A method, apparatus and storage medium for determining the diffusion migration motion of radioactive aerosols.

Abstract

This invention relates to a method, apparatus, and storage medium for determining the diffusion migration motion of radioactive aerosols. The method involves acquiring the total duration of an accident and the initial spatial distribution of aerosol particles; dividing the total duration into multiple time steps, dividing the containment's computational domain into multiple computational domain nodes, and dividing the aerosol particles into multiple particle size ranges; selecting a first time step and iteratively calculating the multiple computational domain nodes within the containment to obtain thermo-hydraulic parameters; performing force balance calculations on the aerosol particles to obtain their diffusion migration motion; updating the initial spatial distribution of the aerosol particles to obtain their target spatial distribution; and traversing the thermo-hydraulic parameters and target spatial distributions corresponding to multiple time steps to determine the motion result of the radioactive aerosols. This invention achieves refined spatial division, resulting in a more accurate assessment of the vapor condensation and removal rate of aerosols under containment cooling conditions.

Description

Technical Field

[0001] This invention relates to the technical field of nuclear emergency response, and in particular to a method, apparatus, and storage medium for determining the diffusion migration of radioactive aerosols. Background Technology

[0002] Following a nuclear accident, third-generation nuclear power plants release large amounts of high-temperature water vapor and radioactive aerosols into the containment vessel. Third-generation nuclear power plants possess excellent heat removal capabilities; cooling causes water vapor to condense on the walls of the containment's heat exchangers, thereby removing radioactive aerosols and preventing further radioactive material leakage. Therefore, assessing the rate of aerosol vapor condensation and removal under containment cooling conditions is crucial for the assessment of radioactive source terms in passive containment systems and for safety design.

[0003] In the event of an accident, the assessment of aerosol removal rates within the containment space is typically conducted using theoretical models based on numerous simplified assumptions. In terms of experimental analysis, current diffusion-coating methods are mostly focused on a single spatial homogeneity parameter.

[0004] However, the environment inside the containment under actual cooling conditions is very complex. The combined effect of steam condensation on aerosol removal is strong. Moreover, the diffusion migration of aerosol particles under actual conditions is directly related to the water vapor condensation state of the wall and is not a single spatial distribution. Current experimental homogenization analysis methods are difficult to describe the diffusion migration effect when the distribution of thermal-hydraulic parameters is uneven. The lack of spatial refinement leads to errors in the assessment of the steam condensation removal rate of aerosols under containment cooling conditions.

[0005] The above problems urgently need to be addressed. Summary of the Invention

[0006] This invention discloses a method, apparatus, and storage medium for determining the diffusion motion of radioactive aerosols, aiming to solve the technical problems existing in the prior art.

[0007] The present invention adopts the following technical solution:

[0008] On one hand, the present invention provides a method for determining the diffusion migration motion of radioactive aerosols, comprising: acquiring the total duration from the start to the end of an accident, and the initial spatial distribution of aerosol particles within the containment during the accident; dividing the total duration into multiple time steps, dividing the computational domain of the containment into multiple computational domain nodes, and dividing the aerosol particles into multiple particle size intervals; selecting a first time step, iteratively calculating the multiple computational domain nodes within the containment to obtain the thermo-hydraulic parameters corresponding to the first time step, wherein the first time step is the current time step among the multiple time steps; performing force balance calculations on the aerosol particles corresponding to the multiple particle size intervals based on the thermo-hydraulic parameters to obtain the diffusion migration motion of the aerosol particles; updating the initial spatial distribution of the aerosol particles based on the diffusion migration motion to obtain the target spatial distribution of the aerosol particles; traversing the thermo-hydraulic parameters corresponding to the multiple time steps and the target spatial distribution of the aerosol particles corresponding to the multiple time steps to determine the motion result of unsteady radioactive aerosols in the computational domain of the containment.

[0009] Optionally, selecting a first time step and iteratively calculating the multiple computational domain nodes within the containment to obtain the corresponding thermo-hydraulic parameters for the first time step includes: at the multiple computational domain nodes, solving for the airflow motion in the computational domain within the containment based on the transport equations of the Eulerian system; calculating the mixed flow of the accident water vapor source term and air based on a fluid dynamics component transport model, wherein the accident water vapor source term is used to indicate the quantity, temperature, and pressure of water vapor released from the containment source under accident conditions; and simplifying the mass and heat transfer model based on the airflow motion and the mixed flow to obtain the thermo-hydraulic parameters, wherein the mass and heat transfer model is used to indicate the condensation process of water vapor on the walls of the containment.

[0010] Optionally, the step of simplifying the mass and heat transfer model based on the airflow motion and the mixed flow to obtain the thermal-hydraulic parameters includes: determining the partial pressure of water vapor within the containment; when the partial pressure of water vapor reaches the condensation critical point, obtaining the mass transfer flow rate based on the mass and heat transfer model, wherein the mass transfer flow rate indicates the amount of mass reduction of water vapor components caused by the condensation process of water vapor on the wall; obtaining the heat transfer flow rate based on the mass and heat transfer model and the mass transfer flow rate, wherein the heat transfer flow rate indicates the amount of heat transfer caused by the condensation process of water vapor on the wall; and solving the thermal-hydraulic parameters by coupling the mass transfer flow rate and the heat transfer flow rate with the airflow motion and the mixed flow.

[0011] Optionally, determining the partial pressure of water vapor within the containment includes: determining the partial pressure of water vapor based on the Clapeyron equation; the Clapeyron equation is calculated as follows:

[0012]

[0013] Where p is the partial pressure of water vapor, T is the temperature inside the heat trap device connected to the containment, and ΔH is... vap R is the latent heat of vaporization of water vapor, and R is the gas constant.

[0014] Optionally, obtaining the mass transfer flow rate based on the mass and heat transfer model includes: determining the mass transfer flow rate based on the condensation formula; the condensation formula is calculated as follows:

[0015]

[0016] Where, q m For mass transfer flow rate, W s ρ is the mass fraction of water vapor, D is the effective mass diffusion coefficient, v is the volume of water vapor, and n is the quantity concentration of the water vapor source term mixed with air in the accident.

