Method and device for determining aerosol retention efficiency of passive containment of nuclear power plant

Abstract

The application relates to a method and device for determining aerosol retention efficiency of a passive containment vessel of a nuclear power plant. The method comprises the following steps: determining a target condensation model corresponding to the passive containment vessel according to the structure type of the passive containment vessel; determining droplet radius distribution data of aerosol in a narrow gap of the passive containment vessel according to the initial droplet radius of the aerosol in the passive containment vessel, geometric size data of the narrow gap of the passive containment vessel and the target condensation model; determining gravity settling velocity distribution data corresponding to the narrow gap based on the droplet radius distribution data; and determining aerosol retention efficiency corresponding to the narrow gap based on the gravity settling velocity distribution data. The method can improve the accuracy of the calculation result of the aerosol retention efficiency.

Description

Technical Field

[0001] This application relates to the field of nuclear power technology, and in particular to a method and apparatus for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant. Background Technology

[0002] The passive containment vessel of a nuclear power plant is a crucial barrier for nuclear safety. Reducing the concentration of radioactive aerosols within the containment vessel during an accident is an effective means of preventing large-scale releases of radioactive materials. In the event of an accident, if the primary circuit boundary of the reactor is breached, radioactive aerosols can be carried by the primary coolant and released into the passive containment air. The pressure and temperature of the air within the passive containment will continuously rise, potentially causing a rupture and creating a narrow leak, ultimately leading to the release of radioactive materials. To mitigate the environmental impact of potential nuclear power plant accidents, it is necessary to assess the potential leakage of radioactive aerosols after an accident.

[0003] In the process of assessing radioactive aerosol leakage after a nuclear power plant accident, related technologies suggest that the narrow gaps in the containment can have a certain retention effect on aerosols in the carrier gas. However, the methods for calculating the containment aerosol retention efficiency in related technologies have low accuracy. Summary of the Invention

[0004] Therefore, it is necessary to provide a method and apparatus for determining the aerosol retention efficiency of a nuclear power plant's passive containment, which can improve the accuracy of aerosol retention efficiency calculation, in response to the above-mentioned technical problems.

[0005] In a first aspect, this application provides a method for determining the aerosol retention efficiency of the passive containment vessel in a nuclear power plant, including:

[0006] Based on the structural type of the passive containment, determine the target condensation model corresponding to the passive containment;

[0007] Based on the initial droplet radius of the aerosol inside the passive containment, the geometric dimensions of the narrow slit on the passive containment, and the target condensation model, the droplet radius distribution data corresponding to the aerosol in the narrow slit is determined.

[0008] Based on the droplet radius distribution data, determine the gravity settling velocity distribution data corresponding to the narrow slit;

[0009] Based on gravity settling velocity distribution data, the aerosol retention efficiency corresponding to the narrow slit is determined.

[0010] In one embodiment, the target condensation model corresponding to the passive containment is determined based on the structural type of the passive containment, including:

[0011] When the passive containment structure is a concrete structure, the target condensation model corresponding to the passive containment is determined to be a single-stage condensation model;

[0012] When the passive containment structure is a composite structure, the target condensation model corresponding to the passive containment is determined to be a two-stage condensation model. The composite structure includes concrete structure and metal structure.

[0013] When the passive containment structure is a metallic structure, the target condensation model corresponding to the passive containment is determined to be a gradual condensation model.

[0014] In one embodiment, based on the initial droplet radius of the aerosol within the passive containment, the geometric dimensions of the narrow slit on the passive containment, and the target condensation model, the droplet radius distribution data corresponding to the aerosol in the narrow slit is determined, including:

[0015] Based on the average carrier gas velocity, the initial gas temperature inside the containment, geometric data, and the target condensation model, convection-diffusion solutions are performed to obtain the temperature distribution data in the narrow slit.

[0016] Based on the average carrier gas velocity, initial vapor concentration inside the containment, geometric data, and target condensation model, convection-diffusion solution processing is performed to obtain vapor concentration distribution data in the narrow slit.

[0017] Based on temperature distribution data and vapor concentration distribution data, droplet radius distribution data are determined.

[0018] In one embodiment, convection-diffusion processing is performed based on the average carrier gas velocity, gas temperature inside the containment, geometric data, and the target condensation model to obtain temperature distribution data in the narrow slit, including:

[0019] When the geometry of the narrow slit is cylindrical, temperature distribution data is obtained by iterative calculation based on the average carrier gas velocity, initial gas temperature, geometric dimension data, target condensation model, and first temperature convection-diffusion function.

[0020] In one embodiment, convection-diffusion processing is performed based on the average carrier gas velocity, gas temperature inside the containment, geometric data, and the target condensation model to obtain temperature distribution data in the narrow slit, including:

[0021] When the geometry of the narrow slit is a parallel plate structure, temperature distribution data is obtained by iterative calculation based on the average carrier gas velocity, initial gas temperature, geometric dimension data, target condensation model, and second temperature convection-diffusion function.

[0022] In one embodiment, determining droplet radius distribution data based on temperature distribution data and vapor concentration distribution data includes:

[0023] Based on the temperature distribution data, determine the saturated vapor pressure distribution data in the narrow slit;

[0024] Based on the vapor concentration distribution data and saturated vapor pressure distribution data, the saturation ratio distribution data in the narrow slit is obtained;

[0025] Determine the activation diameter distribution data in the narrow slit based on the saturation ratio distribution data;

[0026] Based on the vapor concentration distribution data and temperature distribution data, the droplet radius growth rate distribution data of aerosols in the narrow slit was determined;

[0027] Based on the activation diameter distribution data, droplet radius growth rate distribution data, and initial droplet radius, the droplet radius distribution data is determined.

[0028] In one embodiment, determining the activation diameter distribution data in the slit based on saturation ratio distribution data includes:

[0029] Based on the correspondence between saturation ratio distribution data and Kelvin diameter, Kelvin diameter distribution data is obtained;

[0030] Based on the chemical properties of the aerosols, the Kelvin diameter distribution data were corrected to obtain the activated diameter distribution data.

[0031] In one embodiment, based on droplet radius distribution data, the gravity settling velocity distribution data corresponding to the narrow slit is determined, including:

[0032] Based on droplet radius distribution data, the droplet mixing density distribution data of aerosols in the narrow slit was determined;

[0033] Based on the droplet radius distribution data, droplet mixing density distribution data, and the correspondence between radius and velocity, the gravity settling velocity distribution data is obtained;

[0034] The radius-velocity correspondence includes the relationship between gravity settling velocity, droplet radius, and droplet mixing density.

[0035] In one embodiment, the geometric data includes the radial length of the slit;

[0036] Based on gravity settling velocity distribution data, the aerosol retention efficiency corresponding to the narrow slit was determined, including:

[0037] Based on gravity settling velocity distribution data, the target settling distance of aerosols in the narrow slit is determined.

[0038] The aerosol retention efficiency is determined based on the target settling distance and the radial length of the narrow slit.

[0039] Secondly, this application also provides a device for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant, comprising:

[0040] The model selection module is used to determine the target condensation model corresponding to the passive containment based on the structure type of the passive containment.

[0041] The radius calculation module is used to determine the droplet radius distribution data of the aerosol in the narrow slit based on the initial droplet radius of the aerosol inside the passive containment, the geometric dimensions of the narrow slit on the passive containment, and the target condensation model.

[0042] The velocity calculation module is used to determine the gravity settling velocity corresponding to the narrow slit based on droplet radius distribution data;

[0043] The efficiency calculation module is used to determine the aerosol retention efficiency corresponding to the narrow slit based on gravity settling velocity and geometric dimensions.

