mass of dust flowing out of the ball bed decreases significantly. When the adsorption and capture probability reaches 100%, the mass of dust flowing out of the ball bed is almost zero, indicating that all dust is effectively captured.

[0067] Depend on Figure 9 It can be seen that the filtration efficiency increases linearly with the increase of the adsorption capture probability, which indicates that increasing the adsorption capture probability can significantly improve the filtration efficiency. When the adsorption capture probability reaches 100%, the filtration efficiency is close to 0.915, indicating that the filtration efficiency is very high under ideal conditions.

[0068] Therefore, by referring to the research of the embodiments of the present invention, by optimizing the geometric and operational parameters of the pellet bed, such as the purging air inlet direction and the inlet carrier gas velocity, and by increasing the adsorption and capture probability, the migration and deposition of radioactive dust can be effectively controlled, thereby improving the operational safety and efficiency of the fusion reactor blanket breeder pellet bed.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention. It should be noted that the structures or components illustrated in the accompanying drawings are not necessarily drawn to scale, and descriptions of well-known components, processing techniques, and processes have been omitted to avoid unnecessarily limiting the invention.

Claims

1. A method of simulating the dust migration filtration properties of a pebble bed, characterized in that, The method comprises the following steps: Setting the ball bed geometric parameters, particle material attribute parameters, particle size parameters and particle size distribution parameters, gradually adding particles in the ball bed through gravity rain method in the internal calculation area of the ball bed, and the particles are stacked in the container at the bottom of the ball bed, and the particle addition is stopped when the target height or target number of particles is obtained, and the ball bed model data of the target parameters is obtained; According to the obtained ball bed model data, the ball bed model is established, the ball bed model is processed, and then the fluid domain in the ball bed pore and the particle surface are divided into grids, the fluid calculation boundary condition is set, and the numerical solution is obtained to obtain the ball bed gap flow field data; According to the ball bed model, the particle and ball bed wall surface model are established, the particle represents the dispersed dust particles in the ball bed, the dust particle generation mode and the dust particle initial condition parameters are set, the drag force of the dust particles is calculated through the flow field data calculated by the computational fluid dynamics, and then the drag force and gravity are added to the force condition of the dust particles, and the dust particle motion equation is solved; The adsorption state between the dust particles and the particle wall surface is analyzed through the updated dust particle information, the adsorption state of the particles is determined according to the set dust particle adsorption capture probability, the dust particle information is updated and the force condition of the particles is solved again, and the iteration is continuously carried out, and the end time is determined by detecting the fluid pressure drop and the ball bed dust outflow amount; At least one of the following information is obtained: the ball bed internal stacking structure information, the swept gas flow field information, the motion state of the dust particles and the deposition state of the dust particles. The simulation parameters are changed, and the above steps are repeated to analyze the simulation under different conditions.

2. The method of claim 1, wherein, The processing of the ball bed model includes at least one of the following: particle contact point processing, ball bed inlet and outlet extension, model cutting, wall surface processing, void flow channel extraction, and particle surface setting. The dust particle initial condition parameters include at least one of the following: initial position of the dust particle, initial velocity of the dust particle, density of the dust particle, and particle size distribution of the dust particle.

3. The method according to any one of claims 1-2, wherein, The data is transmitted at the same physical time interval from the moment when the fluid starts to calculate the force acting on the dust particles to the moment when the computational fluid dynamics calculation and the discrete phase model calculation are performed.

4. The method of claim 3, wherein, The material of the particles and dust particles includes one or more of Li2O, Li2SiO3, Li4SiO4, Li2TiO3, Li4TiO4, LiAlO2, Li2ZrO3, Li2Be2O3, Li8PbO6, xLi4SiO4-yLi2TiO3, Li4Si z Ti 1-z O4, where 0 ≤ x ≤ 5, 0 ≤ y ≤ 5, 0 ≤ z ≤ 1.

5. The method of claim 1, wherein, The particle size range of the dust particles is 1-200 μm, and the particle size generation mode of the dust particles includes generating dust on the surface of the microsphere or generating dust at the gas inlet.

6. The method of claim 1, wherein, The method further comprises analyzing the dust particle filtration efficiency, and the calculation method of the dust particle filtration efficiency is: where m out is the total mass of dust flowing out of the blanket of the fusion reactor, m powder is the total mass of dust generated by the release.

7. The method of claim 1, wherein, The sweeping gas includes one or more of He, Ar, He+(0.1-1%) H2, and the sweeping gas pressure range is 0.1-0.5 MPa.

8. A simulation system for the dust migration filtration characteristics of a pebble bed, characterized in that, The method comprises: The cladding ball bed stacking simulation unit (100) is used to simulate the ball bed particle stacking process of the fusion reactor cladding, form a ball bed model meeting the requirements, and transmit the final ball bed model data to the ball bed carrier gas sweeping simulation unit through the transmission ball bed data coupling interface (400). The ball bed model data includes at least one of the following information: particle coordinates, particle radius, particle material, particle material performance, and ball bed geometric boundary. The ball bed carrier gas purging simulation unit (200) is used for simulating the flow characteristics of tritium purging gas, regenerating the ball bed geometric model and model processing, setting the fluid simulation boundary conditions and calculation parameters, and convergence conditions based on the obtained ball bed model data, and finally obtaining the fusion reactor blanket ball bed carrier gas purging flow field data. The ball bed carrier gas purging flow field data is transmitted to the dust motion deposition simulation unit through the transfer flow data coupling interface (500) according to a specific time step. The dust motion deposition simulation unit (300) is used for simulating the motion characteristics of dust particles under the purging of the carrier gas flow field, and determining whether the dust particles are in a capture state or a rebound state through the adsorption state between the dust particles and the surface of the small ball and the container wall. The data extraction result analysis unit (600) is used for data processing of the simulation results of the ball bed carrier gas purging simulation unit and the dust motion deposition simulation unit, obtaining the ball bed internal accumulation structure information, the purging gas flow field information, the motion state and the deposition state of the dust particles, and calculating the filtration efficiency of the ball bed to the radioactive dust particles. The result data storage unit (700) is used for storing the intermediate results of the simulation of the ball bed carrier gas purging simulation unit and the dust motion deposition simulation unit, and the final results processed by the data extraction result analysis unit.

9. A computer terminal, characterized in that The computer program is executed by the processor to realize the ball bed dust migration filtration characteristic simulation method according to any one of claims 1-7.

10. A computer readable medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the ball bed dust migration filtration characteristic simulation method according to any one of claims 1-7.

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