[0017] Optionally, obtaining the heat transfer flow rate based on the mass and heat transfer model and the mass transfer flow rate includes: determining the heat transfer flow rate based on the condensation heat flow formula; the condensation heat flow formula is calculated as follows:

[0018] H m =q m h s

[0019] Among them, H m For heat transfer flow rate, q m For mass transfer flow rate, h s This represents the saturated vapor specific enthalpy at the corresponding pressure.

[0020] Optionally, the step of performing force balance calculations on the aerosol particles corresponding to the multiple particle size ranges based on the thermal-hydraulic parameters to obtain the diffusion migration motion of the aerosol particles includes: constructing force balance equations for the aerosol particles in a Lagrangian system based on the thermal-hydraulic parameters; determining the modal region in which the aerosol particles are located, wherein the modal region is used to indicate the motion state of the aerosol particles; determining the diffusion migration force corresponding to the aerosol particles in the modal region, wherein the diffusion migration force is used to indicate the force by which the aerosol particles are swept towards the wall by the flow formed by the water vapor in the condensation process; and obtaining the diffusion migration motion of the aerosol particles based on the diffusion migration force.

[0021] Optionally, the step of constructing force equilibrium equations for aerosol particles in a Lagrangian system based on thermal-hydraulic parameters includes: obtaining the motion of aerosol particles in the flow field; constructing force equilibrium equations for aerosol particles; and calculating the force equilibrium equations as follows:

[0022]

[0023] in, F is the inertial force of the aerosol particles. D (uu p ) is the drag force. F is the difference between gravity and buoyancy. a u is the diffusing force of the aerosol particles. p Let u be the velocity of the aerosol particles, and ρ be the gas velocity. p ρ is the density of the aerosol particles, and ρ is the gas density.

[0024] Optionally, determining the modal region of the aerosol particles includes: determining the flow state of the water vapor during the condensation process based on the particle flow equation; determining the modal region based on the flow state, wherein when the flow state is greater than a first preset value, the aerosol particles are in a free molecular state; when the flow state is equal to a second preset value, the aerosol particles are in a transition region; and when the flow state is less than the second preset value, the aerosol particles are in a slip region, wherein the first preset value is greater than or equal to the second preset value; wherein the particle flow equation is calculated as follows:

[0025]

[0026] Among them, K n The flow state is given by λ, where λ is the mean free path of the mixture of the accident water vapor source term and air; d p The diameter of the aerosol particles is denoted as .

[0027] Optionally, when the modal region is a slip region, determining the diffusion force of the aerosol particles within the modal region includes: calculating the diffusion force of the aerosol particles within the slip region as follows:

[0028]

[0029] Where: SD is the slip region, η is the viscosity of the mixed gas, R0 is the radius of the aerosol particles, and σ 12 The ratio of the diameter to the mass of the gas mixture. D represents the gradient of the molar composition of water vapor. 12 F is the diffusion coefficient. SD ∈F a .

[0030] Optionally, when the modal region is a transition region, determining the diffusion force of the aerosol particles within the modal region includes: calculating the diffusion force of the aerosol particles within the transition region as follows:

[0031]

[0032] Where D is the transition region, R is the radius of the aerosol particles, n is the number concentration of the gas mixture, m1 is the molecular mass of water vapor, m2 is the molecular mass of the non-condensable gas, k is the Boltzmann constant, and T is the temperature inside the heat trap device connected to the containment structure. D represents the gradient of the molar composition of water vapor. 12 F is the diffusion coefficient. D ∈F a .

[0033] According to another aspect of the present invention, a device for determining the diffusion migration motion of radioactive aerosols is also provided, comprising: an acquisition module, configured to acquire the total duration from the start of an accident to the end of the accident, and the initial spatial distribution of aerosol particles within the containment during the accident; a division module, configured to divide the total duration into multiple time steps, divide the computational domain of the containment into multiple computational domain nodes, and divide the aerosol particles into multiple particle size ranges; and a thermo-hydraulic parameter determination module, configured to select a first time step, iteratively calculate the multiple computational domain nodes within the containment, and obtain the thermo-hydraulic parameters corresponding to the first time step, wherein the first time step... The step is the current time step among the multiple time steps; the diffusion migration motion determination module is used to perform force balance calculations on the aerosol particles corresponding to the multiple particle size ranges based on the thermal-hydraulic parameters to obtain the diffusion migration motion of the aerosol particles; the update module is used to update the initial spatial position distribution of the aerosol particles based on the diffusion migration motion to obtain the target spatial position distribution of the aerosol particles; the motion result module is used to traverse the thermal-hydraulic parameters corresponding to the multiple time steps and the target spatial position distribution of the aerosol particles corresponding to the multiple time steps to determine the motion result of the unsteady radioactive aerosols in the containment calculation domain.

[0034] According to another aspect of the present invention, a non-volatile storage medium is also provided, the non-volatile storage medium storing a plurality of instructions adapted for loading by a processor and executing any one of the radioactive aerosol diffusion migration motion determination methods.

[0035] According to another aspect of the present invention, a computer program product is also provided, including a computer program that, when executed by a processor, implements the steps of the method for determining the radioactive aerosol diffusion migration as described in any one of the present invention.

[0036] The technical solution adopted in this invention can achieve at least one of the following beneficial effects:

[0037] In this embodiment of the invention, the total duration from the start to the end of the accident, and the initial spatial distribution of aerosol particles within the containment during the accident are obtained; the total duration is divided into multiple time steps, the computational domain of the containment is divided into multiple computational domain nodes, and the aerosol particles are divided into multiple particle size ranges; a first time step is selected, and iterative calculations are performed on the multiple computational domain nodes within the containment to obtain the thermo-hydraulic parameters corresponding to the first time step, wherein the first time step is the current time step among the multiple time steps; based on the thermo-hydraulic parameters, force balance calculations are performed on the aerosol particles corresponding to the multiple particle size ranges to obtain the diffusion migration motion of the aerosol particles; based on the diffusion migration motion, the aerosol particles are updated. The initial spatial position distribution of the particles is obtained to determine the target spatial position distribution of the aerosol particles. By traversing the thermal-hydraulic parameters corresponding to the multiple time steps and the target spatial position distribution of the aerosol particles corresponding to the multiple time steps, the motion result of the unsteady radioactive aerosols in the containment computational domain is determined. This achieves the purpose of dividing the time, containment computational domain, and aerosol particle interval, and performing refined analysis on multiple containment computational domains and aerosol particle intervals within each time step. This achieves the technical effect of more accurate evaluation of the vapor condensation removal rate of aerosols under containment cooling conditions through refined spatial division, thereby solving the technical problem of errors in the evaluation of the vapor condensation removal rate of aerosols under containment cooling conditions due to insufficient spatial refinement. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 This is a flowchart of a method for determining the diffusion motion of radioactive aerosols according to Embodiment 1 of the present invention;

[0040] Figure 2 This is a distribution diagram of the computational domain nodes within the containment of a method for determining the diffusion and sludge motion of radioactive aerosols in Embodiment 1 of the present invention.