[0044] The aforementioned method and apparatus for determining the aerosol retention efficiency of the passive containment in nuclear power plants determine the target condensation model corresponding to the passive containment based on its structural type; determine the droplet radius distribution data corresponding to the aerosol in the narrow slit based on the initial droplet radius of the aerosol inside the passive containment, the geometric dimensions of the narrow slit on the passive containment, and the target condensation model; determine the gravity settling velocity distribution data corresponding to the narrow slit based on the droplet radius distribution data; and determine the aerosol retention efficiency corresponding to the narrow slit based on the gravity settling velocity distribution data. Thus, the above method takes into account the temperature difference between the high-temperature and high-humidity gases inside the containment vessel of a boiling water reactor or pressurized water reactor and the passive containment vessel wall after a nuclear power plant accident. It equates the narrow slit on the passive containment vessel to a condenser. By using the corresponding condensation model, initial droplet radius, and geometric dimensions of the narrow slit, it calculates the droplet radius distribution data corresponding to aerosols in the narrow slit. This data is used to measure the change in droplet radius as aerosols pass through the narrow slit, thereby determining the aerosol retention efficiency corresponding to the narrow slit. Compared to ignoring the condensation effect of the narrow slit on aerosol particles and using the initial droplet radius of the aerosol to calculate the gravity settling velocity when aerosols pass through the narrow slit, the above method considers the condensation effect of the narrow slit on aerosol particles and uses the droplet radius distribution data calculated based on the target condensation model to determine the gravity settling velocity. This makes the gravity settling effect calculated in this application more consistent with the actual retention effect of the narrow slit on aerosols, improving the accuracy of the aerosol retention efficiency calculation results. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is an application environment diagram of a method for determining the aerosol retention efficiency of a passive containment structure in a nuclear power plant, as shown in one embodiment.

[0047] Figure 2 This is a flowchart illustrating a method for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant, as shown in one embodiment.

[0048] Figure 3 This is a structural schematic diagram of a passive containment structure with a composite structure in one embodiment.

[0049] Figure 4 This is a schematic diagram illustrating the effect of a passive containment structure equivalent to a single-stage condensation model in one embodiment.

[0050] Figure 5 This is a schematic diagram illustrating the effect of a passive containment structure equivalent to a two-stage condensation model in one embodiment.

[0051] Figure 6 This is a schematic diagram illustrating the effect of a passive containment structure equivalent to a gradual condensation model in one embodiment.

[0052] Figure 7 This is a flowchart illustrating the steps for determining droplet radius distribution data in one embodiment;

[0053] Figure 8 This is a contour map of temperature distribution data in a narrow slit under a single-stage condensation model in one embodiment.

[0054] Figure 9 This is a contour map of temperature distribution data in a narrow slit under a two-stage condensation model in one embodiment.

[0055] Figure 10 This is a contour map of temperature distribution data in a narrow slit under a gradual condensation model in one embodiment.

[0056] Figure 11 This is a contour map of vapor concentration distribution data in a narrow slit under a single-stage condensation model in one embodiment.

[0057] Figure 12 This is a contour map of vapor concentration distribution data in a narrow slit under a two-stage condensation model in one embodiment.

[0058] Figure 13 This is a contour map of vapor concentration distribution data in a narrow slit under a gradual condensation model in one embodiment.

[0059] Figure 14 This is a contour map of Kelvin diameter distribution data in a narrow slit under a single-stage condensation model in one embodiment.

[0060] Figure 15 This is a contour map of the Kelvin diameter distribution data in a narrow slit under a two-stage condensation model in one embodiment.

[0061] Figure 16 This is a contour map of the Kelvin diameter distribution data in a narrow slit under a gradual condensation model in one embodiment.

[0062] Figure 17 This is a contour map of the droplet radius growth rate distribution data in a narrow slit under a single-stage condensation model in one embodiment.

[0063] Figure 18 This is a contour map of the droplet radius growth rate distribution data in a narrow slit under a two-stage condensation model in one embodiment.

[0064] Figure 19 This is a contour map of the droplet radius growth rate distribution data in a narrow slit under a gradual condensation model in one embodiment.

[0065] Figure 20 This is a schematic diagram of the aerosol retention area in one embodiment;

[0066] Figure 21 This is a structural block diagram of a device for determining the aerosol retention efficiency of a passive containment structure in a nuclear power plant, as shown in one embodiment.

[0067] Figure 22 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0069] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0070] The method for determining the aerosol retention efficiency of the passive containment vessel in a nuclear power plant provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be integrated onto server 104, or it can be located on a cloud or other network server. Terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, and tablets. Server 104 can be a standalone physical server, a server cluster or distributed system consisting of multiple physical servers, or a cloud server providing cloud computing services.

[0071] In one exemplary embodiment, such as Figure 2 As shown, a method for determining the aerosol retention efficiency of the passive containment in a nuclear power plant is provided, and this method is applied to... Figure 1 Taking terminal 102 as an example, it can be understood that this method can also be applied to a server, and to a system including both a terminal and a server, and is implemented through the interaction between the terminal and the server. The method includes steps 202 to 208. Wherein:

[0072] Step 202: Determine the target condensation model corresponding to the passive containment based on the structural type of the passive containment.

[0073] The applicant's research found that narrow slits in passive containment structures have a certain retention effect on aerosols. The retention mechanism of aerosols in narrow slits includes two mechanisms: the inlet effect and flow-through removal. Regarding the inlet effect, the higher the Stokes number of a particle, the easier it is to be retained; for example, all aerosol particles with a Stokes number greater than 1.5 are retained. This means that large-diameter aerosols (micrometer-sized) are easily removed, while nanoscale aerosols are difficult to remove through the inlet effect. Regarding flow-through retention, aerosols in laminar flow are mainly removed through gravity settling. Theoretically, this means that nanoscale aerosols are also difficult to remove along the flow path of the narrow slit, requiring the addition of an active retention system or the use of filters to retain aerosols. However, after extensive research, the applicant discovered that during an accident, the containment vessel of a pressurized water reactor or boiling water reactor is filled with a large amount of high-temperature and high-humidity gas. The temperature of the containment vessel itself is lower than the gas temperature, and the wall temperature of the leak slit is lower than the gas temperature. Therefore, the slit is equivalent to a condenser, which causes aerosol particles to be generated through condensation, resulting in larger aerosol particle diameters that are easier to remove through gravity settling.

[0074] Different containment structures are equivalent to different condensers. In one possible implementation, the passive containment structure types include concrete structures, composite structures, and metal structures. Specifically, when the passive containment structure is a concrete structure, the target condensation model is determined to be a single-stage condensation model; when the passive containment structure is a composite structure, the target condensation model is determined to be a two-stage condensation model, where the composite structure includes both concrete and metal structures; and when the passive containment structure is a metal structure, the target condensation model is determined to be a gradual condensation model.

[0075] For example, the thickness of the concrete containment shell is 1m; the composite structure containment shell includes an inner metal structure containment shell with a thickness of 6mm, and an outer concrete structure containment shell with a thickness of 1m, such as... Figure 3 As shown; the containment structure with a metal structure can be a steel containment structure; the containment structure using only a metal structure is made of steel, with a corresponding thickness of 4.5 cm. The thicknesses in the examples above are exemplary data; the thicknesses for various containment structure types are determined based on actual conditions, and the above data and their relationships are not intended to limit the thickness of the containment structure.

[0076] The boundary conditions differ for different condensation models. The passive containment structure of a concrete structure is equivalent to a single-stage condensation model, such as... Figure 4 As shown, the wall temperature is room temperature, i.e., the ambient temperature outside the passive containment; the inner layer of the composite structure is a metal structure, and the outer layer is a concrete structure, equivalent to a two-stage condensation model, as follows. Figure 5 As shown, for the steel section, the wall temperature changes gradually, heating to gas temperature at the slit inlet and cooling to room temperature at the slit outlet. For the concrete section, the slit wall temperature remains constant at room temperature. The passive containment structure of the metal structure is equivalent to a gradual condensation model, as shown below. Figure 6 As shown, the temperature of the narrow slit wall gradually changes, with the inlet heated to the gas level and the outlet cooled to room temperature.

[0077] This demonstrates that different types of passive containment structures have different equivalent condensers, resulting in varying condensation effects on aerosol particles and different degrees of particle radius increase, thus affecting the calculated retention efficiency. Therefore, in this embodiment, determining the corresponding target condensation model according to the structural type of the passive containment can improve the accuracy of the aerosol retention efficiency calculation results for the narrow slit.

[0078] In some implementations, the passive containment structure types include metal containment with passive external cooling systems, double-layer containment structures, and containment structures with insulation layers / coatings; different structure types can be equivalently represented by different condensation models to analyze the temperature changes of the narrow slit walls corresponding to different condensation models.

[0079] Step 204: Based on the initial droplet radius of the aerosol inside the passive containment, the geometric dimensions of the narrow slit on the passive containment, and the target condensation model, determine the droplet radius distribution data corresponding to the aerosol in the narrow slit.

[0080] The geometric dimensions of the slot on the passive containment include the radial length and axial length of the slot. For example, the axial length of the slot can also be referred to as the friction length of the slot, which is equal to the thickness of the passive containment. The radial length of the slot can be determined based on the volume of the passive containment and the speed of sound.

[0081] The initial droplet radius of the aerosols within the passive containment is used as input data. For example, in some application scenarios, data analysis shows that the geometric median diameter of the aerosol aggregate within the nuclear power plant containment during an accident is 0.44 μm with a standard deviation of 1.81. This means that 99% of the particles have a diameter greater than 74 nm, corresponding to a radius that is half the diameter.

[0082] The droplet radius distribution data refers to the radius of the droplet at various positions as the aerosol flows through the narrow slit, based on the initial droplet radius; due to condensation, the droplet radius at each position is generally different.

[0083] In one implementation, the slit is considered as a continuous radial (r)-axial (z) space, which is divided into multiple discrete nodes. The physical position of each discrete node is determined based on the geometric dimensions of the slit. The droplet radius distribution data includes the droplet radius value at the physical position of each discrete node.

[0084] Among them, the temperature distribution and vapor concentration distribution within the narrow slit can be analyzed based on the gas temperature and vapor concentration inside the containment and the corresponding condensation model, thereby determining the growth of the droplet radius and the droplet radius distribution.

[0085] In most cases, aerosol particles, after reaching a state of vapor supersaturation, will grow through condensation. Vapor supersaturation refers to a vapor concentration exceeding the vapor equilibrium concentration on a flat surface. This additional vapor quantity is needed to overcome the particle surface energy associated with particle curvature and surface tension. In laminar flow, the aerosol size increases by lowering the carrier gas temperature, which reduces the carrier gas equilibrium vapor pressure.

[0086] Step 206: Based on the droplet radius distribution data, determine the gravity settling velocity distribution data corresponding to the narrow slit.

[0087] Among them, based on the droplet radius distribution data, the gravity settling velocity of aerosols by the gravity settling mechanism of each discrete node in the narrow slit was determined.

[0088] Step 208: Based on the gravity settling velocity distribution data, determine the aerosol retention efficiency corresponding to the narrow slit.

[0089] The final settling distance of aerosol particles in the narrow slit can be calculated based on the gravity settling velocity and the axial length of the narrow slit. The aerosol retention efficiency can then be calculated based on this final settling distance and the radial length of the narrow slit.

[0090] The method for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant, provided in the above embodiments, determines the target condensation model corresponding to the passive containment vessel based on its structural type; determines the droplet radius distribution data corresponding to the aerosol in the narrow slit based on the initial droplet radius of the aerosol inside the passive containment vessel, the geometric dimensions of the narrow slit on the passive containment vessel, and the target condensation model; determines the gravity settling velocity distribution data corresponding to the narrow slit based on the droplet radius distribution data; and determines the aerosol retention efficiency corresponding to the narrow slit based on the gravity settling velocity distribution data. Thus, in this embodiment, considering the temperature difference between the high-temperature and high-humidity gases inside the containment vessel of a boiling water reactor or pressurized water reactor and the passive containment vessel wall after a nuclear power plant accident, the narrow slit on the passive containment vessel is equivalent to a condenser. Using the corresponding condensation model, initial droplet radius, and the geometric dimensions of the narrow slit, the droplet radius distribution data corresponding to the aerosol in the narrow slit is calculated. This data is used to measure the change in droplet radius as the aerosol passes through the narrow slit, thereby determining the aerosol retention efficiency corresponding to the narrow slit. Compared to ignoring the condensation effect of the narrow slit on aerosol particles and using the initial droplet radius to calculate the gravity settling velocity of the aerosol passing through the narrow slit, this embodiment considers the condensation effect of the narrow slit on aerosol particles and uses the droplet radius distribution data calculated based on the target condensation model to determine the gravity settling velocity. This makes the gravity settling effect calculated in this embodiment more consistent with the actual retention effect of the narrow slit on aerosols, improving the accuracy of the aerosol retention efficiency calculation results.

[0091] In one exemplary embodiment, based on Figure 2 The embodiment shown illustrates a method for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant. This method involves determining the droplet radius distribution data corresponding to the aerosol in the narrow slit based on the initial droplet radius of the aerosol within the passive containment, the geometric dimensions of the narrow slit in the passive containment, and the target condensation model. For example... Figure 7 As shown, the process includes steps 702 to 706.

[0092] Step 702: Based on the average carrier gas velocity, the initial gas temperature inside the containment, the geometric dimensions, and the target condensation model, perform convection-diffusion solution processing to obtain the temperature distribution data in the narrow slit.

[0093] The droplet growth process includes condensation heat release and vapor consumption related to droplet formation. Within the narrow slit, the wall temperature varies along the flow length according to different condensation models. In this embodiment, the temperature distribution and vapor concentration distribution within the narrow slit are determined by solving for steady-state convection-diffusion.

[0094] The steady-state convection-diffusion equation corresponding to temperature is shown in equation (1):

[0095] , formula (1)

[0096] in, ρ is the thermal diffusivity of air (unit: m² / s), and v is the velocity at various locations within the narrow slit. Represents the Laplace operator. This indicates divergence calculation.

[0097] In this embodiment, it is assumed that the velocity v is along the axial direction z of the narrow slit and has a fully developed parabolic manifold. The velocity v can be represented by the average flow velocity of the carrier gas in the narrow slit. Based on the average flow velocity of the carrier gas, the initial gas temperature in the containment, the geometric dimension data, and the wall temperature boundary conditions determined by the target condensation model and formula (1), the temperature distribution data in the narrow slit is obtained by iterative solution.

[0098] The carrier gas is a mixture of air, a large amount of high-temperature water vapor, and aerosols. In a passive containment leak accident, the aerosols are suspended in the carrier gas and move with the flow of the carrier gas.