[0041] Figure 3 This is a water vapor concentration distribution diagram of a method for determining the motion of radioactive aerosol diffusion phoresis in Embodiment 1 of the present invention;

[0042] Figure 4 This is a force diagram of aerosol particles in a method for determining the diffusion motion of radioactive aerosols according to Embodiment 1 of the present invention.

[0043] Figure 5 This is a flowchart of an optional method for determining the diffusion motion of radioactive aerosols in Embodiment 2 of the present invention;

[0044] Figure 6 This is a schematic diagram of a radioactive aerosol diffusion migration determination device according to Embodiment 3 of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a magnetic connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, "a plurality of" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0047] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] First, to facilitate understanding of the embodiments of the present invention, some terms or nouns involved in the present invention will be explained below:

[0049] Radioactive aerosols are dispersion systems formed by solid or liquid particles containing radioactive nuclides suspended in the air or other gases.

[0050] Diffusion migration refers to the net motion of particles caused by the uneven distribution of gas molecules. When a concentration gradient exists in a gaseous medium, the diffusion rate of matter in one direction will be significantly greater than that in other directions, causing particles to move in the same direction as the diffusion due to the impact of diffusing molecules.

[0051] To address the problems existing in the prior art, embodiments of this application provide a method, apparatus, and storage medium for determining the motion of radioactive aerosol diffusion phoresis.

[0052] Example 1

[0053] This embodiment provides a method for determining the diffusion migration motion of radioactive aerosols, such as... Figure 1 As shown, Figure 1 This is a flowchart of a method for determining the diffusion migration motion of radioactive aerosols according to Embodiment 1 of the present invention. The method includes:

[0054] Step S102: Obtain the total duration from the start of the accident to the end of the accident, as well as the initial spatial distribution of aerosol particles inside the containment during the accident.

[0055] Optionally, a nuclear accident can occur within the reactor core. During a nuclear accident, some radioactive aerosol particles are generated. These aerosol particles diffuse into the containment vessel, where they are collected to prevent them from spreading to the external environment and causing radioactive damage to personnel on site.

[0056] Optionally, the time from the start to the end of a nuclear reaction accident is defined as the accident occurrence time. During the accident occurrence time, it is necessary to determine the movement process of the diffused aerosol particles in order to infer whether the aerosol particles have been completely removed, and then to conduct a passive containment radioactive source term assessment and safety design.

[0057] Step S104: Divide the total duration into multiple time steps, divide the computational domain of the containment into multiple computational domain nodes, and divide the aerosol particles into multiple particle size ranges.

[0058] Optionally, the computational domain partitioning of the containment should ensure that the nodes of the partitioned computational domains are densified in the areas where diffusion migration mainly occurs, and should be judged according to appropriate criteria to ensure the applicability of the subsequent wall model. Specifically, after an accident, a large amount of water vapor is generated and condenses on the walls of the containment. The condensed water vapor will remove aerosol particles; therefore, the applicability of the wall model is equivalent to the applicability of the computational domain of the containment. Figure 2 As shown, Figure 2 This is a distribution diagram of the computational domain nodes within the containment of a method for determining the diffusion migration motion of radioactive aerosols according to Embodiment 1 of the present invention.

[0059] Optionally, the judgment criterion is to determine the applicability of the wall model based on the wall y+ value judgment criterion, ensuring that each selected wall model has a suitable application range. The specific wall y+ value judgment criterion is as follows:

[0060]

[0061] Where y is the distance from a point on the boundary layer to the wall, and u τ Here, ρ represents the near-wall friction velocity, and v represents the kinematic viscosity. It's important to note that the boundary layer refers to a fluid layer with a significant velocity gradient that forms near the solid wall surface when water vapor flows through it, due to fluid viscosity. The velocity of water vapor within the boundary layer gradually increases with distance from the wall until it reaches the mainstream velocity. The thickness of the boundary layer is a crucial parameter describing its characteristics; it represents the distance from the wall to the point where the velocity reaches 99% of the mainstream velocity.

[0062] Optionally, the computational domain node partitioning process and the total time partitioning process need to perform node independence verification and time step independence verification. Node independence verification primarily assesses the sensitivity of the computational results to the density of nodes in the computational domain. In numerical computation, the density of nodes in the computational domain directly affects the accuracy and efficiency of the computational results. Time step independence verification assesses the sensitivity of the computational results to the size of the time step. In transient computation, the selection of the time step affects the convergence and accuracy of the computation.

[0063] Specifically, the node independence verification process typically includes: Changing node density: Observing changes in computational results by continuously altering the density of nodes in the computational domain, i.e., increasing or decreasing the number of nodes. Evaluating result changes: Analyzing the differences in computational results under different node densities in the computational domain. If the differences are within acceptable limits, the computational results are considered independent of the node density, meaning the influence of node density on the computational results is negligible. Determining the optimal node density: Under the premise of meeting computational accuracy requirements, selecting the computational domain node density with the highest computational efficiency as the final criterion for partitioning the computational domain nodes.

[0064] Specifically, the process of verifying time step independence typically includes: selecting different time steps: while keeping other calculation parameters constant, performing calculations at different time steps. Observing the calculation results: analyzing the differences in calculation results under different time steps, paying particular attention to parameters and physical quantities that are sensitive to time step. Determining a reasonable time step: while ensuring the accuracy and stability of the calculation results, selecting a time step that is neither too large nor too small to balance calculation accuracy and calculation efficiency.