[0099] The average carrier gas velocity refers to the average axial velocity of the carrier gas within the narrow slit. For example, the average carrier gas velocity can be calculated based on the pressure difference between the slit inlet and outlet.

[0100] In one possible implementation, when the geometry of the narrow slit is a cylindrical structure, formula (1) is transformed to obtain the first temperature convection diffusion function, as shown in formula (2); thus, temperature distribution data is obtained by iterative calculation based on the average flow rate of the carrier gas, the initial gas temperature, the geometric size data, the target condensation model and the first temperature convection diffusion function.

[0101] , formula (2)

[0102] In formula (2), U represents the average axial velocity of the carrier gas within the narrow slit (in m / s), i.e., the average velocity of the carrier gas. z represents the radial coordinate of the slit (in meters), and z is the axial coordinate of the slit (in meters). It is the radius of the cylindrical narrow slit (in meters). It is the partial derivative of temperature along the axial direction of the narrow slit (unit: K / m). It is the partial derivative of temperature along the radial direction of the narrow slit (unit: K / m). It is the thermal diffusivity of air (unit: m² / s).

[0103] In some application scenarios, formula (2) can be simplified and solved discretely. The specific solution is as follows: the continuous space of the narrow slit "radial r-axial z" is divided into discrete nodes (such as 10×20 nodes), each cell corresponds to a physical space point, and the temperature, concentration and other parameters of that point are stored; on the left side of formula (2), the axial temperature change rate is approximated by "forward difference", and the "temperature difference between the current axial node and the next node" is calculated according to formula (3):

[0104] , formula (3)

[0105] in, Let i be the temperature of the node with radial index i and axial index j. The axial step size is determined by the total slit length L and the number of axial nodes. Decide.

[0106] The first term on the right side of formula (2) approximates the radial temperature gradient using the "central difference" and considers the "1 / r" correction for the cylindrical coordinates. The "weighted temperature difference between the current radial node and the upper and lower nodes" is calculated according to formula (4):

[0107] , formula (4)

[0108] in, △r represents the radial step size. .

[0109] The first term on the right side of formula (2) is approximated by the axial second derivative using the "central difference". The "temperature difference between the current node and the preceding and following axial nodes" is calculated according to formula (5):

[0110] , formula (5)

[0111] Specifically, the slit wall temperature is determined based on the target condensation model. The slit wall temperature and the initial gas temperature are used as input boundaries to initiate iterative calculations, ensuring that the left side of the equations for all nodes equals the right side, thereby determining the temperature data for each node and obtaining the temperature distribution data in the slit.

[0112] For example, the applicant analyzed and calculated the temperature distribution data in the narrow slit using a carrier gas with an initial temperature of 80°C, a relative humidity of 100%, an average carrier gas flow rate of 10 m / s, and a humid narrow slit wall temperature of 25°C. Figure 8 , Figure 9 and Figure 10 As shown; the radial length of the narrow slot is 3 mm, and the axial length of the narrow slot varies depending on the structural type of the containment. The geometry of the narrow slot is a cylindrical structure. Figure 8This corresponds to the temperature distribution data within a narrow slit in a concrete structure, specifically under a single-stage condensation model. Figure 9 This corresponds to the temperature distribution data in the narrow slit under a composite structure, i.e., a two-stage condensation model. Figure 10 This corresponds to the temperature distribution data within the narrow slit of the metal structure, specifically under the gradual condensation model. Figures 8 to 10 In the diagram, the carrier gas flows from left to right. Both radial and axial coordinates are normalized. Because the flow is symmetrical, only the coordinates from the centerline are plotted. ) to the edge ( ( ) half-lateral curve.

[0113] In one possible implementation, when the geometry of the narrow slit is a parallel plate structure, the second temperature convection diffusion function is obtained by transforming formula (1), as shown in formula (6); thus, the temperature distribution data is obtained by iterative calculation based on the average flow rate of the carrier gas, the initial gas temperature, the geometric dimension data, the target condensation model, and the second temperature convection diffusion function.

[0114] , formula (6)

[0115] In formula (6), It is the radial coordinate (m) of the narrow slit in the parallel plate. It is half the spacing (m) of the narrow slit in the parallel plate, that is It is equal to half the radial length of the narrow slit. On the left side of formula (6), the approximate axial temperature change rate is calculated using formula (7) with a "forward difference":

[0116] , formula (7)

[0117] On the right side of formula (6), calculate the approximate second-order partial derivative of the "central difference" according to formulas (8) and (9):

[0118] , formula (8)

[0119] , formula (9)

[0120] Specifically, the slit wall temperature is determined based on the target condensation model. The slit wall temperature and the initial gas temperature are used as input boundaries to initiate iterative calculations, ensuring that the left side of the equations for all nodes equals the right side, thereby determining the temperature data for each node and obtaining the temperature distribution data in the slit.

[0121] Step 704: Based on the average carrier gas velocity, the initial vapor concentration inside the containment, the geometric data, and the target condensation model, perform convection-diffusion solution processing to obtain the vapor concentration distribution data in the narrow slit.

[0122] For example, the steady-state convection-diffusion equation corresponding to the vapor concentration is shown in equation (10):

[0123] , formula (10)

[0124] Where D is the molecular diffusivity of water vapor in air (unit: m² / s), and v is the velocity at various positions within the narrow slit. Represents the Laplace operator. This indicates divergence calculation.

[0125] In this embodiment, it is assumed that the velocity v is along the axial direction z of the narrow slit and has a fully developed parabolic manifold. The velocity v can be represented by the average flow velocity of the carrier gas in the narrow slit. Based on the average flow velocity of the carrier gas, the initial vapor temperature in the containment, the geometric data, and the wall vapor concentration boundary conditions determined by the target condensation model and formula (10), the vapor concentration distribution data in the narrow slit is obtained by iterative solution.

[0126] The gas state at the wall is determined by the wall temperature and reaches local thermodynamic equilibrium, as shown in equations (11) and (12).

[0127] , formula (11)

[0128] , formula (12)

[0129] in, This indicates the temperature distribution on the wall surface (e.g., from cold to hot transition, determined according to the condensation model). Indicates corresponding to Water vapor concentration at dew point (100% relative humidity).

[0130] The process of calculating vapor concentration distribution data is similar to that of calculating temperature concentration distribution data. In one possible implementation, when the geometry of the slit is cylindrical, formula (10) is transformed to obtain the first vapor concentration convection diffusion function, which is similar in form to formula (2). The thermal diffusivity in formula (2) is then used. Replace with molecular diffusivity ,temperature Replace with concentration The specific formula will not be elaborated here; thus, based on the average carrier gas velocity, initial vapor concentration, geometric size data, target condensation model, and first vapor concentration convection diffusion function, iterative calculations are performed to obtain vapor concentration distribution data. In one possible implementation, when the geometry of the narrow slit is a parallel plate structure, formula (10) is transformed to obtain the second vapor concentration convection diffusion function, which is similar in form to formula (6), and the thermal diffusivity in formula (6) is... Replace with molecular diffusivity ,temperature Replace with concentration The specific formula will not be elaborated here; thus, based on the average carrier gas velocity, initial vapor concentration, geometric size data, target condensation model, and second vapor concentration convection diffusion function, iterative calculations are performed to obtain vapor concentration distribution data.