[0065] Optionally, the aerosol can be divided into different particle size ranges based on the source term particle size distribution density function. The actual source term particle size distribution is fitted using a probability density function, which can be either a log-normal distribution function or a Rosin-Rammler distribution function.

[0066] Step S106: Select the first time step, perform iterative calculations on multiple computational domain nodes within the containment to obtain the thermal-hydraulic parameters corresponding to the first time step, wherein the first time step is the current time step among multiple time steps;

[0067] In some preferred embodiments, a first time step is selected, and iterative calculations are performed on multiple computational domain nodes within the containment to obtain the corresponding thermo-hydraulic parameters for the first time step. This includes: at multiple computational domain nodes, solving for the airflow motion in the computational domain within the containment based on the transport equations of the Eulerian system; calculating the mixed flow of the accident water vapor source term and air based on the component transport model of fluid mechanics, wherein the accident water vapor source term is used to indicate the quantity, temperature, and pressure of water vapor released from the source of the containment under accident conditions; and simplifying the mass and heat transfer model based on the airflow motion and mixed flow to obtain the thermo-hydraulic parameters, wherein the mass and heat transfer model is used to indicate the condensation process of water vapor on the walls of the containment.

[0068] Optionally, the transport equations of the Eulerian system are used to solve for the airflow motion in the containment computational domain at each computational domain node location. Specifically, solving for the airflow motion involves applying the general fluid conservation equations of computational fluid dynamics. The mixed flow of the accident water vapor source term with air is determined using the component transport equations of computational fluid dynamics.

[0069] Optionally, the purpose of simplifying the mass and heat transfer model is to calculate the condensation of high-temperature, high-pressure water vapor at the wall surface in the heat trap environment connected to the containment, providing input for aerosol diffusion calculations. The specific method for simplifying the mass and heat transfer model is to ignore the droplets generated by the condensation process of water vapor upon encountering cooling, and only consider the reduction in water vapor component mass and the resulting heat transfer process caused by the condensation process near the wall surface, thereby simplifying the mass and heat transfer model.

[0070] It should be noted that the condensation process near the wall refers to water vapor condensing only at the first layer of nodes near the wall. The first layer of nodes refers to the first computational domain node adjacent to the wall and exchanging heat with it. This computational domain node is located at the interface between the fluid and the wall. Specifically, when water vapor flows over a cold wall, it undergoes a phase change near the wall, transforming from a gaseous state to a liquid state—the condensation process. The temperature, pressure, humidity, and other parameters of the first computational domain node change as the condensation process proceeds, thus affecting the flow field and temperature field of the entire computational domain. Figure 3 As shown, Figure 3 This is a water vapor concentration distribution diagram from an embodiment 1 of the present invention, illustrating a method for determining the diffusion migration of radioactive aerosols. It should be noted that... Figure 3 for Figure 2 Water vapor concentration distribution in the area circled in the middle rectangle.

[0071] In some preferred embodiments, based on airflow motion and mixed flow, a simplified mass and heat transfer model is used to obtain thermohydraulic parameters, including: determining the partial pressure of water vapor within the containment; when the partial pressure of water vapor reaches the condensation critical point, obtaining the mass transfer flow rate based on the mass and heat transfer model, wherein the mass transfer flow rate is used to indicate the amount of mass reduction of water vapor components caused by the condensation process of water vapor at the wall; obtaining the heat transfer flow rate based on the mass and heat transfer model and the mass transfer flow rate, wherein the heat transfer flow rate is used to indicate the amount of heat transfer caused by the condensation process of water vapor at the wall; and solving the thermohydraulic parameters by coupling the mass transfer flow rate and the heat transfer flow rate with airflow motion and mixed flow.

[0072] Optionally, the reduction in water vapor mass caused by condensation near the wall needs to be determined by assessing whether the partial pressure of the water vapor reaches the condensation critical point, i.e., determining the saturated vapor pressure of the water vapor at the heat trap temperature. A higher partial pressure indicates that pressure is generated within the containment vessel, causing water vapor molecules to move faster and thus more easily collide with the wall surface, leading to condensation. A lower partial pressure suggests that the water vapor may not be rapidly impacting the wall surface, resulting in no condensation. The reduction in water vapor mass caused by condensation near the wall requires calculating the mass transfer flow rate of water vapor condensation. It should be noted that the mass transfer flow rate calculation method ignores heat transfer through the condensate film, considering only convective and condensation mass transfer. During the heat transfer process generated by the condensation near the wall, the reduction in water vapor mass (after condensation into a liquid state, resulting in a decrease in water vapor volume) requires calculating the condensation heat flow.

[0073] In some preferred embodiments, determining the partial pressure of water vapor within the containment includes: determining the partial pressure of water vapor based on the Clapeyron equation; the Clapeyron equation is calculated as follows:

[0074]

[0075] Where p is the partial pressure of water vapor, T is the temperature inside the heat trap connected to the containment, and ΔH is... vap R is the latent heat of vaporization of water vapor, and R is the gas constant.

[0076] In some preferred embodiments, the mass transfer flow rate is obtained based on the mass and heat transfer model, including: determining the mass transfer flow rate based on the condensation formula; the condensation formula is calculated as follows:

[0077]

[0078] Where, q m For mass transfer flow rate, W s ρ is the mass fraction of water vapor, D is the effective mass diffusion coefficient, v is the volume of water vapor, and n is the quantity concentration of the water vapor source term mixed with air in the accident.

[0079] In some preferred embodiments, the heat transfer flow rate is obtained based on the mass and heat transfer model and the mass transfer flow rate, including: determining the heat transfer flow rate based on the condensation heat flow formula; the condensation heat flow formula is calculated as follows:

[0080] H m =q m h s

[0081] Among them, H m For heat transfer flow rate, q m For mass transfer flow rate, h s This represents the saturated vapor specific enthalpy at the corresponding pressure.

[0082] Step S108: Based on the thermal-hydraulic parameters, force balance calculations are performed on aerosol particles corresponding to multiple particle size ranges to obtain the diffusion migration motion of aerosol particles.