[0131] For example, the applicant analyzed and calculated the vapor concentration distribution data in the narrow slit using a carrier gas with an initial temperature of 80°C, a relative humidity of 100%, an average carrier gas flow rate of 10 m / s, and a humid narrow slit wall temperature of 25°C. Figure 11 , Figure 12 and Figure 13 As shown; the radial length of the narrow slot is 3 mm, and the axial length of the narrow slot varies depending on the structural type of the containment. The geometry of the narrow slot is a cylindrical structure. Figure 11 For concrete structures, this refers to the vapor concentration distribution data in narrow gaps under a single-stage condensation model. Figure 12 This corresponds to the vapor concentration distribution data in the narrow slit under a complex structure, i.e., a two-stage condensation model. Figure 13 This corresponds to the vapor concentration distribution data in the narrow slit under the gradual condensation model, specifically for a metallic structure. Figures 11 to 13 In the diagram, the carrier gas flows from left to right. Both radial and axial coordinates are normalized. Because the flow is symmetrical, only the coordinates from the centerline are plotted. ) to the edge ( ( ) half-lateral curve.

[0132] Step 706: Determine the droplet radius distribution data based on the temperature distribution data and vapor concentration distribution data.

[0133] In this system, the temperature of each discrete node within the narrow slit determines the water vapor capacity of each node; the higher the temperature, the more water vapor it can hold. The vapor concentration of each discrete node represents its actual loading capacity. Based on these two data points, the saturation ratio of each discrete node can be determined, thereby determining the diameter of aerosol particles that can condense and grow within each discrete node. Simultaneously, the vapor concentration at each discrete point characterizes how many water molecules can collide with the droplets, and the temperature at each discrete point determines whether the latent heat released by water vapor condensation is dissipated. Therefore, based on the vapor concentration and temperature, the radius growth rate corresponding to each discrete point can be calculated, thereby determining the radius data corresponding to each discrete node.

[0134] In one possible implementation, the process of determining droplet radius distribution data based on temperature distribution data and vapor concentration distribution data includes steps A2 to A10.

[0135] Step A2: Determine the saturated vapor pressure distribution data in the narrow slit based on the temperature distribution data.

[0136] The higher the temperature, the more water vapor the air can hold. Therefore, the saturated vapor pressure distribution at various locations within the narrow slit can be determined based on the temperature distribution data.

[0137] For example, for each local location in the narrow slit (i.e., the aforementioned discrete nodes), the saturated vapor pressure corresponding to that local location is determined according to the temperature at that local location, using empirical thermodynamic formulas such as the Antoine equation or the Wagner equation; thus obtaining the saturated vapor pressure distribution data in the narrow slit.

[0138] Step A4: Based on the vapor concentration distribution data and saturated vapor pressure distribution data, obtain the saturation ratio distribution data in the narrow slit.

[0139] In this context, the saturation ratio at each local location within the narrow slit is equal to the ratio of vapor concentration to saturated vapor pressure.

[0140] Step A6: Determine the activation diameter distribution data in the narrow slit based on the saturation ratio distribution data.

[0141] One important parameter for aerosol particle size condensation growth is the Kelvin equivalent diameter. The calculation process is shown in formula (13):

[0142] , formula (13)

[0143] In formula (13), , and These are the molecular weight of water, liquid density, and surface tension, respectively. It is the universal gas constant. It is absolute temperature. It's the saturation ratio. Kelvin equivalent diameter. Corresponding to the equilibrium vapor pressure by the saturation ratio The diameter of the water droplet is determined.

[0144] In one possible implementation / exemplary method, the Kelvin equivalent diameter corresponding to each discrete node is calculated according to formula (13), and the Kelvin equivalent diameter is used as the activation diameter to determine the activation diameter corresponding to each discrete node, thereby obtaining the activation diameter distribution data in the slit.

[0145] For example, based on the chemical properties of the aerosol, the Kelvin diameter is corrected to better match the chemical properties of the particles, thus improving the accuracy of the activation diameter. In this example, the process of determining the activation diameter distribution data in the narrow slit based on the saturation ratio distribution data includes: obtaining the Kelvin diameter distribution data based on the correspondence between the saturation ratio distribution data and the Kelvin diameter; correcting the Kelvin diameter distribution data according to the chemical properties of the aerosol to obtain the activation diameter distribution data. The correspondence between the Kelvin diameter and the saturation ratio includes the relationship between the saturation ratio and the Kelvin diameter, as shown in formula (13). For each discrete node, the Kelvin diameter corresponding to the discrete node is calculated according to formula (13) and the saturation ratio corresponding to the discrete node. Then, the Kelvin diameter is corrected according to the chemical properties of the aerosol to obtain the activation diameter corresponding to the discrete node, thereby obtaining the activation diameter distribution data in the narrow slit.

[0146] In this case, if the chemical properties of the aerosol indicate that it is a hydrophobic particle, the Kelvin diameter is increased to obtain the activation diameter. If the chemical properties indicate that the aerosol is a soluble particle, the Kelvin diameter is decreased to obtain the activation diameter. This is because the dissolution of soluble particles lowers the equilibrium vapor pressure, resulting in a smaller critical diameter for their growth, making the activation diameter obtained by decreasing the Kelvin diameter more accurate. When the chemical properties of the aerosol do not meet either of these conditions, the Kelvin diameter is directly determined as the activation diameter.

[0147] Step A8: Based on the vapor concentration distribution data and temperature distribution data, determine the droplet radius growth rate distribution data of the aerosol in the narrow slit.

[0148] After determining the vapor concentration and temperature distribution data within the narrow slit, droplet growth was evaluated by numerically integrating the growth rate along the particle trajectory. Although droplet size and environment vary with flow, the time it takes for the droplet to reach equilibrium with its surroundings is much shorter than the time it takes to pass through the condenser. Therefore, it is assumed that the droplet characteristics exist independently in an infinite volume under steady state for approximate calculations.

[0149] Under the steady-state assumption, the droplet radius The calculation process for the rate of change is shown in formula (14):

[0150] , formula (14)

[0151] In formula (14), It is the radius growth rate of aerosol droplets (unit: m / s). It is the molecular diffusivity of water vapor in the air (unit: m² / s). It is the density of liquid water (unit: kg / m³). It is the vapor concentration (unit: kg / m³) corresponding to the node with radial index i and axial index j within the narrow slit. It is the water vapor saturation concentration on the surface of aerosol droplets (unit: kg / m³). It is the current radius of the aerosol droplet (unit: m). It is the Knudsen number correction factor (dimensionless, used to correct the discontinuous medium effect of molecular diffusion).

[0152] in, The calculation process is shown in formula (15):

[0153] , formula (15)

[0154] In formula (15), It is the level liquid surface at the node temperature The saturated vapor pressure of water vapor at this temperature (unit: Pa). It is the universal gas constant (unit: J / (mol·K)). It is the air temperature of the corresponding node within the narrow slit (unit: K, i.e., the temperature corresponding to that node in the temperature distribution data). It is the surface tension of the droplet surface (unit: N / m). It is the molar mass of water (unit: kg / mol). It is the density of liquid water (unit: kg / m³). It is the current radius of the aerosol droplet (unit: m).

[0155] This is a correction term used to determine whether aerosol particles are in a free molecule or continuous medium region and to make corrections (particles with Kn less than 1 are considered continuous medium). Approximately equal to 1; particles with Kn greater than 1 are considered free molecules. (The coefficients are less than 1), and the correction term is calculated using the Foghs-Sutukin correction method:

[0156] , formula (16)

[0157] Among them, Knudsen number , It is the molecular mean free path ( , It is the average molecular velocity, and D is the molecular diffusivity of water vapor in the air (approximately 2.5 × 10⁻⁶ at room temperature). -5 m² / s).

[0158] Step A10: Determine the droplet radius distribution data based on the activation diameter distribution data, droplet radius growth rate distribution data, and initial droplet radius.

[0159] Among them, the activation diameter distribution data is used to determine where aerosol particles begin to grow, and the droplet radius growth rate distribution data is used to determine the growth rate of aerosol particles. Combined with the initial droplet radius, the droplet radius corresponding to each position of the aerosol in the narrow slit can be determined.

[0160] In the above embodiments, the saturated vapor pressure distribution data in the narrow slit is determined based on the temperature distribution data; the saturation ratio distribution data in the narrow slit is obtained based on the vapor concentration distribution data and the saturated vapor pressure distribution data; the activated diameter distribution data in the narrow slit is determined based on the saturation ratio distribution data; the droplet radius growth rate distribution data of the aerosol in the narrow slit is determined based on the vapor concentration distribution data and the temperature distribution data; and the droplet radius distribution data is determined based on the activated diameter distribution data, the droplet radius growth rate distribution data, and the initial droplet radius. Thus, by calculating the distribution of the activated diameter and the droplet radius growth rate distribution data, a spatially refined model of the hygroscopic growth process of aerosol particles in the narrow slit is achieved, improving the accuracy of the droplet radius distribution data determination.

[0161] For example, the applicant analyzed and calculated the Kelvin diameter distribution data in the narrow slit using a carrier gas with an initial temperature of 80°C, a relative humidity of 100%, an average carrier gas velocity of 10 m / s, and a humid narrow slit wall temperature of 25°C. The obtained data are as follows: Figure 14 , Figure 15 and Figure 16 As shown, the distribution data of the droplet radius growth rate in the narrow slit are obtained as follows: Figure 17 , Figure 18 and Figure 19 As shown; the radial length of the narrow slot is 3 mm, and the axial length of the narrow slot varies depending on the structural type of the containment. The geometry of the narrow slot is a cylindrical structure. Figure 14 and Figure 17 For concrete structures, these are the Kelvin diameter distribution data and droplet radius growth rate distribution data in a narrow slit under a single-stage condensation model. Figure 15 and Figure 18 This corresponds to a composite structure, specifically the Kelvin diameter distribution data and droplet radius growth rate distribution data within the narrow slit under a two-stage condensation model. Figure 16 and Figure 19 The corresponding data are for the metal structure, namely the Kelvin diameter distribution data and the droplet radius growth rate distribution data in the narrow slit under the gradual condensation model.

[0162] The calculation results show that the maximum Kelvin diameter of the particles in the narrow slit is about 30 nm. It is generally believed that the geometric median diameter of aerosols in the containment vessel of a nuclear power plant under accident conditions is 0.44 μm with a standard deviation of 1.81. This means that 99% of the particles have a diameter greater than 74 nm, which means that 99% of the particles are larger than the minimum diameter for aerosol condensation in the narrow slit. These particles can all absorb moisture and grow in the narrow slit (both hydrophilic and hydrophobic aerosols can do so).

[0163] In an exemplary embodiment, during the process of determining droplet distribution data based on temperature distribution data and vapor concentration distribution data, the activation diameter distribution data may not be calculated; instead, the droplet radius distribution data can be determined by assuming that all droplets will condense and grow after entering the narrow slit. In this embodiment, the process of determining droplet radius distribution data based on temperature distribution data and vapor concentration distribution data includes steps B2 and B4.

[0164] Step B2: Based on the vapor concentration distribution data and temperature distribution data, determine the droplet radius growth rate distribution data of the aerosol in the narrow slit.

[0165] Step B4: Determine the droplet radius distribution data based on the droplet radius growth rate distribution data and the initial droplet radius.

[0166] In one exemplary embodiment, based on Figure 2 The embodiment shown describes the process of determining the gravity settling velocity distribution data corresponding to a narrow slit based on droplet radius distribution data. This process includes steps C2 to C4.

[0167] Step C2: Based on the droplet radius distribution data, determine the droplet mixing density distribution data of the aerosol in the narrow slit.

[0168] The droplet mixing density of aerosols refers to the total density of aerosol particles after the radius of the aerosol particles increases. For example, assuming the droplet has a core-shell structure of "dry particle core + water film", the calculation process of the droplet mixing density of aerosols is shown in formula (17):

[0169] , formula (17)

[0170] In formula (17), This represents the droplet mixing density of aerosol particles after particle size increase (unit: kg / m³). Indicates the density of the initial dry particles (e.g.) aerosols kg / m³); Indicates the initial volume of dry particles ( , (where the initial droplet radius is...) The density of liquid water ( kg / m³), This represents the volume of liquid water encapsulating the dry particles ( , (The radius of the grown droplet).

[0171] Step C4: Based on the droplet radius distribution data, droplet mixing density distribution data, and the radius-velocity correspondence, obtain the gravity settling velocity distribution data; wherein, the radius-velocity correspondence includes the correspondence between gravity settling velocity, droplet radius, and droplet mixing density.

[0172] In the case where the flow state along the narrow slit is laminar, the retention mode of aerosols in the laminar flow is mainly gravity settling. The gravity settling velocity is related to the droplet radius and the droplet mixing density. For example, based on Stokes' law, the radius velocity correspondence in this embodiment is shown in formula (18). Based on formula (18), it can be seen that the larger the droplet radius of the aerosol, the faster the settling velocity and the better the retention effect of the narrow slit.

[0173] , formula (18)

[0174] In formula (18), This indicates the gravitational settling velocity of aerosol particles (unit: m / s). This represents the acceleration due to gravity (unit: m / s², taken as 9.81 m / s²). This indicates the diameter of the aerosol particles after the particle size increase (unit: m). This represents the total density of aerosol particles after particle size increase (unit: kg / m³, i.e., droplet mixing density). This indicates the density of air (unit: kg / m³, approximately 1.2 kg / m³ at room temperature). It represents the dynamic viscosity of air (unit: Pa·s).

[0175] In one exemplary embodiment, based on Figure 2 In the illustrated embodiment, the geometric dimensions include the slit orientation length and the slit radial length. This embodiment relates to a process for determining the aerosol retention efficiency corresponding to the slit based on gravity settling velocity distribution data and geometric dimensions; this process includes steps D2 and D4.

[0176] Step D2: Determine the target settling distance of aerosols in the narrow slit based on the gravity settling velocity.

[0177] Among them, the target settling distance determines the final settling distance of an aerosol when passing through a narrow gap.

[0178] In one possible implementation, the residence time of the aerosol at each discrete node is determined based on the average velocity of the carrier gas and the axial length of the slit. For example, the time taken to reach the next discrete node B along the axial direction from one discrete node A is used as the residence time corresponding to discrete node A. Based on the residence time of the aerosol at each discrete node and the gravity settling velocity corresponding to each discrete node, the target settling distance of the aerosol in the slit is calculated point by point to finally obtain the target settling distance of the aerosol in the slit.

[0179] In one possible implementation, the flow data of aerosols along the narrow slit is first determined, wherein the flow velocity along the slit includes the axial flow velocity corresponding to each discrete node; based on the flow data along the slit and the distance between each discrete node, the residence time corresponding to each discrete node is determined, and then the target settlement distance is calculated.

[0180] Step D4: Determine the aerosol retention efficiency based on the target settling distance and the radial length of the narrow slit.