[0083] In some preferred embodiments, force balance calculations are performed on aerosol particles corresponding to multiple particle size ranges based on thermohydraulic parameters to obtain the diffusion migration motion of the aerosol particles. This includes: constructing force balance equations for the aerosol particles in a Lagrangian system based on thermohydraulic parameters; determining the modal region in which the aerosol particles are located, wherein the modal region is used to indicate the motion state of the aerosol particles; determining the diffusion migration force corresponding to the aerosol particles in the modal region, wherein the diffusion migration force is used to indicate the force by which the aerosol particles are swept towards the wall by the flow formed by the water vapor in the condensation process; and obtaining the diffusion migration motion of the aerosol particles based on the diffusion migration force.

[0084] Optionally, within the Lagrangian framework, a force equilibrium model of aerosol particles is constructed. Specifically, this involves tracking the motion of individual aerosol particles in the flow field, establishing force equilibrium equations for the aerosol particles, considering the diffusing force, drag force, and inertial force acting on them in the flow field, and calculating the impact of changes in the thermal-hydraulic environment on the aerosol particle motion, thus achieving mechanistic calculations. Based on these mechanistic calculations, the diffusing motion process of aerosol particles can be obtained. For example... Figure 4 As shown, Figure 4 This is a force diagram of aerosol particles in a method for determining the diffusion motion of radioactive aerosols according to Embodiment 1 of the present invention.

[0085] In some preferred embodiments, based on thermo-hydraulic parameters, force equilibrium equations are constructed for aerosol particles in a Lagrangian system, including: obtaining the motion of aerosol particles in the flow field; constructing force equilibrium equations for aerosol particles; and calculating the force equilibrium equations as follows:

[0086]

[0087] in, F is the inertial force of aerosol particles. D (uu p ) is the drag force. F is the difference between gravity and buoyancy. a For the diffusing force of aerosol particles, u p Let ρ be the velocity of the aerosol particles, u be the gas velocity, and ρ be the velocity of the gas. p Let ρ be the density of the aerosol particles, and ρ be the gas density.

[0088] In some preferred embodiments, determining the modal region of the aerosol particles includes: determining the flow state of water vapor during the condensation process based on the particle flow equation; determining the modal region based on the flow state, wherein when the flow state is greater than a first preset value, the aerosol particles are in a free molecular state; when the flow state is equal to a second preset value, the aerosol particles are in a transition region; and when the flow state is less than the second preset value, the aerosol particles are in a slip region, wherein the first preset value is greater than or equal to the second preset value; wherein the particle flow equation is calculated as follows:

[0089]

[0090] Among them, K n For the flow state, λ is the mean free path of the mixture of the accident water vapor source term and air; d p The diameter of the aerosol particles is denoted as .

[0091] It should be noted that in actual conditions, the first preset value is much larger than the second preset value. When the flow state is greater than the first preset value, the aerosol particles are in a free molecular state. The aerosol particles in the free molecular state need to be removed by spraying droplets. Water vapor alone cannot completely remove them. Therefore, this state is not considered. Only the situation where the aerosol particles are in the slip zone and transition zone is considered.

[0092] In some preferred embodiments, when the modal region is a slip region, determining the diffusion force of aerosol particles within the modal region includes: the diffusion force of aerosol particles within the slip region is calculated as follows:

[0093]

[0094] Where: SD is the slip region, η is the viscosity of the mixed gas, R0 is the radius of the aerosol particles, and σ 12 The ratio of the diameter to the mass of the gas mixture. D represents the gradient of the molar composition of water vapor. 12 F is the diffusion coefficient. SD ∈F a .

[0095] It should be noted that in the slip zone, water vapor diffuses in the non-condensable gas, and this factor needs to be taken into account when calculating the diffusion force of aerosol particles.

[0096] Optional, σ 12 The ratio of the diameter to the mass of the gas mixture is determined as follows:

[0097]

[0098] Where d1 is the molecular diameter of water vapor, d 12 Let m1 be the average diameter of water vapor and non-condensable gas molecules, m2 be the molecular mass of water vapor, and m3 be the molecular mass of non-condensable gas.

[0099] In some preferred embodiments, when the modal region is a transition region, determining the diffusion force of aerosol particles within the modal region includes: the diffusion force of aerosol particles within the transition region is calculated as follows:

[0100]

[0101] Where D is the transition region, R is the radius of the aerosol particles, n is the number concentration of the gas mixture, m is the mass of the aerosol particles, k is the Boltzmann constant, T is the temperature inside the heat trap connected to the containment, and F... D ∈F a .

[0102] Step S110: Based on the diffusion migration motion, update the initial spatial position distribution of aerosol particles to obtain the target spatial position distribution of aerosol particles.

[0103] Optionally, based on diffusion migration, the orientation of aerosol particles can be obtained, thereby determining the target spatial distribution of aerosol particles in the next time step.

[0104] Step S112: Traverse the thermal-hydraulic parameters corresponding to multiple time steps, as well as the target spatial position distribution of aerosol particles corresponding to multiple time steps, to determine the motion results of unsteady radioactive aerosols in the containment computational domain.

[0105] Optionally, the motion of radioactive aerosol particles is a time-dependent motion. In the above method, the target spatial position distribution of aerosol particles in the first time step is obtained, and the target spatial position distribution of aerosol particles in each time step is obtained. According to the order of the time steps, the above target spatial position distribution is formed into a dynamic motion, which is the motion result of unsteady radioactive aerosols.

[0106] Through the above steps S102 to S112, the time, containment calculation domain, and aerosol particle interval are divided, and the multiple containment calculation domains and aerosol particle intervals within each time step are analyzed in detail. This achieves the technical effect of spatial fine division, making the assessment of aerosol vapor condensation removal rate under containment cooling conditions more accurate. In turn, it solves the technical problem that the assessment of aerosol vapor condensation removal rate under containment cooling conditions is incorrect due to insufficient spatial fineness.

[0107] Example 2

[0108] Based on the above embodiments and optional embodiments, the present invention also proposes an optional implementation method. Figure 5 This is a flowchart of an optional method for determining the diffusion migration of radioactive aerosols in Embodiment 2 of the present invention, as shown below. Figure 5 As shown, the method includes:

[0109] Step S1: Divide the containment computation domain of the accident object into several computation domain nodes, divide the physical time t during the accident process into different time steps (t0, t1...tn), and divide the aerosol particles into different particle size ranges.

[0110] Step S2: Iteratively solve the transport equation, component transport model and simplified mass and heat transfer model for the nodes of the containment computational domain at the current time step (first time step) to obtain the containment thermal-hydraulic parameters under condensation conditions at the current time step.

[0111] Step S3: Solve the force balance equation for each radioactive aerosol particle in the computational domain node at the current time step. The required physical parameters are obtained based on the computational domain node where the radioactive aerosol particle is located.

[0112] Step S4: Update the distribution of thermal-hydraulic parameters and the target spatial location distribution of radioactive aerosol particles in the containment computational domain nodes at the current time step.

[0113] Step S5: Update the current time step to the next time step, and start step S2 to continue iterative execution. If the physical time t has been reached, stop the calculation. At this time, the results of the unsteady radioactive aerosol motion on the containment computation domain have been obtained.

[0114] Through steps S1 to S5, the proposed model can be applied to assess the physical phenomenon of removing radioactive source terms during steam condensation caused by cooling in passive third-generation nuclear power plants. The simplified mass and heat transfer model can analyze the temporal evolution of containment thermal-hydraulic phenomena. Furthermore, the simplified model reduces two-phase flow to single-phase flow, thus improving computational efficiency. The proposed diffusion-phoresis force equilibrium model, by coupling the thermal-hydraulic calculation process, enables the study of the mechanism relating aerosol particle diffusion-phoresis behavior to the water vapor condensation state at the wall. The proposed refined calculation method allows for iterative calculations in both spatial and temporal dimensions within the containment computational domain, thereby enabling diffusion-phoresis analysis of uneven distributions of thermal-hydraulic parameters.

[0115] Example 3

[0116] This embodiment also provides a device for determining the motion of radioactive aerosol diffusion phoresis, which is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the terms "module" and "device" can refer to a combination of software and / or hardware that performs a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0117] According to an embodiment of the present invention, an apparatus embodiment for implementing the above-described method for determining the motion of radioactive aerosol diffusion is also provided. Figure 6 This is a schematic diagram of the structure of a radioactive aerosol diffusion migration determination device according to Embodiment 3 of the present invention, as shown below. Figure 6 As shown, the aforementioned radioactive aerosol diffusion migration motion determination device includes: an acquisition module 401, a division module 402, a thermo-hydraulic parameter determination module 403, a diffusion migration motion determination module 404, an update module 405, and a motion result module 406, wherein:

[0118] The acquisition module 401 is used to acquire the total duration from the start of the accident to the end of the accident, as well as the initial spatial distribution of aerosol particles inside the containment during the accident.

[0119] The partitioning module 402, connected to the acquisition module 401, is used to divide the total duration into multiple time steps, divide the computational domain of the containment into multiple computational domain nodes, and divide the aerosol particles into multiple particle size ranges.

[0120] The thermal-hydraulic parameter determination module 403 is connected to the partitioning module 402 and is used to select the first time step, perform iterative calculations on multiple computational domain nodes within the containment, and obtain the thermal-hydraulic parameters corresponding to the first time step. The first time step is the current time step among multiple time steps.

[0121] The diffusion migration motion determination module 404 is connected to the thermal hydraulic parameter determination module 403. It is used to perform force balance calculations on aerosol particles corresponding to multiple particle size ranges based on thermal hydraulic parameters, so as to obtain the diffusion migration motion of aerosol particles.

[0122] The update module 405 is connected to the diffusion migration motion determination module 404 and is used to update the initial spatial position distribution of aerosol particles based on diffusion migration motion to obtain the target spatial position distribution of aerosol particles.

[0123] The motion result module 406, connected to the update module 405, is used to traverse the thermal-hydraulic parameters corresponding to multiple time steps and the target spatial position distribution of aerosol particles corresponding to multiple time steps, and determine the motion result of unsteady radioactive aerosols in the containment computation domain.

[0124] It should be noted that the above modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following ways: the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0125] It should be noted that the acquisition module 401, the division module 402, the thermo-hydraulic parameter determination module 403, the diffusion migration motion determination module 404, the update module 405, and the motion result module 406 described above are implemented in the same instances and application scenarios as the corresponding steps, but are not limited to the content disclosed in the above embodiments. It should also be noted that the above modules, as part of the device, can run on a computer terminal.

[0126] It should be noted that the optional or preferred implementation methods of this embodiment can be found in the relevant descriptions in the embodiments, and will not be repeated here.

[0127] The aforementioned radioactive aerosol diffusion migration motion determination device may further include a processor and a memory. The aforementioned acquisition module 401, division module 402, thermo-hydraulic parameter determination module 403, diffusion migration motion determination module 404, update module 405, and motion result module 406 are all stored in the memory as program modules. The processor executes the aforementioned program modules stored in the memory to realize the corresponding functions.

[0128] The processor contains a core that retrieves the corresponding program modules from memory. One or more cores may be configured. Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory includes at least one memory chip.

[0129] According to an embodiment of this application, an embodiment of a non-volatile storage medium is also provided. Optionally, in this embodiment, the non-volatile storage medium includes a stored program, wherein, when the program is running, it controls the device containing the non-volatile storage medium to execute any of the aforementioned radioactive aerosol diffusion migration determination methods.

[0130] Optionally, in this embodiment, the non-volatile storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any mobile terminal in a group of mobile terminals, and the non-volatile storage medium includes stored programs.

[0131] Optionally, during program execution, the device containing the non-volatile storage medium may be controlled to perform the following functions: obtain the total duration from the start to the end of the accident, and the initial spatial distribution of aerosol particles within the containment during the accident; divide the total duration into multiple time steps, divide the computational domain of the containment into multiple computational domain nodes, and divide the aerosol particles into multiple particle size ranges; select the first time step, perform iterative calculations on the multiple computational domain nodes within the containment, and obtain the thermo-hydraulic parameters corresponding to the first time step, where the first time step is the current time step among multiple time steps; based on the thermo-hydraulic parameters, perform force balance calculations on the aerosol particles corresponding to the multiple particle size ranges respectively, and obtain the diffusion migration motion of the aerosol particles; based on the diffusion migration motion, update the initial spatial distribution of aerosol particles, and obtain the target spatial distribution of aerosol particles; traverse the thermo-hydraulic parameters corresponding to multiple time steps, and the target spatial distribution of aerosol particles corresponding to multiple time steps, and determine the motion result of unsteady radioactive aerosols in the computational domain of the containment.