[0181] Since the direction of gravitational settling is downward, aerosols in zone 1 will be trapped at the narrow slit entrance, such as... Figure 20 As shown, the green area A1 represents the aerosols that will eventually be trapped within this range, and A represents the entire slit interface. In this example, the first trapping efficiency is the ratio of the cross-sectional area of ​​the trapping area to the cross-sectional area of ​​the entire slit, and the specific calculation process is shown in formula (19):

[0182] , formula (19)

[0183] In formula (19), D represents the slit diameter.

[0184] In one exemplary embodiment, such as Figure 2 As shown, a method for determining the aerosol retention efficiency of the passive containment in a nuclear power plant is provided, and this method is applied to... Figure 1 Taking terminal 102 as an example, it can be understood that this method can also be applied to a server, and also to a system that includes both a terminal and a server, and is implemented through the interaction between the terminal and the server. The method includes the following steps S2 to S12.

[0185] Step S2: Determine the target condensation model corresponding to the passive containment based on the structural type of the passive containment.

[0186] Optionally, when the passive containment structure is a concrete structure, the target condensation model corresponding to the passive containment is determined to be a single-stage condensation model; when the passive containment structure is a composite structure, the target condensation model corresponding to the passive containment is determined to be a two-stage condensation model, where the composite structure includes both concrete and metal structures; and when the passive containment structure is a metal structure, the target condensation model corresponding to the passive containment is determined to be a gradual condensation model.

[0187] Step S4: Based on the average carrier gas velocity, the initial gas temperature inside the containment, the geometric dimensions, and the target condensation model, perform convection-diffusion solution processing to obtain the temperature distribution data in the narrow slit.

[0188] Optionally, when the geometry of the narrow slit is cylindrical, temperature distribution data is obtained by iterative calculation based on the average carrier gas velocity, initial gas temperature, geometric dimension data, target condensation model, and first temperature convection-diffusion function.

[0189] When the geometry of the narrow slit is a parallel plate structure, temperature distribution data is obtained by iterative calculation based on the average carrier gas velocity, initial gas temperature, geometric dimension data, target condensation model, and second temperature convection-diffusion function.

[0190] Step S6: Based on the average carrier gas velocity, the initial vapor concentration inside the containment, the geometric data, and the target condensation model, perform convection-diffusion solution processing to obtain the vapor concentration distribution data in the narrow slit;

[0191] Step S8: Determine the droplet radius distribution data based on the temperature distribution data and vapor concentration distribution data.

[0192] Optionally, droplet radius distribution data is determined based on temperature distribution data and vapor concentration distribution data, including: determining saturated vapor pressure distribution data in the narrow slit based on temperature distribution data; obtaining saturation ratio distribution data in the narrow slit based on vapor concentration distribution data and saturated vapor pressure distribution data; determining activated diameter distribution data in the narrow slit based on saturation ratio distribution data; determining droplet radius growth rate distribution data of aerosol in the narrow slit based on vapor concentration distribution data and temperature distribution data; and determining droplet radius distribution data based on activated diameter distribution data, droplet radius growth rate distribution data, and initial droplet radius.

[0193] Optionally, the activation diameter distribution data in the narrow slit is determined based on the saturation ratio distribution data, including: obtaining the Kelvin diameter distribution data based on the correspondence between the saturation ratio distribution data and the Kelvin diameter; and correcting the Kelvin diameter distribution data according to the chemical properties of the aerosol to obtain the activation diameter distribution data.

[0194] Step S10: Based on the droplet radius distribution data, determine the gravity settling velocity distribution data corresponding to the narrow slit;

[0195] Optionally, based on the droplet radius distribution data, the gravity settling velocity distribution data corresponding to the narrow slit is determined, including: based on the droplet radius distribution data, determining the droplet mixing density distribution data of the aerosol in the narrow slit; and based on the droplet radius distribution data, the droplet mixing density distribution data, and the radius-velocity correspondence, obtaining the gravity settling velocity distribution data; wherein, the radius-velocity correspondence includes the correspondence between gravity settling velocity, droplet radius, and droplet mixing density.

[0196] Step S12: Based on the gravity settling velocity distribution data, determine the aerosol retention efficiency corresponding to the narrow slit.

[0197] Optionally, determining the aerosol retention efficiency corresponding to the narrow slit based on gravity settling velocity distribution data includes: determining the target settling distance of aerosols in the narrow slit based on gravity settling velocity distribution data; and determining the aerosol retention efficiency based on the target settling distance and the radial length of the narrow slit.

[0198] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0199] It is understood that the term "based on" as used in this application is used to describe one or more factors that influence the determination, but does not exclude other factors that may influence the determination. For example, the phrase "determine A based on B" means that the determination of A can be based entirely or at least partially on factor B. That is, B is a factor that influences the determination of A, but does not exclude the fact that the determination of A is also based on C.

[0200] Based on the same inventive concept, this application also provides a device for determining the aerosol retention efficiency of a nuclear power plant's passive containment structure, used to implement the aforementioned method for determining the aerosol retention efficiency of a nuclear power plant's passive containment structure. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the device for determining the aerosol retention efficiency of a nuclear power plant's passive containment structure provided below can be found in the limitations of the method for determining the aerosol retention efficiency of a nuclear power plant's passive containment structure described above, and will not be repeated here.

[0201] In one exemplary embodiment, such as Figure 21 As shown, a device for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant is provided, comprising: a model selection module 2102, a radius calculation module 2104, a velocity calculation module 2106, and an efficiency calculation module 2108, wherein:

[0202] The model selection module 2102 is used to determine the target condensation model corresponding to the passive containment based on the structural type of the passive containment.

[0203] The radius calculation module 2104 is used to determine the droplet radius distribution data of the aerosol in the narrow slit based on the initial droplet radius of the aerosol inside the passive containment, the geometric dimension data of the narrow slit on the passive containment, and the target condensation model.

[0204] The velocity calculation module 2106 is used to determine the gravity settling velocity corresponding to the narrow slit based on the droplet radius distribution data.

[0205] The efficiency calculation module 2108 is used to determine the aerosol retention efficiency corresponding to the narrow slit based on gravity settling velocity and geometric dimension data.

[0206] In an exemplary embodiment, the model selection module 2102 is used to determine the target condensation model corresponding to the passive containment as a single-stage condensation model when the structure type of the passive containment is a concrete structure; to determine the target condensation model corresponding to the passive containment as a two-stage condensation model when the structure type of the passive containment is a composite structure, wherein the composite structure includes a concrete structure and a metal structure; and to determine the target condensation model corresponding to the passive containment as a gradual condensation model when the structure type of the passive containment is a metal structure.

[0207] In an exemplary embodiment, the radius calculation module 2104 is used to perform convection-diffusion solution processing based on the average carrier gas flow rate, the initial gas temperature inside the containment, geometric size data, and the target condensation model to obtain temperature distribution data in the narrow slit; perform convection-diffusion solution processing based on the average carrier gas flow rate, the initial vapor concentration inside the containment, geometric size data, and the target condensation model to obtain vapor concentration distribution data in the narrow slit; and determine droplet radius distribution data based on the temperature distribution data and the vapor concentration distribution data.

[0208] In an exemplary embodiment, the radius calculation module 2104 is used to perform iterative calculations based on the average carrier gas velocity, initial gas temperature, geometric dimension data, target condensation model, and first temperature convection-diffusion function when the geometry of the narrow slit is a cylindrical structure, to obtain temperature distribution data.

[0209] In an exemplary embodiment, the radius calculation module 2104 is used to perform iterative calculations based on the average carrier gas velocity, initial gas temperature, geometric dimension data, target condensation model, and second temperature convection-diffusion function when the geometry of the narrow slit is a parallel plate structure, to obtain temperature distribution data.