[0132] According to an embodiment of this application, an embodiment of a processor is also provided. Optionally, in this embodiment, the processor is used to run a program, wherein the program executes any of the above-described methods for determining the motion of radioactive aerosol diffusion.

[0133] According to an embodiment of this application, an embodiment of a computer program product is also provided. Optionally, in this embodiment, the computer program product includes a computer program that, when executed by a processor, implements the steps of any of the above-described methods for determining the motion of radioactive aerosol diffusion.

[0134] Optionally, when the aforementioned computer program product is executed on a data processing device, it is suitable to execute an initialization program with the following method steps: obtaining the total duration from the start to the end of the accident, and the initial spatial distribution of aerosol particles within the containment during the accident; dividing the total duration into multiple time steps, dividing the computational domain of the containment into multiple computational domain nodes, and dividing the aerosol particles into multiple particle size intervals; selecting a first time step, iteratively calculating the multiple computational domain nodes within the containment to obtain the thermo-hydraulic parameters corresponding to the first time step, wherein the first time step is the current time step among the multiple time steps; based on the thermo-hydraulic parameters, performing force balance calculations on the aerosol particles corresponding to the multiple particle size intervals to obtain the diffusion migration motion of the aerosol particles; based on the diffusion migration motion, updating the initial spatial distribution of the aerosol particles to obtain the target spatial distribution of the aerosol particles; traversing the thermo-hydraulic parameters corresponding to the multiple time steps, and the target spatial distribution of the aerosol particles corresponding to the multiple time steps, to determine the motion result of the unsteady radioactive aerosols in the computational domain of the containment.

[0135] This invention provides an electronic device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs the following steps: obtaining the total duration from the start to the end of an accident, and the initial spatial distribution of aerosol particles within the containment during the accident; dividing the total duration into multiple time steps, dividing the computational domain of the containment into multiple computational domain nodes, and dividing the aerosol particles into multiple particle size ranges; selecting a first time step, iteratively calculating the multiple computational domain nodes within the containment to obtain the thermo-hydraulic parameters corresponding to the first time step, wherein the first time step is the current time step among the multiple time steps; based on the thermo-hydraulic parameters, performing force balance calculations on the aerosol particles corresponding to the multiple particle size ranges to obtain the diffusion migration motion of the aerosol particles; based on the diffusion migration motion, updating the initial spatial distribution of the aerosol particles to obtain the target spatial distribution of the aerosol particles; traversing the thermo-hydraulic parameters corresponding to multiple time steps and the target spatial distribution of the aerosol particles corresponding to multiple time steps to determine the motion result of the unsteady radioactive aerosols in the containment computational domain.

[0136] The order of the above embodiments of the present invention is merely for description and does not represent the superiority or inferiority of the embodiments.

[0137] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0138] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of modules described above can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between modules, and may be electrical or other forms.

[0139] The modules described above as separate components may or may not be physically separate. Similarly, the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple modules. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0140] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0141] If the aforementioned integrated modules are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable non-volatile storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a non-volatile storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned non-volatile storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0142] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the diffusion migration motion of radioactive aerosols, characterized in that, include: Obtain the total duration from the start to the end of the accident, as well as the initial spatial distribution of aerosol particles within the containment during the accident. The total duration is divided into multiple time steps, the computational domain of the containment is divided into multiple computational domain nodes, and the aerosol particles are divided into multiple particle size ranges. A first time step is selected, and iterative calculations are performed on the plurality of computational domain nodes within the containment to obtain the thermo-hydraulic parameters corresponding to the first time step, wherein the first time step is the current time step among the plurality of time steps; Based on the aforementioned thermal-hydraulic parameters, force balance calculations are performed on the aerosol particles corresponding to the multiple particle size ranges to obtain the diffusion migration motion of the aerosol particles. Based on the diffusion migration motion, the initial spatial position distribution of the aerosol particles is updated to obtain the target spatial position distribution of the aerosol particles; By iterating through the thermal-hydraulic parameters corresponding to the multiple time steps and the target spatial position distribution of the aerosol particles corresponding to the multiple time steps, the motion result of the unsteady radioactive aerosol in the containment computational domain is determined.

2. The method for determining the diffusion migration motion of radioactive aerosols according to claim 1, characterized in that, The step of selecting a first time step and iteratively calculating the multiple computational domain nodes within the containment to obtain the thermo-hydraulic parameters corresponding to the first time step includes: At multiple computational domain nodes, the airflow motion in the computational domain within the containment is solved based on the transport equations of the Euler system. Based on a component transport model of fluid mechanics, the mixing flow of accident water vapor source term with air is calculated, wherein the accident water vapor source term is used to indicate the quantity, temperature and pressure of water vapor released from the containment source under accident conditions; Based on the airflow motion and the mixed flow, a simplified mass and heat transfer model is obtained to obtain thermal-hydraulic parameters, wherein the mass and heat transfer model is used to indicate the condensation process of water vapor on the walls of the containment vessel.

3. The method for determining the diffusion migration motion of radioactive aerosols according to claim 2, characterized in that, Based on the airflow motion and the mixed flow, the simplified mass and heat transfer model is used to obtain thermal-hydraulic parameters, including: Determine the partial pressure of the water vapor within the containment. When the partial pressure of water vapor reaches the condensation critical point, the mass transfer flow rate is obtained based on the mass transfer and heat transfer model, wherein the mass transfer flow rate is used to indicate the amount of mass reduction of water vapor components caused by the condensation process of water vapor on the wall. Based on the mass and heat transfer model and the mass transfer flow rate, the heat transfer flow rate is obtained, wherein the heat transfer flow rate is used to indicate the amount of heat transferred during the condensation of water vapor on the wall surface. The thermal-hydraulic parameters are obtained by coupling the mass transfer flow rate and the heat transfer flow rate with the airflow motion and the mixed flow.

4. The method for determining the diffusion migration motion of radioactive aerosols according to claim 3, characterized in that, Determining the partial pressure of water vapor within the containment includes: The partial pressure of water vapor was determined based on the Clapeyron equation; The Clapeyron equation is calculated as follows: Where p is the partial pressure of water vapor, T is the temperature inside the heat trap device connected to the containment, and ΔH is... vap R is the latent heat of vaporization of water vapor, and R is the gas constant.

5. The method for determining the diffusion migration motion of radioactive aerosols according to claim 3, characterized in that, The process of obtaining mass transfer flow rate based on the mass and heat transfer model includes: The mass transfer flow rate is determined based on the condensation formula; The condensation formula is calculated as follows: Where, q m For mass transfer flow rate, W s ρ is the mass fraction of water vapor, D is the effective mass diffusion coefficient, v is the volume of water vapor, and n is the quantity concentration of the water vapor source term mixed with air in the accident.

6. The method for determining the diffusion migration motion of radioactive aerosols according to claim 3, characterized in that, The process of obtaining the heat transfer flow rate based on the mass transfer and heat transfer model and the mass transfer flow rate includes: The heat transfer flow rate is determined based on the condensation heat flow formula; The condensation heat flow formula is calculated as follows: H m =q m h s Among them, H m For heat transfer flow rate, q m For mass transfer flow rate, h s This represents the saturated vapor specific enthalpy at the corresponding pressure.

7. The method for determining the diffusion migration motion of radioactive aerosols according to claim 1, characterized in that, The step of performing force balance calculations on the aerosol particles corresponding to the multiple particle size ranges based on the thermohydraulic parameters to obtain the diffusion migration motion of the aerosol particles includes: Based on thermal-hydraulic parameters, force equilibrium equations for aerosol particles are constructed in a Lagrange system. Determine the modal region of the aerosol particles, wherein the modal region is used to indicate the motion state of the aerosol particles; Determine the diffusion force corresponding to the aerosol particles in the modal region, wherein the diffusion force is used to indicate the force by which the aerosol particles are swept toward the wall by the flow formed by water vapor from the condensation process; Based on the diffusion force, the diffusion motion of the aerosol particles is obtained.

8. The method for determining the diffusion migration motion of radioactive aerosols according to claim 7, characterized in that, The construction of force equilibrium equations for aerosol particles in a Lagrangian system based on thermo-hydraulic parameters includes: To obtain the motion of aerosol particles in the flow field; Construct force equilibrium equations for aerosol particles; The force equilibrium equation is calculated as follows: in, F is the inertial force of the aerosol particles. D (uu p ) is the drag force. F is the difference between gravity and buoyancy. a u is the diffusing force of the aerosol particles. p Let u be the velocity of the aerosol particles, and ρ be the gas velocity. p ρ is the density of the aerosol particles, and ρ is the gas density.

9. The method for determining the diffusion migration motion of radioactive aerosols according to claim 8, characterized in that, Determining the modal region of the aerosol particles includes: Based on the particle flow equation, the flow state of water vapor during the condensation process is determined; Based on the flow state, the modal region is determined, wherein when the flow state is greater than a first preset value, the aerosol particles are in a free molecular state; when the flow state is equal to a second preset value, the aerosol particles are in a transition region; and when the flow state is less than a second preset value, the aerosol particles are in a slip region, wherein the first preset value is greater than or equal to the second preset value. The particle flow equation is calculated as follows: Among them, K n The flow state is given by λ, where λ is the mean free path of the mixture of the accident water vapor source term and air; d p The diameter of the aerosol particles is denoted as .

10. The method for determining the diffusion migration motion of radioactive aerosols according to claim 9, characterized in that, When the modal region is a slip region, determining the diffusion force of the aerosol particles within the modal region includes: The diffusion force of the aerosol particles in the slip region is calculated as follows: Where: SD is the slip region, η is the viscosity of the mixed gas, R0 is the radius of the aerosol particles, and σ 12 The ratio of the diameter to the mass of the gas mixture. D represents the gradient of the molar composition of water vapor. 12 F is the diffusion coefficient. SD ∈F a .

11. The method for determining the diffusion migration motion of radioactive aerosols according to claim 9, characterized in that, When the modal region is a transition region, determining the diffusion force of the aerosol particles within the modal region includes: The diffusion force of the aerosol particles in the transition region is calculated as follows: Where D is the transition region, R is the radius of the aerosol particles, n is the number concentration of the gas mixture, m1 is the molecular mass of water vapor, m2 is the molecular mass of the non-condensable gas, k is the Boltzmann constant, and T is the temperature inside the heat trap device connected to the containment structure. D represents the gradient of the molar composition of water vapor. 12 F is the diffusion coefficient. D ∈F a .

12. A device for determining the diffusion migration motion of radioactive aerosols, characterized in that, include: The acquisition module is used to acquire the total duration from the start of the accident to the end of the accident, as well as the initial spatial distribution of aerosol particles inside the containment during the accident. The partitioning module is used to divide the total duration into multiple time steps, divide the computational domain of the containment into multiple computational domain nodes, and divide the aerosol particles into multiple particle size ranges. The thermal-hydraulic parameter determination module is used to select a first time step and perform iterative calculations on the plurality of computational domain nodes within the containment to obtain the thermal-hydraulic parameters corresponding to the first time step, wherein the first time step is the current time step among the plurality of time steps; The diffusion migration motion determination module is used to perform force balance calculations on the aerosol particles corresponding to the multiple particle size ranges based on the thermal-hydraulic parameters, so as to obtain the diffusion migration motion of the aerosol particles. The update module is used to update the initial spatial position distribution of the aerosol particles based on the diffusion migration motion, so as to obtain the target spatial position distribution of the aerosol particles. The motion results module is used to traverse the thermal-hydraulic parameters corresponding to the multiple time steps, as well as the target spatial position distribution of the aerosol particles corresponding to the multiple time steps, to determine the motion results of the unsteady radioactive aerosols in the containment computation domain.

13. A non-volatile storage medium, characterized in that, The non-volatile storage medium stores multiple instructions adapted for loading and execution by a processor of the method for determining the radioactive aerosol diffusion migration motion according to any one of claims 1 to 11.

14. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for determining the radioactive aerosol diffusion migration motion according to any one of claims 1 to 11.

Images