[0210] In an exemplary embodiment, the radius calculation module 2104 is used to determine the saturated vapor pressure distribution data in the narrow slit based on the temperature distribution data; obtain the saturation ratio distribution data in the narrow slit based on the vapor concentration distribution data and the saturated vapor pressure distribution data; determine the activated diameter distribution data in the narrow slit based on the saturation ratio distribution data; determine the droplet radius growth rate distribution data of the aerosol in the narrow slit based on the vapor concentration distribution data and the temperature distribution data; and determine the droplet radius distribution data based on the activated diameter distribution data, the droplet radius growth rate distribution data, and the initial droplet radius.

[0211] In an exemplary embodiment, the radius calculation module 2104 is used to obtain Kelvin diameter distribution data based on the correspondence between saturation ratio distribution data and Kelvin diameter; and to correct the Kelvin diameter distribution data according to the chemical properties of the aerosol to obtain activated diameter distribution data.

[0212] In an exemplary embodiment, the velocity calculation module 2106 is used to determine the droplet mixing density distribution data of the aerosol in the narrow slit based on the droplet radius distribution data; and to obtain the gravity settling velocity distribution data based on the droplet radius distribution data, the droplet mixing density distribution data, and the radius velocity correspondence; wherein, the radius velocity correspondence includes the correspondence between the gravity settling velocity, the droplet radius, and the droplet mixing density.

[0213] In an exemplary embodiment, the geometric data includes the radial length of the slit; the efficiency calculation module 2108 is used to determine the target settling distance of aerosols in the slit based on the gravity settling velocity distribution data; and to determine the aerosol retention efficiency based on the target settling distance and the radial length of the slit.

[0214] The modules in the aforementioned device for determining the aerosol retention efficiency of the passive containment vessel in a nuclear power plant can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0215] In one exemplary embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 22 As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, Near Field Communication (NFC), or other technologies. When executed by the processor, the computer program implements a method for determining the aerosol retention efficiency of the passive containment vessel in a nuclear power plant. The display unit is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0216] Those skilled in the art will understand that Figure 22 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0217] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0218] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0219] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0220] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0221] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0222] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0223] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant, characterized in that, The method includes: Based on the structural type of the passive containment, determine the target condensation model corresponding to the passive containment; Based on the initial droplet radius of the aerosol inside the passive containment, the geometric dimensions of the narrow slit on the passive containment, and the target condensation model, the droplet radius distribution data corresponding to the aerosol in the narrow slit is determined; Based on the droplet radius distribution data, the gravity settling velocity distribution data corresponding to the narrow slit is determined; Based on the gravity settling velocity distribution data, the aerosol retention efficiency corresponding to the narrow slit is determined.

2. The method according to claim 1, characterized in that, The step of determining the target condensation model corresponding to the passive containment based on the structural type of the passive containment includes: When the passive containment structure is a concrete structure, the target condensation model corresponding to the passive containment is determined to be a single-stage condensation model; When the passive containment structure is a composite structure, the target condensation model corresponding to the passive containment is determined to be a two-stage condensation model, and the composite structure includes a concrete structure and a metal structure; When the passive containment structure is a metallic structure, the target condensation model corresponding to the passive containment is determined to be a gradual condensation model.

3. The method according to claim 1, characterized in that, The step of determining the droplet radius distribution data corresponding to the aerosol in the narrow slit based on the initial droplet radius of the aerosol inside the passive containment, the geometric dimensions of the narrow slit on the passive containment, and the target condensation model includes: Based on the average carrier gas velocity, the initial gas temperature inside the containment, the geometric dimensions, and the target condensation model, convection-diffusion solutions are performed to obtain the temperature distribution data in the narrow slit. Based on the average carrier gas velocity, the initial vapor concentration inside the containment, the geometric data, and the target condensation model, convection-diffusion solution processing is performed to obtain vapor concentration distribution data in the narrow slit; Based on the temperature distribution data and the vapor concentration distribution data, the droplet radius distribution data is determined.

4. The method according to claim 3, characterized in that, The process of performing convection-diffusion solution based on the average carrier gas velocity, the gas temperature inside the containment, the geometric dimensional data, and the target condensation model to obtain the temperature distribution data in the narrow slit includes: When the geometry of the narrow slit is cylindrical, the temperature distribution data is obtained by iterative calculation based on the average carrier gas velocity, the initial gas temperature, the geometric dimension data, the target condensation model, and the first temperature convection-diffusion function.

5. The method according to claim 3, characterized in that, The process of performing convection-diffusion solution based on the average carrier gas velocity, the gas temperature inside the containment, the geometric dimensional data, and the target condensation model to obtain the temperature distribution data in the narrow slit includes: When the geometry of the narrow slit is a parallel plate structure, the temperature distribution data is obtained by iterative calculation based on the average carrier gas velocity, the initial gas temperature, the geometric dimension data, the target condensation model, and the second temperature convection-diffusion function.

6. The method according to claim 3, characterized in that, Determining the droplet radius distribution data based on the temperature distribution data and the vapor concentration distribution data includes: Based on the temperature distribution data, determine the saturated vapor pressure distribution data in the narrow slit; Based on the vapor concentration distribution data and the saturated vapor pressure distribution data, the saturation ratio distribution data in the narrow slit is obtained; The activation diameter distribution data in the narrow slit is determined based on the saturation ratio distribution data. Based on the vapor concentration distribution data and temperature distribution data, the droplet radius growth rate distribution data of aerosol in the narrow slit is determined; The droplet radius distribution data is determined based on the activated diameter distribution data, the droplet radius growth rate distribution data, and the initial droplet radius.

7. The method according to claim 6, characterized in that, Determining the activation diameter distribution data in the narrow slit based on the saturation ratio distribution data includes: Based on the correspondence between the saturation ratio distribution data and the Kelvin diameter, the Kelvin diameter distribution data is obtained; Based on the chemical properties of the aerosol, the Kelvin diameter distribution data is corrected to obtain the activated diameter distribution data.

8. The method according to claim 1, characterized in that, Based on the droplet radius distribution data, the gravity settling velocity distribution data corresponding to the narrow slit is determined, including: Based on the droplet radius distribution data, the droplet mixing density distribution data of aerosol in the narrow slit is determined; Based on the droplet radius distribution data, the droplet mixing density distribution data, and the correspondence between radius and velocity, the gravity settling velocity distribution data is obtained; The radius-velocity correspondence includes the correspondence between gravity settling velocity, droplet radius, and droplet mixing density.

9. The method according to claim 1, characterized in that, The geometric dimensions include the radial length of the narrow slit; The determination of the aerosol retention efficiency corresponding to the narrow slit based on the gravity settling velocity distribution data includes: Based on the gravity settling velocity distribution data, the target settling distance of aerosols in the narrow slit is determined; The aerosol retention efficiency is determined based on the target settling distance and the radial length of the narrow slit.

10. A device for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant, characterized in that, The device includes: The model selection module is used to determine the target condensation model corresponding to the passive containment based on the structural type of the passive containment. The radius calculation module is used to determine the droplet radius distribution data of the aerosol in the narrow slit based on the initial droplet radius of the aerosol inside the passive containment, the geometric dimension data of the narrow slit on the passive containment, and the target condensation model. The velocity calculation module is used to determine the gravity settling velocity corresponding to the narrow slit based on the droplet radius distribution data. The efficiency calculation module is used to determine the aerosol retention efficiency corresponding to the narrow slit based on the gravity settling velocity and the geometric dimension data.

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